JPS6344189B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a densitometer, and particularly to a densitometer that combines a solid-state image sensor (detector) and a spectrometer.

For example, photodiode arrays have been developed as solid-state image detectors, but these have several advantages, such as the small size of the light-receiving elements, the ability to arrange the light-receiving elements in a straight line or in a plane, and the fast response. It has unique characteristics and is used as a densitometer detector in combination with a spectrometer.

FIG. 1 is a schematic diagram of a densitometer configured to perform well-known two-wavelength measurement using this solid-state image detector. In the figure, 1 is a white light source, 2 is a condensing lens, 3 is a sample to be measured, For example, at the sample spot developed on the TLC plate 4, the condenser lens 2
focuses the light from the light source 1 onto the spot 3. Note that in the figure, the light source 1 is arranged for transmission, but a reflection light source (not shown) may be used instead.
Or it may be additionally provided for alternative use.

The transmitted light or reflected light from sample spot 3 is
The spot 3 is imaged by the imaging lens 5 onto the entrance slit 6 of the spectrometer as an image 3'. The light from the measurement target portion of the spot image 3' is transmitted from the entrance slit 6 to a spectroscopic element (for example, a concave diffraction grating).
7 and is separated into spectra.

Slit images 6' corresponding to each wavelength separated by this diffraction grating 7 are continuously formed on the spectral image plane 8, so by placing the detector at an appropriate position on this plane 8, Photometry can be performed at any wavelength.

In this case, to perform two-wavelength photometry, for example, two detectors 9λ ₁ and 9λ ₂ are placed at desired wavelength positions on the spectral image plane 8, and to select two wavelengths, each detector is placed on the spectral image plane 8. It is only necessary to displace it in the wavelength dispersion direction (lateral direction) on the image plane 8 (this is also possible by a combination of detector displacement and rotation of the diffraction grating).

Note that the subsequent processing of the measured values by the detector will not be described since dual wavelength measurement is well known.

In the above configuration, the following problems occur. In other words, a solid-state image detector has a wiring bundle connected to the many elements that make up the detector, such as a photodiode array, so the wiring bundle is dragged each time the detector position is changed for wavelength selection. As a result, accidents such as wire breakage are likely to occur.

Further, due to limitations due to the physical size of the detectors, it is not possible to arrange two detectors in parallel at two wavelength positions closer than a certain interval, and free selection of wavelengths is not possible.

In order to overcome the above drawbacks, the present invention arranges the entrance end faces of at least a pair of optical fibers each having a slit-shaped entrance and exit end face or image guide surface so as to be freely displaceable in the wavelength dispersion direction on the spectral image plane. In addition, the above-mentioned output end face is arranged to face each light receiving surface of at least a pair of fixedly arranged solid-state image detectors.

Hereinafter, an embodiment of the present invention will be described with reference to FIG. 2. In FIG. 2, the same reference symbols as in FIG. 1 indicate the same corresponding elements as in FIG. 1, so the explanation will be omitted.

According to the invention, the solid-state image detectors 9λ ₁ , 9
λ ₂ is not placed on the spectral image plane 8 but is fixedly placed at a suitable position in the device. 10λ ₁ , 10λ ₂
are image guide type optical fibers each having a narrow slit-shaped entrance end face (image guide face) Iλ ₁ , Iλ ₂ and an exit end face Eλ ₁ , Eλ ₂ .

The incident end surfaces Iλ ₁ and Iλ ₂ almost match the height and width of the above-mentioned slit image 6', respectively, and are juxtaposed on the spectral image plane 8 so that they can each be displaced in the wavelength dispersion direction, while the exit end surfaces The end surfaces Eλ ₁ and Eλ ₂ are arranged to face the light receiving surfaces of the detectors 9λ ₁ and 9λ ₂ , respectively.

Therefore, by arranging the incident end surfaces Iλ ₁ and Iλ ₂ at the positions of the desired wavelengths λ ₁ and λ ₂ on the spectral image plane 8, respectively, light of the desired wavelengths can be guided to the detectors 9λ ₁ and 9λ ₂ . Can be done.

In this case, it is necessary to project the image on the spectral image plane 8 onto the light-receiving surfaces of the detectors 9λ ₁ and 9λ ₂ without distorting it, and for this reason, the above-mentioned image guide type optical fibers 10λ ₁ and 10λ ₂ are It is noted that the fibers (strands) constituting this optical fiber are arranged at the incident end faces Iλ ₁ , Iλ ₂ and the exit end faces Eλ ₁ , Eλ ₂ so as to occupy the same corresponding geometric positions on both end faces. is necessary.

The outputs of the detectors 9λ ₁ and 9λ ₂ are then amplified and processed by a suitable circuit or device depending on the purpose of measurement.

As described above, in the present invention, the slit-shaped entrance end face of an image guide type optical fiber is disposed so as to be displaceable on the spectral image plane of the transmitted light or reflected light of the sample. Since it can be narrower than the width of the detector, it is possible to select two wavelengths closer to each other than when the light-receiving surface of the solid-state image detector is placed directly on the spectral image plane, making it easier to select the sample for analysis. Gender etc. become wider.

Further, it is also possible to eliminate inconveniences such as the risk of wire breakage due to the configuration in which the solid-state image detector itself is movable.

It is well known that a sample spot generally has density unevenness, so that a measurement error will occur if the sample concentration is calculated by integrating the entire slit image and then converting the absorbance. However, in the present invention, even if there is density unevenness in the sample spot, a part of the sample spot is passed through the entrance slit to form a spectral image, and the relative intensity distribution of the spectral image is directly passed through the slit to a small detection element using an image-guided optical fiber. The spectral image of the sample spot is subdivided to the extent that the measurement error is negligible, and each detector Accurate measurements can be made by integrating the output after absorbance conversion.

Further, in the above embodiment, dual-wavelength photometry has been explained, but the invention is not limited to this; a large number of detectors and image-guided optical fibers are provided, and a combination of an appropriate detector and image-guided optical fiber is selected. By using the combination, a wide range of photometry methods can be selected.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a densitometer with a movable solid-state image detector, and FIG. 2 is a schematic diagram of an embodiment of the present invention. 2...Condensing lens, 3...Sample spot, 4...
... TLC plate, 5 ... Imaging lens, 6 ... Entrance slit, 6' ... Slit image, 7 ... Diffraction grating, 8 ... Spectral image plane, 9λ ₁ , 9λ ₂ ... Solid-state image detector, 10λ _{1,10λ 2} ...image guide type optical fiber.

Claims (1)

[Claims] 1. An entrance slit in which an image of the sample is formed based on the irradiated light, a spectroscopic element that separates the light that has passed through the entrance slit, and at least one pair of the above-mentioned slits that respectively detect the separated lights in the length direction. a densitometer comprising an array of solid-state image detectors, at least a pair of image-guided optical fibers each having an entrance end face and an exit end face each having a shape corresponding to the spectral image of the entrance slit; The above-mentioned solid-state image detectors are arranged so as to be freely displaceable in the wavelength dispersion direction on the spectral image plane of the spectroscopic element, and each of the above-mentioned solid-state image detectors is fixedly arranged, and the output end face of each of the above-mentioned image guide type optical fibers is arranged on the light-receiving surface of the solid-state image detector. A densitometer characterized by being arranged facing each other.