U.S. patent application number 11/216472 was filed with the patent office on 2006-03-02 for retractable lens camera.
This patent application is currently assigned to NIKON CORPORATION. Invention is credited to Minoru Kato.
Application Number | 20060045517 11/216472 |
Document ID | / |
Family ID | 35432172 |
Filed Date | 2006-03-02 |
United States Patent
Application |
20060045517 |
Kind Code |
A1 |
Kato; Minoru |
March 2, 2006 |
Retractable lens camera
Abstract
A retractable lens camera includes: a lens barrel; three or more
lens groups provided in the lens barrel; a retracting unit that
retracts the lens barrel and the lens groups into a camera body;
and a displacing unit that displaces at least two lens groups to an
escaping space out of an optical axis.
Inventors: |
Kato; Minoru;
(Utsunomiya-shi, JP) |
Correspondence
Address: |
STAAS & HALSEY LLP
SUITE 700
1201 NEW YORK AVENUE, N.W.
WASHINGTON
DC
20005
US
|
Assignee: |
NIKON CORPORATION
Tokyo
JP
|
Family ID: |
35432172 |
Appl. No.: |
11/216472 |
Filed: |
September 1, 2005 |
Current U.S.
Class: |
396/349 |
Current CPC
Class: |
G03B 17/04 20130101 |
Class at
Publication: |
396/349 |
International
Class: |
G03B 17/04 20060101
G03B017/04 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 2, 2004 |
JP |
JP 2004-255696 |
Claims
1. A retractable lens camera, comprising: a lens barrel; three or
more lens groups provided in the lens barrel; a retracting unit
that retracts the lens barrel and the lens groups into a camera
body; and a displacing unit that displaces at least two lens groups
to an escaping space out of an optical axis.
2. A retractable lens camera according to claim 1, wherein the
displacing unit displaces the at least two lens groups to the
escaping space in an identical direction.
3. A retractable lens camera according to claim 1, wherein, the
retracting unit moves the at least two lens groups in the escaping
space toward a rear of the camera.
4. A retractable lens camera according to claim 1, wherein the
escaping space is formed by disposing a photographing optical
system, which includes the three or more lens groups, with an
eccentric design in the lens barrel.
5. A retractable lens camera according to claim 1, wherein the at
least two lens groups are disposed in a direction of an optical
axis within the escaping space.
6. A retractable lens camera according to claim 1, wherein the lens
barrel comprises a turn cylinder; and the retracting unit retracts
the lens barrel and the lens groups into the camera body in
association with turning of the turn cylinder.
7. A retractable lens camera according to claim 6, wherein the
retracting unit includes: a holding member provided to a shaft
relatively stationary as to turning of the turn cylinder so as to
be swung around the shaft, with an end thereof across the shaft
holding a lens group of the at least two lens groups, and with the
other end having a protrusion; and a guide groove which is formed
on an inner face of the turn cylinder for engagement with the
protrusion, and which allows the protrusion to move by turning of
the turn cylinder, thereby displacing the lens group held by the
holding member from the optical axis to the escaping space.
8. A retractable lens camera according to claim 1, wherein the at
least two lens groups includes a zoom lens group and a focus lens
group.
9. A retractable lens camera according to claim 8, wherein: the
focus lens group includes a rack which contacts and is engaged with
a focus driving lead screw; and the displacing unit swings the
focus lens group to release the rack from being engaged with the
focus driving lead screw and displace the focus lens group to the
escaping space.
Description
INCORPORATION BY REFERENCE
[0001] The disclosures of the following priority application are
herein incorporated by reference:
[0002] Japanese Patent Application No. 2004-255696 filed Sep. 2,
2005
BACKGROUND OF THE INVENTION
[0003] 1. Field of the Invention
[0004] The present invention relates to a retractable lens
camera.
[0005] 2. Description of Related Art
[0006] With lens-non-detachable cameras, various types of
retractable lens cameras are known which have a function of
retracting a lens barrel within the camera body thereof, thereby
reducing the size thereof in the non-photographing state (see
Japanese Laid-open Patent Publication No. H9-203842).
