The optical axis of observation light irradiating the luminous flux which

摘要

PROBLEM TO BE SOLVED: To provide a biological microscope capable of light-view observation and dark-view observation from a low magnification to a high magnification in the wide range of view field with sufficient brightness and to provide a dark-view field lighting system.;SOLUTION: The biological microscope has a light irradiation angle varying means for varying, by the rotation of a ring frame 9, the angle of the irradiation of a luminous flux emitted to a specimen 5 from a plurality of light emitting diodes 10 concentrically disposed on the inside of the hollow ring frame 9 helically fitted in a base 8. The dark-field lighting system is used for the biological microscope. The dark-field lighting system is capable of dark-field illumination over the entire range of view field from a low magnification to a high magnification according to the necessity of observation. The dark-field lighting system is capable of light-field illumination or/and dark-field illumination.;COPYRIGHT: (C)2006,JPO&NCIPI