KR101456273B1 - Optical system for measurement gas - Google Patents

Abstract

The present invention relates to an optical system for measuring gas, which comprises: an infrared light source unit which radiates a first infrared ray in a specific wavelength band; a parallel light lens which converts the infrared ray into parallel light; a gas cell where an infrared ray transmitting window is formed in order to transmit the parallel light; a cylindrical focusing lens which converts the parallel light that has passed the gas cell into focusing oval light; a measurement light measuring unit which is positioned within the range of the focusing oval light in order to measure measurement light; and a reference light measuring unit which is positioned within the range of the focusing oval light, is placed in parallel to the measurement light measuring unit in a vertical direction to the optical axis of the first infrared ray, and measures reference light. In addition, the infrared light source unit, the parallel light lens, the gas cell, and the cylindrical focusing lens are positioned in the optical axis of the first infrared ray.

Description

[0001] The present invention relates to an optical system for measuring gas,

The present invention relates to a gas measuring optical system that enables gas measurement by an infrared optical method.

Now, a gas measuring optical system capable of measuring a gas using an infrared optical system has been developed and used. An example of such a conventional gas measuring optical system is shown in US Pat. Nos. US7432508 and US513436.

More specifically, the conventional gas measuring optical system including the US Pat. No. 7,432,508 and US Pat. No. 5,134,363 is schematically shown in FIG. 1 is a configuration diagram of a gas measuring optical system using infrared rays according to a conventional example.

As shown in FIG. 1, a conventional gas measuring optical system using infrared rays includes an infrared light source 1 for infrared radiation, a parallel light lens 2 for converting infrared rays emitted from an infrared light source into parallel light L1, A gas cell 3 in which a measurement gas containing an infrared ray transmission window 3a can be filled, a condenser lens 4 in a spherical rotationally symmetric shape capable of condensing the infrared ray passing through the gas cell into an infrared light sensor, A reference light L 2 and a reference light L 3 and a measurement light filter 6 and a reference light filter 8 capable of transmitting only a specific wavelength band and the respective filters 6 and 8 And a measurement light sensor 7 and a reference light sensor 9 for measuring the intensity change of one transmitted light.

In the conventional gas measuring optical system using infrared rays, the optical isolator 5 is used to separately measure the measurement light and the reference light, so that the path of the reference light L 3 is the optical axis of the parallel light L 1 (that is, (I.e., the optical axis of the infrared ray irradiated by the light source). The optical axis is the z-axis with reference to the coordinates shown in Fig.

That is, the reference light filter 9 and the reference light sensor 9 are provided on the optical axis of the reference light 3 in order to measure the reference light L3.

As shown in (a), the conventional gas measuring optical system having the above-described structure is configured to form a parallel light L1 having a circular cross section and having a predetermined size as an extension of infrared rays. As shown in (b) The measurement light L2 and the reference light L3 which are obtained by reducing the parallel light L1 are produced and provided to the respective sensors 7 and 9. That is, the measurement light L2 and the reference light L3 are smaller in diameter than the parallel light L1 and have a circular section.

In the conventional gas measuring optical system using infrared rays, since the optical axes of the optical elements 6 and 7 and 8 and 9 must be aligned with respect to the measurement light L2 and the reference light L3, respectively, It is difficult to arrange the optical sensors separately.

Further, since the conventional gas measuring optical system using infrared rays differs in the direction in which the measurement light L2 and the reference light L3 are formed, the optical sensors are arranged on one circuit board and the optical axis alignment can not be performed. There is a problem that the sensors must be arranged and aligned on the respective optical axes.

An object of the present invention is to provide a gas measuring optical system capable of measuring measurement light and reference light in the axial direction of parallel light by using a cylindrical condensing lens without using an optical isolator.

According to another aspect of the present invention, there is provided an optical sensor comprising: a plurality of optical sensors arranged in a row; And to measure the reference light with the same light distribution at the same time.

