OPTICAL WAVE GUIDE HAVING MULTIPLE INDEPENDENT OPTICAL PATH AND OPTICAL GAS SENSOR USING THAT
The present invention relates to optical wave guide having multiple independent optical path and optical gas sensor using that, having an effect of improving optical efficiency by elongating optical path and condensing incident light without a separate artificial structure, by using first focus points of multiple 3 dimensional elliptical mirrors as a common focus point and equipping a light source at a first focus point and optical sensor parts at each second focus points in an optical structure using multiple 3 dimensional elliptical mirrors, and by placing so that virtual lines of first elliptical mirror and second elliptical mirror form a constant angle for improving optical efficiency in a structure equipping a light source at a second focus point of any one of elliptical mirror of multiple 3 dimensional elliptical mirrors and optical sensor parts at each second focus points of another 3 dimensional elliptical mirror.
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This application claims the priority of Korean Patent Application No. 2014-0012013, filed on Feb. 3, 2014 in the KIPO (Korean Intellectual Property Office), which is incorporated herein by reference in its entirety.
DESCRIPTION1. Field of Invention
The present invention relates to optical wave guide having multiple independent optical path and optical gas sensor using that, and more particularly providing an optical wave guide having multiple independent optical path and Optical Gas Sensor using that that may condense light irradiating from a light source without a separate condenser within a range of tens˜hundreds μm from the center of an optical sensor part, and reducing loss of amount of light by realizing a structure with a long optical path and also a structure minimizing reflection of light and at the same time skillfully condensing light on an optical sensor part, and able to actively deal with secular changes of light source.
2. Background of Invention
Generally, optical wave guides are manufactured so that optical path lengths in the process when light emitted from a light source arrives at an optical sensor part are made long and at the same time efficiency of transmittance of light in respect to optical sensor part is maximized. Optical wave guides are core configurations of optical gas sensors, and a number of publications were made public before the application of the present invention.
Korean Patent No. 10-0694635, 10-0732708, 10-1088360 and Korean Patent Laid-open Publication 2013-82482 are basically realized in an elliptical structure, and Korean Patent Laid-open Publication No. 2009-121810 and Korean Patent Laid-open Publication No. 2011-59006 comprises a condenser in front of a sensor part. Meanwhile, Korean Patent Laid-open Publication No. 2009-91433 and Korean Patent Laid-open Publication No. 2011-11307 has a reference sensor or a reference light source for improvement of reliability of sensor characteristics.
Korean Patent No. 10-0694635 adopts a structure that uses only half of an elliptical dome shaped reflector (10) and directing light reflecting from the other half to an optical sensor (12) through a reflector. This structure is a structure using only less than half of light flux of an irradiating light, in the case of light irradiating and reflecting in lower flat surfaces, there are disadvantages of difficulty of adequately irradiating to an optical sensor (12) when passing though a filter attached to an optical sensor (12) due to refraction.
A light source (120) is installed at first focus point (111b, 112b) shared by a first ellipse (111a) and a second ellipse (112a). A first light detecting window (131) and a second light detecting window (132) transmit light reflected from a first elliptical mirror (111a) and a second elliptical mirror (112a). A photo sensor part (130) detects light transmitting through a first light detecting window (131) and a second light detecting window (132). This structure has advantages of being easily manufactured in small sized structures, and is a structure able to condense without additional lens. But, the optical wave guide (110) of Korean Patent No. 10-1088360 structurally inherits disadvantages of condensing maximum of only ¼ of light from two light detecting windows.
The structure proposed in Korean Patent Laid-open Publication 2013-82482 is a structure gathering light emitted by a light source placed on a first focus point F1 of a first parabolic mirror (151) by a light detector placed on second focus point F2 of second parabolic mirror (152). According to
The structure proposed in Korean Patent Laid-open Publication 2009-121810, as illustrated in
The structure proposed in Korean Patent Laid-open Publication 2011-59006, as illustrated in
The structure proposed in Korean Patent Laid-open Publication 2011-11307, as illustrated in
The structure proposed in Korean Patent Laid-open Publication 2009-91433, as illustrated in
T: absolute temperature, kB: Boltzmann constant, h: Planck constant,
c: velocity of light
As expressed in
Also, Beer-Lambert Law, which is applied broadly for infrared gas sensor manufacturing and applications, may be expressed as equation (2).
