Dispersion control device for spectrometer

Abstract

The present invention provides a dispersion control device for a spectrometer, the device comprising: a mask filter for filtering a spectrum from the spectrometer which analyzes the spectrum of light transmitted through or reflected from an object to be measured; an imaging optical system for expanding or compressing the spectrum; and a spectrum detector for detecting the spectrum which has been expanded or compressed by the imaging optical system.

Description

Dispersion control device of spectrometer

[0001] The present invention relates to a dispersion control device for a spectrometer, and more particularly, to a dispersion control device that can expand or compress a spectral spectrum using an imaging optical system and facilitate wavelength filtering using a mask filter.

[0002]

[0003] A spectrometer is a device that can analyze brightness information according to the wavelength of light emitted from a point or line that constitutes a measurement target by using a dispersive element such as a diffraction grating or prism. Light passing through an input terminal such as a pin hole or slit installed at the input terminal of the spectrometer is dispersed in the vertical direction as it passes through the dispersive element, thereby forming brightness information according to the wavelength of each point that constitutes a single point or line on the sensor surface of a 1D or 2D camera.

[0004] Using a spectrometer like this, the spectral composition of light passing through the input terminal can be acquired from camera data. The spectral data obtained from the spectrometer can analyze the wavelength components of light incident on the input terminal. Depending on the nature of the incident light, it contains useful information for determining the composition of a substance (solid, liquid, gas), measuring the surface shape of an object, or analyzing the structure and composition of the multilayer film that constitutes the object.

[0005] [Prior Art Literature]

[0006] [Patent Document]

[0007] Patent Publication No. 10-2020-0004576

[0008]

[0009] The purpose of the present invention is to provide a dispersion control device capable of expanding or compressing a spectral spectrum formed on a sensor surface of a general spectrometer.

[0010] In addition, the present invention aims to provide a distributed control device that can perform wavelength filtering by installing a mask filter on the sensor surface of an existing spectrometer and simultaneously expand or compress a spectral spectrum.

[0011] The technical problems to be achieved in the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by a person having ordinary skill in the technical field to which the present invention belongs from the description below.

[0012]

[0013] To solve these problems, the present invention provides a distributed control device that expands or compresses a spectrum by using an imaging optical system that recognizes a spectral spectrum formed on a primary imaging surface as an object surface in an existing spectrometer having a primary imaging surface exposed without a camera on the sensor surface.

[0014] Here, the focusing optical system may include at least one focusing lens.

[0015] Additionally, the focusing optical system can expand or compress the spectral spectrum by adjusting the magnification of the focusing lens.

[0016] In addition, the imaging optical system can expand the spectral spectrum when the magnification of the imaging lens is greater than 1, and can compress the spectral spectrum when the magnification of the imaging lens is less than 1.

[0017] Additionally, the focusing optical system may include a cylindrical lens.

[0018] In addition, the dispersion control device of the spectrometer of the present invention may further include a mask filter that spatially filters some of the wavelengths of the spectral spectrum formed on the primary imaging surface and outputs them to the imaging optical system.

[0019] Here, the mask filter may include a glass substrate and a mask pattern patterned on the glass substrate.

[0020] Additionally, the mask pattern can be patterned in various shapes on the glass substrate corresponding to the position of the wavelength to be filtered.

[0021] Additionally, the mask filter may be one of a bandpass filter, a bandstop filter, and a wavelength-selective filter, depending on its shape.

[0022] Additionally, the mask filter may be one of the partial attenuation filters in addition to simply transmitting and blocking wavelength components.

[0023] Additionally, if the purpose of the distributed control device is wavelength filtering, it may be an imaging optical system of the same size (magnification = 1) rather than an expansion or compression of the spectrum.

[0024]

[0025] According to the present invention, a spectral spectrum can be expanded or compressed using an imaging optical system, and wavelength filtering can be facilitated using a mask filter.

[0026] In addition, according to the present invention, since the spectrum initially formed in an existing spectrometer can be easily expanded by the magnification of the focusing optical system, there is an advantage in that a spectrometer having high wavelength resolution can be constructed.

[0027] In addition, according to the present invention, there is an advantage in that the wavelength of incident light can be easily filtered by positioning mask filters of various shapes on the primary imaging surface.

