Imaging apparatus

Patent metadata

Field	Value
Publication number	US-9335560-B2
Application number	US-201514607689-A
Country	US
Kind code	B2
Filing date	Jan 28, 2015
Priority date	Jan 30, 2014
Publication date	May 10, 2016
Grant date	May 10, 2016

Abstract

An imaging apparatus includes a front lens group having a front lens element and a reflector; a support member supporting the reflector; a support mechanism supporting the movable frame, supporting the front lens element, to spherically swing about a center positioned on an extension of the front lens element optical axis behind a reflection surface of the reflector; and a permanent magnet and a coil as an actuator which performs image stabilization by driving the movable frame in response to vibrations to spherically swing the movable frame. The permanent magnet and the coil planarly extend parallel to tangent planes, tangent to imaginary spheres centered about the center, respectively. Any normal to the tangent plane of the permanent magnet is inclined to the optical axis of the front lens element such that a distance between the normal and the optical axis increases in a direction toward the object side.

First claim

What is claimed is:

1. An imaging apparatus comprising:
a front lens group which constitutes part of an imaging optical system of said imaging apparatus and includes at least one front lens element and a reflector, in that order from an object side, wherein said reflector includes a reflection surface which reflects light rays, exiting from said front lens element, toward a different direction, and wherein said imaging apparatus performs an image-stabilizing operation by driving said front lens element in response to vibrations applied to said imaging optical system in order to reduce image shake on said image plane;
at least one rear lens group which constitutes another part of said imaging optical system and is positioned closer to an image plane than said front lens group;
a movable frame which holds said front lens element;
a support member which supports at least said reflector and is immovable relative to an optical axis of said front lens element in a reference state in which said imaging apparatus does not drive said front lens element when said image-stabilizing operation is not performed;
a support mechanism which supports said movable frame in a manner to allow said movable frame to spherically swing along an imaginary spherical surface about a spherical-swinging center which is positioned on an extension of said optical axis, of said front lens element, extending behind an underside of said reflection surface of said reflector; and
an actuator which applies a driving force to said movable frame in response to the vibrations applied to said imaging optical system to make said movable frame spherically swing about said spherical-swinging center,
wherein said actuator comprises a voice coil motor including a permanent magnet and a coil, one of said permanent magnet and said coil being fixedly held by said movable frame and the other of said permanent magnet and said coil being fixedly held by said support member,
wherein said permanent magnet planarly extends in a direction parallel to a first tangent plane that is tangent to a first imaginary sphere, centered about said spherical-swinging center,
wherein said coil is formed by winding wire to lie in a second tangent plane that is tangent to a second imaginary sphere about said spherical-swinging center, said coil extending planarly in a direction parallel to said second tangent plane,
wherein any normal to said first tangent plane is nonparallel to said optical axis of said front lens element and intersects said optical axis of said front lens element or an extension line thereof, and
wherein any half line, which extends toward said first tangent plane in a direction parallel to said any normal from an intersecting point between said normal and said optical axis or said extension line thereof, has an inclination with respect to said optical axis of said front lens element such that a distance between said half line and said optical axis of said front lens element increases in a direction toward said object side.

2. The imaging apparatus according to claim 1 , wherein an angle of inclination of said half line relative to a half line that extends toward said object side in a direction parallel to said optical axis of said front lens element from said intersecting point falls within a range from 40 degrees to 80 degrees.

3. The imaging apparatus according to claim 1 , wherein said first tangent plane and said second tangent plane are substantially parallel to each other.

4. The imaging apparatus according to claim 1 , wherein, when two intersecting points at which an imaginary spherical surface of said first imaginary sphere intersects with said optical axis of said front lens element and said extension line thereof are defined as poles of said first imaginary sphere, any circular arc on said imaginary spherical surface of said first imaginary sphere which connects said poles of said first imaginary sphere is defined as a meridian line, any circular arc on said imaginary spherical surface of said first imaginary sphere which is orthogonal to said meridian line is defined as a latitude line, α1 designates an intersecting point between said first tangent plane and a straight line which passes through a center of an outer profile of said permanent magnet and is parallel to said any normal to said first tangent plane, and β1 designates a contacting point between said first imaginary sphere and said first tangent plane in a plane which passes through said intersecting point α1 and extends through said meridian line,
said imaging apparatus satisfies the following condition:
0≦γ1<δ1×0.2

wherein γ1 designates a distance between said intersecting point α1 and said contacting point β1 along said first tangent plane and on a plane extending through said meridian line, and
δ1 designates a size of said permanent magnet along said first tangent plane and on a plane extending through said meridian line.

5. The imaging apparatus according to claim 4 ,
wherein said distance γ1 is equal to zero.

6. The imaging apparatus according to claim 1 , wherein, when two intersecting points at which an imaginary spherical surface of said first imaginary sphere intersects with said optical axis of said front lens element and said extension line thereof are defined as poles of said first imaginary sphere, any circular arc on said imaginary spherical surface of said first imaginary sphere which connects said poles of said first imaginary sphere is defined as a meridian line, any circular arc on said imaginary spherical surface of said first imaginary sphere which is orthogonal to said meridian line is defined as a latitude line, α2 designates an intersecting point between said first tangent plane and a straight line which passes through a center of an outer profile of said permanent magnet and is parallel to said any normal to said first tangent plane, and β2 designates a contacting point between said first imaginary sphere and said first tangent plane in a plane which passes through said intersecting point α2 and extends through said latitude line,
said imaging apparatus satisfies the following condition:
0γ2<δ2×0.2

wherein γ2 designates a distance between said intersecting point α2 and said contacting point β2 along said first tangent plane and on a plane extending through said latitude line, and
δ2 designates a size of said permanent magnet along said first tangent plane and on a plane extending through said latitude line.

7. The imaging apparatus according to claim 6 , wherein said distance γ2 is equal to zero.

8. The imaging apparatus according to claim 1 , wherein said permanent magnet is fixedly held by said movable frame,
wherein said coil is fixedly held by said support member, and
wherein said permanent magnet is positioned closer to said spherical-swinging center than said coil in a radial direction of said first imaginary sphere and said second imaginary sphere.

9. The imaging apparatus according to claim 8 , further comprising a sensor which senses variations in magnetic field to detect a position of said movable frame,
wherein said sensor, said permanent magnet and said coil are aligned in said radial direction in that order from said spherical-swinging center side.

10. The imaging apparatus according to claim 1 , wherein said permanent magnet comprises two permanent magnets which are arranged at different positions in a direction along an imaginary circle about said optical axis of said front lens element.

11. The imaging apparatus according to claim 1 , wherein a magnetic-pole boundary line of said permanent magnet is in contact with an imaginary circle about said optical axis of said front lens element as viewed in a direction

Assignees

• Hoya Corp

Inventors

• Nomura Hiroshi
• Suzuka Shinya
• Morinaga Takahiro

Classifications

• H04N23/55

  Optical parts specially adapted for electronic image sensors; Mounting thereof · CPC title

• H04N23/68

  for stable pick-up of the scene, e.g. compensating for camera body vibrations · CPC title

• H04N23/687

  by shifting the lens or sensor position · CPC title

• H04N5/23287

  Electricity · mapped topic

• H04N5/2254

  Electricity · mapped topic