I=I0·(−αxl) equation(2)
Io: an initial light intensity, α: absorption coefficient for specific gas, x: density of gas, l: optical path.
To improve output of an infrared gas sensor, as equation (3) proposed by J. S. Park and S. H. Yi in Sensors and Materials (thesis in year 2011), it may be observed that an incident light arriving at an optical sensor part emulating a condensed shape rather than an initial optical pattern is effective.
ζ: proportional constant, η: radius of initial optical pattern, rd: radius of optical pattern at a sensor.
Looking into items that should be considered for manufacturing optical gas sensors as expressed in formula (1), (2), (3),
-
- 1) since light intensity of a light source decreases from secular change of its own filament, it should be appropriately compensated by sensing secular change according to time,
- 2) and when gas with long wavelengths is to be measured, it should be a high performance sensor able to sufficiently detect light or a structure able to improve light intensity because the intensity of light irradiating from a light source is small (from equations 1 to 3),
- 3) since optical path should be long for sensitivity of an infrared gas sensor to generate high output voltages at identical densities, optical structures should be manufactured to have a path as long as possible, and in this instance, a state that may minimize amount absorbed when reflecting from a structure should be ensured by minimizing reflection from an optical structure,
- 4) and should be equipped with a characteristic of incident light arriving at an optical sensor part to be collected in the center of an optical sensor part in a radius as small as possible and should reach inside field of view of an optical sensor.
The objective of the present invention is to provide an optical wave guide having multiple independent optical path and optical gas sensor using that that may condense light irradiating from a light source within tens˜hundreds μm radius (in other words, Field of View) from center of an optical sensor part without using a separate condenser.
Another objective of the present invention is to provide an optical wave guide having multiple independent optical path and optical gas sensor using that that reduces loss of amount of light and at the same time allows light to condense properly to an optical sensor part by realizing a structure with a long optical path and a structure minimizing reflection of light.
Another objective of the present invention is to provide an optical wave guide having multiple independent optical path and optical gas sensor using that that may actively deal with secular change of a light source.
The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee.
As illustrated in
When an optical wave guide for use for optical gas sensors is made in a shape of a 3 dimensional ellipsoid, even though volume increases, since all of the light irradiating from a light source positioned at a first focus point (F1) of a 3 dimensional elliptical mirror (411) is all condensed at an optical sensor part positioned at a second focus point (F2) of a 3 dimensional elliptical mirror (411), there is almost no loss of light. Also, incident light to an optical sensor part positioned at a second focus point (F2) of a 3 dimensional elliptical mirror is incident on a small concentric circle with a radius of tens˜hundreds of μm, and thus it is effective to manufacture filters, which is a standard component of an optical sensor part, and a structure in which it is able to accurately reach an infrared ray sensing part positioned below a filter.
When an optical wave guide having multiple independent optical path is realized by two 3 dimensional ellipsoids (401, 402), manly three installation positions for light source and optical sensor part may be intuitively assumed.
(1) A light source is installed at one of the second focus point (F2) of the two 3 dimensional ellipsoid (401, 402),
(2) an optical sensor part is installed at a first focus point (F1), which is a common focus point, and light sources are installed at each of the second focus points (F2) of the two 3 dimensional ellipsoids (401, 402),
(3) a light source is installed at a first focus point (F1), which is a common focus point, and optical sensors are installed at each of the second focus points (F2) of the two 3 dimensional ellipsoids (401, 402).
When an optical wave guide having multiple independent optical path is realized by two 3 dimensional ellipsoids (401, 402), installation positions for light sources and optical sensor parts are divided into the described three methods and results of simulation of shape of light flux arriving at optical sensor parts for each method is described below.
Referring to
When an optical wave guide (500) having multiple independent optical path is realized by three 3 dimensional ellipsoids (501, 502, 503), mainly five installation positions for light sources and optical sensor parts may be intuitively assumed.
(1) A light source is installed at a common focus point, and optical sensors are installed at each of the second focus points (F2) of the three 3 dimensional ellipsoids (501, 502, 503).
(2) An optical sensor is installed at a common focus point, and light sources are installed at each of the second focus points (F2) of the three 3 dimensional ellipsoids (501, 502, 503).