[0028] The effects that can be obtained from the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by a person having ordinary skill in the art to which the present invention belongs from the description below.

[0029]

[0030] Figure 1 is a schematic drawing of a typical spectrometer.

[0031] FIG. 2 is a schematic diagram illustrating a distributed control device of a spectrometer according to an embodiment of the present invention.

[0032] FIG. 3 is a drawing illustrating a band-blocking filter as a mask filter according to an embodiment of the present invention.

[0033] FIG. 4 is a drawing illustrating a wavelength selective removal filter as a mask filter according to an embodiment of the present invention.

[0034] FIG. 5 is a drawing illustrating a bandpass filter as a mask filter according to an embodiment of the present invention.

[0035]

[0036] Information on the national research and development project that supported this invention is as follows.

[0037] 1. Research and Development Project Number: RS-2024-00469061

[0038] 2. Project Name: Development of a High-Speed, High-Precision Laser Detection Module for Monitoring Semiconductor Process Complex Gas and Catalytic Plasma Discharge Modules

[0039] 3. Host organization: Korea Research Institute of Standards and Science

[0040] 4. Implementing organization (joint research and development organization): Eunju Technology Co., Ltd. (Research Director: Hojae Lee)

[0041] Terms or words used in this specification and claims should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted as meanings and concepts that conform to the technical idea of ​​the present invention, based on the principle that the inventor can appropriately define the concept of the term to explain his or her own invention in the best way.

[0042] Therefore, the embodiments described in this specification and the configurations illustrated in the drawings are only the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention. Therefore, it should be understood that there may be various equivalents and modified examples that can replace them at the time of filing this application.

[0043] Hereinafter, with reference to the attached drawings, embodiments of the present invention will be described in detail so that a person having ordinary skill in the art to which the present invention pertains can easily practice the present invention.

[0044]

[0045] Figure 1 is a schematic drawing of a typical spectrometer.

[0046] As shown in Fig. 1, a typical spectrometer is configured to include a slit (10), a first lens (20), a dispersive element (30), a second lens (40), and a spectrum detector (50).

[0047] The slit (10) passes light transmitted or reflected from the object to be measured through the transmission area (10a), and the first lens (20) converts the light passing through the transmission area (10a) of the slit (10) into parallel light and emits it to the dispersion element (30).

[0048] The dispersion element (30) may be a diffraction grating or a prism, and diffracts light passing through the first lens (20), and the second lens (50) focuses light dispersed by the dispersion element (30).

[0049] The spectrum detector (50) detects the scattered light passing through the second lens (50) and displays the spectral spectrum.

[0050] Here, the spectrum detector (50) can detect the spectral spectrum and display the brightness for each wavelength on a monitor or screen.

[0051] Additionally, the spectrum detector (50) can be applied with an image sensor and a CCD camera (Charge Coupled Device Camera).

[0052] Meanwhile, the main specifications for selecting a spectrometer are dispersion and resolution. Here, dispersion is determined by the number of grating grooves, focal length, and diffraction order of the diffraction grating (30), and resolution is calculated by the product of the full width half maximum (FWHAM) of the image that appears during the lens imaging process and the dispersion of the slit gap (c).

[0053] Typically, spectrometer users require high-resolution (small resolution) spectral analysis over a wide wavelength range and spectral data filtering in specific wavelength ranges. However, there is a trade-off between wide wavelength range and high resolution due to the slit gap and the limited conditions of the detector (number of pixels and cost). That is, to obtain data over a wide wavelength range, the spectrometer must be manufactured with a large dispersion value, but a large dispersion increases the resolution value, which lowers the resolution performance. Furthermore, because high-performance spectrometers have small resolution values, the detector must have a large number of pixels to expand the wavelength range, which is expensive and limits their production.

[0054] FIG. 2 is a schematic diagram illustrating a distributed control device of a spectrometer according to an embodiment of the present invention.

[0055] The spectrometer may include a point spectrometer, a line spectrometer, and a VIPA spectrometer. Here, the point spectrometer detects the intensity value (spectrum) of light according to wavelength by a 1D detector (line detector) located on the imaging plane.

[0056] A line spectrometer disperses the spectrum of light incident through a slit in a direction perpendicular to the slit and focuses it on a 2D detector (area detector).

