JP2011145233A - Spectroscopic device - Google Patents

Abstract

Disclosed is a spectroscopic device capable of simultaneously measuring two-dimensionally the spectral distribution of measurement light from a sample.
An optical system including an incident pinhole array arranged in a grid, a diffraction grating that wavelength-disperses light incident from the plurality of pinholes, and light emitted from the optical system is received. And the optical system includes at least one of the two directions which are the arrangement directions of the incident pinhole array 11, the wavelength dispersion direction of the diffraction grating 13, and the pixel arrangement direction of the planar light receiving element 15 for receiving outgoing light. Are arranged at an angle so as not to be parallel or perpendicular.
[Selection] Figure 2

Description

  The present invention relates to a spectroscopic device, and more specifically to a spectroscopic device using a two-dimensional multi-channel photodetection element (referred to as an array element) such as a CCD as a photodetection means.

  As is well known, a so-called polychromator using an array element is a spectroscopic device that detects light that is diffracted according to a wavelength with an array element spatially arranged instead of rotating a diffraction grating.

  FIG. 1 is a main part configuration diagram showing an example of a polychromator generally used conventionally. In the figure, light incident from the slit 1 is converted into a parallel light beam by a collimating mirror 2 and enters a dispersive element (here, a diffraction grating) 3. The light exiting the diffraction grating 3 is focused by the focusing mirror 4 and irradiated onto the array element 5. In this case, if the diffraction grating is fixed at a constant angle, the diffraction angle changes according to the wavelength of the incident light, and the position of the light spot that hits the array element 5 changes (moves). Therefore, the wavelength of incident light can be known from the position of the light spot. Basically, as described above, incident light is introduced from the slit, and the light separated by the diffraction element in the width direction of the slit is received by the detection element. On the other hand, an optical system is arranged on the entrance slit so that a one-dimensional image of the measurement object is projected in the longitudinal direction of the slit, and the spectrum is improved so that the one-dimensional spatial distribution of the wavelength distribution of the measurement object can be measured simultaneously. There is also a vessel. Based on this method, measuring the two-dimensional spatial distribution of the wavelength distribution of the measurement object is realized by scanning the one-dimensional spatial distribution measurement in the direction of another spatial axis (for example, see Non-Patent Document 1). ). The scanning is mechanically performed in the existing apparatus, and it takes about 1 second because it is commercialized.

Eva Japan Co., Ltd., Hyperspectral Camera HSC1701 catalog

  However, the above-described apparatus requires a finite time for scanning due to the mechanism, and therefore, the two-dimensional spatial distribution of the wavelength distribution of the measurement target cannot be measured simultaneously. In the last scanning part, the measurement time shifts and gives an inaccurate measurement result.

  The present invention has been made in view of the above-described background. The object of the present invention is to solve the above-described problems and simultaneously measure the two-dimensional spatial distribution of the wavelength distribution of the measurement light from the measurement target. A spectroscopic device is provided to enable measurement of high-speed fluctuation phenomena.

  In order to achieve the above-described object, in the spectroscopic device according to the present invention, a plurality of incident apertures arranged in a lattice pattern, and an optical system including a dispersion element that wavelength-disperses light incident from the plurality of incident apertures; A light detecting means for receiving light emitted from the optical system, wherein the light detecting means has a light receiving surface in a two-dimensional plane, and the optical system has at least one of two directions which are the arrangement directions of the incident ports. The dispersive element is disposed and configured so as to have an angle so as not to be parallel or perpendicular to the wavelength dispersion direction of the dispersive element (claim 1). The incident port may be any one of a pinhole, a slit, an output end of an optical fiber, and an output end of a tapered glass.

  The spectroscopic device according to the present invention can simultaneously measure the two-dimensional spatial distribution of the wavelength distribution of the measurement light from the measurement target, and can also cope with high-speed time series measurement.

It is a figure explaining a prior art. It is a figure which shows one Embodiment of the spectroscopic device which concerns on this invention. It is an example of the wavelength separation optical recording pixel arrangement | positioning on the two-dimensional photodetection element 15 of the spectroscopic device which concerns on this invention.

  Examples of the best mode for carrying out the present invention will be described below.

  FIG. 2 shows a preferred embodiment of the spectroscopic device according to the present invention. As shown in the figure, measurement light is introduced so that a two-dimensional image of the measurement object is formed on the surface of the incident pinhole array 11 arranged in a lattice pattern. Light incident from each pinhole is converted into a parallel light beam by the collimating mirror 12 and enters the dispersive element (here, diffraction grating) 13. The wavelength-dispersed light is focused by a focusing mirror 14 and imaged at a predetermined position of the two-dimensional photodetecting element 15. Here, if the arrangement direction of the incident pinhole array 11 coincides with the chromatic dispersion direction of the diffraction grating, the image on the two-dimensional photodetecting element 15 is chromatic dispersion at other points adjacent to the chromatic dispersion direction of the diffraction grating. Immediately overlaps with the image and no effective measurement is possible.

  Therefore, in the present invention, the two-dimensional arrangement is made by arranging at an angle so that at least one of the two directions which are the arrangement directions of the incident pinhole array 11 and the wavelength dispersion direction of the diffraction grating are not parallel or orthogonal. For example, an image on the light detection element 15 is formed as shown in FIG. 3, and light obtained by wavelength-separating light from a certain measurement point is converted into light obtained by wavelength-separating light from other adjacent points and the two-dimensional light detection element 15. It is possible to receive light so as not to overlap with each other, and to simultaneously record the two-dimensional spatial distribution of the wavelength distribution of the measurement light from the measurement object. In FIG. 3, (1, 1), (2, 1),..., (M, n) are the row number m and the column number n of the pinhole of the corresponding incident pinhole array 11.

  The inclination angle between one of the two axes of the grating array of the incident pinhole array 11 and the wavelength dispersion direction of the diffraction grating is the number of incident pinholes, the number of pixels of the two-dimensional photodetecting element 15, and the wavelength resolution of each measurement point. Can be set in various ways according to measurement requirements.

  By applying a device capable of continuous time series measurement (typically a two-dimensional multi-channel photodetection device such as a CCD) to the two-dimensional light detection element 15 of the spectroscopic device according to the present invention, time series measurement is also possible. It becomes. Since the two-dimensional spatial distribution of the wavelength distribution of the measurement light can be recorded in one frame on the two-dimensional photodetector 15 of the spectroscopic device according to the present invention, the time resolution at that time is the highest frame of the two-dimensional photodetector 15. It depends only on the rate.

  By rotating the entire optical system along the optical axis of the entrance, the orientation of the entire array of measurement points can be set arbitrarily. Further, the two-dimensional arrangement form of the measurement points is set by the lattice shape of the incident pinhole array 11, and can be arbitrarily set within a range where the measurement light does not overlap on the two-dimensional photodetecting element 15, and the flexibility of the lattice shape is high.

  Also according to the present invention, since the number of pixels allocated in the wavelength separation direction on the two-dimensional photodetector 15 for each measurement point is finite, when the wavelength distribution of the measurement light is wide, the lights at adjacent measurement points are mixed. However, the characteristics of the dispersion element are such that the detectable wavelength range of the two-dimensional photodetecting element 15 falls within the wavelength range recordable by the detecting element pixel assigned to each measurement point. Or by limiting the wavelength range of incident light with an optical bandpass filter in advance.

  In this apparatus, a dead zone (for example, a light non-passing region between the pinholes of the incident pinhole array 11 in FIG. 2) is generated between the measurement points. This can be dealt with by appropriately arranging in place of the two-dimensional pinhole array 11 or in front of the incident two-dimensional pinhole array 11. In addition to the above-described diffraction grating, a prism can also be used as the dispersion element.

  For example, the wavelength distribution of light that cannot be seen by the eyes can be imaged by dividing and combining the wavelength regions in the infrared and ultraviolet regions. In addition, by measuring color differences and changes that cannot be discerned by the eyes, non-contact and non-destructive inspection of machines, electronic circuits, biological tissues, foods, structures, fluids, flames, etc. is possible. Furthermore, these high-speed fluctuation phenomena can also be observed.

1 slit 2 collimating mirror 3 dispersive element (here diffraction grating)
4 Focusing mirror 5 Two-dimensional multi-channel photodetector 11 Pinhole arrangement 12 Collimating mirror 13 Dispersion element (here, diffraction grating)
14 Focusing mirror 15 2D multi-channel photodetector

Claims (2)

  An optical system including a plurality of incident apertures arranged in a lattice shape, a dispersion element that wavelength-disperses light incident from the plurality of incident apertures, and a light detection unit that receives light emitted from the optical system; The light detecting means has a light receiving surface that is a two-dimensional plane, and the optical system is configured so that at least one of the two directions that are the arrangement directions of the entrance apertures and the wavelength dispersion direction of the dispersive element are not parallel or perpendicular to each other. A spectroscopic device characterized by being arranged with an angle.   The spectroscopic apparatus according to claim 1, wherein the incident port is any one of a pinhole, a slit, an output end of an optical fiber, and an output end of a tapered glass.