A lens barrel of the present invention includes a fixed frame, a plurality of lens groups disposed on the inner circumference of the fixed frame movably along an optical axis direction with respect to the fixed frame, at least three lens holding frames for holding at least one lens group of a plurality of the lens groups, a cam frame having bottomed cam grooves to be coupled with the inner circumference of the fixed frame through cams, bottomed cam grooves across each other to be coupled with the lens holding frames through cams and a bottomed cam groove which is discontinued on one end surface and continued from the other end surface.
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8. A lens barrel comprising:
a cam frame with cam grooves respectively provided on an inner periphery and an outer periphery thereof; and at least first and second frame members each having cam followers which engage with said cam grooves respectively provided within the inner periphery and about the outer periphery of said cam frame; wherein a depth of a cam groove provided the inner periphery of said cam frame and a depth of a cam groove provided on the outer periphery of said cam frame is set to be smaller than a thickness of said cam frame measured in a radial direction, at least one of said cam grooves being non-linear.
7. A lens barrel, comprising:
a fixed first frame; a plurality of lens holding frames movable along an optical axis direction with respect to said fixed first frame; a cam frame for moving a plurality of lens groups along the optical axis direction with respect to said fixed first frame responsive to rotation about said optical axis with respect to said fixed first frame; and a plurality of bottomed cam grooves provided with said cam frame with which cam followers provided with said lens holding frames are engaged and at least one of a plurality of said bottomed cam grooves is a non-linear cam groove and is divided at at least one position of a front end surface or rear end surface of said cam frame.
1. A lens barrel, comprising:
a fixed first frame; a plurality of lens groups disposed on an inner circumference of said fixed first frame and movable along an optical axis direction with respect to said fixed first frame; lens holding frames for holding at least one of said lens groups; and a cam frame for moving said lens holding frames in an optical axis direction responsive to rotation about an optical axis with respect to said fixed first frame, said cam frame having a plurality of bottomed cam grooves engaged by cam followers provided on said lens holding frames, at least two of a plurality of said bottomed cam grooves cross each other at at least one position of an inner circumference or other circumference of said cam frame.
6. A lens barrel, comprising:
a fixed first frame; a plurality of lens groups disposed on an inner circumference of said fixed first frame and movable along an optical axis direction with respect to said fixed first frame; lens holding frames for holding at least one of said lens groups; a cam frame coupled with the inner circumference of said fixed first frame through cams and moving along the optical axis direction with respect to said fixed first frame responsive to rotation about said optical axis with respect to said fixed first frame; a plurality of bottomed cam grooves provided with said cam frame with which cam followers provided with said lens holding frames are engaged and at least one of a plurality of said bottomed cam grooves is a non-linear cam groove and is divided at at least one position of a front end surface or rear end surface of said cam frame.
2. A lens barrel according to
3. A lens barrel according to
4. A lens barrel according to
5. A lens barrel according to
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This is a division of application Ser. No. 08/359,415, filed Dec. 20, 1994, now U.S. Pat. No. 5,818,647.
1. Field of the Invention
The present invention relates to a lens barrel, and more specifically to a lens barrel having a plurality of lens groups disposed therein so that they can extend and retract in an optical axis direction.
2. Related Art Statement
Conventionally, there are proposed various lens barrels for effecting zooming by moving frames for holding lens groups in an optical axis direction by the rotation of a cam frame accommodated inside a fixed frame.
As an example of such lens barrels, Japanese Patent Application Laid-open No. 53-102030 discloses a lens barrel provided with two fixed frames, wherein a first lens group is rotated and slid and a cam frame is driven by the rotation
Embodiments of the present invention will be described below with reference to the drawings.
First, the concept of a lens barrel in an embodiment of the present invention will be described with reference to examples shown in FIG. 3 and FIG. 4.
The lens barrel accommodates, for example, three lens holding frames 400b, 400c, 400d which are sequentially disposed in this order from the distal side to the proximal side of an optical axis on the inside diameter side of a fixed frame 400a. Of these lens holding frames, a rod member 400e is extended from the lens holding frame 400b disposed on the distal side of the optical axis to the proximal side thereof as well as a rod member 400h is extended from the lens holding frame 400d disposed on the proximal side of the optical axis to the distal side thereof and the lens holding frame 400c can be moved in an optical axis direction by being supported in such an arrangement that the rod members 400e, 400h are inserted into a bearing 400f.
Note, the above rod members 400e, 400h are disposed at the positions substantially equally divided in a circumferential direction (i.e. they lie on a common diameter).
As shown in
The camera of the embodiment includes as its main components the camera body 74, a front panel 74 fixed on the front surface of the camera body 74 by screws 76 threaded from rear side of the camera body and having a mirror 75a and a finder 75b, a lens plate 46 fixed to the camera body 74 at a position in front of the front plate 75 by screws 72 threadedly through the lens plate 46, the lens plate 46 having a lens unit 73 disposed on the front surface thereof and reinforcing the strength of the entire lens barrel, a rear cover 77 engaged with the camera body 74 from the rear side thereof so that is abutted against the camera body 74 through a projection 77a, and a front cover 78 engaged with the lens plate 46 from the front side thereof so that it is abutted against the lens plate 46b through a projection 78a.
