JPS5961753A - Densitometer - Google Patents

Abstract

PURPOSE:To widen the selectivity of two wavelengths and the selectivity of a specimen, by a method wherein the incident end surfaces of a pair of optical fibers are arranged to the surface of a spectrum image toward a wavelength dispersing direction in a freely displaceable manner and the emitting end surfaces thereof are arranged in opposed relation to a solid image detector. CONSTITUTION:The light issued from a white light source 1 is passed through a condensing lens 2, a specimen spot 3 on a plate and an image forming lens 5 and formed into an image 3' on the slit 6 of a spectroscope while the pervious light is subjected to spectral diffraction image formation by a concave diffraction grating 7. The light from said grating 7 is incident to the incident end surfaces Ilambda1, Ilambda2 of image guide type optical fibers 10lambda1, 10lambda2 parallelly arranged on an image surface 8 in a displaceable manner and guided to light detectors 9lambda1, 9lambda2 through the emitting end surfaces Elambda1, Elambda2 thereof to perform concn. measurement due to two-wavelength measuring light. Because the optical fiber is used, the selectivity of two wavelengths and the selectivity of a specimen are widened in range.

Description

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

As solid-state image detectors, for example, photodiode sub-door arrays have been developed, but these have small light-receiving elements, the ability to arrange these light-receiving elements in a straight line or a planar shape, and fast response. It has the following characteristics and is used as a densitometer detector in combination with a spectrometer.

FIG. 1 is a schematic diagram of the concentration g1 configured to perform the well-known three-wavelength measurement using this solid-state image detector.
In the figure, l is a white light source, 2 is a condensing lens, and 3 is a sample spot developed on a sample to be measured, for example, a TLO plate 4. The condensing lens 2 condenses the light from the light source 1 onto the spot 3 and irradiates it. do.

In the figure, the light source 1 is arranged for transmission, but a reflection light source (not shown) may be provided alternatively or additionally for alternative use.

The transmitted light or the reflected light from the sample spot 3 is imaged by the imaging lens 5 onto the entrance slit 6 of the spectrometer as the ray ψ31 of the spot 3. The light from the measurement target portion of this spot Φ31 enters a spectrometer (for example, a concave diffraction grating) 7 from the entrance slit 6 and is spectrally separated.

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, an arbitrary image can be formed. Photometry at wavelength can be performed.

In this case, to perform two-wavelength photometry, for example, two detectors 9λ1 and 9λ2 are placed at desired wavelength positions on the spectral image plane 8, and to select two wavelengths, each detector is placed at the desired wavelength position on the spectral image plane 8. Wavelength dispersion direction (lateral direction) on image plane 8
(Note that this is also possible by a combination of the displacement of the detector and the 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 intermittent points 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 must be pulled each time the detector position is changed to select a wavelength. I decided to do it,
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 distance, and it is impossible to select a wavelength simply.

In order to overcome the above drawbacks, the present invention arranges the entrance end surfaces of at least a pair of optical fibers each having a slit-shaped entrance and exit end surface 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.

The present invention will be described in detail below with reference to FIG.
In FIG. 2, the same reference symbols as in FIG. 1 indicate the same corresponding elements as in FIG. 1, and the explanation thereof will be omitted.

According to the invention, the solid-state image detector 9λ1,9λ2 is not placed on the spectral image plane 8, but is fixedly placed at a suitable position fa in the device. 1oλ1.1oλ2 are image guide type optical fibers, each having a narrow slit-shaped entrance end face (image guide surface) with a diameter of λ1 and a diameter of λ.
2 and the output end surface EλISXλ2, the input end surface λ1 and the 0-incidence end surface EλISXλ2 almost match the height and width of the above-mentioned slit image 6', respectively, and the spectral image surface 8
At the top, they are arranged in parallel so that they can be displaced separately in the wavelength dispersion direction, while the output end surfaces Eλ1 and Eλ2 are respectively aligned with the detectors 9.
They are arranged opposite to the light receiving surface of λ1.9λ2.

Therefore, by arranging the incident end beams λ1 and λ2 at the positions of desired wavelengths λ and λ2 on the spectral image plane 8, respectively, light of the wavelengths can be guided to the detectors 9λ and 9λ2.

In this case, it is necessary to project the image on the spectral image plane 8 onto the light-receiving surface of the detector 9λ1.9λ2 without distorting it. It is necessary that each fiber (strand) constituting this optical fiber at the output end faces Eλt, Kλ2 and Eλt, Kλ2 be arranged so as to occupy corresponding geometrical same positions on both end faces.

The outputs of the detectors 9λ1, 9λ2 are then amplified and processed by a suitable circuit or device depending on the purpose of the measurement.

As described above, in the present invention, the slit-shaped 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 the width of the detector can be made narrower than the width of the detector, it is possible to select two wavelengths that are closer to each other than when the light-receiving surface of a solid-state image detector is placed directly on the spectral image plane. The selectivity, etc. of

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.

In addition, since there is generally uneven concentration in the sample spot,
It is well known that measurement errors occur when 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 formed into a spectral image through the entrance slit, and the relative intensity distribution of the spectral image is directly transferred to the slit using an image-guide optical fiber. Since the spectral image of the sample spot is subdivided to the extent that the measurement error can be ignored, each detector Accurate measurements can be made by integrating the output after absorbance conversion.

Further, in the above embodiment, dual wavelength photometry was explained, but the detector and image guide type optical fiber are not limited to this. 1. By using a combination of a suitable detector and an image guide type optical fiber, a wide range of photometry methods can be selected.

[Brief explanation of the drawing]

FIG. 1 is a schematic block diagram of the concentration Nl with a movable solid-state image detector, and FIG. 2 is a schematic block diagram of one embodiment of the present invention. 2... Condenser lens, 3... Sample spot, 4
-@TLO plate, 5...imaging lens, 6...entrance slit, 61
...Slit image, 7...Diffraction grating, 8...e spectral image plane, 9λ weight, 9λ2...Solid image detector, 10λ,
, 10λ2 ・ ・ ・Image guide type optical fiber.

Claims (1)

[Claims] an entrance slit in which an image of the sample is formed based on the irradiated light; and a spectroscopy system that separates the light that has passed through the entrance slit;
and at least one pair of solid-state image detectors arranged in the longitudinal direction of the slits for detecting the separated light, respectively, in which a correspondingly shaped incident light is formed on the spectral image plane of the entrance slit. At least a pair of image guide type optical fibers having an end face and an output end face are provided, and the entrance end face of each optical fiber is disposed so as to be freely displaceable in the wavelength dispersion direction on the spectral image plane of the spectroscopic element, and each of the solid-state images is detected. 1. A densitometer, characterized in that a light-receiving surface of the solid-state image detector and the output end surface of each of the image guide type optical fibers are arranged opposite to each other.