Television – Camera – system and detail – Combined image signal generator and general image signal...
Reexamination Certificate
2000-01-27
2004-06-22
Garber, Wendy R. (Department: 2612)
Television
Camera, system and detail
Combined image signal generator and general image signal...
C348S335000, C359S701000, C396S085000
Reexamination Certificate
active
06753911
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a zoom lens barrel and a camera employing the zoom lens barrel, and more particularly, to a zoom lens barrel having therein a zooming region and an accommodating region and to a camera such as a digital camera and a video camera employing this zoom lens barrel.
As a zoom lens barrel, there has so far been a barrel which conducts a change of a focal length of a lens system and an accommodating action. For example,
FIG. 6
shows constitution for a change of a focal length and an accommodating action in a zoom lens barrel representing an example of a prior art. As shown in the diagram, cam member
151
is provided with cam grooves
152
and
153
. The cam groove
152
is engaged with pin
172
which is provided on lens supporting frame
171
having therein lens group
173
, and the cam groove
153
is engaged with pin
182
which is provided on lens supporting frame
181
having therein lens group
183
.
The pins
172
and
182
are engaged also with linear guide groove
161
, and when the cam member
151
is turned in the direction of arrow mark A, the lens supporting frames
171
and
181
are guided by the linear groove
161
representing a guide member to move in the direction of arrow mark B. The cam grooves
152
and
153
make zooming action to be conducted by the portions of position P
1
and position P
2
, and make accommodating action to be conducted by the portions of position P
2
and position P
3
(TOKKAIHEI No. 2-6914).
However, since each of the cam grooves
152
and
153
on the cam member
151
has a groove portion for zooming and a groove portion for accommodating, the cam grooves
152
and
153
are long in the direction which is in parallel with an optical axis. In particular, for those wherein an optical system such as CCD is required to have telecentric characteristics in an image pickup element, the position of a lens in the course of photographing is far from CCD in the direction which is in parallel with an optical axis in many cases. Therefore, an amount of movement for accommodating is large, and thereby, cam grooves
152
and
153
are long in the direction being in parallel with an optical axis, which is a problem. Further, in the high magnification zoom lens wherein a lens group moves in full measure in the direction being in parallel with an optical axis between the occasion of accommodating and that of photographing, in particular, cam grooves
152
and
153
are long in the direction being in parallel with an optical axis, and a total length in the case of accommodating is long, which is a problem.
To prevent an error of lens inclination to an optical axis of an optical system, it is usually preferable to arrange three cam grooves. However, when the cam grooves are long as stated above, a diameter of a cam member is increased and a rise angle of the cam groove is made to be steep, for providing three cam grooves without an interference, which causes a problem that load on the driving section is increased.
SUMMARY OF THE INVENTION
The invention has been achieved in view of the problems stated above, and one of objects of the invention is to provide a zoom lens barrel which can easily be applied to a camera excellent in portability, by making a zoom lens which causes a camera to be large in size to be accommodated easily in a camera main body. Another object of the invention is to provide a camera to which the barrel stated above is applied.
The objects mentioned above are attained by either one of the following structures.
(1) A camera having a zooming function wherein there are provided a plurality of lens groups, a fixed frame fixed to a main body of the camera, a cam member engaging with the fixed frame so that the cam member is moveable in the optical axis direction, and a plurality of lens group supporting frames each engaging with the cam member and supporting each of the plural lens groups so that the lens group supporting frames may move in the optical axis direction to move the lens groups in the optical axis direction.
Due to this structure, even in the case of a camera wherein an amount of movement of lens groups is large, such as a digital camera and a video camera, cam grooves provided on a cam member can be made short in the optical axis direction, and a camera can be made small in size, because not only lens group supporting frames but also the cam member and lens group supporting frames are protruded in the optical axis direction when protruding the zoom lens barrel from a camera main body.
(2) A zoom lens barrel wherein there are provided a plurality of lens groups, a plurality of lens group supporting frames each supporting each of the plural lens groups, a guide member which guides plural lens group supporting frames in the direction being in parallel with an optical axis, a cam member which moves plural lens group supporting frames in the direction being in parallel with an optical axis by the movement of the lens group in the direction being in parallel with an optical axis, and moves at least two lens supporting frames among plural lens group supporting frames by the rotation of the lens group around an optical axis, a fixed frame which is composed of a first guide portion which guides the cam member in the direction being in parallel with the optical axis and of a second guide portion which guides the cam member in the direction to rotate around the optical axis, and a driving member which drives the cam member.
(3) The zoom lens barrel described in the above item (2) wherein the first guide portion and the second guide portion both formed on the fixed frame mentioned above are continuous cam grooves engaging respectively with the cam member,
(4) The zoom lens barrel described in the above item (3) wherein the first guide portion is a cam groove formed continuously in the direction for moving the cam member in the optical axis direction, and the second guide portion is a cam groove formed continuously in the direction for rotating the cam member without moving it substantially in the direction being in parallel with an optical axis.
(5) The zoom lens barrel described in the above item (4) wherein the cam groove of the first guide portion is a cam groove formed continuously in the direction which is mostly in parallel with an optical axis, and the cam groove of the second guide portion is a cam groove
(6) The zoom lens barrel described in Item (3) wherein the first guide portion is a cam groove formed continuously in the direction for moving the cam member in the direction parallel to the optical axis direction and for rotating, and the second guide portion is a cam groove formed continuously in the direction for rotating the cam member without moving it substantially in the direction being in parallel with an optical axis.
(7) The zoom lens barrel described in Item (6) wherein a cam groove of the first guide portion is one formed continuously in the direction inclined to the optical axis, and a cam groove of the second guide portion is one formed continuously in the prescribed direction in the plane which is mostly perpendicular to the optical axis.
(8) The zoom lens barrel described in either one of Item (2)-Item (7) wherein the driving member is a rotating ring having a cam groove which engages with the cam member for transmitting driving force to the cam member.
(9) The zoom lens barrel described in Item (8) wherein a cam groove of the rotating ring is one which is formed continuously in the direction inclined to the optical axis for moving the cam member in the optical axis direction and for rotating it.
(10) The zoom lens barrel described in Item (8) wherein a cam groove of the rotating ring is one wherein a portion formed continuously in the direction inclined to an optical axis for the purpose of moving the cam member in the optical axis direction and a portion formed continuously in the optical axis direction for the purpose of rotating the cam member without moving it substantially in the optical axis direction are connected.
(11) The zoom lens barrel des
Shimazaki Yoshio
Takahashi Yoshiharu
Yamada Tomokazu
Cantor & Colburn LLP
Garber Wendy R.
Konica Corporation
Villecco John
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