Hitachi, Ltd.

Nobuo Akitomo

Shigeo Tohyama

Isao Nemoto

Takeo Murakoshi

Calibrating apparatus in a monochromator

A spectro-photometer having a calibration mechanism and a wavelength-range changeover mechanism is disclosed which is equipped with an operation panel for setting measuring frequencies and function modes, is controlled by a microcomputer to be subjected to the calibration and the changeover of wavelength range in a predetermined order, conducts a predetermined arithmetic operation on the basis of photometric values measured by the spectro-photometer, and further comprises two display elements mounted on the operation panel for performing the following display operation in accordance with a command from the microcomputer. That is, in the calibration period, a code showing that the spectro-photometer is now subjected to calibration, is displayed on one of the display elements, and the number of remaining check items is displayed on the other display element. While, in the wavelength-range changeover period, a code showing that the spectro-photometer is subjected to the wave-length changeover operation, is displayed on one display element, and a waiting time till the termination of wavelength-range changeover operation is displayed on the other display element.

Spectro-photometer with arithmetic and control unit

In a spectrophotometer including a housing, an optical system mounted in the housing and a specimen chamber formed by partitioning a part of the housing for mounting therein a sample cell, the specimen chamber is formed with an opening through which the sample cell is mounted and dismounted and a cover plate is mounted so as to be slidably movable between a closing position where the opening of the chamber is wholly covered by the cover plate and an opening position where the specimen chamber is accessible from outside of the housing.

Spectrophotometer

A recording sheet is successively fed in the abscissa direction by means of a sprocket. The recording sheet is previously printed with ruled lines with a predetermined inter-line space in the ordinate direction thereof. The sprocket is driven by a pulse motor. Displacement of the recording sheet from one to the next ruled line corresponds to the number of pulses supplied to the pulse motor. Before the beginning of the recording, a ruled line on the recording sheet is brought into positional coincidence with the recording pen. During the movement of the recording sheet after the recording operation having been started, a counter counts the pulses supplied to the pulse motor and is reset every time when the number of the pulses corresponding to the inter-line space has been attained. Upon termination of the recording, the contents in the counter represents the position of a recording pen relative to a certain ruled line. On the basis of the contents in the counter, the recording sheet is automatically fed in the abscissa direction. Upon occurrence of coincidence between the certain ruled line and the recording pen position, the feeding of the recording sheet is stopped. In this manner, the recording pen is always positioned in alignment with one of the ruled lines on the recording sheet at the beginning of the succeeding recording operation, requiring no manipulatability for the positional alignment.

Recording system with inter-line space positioning means

In the double-beam spectrophotometer, two light beams, a reference beam and a sample beam, are used. Optical signals in the light beams are converted into electrical signals. The magnitudes of a reference signal and a sample signal are compared. A voltage to be applied to a photoelectric converting means is adjusted on the basis of the difference signal between the larger signal of the compared signals and a reference voltage so that the magnitude of the larger signal is substantially constant. The spectrum displayed by a recorder is obtained by the ratio of the reference signal to the sample signal. Since the larger signal is controlled to be substantially constant, when the sample signal is larger than the reference signal as in the case of a difference spectrum, the photoelectric converting means is not saturated and a wide photometering range is secured.

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Katsuta, Japan

Nobuo Akitomo