JPH08297088A - Spectrophotometer - Google Patents

Abstract

PURPOSE: To provide a spectrophotometer by which ultraviolet rays to visible rays can be measured not only in an instantaneous measurement but also in a high-S/N-ratio measurement in the spectrophotometer using a photodiode array. CONSTITUTION: In the spectrophotometer, two light sources 1, 2 are used, and measuring light which has been transmitted or reflected by a sample 7 is measured spectroscopically. In the spectrophotometer, a photodiode array detector 9 is used as a detector for spectroscopic measurement, and a changeover disk 10 which can change over a mirror, a semitransparent mirror and an opening part so as to be interposed selectively is provided on an optical path between the light sources 1, 2 and the sample 7 to be measured. Then, light from any one light source and composite light from both light sources are made incident on the sample 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spectrophotometer using a photodiode array as a detector.

[0002]

2. Description of the Related Art In a spectrophotometer for measuring the ultraviolet visible range,
Since there is no suitable light source that covers a wide wavelength range with one light source, two different light sources, specifically, a deuterium lamp for the ultraviolet region and a tungsten lamp for the visible region, are used depending on the measurement wavelength range. It is generally used properly.

On the other hand, some ultraviolet-visible spectrophotometers use a photodiode array as a detector. In the photodiode array detector, for example, 512 light receiving elements are arranged, and instantaneous measurement is performed by the light receiving element measuring the wavelength for each wavelength from the ultraviolet region to the visible region. In the measurement, two light sources are used one at a time or two at a time. FIG. 3 shows a conventional spectrophotometer with two light sources. In the spectrophotometer shown in FIG. 3, 1 is a light source A that is a deuterium lamp, 2 is a light source B that is a tungsten lamp, 3 is a rotatable switching mirror, 5 is a shutter that blocks the optical path, 6 is a condenser mirror, Reference numeral 7 is a sample, 8 is a grating, and 9 is a photodiode detector. The measurement with this device uses the following three modes properly. That is, in order to measure only the ultraviolet light region, a mode in which the switching mirror 3 is fixed at an angle for sending the light of the light source A1 to the sample 7 (hereinafter referred to as A single mode), and in order to measure only the visible light region Light source B
A mode in which the switching mirror 3 is fixed at an angle to send the light 2 to the sample (hereinafter referred to as B single mode), and the switching mirror 3 is used to measure from the ultraviolet light region to the visible light region.
Is used by switching the angle at which the light from the light source A1 is sent to the sample and the angle at which the light from the light source B2 is sent to the sample (hereinafter referred to as AB
It can be used in any one of the three modes. On the other hand, in the spectrophotometer shown in FIG. 4, the switching mirror 3 can take a position on the optical path and a position deviated from the optical path by drive control means (not shown). Then, when the switching mirror 3 is in the position on the optical path, the light of the light source B2 is sent to the sample, and when the switching mirror 3 is out of the optical path, the light of the light source A1 is sent to the sample. In the same manner as described above, it can be used in any of the three modes of A single mode, B single mode, and AB switching mode.

Further, in the other spectrophotometer shown in FIG. 5, not the switching mirror but the half mirror 4 is fixed on the optical path. This device can simultaneously send light from two light sources to the sample by turning on the light sources A1 and B2 at the same time. Therefore, in addition to the A single mode and the B single mode when the respective lamps are individually lit,
A mode in which two lights are superposed (AB combined mode) can be used.

[0005]

In a spectrophotometer using a photodiode array as a detector, an instantaneous measurement (about 0.1 second) is required in order to take advantage of the characteristic of the detector capable of simultaneously measuring multiple wavelengths. Ideally, it is performed over the entire range of measurement wavelengths. However, in the case where the measurement is performed in the AB switching mode when the measurement is performed over all wavelengths in the ultraviolet-visible region like the spectrophotometer of FIGS. 3 and 4,
Since it is necessary to switch the light source, instantaneous measurement cannot be performed and the measurement time becomes longer. On the other hand, in the spectrophotometer capable of using the AB combined mode like the device of FIG. 5, since light source switching is not performed, instantaneous measurement can be performed. However, the amount of light from both the A and B light sources is attenuated by the half mirror (for example, if the split ratio of the half mirror is 4: 6, the light from the A light source is 6).
0%, and the light from the B light source has lost 40% of the amount of light). Further, in the case of FIG. 5, since it is attenuated by the half mirror even when used in the A-only mode and the B-only mode, the SN ratio becomes worse than that in FIGS. 3 and 4.

A spectrophotometer using a photodiode array detector is most convenient for instantaneous measurement in the AB combined mode without loss of light quantity of the two light sources A and B. Realization is difficult. Therefore, as a method to follow this, if it is possible to select a suitable mode from four modes of A single, B single, AB switching, and AB composite with one spectrophotometer, it is suitable for the application. It becomes possible to measure. That is, if it is possible to select the most suitable mode depending on what is prioritized, such as when instantaneous measurement is prioritized or when measurement is performed by increasing the SN ratio, it is possible to perform more suitable measurement. .

