KR101872740B1 - Double supported Lamellar grating mirror structure and its application for the remote gas sensing Lamellar grating type FTIR - Google Patents

Double supported Lamellar grating mirror structure and its application for the remote gas sensing Lamellar grating type FTIR Download PDF

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Publication number
KR101872740B1
KR101872740B1 KR1020170023671A KR20170023671A KR101872740B1 KR 101872740 B1 KR101872740 B1 KR 101872740B1 KR 1020170023671 A KR1020170023671 A KR 1020170023671A KR 20170023671 A KR20170023671 A KR 20170023671A KR 101872740 B1 KR101872740 B1 KR 101872740B1
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South Korea
Prior art keywords
mirror
driving
support
lamellar grating
mirrors
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KR1020170023671A
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Korean (ko)
Inventor
강영일
김인철
김성규
박도현
배효욱
강민재
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국방과학연구소
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
    • G01J3/02—Details
    • G01J3/10—Arrangements of light sources specially adapted for spectrometry or colorimetry
    • G01J3/108—Arrangements of light sources specially adapted for spectrometry or colorimetry for measurement in the infrared range
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J9/00—Measuring optical phase difference; Determining degree of coherence; Measuring optical wavelength
    • G01J9/02—Measuring optical phase difference; Determining degree of coherence; Measuring optical wavelength by interferometric methods
    • G01J2009/0234—Measurement of the fringe pattern
    • G01J2009/0238—Measurement of the fringe pattern the pattern being processed optically, e.g. by Fourier transformation

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  • Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • General Physics & Mathematics (AREA)
  • Spectrometry And Color Measurement (AREA)

Abstract

The present invention relates to a Fourier-transform infrared spectroscope (FTIR) of a lamellar grating type, capable of remotely detecting gas components and, more specifically, to a structure of a mirror for an interferometer of a lamellar grating type, which is a core component of the FTIR. A remote FTIR includes: a lamellar grating mirror including a fixed mirror and a driving mirror arranged to be adjacent to each other to reflect infrared rays generated by an infrared generator; a supporting frame forming an inner space to accommodate the lamellar grating mirror; a mirror supporting unit formed to support both ends of the driving mirror; and a driving arm protruding from at least an area of the mirror supporting unit to connect the supporting frame and the mirror supporting unit, and combined with the supporting frame. The present invention may increase flatness compared with an existing mirror by applying a mirror structure supporting both ends of the driving mirror and supporting the bottom surface of the fixing mirror.

Description

TECHNICAL FIELD [0001] The present invention relates to a mirror structure for a lamellar grating having both end supports for a remote Fourier transform infrared spectroscope, and a mirror structure for a lamellar grating type FTIR,

FIELD OF THE INVENTION The present invention relates to a Lamellar grating type Fourier transform infrared spectroscope capable of detecting a gas component remotely, and more particularly, to a mirror structure for a interferometer in the form of a lamellar grating, which is an essential part of a Fourier transform infrared spectroscope.

  The Fourier transform infrared spectroscope is generally used for analyzing infrared rays according to their wavelengths. The infrared spectroscopy is used to obtain the infrared light spectrum by Fourier transforming the interference fringes of the infrared light, and then analyzing the infrared light spectrum to obtain compositional data and chemical structure data between the materials.

The Lamellar grating type infrared spectroscope (FTIR) includes a lamellar grating mirror composed of a driving mirror and a fixed mirror, and infrared rays generated from the infrared ray generating source are reflected to the driving mirror and the fixed mirror, respectively. The infrared rays are respectively reflected on the lamellar grating mirror, collected through an appropriate optical system, and then condensed by a specific measurement sensor.

At this time, the infrared rays can be divided into infrared rays reflected on the fixed mirror and infrared rays reflected on the driving mirror, and they have a path difference according to the driving of the driving mirror.

Therefore, an interference signal is measured in the measurement sensor, and when the signal is subjected to a Fourier transform, a desired infrared spectrum is obtained, and the type of gas of the infrared ray emission source can be determined from the interference spectrum.

Meanwhile, in order to measure infrared interference characteristics remotely from such a long distance as possible, the interferometer of the lamellar grating structure requires a large effective reflection area of the mirror capable of passing the light amount, so that the amount of infrared light that can pass therethrough increases. However, in order to increase the size of the reflection mirror, it is necessary to secure the flatness required for the mirror, that is, the flatness.

Therefore, in order to improve the flatness, the present invention proposes a lamellar grating mirror structure of a remote Fourier transform infrared spectroscope that is formed to support both ends of a driving mirror and a lower surface of a fixed mirror instead of a conventional single supporting mirror structure.

The object of the present invention is to provide a mirror structure capable of improving the flatness of each mirror surface in spite of the residual stress caused by thermal deformation when a large aperture mirror required for telemetry is manufactured using a MEMS process. have.