SUMMARY OF THE INVENTION
[0007] The aforementioned cameras have a configuration which allows
the lens groups to move within the lens barrel along the optical
axis, thereby retracting the lens barrel within the camera body.
Such a camera has a limitation in which the thickness thereof
cannot be smaller than the sum of the total thickness of the lenses
and the clearances in the lens-barrel retracted state.
[0008] According to the 1st aspect of the invention, a retractable
lens camera comprises: a lens barrel; three or more lens groups
provided in the lens barrel; a retracting unit that retracts the
lens barrel and the lens groups into a camera body; and a
displacing unit that displaces at least two lens groups to an
escaping space out of an optical axis.
[0009] According to the 2nd aspect of the invention, in the
retractable lens camera according to the 1st aspect, it is
preferred that the displacing unit displaces the at least two lens
groups to the escaping space in an identical direction.
[0010] According to the 3rd aspect of the invention, in the
retractable lens camera according to the 1st or 2nd aspect, it is
preferred that the retracting unit moves the at least two lens
groups in the escaping space toward a rear of the camera.
[0011] According to the 4th aspect of the invention, in the
retractable lens camera according to any one of the 1st through 3rd
aspects, it is preferred that the escaping space is formed by
disposing a photographing optical system, which includes the three
or more lens groups, with an eccentric design in the lens
barrel.
[0012] According to the 5th aspect of the invention, in the
retractable lens camera according to any one of the 1st through 4th
aspects, it is preferred that the at least two lens groups are
disposed in a direction of an optical axis within the escaping
space.
[0013] According to the 6th aspect of the invention, in the
retractable lens camera according to any one of the 1st through 5th
aspects, it is preferred that the lens barrel comprises a turn
cylinder; and the retracting unit retracts the lens barrel and the
lens groups into the camera body in association with turning of the
turn cylinder.
[0014] According to the 7th aspect of the invention, in the
retractable lens camera according to the 6th aspect, it is
preferred that the retracting unit includes: a holding member
provided to a shaft relatively stationary as to turning of the turn
cylinder so as to be swung around the shaft, with an end thereof
across the shaft holding a lens group of the at least two lens
groups, and with the other end having a protrusion; and a guide
groove which is formed on an inner face of the turn cylinder for
engagement with the protrusion, and which allows the protrusion to
move by turning of the turn cylinder, thereby displacing the lens
group held by the holding member from the optical axis to the
escaping space.
[0015] According to the 8th aspect of the invention, in the
retractable lens camera according to any one of the 1st through 7th
aspects, it is preferred that the at least two lens groups includes
a zoom lens group and a focus lens group.
[0016] According to the 9th aspect of the invention, in the
retractable lens camera according to the 8th aspect, it is
preferred that: the focus lens group includes a rack which contacts
and is engaged with a focus driving lead screw; and the displacing
unit swings the focus lens group to release the rack from being
engaged with the focus driving lead screw and displace the focus
lens group to the escaping space.
[0017] The retracting unit and the displacing unit can replaced
with retracting means and displacing means respectively.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 is a cross-sectional diagram for describing a
retractable lens camera in the wide-angle state according to the
present invention.
[0019] FIG. 2 is a cross-sectional diagram which shows the camera
in the telephoto state.
[0020] FIG. 3 is a cross-sectional diagram which shows the camera
in the lens-barrel retracted state.
[0021] FIG. 4 is a diagram which shows a second-group lens system
as viewed from the direction A shown in FIG. 2.
[0022] FIG. 5 is a development which shows cam grooves 221 and 223
formed on the inner face of a cam cylinder 22.
[0023] FIGS. 6A and 6B are diagrams showing the actions of a
follower pin 271, where FIG. 6A is a cross-sectional diagram
showing the follower pin 271 within the cam groove 221, and FIG. 6B
is a cross-sectional diagram showing the follower pin 271 with the
tip thereof moving into the cam groove 223.
[0024] FIG. 7 is a cross-sectional diagram which shows the camera
after the turn R2 of the cam cylinder 22.