An object of the present invention is to solve the above problems and to provide a spectrophotometer having two light sources, in which an appropriate mode can be selected according to the measurement wavelength region. To do.

[0008]

The spectrophotometer of the present invention made to solve the above problems has two different wavelength ranges.
The optical system uses two light sources and makes light from one or both of these light sources incident on the sample to be measured at the same time, a spectroscope that guides transmitted light or reflected light from the sample to be measured, and a spectroscope In a spectrophotometer including a photodiode array detector for performing spectroscopic measurement of light, any one of a mirror, a half mirror, and an opening is selectively interposed on the optical path between the light source and the sample to be measured. It is characterized in that a switching disk for switching in such a manner is provided, and light from one of the light sources and combined light from both of the light sources are made incident on the sample. Hereinafter, how this spectrophotometer works will be described.

[0009]

In the spectrophotometer of the present invention, when either one of the light sources is used alone, that is, in the A-only mode or the B-only mode, the disc opening or the mirror portion is positioned in the optical path. Thus, the light from either one of the light sources is incident on the sample without being attenuated.

On the other hand, when using the AB composite mode,
It is realized by placing the half mirror part of the disk in the optical path.

When the measurement is carried out from the ultraviolet region to the visible light region without instantaneous measurement, the AB switching mode is used, that is, the disc opening and the mirror are switched. In this way, according to the measurement conditions, there is no attenuation A alone, no attenuation B alone, there is attenuation but real-time UV-visible region measurement is possible AB composite, real-time measurement is not possible, but UV-visible region measurement is possible. It is possible to easily select and measure the optimum mode from among the AB switching modes that can be performed without attenuation.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a spectrophotometer showing an embodiment of the present invention. In the figure, the same parts as those in the conventional example shown in FIGS. 3, 4 and 5 are designated by the same reference numerals and the description thereof will be omitted. In the apparatus of the present invention, the light source A which is a deuterium lamp is used.
1 and a light source B2 which is a tungsten lamp, and a sample 7
A switching disk 10 is provided on the optical path between the and. As shown in FIG. 2, a mirror 15 and a half mirror 16 are attached to the surface of the switching disk 10, and an opening 17 is opened. A motor 11 for rotating the switching disk 10 is controlled by a control device (not shown). One of them can selectively intervene on the optical path by controlling the drive in accordance with the signal. That is, the two light sources A
1. When the mirror 15 comes to a position where the optical paths from the light source B2 intersect, the light from the light source B2 is reflected by the mirror and directed to the sample. In this case, the light from the light source A1 is blocked by the back surface of the switching disk 10 and does not reach the sample. When the opening 17 comes to a position where the optical paths from the two light sources intersect, the light from the light source A1 passes through the opening 17 and advances toward the sample. In this case, the light source B2
The light from the light does not reach the sample because it travels out of the optical path. Also,
Half mirror 1 at the position where the optical paths from two light sources intersect
When 6 comes, the light from the light source A1 and the light from the light source B2 are both attenuated by a certain amount and then travel toward the sample.

Further, as shown in FIG. 2, the switching disk 1
A shutter 18 and a filter 19 can also be provided at 0. Among them, the shutter 18 bends a part of the plane of the switching disk 10 slightly toward the sample side so that the light from both the light sources 1 and 2 can be blocked, so that the light from the light source 1 is surely blocked. There is. Various filters are attached to the filter 19 depending on the purpose. For example, a holmium filter is used as a filter for checking the wavelength accuracy of a spectrophotometer, and a sharp cut filter or bandpass filter is used as a filter for emitting only light in a specific wavelength range. However, a filter suitable for each purpose of use is mounted on the disc. The filter used for the light from the light source B2 in FIG. 1 can be used as a filter for the light source B2 by providing a mirror on the back side of the filter.

In this embodiment, the optical paths of the two light sources intersect each other at a right angle, and the optical elements on the disk 10 are arranged at the intersections of the optical paths so that they form an angle of 45 degrees with respect to the respective optical paths. However, it is not limited to this. For example, a switching disk is formed so that the included angle between the optical paths of the two light sources is different from the right angle (for example, 60 degrees), and the included angle is equally divided into two (if the included angle is 60 degrees, the included angle is 30 degrees). May be attached. By doing so, the split ratio of the half mirror can be set appropriately. In short, the angle formed by the optical paths of the light sources can be appropriately selected by setting the relationship in which the disks are arranged so as to divide the included angle into two equal parts with respect to the included angle between the optical paths from the two light sources.

Next, the operation of the present invention will be described. When it is desired to use only the A single mode, that is, only the light source A1, the switching disk 10 is rotated to move the opening 17 onto the optical path.
Then, only the light from the light source 1 can travel toward the sample. At this time, the light from the light source B2 does not reach the sample because it travels out of the optical path. On the other hand, B single mode, that is, light source B
If only two is desired, the switching disk 10 is rotated to move the mirror 15 on the optical path. Then, the light from the light source B2 is reflected by the mirror and goes to the sample. At this time, the light from the light source A1 is blocked by the back surface of the disk 10. If the stability of the light source does not matter, the light source B2 may be turned off in the A single mode, and the light source A1 may be turned off in the B single mode.