According to an aspect of the present invention, there is provided a method of manufacturing a lamellar grating mirror, the method comprising: providing a lamellar grating mirror including a fixed mirror and a driving mirror disposed adjacent to each other to reflect infrared rays generated from an infrared ray generating source; A mirror supporting portion formed to support both ends of the driving mirror, and a driving arm projecting from at least one region of the mirror supporting portion to connect the supporting frame and the mirror supporting portion and coupled to the supporting frame, A Fourier transform infrared spectroscope can be provided.

In one embodiment of the present invention, the mirror support portion further includes a central portion formed to support a center portion of the drive mirror, and an outer frame portion formed to correspond to an outer periphery of the drive mirror to support an end portion of the drive mirror, One side of the fixed mirror may be fixed to the support frame.

In one embodiment of the present invention, the driving arm may be formed of first to fourth driving arms which are formed to protrude from the outer frame in one direction and are bent in the other direction from one direction to be coupled to the supporting frame .

The present invention can obtain the following effects by the above-described embodiment, the constitution described below, and the combination and use relationship.

The present invention can improve the flatness of an existing mirror by applying a mirror structure supporting both ends of the driving mirror and supporting the lower surface of the fixing mirror.

Further, by improving the flatness of the present invention, it is possible to develop a Fourier transform infrared spectroscope having a lamellar grating structure with improved telemetry performance.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a conceptual diagram illustrating the FTIR measurement principle of a lamellar grating structure. FIG.
Fig. 2 is a conceptual diagram illustrating a single support geometry mirror structure of the prior art.
Fig. 3 is an explanatory diagram of the test result of the flatness problem of the prior art.
4 is a conceptual diagram of micrograting of both end support structures of the present invention.
5 is a conceptual view for explaining the principle of improving flatness of both end support structures of the present invention.

Hereinafter, preferred embodiments of a mirror structure for a lamellar grating having both end support structures according to the present invention will be described in detail with reference to the accompanying drawings. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. Throughout the specification, when an element is referred to as "including" an element, it is understood that the element may include other elements as well as other elements, The terms "part," " module, "and the like denote a unit for processing at least one function or operation, which may be implemented as hardware or software or a combination of hardware and software.

In the interferometer of the lamellar grating structure, the larger the effective reflection area of the mirror capable of passing the light amount, the easier it is to remotely measure the infrared interference characteristic. In order to increase the size of the reflective mirror, the flatness required for the mirror needs to be improved.

Therefore, the present invention proposes a mirror structure in which the flatness of the mirror surface of the interferometer of the lamellar grating structure can be improved despite the residual stress generated in driving the driving mirror.

First, a structure of a general Lamellar grating type Fourier transform infrared spectroscope (hereinafter, referred to as an infrared spectroscope) will be described before explaining the mirror structure of the remote Fourier transform infrared spectroscope 100. FIG.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a conceptual diagram illustrating the FTIR measurement principle of a lamellar grating structure. FIG.

Referring to FIG. 1 (a), the lamellar grating mirror 30 is composed of a plurality of driving mirrors 3 separated from each other and spaced apart from each other, and fixed mirrors 4 separated from each other and arranged apart from each other. The infrared rays 2 generated in the infrared ray generating source 1 are reflected to the rammel grating mirror 30 composed of the driving mirrors 3 and the fixed mirrors 4, respectively. The infrared rays 2 are respectively reflected on the lamellar grating mirror 30 and collected through an appropriate optical system and condensed by a measurement sensor 5 disposed adjacent to the lamellar grating mirror 30. [

The infrared ray 2 is incident on the driving mirrors 3 and the infrared ray 2a reflected by the fixing mirrors 4 in accordance with driving in a direction 6 perpendicular to the mirror surface of the driving mirrors 3. [ And the infrared ray 2b reflected by the infrared ray 2b. At this time, the infrared rays 2b reflected by the driving mirrors 3 have a path difference with respect to the infrared rays 2a reflected by the fixed mirrors 4.

Accordingly, an interference signal is measured in the measurement sensor 5, and when the signal is subjected to Fourier transform, a desired infrared spectrum is obtained, and the type of gas of the infrared ray emission source can be determined therefrom.

Referring to FIG. 1 (b), the driving mirrors 3 and the fixed mirrors 4 are spaced apart from each other. More specifically, the fixed mirrors 3 4), and the driving mirrors 3 may be disposed in the spacing space of the stationary mirrors 4. At this time, since the fixed mirrors 4 and the driving mirrors 3 must perform a movement having a relative displacement, the driving mirrors 3 and the fixed mirrors 4 can not contact each other, (7).

 Fig. 2 is a conceptual diagram illustrating a single support geometry mirror structure of the prior art. FIG. 3 is an explanatory diagram of the test result of the conventional flatness problem generation.

The lamellar grating mirrors 30 may be provided in a plurality of ways, and may be arranged to face each other.

Referring to FIG. 2 (a), the lamellar grating mirror 30 may include driving mirrors 3 disposed on the left and right sides, respectively. One end of each of the left driving mirror 3a and the right driving mirror 3b may be attached and fixed to the central supporting portion 11. [

The central support part 11 is supported by a support frame fixing part 10 disposed on the outer periphery of the lamellar grating mirror 30 through a driving arm 9. The driving mirrors 3 fixed to the supporting frame fixing portion 10 through the driving arm 9 are driven in a direction perpendicular to the mirror surface through suitable driving means, Have a contrast path difference.

Further, the left and right driving mirrors 3 are alternately divided into a plurality of units, and alternately arranged so as to be disposed between the fixed mirrors 4 divided into a plurality of units.

2 (a) and 2 (b), one end of each of the plurality of driving mirrors 3 may be fixed to the center support portion 11, but may be formed at a position opposite to the one end The mirror end 12 does not have a structure that can be fixed separately.

More specifically, the fixed mirror 4 must pass through the end portion 12 of the driving mirror and be connected to a separate external supporting frame. At this time, the driving of the driving mirrors 3, It is impossible to separate the connection portions between the support frames. Therefore, in this structure, the driving mirrors 3 have a single support shape in which the center portion is fixed but the outer portion is not fixable.

On the other hand, since the driving and fixing mirrors 3 and 4 must be extremely flat with respect to the incident and reflected light beams, the phases of the mirror reflection beams are influenced only by the distances between the driven mirrors and the fixed mirrors. The desired spectrum distribution can be obtained.

However, if the respective surfaces of the driving mirrors 3 are bent by themselves, a path difference is generated between the reflected mirrors of the driving mirrors 3 separately from the driving distance of the driving mirrors 3. Also, in the fixed mirrors 4, when the mirror surfaces are bent by themselves, the reflected lights of the fixed mirrors 4 also have an additional path difference.

That is, if the two mirrors (3, 4) have self-warping, the path difference between the fixed and driven mirrors (3, 4) Therefore, each mirror (3, 4) has its own mirror surface to be warped beyond a certain reference. If the force of the mirror itself is evaluated as a deviation in height difference per unit length, that is, a flatness, It should have a smaller flatness.

For example, in the case of medium infrared rays, if the measured wavelength band is 7 mm to 13 mm, the flatness should have a flatness of 1/10 of the minimum wavelength of 7 mm, that is, 0.7 mm or less.

However, most of the mirror fabrication process involves residual stress due to various causes such as thermal deformation during the MEMS process used for thin mirror surfaces and various coating layers (eg, silicon oxide, metal thin films, etc.) .

2 (c), in the case of the fixing mirrors 3 of a single supporting structure in which only one end is fixed to the central supporting portion 11 and the other end 12 is freely deformable, Deforms more than the flatness allowed by the end surface 12 'which is easy to deform with respect to the surface 11'. This is because the stationary mirrors 4 have a single support structure, so that many deformations occur for the same reason.

Referring to FIG. 3, actual examples of the conventional single-support driving mirrors are fabricated through a MEMS process, and examples of the measurement results of bending occurrence due to residual stress are shown.

The degree of warpage 13 is significantly out of the flatness of 0.7 mm or less, which is required to be about 19 mm. For the same source of residual stress, the occurrence of such deflection increases as the effective mirror area for increasing the amount of light increases, so it is necessary to solve this flatness problem in order to manufacture a large diameter mirror required remotely.

FIG. 4 is a view showing a mirror structure of a remote Fourier transform infrared spectroscope 100 according to an embodiment of the present invention, and FIG. 5 is a view of FIG. 4 viewed from another direction.

4A and 4B, the remote Fourier transform infrared spectroscope 100 includes a fixed mirror 14 and a driving mirror 15 disposed adjacent to each other to reflect infrared rays generated from an infrared ray generating source, A support frame 17 forming an internal space for accommodating the lamellar grating mirror, mirror supports 18 and 19 formed to support both ends of the drive mirror 15, and a support frame 17 (Not shown).

In the remote Fourier transform infrared spectroscope 100 according to an embodiment of the present invention, the support frame 17 has a rectangular parallelepiped shape, and has a recessed portion having a predetermined thickness inwardly to receive the lamellar grating mirror on one surface. . However, it is not limited to the size and shape disclosed in the present invention, provided that the support frame 17 is sized and shaped to accommodate the lamellar grating mirror.

The mirror supports 18 and 19 are formed to correspond to the outer periphery of the driving mirror 15 so as to support the end portion of the driving mirror 15 and a central portion 18 formed to support the central portion of the driving mirror 15. [ And an outer frame portion 19 formed on the outer circumferential surface.

