JPS62222132A - Wavelength detecting method - Google Patents

Abstract

PURPOSE:To make it possible to detect the wavelength of monochromatic light simply with good accuracy, by respectively alternately placing a first filter and a second filter on the light path between a spectroscopic machine and a light receiver for a spectrophotometry. CONSTITUTION:At first, a first filter 11 is placed on the light path between a spectroscopic machine and a light receiver 10 for spectrophotometry and output value (a) from the light receiver 10 for spectral photometry at this time is measured. Next, the first filter 11 is removed from the light path to place a second filter 12, which has spectral transmittance different in the ratio from that of the first filter 11 for each wavelength within a range desired to detect a wavelength, on the light path and the output value (b) from the light receiver 10 for spectrophotometry is measured. Next, the ratio a/b of measured values is calculated. On the basis of functional relation at this time, a wavelength can be detected from the ratio a/b. By this method, by reading the output value from the light receiver for spectrophotometry while wavelength feed is performed by the spectroscopic machine 9, the wavelength of monochromatic light can be detecting simply with good accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides a method for detecting wavelengths of monochromatic light in spectroscopic instruments.

Conventional techniquesIn order to predict the color of an object illuminated by a lighting source,
It is necessary to accurately measure the spectral distribution of a light source and the spectral reflectance of an object. For this purpose, spectroscopic instruments such as a prism monochromator or a diffraction grating monochromator are used.

In measurements using these spectroscopic instruments, it was important to accurately detect the wavelength of the monochromatic light being measured. Taking a diffraction grating monochromator as an example, the wavelength being measured corresponds to the angle of inclination between the optical axis of the incident light to be measured and the surface of the diffraction grating, so the wavelength can be determined from the angle of inclination. It is being calculated. At this time, due to (1) errors due to mechanical wear of the mechanism that calculates the wavelength from the tilt angle, (2) the diffraction grating was replaced to change the measurement range, the tilt angle of the diffraction grating and the wavelength Because the relationship between the diffraction grating and the diffraction grating may change, it was necessary to frequently calibrate the wavelength and tilt angle of the diffraction grating by inputting monochromatic light. Normally, for this calibration, one of the emission lines of a light source with known emission characteristics, such as a high-pressure mercury lamp, whose wavelength has changed, is incident on a diffraction grating monochromator, and a light receiver is placed at the exit port.
The wavelength calculated from the inclination of the diffraction grating when the receiver output is maximum is read, and the mechanism that calculates the wavelength from the inclination angle of the diffraction grating is adjusted until this value matches the wavelength of the emission line. It was very time-consuming.

To avoid this, the wavelength of light output from a spectroscopic device has conventionally been detected using a wavelength detection device with a block configuration as shown in Figure 2. In FIG. 2, 1 is a first light receiver;
2 is a second light receiver, 3 is a first calculation section, 4 is a second calculation section, and 5 is a display section.

The operation of the conventional wavelength detection device will be described below with reference to FIG.

A first light receiver 1 and a second light receiver 2 receive monochromatic light to be measured. The first calculation unit 3 inputs the signal from the first light receiver 1 and the signal from the second light receiver 2,
Output a signal corresponding to those ratios. In Figure 3, the first
An example of the spectral sensitivity of the photoreceiver 1 (curve A) and the spectral sensitivity of the second photoreceiver (curve B) of FIG. Of these, the first
Although the shape of the spectral sensitivity curve A of the light receiving section is arbitrary, the shape of the second
The shape of the spectral sensitivity curve B of the receiver has a spectral sensitivity value that does not have the same proportional relationship to the spectral sensitivity value of the first receiver in the wavelength range of the monochromatic light to be measured. shall be taken as a thing. The second calculation unit 4 determines the measurement target based on the ratio of the signal from the first photoreceiver 1 and the signal from the second photoreceiver 2, which has been determined in advance, and the functional relationship between the wavelength of the monochromatic light. Calculate the wavelength of monochromatic light. FIG. 4 shows an example of the relationship input to the second calculation unit 4. Display section 5
Now, the contents of the second calculation section 4 will be displayed.

An example of how to use a conventional wavelength detection device is shown in FIG. In FIG. 5, 6 is a spectroscopic device, 7 is a wavelength detection device according to the present invention, and 8 is a spectrophotometric photoreceiver. When performing normal spectrophotometry, light from the spectroscopic device 6 is received by the spectrophotometer photoreceiver 8, and its output value is used as the measured value. When calibrating the wavelength of the spectroscopic device 6, the spectrophotometric receiver 8
The wavelength detection device 7 according to the present invention is placed in the position where the spectroscopic device 6 was placed, and the mechanical parts of the spectroscopic device 6 are adjusted so that the value shown on the display section 5 matches the value shown on the wavelength scale of the spectroscopic device 60. .

However, in the usage method shown in Figure 5, good accuracy cannot be obtained unless the wavelength detection device and the spectrophotometric receiver are set alternately on the optical axis of the spectroscopic instrument, and this setting is time-consuming. This was the case.