The zoom lens barrel includes a first group frame 38 for holding a first group lens, a second group frame 1 for holding a second group lens, a third group frame 5 for holding a third group lens, a fourth group frame 13 for holding a fourth group lens and a fifth group frame 19 for holding a fifth group lens which are sequentially disposed in this order from the distal side (object side) of an optical axis along the axis.
A cam frame 24 is disposed on the outer circumferential side of the second group frame 1, the third group frame 5, the fourth group frame 13 and the fifth group frame 19, a first zoom frame 31 which is threadedly engaged with the first group frame 38 through a screw portion 39 is disposed around the cam frame 24 and further a fixed frame 34 is disposed around the first zoom frame 31 and fixedly mounted on the lens plate 46.
The second group frame 1 includes a circumferential-wall-shaped projected portion 1c projecting from the end face of the frame 1 on the proximal side of the optical axis (the camera body side) in the optical axis direction within a predetermined circumferential area. The projected portion 1c has a rotation stop key way 1b defined on the outer circumference thereof and a key way 1d defined on the inner circumference thereof each in parallel with the optical axis and a rod 2 extending in the optical axis direction. The second group frame 1 has three pins 3 which project from it integrally therewith to the outside and are located at the positions shown and are equally divided in the circumferential direction of the frame 1. Three projections 30 are formed with respect to the pins 3 at the positions substantially equally divided in a circumferential direction on the distal side of the optical axis (the object side). The second group frame 1 further has a key way 1a parallel with the optical axis (refer to FIG. 9).
The third group frame 5 has substantially cylindrical bearings 7, 8, 9 disposed at the positions substantially equally divided in a circumferential direction, respectively, each of the bearings having sleeves 6 at both ends thereof. The bearing 8 of these bearings has a projection 23 projecting on the proximal side in the axis direction (on the camera body side) and the projection 23 has a pin 12 projecting outwardly and integrally formed therewith. Further, the third group frame 5 has a guide projection 10 disposed at a position between the bearing 7 and the bearing 8 in a circumferential direction and extending to the proximal side in the optical axis direction and a guide projection 11 disposed at a position between the bearing 8 and the bearing 9 and extending to the proximal side in the optical axis direction.
The fourth group frame 13 has a pin 15 projecting from the circumference thereof outwardly and formed integrally therewith and a rotation stopping groove 16 defined to the circumference thereof. Further, a rod 14 directed to the distal side of the optical axis in parallel therewith is attached to the fourth group frame 13 and the groove 16 and the rod 14 are disposed at the positions substantially equally divided in a circumferential direction. In addition, the fourth group frame 13 has a stepping motor 17 for adjusting a diaphragm and a band-shaped substrate 18 is extended from the stepping motor 17.
The fifth group frame 19 has a pin 22 integrally formed therewith and extending outwardly and a rotation stop groove 20 defined thereto. Further, a rod 21 directed to the distal side of the optical axis in parallel therewith is attached to the outer circumference of the fifth group frame 19 and the groove 20 and the rod 21 are disposed at the positions substantially equally divided in a circumferential direction.
Note, when these rods 2, 14 and 21 are made to have the same diameter, respectively, the bearings corresponding to them can be also made to have the same diameter, by which a manufacturing cost can be reduced.
Th cam frame 24 is a cylindrical member having several bottomed cams 26 which constitute a cam mechanism and are defined on the inner circumference thereof and an internal gear 29 is partially formed on the inner circumference of the cam frame 24 at the end on the proximal side of the optical axis (on a photographer side) thereof. Further, several bottomed cams 25 constituting a cam mechanism are also defined on the outer circumference of the cam frame 24 as well as an encoder 28 which is mounted thereon and three pins 27 integrally project from the end on the proximal side of the optical axis of the cam frame 24.
The first zoom frame 31 has three linear traveling grooves 33 defined on the inner circumference thereof at the positions equally divided in a circumferential direction, respectively. Further, pins 50, 51, 52 integrally project from the inner circumference of the first zoom frame 31 as well as a substantially rectangular projection 49 extends from the proximal end on the inner circumference of the frame 31 and a pin 32 separate from the first zoom frame 31 is disposed upon the projection 49.
The fixed frame 34 is a cylindrical member having cams 112 on the inner circumference thereof and a ring 36 is engaged with the fixed frame 34 at the end thereof on the distal side in the optical axis direction and a substrate 35 having a photoreflector (PR) 48 is attached on the outer circumference of the fixed frame 34. Further, several bosses 37 are spaced about and project from the proximate end circumferential surface in the optical axis direction of the fixed frame 34 along a circumferential direction.
