JPS5943321A - spectrophotometer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a spectrophotometer for measuring spectral transmittance, absorption spectrum, absorption intensity, etc. of a sample.

Spectrophotometers that use photodiode arrays as photodetectors traditionally use diffraction gratings as dispersion elements.

The reason why a diffraction grating was used is that the diode elements of a photodiode array are usually arranged at equal intervals, and the dispersed light is less affected by wavelength, so it can be used from the visible region to the ultraviolet region. It is based on the fact that the dispersion angle is approximately constant.

However, the diffraction grating has a large amount of stray light and secondary light, making it difficult to perform accurate measurements. In order to remove these stray lights and secondary lights, attempts have been made to use cut filters, bandpass filters, etc., but each element of the photodiode array is extremely small, and incorporating a filter for each wavelength is difficult due to processing and processing. When considering position adjustment, etc., it was extremely difficult.

An object of the present invention is to provide a spectrophotometer that eliminates these drawbacks and allows highly accurate measurements.

In order to achieve such an object, the present invention includes a prism that disperses monochromatic light that has passed through a sample, a diode array in which each diode element is arranged at equal intervals and receives light from the prism, and a diode array that receives light from the prism. The device consists of a diode array that receives light from the prism, and a circuit that processes the outputs of a plurality of diode elements that receive the same dispersed light from the prism as one signal.

Hereinafter, the present invention will be explained in detail using Examples.

FIG. 1 is a block diagram showing an embodiment of a spectrophotometer according to the present invention. In the figure, white light 7 emitted from a light source 1 enters a sample chamber 2. This results in
Light passing through the cell 3 containing the sample enters a spectrometer 4. Here, the light entering the spectroscope 4 is transmitted through the prism 5
The light is separated into monochromatic light 8 by the photodiode array 6, and is received by the photodiode array 6. As shown in FIGS. 2(a) and 2(b), the photodiode array 6 has photodiode elements 14 arranged in a package. The width of each photodiode element 14 is, for example, 77 μm, and the pitch thereof is 123 μm. The light receiving surface is protected by a window 13, and each photodiode element 14 has a pin 15 for signal extraction.
is connected to. As shown in FIG. 3, each photodiode element 14 of the photodiode array 6 configured in this manner extracts the outputs of the plurality of diode elements 14 that receive the same monochromatic light dispersed by the prism 5 as one signal. are connected to each other in such a way that

Each signal taken out from each photodiode element is input to a shift register and multiplexer 9, and the output of this shift register and multiplexer 9 is input to a data processor (CPU) 10. The output of the data processor (CPU) 10 is output to a CRT 11 and a recorder 12.
11 and recorder 12 to record data.

In this way, stray light and secondary light will not be generated due to the nature of the prism, and the arrangement of photodiode elements based on the difference in dispersion angle due to the use of the prism is shown in Figure 3. By connecting the outputs of a plurality of diode elements receiving the same monochromatic light as one signal, it becomes possible to use a photodiode array arranged at regular intervals, that is, a conventional photodiode array as is.

In addition, in the ultraviolet region where the energy of the light source and the sensitivity of the diode elements decrease, the light receiving area of the photodiode elements that are commonly connected to each other can be expanded, and the S/N
will be able to improve their performance.

As is clear from what has been described above, the spectrophotometer according to the present invention enables highly accurate measurements.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a spectrophotometer according to the present invention, FIG. 2 is a block diagram showing an embodiment of a photodiode array included in the spectrophotometer, and FIG. 3 is a block diagram showing an embodiment of a photodiode array provided in the spectrophotometer. FIG. 2 is a configuration diagram showing an example of how each diode element of the array is connected. 1...Light source, 2...Sample chamber, 3...Cell, 4...
- Spectrometer, 5... Prism, 6... Photodiode array, 9... Shift register and multiplexer, 10... Data processor (CPU), 11...
・CRT, 12...Recorder, 13...Window.

Claims (1)

[Claims] 1. A prism that disperses the light that has passed through the sample into monochromatic light;
Consisting of a diode array in which each diode element is arranged at equal intervals and receives light from the prism, and a circuit that processes the outputs of the plurality of diode elements that receive the same monochromatic light from the prism as one signal. A spectrophotometer featuring: