Lens drive system
AssigneePENTAX Corporation
InventorYoshihiro Yamazaki
Life of this patent
Estimating the term…
Abstract
A lens drive system includes a lens frame having a lens element; a nut member secured to the lens frame, and which are both movable in an optical axis direction without rotating; a feed screw shaft having a male thread portion and a non-threaded portion, the male thread portion being engaged with a screw hole of the nut member; a motor for rotating the feed screw shaft; and a biasing member for biasing the nut member in a first direction toward the male thread portion. When the feed screw shaft is rotated to move the nut member and the lens frame in a second direction toward the non-thread portion, the female thread portion is disengaged from the male thread portion to move onto the non-threaded portion before the lens frame or the nut member abuts against an element of the lens drive system and stops thereby.
Claims27
A lens drive system comprising:
- a lens frame having at least one lens element;
- a nut member which is secured to said lens frame, said lens frame and said nut member being movable in an optical axis direction without rotating relative to a base of said lens drive system, the direction of a screw hole of said nut member being parallel with the optical axis;
- a feed screw shaft having a male thread portion and a non-threaded portion, said male thread portion being engaged with a screw hole of said nut member so that said male thread portion is engaged with a female thread portion formed on an inner peripheral surface of said screw hole, a diameter of said non-threaded portion being smaller than an inner diameter of said screw hole;
- a motor for rotating said feed screw shaft;
- and
- a biasing member for biasing said nut member in a first direction from said non-thread portion toward said male thread portion;
- wherein, when said feed screw shaft is rotated in a predetermined rotational direction by said motor to move said nut member and said lens frame in a second direction from said male thread portion toward said non-thread portion, said female thread portion is disengaged from said male thread portion to move onto said non-threaded portion before at least one of said lens frame and said nut member abuts against an element of said lens drive system other than said lens frame and said nut member and stops thereby.
A lens drive system comprising:
- a lens frame having at least one lens element;
- a nut member which is secured to said lens frame, said lens frame and said nut member being movable in an optical axis direction without rotating relative to a base of said lens drive system, the direction of a screw hole of said nut member being parallel with the optical axis;
- a feed screw shaft having a male thread portion and a non-threaded portion, said male thread portion being engaged with a screw hole of said nut member so that said male thread portion is engaged with a female thread portion formed on an inner peripheral surface of said screw hole, a diameter of said non-threaded portion being smaller than an inner diameter of said screw hole;
- a motor for rotating said feed screw shaft;
- and
- a biasing member for biasing said lens frame in a first direction from said non-thread portion toward said male thread portion;
- wherein, when said feed screw shaft is rotated in a predetermined rotational direction by said motor to move said lens frame in a second direction from said male thread portion toward said non-thread portion, said female thread portion is disengaged from said male thread portion to move onto said non-threaded portion before at least one of said lens frame and said nut member abuts against an element of said lens drive system other than said lens frame and said nut member and stops thereby.
A lens barrel including a photographing optical system having of a plurality of lens groups, said plurality of lens groups including a focusing lens group, said lens barrel comprising:
- a linear guide mechanism for linearly guiding said focusing lens group in an optical axis direction without making said focusing lens group rotate relative to a stationary barrel of said lens barrel;
- a nut member having a screw hole which is guided linearly in said optical axis direction without rotating relative to said stationary barrel via said linear guiding mechanism;
- a feed screw shaft having a male thread portion and a non-threaded portion, said feed screw shaft being inserted in said screw hole so that said male thread portion is engaged with a female thread portion formed on an inner peripheral surface of said screw hole, a diameter of said non-threaded portion being smaller than an inner diameter of said screw hole;
- a motor for rotating said feed screw shaft;
- a lens frame which holds at least one lens element and is movable together with said nut member;
- and
- a biasing member for biasing said nut member in a first direction from said non-thread portion toward said male thread portion;
- wherein, when said feed screw shaft is rotated in a predetermined rotational direction by said motor to move said nut member and said lens frame in a second direction from said male thread portion toward said non-thread portion, said female thread portion is disengaged from said male thread portion to move onto said non-threaded portion.
Dependencies are inferred from the claim text.