US 4,897,681 AGranted

Exposure amount adjusting device

AssigneesCanon Kabushiki Kaisha, Canon Denshi Kabushiki Kaisha

InventorsHiroshi Yamamoto, Tadashi Arai, Akira Kurosawa

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Abstract

An exposure amount adjusting device comprises a stepping motor which serves as a drive source and includes a rotor, a stator and an exciting coil; and an exposure amount adjusting arrangement which is driven by the stepping motor. The exposure amount adjusting arrangement includes a fixed member having an aperture to give a passage to light, a positioning member and a bearing which are arranged away from the aperture, the positioning member determining the position of the stator, the bearing rotatably carrying the stator; a rotary member which has another light passing aperture and is arranged to be driven by the rotor; and light shielding blades which are swingably carried by both the fixed and rotary members and arranged to vary their aperture shielding areas according to a rotating position of the rotary member.

Claims6

Dependent claims

An exposure amount adjusting device comprising:

a stepping motor which serves as a drive source, said stepping motor including a rotor, a stator and an exciting coil;
and
exposure amount adjusting means which is arranged to be driven by said stepping motor, said exposure amount adjusting means including:
a fixed member having an aperture arranged to provide a passage for a light beam, said fixed member being provided with a positioning member and a bearing which are arranged away from said aperture, said positioning member determining the position of said stator, said bearing rotatably carrying said rotor,
a rotary member which also has a light flux passing aperture, said rotary member being arranged to be driven by said rotor, and
a plurality of light shielding blades which are swingably carried by said fixed member and said rotary member, said plurality of light shielding blades being arranged to vary light shielding areas thereof for said two apertures in response to a rotating position of said rotary member.

3 more elements

Dependencies are inferred from the claim text.