Blade driving device for use in cameras

• US 20050058444A1
• Filed: 09/15/2004
• Published: 03/17/2005
• Est. Priority Date: 09/17/2003
• Status: Active Grant

• Current Assignee: Nidec Copal Corporation (Nidec Corporation)
• Original Assignee: Nidec Copal Corporation (Nidec Corporation)
• Inventors: Watanabe, Nobuaki, Eguro, Tohru, Yamagishi, Shigeru
• Granted Patent: US 7,156,564 B2
• Time in Patent Office: Days
• US Class Current: 396/458
• CPC Class Codes: G03B 9/08 Shutters

Abstract

A blade driving device for use in cameras of the present invention includes a base plate having an exposure aperture, an ND filter blade that is supported rotatably around a supporting shaft on the base plate and is moved to a position withdrawn from the exposure aperture and a position facing the exposure aperture, and an electromagnetic actuator that drives the ND filter blade. This electromagnetic actuator includes a frame member joined to the base plate, a rotor which has a drive pin for exerting a driving force and rotates within a predetermined angle range with one end of which being supported to the frame member and the other end of which being supported to the base plate, and an exciting coil wound around the frame member and the base plate. Therefore, the structure of the electromagnetic actuator for driving a shutter blade, a diaphragm blade, an ND filter blade or the like can be simplified and reduced in cost, and this makes it possible to reduce the size and thickness of the device.

Claims

1. A blade driving device for use in cameras comprising:

a base plate having an exposure aperture;

a blade member supported rotatably around a supporting shaft on the base plate and moved to a position withdrawn from the exposure aperture and a position facing the exposure aperture; and

an electromagnetic actuator for driving the blade member, wherein

the electromagnetic actuator includes a frame member joined to the base plate, a rotor which has a drive pin that exerts a driving force to the blade member and rotates within a predetermined angle range with one end of which being supported to the frame member and the other end of which being supported to the base plate, and an exciting coil wound around the frame member and the base plate, and

the blade member is a shutter blade for opening and closing the exposure aperture, a diaphragm blade for stopping down the exposure aperture to a predetermined diameter, or an ND filter blade for reducing the amount of light by covering the exposure aperture.

2. The blade driving device for use in cameras according to claim 1, wherein the electromagnetic actuator includes a yoke provided outside the coil roughly coaxially with the rotor.

3. The blade driving device for use in cameras according to claim 1, wherein

the base plate is provided with two of the electromagnetic actuators, the shutter blade and the diaphragm blade,

one of the two electromagnetic actuators is formed so as to drive the shutter blade, and

the other one of the two electromagnetic actuators is formed so as to drive the diaphragm blade.

4. The blade driving device for use in cameras according to claim 1, wherein

the base plate is provided with two of the electromagnetic actuators, the shutter blade, and the ND filter blade,

one of the two electromagnetic actuators is formed so as to drive the shutter blade, and

the other one of the two electromagnetic actuators is formed so as to drive the ND filter blade.

5. The camera blade driving device for use in cameras according to claim 1, wherein

the base plate is provided with two of the electromagnetic actuators and two of the diaphragm blades having diameters different from each other,

one of the two electromagnetic actuators is formed so as to drive one of the two diaphragm blades, and

the other one of the two electromagnetic actuators is formed so as to drive the other one of the two diaphragm blades.

6. The blade driving device for use in cameras according to claim 1, wherein

the base plate is provided with two of the electromagnetic actuators and two of the ND filter blades having densities different from each other,

one of the two electromagnetic actuators is formed so as to drive one of the two ND filter blades, and

the other one of the two electromagnetic actuators is formed so as to drive the other one of the two ND filter blades.

7. The blade driving device for use in cameras according to claim 1, wherein

the base plate is provided with two of the electromagnetic actuators, the diaphragm blade, and the ND filter blade,

one of the two electromagnetic actuators is formed so as to drive the diaphragm blade, and

the other one of the two electromagnetic actuators is formed so as to drive the ND filter blade.

8. The blade driving device for use in cameras according to claim 1, wherein

the ND filter blade includes a pair of blades that define an aperture with a predetermined diameter and an ND filter sandwiched between and joined to the pair of blades.

9. The blade driving device for use in cameras according to claim 1, wherein

the ND filter blade includes a blade that defines an aperture with a predetermined diameter and an ND filter joined to one side surface of the blade.

10. The blade driving device for use in cameras according to claim 9, wherein

the ND filter blade is formed so that an opposite side surface of the ND filter joined to the blade is supported by a guide rail provided on the base plate.