[0025] FIG. 8 is a diagram which shows a fourth-group lens system
as viewed from the direction B shown in FIG. 2.
[0026] FIGS. 9A through 9C are diagrams which show the relation
between a cam 235 and a holding frame 32, where FIG. 9A shows the
photographing state, FIG. 9B shows the state in which the holding
frame 32 is swung, and FIG. 9C shows the state in which the holding
frame 32 is moved toward the base.
[0027] FIG. 10 is a diagram which shows the whole retractable lens
camera including the lens barrel 2.
DESCRIPTION OF PREFERRED EMBODIMENT(S)
[0028] Description will be made below regarding the embodiment of
the present invention with reference to the drawings. FIGS. 1
through 3 are diagrams for describing a retractable lens camera
according to the present invention, and specifically, are
cross-sectional diagrams of an imaging system 1 and a lens barrel 2
of a digital still camera. Note that the lens barrel 2 mounted on
the camera according to the present embodiment is a zoom lens
barrel. FIG. 1 shows the camera in the wide-angle state, FIG. 2
shows the camera in the telephoto state, and FIG. 3 shows the
camera in the lens-barrel retracted state. FIG. 10 is a diagram
which shows the whole retractable lens camera including the lens
barrel 2. The lens barrel 2 is retracted into the camera body 100
and does not protrude from the camera body 100, at
non-photographing state.
[0029] In FIG. 1, reference numeral 3 denotes a base included in
the main body of the camera. The imaging system 1 and the lens
barrel 2 are fixed on the base 3. An imaging device 11 of the
imaging system 1 is fixed on the base 3. Furthermore, an optical
low-pass filter 12 is disposed upstream of the imaging device 11 on
the optical axis thereof at a predetermined interval therebetween.
Note that employed as the imaging device 11 is a CCD imaging device
or the like.
[0030] The lens barrel 2 includes a fixed cylinder 21 fixed to the
base 3, a cam cylinder 22, a linear-action cylinder 23, and a
first-group cylinder 24, each of which is mounted so as to allow
movement thereof as to the fixed cylinder 21 along the optical
axis. The fixed cylinder 21 is fixed on the base 3 with unshown
screws. A helicoidal internal thread 210 is formed on the inner
face of the fixed cylinder 21 for being screwed to a helicoidal
external thread 220 formed on the outer face of the cam cylinder
22. Upon turning the cam cylinder 22 as to the fixed cylinder 21 by
actions of an unshown motor, the cam cylinder 22 is moved along the
optical axis within the fixed cylinder 21.
[0031] The linear-action cylinder 23 is mounted so as to be
inserted into the cam cylinder 22, and is turnably connected to the
cam cylinder 22 at the rear end 230 thereof. Note that an unshown
protrusion is formed at the rear end 230 of the linear-action
cylinder 23 to protrude along the diameter direction. The
protrusion is engaged with a straight groove (not shown) formed on
the inner face of the fixed cylinder 21. This engagement allows the
action of the liner-action cylinder 23 as follows. That is to say,
upon turning the cam cylinder 22, the linear-action cylinder 23 is
moved straight along with the cam cylinder 22 integrally along the
optical axis without rotation of the linear-action cylinder 23.
[0032] The linear-action cylinder 23 includes second-group lenses
25 and third-group lenses 26 therewithin. The third-group lenses 26
are held by a holding frame 28 fixed to the linear-action cylinder
23, which allows the third-group lenses to integrally move along
with the linear-action cylinder 23 along the optical axis.
Furthermore, a shutter unit 29 is fixed to the holding frame 28. A
holding frame 27 for holding the second-group lenses 25 is mounted
to a guide shaft 231 provided to the linear-action cylinder 23 so
as to allow sliding thereof along the optical direction.
Furthermore, the holding frame 27 is mounted so as to allow
swinging motion thereof with the guide shaft 231 as an axis.
[0033] A torsion compression spring 232 provided to the guide shaft
231 presses the holding frame 27 in the forward direction of the
camera (in the left direction in the drawing) by compression force.
