Photography – Camera shake sensing – Having stabilization system
Reexamination Certificate
1998-02-18
2004-03-09
Adams, Russell (Department: 2851)
Photography
Camera shake sensing
Having stabilization system
Reexamination Certificate
active
06704501
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an image blur prevention apparatus for preventing an image blur caused by hand vibration or the like in a camera, optical equipment, or the like.
2. Related Background Art
In currently available cameras, all operations important to take a picture, e.g., exposure and focus control, are automatically determined. Therefore, even an unskilled user rarely fails in a photographing operation.
Further, since a system for preventing influence of hand vibration of a photographer on a camera has recently been studied, there are few or no factors causing a failure in a photographing operation by the photographer.
The system for preventing hand vibration will be described here in brief.
In general, hand vibration of the photographer using the camera in a photographing operation falls within a vibration range of 1 Hz to 12 Hz. According to a basic concept of taking a picture without any image blur even when hand vibration is created by the photographer in a shutter release operation of the camera, it is necessary to detect camera vibration (fluctuation) caused by the above hand vibration and displace a correction lens in accordance with the detection value. In order to achieve the above object (i.e., to take a picture without any image blur even with camera vibration), first of all, camera vibration must be accurately detected, and secondly, a change in optical axis due to hand vibration must be corrected.
In principle, detection of this vibration (camera vibration) can be performed by mounting a vibration sensor and a camera vibration detecting means in a camera. The vibration sensor detects an angular acceleration, an angular velocity, an angular displacement, and the like. The camera vibration detecting means electrically or mechanically integrates output signals from the sensor to output an angular displacement. Image blur suppression can then be performed by driving a correction optical apparatus for offsetting the photographic optical axis on the basis of the detection information.
A blur prevention system using a vibration detecting means will be described here with reference to FIG.
38
.
FIG. 38
shows an example of a system for suppressing an image blur resulting from vertical camera vibration (fluctuation)
81
p
and lateral camera vibration (fluctuation)
81
y
in directions
81
indicated by the arrows in FIG.
38
.
Referring to
FIG. 38
, the system includes a lens barrel
82
and vibration detecting means
83
p
and
83
y
for respectively detecting a vertical camera vibration and a lateral camera vibration in vibration detecting directions
84
p
and
84
y
. It also includes a correction optical apparatus
85
(coils
87
p
and
87
y
for giving a thrust to the correction optical apparatus, and position detection elements
86
p
and
86
y
for detecting the position of the correction optical apparatus). The correction optical apparatus
85
has a position control loop to be described later. The correction optical apparatus
85
is driven by using outputs from the vibration detecting means
83
p
and
83
y
as target values, thereby stabilizing an image surface
88
.
FIG. 39
is an exploded perspective view showing the structure of a suitable blur correction apparatus (as will be described later in detail, which is constructed of a correction means, means for supporting and engaging the correction means, and the like). The structure will be described below with reference to
FIGS. 39
to
48
.
Three backside lugs (one lug is hidden) of a base plate
71
(also shown in an enlarged view of
FIG. 42
) are fitted or inserted in a lens barrel, not shown, and a known barrel roller or the like is fixed to the lens barrel by tightening screws into holes
71
b.
A bright-plated second yoke
72
as a magnetic material is fixed to the base plate
71
by tightening screws into holes
71
c
through holes
72
a
. Permanent magnets (shifting magnets)
73
such as neodymium magnets are magnetically absorbed on the second yoke
72
. The permanent magnets
73
are respectively magnetized in directions indicated by the arrows
73
a
in FIG.
39
.
A correction lens
74
is fixed to a support frame
75
(see an enlarged view of
FIG. 43
) by means of a C ring or the like, and coils
76
p
and
76
y
(shifting coils) are forcibly pressed in the support frame
75
(
FIG. 43
shows a non-adhesive state). Light-projecting elements
77
p
and
77
y
such as IREDs are also adhered to the back face of the support frame
75
, and light emitted from the light-projecting elements is incident on position detecting elements
78
p
and
78
y
, such as PSDs, to be described later, through slits
75
ap
and
75
ay
respectively.
Support balls
79
a
and
79
b
each having a round tip, made of POM (polyacetal resin) or the like, and a charge spring
710
are inserted into holes
75
b
(provided in three places) of the support frame
75
(also see
FIGS. 40
,
41
A and
41
B). The support ball
79
a
is heat-caulked and fixed to the support frame
75
(where the support ball
79
b
is slidable in a direction to project from the hole
75
b
against the spring force of the charge spring
710
).
FIG. 40
is a transverse sectional view of the blur correction apparatus after assembly. Referring to
FIG. 40
, the support ball
79
b
, the charge spring
710
previously charged, and the support ball
79
a
, are inserted into the hole
75
b
of the support frame
75
in this order (where the support balls
79
a
and
79
b
have the same shape). The surrounding edge
75
c
of the hole
75
b
is heat-caulked to prevent the support ball
79
a
from coming off.
FIG. 41A
is a sectional view of the hole
75
b
taken on a line perpendicular to
FIG. 40
, and
FIG. 41B
is a plan view as seen from the direction indicated by the arrow
79
c
in FIG.
41
A. Reference labels A to D in
FIG. 41A
denote respective depths of regions labeled by A to D in FIG.
41
B.
Since the rear ends of vane portions
79
aa
of the support ball
79
a
are received in the region with the depth surface A, and movement of the vane portions
79
aa
is restricted by the depth surface A, the support ball
79
a
is fixed to the support frame
75
by heat-caulking the surrounding edge
75
c.
On the other hand, since the tips of vane portions
79
ba
of the support ball
79
b
are received in the region with a depth surface B, the support ball
79
b
is prevented from passing through the hole
75
b
in a direction indicated by the arrow
79
c
due to the spring force of the charge spring
710
.
After the correction apparatus has been assembled, since the support ball
79
b
is received by the second yoke
72
in the manner shown in
FIG. 40
, the support ball
79
b
is prevented from getting out of the support frame
75
even when the surface B is not provided. However, the surface B as the region to prevent the support ball
79
b
from passing through the hole
75
b
is provided for ease of assembly.
Since drilling of the hole
75
b
does not need any complicated internal sliding die even when the support frame
75
is made up by molding, and simple split-half dies can be used for molding the support frame
75
, the shape of the hole
75
b
of the support frame
75
shown in
FIGS. 40
,
41
A and
41
B can be set with high dimensional accuracy.
Thus the support balls
79
a
and
79
b
can be made up as the same parts, so that parts costs can be reduced without any assembly error. This is effective in parts control.
A material such as fluorine base grease is applied to a bearing portion
75
d
of the support frame
75
. An L-type shaft
711
(made of non-magnetic stainless steel) is then inserted in the bearing portion
75
d
(see FIG.
39
), with the other end of the L-type shaft
711
being inserted into a bearing portion
71
d
formed on the base plate
71
(after applying grease as well). After that, the support balls
79
provided in three places are put together on the second yoke
72
, and the support frame
75
is mounted in the base plate
71
.
Next, positioning
Adams Russell
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Smith Arthur A
LandOfFree
Image blur prevention 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 prevention apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Image blur prevention apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3214009