The lens plate 46 is composed of a sheet-shaped member having holes 47 defined at the four corners thereof and has a key 40 serving as a reinforcing member and a key 42 serving as a similar reinforcing member attached thereto in such a manner that they are vertical with respect to the front surface of the lens plate 46. A multiplicity of thin light shield grooves 41 are defined in the key 40 perpendicular to the optical axis and a pinion gear 43 extending in the optical axis direction is mounted on the key 42. Further, a zoom motor 45 as a drive source and a second gear box 44 having a gear train for transmitting a drive force from the zoom motor 45 are mounted on the lens plate 46. The final gear of the gear train is meshed with the pinion gear 43 mounted on the key 42.
Next, the alignment of the respective lens holding frames will be described below.
The third group frame 5 is movable in the optical axis direction with respect to the second group frame 1 by the arrangement that the rod 2 is inserted into the bearing 8 and further the position in the radial direction of the third group frame 5 is determined with respect to the second group frame 1 by the bearings 7, 9 which regulate the radial direction.
The fourth group frame 13 is movable in the axis direction with respect to the third group frame 5 by the arrangement that the rod 14 is inserted into the bearing 7 and further the position in the radial direction of the fourth group frame 13 is determined with respect to the third group frame 5 by the groove 16 engaged with the guide projection 11.
The fifth group frame 19 is movable in the axis direction with respect to the third group frame 5 by the arrangement that the rod 21 is inserted into the bearing 9 and further the position in the radial direction of the fifth group frame 19 is determined with respect to the third group frame 5 by the groove 20 engaged with the guide projection 10.
More specifically, the respective lens holding frames are aligned with each other in such a manner that the fourth group frame 13 and the fifth group 19 are positioned with respect to the third group frame 5 and the third group frame 5 is positioned with respect to the second group frame 1.
Further, the other frame members are aligned as described below.
The position in the radial direction of the cam frame 24 is determined in such a manner that the pins 3, 12, 15, 22 are engaged with the cam 26 on the inner circumference of the can frame 24.
Further, the position in the radial direction of the cam frame 24 is determined in such a manner that the pin 50 of the first zoom frame 31 is engaged with the cam 25 and the position in the radial direction of the second group frame 1 is determined in such a manner that the projections 30 at the three positions are engaged with the linearly traveling grooves 33 at the three positions of the first zoom frame 31, respectively with respect to the first zoom frame 31. The position of the first group frame 38 is determined in such a manner that the screw portion 39 is threadedly engaged with the extreme end of the first zoom frame 31.
The position in the radial direction of the cam frame 24 is determined with respect to the fixed frame 34 in such a manner that the three pins 27 are engaged with the cams 112 at the three positions of the fixed frame 34.
The position of the fixed frame 34 is determined by fitting the bosses 37 to the lens plate 46 and the rotation of the second group frame 1 about the optical axis is regulated by fitting the key 40 to the key way 1b of the second group frame 1.
Since the respective lens holding frames are supported as described above, the length of the lens barrel in its retracted state is substantially made equal to the sum of the lengths in the axial direction of the second group frame 1, the third group frame 5, the fourth group frame 13 and the fifth group frame 19, so that the length in the optical axis of the lens barrel can be remarkably shortened.
As described above, the keys 40, 42 extending to the distal side of the optical axis in parallel therewith are fixed on the front surface of th lens plate 46 through key mounting units 40a, 42a provided with the keys 40, 42.
A light shield groove is also defined on the inside of the key 42 similar to the key 40 and an arm 94 circumferentially extends from the key 42. The arm 94 has a pinion gear 43 with a long shaft disposed thereon, the pinion gear 43 is held between the arm 94 and the lens plate 46 and the lower portion of the pinion gear 43 has a different gear diameter.
Since there is a possibility that the pinion gear 43 may bend because it is a long shaft, it is made of metal to avoid the bending.
The key 40 and the key 42 are fitted to the key ways 1b, 1a defined on the second group frame 1, respectively to regulate the rotation of the second group frame 1. Further, since these keys 40, 42 are made of metal, they can also reinforce the lens unit 73.
The key 40 and the key 42 can be formed from, for example, an aluminium diecast product, zinc diecast or the like and the respective components of the frame members including the second group frame 1 and the like may be molded by a plastic material or the like which is lighter and less rigid, by which the key 40 and the key 42 substantially assure the rigidity of the entire lens unit 73 and serve as a reference when the respective components of the lens barrel are positioned.
Note, the rotation of the first zoom frame 31 about the optical axis is regulated in such a manner that the three linear traveling grooves 33 which are disposed on the inner circumference of the first zoom frame 31 and parallel with the optical axis direction are engaged with the three projections 30 disposed on the outer circumference of the second group frame 1 on the distal side of the optical axis.
Next, the arrangement of a zoom gear mounted on the lens plate 46 will be described with reference to FIG. 11.
The above key 40 for regulating the rotation of the second group frame 1 about the optical axis and the long shaft pinion gear 43 for rotating the cam frame 24 are mounted on the front surface (the lower surface in
The zoom motor 45 constitutes the first stage planetary gear mechanism in the first gear box 241 using a pinion gear mounted on the output shaft thereof as a sun gear.
A carrier on the final stage in the first gear box 241 is meshed with the eternal gear in the second gear box 44 and transmits a drive force through a gear 235 meshed with a gear 236 which has a disk 237 integrally disposed on the rear surface thereof and is rotated therewith, the disk having a plurality of slits defined therethrough in its circumference direction.
The gear 235 is integrally and coaxially provided with a gear 243 having a different diameter on the front surface thereof. In addition, there is provided an idle gear 244 which is meshed with the gear 243 and further meshed with a gear 242 mounted on the base end portion of the pinion gear 43 and having a different diameter.
Further, a C-shaped photointerrupter (PI) 239 is disposed and holds the disk 237 therebetween and a flexible substrate 238 is attached to the photointerrupter 239.
When the zoom motor 45 rotates, the planetary gear mechanisms in the first gear box 241 are driven and successively the gear train in the second gear box 44 is driven. Further, the gear 236 and the disk 237 are rotated through the gear 235.
When the slits of the disk 237 pass through the photointerrupter 239, light passes through the slits and signals flow to the flexible substrate 238. On the other hand, when the portion of the disk 237 without the slits passes therethrough light is interrupted and no signal flows to the flexible substrate 238. Therefore, when the disk 237 rotates, a pulse wave flows to the flexible substrate 238.
On the other hand, when the gear 243 is rotated by the rotation of the gear 235, the gear 242 is rotated through the gear 244 and the long shaft pinion gear 43 is driven in rotation accordingly.
As shown in
The rotation about the optical axis of the second group frame 1, the third group frame 5, the fourth group frame 13 and the fifth group frame 19 is regulated by the key 42, they move forward and backward along the cam 26 on the inner circumference of the cam frame 26 in on the axial direction without being rotated.
The photoreflector 48 of the substrate 35 attached to the fixed frame 34 is provided with a light emitting element and a light receiving element and light emitted from the light emitting element is reflected on the outer circumference of the cam frame 24 and incident on the light receiving element. Since the encoder 28 mounted on the cam frame 24 has a light reflectance ratio which is larger than that of the other portion of the circumference of the cam frame 24, when the encoder 28 passes through a position corresponding to the photoreflector 48, signals output from the photoreflector 48 are changed.
When the cam frame 24 rotates, W+1(a few pulses after the wide (WIDE) end) is supposed to be a time at which an end 28a of the encoder 28 passes through the photoreflector 48, T-1 (a few pulses before the telephone (TELE) end) is supposed to be time at which the other end 28b of the encoder 28 passes through the photoreflector 48 and the photointerrupter 239 is reset at these times.
When the lens barrel is zoomed from its retracted position to the wide end or the telephoto end or from a standard (STD) end to the wide end or the telephone end, the lens barrel is caused to surely pass through the reset position of the photointerrupter 239 and the dispersion of the pulses of the photointerrupter 239 resulting from backlash is eliminated. As a result, zooming can be carried out so that the cam frame 24 stops at an accurate position.
As shown in
The screw frame 142 has a screw portion 143 defined at the extreme end on the inner circumference thereof, an internal gear 144 defined in a predetermined range at the rear end of the inner circumference along its circumferential direction and a helicoid 145 defined at the rear end of the outer circumference thereof along its circumferential direction. Further, the screw frame 142 has two projections 146, 147 in the vicinity of the terminal end of the internal gear 144. One of the projections 147 projects in the inside diameter direction of the screw frame 142 and the other projection 146 projects toward the proximal side of the optical axis.
On the other hand, the lens drive unit 157 mounted on the inner circumference of the first zoom frame 31 includes a motor 153 as a drive source, a gear box 149 containing a gear train for reducing a drive force from the motor 153 and a gear 152 to which an output from the gear box 149 is transmitted, and an LD flexible substrate (lens drive flexible substrate) 155 is attached to the motor 153. Further, the lens drive unit 157 has a projection 156 projecting toward the front side of the first zoom frame 31 along the axis thereof.
Further, the first zoom frame 31 has a helicoid 151 defined on the front side of the inner circumference thereof along its circumferential direction and a projection 150 projecting in an inside diameter direction is formed at an edge portion of the helicoid 151 and further an arm 154 is disposed on the inside of the first zoom frame 31 to guide the LD flexible substrate 155.
The first group frame 38 is mounted on the screw frame 142 through the screw portion 39 thereof threadedly engaged with the screw portion 143 of the screw frame 142 and the screw frame 142 is mounted on the first zoom frame 31 through the helicoid 145 thereof threadedly engaged with the helicoid 151 of the first zoom frame 31.
When a focusing operation is carried out in the arrangement shown in
When focusing is effected to an object very near to the camera, the screw frame 142 rotates in the direction of an arrow B so that the projection 147 is butted against the projection 156 of the first zoom frame 31 and acts as a stopper.