At the same time, the torsion force of the torsion compression
spring 232 presses an engaging portion 270 formed on the holding
frame 27 to contact with a guide shaft 233. Furthermore, a follower
pin 271 is formed on the outer face of the holding frame 27. The
tip of the follower pin 271 is engaged with a cam groove 221 formed
on the inner face of the cam cylinder 22. With such a
configuration, upon turning the cam cylinder 22, the holding frame
27 is moved along the optical axis within the cam cylinder 22.
[0034] The first-group cylinder 24 holding the first-group lenses
30 is mounted so as to be inserted into the cam cylinder 22.
Furthermore, a follower pin 240 formed on the outer face of the
first-group cylinder 24 is engaged with a cam groove 222 formed on
the inner face of the cam cylinder 22. Furthermore, a protrusion
241 formed on the inner face of the first-group cylinder 24 is
engaged with a guide groove 234 formed on the linear-action
cylinder 23. With such a configuration, upon turning the cam
cylinder 22, the first-group cylinder 24 is moved within the cam
cylinder 22 along the optical axis. Reference numeral 31 denotes a
fourth-group lens held by a holding frame 32. The holding frame 32
is slidably mounted to a guide shaft 33 provided on the base 3.
Furthermore, the holding frame 32 is mounted so as to allow
swinging motion thereof with the guide shaft 33 as an axis.
[0035] A torsion compression spring 330 provided to the guide shaft
33 presses the holding frame 32 in the forward direction of the
camera (in the left direction in the drawing) by compression force.
At the same time, the torsion force thereof presses a rack 320
formed on the holding frame 32 to contact with a lead screw 321.
FIG. 1 shows the camera in the wide-angle state, and FIG. 2 shows
the camera in the telephoto state. In either state, the lead screw
321 mounted to the rotation axis of a motor 322 is screwed to the
rack 320 formed on the holding frame 32. With such a configuration,
upon rotation of the motor 322, the holding frame 32 holding the
fourth-group lens 31 is moved along the optical axis. The movement
of the fourth-lens 31 allows focus adjustment.
[0036] At the time of switching from the wide-angle state shown in
FIG. 1 to the telephoto state shown in FIG. 2, the cam cylinder 22
is turned so as to extend forward. In this case, the linear-action
cylinder 23 and the cam cylinder 22 are moved forward integrally.
Furthermore, the first-group cylinder 24 is moved along the optical
axis following the guide of the cam groove-222. On the other hand,
the holding frame 27 holding the second-group lenses 25 is moved
along the optical axis following the guide of the cam groove 221.
As a result, the camera enters the telephoto state as shown in FIG.
2.
[0037] In any photographing state between the wide-angle state
shown in FIG. 1 and the telephoto state shown in FIG. 2, the
first-group lenses 30, the second-group lenses 25, the third-group
lenses 26, and the fourth-group lens 31, are disposed in a straight
line on the optical axis J. Let us say that the camera enters the
lens-barrel retracted state shown in FIG. 3 from the wide-angle
state shown in FIG. 1. In this case, the second-group lenses 25 and
the fourth-group lens 31 are displaced from the position on the
optical axis J to an escaping space S within the linear-action
cylinder 23, shown at the upper portion in the drawing. At the same
time, the cam cylinder 22, the linear-action cylinder 23, and the
first-group cylinder 24, are moved backward. Thus, the lens barrel
formed of such cylinders is retracted within the fixed cylinder
21.
[0038] Next, description will be made regarding the configuration
of the second-group lens system, the configuration of the
fourth-group lens system, and the displacing action.
[Regarding the Actions of the Second-Group Lens System]
[0039] FIG. 4 is a diagram which shows the second-group lens system
as viewed from the direction A shown in. FIG. 2. The linear-action
cylinder 23 is mounted so as to be inserted into the cam cylinder
22. As described above, the holding frame 27 holding the
second-group lenses 25 is mounted so as to allow the swinging
motion thereof with the guide shaft 231 as an axis. Note that the
torsion compression spring 232 presses the engaging portion 270 to
contact with the guide shaft 233.
