Shimadzu Corporation

Shimidzu Corporation of 1

Tatsumi Sato

Osamu Ando

Toshiaki Fukuma

Hidehisa Nishigaki

In a double beam spectrophotometer, a sample beam is irradiated to a large-sized sample in a substantially vertical direction, and the beam upwardly transmitted through the large-sized sample is reflected by a reflecting mirror and sent to an integrating sphere including a detector. A reference beam irradiated parallel to the sample beam is deflected by reflecting mirrors such that the reference beam goes around the large-sized sample, and guided to the integrating sphere. Thus, a holder is not required to correspond to a size or shape of the sample, and measurement position can be freely changed by moving the sample. Also, in case of utilizing a conventional standard sample chamber, movable reflecting mirrors are inserted in the optical paths to transfer the beams to the standard sample chamber.

Double beam spectrophotometer

An apparatus for measuring color transmissivities of a color separation prism P includes (where the color separation prism P receives a measurement light S on an incident path and emits three color lights Sr, Sg and Sb on three exit paths of different directions): a photomultiplier 21 and an integrating sphere I for measuring an intensity of light entering the integrating sphere I on an entrance path, where the entrance path is set detached from an extension of the incident path; a first movable mirror 9 located in one of four paths including an extension of the incident path and the three exit paths for reflecting the light on each path to the second movable mirror 10; and a second movable mirror 10 placed on the entrance path of the integrating sphere I (with the photomultiplier 21) and oriented in one of four directions for reflecting the light from the first movable mirror 9 to the integrating sphere I. Because the 100%-transmission light and the three color lights transmitted through the color separation prism P undergo the same optical history, absolute transmissivities of the color lights can be measured, and the two-beam method can be used since the integrating sphere I is fixed.

Transmissivity measuring apparatus for a color separation prism

An integrating sphere has two openings, at which light-receiving and light-emitting ends of an optical fiber sample are attached. A light-receiving opening is provided opposite one of these openings, and another light-receiving opening opposite from none of those other openings. A monochromatic light beam from a source such as a spectroscope is passed through a lens or the like to be made convergent and introduced into the integrating sphere through each of the light-receiving openings. The difference in the optical path length between the two measurements is entirely due to the presence or absence of the optical fiber sample, and the spectral transmissivity of the sample can be measured accurately.

Apparatus for measuring spectral transmissivity of optical fiber

A spectrophotometer of the type using a pulse motor to rotate a diffraction grating through a speed reducing mechanism has a capability of constructing a conversion table according to a program, by which table a rotation amount of the motor is converted to a corresponding wavelength of output light from a monochromator. The spectrophotometer is capable of designating a calibration mode in which an emission peak at a known wavelength of light from a light source is detected, a coefficient in a conversion equation is determined on the basis of the known wavelength of the emission peak and a rotation amount of the motor at a time when the emission peak is detected, and the determined coefficient is used to construct the conversion table which is then stored in a nonvolatile memory. In an analysis mode, a rotation amount of the motor is converted to a corresponding wavelength in accordance with the conversion table in the nonvolatile memory.

Method and apparatus for calibrating a spectrophotometer

An entrance slit and exit slit of a monochromator is shaped so that the width of the slits becomes smaller from the center towards the ends of their height, where the width is a dimension in the direction of the separation of the light in the monochromator. An example of such shape is rhombic. When the total amount of light emitted from the monochromator and the resolution of the monochromator are set to be the same, the efficiency of light in measuring small samples is increased and the ratio of stray light in the light emitted from the monochromator becomes smaller.

Monochromator

In quantitative analysis of a sample by using the spectrum thereof by means of a spectrophotometer, at a specific wavelength or in a specific wavelength range where a quantitative determination is to be conducted, wavelength scanning is temporarily stopped or its speed is slowed down so as to obtain spectral data from the sample, so that the accuracy of the data obtained is improved. In the wavelength range where no quantitative determination is to be conducted, the scanning operation is conducted at an ordinary relatively fast speed, so that the total time required for the analysis will not be lengthened.

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Kyoto, Japan

Tatsumi Sato