JPS63315922A - Spectral photometric device - Google Patents

Abstract

PURPOSE:To eliminate a filter switching part in a single detector and to perform spectral photometry continuously over a wide range by detecting diffracted light different in diffraction order by plural array type detectors according to a wavelength range. CONSTITUTION:Incident light 1 which is incident on an incidence slit 2 is separated and diffracted by a concave surface diffraction grating 3. This diffracted light is image-formed by wavelength at a position shown by a spectral image formation position curve 20 through the image formation of the concave surface diffraction grating 3. Light of 600nm-900nm wavelength is passed through a high-order light cut filter 5 which cuts light of <=600nm and detected by an array detector 4 at the position of diffracted light of (+1)th order. Diffracted light of (-2)th order in a 340nm-600nm wavelength range to the diffracted light 13 of (-1)th order is detected directly by the array detector 4.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a spectroscopic optical device, particularly for array type detection)! :(This relates to a spectroscopy 8+11 optical device suitable for use in a spectroscopy 11111 optical device.

[Conventional technology]

Conventional devices of this type have a high-order light cut at a predetermined position in front of the detector to remove high-order spectral images formed on an array type detector (solid-state image pickup device), as described in Japanese Patent Application Laid-Open No. 59-131123. By installing a filter, the original diffracted light and the higher-order diffracted light can be detected separately.

However, this method does not take into consideration the disturbance of the spectral image due to refraction and scattering of light rays at the boundary between the portion where the filter is attached and the portion where the filter is not attached.

Spectroscopy Research Vol. 32 No. 3 (1983) No. 173
The document titled ``Development of Mechanically Scored Sorption-Corrected Concave Diffraction Grating for Flat-Field Polychromators'' by Toshiaki Kita on pages 182 to 182 forms the theoretical background of the present invention. No consideration has been given to a spectroscopy d11 optical device covering a wide wavelength range in which the wavelengths overlap.

The optical arrangement according to the above-mentioned prior art is shown in FIG. 3. Incoming light 71 that passes through 72 into the thin-input sulin 1 is dispersed and diffracted by a concave diffraction grating 74, and detected by an array type detector 76. At this time, the high-order diffracted light superimposed on the diffracted light was removed by setting the high-order light cut filter 77 at a predetermined position.

[Problem that the invention seeks to solve]

In the above-mentioned prior art, no consideration was given to the case of detecting a continuous spectrum, and there was a problem in that a step difference occurred in the spectrum at the end of the high-order light cut filter. In addition, reports on spectroscopic research disclose details regarding the spectral imaging position, but the wavelength range is narrow and the spectral d for the purpose of obtaining continuous spectra over a wide range.
It cannot be used as an 111 optical device.

The purpose of the present invention is to use a plurality of array-type detectors and independently set a high-order light cut filter for each detector, thereby eliminating the filter switching section within the m-detector and achieving continuous spectroscopy over a wide range. An object of the present invention is to provide a spectrophotometric device capable of photometry.

[Means for solving problems]

The second object is achieved by using a configuration in which a plurality of array type detectors detect diffracted light having different orders of diffraction depending on the wavelength range.

[Effect]

In general, high-order diffracted lights of the same gender will overlap in a wide wavelength range, but diffracted lights of opposite signs will appear in separate positions with the O-order diffracted light as a boundary. Therefore, different filters can be installed independently, and a continuous spectrum can be obtained by eliminating the need for a filter switching section inside the detector.

〔Example〕

The present invention will be described in detail below with reference to the embodiment shown in FIG. 1 and FIG. 2.

FIG. 1 is an optical system diagram showing an embodiment of the spectrophotometric device of the present invention. In FIG. 1, 1 is an incident light, 2 is an entrance slit, and 3 is a concave diffraction grating. The incident light 1 entering the entrance slit 2 is separated and diffracted by the concave diffraction grating 3. This diffracted light is imaged at a position shown by a spectral imaging position curve 20 for each wavelength due to the imaging property of the concave diffraction grating 3.

With the O-order diffracted light 12 as a boundary, the 10th-order diffracted light and the partial several-order diffracted light form images at different positions. Currently, the wavelength range is 340
Consider a spectrophotometer such as nm to 900 nm. In this wavelength range, from 340nm to 450nm
The +2nd order diffracted light of +1 of 900nm from 680nI11
It is cursed by the position where it overlaps with the next diffracted light. Therefore, 600nm
The light with a wavelength of 900 nm from
It is detected by the array detector 4 at the position.

1st order diffracted light 1 in the wavelength range from 340nm to 600nm
The primary and secondary diffracted light for 3 is from 170 nm to 300 nm.
The wavelengths of light overlap, but since a normal incandescent lamp does not have energy in this region, it is directly received by the array detector 4.

With such an arrangement, it is possible to eliminate a filter switching section within one array type detector 4, and it is possible to obtain a continuous spectrum that eliminates optical discontinuity at the ends of the filter.

FIG. 2 is an enlarged schematic diagram of a concave diffraction grating. According to the embodiment of the present invention, since the array type detector 4 is used independently depending on the wavelength range, a +1st order diffracted light blaze 30 and a 11st order diffracted light blaze 30 are used in each diffracted light direction as shown in FIG. By providing 31 independently, blazed diffracted light can be obtained from each. At this time, if the area of the blazed surface is marked with lines so that the respective amounts of light are balanced, it is possible to obtain a spectrophotometric device in which each array type detector 4 is energy-balanced.

〔Effect of the invention〕

According to the present invention as described above, one filter can be used for one array type detector, so there is an effect that optical shock at the ends of the filter can be eliminated.

[Brief explanation of drawings]

Fig. 1 is an optical system diagram showing an embodiment of the spectrophotometric device of the present invention, Fig. 2 is an enlarged schematic diagram of a concave diffraction grating, and Fig. 3 is a bird's-eye view of a conventional spectrophotometric device. . 1...Incoming light, 2...Incoming slit, 3...Concave diffraction grating, 4...Array type detector, 5...High-order light cut filter.

Claims (1)

[Claims] 1. In a spectrophotometer comprising a concave diffraction grating, an array type detector, and a high-order light cut filter, diffracted light having different orders of diffraction depending on the wavelength range is detected by a plurality of the array type detectors. A spectrophotometric device characterized by having a configuration for detecting. 2. The spectrophotometric device according to claim 1, wherein the +1st order and -1st order are selected as the diffraction orders. 3. The concave diffraction grating has a grating surface that separates the +1st-order diffracted light and the -1st-order diffraction light.
The spectrophotometric device according to claim 1 or 2, wherein the spectrophotometer has a structure in which the lines are scored so as to blaze the next diffracted light. 4. The spectrophotometer according to claim 3, wherein the areas of the respective blazed surfaces are distributed so that the amount of diffracted light is balanced.