[0040] In the drawing, represented by the solid line is the holding
frame 27 positioned in the photographing state as shown in either
FIG. 1 or FIG. 2. In this case, the second-group lenses 25 are
disposed on the optical axis J. On the other hand, represented by
the alternate long and two short dashes line is the holding frame
27 positioned in the lens-barrel retracted state shown in FIG. 3.
As shown in FIG. 4, the optical axis J of the photographic optical
system is shifted downward in the drawing by the distance d from
the center axis J2 of the cam cylinder 22 and the linear-action
cylinder 23. Accordingly, regarding the space in the linear-action
cylinder 23, the space above the optical axis J is larger than the
space below. Such an eccentric design of the optical axis J allows
formation of the escaping space S above the shutter unit 29 as
shown in FIG. 3.
[0041] In the wide-angle state shown in FIG. 4, the follower pin
271 provided to the holding frame 27 is engaged with the cam groove
221. Note that the cam groove 221 used for zoom actions in the
photographing state communicates with a lens-barrel retracting
groove 223. Upon turning the cam cylinder 22 in the direction of
the arrow R in the wide-angle state shown in FIG. 4, the follower
pin 271 is moved out from the cam groove 271 to the cam groove 223,
thereby swinging the holding frame 27 holding the second-group
lenses 25. Thus, the holding frame 27 is displaced upward from the
optical axis J as represented by the alternate long and two short
dashes line.
[0042] FIG. 5 is a diagram for describing the cam grooves formed on
the inner face of the cam cylinder 22, and specifically, is a
development which shows the cam groove 221 used for the wide-angle
state around the end thereof, and the cam groove 223 used for the
lens-barrel retracting actions. On the other hand, FIGS. 6A and 6B
show the actions of the follower pin 271 following the guide of the
cam grooves 221 and 223. With the present embodiment, the cam
grooves 221 and 223 communicate with each other. Furthermore, the
cam groove 223 is formed with a smaller depth than that of the cam
groove 221 as shown in FIG. 6A.
[0043] Upon turning the cam cylinder 22 as represented by the
arrows R1, R2, and R3, in that order, as shown in FIG. 5, the cam
grooves 221 and 223 are moved in order, as to the follower pin 271
of the holding frame 27, as represented by the alternate long and
two short dashes lines. First, upon application of the turn R1 to
cam cylinder 22, the follower pin 271 is moved from a zoom position
to a wide-angle end on the cam groove 221. At the same time, the
holding frame 27 is moved toward the base by a predetermined
distance denoted by the arrow E. Furthermore, the first-group
cylinder 24 shown in FIG. 1 is moved toward the base 3 due to the
turn of the cam cylinder 22. Upon the follower pin 271 reaching the
wide-angle end of the cam groove 221, the end 242 of the
first-group cylinder 24 comes in contact with the follower pin 271.
In this state, the follower pin 271 positioned at the wide-angle
end of the cam groove 221 is orthogonally engaged with the cam
groove 221 as shown in FIG. 6A.
[0044] Upon further turning the cam cylinder 22 after the turn R1,
the follower pin 271 tilts within the cam groove 221 as shown in
FIG. 6B, thereby swinging the holding frame 27 with the guide shaft
231 as an axis. Then, upon turning the cam cylinder 22 by the turn
R2, the follower pin 271 tilts so that the tip thereof is
positioned at the same height as that of the bottom of the cam
groove 223. Note that the swinging angle of the holding frame 27 is
determined by the difference in the depth between the cam grooves
221 and 223. On the other hand, the first-group cylinder 24 is not
moved along the optical axis during the turn R2 of the cam cylinder
22, thereby keeping the end 242 of the first-group cylinder 24 and
the follower pin 271 in contact with each other.
[0045] FIG. 7 is a cross-sectional diagram which shows the camera
after the turn R2. In this state, the second-group lenses 25 are
displaced from the optical axis J to the escaping space S above the
three-group lenses 26 due to the swinging of the holding frame 27.
Then, upon further turning the cam cylinder 22 by the turn R3, the
first-group cylinder 24 is moved toward the base 3, and the end 242
presses the follower pin 271 toward the base. As a result, as shown
in FIG. 6B, the follower pin 271 slides out from the cam groove
221, and moves toward the base 3 following the guide of the cam
groove 223 as shown in FIG. 5.
[0046] As a result, as shown in FIG. 7, the first-group cylinder 24
and the second-group lenses 25 move integrally toward the base 3.
Furthermore, the second-lenses 25 are moved above the third-group
lenses 26. With the present embodiment described above, following
the follower pin 271 sliding out from the cam groove 221, the end
242 of the first-group cylinder 24 presses the follower pin 271
toward the base 3, thereby moving the holding frame 27 backward
toward the base 3. With such a mechanism, the present invention is
not restricted to a configuration including the cam groove 223,
rather, an arrangement may be made which allows the follower pin
271 to slide out from the cam groove 221 to the inner face of the
cam cylinder 22 having no cam groove 223.
[0047] With such a configuration as well, the follower pin 271 is
pressed into contact with the inner face of the cam cylinder 22 by
actions of the torsion compression spring 232, thereby preventing
the holding frame 27 from turning as to the linear-action cylinder
23. Accordingly, such a configuration allows the same path of the
follower pin 271 as that shown in FIG. 5.
[Regarding the Actions of the Fourth-Group Lens System]
[0048] FIG. 8 is a diagram which shows the fourth-group lens system
as viewed from the direction B shown in FIG. 2. As described above,
the fixed cylinder 21, the cam cylinder 22, and the linear-action
cylinder 23, are disposed in that order from the outside. The
holding frame 32 holding the fourth-group lens 31 is slidably
mounted to the guide shaft 33 fixed to the base 3 (see FIG. 1).
Note that the linear-action cylinder 23 is represented by the
alternate long and two short dashes line in the drawing. The
torsion compression spring 330 applies torsion to the holding frame
32 such that the holding frame 32 is turned counterclockwise. The
rack 320 of the holding frame 32 is pressed to contact with and be
screwed to the lead screw 321.
[0049] FIG. 8 shows the camera in the telephoto state in which the
fourth-group lens 31 is disposed on the optical axis J. Reference
numeral 235 denotes a cam provided to the linear-action cylinder
23. Upon the cam 235 engaging with the holding frame 32 holding the
fourth-group lens 31, the holding frame 32 is swung. In the
drawing, represented by the alternate long and two short dashes
line is the holding frame 32 turned clockwise and displaced from
the optical axis J by actions of the cam 235.
[0050] FIGS. 9A through 9C are diagrams which show the relation
between the cam 235 and the holding frame 32, and is a diagram
which shows a part of the cam 235 as viewed from the side of the
guide shaft 33 shown in FIG. 8. FIG. 9A shows the state in which
the cam 235 and the holding frame 32 are not engaged with each
other. Note that the cam 235 and the holding frame 32 are disposed
in the state as shown in FIG. 9A in any state between the telephoto
state and the wide-angle state. On the other hand, FIGS. 9B and 9C
show the state in which the cam 235 and the holding frame 32 are
engaged with each other. In other words, FIGS. 9B and 9C show the
cam 235 and the holding frame 32 in the lens-barrel retracted
state.
[0051] With such a configuration, the cam 235 and the linear-action
cylinder 23 are moved integrally. Note that a slope 235a and a
pressing face 235b are formed at the tip of the cam 235. In the
state shown in FIG. 9A, the rack 320 of the holding frame 32 is
pressed to contact with and be screwed to the lead screw 321, and
the fourth-group lens 31 is disposed on the optical axis J. Upon
further turning the cam cylinder 22 in the wide-angle state shown
in FIG. 1, the lens-barrel retracting action is executed. In the
lens-barrel retracting action, the cam 235 is moved backward toward
the base 3, and the slope 235a comes in contact with the holding
frame 32.