(3) Optical sensors are installed at each of the second focus points (F2) of first and second ellipsoids (501, 502) of three 3 dimensional ellipsoids (501, 502, 503), and a light source installed at a second focus point (F2) of third ellipsoid (503),
(4) An optical sensor is installed at a second focus point (F2) of a first ellipsoid (501) of three 3 dimensional ellipsoids (501, 502, 503), and light sources are installed at second focus points (F2) of second and third ellipsoids (502, 503),
(5) A light source is installed at a second focus point (F2) of a first ellipsoid (501) of three 3 dimensional ellipsoids (501, 502, 503), and optical sensors are installed at second focus points (F2) of second and third ellipsoids (502, 503).
As an example, when an optical wave guide (500) having multiple independent optical path has an optical sensor installed at a first focus point (F1), which is a common focus point of three 3 dimensional ellipsoids (501, 502, 503), and light sources installed at each of the second focus points (F2) of the three 3 dimensional ellipsoids (501, 502, 503), it is preferable to select the third angle (θ23) formed by a virtual reference line (C22) connecting a first focus point and a second focus point of a second ellipsoid (502) and a virtual reference line (C23) connecting a first focus point and a second focus point of a third ellipsoid (503), to be from a range of 20 degrees or over and 60 degrees or below.
For another example, when an optical wave guide (500) having multiple independent optical path has light source installed at a second focus point (F2) of a second ellipsoid (502) of three 3 dimensional ellipsoids (501, 502, 503), and optical sensors installed at second focus points (F2) of each first and third ellipsoids (501, 503), it is preferable to select the third angle (θ23) formed by a virtual reference line (C22) connecting first focus point and second focus point of second ellipsoid (502) and a virtual reference line (C23) connecting first focus point and second focus point of third ellipsoid (503), to be from a range of 20 degrees or over and 60 degrees or below.
For another example, when an optical wave guide (500) having multiple independent optical path has optical sensors installed at second focus points (F2) of second and third ellipsoids (501, 502) of three 3 dimensional ellipsoids (501, 502, 503), and a light source installed at a second focus point (F2) of a first ellipsoid (503),), it is preferable to select the third angle (θ23) formed by a virtual reference line (C22) connecting first focus point and second focus point of second ellipsoid (502) and a virtual reference line (C23) connecting first focus point and second focus point of third ellipsoid (503), to be from a range of 20 degrees or over and 60 degrees or below.
Referring to
As can be seen in
an optical wave guide is realized by two 3 dimensional elliptical mirrors, a light source is installed at a second focus point (F2) of one of the elliptical mirrors, and a optical sensor part is installed at a second focus point (F2) of another elliptical mirror.
First, referring to
An optical wave guide (410) having multiple independent optical path in accordance with
Results of simulation of shape of light flux arriving at an optical sensor part installed at a second focus point (F2) of a second elliptical mirror (412) is illustrated in
When a light source is installed at a second focus point (F2) of a first elliptical mirror (411), and an optical sensor is installed at a second focus point (F2) of a second elliptical mirror (412), energy of incident light per unit area according to an angle (θ11) between two virtual reference lines (C11, C12) of two 3 dimensional elliptical mirrors (411, 412) is illustrated as
But, even if an optical wave guide (410) with an angle (θ11) between two virtual reference lines (C11, C12) of 30 degrees is manufactured, if a light source, which should be installed at a second focus point (F2) of a first elliptical mirror (411), deviates ±1 mm from a second focus point (F2) by an error in manufacturing process or assembly, it may be predicted that it may show signs of energy of incident light to an optical sensor part positioned at a second focus point (F2) of a second elliptical mirror (412) reducing by a square of about 1 or more—here, shows an energy state almost similar to a structure with an angle (θ11) of over 50 degrees between virtual reference lines (C11, C12)—so careful attention during manufacturing process is required.
When putting above results together, it illustrates that even when manufacturing error of a light source, which should be installed at a second focus point (F2) of a first elliptical mirror (411), deviating ±1 mm from a second focus point (F2) occur, a focus point of a light source set to a positive direction from a second focus point (F2) of a first elliptical mirror (411) is relatively less influential to optical sensor manufacturing and characteristics than manufacturing error occurring in a negative direction.