According to an aspect of the present invention, there is provided a gas measuring optical system. The gas measuring optical system includes an infrared light source section for emitting a first infrared ray in a specific wavelength band, a parallel optical lens for converting the infrared ray into parallel light, a gas cell having an infrared ray transmitting window for transmitting the parallel light, A cylindrical condensing optical lens for converting the collimated light into focused differentiated light, a measurement light measurement unit for measuring measurement light positioned within the range of the focused atmospheric light, and a measurement light measurement unit positioned within the range of the focused, Wherein the infrared light source unit, the parallel light lens, the gas cell, and the cylindrical condensing optical lens are arranged in parallel in a direction perpendicular to the optical axis of the first infrared light, and the reference light measurement unit measures the reference light, It is located on the optical axis of infrared rays.

The cylindrical condensing optical lens includes a cylindrical lens having a flat surface facing the infrared light source portion and a surface opposite to the one surface of the cylindrical lens having a convex shape in the optical axis direction of the first infrared ray and a cylindrical surface facing the infrared light source portion, A cylindrical convex lens having a plane and an opposite surface on one side having different curvature radii with respect to a direction of an optical axis of the first infrared ray and a direction of a vertical axis different from one axial direction; And a cylindrical convex lens having different radii of curvature in different axial directions perpendicular to each other with respect to the optical axis direction of the first infrared ray.

Wherein the convergent tangential light is an elliptical light having the same length in the first axial direction perpendicular to the optical axis and shorter in the second axial direction perpendicular to the optical axis and the first axis than the balanced light, A length in a first axial direction perpendicular to the optical axis and a length in a second axial direction perpendicular to the optical axis and the first axis are both shorter than the equilibrium light.

And the parallel optical lens is a spherical or aspherical rotationally symmetric convex lens or hemispherical convex lens.

The material of the parallel optical lens and the cylindrical focusing optical lens is one of silicon (Si), germanium (Ge), CaF2, and sapphire (Al2O3) which can be used in the infrared band.

Wherein when the material of the parallel optical lens and the cylindrical focusing optical lens is silicon, the surface of the parallel optical lens and the cylindrical focusing optical lens is coated with anti-reflective coating to increase the transmittance.

The measurement light sensor included in the measurement light measurement unit and the reference light sensor included in the reference light measurement unit are formed on one circuit board.

According to the embodiment of the present invention, since the measurement optical sensor arranged in a line using the cylindrical condensing lens and the focused focused light corresponding to the reference light sensor are formed, a light separator for making the measurement light and the reference light is not required, Accordingly, the optical system configuration can be simplified.

Also, according to the embodiment of the present invention, the measurement light and the reference light can be measured simultaneously by arranging the measurement light sensor and the reference light sensor in the focused other light, and the photo-electric conversion efficiency can be increased.

In addition, according to the embodiment of the present invention, since the measurement optical sensor and the reference light sensor can be arranged in a line, the optical axis alignment is easy compared with the conventional technology, and since the optical sensors can be arranged in a line on a single circuit board, And circuit assemblies are easy to assemble.

1 is a configuration diagram of a gas measuring optical system using infrared rays according to a conventional example.
2 is a configuration diagram of a gas measuring optical system according to an embodiment of the present invention.
3 is a view showing the gas measuring optical system according to the embodiment of the present invention in the yz plane direction.
4 is a view showing the gas measurement optical system according to the embodiment of the present invention in the xz plane direction.
5 is a view showing parallel light and condensed light in the gas measuring optical system according to the embodiment of the present invention.
6 to 8 are views showing a modification of the cylindrical focusing optical lens in the gas measuring optical system according to the embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

Now, a gas measuring optical system according to an embodiment of the present invention will be described in detail with reference to the drawings.

2 is a configuration diagram of a gas measuring optical system according to an embodiment of the present invention. 2, the gas measuring optical system according to the embodiment of the present invention includes an infrared light source unit 10, a parallel optical lens 20, a gas cell 30, a cylindrical condensing optical lens 40, (50) and a reference light measuring unit (60).

The infrared light source unit 10 emits infrared rays in an absorption wavelength band of a gas to be measured. The parallel optical lens 20 is located on the optical axis of the infrared light emitted from the infrared light source unit 10 and converts the infrared light emitted from the infrared light source unit 10 into infrared light parallel to the infrared light axis, that is, parallel light L10.

Here, the material of the parallel optical lens 20 is silicon (Si), germanium (Ge), CaF2, sapphire (Al2O3) or the like which can be used in the infrared band. Increase the transmittance by anti-reflective coating.

