Title:
DIAPHRAGM DEVICE FOR PHOTOGRAPHIC LENS
Document Type and Number:
Japanese Patent JP3726436
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To reduce the influence of diffraction by a transparent part made minimum at an intermediate aperture and to miniaturize the device.
SOLUTION: The diaphragm device is provided with two aperture blades 3 and 4 and a neutral density(ND) filter holding member 5 to which a first ND filter 22 is attached. The ND filter holding member 5 is provided to move in the same direction as that of one aperture blade 3 located in a state that it holds the other aperture blade 4, in an optical axial direction and a second ND filter 23 is attached to cover a part of the aperture diameter forming notch 14 of one aperture blade is attached thereto, so that the area for covering an aperture 30 of the first ND filter 22 is larger than that of the second filter 23 and the displacement of the first ND filter caused by a change in aperture diameter is larger than that of the second ND filter.
Inventors:
Yusuke Nanjo
Kunio Nakazato
Kunio Nakazato
Application Number:
JP22478897A
Publication Date:
December 14, 2005
Filing Date:
August 21, 1997
Export Citation:
Assignee:
ソニー株式会社
International Classes:
G02B5/00; G03B9/02; G03B9/06; (IPC1-7): G03B9/06; G02B5/00; G03B9/02
Domestic Patent References:
| JP5281592A | ||||
| JP8179397A | ||||
| JP8234268A |
Attorney, Agent or Firm:
Yuji Komatsu