Example 2an optical wave guide is realized by two 3 dimensional elliptical mirrors, an optical sensor part is installed at a first focus point (F1), which is a common focus point, and light sources are installed at each second focus points (F2) of two 3 dimensional elliptical mirrors
As in example 2, when an optical wave guide is configured, it is difficult to condense light irradiating from two light sources within tens˜hundreds μm radius (in other words, Field of View) from the center of an optical sensor part. The reason is that light irradiating from two light sources causes interference.
Example 3an optical wave guide is realized by two 3 dimensional elliptical mirrors, a light source is installed at a first focus point (F1), which is a common focus point, and optical sensor parts are installed at each second focus points (F2) of two 3 dimensional elliptical mirrors
First, referring to
An optical wave guide (420) having multiple independent optical path in accordance with
Therefore, in can be observed that when optical sensor parts to measure gas with similar absorption bands (i.e. HC series, carbon monoxide, carbon dioxide) is installed at one of the second focus points (F2), sensing characteristics of sensor improves, and when one side is used as a reference for compensating for amount of light, since sensing of sensor is compensated without additional separate light sources, long-term reliability may be improved.
When an optical wave guide (420) having multiple independent optical path has a light source is installed at a first focus point (F1), which is a common focus point, and optical sensors are installed at each of the second focus points (F2) of the two 3 dimensional elliptical mirrors (421, 422), as can be seen in
As illustrated in
when an optical wave guide is realized by three elliptical mirrors
An optical wave guide (510) having multiple independent optical path in accordance with
As an example, an angle (θ21) formed by a reference line connecting a first focus point (F1) and a second focus point (F2) of a first elliptical mirror (511) and a reference line connecting a first focus point (F1) and a second focus point (F2) of a second elliptical mirror (512), and an angle (θ22) formed by a reference line connecting a first focus point (F1) and a second focus point (F2) of a first elliptical mirror (511) and a reference line connecting a first focus point (F1) and a second focus point (F2) of a third elliptical mirror (513) are formed to have same angles with each other.
As illustrated in
As illustrated in
When putting results of
Carbon monoxide (infrared ray absorption wavelength: ˜4.6 μm) emitted from breath shows a concentration of lower than about 20 ppm, but TVOCs (infrared ray absorption wavelength about 3.4 μm) and ethanol ((infrared ray absorption wavelength about 9.4 μm) shows concentration of about 80˜100 ppm levels.
To Identify drunk driving results from concentration of ethanol emitting from the lungs when absorbed in the body, since a large amount of H—C compounds is emitted through breath after drinking, infrared sensor with long wavelengths (˜9.4 μm) should be used for accurate concentration measurements. But, as illustrated in
From the optical simulations provided above,
1) compared to patents provided in Korean Patent No. 10-0694635/10-0732708 and 10-1088360 and Korean Patent Laid-open Publication 2013-0058781, the structure of
2) compared to Korean Patent No. 10-2008-0047896 and to Korean Patent No. 10-2009-0115590, since irradiating light may be effectively condensed without using a separate condenser and irradiate to an optical sensor part, there are advantages of having no factors of cost increase.
3) compared to Korean Patent No. 10-2008-0016685 and to Korean Patent No. 10-2009-0068892, a reference sensor may be equipped at a first optical sensor part, and by installing a sensor measuring gas, which is a target for measurement, at a second optical sensor part of a structure with a form of structure in
That is, as an example, when intending to manufacture an optical gas sensor for measuring drinking, if a carbon monoxide sensor with a wavelength absorption of 4.6 μm is placed at a first optical sensor part, and an ethanol sensor with a wavelength absorption of 4.6 μm is placed at a second optical sensor part and light source is illuminated, relatively large amount of energy absorption is possible during initial operation of the sensor, and selection in respect to other gas is excellent, and considering that there are almost no carbon monoxide in the atmosphere, output status of light source based on sensor output is checked, and by comparative evaluation of output of ethanol sensor applying this, sensitivity change of sensor according to secular change of light source is compensated, and thus may equip characteristics of securing long-term reliability.
Therefore, manufacturing sensor with all of the characteristics of an infrared optical gas sensor mentioned individually in the described registered and applied patents, and raised up in the beginning of the present invention, in which
1) a structure that may actively deal with secular change of a infrared ray light source,
2) a high performance sensor or structure that may improve light intensity,
3) a structure with a long optical path, and a structure that minimizes reflections inside,
4) irradiating in a field of view of an optical sensor part by incident light arriving at an optical sensor part is focused to a small radius at the center of an optical sensor is possible.
