Photography – Camera shake sensing – Having stabilization system
Reexamination Certificate
2002-01-17
2004-05-11
Adams, Russell (Department: 2851)
Photography
Camera shake sensing
Having stabilization system
C348S208990
Reexamination Certificate
active
06735383
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a vibration correction apparatus, a lens apparatus using the vibration correction apparatus, and an optical apparatus using the lens apparatus.
2. Related Background Art
In current cameras, all important operations for photography, e.g., exposure determination and focusing, are automated. For this reason, even unskilled photographers rarely make photographic errors.
In addition, recently, systems for preventing hand vibrations from being applied to cameras have been studied, thus almost eliminating factors that cause photographers to make photographic errors.
A system for preventing hand vibrations will be briefly described below.
In general, hand vibrations applied to a camera at the time of photography have a frequency of 1 to 12 Hz. According to the basic idea for taking a picture without image blur even with such hand vibrations at the time of shutter release, the vibrations of the camera due to the above hand vibrations must be detected, and the correction lens must be displaced in accordance with the detection value. In order to allow a photographer to take a picture without image blur even with vibrations produced in the camera, the vibrations of the camera must be accurately detected first, and then optical axis displacement due to hand vibrations must be corrected.
Detection of such vibrations (camera vibrations), according to its principle, can be performed by equipping the camera with a vibration sensor for detecting an angular acceleration, angular velocity, angular displacement, or the like and a vibration detection means for electrically or mechanically integrating output signals from the vibration sensor to output an angular displacement. A correction optical apparatus for decentering the photography optical axis is driven on the basis of this detection information, thereby suppressing vibrations.
A system having a vibration correction function will be briefly described below with reference to FIG.
5
.
FIG. 5
shows a system for suppressing image blur caused by vertical camera vibration
81
p
and horizontal camera vibration
81
y
in the directions indicated by arrows
81
. In this case, this system is provided for the exchangeable photographing lens of a single-lens reflex camera.
Referring to
FIG. 5
, this camera includes a lens barrel
82
, vibration sensors
83
p
and
83
y
for respectively detecting vertical camera vibration and horizontal camera vibration in vibration detection directions
84
p
and
84
y,
and a vibration correction apparatus
85
(having coils
87
p
and
87
y
each serving to apply thrust to the vibration correction apparatus
85
and position sensors
86
p
and
86
y
for detecting the position of the vibration correction apparatus
85
). A position control loop is formed in the vibration correction apparatus
85
, which is driven in accordance with a target value based on outputs from the vibration sensors
83
p
and
83
y,
thereby ensuring stability of an image surface
88
.
In general, a photographer uses a camera in all positions, e.g., upward and downward positions, at the time of photography. Assume that a photographing lens including an image blur correction apparatus made up of a vibration correction apparatus and vibration sensors like those shown in
FIG. 5
is mounted in a camera body, and photography is performed. In this case, since a tilt occurs in the optical axis direction due to the weight of the vibration prevention optical element (correction lens), the optical element must be decentered in the optical axis direction by a charge spring or the like.
The friction on the contact surface due to the charged state (i.e., the decentered state) increases to result in a deterioration in the movement of the optical element.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an image blur correction apparatus which can improve a vibration correction effect by performing drive so as to reduce the influence of a frictional force in driving a correction lens.
In order to achieve the above object, according to the present invention, there is provided a vibration correction apparatus comprising
a vibration detection unit which detects a vibration,
a signal processing unit which performs signal processing for a vibration detection signal output from the vibration detection unit,
a vibration correction unit which corrects an image movement caused by the vibration, on the basis of a drive signal output from the signal processing unit, and
a controller which controls drive of the vibration correction unit,
wherein the controller corrects the drive signal from the signal processing unit by using a predetermined correction value corresponding to a drive direction of the vibration correction unit, and controls drive of the vibration correction unit by using the corrected drive signal.
In order to achieve the above object, according to the present invention, there is provided a vibration correction apparatus comprising
a vibration detection unit which detects a vibration,
a signal processing unit which performs signal processing for a vibration detection signal output from the vibration detection unit,
a vibration correction unit which corrects an image movement caused by the vibration, on the basis of a drive signal output from the signal processing unit, and
a controller which controls drive of the vibration correction unit,
wherein the controller corrects the drive signal from the signal processing unit by using a predetermined correction value corresponding to a polarity of a vibration detection signal output from the vibration detection unit, and controls drive of the vibration correction unit by using the corrected drive signal.
In order to achieve the above object, according to the present invention, there is provided an interchangeable lens apparatus which is detachably mounted on an image pickup apparatus, comprising
a vibration detection unit which detects a vibration,
a signal processing unit which performs signal processing for a vibration detection signal output from the vibration detection unit,
a vibration correction optical unit which corrects an image movement caused by the vibration, on the basis of a drive signal output from the signal processing unit, the vibration correction optical unit being mounted in a main body of the interchangeable lens apparatus and capable of moving in a direction perpendicular to an optical axis of the interchangeable lens apparatus, and
a controller which controls drive of the vibration correction unit,
wherein the controller corrects the drive signal from the signal processing unit by using a predetermined correction value corresponding to a drive direction of the vibration correction optical unit, and controls drive of the vibration correction optical unit by using the corrected drive signal.
In order to achieve the above object, according to the present invention, there is provided an interchangeable lens apparatus which is detachably mounted on an image pickup apparatus, comprising
a vibration detection unit which detects a vibration,
a signal processing unit which performs signal processing for a vibration detection signal output from the vibration detection unit,
a vibration correction optical unit which corrects an image movement caused by the vibration, on the basis of a drive signal output from the signal processing unit, the vibration correction optical unit being mounted in a main body of the interchangeable lens apparatus and capable of moving in a direction perpendicular to an optical axis of the interchangeable lens apparatus, and
a controller which controls drive of the vibration correction unit,
wherein the controller corrects the drive signal from the signal processing unit by using a predetermined correction value corresponding to a polarity of a vibration detection signal output from the vibration detection unit, and controls drive of the vibration correction optical unit by using the corrected drive signal.
In order to achieve the above object, according t
Adams Russell
Smith Arthur A
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