| 摘要 |
PURPOSE:To obtain a wavelength feed mechanism suitable for a low cost type spectrophotometer relatively rough in a wavelength feed step and low in accuracy request, by forcibly moving the sign bar provided to the rotary shaft of a diffraction lattice in a protruded state by an impact member connecting the non-extensible flexible member wound around a pulley. CONSTITUTION:A steel belt 3 is wound around a pulley 2 fitted to the shaft of a stepping motor 1 and both ends thereof the fixed to an impact member 4 which is held to a guide 5. A sign bar 8 fixed to the rotary stand 7 of diffraction lattice 6 is forcibly moved by the member 4 and each phase exciting current of a motor 1 is stepwise changed so as to perform so called micro-stepping driving finely dividing the inherent stepping angle of the motor 1. As a result, the error on a mechanism is caused by the out of roundness or eccentricity of the pulley but the enhancement of the accuracy of the pulley is easy as compared with the engineering work of a feed screw mechanism and the title mechanism can be inexpensively obtained as compared with a feed screw type sign bar mechanism.
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