Also, by installing gas inlet (a structure that pushes in gas to measure ethanol or optical structure used for measuring gas by suctioning outside air using a small pump) and an outlet in areas with low spatial density of infrared rays, manufacturing an optical sensor without decrease in optical efficiency is possible.
Although exemplary embodiments have been described herein, it should be understood by those skilled in the art that these embodiments are given by way of illustration only, and that various modifications, variations and alterations can be made without departing from the spirit and scope of the invention. The scope of the present invention should be defined by the appended claims and equivalents thereof.
Claims
1. An optical wave guide having multiple independent optical path comprising multiple elliptical mirrors formed along a portion of entire trajectories of 3 dimensional ellipsoids, and the multiple elliptical mirrors are formed to share each first focus points as a common focus point and virtual reference lines connecting each first focus point and second focus point forms a constant angle with each other.
2. An optical wave guide having multiple independent optical path according to claim 1, wherein when a light source is positioned at the common focus point and optical sensor parts are positioned at each second focus points of the multiple elliptical mirrors, constant angle formed by virtual reference lines connecting the first focus point and second focus point is selected from a range of 10 degrees or over and 180 degrees or below.
3. An optical wave guide having multiple independent optical path comprising multiple elliptical mirrors formed along a portion of entire trajectories of 3 dimensional ellipsoids, the multiple elliptical mirrors comprises a first elliptical mirror formed along a portion of an entire trajectory of a first ellipsoid, and a second elliptical mirror formed along a portion of an entire trajectory of a second ellipsoid sharing a first focus point with a first elliptical mirror, and when an optical sensor part is positioned at a second focus point of the first elliptical mirror, and a light source is positioned at a second focus point of the second elliptical mirror, constant angle formed by a virtual reference line connecting a first focus point and a second focus point of the first elliptical mirror and a virtual reference line connecting a first focus point and a second focus point of the second elliptical mirror is selected from a range of 10 degrees or over and 30 degrees or below.
4. An optical wave guide having multiple independent optical path comprising multiple elliptical mirrors formed along a portion of entire trajectories of 3 dimensional ellipsoids, the multiple elliptical mirrors comprises a first elliptical mirror formed along a portion of an entire trajectory of a first ellipsoid, a second elliptical mirror formed along a portion of an entire trajectory of a second ellipsoid sharing a first focus point with the first elliptical mirror, and a third elliptical mirror formed along a portion of an entire trajectory of a third ellipsoid sharing a first focus point with the first elliptical mirror, and the first elliptical mirror and the second elliptical mirror is formed that a virtual reference line connecting a first focus point and a second focus point of the first elliptical mirror and a virtual reference line connecting a first focus point and a second focus point of the second elliptical mirror forms a first angle, and the first elliptical mirror and the third elliptical mirror is formed that a virtual reference line connecting a first focus point and a second focus point of the first elliptical mirror and a virtual reference line connecting a first focus point and a second focus point of the third elliptical mirror forms a second angle, and the second elliptical mirror and the third elliptical mirror is formed that a virtual reference line connecting a first focus point and a second focus point of the second elliptical mirror and a virtual reference line connecting a first focus point and a second focus point of the third elliptical mirror forms a third angle, and the first angle and the second angle are formed to have identical angles with each other.
5. An optical wave guide having multiple independent optical path according to claim 4, wherein when an optical sensor part is positioned at a first focus point, which is a common focus point of the multiple elliptical mirrors, and light sources are positioned at each second focus points of the first, second, and third elliptical mirrors, a third angle formed by a virtual reference line connecting a first focus point and a second focus point of the second elliptical mirror and a virtual reference line connecting a first focus point and a second focus point of the third elliptical mirror is selected from a range of 20 degrees or over and 60 degrees or below.
6. An optical wave guide having multiple independent optical path according to claim 4, wherein when light source is positioned at a second focus point of the second elliptical mirror, and optical sensor parts are positioned at each second focus points of the first and third elliptical mirrors, a third angle formed by a virtual reference line connecting a first focus point and a second focus point of the second elliptical mirror and a virtual reference line connecting a first focus point and a second focus point of the third elliptical mirror is selected from a range of 20 degrees or over and 60 degrees or below.