[0057] A VIPA spectrometer is a special configuration of a spectrometer that uses a virtual image phase array (VIPA) and a diffraction grating simultaneously, and is an ultra-high-resolution spectrometer that uses a 2D detector.

[0058] As shown in FIG. 2, the dispersion control device of a spectrometer according to an embodiment of the present invention may be configured to include a spectrometer (100), a mask filter (150), an imaging optical system (160), and a spectrum detector (170).

[0059] The spectrometer (100) may be configured to include a slit (110), a first lens (120), a dispersing element (130), and a second lens (140), and disperses light transmitted or reflected from a measurement target object.

[0060] Here, the spectrometer (100) has the same configuration as the general spectrometer described above, so a detailed description thereof will be omitted.

[0061] The mask filter (150) can filter out some of the wavelengths of the spectrum of the spectrometer (100) and output them to the imaging optical system (160).

[0062] In this way, the mask filter (150) can focus only specific wavelengths that require analysis among the wavelengths of the spectral spectrum of the spectrometer (100) onto the spectral spectrometer (170).

[0063] FIG. 3 is a drawing illustrating a center wavelength blocking filter as a mask filter according to an embodiment of the present invention, FIG. 4 is a drawing illustrating a wavelength selective removal filter as a mask filter according to an embodiment of the present invention, and FIG. 5 is a drawing illustrating a bandpass filter as a mask filter according to an embodiment of the present invention.

[0064] Referring to FIGS. 3 to 5, the mask filter (150) may be configured to include a glass substrate (151) and a mask pattern (152) formed by patterning metal using an exposure process on the glass substrate (151).

[0065] Here, the mask pattern (152) may include a mask pattern that transmits or blocks and attenuates light corresponding to the position of the wavelength to be filtered.

[0066] Additionally, the mask pattern (152) can be patterned on the glass substrate (151) corresponding to the position of the wavelength to be filtered.

[0067] For example, the mask pattern (152) can be formed by a semiconductor manufacturing process, such as depositing or etching a metal film such as chromium on a transparent glass substrate (151).

[0068] As illustrated in FIG. 3, the mask filter (150) may be a center blocking filter. In this case, the metal pattern (152) of the mask may be formed on the glass substrate (151) in a horizontal line shape, and may be formed at a position corresponding to the first wavelength band to be blocked (FIG. 3a).

[0069] A mask filter (150) like this blocks light in the first wavelength band among the wavelengths of the spectral spectrum of the spectrometer (100) and passes other wavelength bands (Fig. 3b).

[0070] As illustrated in FIG. 4, the mask filter (150) may be a wavelength selective removal filter. In this case, the mask pattern (152) may be formed on the glass substrate (151) in a horizontal line shape, and may be formed at positions corresponding to a plurality of wavelength bands to be blocked, for example, a second wavelength band and a third wavelength band (FIG. 4a).

[0071] A mask filter (150) like this blocks light in the second wavelength band and the third wavelength band among the wavelengths of the spectral spectrum of the spectrometer (100) and passes other wavelength bands (Fig. 4b).

[0072] As illustrated in Fig. 5, the mask filter (150) may be a band-pass filter. In this case, the mask pattern (152) may be formed on the glass substrate (151) in a horizontal line shape, and may be formed at positions corresponding to the fourth and fifth wavelength bands on both sides, excluding the wavelength band to be passed (Fig. 5a).

[0073] A mask filter (150) like this passes only the wavelength band between the fourth wavelength band and the fifth wavelength band among the wavelengths of the spectral spectrum of the spectrometer (100) (Fig. 5b).

[0074] The imaging optical system (160) can expand or compress the spectral spectrum that has passed through the transmission filter (150). In particular, in the case of a 2D spectrometer using a 2D detector and a dispersive element (130) being a VIPA (virtual image phase array) dispersive element, the imaging optical system including a circular 2D lens can improve the resolution while maintaining the wavelength range.

[0075] The imaging optical system (160) may include at least one imaging lens. Here, the imaging optical system (160) may be configured to include a cylindrical lens, which is a 1D imaging lens, but is not limited thereto and may also be configured to include a 2D imaging lens.