The parallel optical lens may have a spherical or aspheric rotationally symmetrical convex lens shape or a hemispherical convex lens shape.

The gas cell 30 is located on the optical axis of infrared rays emitted from the infrared light source unit 10 and transmits the parallel light L10 converted by the parallel light lens 20. The gas cell 30 includes an infrared ray transmitting window 30a which allows gas to be measured to be sealed therein and allows parallel light L10 to be transmitted through two side surfaces (opposite sides) located on the optical axis of the parallel rays L10 Is formed.

The cylindrical condensing optical lens 40 is a cylindrical lens and is disposed at the optical axis of infrared rays emitted from the infrared light source unit 10 and is a condensing type of collimated light L10 passing through the gas cell 30 Hereinafter referred to as "convergent chromatic light"). To this end, the cylindrical focusing optical lens 40 has a convex shape at least on one side of at least two measuring surfaces 50 and 60 facing each other located on the optical axis of parallel light.

As the material of the cylindrical focusing optical lens 40, silicon (Si), germanium (Ge), CaF2, sapphire (Al2O3) or the like which can be used in the infrared band is used, Non-reflective coating on the surface to increase the transparency.

The measuring light measuring unit 50 is disposed parallel to the optical axis of the infrared light emitted from the infrared light source unit 10 and detects infrared light of a specific wavelength band to be measured in the focused other light focused by the cylindrical focusing optical lens 40 I.e., measurement light), and measures the intensity change of the received measurement light L20.

More specifically, the measurement light measuring unit 50 includes a measurement light filter 51 for transmitting only infrared rays of a specific wavelength band, a measurement light sensor 51 for measuring the intensity of the measurement light L20 filtered by the measurement light filter 51, (52).

Here, the measurement light filter 51 is, for example, an infrared band-pass measurement filter, and the center wavelength of the band-pass infrared ray transmission band of the filter 51 coincides with the absorption infrared wavelength of the measurement gas.

The reference light measuring unit 60 is positioned parallel to the optical axis of infrared rays emitted from the infrared light source unit 10. [ At this time, the reference light measuring unit 60 is positioned in parallel with the measurement light measuring unit 50 in a direction perpendicular to the optical axis of infrared rays.

The reference light measuring unit 60 receives the infrared ray (i.e., reference light) of a specific wavelength band to be referred to from the focused light (that is, the converged other light) focused by the cylindrical focusing optical lens 40, L30) is measured. Here, the reference light L30 is used for compensating for the measurement light L20 by measuring the change factors such as the intensity change of the light source.

More specifically, the reference light measuring unit 60 includes a reference light filter 61 that transmits only infrared rays of a specific wavelength band and a reference light sensor 62 that measures the intensity of the reference light L30 filtered by the reference light filter 61 do.

Here, the reference light filter 61 is, for example, an infrared band-pass filter, and the band-pass infrared ray transmission band of the filter 61 is selected by using an infrared ray band which does not overlap with the transmission band of the measurement filter. For the measurement light sensor 52 and the reference light sensor 62, a thermopile, a bolometer infrared sensor, PbSe, or the like is used.

The reference light sensor 62 measures a change factor such as an intensity change of the infrared light source and is used as a reference signal for correction of a signal measured by the measurement light sensor 52.

Many gases have absorption spectra in certain infrared bands. Therefore, when the infrared ray band light is passed through the gas existing in the gas cell, the specific infrared ray wavelength band is absorbed and the infrared ray of the other band is passed without being absorbed.

Therefore, it is possible to measure the gas type and the gas concentration existing in the gas cell 30 by measuring the infrared band absorbed by the gas and the intensity of the absorbed gas. That is, by comparing the intensity of light measured by the measurement light sensor 52 with the intensity of infrared rays radiated from the infrared light source unit 10 to grasp the change in the light intensity and grasping the infrared band absorbed by the gas, And the concentration of gas in each kind can be grasped.

Since the measuring light measuring unit 50 and the reference light measuring unit 60 are positioned in parallel to the optical axis of the parallel light, the gas measuring optical system according to the embodiment of the present invention includes the measuring light measuring unit 50 and the reference light measuring unit 60 Can be formed on one circuit board. Of course, only the measurement light sensor 52 of the measurement light measuring unit 50 and the reference light sensor 62 of the reference light measuring unit 60 can be formed on one circuit board.