[0052] Then, upon the cam 235 further moving backward as shown in
FIG. 9B, the holding frame 32 is moved upward against the torsion
force of the torsion compression spring 330. While the force
applied to the holding frame 32 from the slope 235a has a backward
component, the compression force of the torsion compression spring
330 is designed so as to be greater than the backward component.
Accordingly, the holding frame 32 is turned-without sliding
backward. As a result, the rack 320 of the holding frame 32
disengages from the lead screw 321, and the fourth-group lens 31
starts to move away from the optical axis.
[0053] Upon cam 235 further moving backward, the holding frame 32
is moved upward to the position of the pressing face 235b. In this
state, the camera completely enters the lens-barrel retracted state
as shown in FIG. 8, in which the fourth-group lens 31 is swung from
the optical axis J to the escaping space above the optical axis J.
The fourth-group lens 31 is displaced to the space within the
linear-action cylinder 24, formed above the optical axis J shifted
from the center of the linear-action cylinder 24 in the same way as
with the second-group lenses 25. With the present embodiment, the
second-group lenses 25 and the fourth-group lens 31 thus displaced
are disposed in a line in the thickness direction as shown in FIG.
3. Subsequently, the holding frame 32 is pushed toward the base 3
against the compression force of the torsion compression spring 330
while maintaining the state in which the holding frame 32 and the
pressing face 235b are pressed to contact with each other. Thus,
the camera enters the lens-barrel retracted state shown in FIG.
3.
[0054] In the embodiment, the second-group lenses 25 and the
fourth-group lens 31 are displaced or moved out in the same
direction perpendicular to the optical axis of the lens barrel 2,
and displaced or moved out into the same escaping space. By this
means, the size of the lens barrel and the size of the retractable
lens camera in the diameter direction of lens are reduced.
[0055] With the present embodiment as described above, the optical
axis J of the photographing optical system is designed to be
positioned downward from the center axis J2 of the lens barrel 2 so
as to form the escaping space S above the optical axis J as shown
in FIG. 3. Such a configuration allows the second-group lenses 25
and the fourth-group lens 31 to be completely displaced to the
escaping space. Note that in the retracted state, the second-group
lenses 25 and the fourth-group lens 31 do not overlap with the
first-group lenses 30 and the third-group lenses 26 in the
thickness direction.
[0056] However, the present invention is not restricted to such an
arrangement, rather, an arrangement may be made in which the
second-group lenses 25 and the fourth-group lens 31 are swung
somewhat less such that the second-group lenses 25 and the
fourth-group lens 31, thus displaced, overlap with the first-group
lenses 30 and the third-group lenses 26 in the lens-barrel
retracted state. Even with such a configuration, the camera has the
advantage of reducing the thickness thereof in the lens-barrel
retracted state since the lens group is somewhat shifted from the
optical axis. Furthermore, an arrangement may be made in which the
lens-barrel center axis J2 matches the optical axis J, and the
swinging of the second-group lenses 25 and the fourth-group lens 31
is designed according to such a layout.
[0057] With the present embodiment described above, the
second-group lenses 25 and the fourth-group lens 31 are turned in
the same direction so as to be disposed in a line in the thickness
direction. Also, an arrangement may be made in which the
second-group lenses 25 and the fourth-group lens 31 are turned in
opposite directions with the optical axis J as the center. With
such a configuration, the second-group lenses 25 and the
fourth-group lens 31 are not disposed serially in the thickness
direction, but can be disposed opposite one to another across the
optical axis at generally the same position in the optical-axis
direction, in the lens-barrel retracted state. Such a configuration
allows more reduction of the overall thickness of the camera in the
lens-barrel retracted state. While description has been made
regarding an arrangement in which two of the four lens groups are
displaced away from the optical axis, an arrangement may be made in
which three of the four lens groups are displaced away.
Furthermore, the present invention is not restricted to an
arrangement including the four lens groups, rather, the present
invention may be applied to an arrangement including three, five,
or more lens groups.
[0058] The above described embodiments are examples, and various
modifications can be made without departing from the spirit and
scope of the invention.
* * * * *