Further when focusing is effect to an object at an indefinite distance, the screw frame 142 rotates in the direction of an arrow A so that the projection 146 is abutted against the projection 150 to act as a stopper.
The lens drive unit 157 includes the motor 153 as the drive source, a pinion gear 175 mounted on the output shaft of the motor 153, two gears 181, 174 meshed with the pinion gear 175, the gear box 149 employing two-staged planetary gear mechanisms for transmitting a drive force from the gear box 149, the gear 152 to which an output from the gear box 149 is transmitted to rotate the screw frame 142, a disk 176 having a plurality of slits 176b circumferentially arranged and disposed on the lower surface of the gear 181 in the figure and a C-shaped photointerrupter 177 disposed to hold the disk 176 vertically.
An end of the LD flexible substrate 155 is divided into two ends and one of them 155b is attached to the photointerrupter 177 and the other end 155a is attached to the motor 153. The LD flexible substrate 155 is attached to the arm 154 circumferentially extending from the lens drive unit 57 and supported thereby.
When the lens drive unit 157 is driven, power is fed to the motor 153 through the LD flexible substrate 155 first and when the motor 153 rotates, the gears 181, 174 are rotated by the pinion gear 175.
The drive force of the gear 174 is transmitted to the gear 152 through the gear box 149. Since the gear 152 is meshed with the internal gear 144 disposed on the screw frame 142, the screw frame 142 is rotated to carry out focusing as described above.
Further, when the gear 181 rotates, the disk 176 is also rotated. Since one of the two projections 177a, 177b of the C-shaped photointerrupter 177 is provided with a light emitting element and the other is provided with a light receiving element, when the slits 176b pass between the projection 177a and the projection 177b of the photointerrupter 177, light emitted by the light emitting element is received by the light receiving element and an electric power generated by the photo-to-electro conversion executed by the light receiving elements is transmitted to the end 155b of the LD flexible substrate 155. On the other hand, when the portion 176a of the disk 176 without the slits passes between the projection 177a and the projection 177b of the photointerrupter 177, since light emitted from the light emitting element is interrupted and no electric power is generated in the light receiving element, no electric power is transmitted to the end 155b of the LD flexible substrate 155.
Therefore, a pulse wave flows to the end 155b of the LD flexible substrate 155 by the rotation of the disk 176. The number of the pulses is counted by a not shown counter and counting is executed by counting an instant at which an electric current flows to the motor 153 from a nearest state as a zero pulse.
Further, focusing is controlled to stop the screw frame 142 at a position to be focused without error in such a manner that a voltage imposed on the motor 153 is reduced a few pulses before the position so that a brake is applied after the rotational speed of the motor 153 is reduced.
As shown in
Further, the lens barrel includes a flexible printed substrate for diaphragm 18 having an end connected to the diaphragm of the fourth group frame 13 and the lens driving flexible printed substrate 155 for executing focusing having an end connected to the lens drive unit 157.
These two flexible printed substrates 18, 155 enter the lens barrel from the outside thereof through a gap between the lens plate 46 and the fixed frame 34, travel along the lens plate 46 toward the optical axis at the center of the lens barrel in an overlapped state, are bent forwardly on the outer circumference side of the key 40, extend forwardly along the guide groove 40b defined to the key 40 (refer to
The flexible printed substrate 155 is guided by the arm 154 (refer to
The flexible printed substrate for diaphragm 18 is bent rearwardly after passing through the U-shaped bent portion and then connected to the stepping motor 17 (refer to
On the other hand, after the lens drive flexible printed substrate 155 passes through the U-shaped bent portion, it is connected to the motor 153 provided with the lens drive unit 157 and the photointerrupter 177 while supported by the arm 154 substantially circumferentially extending from the lens drive unit 157.
When the lens barrel as described above is zoomed, the cam frame 24 is extended with respect to the fixed frame 34 and the first zoom frame 31 is extended with respect to the fixed frame 34 and also with respect to the cam frame 24, as shown in FIG. 15. Thus, the fourth group frame 13 is relatively extended with respect to the respective frames 34, 24 and 31 as shown in the figure.
When the zooming operation is effected as described above, the U-shaped bent portions of the flexible printed substrate for diaphragm 18 and the lens drive flexible printed substrate 155 are moved forwardly and disposed as shown in FIG. 15.
In the retracted state and at the telephoto end, these two flexible printed substrates 18, 155 are disposed so that they do not overlap each other at the U-shaped bent portions thereof as shown in FIG. 16 and
More specifically, the flexible printed substrate for diaphragm 18 and the lens drive flexible printed substrate 155 have narrow width portions 190a, 191a, respectively which are arranged such that one of them is disposed by being biased on the right side and the other is disposed by being biased on the left side at the U-shaped bent portion so that they do not overlap each other in a thickness direction.
With this arrangement, even if the first zoom frame 31 and the fourth group frame 13 move, a resistance applied the U-shaped bent portions can be reduced.