7. An optical wave guide having multiple independent optical path according to claim 4, wherein when light source is positioned at each second focus points of the second elliptical mirror and the third elliptical mirror, and an optical sensor part is positioned at a second focus point of the first elliptical mirror, a third angle formed by a virtual reference line connecting a first focus point and a second focus point of the second elliptical mirror and a virtual reference line connecting a first focus point and a second focus point of the third elliptical mirror is selected from a range of 10 degrees or over and 180 degrees or below.
8. An optical wave guide having multiple independent optical path according to claim 4, wherein when optical sensor parts are positioned at second focus points of the second elliptical mirror and the third elliptical mirror, and a light source is positioned at a second focus point of the first elliptical mirror, a third angle formed by a virtual reference line connecting a first focus point and a second focus point of the second elliptical mirror and a virtual reference line connecting a first focus point and a second focus point of the third elliptical mirror is selected from a range of 20 degrees or over and 60 degrees or below.
9. An optical gas sensor comprising a first elliptical mirror formed along a portion of an entire trajectory of a first ellipsoid, and a second elliptical mirror formed along a portion of an entire trajectory of a second ellipsoid sharing a first focus point with the first elliptical mirror, and comprising,
- an optical wave guide, in which the first elliptical mirror and the second elliptical mirror form a constant angle, which is formed by a virtual reference line connecting a first focus point and a second focus point of the first elliptical mirror and a virtual reference line connecting a first focus point and a second focus point of the second elliptical mirror;
- a light source emitting light installed at a first focus point shared by a first elliptical mirror and a second elliptical mirror of the optical wave guide; and
- a first and second optical sensor installed at a second focus point shared by a first and a second elliptical mirror of the optical wave guide part transmitting light from the light source.
10. An optical gas sensor comprising a first elliptical mirror formed along a portion of an entire trajectory of a first ellipsoid, and a second elliptical mirror formed along a portion of an entire trajectory of a second ellipsoid sharing a first focus point with the first elliptical mirror, and comprising,
- an optical wave guide, in which the first elliptical mirror and the second elliptical mirror form a constant angle, which is formed by a virtual reference line connecting a first focus point and a second focus point of the first elliptical mirror and a virtual reference line connecting a first focus point and a second focus point of the second elliptical mirror;
- a light source emitting light installed at a second focus point of a first elliptical mirror of the optical wave guide; and
- an optical sensor installed at a second focus point of a second elliptical mirror of the optical wave guide part transmitting light from the light source.
11. An optical gas sensor according to claim 10, wherein the first elliptical mirror and the second elliptical mirror are realized by selecting a constant angle, which is formed by a virtual reference line connecting a first focus point and a second focus point of the first elliptical mirror and a virtual reference line connecting a first focus point and a second focus point of the second elliptical mirror, from a range of 10 degrees or over and 30 degrees or below.
12. An optical gas sensor according to claim 9, wherein the optical gas sensor further comprises, on a side part of the optical wave guide, a gas inlet, to which gas flows into, installed where spacial density of light emitting from a light source is low and a gas outlet installed separated from the gas inlet, and gas inlet and gas outlet of the optical wave guide maintains sealing.
13. An optical gas sensor comprising a first elliptical mirror formed along a portion of an entire trajectory of a first ellipsoid, a second elliptical mirror formed along a portion of an entire trajectory of a second ellipsoid sharing a first focus point with the first elliptical mirror, and a third elliptical mirror formed along a portion of an entire trajectory of a third ellipsoid sharing a first focus point with the first elliptical mirror, and comprising,
- an optical wave guide, in which the first elliptical mirror and the second elliptical mirror form a first angle, which is formed by a virtual reference line connecting a first focus point and a second focus point of the first elliptical mirror and a virtual reference line connecting a first focus point and a second focus point of the second elliptical mirror, the first elliptical mirror and the third elliptical mirror form a second angle, which is formed by a virtual reference line connecting a first focus point and a second focus point of the first elliptical mirror and a virtual reference line connecting a first focus point and a second focus point of the third elliptical mirror, and the second elliptical mirror and the third elliptical mirror form a third angle, which is formed by a virtual reference line connecting a first focus point and a second focus point of the second elliptical mirror and a virtual reference line connecting a first focus point and a second focus point of the third elliptical mirror, and the first angle and the second angle forms identical angles with each other.
