JPS626493Y2 - - Google Patents

Description

[Detailed explanation of the invention] This invention irradiates a sample object and a standard object with a beam of light,
The reflected light or transmitted light from each object is guided to a dispersive element, this dispersed light is detected simultaneously by multiple detectors, and this detection signal is processed to measure the color characteristics of the sample object. This invention relates to a spectrophotometric device.

Conventionally, when measuring color by shining light onto an object,
Light sources such as xenon lamps are used to ensure the light intensity on the short wavelength side of the luminous flux that irradiates objects, but the light intensity of these lamps fluctuates in the high frequency region and in the very low frequency region. It cannot be said to be constant over time. The luminous flux of these light source lamps is irradiated onto the standard object and the sample object, and the two luminous fluxes, the reflected light from the standard object and the reflected light from the sample object, are temporally divided and placed on one optical path using a chipper mirror, etc. In this case, if the standard signal and sample signal are guided alternately and incident on the spectrometer, there is a time difference between the standard signal and the sample signal.
Insufficient reproducibility. In addition, if the light flux is not time-divided and enters the spectrometer as two light fluxes, the spectrometer, detector, and signal processing unit will be twice as necessary compared to when one light flux is used, making the configuration of the device complex and expensive. It becomes a thing. In particular, this method is completely unsuitable for practical use when attempting to shorten measurement time by arranging a large number of detectors and simultaneously measuring multiple wavelengths.

The present invention aims to provide a spectrophotometric device using a time-division method with a simple configuration and excellent colorimetric accuracy and reproducibility. a luminous flux switching mechanism that causes the luminous flux from the dispersion element to enter the dispersion element alternately;
A plurality of analog integrators that integrate the detection signal for each of the above detectors and reset when switching the luminous flux, an analog-to-digital converter that converts the integration results of the analog integrators into digital signals, and a signal from the converter. The apparatus is equipped with an adding device that separates and adds signals from a sample object and a signal from a standard object, and the results of this adding device are used to perform colorimetric calculations.

The present invention will be explained below based on examples. 1st
The figure is a schematic diagram for explaining the operation of the present invention.
1 is a light source, 2 is an integrating sphere, 3 is a standard object, 4 is a sample object, 5 is a switching mirror, 6 is a reflecting mirror, 7 is a slit,
8 is a dispersion element, 9 is a detector, 10 is an analog integrator, 11 is an analog-digital converter (A-D converter), 12 is a standard signal addition section, 13 is a sample signal addition section, 14 is dark (blank) Signal addition section, 15
1 is an output display, and 16 is a control device (for example, a microcomputer). FIG. 2 is a diagram for explaining the relationship between the output signal intensity of the detector 9 and time, and the signal B in period B is the output signal of the detector 9 ( The signal S in the period S is the output signal of the detector 9 during the period in which the reflected light flux from the sample object 4 is incident on the dispersion element 8 (hereinafter referred to as the sample signal S), and the signal R in the period R is the dispersion element 8
The output signal of the detector 9 during the period in which the reflected light flux from the standard object 3 is incident (hereinafter referred to as the standard signal R), and the signal T in the period T is the signal during the transition between the signals B, S', and R (hereinafter referred to as the transition signal). (denoted as signal T). The operation of the above configuration will be explained next.

Light from light source 1 is first introduced into integrating sphere 2,
The luminous flux averaged by the integrating sphere 2 is the standard object 3
and the sample object 4 is irradiated. The reflected light from the standard object 3 and the reflected light from the sample object 4 are each taken out from the integrating sphere 2, guided onto a single optical path in a time-sharing manner by the switching mirror 5 and the reflecting mirror 6, and then passed through the slit. The light flux is incident on a dispersive element (for example, a crating) 8 through the dispersive element 7, and is dispersed by this dispersive element, and detected by a detector 9 for each dispersed wavelength. The same thing is provided, but for convenience of explanation, we will explain it as one.) The output signal of this detector 9 is as shown in FIG. Since the transition signal T is an unnecessary signal during transition, it is cut and is not introduced into the analog integrator 10. The following dark signal B is, so to speak, a baseline signal of the detection system, and this dark signal B is introduced into the analog integrator 10 (the analog integrator 10 is reset immediately before the transition signal T switches to the signal B). At the end of the dark signal B, this integration result is sent to the A-D converter 1.
1 and is converted into a digital signal and stored in the dark (blank) signal adder 14 as a digital signal. The next transition signal T is cut off, and once the analog integrator 10 has been reset, the dark signal B
As in the case of , the sample signal S is analog-integrated and digitized and stored in the sample signal addition section 13 . The next transition signal T is cut off, the analog integrator 10 is reset again, and the transmitted light from the standard object 3 is integrated with the standard signal R of the detector 9 by the analog integrator 10, and the integration result is immediately converted into a digital signal. and stored in the standard signal adder 12. Then, this measurement and signal processing process is repeated many times to obtain dark signal B and standard signal R.
and sample signal S are separated and accumulated. That is, the dark signal B, standard signal R, and sample signal S are digitally integrated separately.