Further, a fine gap is formed between the narrow width portion 190a at the U-shaped bent portion of the lens drive flexible printed substrate 155 and the narrow width portion 191a at the U-shaped bent portion of the flexible printed substrate for diaphragm 18 so that no friction is generated by the contact between flexible printed substrates.
Further, a lubrication processing may be applied to the portion where the lens drive flexible printed substrate 155 is in contact with the flexible printed substrate for diaphragm 18 by coating lubricating grease or the like to a portion thereof to lower a friction resistance therebetween.
As shown in
The cams 101, 103 and 105 of the cams on the inner circumference have the same cam configuration and are disposed at positions substantially equally divided in a circumferential direction, respectively.
The cam 102 crosses the cam 101 at a cam follower introducing portion 310.
The cams 106, 107 and 108 disposed on the outer circumference have the same cam configuration and cam 107 is divided at a portion shown by numeral 300 midway thereof and disposed as the cam 109 from a portion shown by numeral 301.
Further, holes are drilled at the positions where the cams disposed on the inner circumference cross the cams disposed on the outer circumference. For example, a hole--not shown--is drilled at the position where the cam 103 on the inner circumference is across the cam 106 on the outer circumference.
The depth of the cam groove of each of the bottomed cams disposed on the cam frame 24 is set such that the sum of the depth of the cam groove on the inner circumference and the depth of the cam groove on the outer circumference is smaller than the wall thickness of the cam frame 24.
The three pins 3 projecting from the circumference of the second group frame 1 are engaged with the three cams 101, 103 and 105, the pin 22 disposed on the fifth group frame 19 is engaged with the cam 100, the pin 15 disposed on the fourth group frame 13 is engaged with the cam 102 and the pin 12 disposed on the third group frame 5 is engaged with the cam 104.
Further, the three pins 50, 51 and 52 integrally disposed on the first zoom frame 31 are engaged with the three cams 106, 108 and 109 on the outer circumference, respectively and the pin 32 disposed on the first zoom frame 31 as a separate member is engaged with the cam 107.
Although the cams 106, 108 are engaged with the pins 50 and 51 in the overall stroke thereof, respectively, the pins 32 is removed from the cam 107 at the portion shown by numeral 300. Substantially at the same time, the pin 52 is engaged with the cam 109 so that the three cams are engaged with the three pins at all times in the cam frame 24 and the first zoom frame 31.
On the other hand, the three cams 112 each having the same cam configuration are disposed on the inner circumference of the fixed frame 34 at the positions substantially equally divided in a circumferential direction. The three pins 27 projecting from the outer circumference of the cam frame 24 are engaged with these three cams 112, respectively.
When the lens barrel is in the retracted state, the three pins 3 provided with the second group frame 1 are engaged at the positions of cam ends 101a, 103a and 105a, respectively, the pin 12 provided with the third group frame 5 is engaged at the position of a cam end 104a, the pin 15 is provided with the fourth group frame 13 is engaged at the position of a cam end 102a and the pin 22 provided with the fifth group frame 19 is engaged at the position of a cam end 100a.
Further, the three pins 50, 51 and 52 provided on the first zoom frame 31 are engaged at the positions of cam ends 106a, 108a and 109a. The pin 27 disposed on the outer circumference of the cam frame 24 is engaged at the position of a cam end 112a.
At that time, the first group frame 38, the second group frame 1, the third group frame 5, the fourth group frame 13 and the fifth group frame 19 have a positional relationship shown in
When the cam frame 24 rotates, it moves along the cams 112 of the fixed frame 34, the second group frame 1 moves along the cams 101, 103 and 105 of the cam frame 24, the third group frame 5 moves along the cam 104 of the cam frame 24, the fourth group frame 13 moves along the cam 102 of the cam frame 24, and the fifth group frame 19 moves along the cam 100 of the cam frame 24.
Although the pin 3 disposed on the second group frame 1 is unstable at the position of the cam follower introducing portion 310 where the cam 101 crosses the cam 103, since the other two pins 3 are engaged with the cams 103, 105, respectively, the cam follower introduction portion 310 can be passed through without serious affect to operation.
When the pins provided with the respective frames pass through a hole such as that denoted by numeral 110 where the cam on the inner circumference of the cam frame 24 is across the cam on the outer circumference thereof, the pin securely moves on the cam because the sum of the depth of the cam groove on the inner circumference side and the depth of the cam groove on the outer circumference side is set smaller than the wall thickness of the cam frame 24 as described above so that the pins are not simultaneously engaged at the hole.
When the lens barrel is located at the zoomed wide end, the three pins 3 of the second group frame 1 are engaged at the positions of inflection points 101b, 103b and 105b, respectively, the pin 12 of the third group frame 5 is engaged at the position of an inflection point 104b, the pin 15 of the fourth group frame 13 is engaged at the position of an inflection point 102b, and the pin 22 of the fifth group frame 19 is engaged at the position of an inflection point 100b.
Further, the pins 50, 51 of the first zoom frame 31 are engaged at the positions of inflection points 106b and 108b, respectively and the pin 32 of the first zoom frame 31 is engaged at the position of an inflection point 107b. In addition, the pin 27 of the cam frame 24 is engaged at the position of an inflection point 112b.