Problems to be Solved by the Invention As mentioned above, in the conventional example, it took time and effort to alternately set the wavelength detection device and the spectrophotometric receiver on the optical axis of the spectroscopic device with high accuracy. .

A means to solve the problem is to use a first filter having an arbitrary spectral transmittance and a spectral transmittance such that the ratio of the spectral transmittance of the filter is different for each wavelength within the range in which the wavelength is to be detected. and second filters are placed alternately in the optical path between the spectroscopic instrument and the spectrophotometric receiver.

Calculating the ratio of the output from the spectrophotometric photoreceptor when the first filter is placed in the optical path and the output from the spectrophotometric photoreceptor when the second filter is placed in the optical path, The wavelength of light output from the spectroscopic device is calculated based on the value of this ratio.

Embodiment An embodiment based on the wavelength detection method according to the present invention will be described with reference to FIG. In FIG. 1, 9 is a spectroscopic device, 10 is a spectrophotometric receiver, 11 is a first filter, and 12 is a second filter.
This is a filter.

In FIG. 1, first, the first filter 11 is placed on the optical path between the spectroscopic device 9 and the spectrophotometric photoreceptor 1o, and the output value a from the spectrophotometric photoreceptor 1o at this time is measured.

After removing the first filter 11 from the optical path, the second filter 12 is placed in the optical path, and the output value from the spectrophotometric photoreceptor 1o at this time is measured. Note that examples of the spectral transmittance curves of the first filter f and the spectral transmittance curves of the second filter 12 include curves A and B shown in FIG. 3, respectively. Of course, the signal from the spectrophotometric receiver 1o when the first filter 11 is placed in the optical path of the spectroscopic device and the signal from the spectrophotometric receiver 10 when the second filter 12 is placed in the optical path. As a result,
Functions that do not have the same value in the wavelength range to be measured (
For example, the same effect can be obtained by determining the spectral transmittance of the first filter 11 and the spectral transmittance of the second filter based on a monotonically increasing or decreasing function, and calculating the wavelength based on this functional relationship. Needless to say, you can obtain

After the measurement, the ratio a/b of the measured values is calculated.

Regardless of the spectral sensitivity of the spectrophotometric photoreceiver 1o, this value is determined by the first calculation unit 3 in the conventional wavelength detection device.
It is similar to the output value from .

Based on the functional relationship shown in Figure 4, the ratio of measured values a/b
The wavelength can be detected from

ND in the optical path between the spectroscopic device 9 and the spectrophotometric receiver 10
Ordinary spectrophotometry can be performed by not placing anything other than a filter and reading the output value from the spectrophotometer photoreceiver 1Q while transmitting the wavelength using the spectrometer 9. For this reason, there is no need to align the spectrophotometric receiver with the optical axis of the spectroscopic instrument, as would be the case after using a conventional wavelength detection device.

Furthermore, although the present invention has been described as a wavelength detection method used for calibrating a spectroscopic device, it can also be used as a method for detecting the wavelength of monochromatic light generally output from a spectroscopic device. By using this method as a display device for the wavelength of monochromatic light output from a spectroscopic device, for example, in a diffraction grating monochromator, it is possible to avoid spectrophotometric measurements due to errors (backlash) caused by play in the mechanism that rotates the diffraction grating. This solves the problem that the wavelength output from a spectroscopic device could only be adjusted in either an ascending or descending direction.
Spectrophotometry can be performed quickly.

Effects of the Invention According to the present invention, the wavelength of monochromatic light can be detected without the need to remove the spectrophotometric light receiver from the optical path of the spectroscopic device.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the wavelength detection method according to the present invention, FIG. 2 is a block diagram of a conventional wavelength detection device, and FIG. Figure 4 is a diagram showing an example of the spectral sensitivity of the optical receiver of No. 2, Figure 4 is a diagram showing an example of the function that is input in advance to the second calculation section of a conventional wavelength detection device, and Figure 5 is a diagram showing an example of the spectral sensitivity of the conventional wavelength detection device. It is a figure showing an example of the example of use of a detection device. 9... Spectroscopic equipment, 10... - Spectrophotometric receiver, 11... First filter, 12...
...Second filter. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 3 Figure 41 Grudge shooting - Bunjo Figure 5

Claims (1)

[Claims] A first filter having an arbitrary spectral transmittance and a second filter having a spectral transmittance such that the ratio of the spectral transmittance of the filter to the spectral transmittance of the filter differs for each wavelength within the range in which the wavelength is to be detected. Alternately placed in the optical path between the spectroscopic instrument and the spectrophotometric receiver, the output from the spectrophotometric receiver when the first filter is placed in the optical path and the output from the spectrophotometric receiver when the second filter is placed in the optical path. 1. A wavelength detection method comprising: calculating a ratio between the output from a spectrophotometric photoreceptor and calculating the wavelength of light output from a spectroscopic device based on the value of this ratio.