When the AB composite mode is used, the switching disk 10 is rotated to move the half mirror 16 on the optical path. Since both the light from the light source A1 and the light from the light source B2 travel toward the sample through the half mirror, light over a wide wavelength range can be applied to the sample at the same time, and transmitted light or reflected light from the sample can be detected by the photo. The spectrum for each wavelength can be measured instantaneously by the diode array detector. In this case, it is possible to instantaneously measure a wide range of spectrum from ultraviolet to visible, but part of the light from the light source is attenuated by the beam splitter, which deteriorates the SN ratio of the measurement.

Therefore, if it is inferior in terms of instantaneous measurement but it is desired to increase the SN ratio for measurement, the AB switching mode is used.
In this case, the switching disk 10 is controlled by a controller (not shown) so that the position of the mirror 15 and the position of the opening 17 are alternately switched. When the mirror 15 reaches the optical path, the data from the element of the photodiode array detector 9 that measures the wavelength region of the light source B2 is taken in. Further, when the opening 17 reaches the optical path, the data from the element of the photodiode array detector 9 for measuring the wavelength region of the light source A1 is taken in. Therefore, although the measurement using the two light sources is performed alternately, the light from the light sources 1 and 2 is incident on the sample without being attenuated, so that the measurement with a better SN ratio can be performed.

Further, by rotating the switching disk 10 to move the filter 19 on the optical path, the filter 19
It is possible to transmit only the light of the predetermined wavelength selected by the above and send it to the sample.

Further, by rotating the switching disk 10 to move the shutter 18 onto the optical path, it is possible to block the light without providing a shutter driving mechanism which is conventionally provided separately, thus simplifying the overall structure. be able to. This enables dark current measurement and background correction. The following is a summary of some embodiments of the present invention. (1) An optical system in which two light sources having different wavelength ranges are used, and light from only one of these light sources or both of them are simultaneously incident on the sample to be measured, and a spectroscope in which transmitted light or reflected light from the sample to be measured is guided In a spectrophotometer including a detector and a photodiode array detector that performs spectroscopic measurement of light dispersed by the spectroscope, on the optical path between the light source and the sample to be measured, a mirror, a half mirror, an opening, A spectrophotometer having a switching disk for selectively switching one of the filters so that light from one of the light sources and combined light from both light sources are incident on the sample. . (2) An optical system in which two light sources having different wavelength ranges are used, and light from only one of these light sources or both of them are simultaneously incident on the sample to be measured, and a spectroscope in which transmitted light or reflected light from the sample to be measured is guided In a spectrophotometer including a detector and a photodiode array detector that performs spectroscopic measurement of light dispersed by the spectroscope, on the optical path between the light source and the sample to be measured, a mirror, a half mirror, an opening, A spectrophotometer comprising a switching disk for selectively switching one of the shutters so that light from one of the light sources and combined light from both light sources are incident on the sample. .

[0020]

As described above, according to the present invention,
Since at least the mirror, the half mirror, and the switching disk capable of switching the opening are provided on the optical path, in the spectrophotometer having two light sources, the A light source and the B light source,
Any of A single mode, B single mode, AB switching mode, and AB complex mode can be freely selected, and the AB complex mode can be used in the measurement of a wide wavelength range from ultraviolet to visible by the photodiode array detector. Thus, it is possible to freely select to perform an instantaneous measurement or to perform an excellent measurement of the SN ratio in the AB switching mode. Moreover, since the A and B single modes can be measured without passing through the beam splitter, the single mode can be measured with high sensitivity without being attenuated.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a spectrophotometer that is an embodiment of the present invention.

2A and 2B are configuration diagrams of a switching disc of a spectrophotometer according to an embodiment of the present invention, in which FIG. 2A is a front view thereof and FIG. 2B is a side view thereof.

FIG. 3 is a block diagram of a conventional spectrophotometer.

FIG. 4 is a block diagram of a conventional spectrophotometer.

FIG. 5 is a block diagram of a conventional spectrophotometer.

[Explanation of symbols]

 1: Light source A (deuterium lamp) 2: Light source B (tungsten lamp) 6: Condensing mirror 7: Sample 8: Grating 9: Photodiode detector 10: Switching disk 11: Motor 15: Mirror 16: Half mirror 17: Opening 18: Shutter 19: Filter

Claims (1)

[Claims] 1. An optical system which uses two light sources having different wavelength ranges and makes light from one or both of these light sources incident on a sample to be measured and a transmitted light or a reflected light from the sample to be measured are guided. In a spectrophotometer equipped with a spectroscope and a photodiode array detector that performs spectroscopic measurement of light dispersed by the spectroscope, a mirror, a half mirror, an aperture is provided on an optical path between a light source and a sample to be measured. A spectrophotometer, characterized in that it is provided with a switching disk for selectively switching one of the parts so that light from one of the light sources and combined light from both light sources are incident on the sample. .