As is clear from the above explanation, high-frequency fluctuations in the light source (thin fluctuations in each signal waveform in the figure) can be averaged and removed by performing analog integration at short intervals in the analog integrator 10. In addition, slow fluctuations in the light source at low frequencies can be averaged and removed by converting the signal results of analog integration into digital signals and adding them together over a long period of time (digital integration). . Since it is digital integration, there is no worry about drift during the accumulation stage. Furthermore, after this, (integrated value of the sample signal addition section 13) - (integrated value of the dark signal addition section 14)/(integrated value of the standard signal addition section 12) - (integrated value of the dark signal addition section 14), the control device 16 After determining the reflectance, colorimetric calculation is performed and displayed on the output display 15. In this example, t ₁ = 22×10 ^-3 (seconds), t ₂ = 10×10 ^-3
(seconds), if repeated measurements are taken 30 times, and one measurement is completed in 2 seconds, the reproducibility of this data will be within ±0.020% at 100% reflectance.
It was confirmed that this was significantly improved compared to the conventional method.

In this embodiment, the measurement of the dark signal B can be omitted when there is very little drift in the electrical system after the detector.

FIG. 3 shows more specifically the front and rear configuration of the detector 9 of the embodiment of the present invention, and the same numbers as in FIG. 1 are the same as those in FIG. 1. be. In FIG. 3, 18 is a preamplifier and 17 is a multiplexer. To explain the main point, the light beam from the standard object 3 and the light beam from the sample object 4 passing through the slit 7 are introduced into the dispersion element 8, and the light beams are dispersed for each wavelength and detected by the detector 9 corresponding to the wavelength. be done. After the signal from each detector 9 is amplified by a preamplifier 18,
Analog integration is performed by an analog integrator 10. The outputs of each analog integrator 10 are sequentially guided by a multiplexer 17 to an A/D converter 11, converted into digital signals, and then divided into wavelengths and integrated.

FIG. 4 is a diagram for explaining the main parts of the device of the present invention which measures transmitted light from an object. The transmitted light beams from the standard object 3 and the sample object 4 are emitted from the slit 7 in a time-division manner by the mirror 6 and the switching mirror 5. Since the process after being emitted from the slit 7 is the same as that shown in FIG. 3, the explanation will be omitted.

In FIG. 1, the light source 1 is provided outside the integrating sphere, but it goes without saying that it may be provided inside the integrating sphere.

As detailed above, the present invention eliminates the effects of fluctuations in the high frequency region and low frequency region of the light source by using an extremely simple configuration of a combination of an analog integrator and a digital integrator. It is possible to improve the reproducibility and accuracy of color measurement results, and it can be said that the effect is extremely large in practical use.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram for explaining the operation of the present invention, FIG. 2 is a diagram showing the relationship between the output signal of the detector 9 and time, and FIG. 3 is a diagram specifically showing the configuration before and after the detector 9. FIG. 4 is an explanatory diagram of the main parts of a spectrophotometric device using transmitted light flux. 1... Light source, 2... Integrating sphere, 3... Standard object,
4... Sample object, 5... Switching mirror, 6... Reflecting mirror,
7... Slit, 8... Dispersion element, 9... Detector, 10... Analog integrator, 11... Analog-digital converter, 12... Standard signal adder, 1
3...Sample signal addition section, 14...Dark signal addition section,
15... Output indicator, 16... Control device, B...
A period in which no light beam is incident on the dispersive element, S... A period in which a light beam from the sample object is incident on the dispersive element, R
...The period during which the light flux from the standard object is incident on the dispersive element.

Claims (1)

[Claims for Utility Model Registration] (1) Irradiating a sample object and a standard object with a light beam, guiding the reflected light or transmitted light from each object to a dispersion element, and detecting the dispersed light in multiple pieces. A light flux switching mechanism that alternately causes a light flux from the sample object and a light flux from the standard object to enter the dispersion element; A plurality of analog integrators that integrate the detection signal for each detector and reset when switching the light flux, an analog-to-digital converter that converts the integration results of the analog integrators into digital signals, and a signal from the converter. A spectrophotometric device comprising an addition device that separates and adds signals from a sample object and a signal from a standard object, and performs colorimetric calculations using the results of the addition device. . (2) The luminous flux switching mechanism is a luminous flux switching mechanism that produces a blank period in which both luminous fluxes are cut off, and the analog integrator is an analog integrator that performs a reset operation when switching between the blank period and another luminous flux period. , wherein the adding device is an adding device that separates and adds the detection signal of the blank period from the signal from the sample object and the signal from the standard object. Color device.