Hereinafter, the operation of the gas measuring optical system according to the embodiment of the present invention will be described with reference to FIGS. 3 and 4. FIG.

FIG. 3 is a view showing a gas measurement optical system according to an embodiment of the present invention in the yz plane direction, and FIG. 4 is a view showing a gas measurement optical system according to an embodiment of the present invention in the xz plane direction.

The infrared light source unit 10 emits infrared rays in the absorption wavelength band of the gas to be measured and the emitted infrared rays are converted into the parallel light L10 by the parallel light lens 20.

The parallel light L10 passes through the gas cell 30 through the infrared transmitting window 30a formed on the side surface of the gas cell 30. [ At this time, the parallel light L10 is absorbed in the gas cell 30 in proportion to the concentration of the gas to be measured.

The parallel light L10 transmitted through the gas cell 30 is incident on the cylindrical condensing optical lens 40. The cylindrical condensing optical lens 40 irradiates the parallel light L10 to the measuring light measuring unit 50, And is focused on the measuring unit 60.

When the focused light focused by the cylindrical focusing optical lens 40 is viewed from the yz plane at this time, the focused light is detected by the measurement light sensor 52 and the reference light sensor 62, as shown in FIG. 3 (a) And shows the same light intensity distribution. The focused light intensity increases the electrical signal conversion efficiency of each optical sensor 52, 62.

When the focused light focused by the cylindrical focusing optical lens 40 is viewed from the xz plane, the focused light passes through the position of the measurement light sensor 52 and the position of the reference light sensor 62 as shown in FIG. 4 (a) In the direction of the sensor array in the x-axis direction. In FIG. 4 (a), a1 is the x-axis direction light intensity distribution in the reference light sensor 62, and a2 is the x-axis light intensity distribution in the measurement light sensor 52.

Hereinafter, with reference to FIG. 5, the intensity distribution and the shape of light focused by the cylindrical focusing optical lens 40 described with reference to FIG. 3A and FIG. 4A will be described in more detail.

5 is a view showing parallel light and condensed light in the gas measuring optical system according to the embodiment of the present invention. The parallel light L10 formed by the parallel light lens 20 shows a form in which the infrared rays emitted from the infrared light source unit 10 are expanded and have a constant size as shown in FIG.

When the collimated light L10 is converged by the cylindrical focusing optical lens 40, the collimated light L10 is condensed in the y-axis direction as shown in Fig. 3 (a) (I.e., a shape in which the radius in the x-axis direction is equal to that in the parallel light) is shown in the x-axis direction. That is, the converging light has an elliptical shape having a long length in the x-axis direction. Accordingly, the focusing light according to the present invention is referred to as a focusing neutron.

The measurement light sensor 52 and the reference light sensor 62 are positioned in a row in the range of the convergent light of the above-described order so that the measurement light sensor 52 and the reference light sensor 62 measure light having the same light intensity distribution It is possible to measure the reference light L20 and the reference light L30.

Meanwhile, the gas measuring optical system according to the embodiment of the present invention can modify the cylindrical focusing optical lens 40 to make the focused optical beam as shown in FIG. 5 (c). 5 (c) has a shorter length in the x-axis direction as compared with the convergent ternary light shown in Fig. 5 (b). In other words, the focused atrium light shown in FIG. 5 (c) is focused on both the x-axis direction and the y-axis direction in comparison with the parallel light L10.

As a result, the gas measuring optical system according to the embodiment of the present invention forms elliptical focusing light converged only in one axial direction (one of the y axis direction or the x axis direction) according to the cylindrical condensing optical lens 40 to be used, It is possible to form an elliptical focusing beam having a different focusing ratio with respect to the vertical axis direction.

Hereinafter, a variation of the cylindrical focusing lens in the gas measuring optical system according to the embodiment of the present invention will be described with reference to FIGS. 6 to 8. FIG. 6 to 8 are views showing a modification of the cylindrical focusing optical lens in the gas measuring optical system according to the embodiment of the present invention.

