Light intensity control device, imaging device and light intensity control method

摘要

A light intensity control device includes a fixed opening 261, an aperture stop part 26 for controlling a light flux of incident light, a light intensity aperture part 24 for changing the size of an opening by moving a plurality of aperture blades to limit a light intensity of transmitted light and a ND filter 25 having a transparent area 253 and a light blocking area 254, which is arranged to be movable between a first light blocking state where the transparent area 253 faces the fixed opening 261 of the aperture stop part 26 and a second light blocking state where the light blocking area 254 faces the fixed opening. The moving of the ND filter 25 is carried out when the opening area of the light intensity aperture part 24 is a maximum.

主权项

1. A light intensity control device comprising:
an aperture stop part provided with an opening part having a of first opening area thereby controlling flux of incident light to a predetermined size; a light extinction part having a first area whose transmissivity for the incident light is more than a first value and a second area whose transmissivity for the incident light is a second value smaller than the first value, the light extinction part being adapted to be movable between its first blocking state where the first area covers the opening part completely and a second light blocking state a second light blocking state where the second area covers the opening part completely; and a light intensity aperture part having a plurality of movable aperture blades to further limit a light intensity of light transmitted through the opening part by moving the plurality of aperture blades so that the size of an opening defined by the aperture blades against the opening part is changed from the first opening area to a second opening area smaller than the first opening area, wherein:
the moving of the light extinction part and the moving of the plurality of aperture blades are carried out independently of each other,the light extinction part is movable between the first light blocking state and the second light blocking state under a condition that the size of the opening defined by the aperture blades is equal to or larger than the size of the opening part, andthe plurality of aperture blades are movable under a condition that the light extinction part has the second light blocking state.