At that time, the first group frame 38, the second group frame 1, the third group frame 5, the fourth group frame 13 and the fifth group frame 19 have a positional relationship shown in
When the lens barrel is located at the zoomed telephoto end, the three pins 3 of the second group frame 1 are engaged at the positions of cam ends 101c, 103c and 105c, the pin 12 of the third group frame 5 is engaged at the position of a cam end 104c, the pin 15 of the fourth group frame 13 is engaged at the position of a cam end 102c and the pin 22 of the fifth group frame 19 is engaged at the position of a cam end 100c.
Further, the pins 50 and 51 of the first zoom frame 31 are engaged at the positions of cam ends 106c and 108c, respectively and the pin 32 of the first zoom frame 31 is engaged at the position of a cam end 107c. In addition, the pin 27 of the cam frame 24 is engaged at the position of a cam end 112c.
At that time, the first group frame 38, the second group frame 1, the third group frame 5, the fourth group frame 13 and the fifth group frame 19 has a positional relationship shown in
When the lens barrel is in the standard state, the three pins 3 of the second group frame 1 are engaged between the inflection point 101b and the cam end 101c, between the inflection point 103b and the cam end 103c and between the inflection point 105b and the cam end 105c, respectively, the pin 12 of the third group frame 5 is engaged between the inflection point 104b and the cam end 104c, the pin 15 of the fourth group frame 13 is engaged between inflection point 102b and the cam end 102c, and the pin 22 of the fifth group frame 19 is engaged between the inflection point 100b and the cam end 100c.
Further, the pins 50 and 51 of the first zoom frame 31 are engaged between the inflection point 106b and the cam end 106c and between the inflection point 108b and the cam end 108c, respectively and the pin 32 of the first zoom frame 31 is engaged between the inflection point 107b and the cam end 107c. In addition, the pin 27 of the cam frame 24 is engaged between the inflection point 112b and the cam end 112c.
At that time, the first group frame 38, the second group frame 1, the third group frame 5, the fourth group frame 13 and the fifth group frame 19 have a positional relationship shown in
Next, a flow diagram for zooming the lens barrel from the retracted state to a wide side will be described with reference to FIG. 24.
When a not shown power switch provided with the camera is turned on, a voltage is applied to the zoom motor 45 to drive it clockwise (step S1). At that time, the lens barrel is displaced in the wide direction and a signal is outputted from the photointerrupter (abbreviated as PI in FIG. 24), 239, a not shown timer is reset (step S2), and the monitor of the photointerrupter 239 and an output from the photoreflector (abbreviated as PR in
When an output from the photoreflector 48 is switched to high (H) (step S3), braking is applied to the zoom motor 45 (step S4) and it is confirmed by the output from the photointerrupter 239 that the zoom motor 45 is stopped. At that time, the content of the output counter of the photointerrupter 239 is rewritten to the predetermined "number of pulses (W+1) at the switched position of the photoreflector 48" (step S5).
Next, a voltage is applied to the zoom motor 45 to drive is counterclockwise (step S6) and when the falling down (i.e., falling edge) of the photointerrupter 239 is sensed (step S7), the content of the counter of the photointerrupter 239 is decremented by 1 (step S8).
Then, when it is sensed that the content of the counter of the photointerrupter 239 becomes W+α which indicates the position just in front of the wide position by an amount corresponding to the given pulse (α) (Step S9), a voltage for driving the zoom motor 45 is reduced (step S10) and when it is confirmed that content of the counter of the photointerrupter 239 becomes the predetermined value W after the speed of the lens barrel is reduced (step S11), braking is applied to the zoom motor 45 (step S12) to stop the lens barrel at a target wide position.
Further, when an output from the photoreflector 48 is low (L) at step S3, the rising (rising edge) up of the photointerrupter 239 is sensed (step S13), and when it is sensed, the timer is reset (step S14) and the process returns to step S3. Further, when a predetermined time elapses without sensing the rising up of the photointerrupter 239 (step S15), it is determined to be extraordinary.
Further, when a predetermined time elapses without sensing the falling down of the photointerrupter 239 at step S7 (step S16), it also determined to be extraordinary.
Next, a flow for zooming the lens barrel from the wide side to the telephoto side will be described with reference to FIG. 25.
When the not shown power switch provided with the camera is turned on, a voltage is applied to the zoom motor 45 to drive it clockwise (step S21) and the lens barrel starts to be displaced in the telephoto direction. At that time, a signal is output from the photointerrupter 239, the timer is reset (step S22), and the monitor of the photointerrupter 239 and an output from the photoreflector 48 is started.
Although an output from the photoreflector 48 is switched to high (H) in the midway of the process, at that time the content of the output counter of the photointerrupter 239 is rewritten to the predetermined "number of pulses (W+1) at the switched position of the photoreflector 48".
