Photography – Camera shake sensing – Having stabilization system
Reexamination Certificate
2001-04-02
2002-10-22
Perkey, W. B. (Department: 2851)
Photography
Camera shake sensing
Having stabilization system
Reexamination Certificate
active
06470147
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to image blur correction means for correcting image blur attributable to vibration applied to an image pickup apparatus on the basis of the result of the detection by vibration detecting means for detecting the state of the aforementioned vibration, and an image pickup apparatus having the image blur correction means.
The invention further relates to improvements in the image blur correction apparatus of a camera and an interchangeable lens with the image blur correction apparatus.
2. Related Background Art
In present-day cameras, operations important to photographing such as exposure determination and focusing, are all automated; therefore, even a person unskilled in camera operation has very little possibility of causing a failure in photographing.
Also, recently, a system for preventing hand vibration applied to a camera has been studied and factors for inducing an error in the photographing by a photographer have become almost null.
The system for preventing hand vibration will be briefly described here.
The hand vibration of a camera during photographing is usually vibration of a frequency of 1-12 Hz, but as a basic idea for enabling a photograph free of image blur to be taken even if such hand vibration is caused at a point of time when the shutter is released, the vibration of the camera by the above-mentioned hand vibration must be detected and a correction lens must be displaced in conformity with the detected value. Accordingly, to enable a photograph free of image blur to be taken even if the vibration of the camera is caused, firstly it is necessary to detect the vibration of the camera accurately, and secondly it is necessary to correct the displacement of the optical axis caused by the hand vibration.
Theoretically speaking, the detection of this vibration (camera vibration) can be effected by carrying on a camera a vibration sensor for detecting angular acceleration, angular velocity, angular displacement, etc., and means for electrically or mechanically integrating the output signal of the vibration sensor and outputting angular displacement. Then, a correction optical system for making a photographing optical axis eccentric is driven on the basis of this detected information and the suppression of image blur is effected.
Here, the epitome of a vibration preventing system using a vibration detecting apparatus will be described with reference to
FIG. 10
of the accompanying drawings.
FIG. 10
shows a system for suppressing image blur attributable to camera pitch vibration
81
p
and to camera yaw vibration
81
y,
in the direction of arrows
81
, and shows a case where an image blur correction apparatus is provided in the interchangeable lens of a single-lens reflex camera.
In
FIG. 10
, the reference numeral
82
designates a lens barrel, and the reference characters
89
a,
89
b,
89
c
and
89
d
denote photographing optical systems which form the image of an object, not shown, on an image plane
88
. The reference characters
83
p
and
83
y
designate vibration detecting apparatus for detecting camera pitch vibration and camera yaw vibration, respectively, and their respective vibration detecting directions are indicated by
84
p
and
84
y.
The reference numeral
85
denotes a correction optical system (
87
p
and
87
y
designate coils for giving thrust to the correction optical system
85
, and
86
p
and
86
y
denote position detecting elements for detecting the position of the correction optical system
85
), and the correction optical system
85
is provided with a position control loop, and is driven with the outputs of the vibration detecting apparatuses
83
p
and
83
y
as target values, and secures the stability on the image plane
88
.
Also, although reduced in accuracy, the detection of the position of the correction optical system
85
is abolished to thereby reduce the cost, and vibration correction is also possible by an open control technique which does not provide the position control loop, but effects vibration correction control by only a vibration amount detected.
FIG. 11
of the accompanying drawings is an exploded perspective view showing an example of an image blur correction apparatus using the open control.
In
FIG. 11
, the reference numeral
1
designates a support frame for holding a correction lens, the reference numeral
2
denotes a ground plate for holding the support frame
1
, the reference numeral
3
designates a first yoke which is a magnetic member fixed to the ground plate
2
by screws or the like, not shown, and the reference numeral
4
denotes a winding coil fixed to the support frame
1
. The reference numeral
5
designates a second yoke which is a magnetic member fixed to the ground plate
2
by screws or the like, not shown, so as to sandwich the support frame
1
between it and the first yoke
3
, the reference numeral
6
denotes two permanent magnets magnetically attracted and fixed to the second yoke
5
and provided with their positions deviated by about 90° from each other. The reference characters
7
a
-
7
c
designate shift pins each having one end thereof forced into the support frame
1
and the other end thereof inserted in a slot
2
a
formed in the ground plate
2
, and radially provided about the optical axis at three locations equally divided into approximately 120° about the optical axis. The reference characters
8
a
-
8
d
denote springs for resiliently supporting the support frame
1
relative to the ground plate
2
, and each of the springs
8
a
-
8
d
has one end thereof positioned by a projection
1
a
provided on the support frame
1
and has the other end thereof positioned by a projection
2
b
provided on the ground plate
2
, and the springs
8
a
-
8
d
are provided at four locations equally divided into approximately 90° about the optical axis. The projections
1
a
and the projections
2
a
radially protrude about the optical axis and are provided so as to be opposed to each other on the same straight line and thus, the springs
8
(
8
a,
8
b,
8
c,
8
d
) are also radially disposed about the optical axis.
The assembling procedure is such that the first yoke
3
is first fixed to the ground plate
2
with screws or the like inserted into the holes thereof. Next, projections provided on the bobbin, not shown, of the winding coil
4
are inserted into holes formed in the support frame
1
, and the winding coil
4
is adhesively or otherwise fixed. Then, the shift pins
7
are forced into holes formed in the support frame
1
through the slots
2
a
formed in the ground plate
2
. Thereby the support frame
1
has its movement in the direction of the optical axis regulated relative to the ground plate
2
, but becomes movable except in the direction of the optical axis. Next, one end of each spring
8
is mounted on the projection
1
a
provided on the support frame
1
and the other end is mounted on the projection
2
b
provided on the ground plate
2
. Thereby the support frame
1
is held substantially about the optical axis. Next, the permanent magnets
6
are magnetically attracted and fixed to the second yoke
5
. Lastly, the second yoke
5
is fixed to the ground plate
2
by screws or the like so as to sandwich the support frame
1
between it and the first yoke
3
.
The permanent magnets
6
and the winding coil
4
are disposed so as to be opposed to each other. Thereby a conventional closed magnetic circuit is formed between the first yoke
3
and the permanent magnets
6
because the second yoke
5
is a magnetic member, and the winding coil
4
provided in this closed magnetic circuit and fixed to the support frame
1
is electrically energized to thereby produce thrust and drive the support frame
1
by any stroke. Also, when the winding coil
4
is not electrically energized, the support frame
1
is held substantially at the central position by the springs
8
, and since the springs
8
are provided at four locations equally divided into approximately 90°, the performance will not change
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Perkey W. B.
LandOfFree
Image blur correction apparatus and image pickup apparatus... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Image blur correction apparatus and image pickup apparatus..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Image blur correction apparatus and image pickup apparatus... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2942881