One end of the driving mirror 15 is connected to the central portion 18 and the other end of the driving mirror 15 is connected to the outer frame portion 19 so that both ends of the driving mirror 15 are simultaneously supported . The driving mirror 15, which is supported at both ends thereof, is mounted and fixed to the support frame 17 through the driving arm 16.

More specifically, the drive arm 16 may protrude from at least one area of the mirror support 18, 19 to connect the support frame 17 and the mirror support 18, 19.

The driving arm 16 may be formed of a plurality of driving arms which are formed to protrude in one direction from the outer frame 19 and are bent in the other direction from the one direction and coupled to the supporting frame 17. The remote Fourier transform infrared spectroscope 100 according to an embodiment of the present invention is configured to include four driving arms.

On the other hand, one side of the fixed mirror 14 may be attached to the support frame 17 and fixed thereto. Here, one surface refers to the lower surface of the fixed mirror 14, and the lower surface corresponds to the surface directly contacting the support frame 17. [

5, it can be seen that both ends of the driving mirror 15 are supported at both ends by the central portion 18 and the outer frame portion 19, respectively. Such a both-end support structure is formed by residual stress caused by thermal deformation Deformation of the driving mirrors 15 'can be suppressed relatively by the support of both ends 18', 19 ', which are superior in rigidity to the conventional single support mentioned above.

As a result of measuring the flatness of the actual driving mirrors through the MEMS process, the measured flatness was improved to about 0.5mm compared to the existing 17mm, and it was realized within the desired target of 0.6mm.

Therefore, instead of the existing single support structure, the both end support structure of the present invention is effective in improving the flatness. The both ends support structures are constructed such that the driving mirrors 15 are doubly supported at both ends by the central portion 18 and the outer frame portion 19 and the fixing mirrors 14 are supported by the supporting frame 17 The same effect can be obtained in any type of structure that is fixed to the substrate.

That is, the present invention can improve the flatness of the conventional mirror by applying a mirror structure supporting both ends of the driving mirror 15 and supporting the lower surface of the fixed mirror 14.

Further, by improving the flatness of the present invention, it is possible to develop a Fourier transform infrared spectroscope having a lamellar grating structure with improved telemetry performance.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, Should be interpreted as belonging to the scope.

Claims (3)

A lamellar grating mirror including a fixed mirror and a driven mirror disposed adjacent to each other so as to reflect infrared rays generated from an infrared ray generating source;
A support frame defining an interior space to receive the lamellar grating mirror;
A mirror support configured to support both ends of the driving mirror; And
And a driving arm protruding from at least one area of the mirror support and coupled to the support frame to connect the support frame and the mirror support,
The mirror support portion
A center portion formed to support a center portion of the driving mirror; And
And an outer frame portion formed to correspond to an outer periphery of the drive mirror to support an end portion of the drive mirror,
Wherein one end of the driving mirror is connected to the center portion and the other end of the driving mirror is connected to the outer frame portion so that one end and the other end of the driving mirror are simultaneously supported. The method according to claim 1,
Wherein the fixed mirror comprises:
And one side is attached and fixed to the support frame. ≪ RTI ID = 0.0 > 11. < / RTI > The method according to claim 1,
The drive arm,
And first to fourth driving arms which are formed to protrude from the outer frame in one direction and are bent in the other direction from the first direction to be coupled to the support frame.
KR1020170023671A 2017-02-22 2017-02-22 Double supported Lamellar grating mirror structure and its application for the remote gas sensing Lamellar grating type FTIR KR101872740B1 (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20070146720A1 (en) * 2005-12-23 2007-06-28 Honeywell International Inc. Spectrometer method and apparatus for near infrared to terahertz wavelengths
US20070159635A1 (en) * 2005-12-23 2007-07-12 Fraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung E.V. Fourier transform spectrometer
US20110181885A1 (en) * 2010-01-22 2011-07-28 Irvine Sensors Corporation Large Displacement Micro-Lamellar Grating Interferometer
US20120170024A1 (en) * 2009-09-22 2012-07-05 Medhat Azzazy Long Range Acquisition and Tracking SWIR Sensor System Comprising Micro-Lamellar Spectrometer

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20070146720A1 (en) * 2005-12-23 2007-06-28 Honeywell International Inc. Spectrometer method and apparatus for near infrared to terahertz wavelengths
US20070159635A1 (en) * 2005-12-23 2007-07-12 Fraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung E.V. Fourier transform spectrometer
US20120170024A1 (en) * 2009-09-22 2012-07-05 Medhat Azzazy Long Range Acquisition and Tracking SWIR Sensor System Comprising Micro-Lamellar Spectrometer
US20110181885A1 (en) * 2010-01-22 2011-07-28 Irvine Sensors Corporation Large Displacement Micro-Lamellar Grating Interferometer

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