[0076] In particular, when the imaging optical system (160) is composed of a cylindrical lens, only the magnification in the spectrum direction can be adjusted (expanded and compressed), and the magnification in the slit direction has a fixed value of 1. Therefore, when implementing in an image spectrometer corresponding to a line spectrometer, a cylindrical lens is more preferable than a 2D imaging lens in which the magnifications in both the spectrum direction and the slit direction change.

[0077] The focusing optical system (160) can expand or compress the spectral spectrum by adjusting the magnification of the focusing lens.

[0078] Specifically, the focusing optical system (160) can expand the spectral spectrum when the magnification of the focusing lens is greater than 1. At this time, the dispersion value becomes smaller and the spectral spectrum can be analyzed more precisely.

[0079] On the other hand, high-resolution diffraction grating spectrometers have a disadvantage in that the wavelength range of the spectrum is limited due to overlap between diffraction orders.

[0080] However, the dispersion control device of the spectrometer according to the embodiment of the present invention has the advantage of having a relatively high wavelength resolution while eliminating interference of diffraction orders because it first spatially separates light according to wavelength in the dispersion element (130) and secondarily expands or reduces the spatially separated spectral spectrum in the imaging optical system (160).

[0081] In addition, since the dispersion control device of the spectrometer according to the embodiment of the present invention uses an imaging optical system (160) when secondarily expanding the spectral spectrum, it has the advantage of being insensitive to alignment errors compared to when expanding the spectral spectrum using only a dispersive element such as a diffraction grating, making the system configuration easy.

[0082] The focusing optical system (160) compresses the spectral spectrum when the magnification of the focusing lens is less than 1. At this time, the dispersion value increases.

[0083] Accordingly, it is possible to obtain spectral spectrum data in which the spectral spectrum is averaged.

[0084] The spectrum detector (170) can detect a spectral spectrum filtered by a wavelength filter and expanded or compressed by an imaging optical system (160).

[0085] Here, the spectrum detector (170) may be a CMOS or CCD camera as an image sensor, but is not limited thereto.

[0086] In this way, the dispersion control device of the spectrometer according to the embodiment of the present invention sets an optimal wavelength range using a wavelength filter and adjusts dispersion through the magnification of the imaging optical system.

[0087]

[0088] The detailed description above is illustrative of the present invention. In addition, the above description merely illustrates and describes preferred embodiments of the present invention, and the present invention can be used in various other combinations, modifications, and environments. That is, changes or modifications are possible within the scope of the inventive concept disclosed in this specification, the scope equivalent to the written disclosure, and / or the scope of technology or knowledge in the art. The above-described embodiments are intended to explain the best mode for carrying out the present invention, and various modifications required for specific applications and uses of the invention are also possible in other modes known in the art for utilizing other inventions such as the present invention. Therefore, the detailed description of the invention above is not intended to limit the present invention to the disclosed embodiments. Furthermore, the appended claims should be construed to include other embodiments.

Claims

1. A spectrometer that disperses light transmitted or reflected from an object to be measured; An imaging optical system for expanding or compressing the spectrum of the spectrometer; and A spectrum detector that detects the spectral spectrum expanded or compressed by the above-mentioned imaging optical system. A distributed control device for a spectrometer including a .

2. In paragraph 1, The above-mentioned optical system By adjusting the magnification of the focusing lens, the above spectral spectrum is expanded or compressed. Dispersion control device of a spectrometer.

3. In paragraph 1, The above-mentioned optical system Containing a cylindrical lens Dispersion control device of a spectrometer.

4. In paragraph 1, A mask filter that filters out some of the wavelengths of the spectral spectrum of the spectrometer and outputs them to the imaging optical system. A distributed control device of a spectrometer further comprising:

5. In paragraph 4, The above mask filter glass substrate; and A mask pattern comprising a metal patterned on the glass substrate using an exposure or etching process. Dispersion control device of a spectrometer.

6. In paragraph 5, The above mask pattern is A mask pattern that transmits or blocks and attenuates light corresponding to the position of the wavelength to be filtered. Dispersion control device of a spectrometer.

7. In paragraph 4, The above mask filter One of the bandpass filters, bandstop filters and wavelength selective removal filters. Dispersion control device of a spectrometer.

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