- a light source emitting light installed at a first focus point shared by first, second, and third elliptical mirror of the optical wave guide; and
- multiple optical sensors each installed at second focus points of first, second, and third elliptical mirror of the optical wave guide transmitting light from the light source.
14. An optical gas sensor comprising a first elliptical mirror formed along a portion of an entire trajectory of a first ellipsoid, a second elliptical mirror formed along a portion of an entire trajectory of a second ellipsoid sharing a first focus point with the first elliptical mirror, and a third elliptical mirror formed along a portion of an entire trajectory of a third ellipsoid sharing a first focus point with the first elliptical mirror, and comprising,
- an optical wave guide, in which the first elliptical mirror and the second elliptical mirror form a first angle, which is formed by a virtual reference line connecting a first focus point and a second focus point of the first elliptical mirror and a virtual reference line connecting a first focus point and a second focus point of the second elliptical mirror, the first elliptical mirror and the third elliptical mirror form a second angle, which is formed by a virtual reference line connecting a first focus point and a second focus point of the first elliptical mirror and a virtual reference line connecting a first focus point and a second focus point of the third elliptical mirror, and the second elliptical mirror and the third elliptical mirror form a third angle, which is formed by a virtual reference line connecting a first focus point and a second focus point of the second elliptical mirror and a virtual reference line connecting a first focus point and a second focus point of the third elliptical mirror, and the first angle and the second angle forms identical angles with each other.
- multiple light sources emitting light installed at second focus points of each second and third elliptical mirrors of the optical wave guide; and
- an optical sensors each installed at a second focus point of a first elliptical mirror of the optical wave guide transmitting light from the light source.
15. An optical gas sensor comprising a first elliptical mirror formed along a portion of an entire trajectory of a first ellipsoid, a second elliptical mirror formed along a portion of an entire trajectory of a second ellipsoid sharing a first focus point with the first elliptical mirror, and a third elliptical mirror formed along a portion of an entire trajectory of a third ellipsoid sharing a first focus point with the first elliptical mirror, and comprising,
- an optical wave guide, in which the first elliptical mirror and the second elliptical mirror form a first angle, which is formed by a virtual reference line connecting a first focus point and a second focus point of the first elliptical mirror and a virtual reference line connecting a first focus point and a second focus point of the second elliptical mirror, the first elliptical mirror and the third elliptical mirror form a second angle, which is formed by a virtual reference line connecting a first focus point and a second focus point of the first elliptical mirror and a virtual reference line connecting a first focus point and a second focus point of the third elliptical mirror, and the second elliptical mirror and the third elliptical mirror form a third angle, which is formed by a virtual reference line connecting a first focus point and a second focus point of the second elliptical mirror and a virtual reference line connecting a first focus point and a second focus point of the third elliptical mirror, and the first angle and the second angle forms identical angles with each other.
- a light source emitting light installed at second focus points of a first elliptical mirror of the optical wave guide; and
- multiple optical sensors each positioned at second focus points of second and third elliptical mirrors of the optical wave guide transmitting light from the light source.
16. An optical gas sensor according to claim 15, wherein the second elliptical mirror and the third elliptical mirror are realized by selecting a third angle, which is formed by a virtual reference line connecting a first focus point and a second focus point of the second elliptical mirror and a virtual reference line connecting a first focus point and a second focus point of the third elliptical mirror, from a range of 20 degrees or over and 60 degrees or below.
17. An optical gas sensor according to claim 15, wherein one of the multiple optical sensor part is a first gas sensor used for tracking secular change of the light source, and another one is a second gas sensor sensing gas, which users want to identify.
18. An optical gas sensor according to claim 13, wherein the optical gas sensor further comprises, on a side part of the optical wave guide, a gas inlet, to which gas flows into, installed where spacial density of light emitting from a light source is low and a gas outlet installed separated from the gas inlet, and gas inlet and gas outlet of the optical wave guide maintains sealing.
Type: Application
Filed: Apr 29, 2014
Publication Date: Aug 6, 2015
Applicant: Korea National University of Transportation Industry-Academic Cooperation Foundation (Chungju-si)
Inventors: Seung Hwan LEE (Chungju-si), Sung Ho JANG (Seoul), Sang Ho JUNG (Seongnam-si)
Application Number: 14/264,575