The cylindrical condensing optical lens shown in Fig. 6 is a cylindrical convex lens having one surface that faces the infrared light source unit 10 in a plan view, and a surface opposite to the one surface has a convex shape in the optical axis direction (z axis direction). This cylindrical condensing optical lens whose one surface is convex in the direction of the optical axis forms the converging tangential light in the form of focusing only in one direction shown in Fig. 5 (b).

The cylindrical condensing optical lens shown in Fig. 7 has a planar surface facing the infrared light source portion 10 and a surface on the opposite side of one surface with respect to the optical axial direction (z-axis direction) Is a cylindrical convex lens having a radius. Such cylindrical convex lenses form elliptical focusing light beams having different degrees of convergence in the vertical direction different from the one direction shown in Fig. 5 (c).

The cylindrical condensing optical lens shown in Fig. 8 has a cylindrical shape having a different radius of curvature in the other axial direction perpendicular to the optical axis direction (z-axis direction) on one surface facing the infrared light source unit 10 and on the opposite surface on one surface It is a convex lens. Such cylindrical convex lenses form elliptical focusing light beams having different degrees of convergence in the vertical direction different from the one direction shown in Fig. 5 (c), like the cylindrical convex lenses shown in Fig.

The embodiments of the present invention described above are not only implemented by the apparatus and method but may be implemented through a program for realizing the function corresponding to the configuration of the embodiment of the present invention or a recording medium on which the program is recorded, The embodiments can be easily implemented by those skilled in the art from the description of the embodiments described above.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It belongs to the scope of right.

10: Infrared light source part 20: Parallel optical lens
30: gas cell 40: cylindrical condensing optical lens
50: measuring light measuring unit 60: reference light measuring unit
51: Measuring light filter 52: Measuring light sensor
61: reference light filter 62: reference light sensor

Claims (7)

An infrared light source unit for emitting a first infrared ray of a specific wavelength band,
A parallel optical lens for converting the infrared rays into parallel rays,
A gas cell in which an infrared ray transmitting window for transmitting the parallel light is formed,
A cylindrical condensing optical lens for converting the parallel light that has passed through the gas cell into focused different light,
A measuring light measuring unit positioned within the range of the focused other-focused light and measuring the measuring light, and
And a reference light measuring unit which is located within the range of the focused heterochromatic light and which is arranged in a direction perpendicular to the optical axis of the first infrared ray with respect to the measuring light measuring unit and measures the reference light,
Wherein the infrared light source unit, the parallel light lens, the gas cell, and the cylindrical condensing optical lens are located on the optical axis of the first infrared ray,
The collimated tungsten light is elliptical light having the same length in a first axis direction perpendicular to the optical axis as compared with the parallel light and having a shorter length in the second axis direction perpendicular to the optical axis and the first axis, Wherein the optical axis is a elliptical light having a length in a first axis direction perpendicular to the optical axis and a length in a second axis direction perpendicular to the optical axis and the first axis. The method of claim 1,
Wherein the cylindrical focusing optical lens has a cylindrical convex lens having a flat surface facing the infrared light source portion and a surface opposite to the one surface having a convex shape in the optical axis direction of the first infrared ray and a cylindrical convex lens having a surface facing the infrared light source portion A cylindrical convex lens having a plane and an opposite surface on one side having different curvature radii with respect to a direction of an optical axis of the first infrared ray and a direction of a vertical axis different from one axial direction; Is a cylindrical convex lens having different radii of curvature in different axial directions perpendicular to each other with respect to the optical axis direction of the first infrared ray. delete 3. The method according to claim 1 or 2,
Wherein the parallel optical lens has a spherical or aspherical rotationally symmetric convex lens shape or a hemispherical convex lens shape. 5. The method of claim 4,
Wherein the material of the parallel optical lens and the cylindrical focusing optical lens is one of silicon (Si), germanium (Ge), CaF2, and sapphire (Al2O3) that can be used in the infrared band. The method of claim 5,
Wherein when the material of the parallel optical lens and the cylindrical condensing optical lens is silicon, an anti-reflective coating is applied to the surfaces of the parallel optical lens and the cylindrical condensing optical lens to increase the transmittance. The method of claim 1,
Wherein the measurement light sensor included in the measurement light measurement unit and the reference light sensor included in the reference light measurement unit are formed on one circuit board.

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