An output from the photoreflector 48 is switched to low (L) in the vicinity of the telephoto side (step S23). At that time the content of the output counter of the photointerrupter 239 is rewritten to the predetermined "number of pulses (T-1) at the switched position of the photoreflector 48" (step S24). When it is sensed that the content of the counter of the photointerrupter 239 becomes T-α which indicates the position just in front of the telephoto position by an amount corresponding to the given pulse (α) (step S25), a voltage for driving the zoom motor 45 is reduced (step S26) and when it is confirmed that content of the counter of the photointerrupter 239 becomes T after the speed of the lens barrel is reduced (step S27), braking is applied to the zoom motor 45 (step S28) to stop the lens barrel at a target telephoto position.
Further, when an output from the photoreflector 48 is high (H) at step S23, the rising up of the photointerrupter 239 is sensed (step S29), and when it is sensed, the timer is reset (step S30) and the process returns to step S23. Further, when a predetermined time elapses without sensing the rising up of the photointerrupter 239 (Step S31), it is determined to be extraordinary.
Next, a flow for zooming the lens barrel from the telephoto side to an arbitrary zoom position will be described with reference to FIG. 26.
When a zoom switch is turned on, a voltage is applied to the zoom motor 45 to drive it counterclockwise (step S41) and the lens barrel starts to be displaced in the wide direction. At that time, a signal is output from the photointerrupter 239, the timer is reset (step S42), and the monitor of the photointerrupter 239 and an output from the photoreflector 48 is started.
When it is sensed in the midway of the process that an output from the photoreflector 48 is switched to high (H) (step S43), the content of the output counter of the photointerrupter 239 is rewritten to the predetermined "number of pulses (T-1) at the switched position of the photoreflector 47" (step S44). Thereafter, when the zoom switch is turned off in the midway of the process (step S45), braking is applied to the zoom motor (step S46) to stop the lens barrel.
When the zoom switch is not turned off in the midway of the zooming process (step S45), an output from the photoreflector 48 is switched to low (L) at a position just in front of the wide position. At that time the content of the output counter of the photointerrupter 239 is rewritten to the predetermined "number of pulses (W+1) at the switched position of the photoreflector 48" (step S50).
When it is sensed that the content of the counter of the photointerrupter 239 becomes W+α which indicates the position just in front of the wide position by an amount corresponding to the given pulse (α) (step S51), a voltage for driving the zoom motor 45 is reduced (step S52) and when the content of the counter of the photointerrupter 239 becomes W after the speed of the lens barrel is reduced (step S53), brake is applied to the zoom motor 45 (step S54) to stop the lens barrel at a target wide position.
Further, when an output from the photoreflector 48 is low (L) at step S43, the rising up of the photointerrupter 239 is sensed (step S47), and when it is sensed, the timer is reset (step S48) and the process returns to step S43. Further, when a predetermined time elapses without sensing the rising up of the photointerrupter 239 (step S49), it is determined to be extraordinary.
Next, a flow when the lens barrel is retracted will be described with reference to FIG. 27.
When the power switch is turned on, a voltage is applied to the zoom motor 45 to drive it counterclockwise (step S61) and the lens barrel starts to be displaced in a retracting direction. At that time a signal is output from the photointerrupter 239, the timer is reset (step S62), and the monitor of the photointerrupter 239 and an output from the photoreflector 48 is started.
When an output from the photoreflector 48 is low (L) (step S63), the content of the output counter of the photointerrupter 239 is rewritten to the predetermined "number of pulses (W+1) at the switched position of the photoreflector 48" (step S64).
When it is sensed that the content of the counter of the photointerrupter 239 becomes α which indicates the position just in front of the retracted position by an amount corresponding to the given pulse (α) (step S65), a drive voltage applied to the zoom motor 45 is reduced (step S66) and when it is sensed that the content of the counter of the photointerrupter 239 becomes 0 after the speed of the lens barrel is reduced (step S67), braking is applied to the zoom motor 45 (step S68) to stop the lens barrel at a target retracted position.
Further, when an output from the photoreflector 48 is high (H) at step S63, the rising up of the photointerrupter 239 is sensed (step S69), and when it is sensed, the timer is reset (step S70) and the process returns to step S63. Further, when a predetermined time elapses without sensing the rising up of the photointerrupter 239 (step S71), it is determined to be extraordinary.
As described above, according to the embodiment, since there are provided the fixed frame having the internal cam, the cam frame for moving the lens barrel group holding frames in the optical axis direction while being rotated by the internal cam on the inner circumference side thereof, the long shaft pinion gear for driving the internal gear of the cam frame and the key member for regulating the rotation of the lens group holding frames, a lens barrel having a large amount of movement in the optical axis direction can be realized by the smaller number of frames and thus when the lenses are retracted, the length of the lens barrel can be shortened.
With respect to the disposition of the cams of the cam frame, since the bottomed cams are disposed on both sides of the frame, i.e. on the inner circumference and the outer circumference and the cams are disposed in such a manner that the cams on the inner circumference are across the cams on the outer circumference at at least one position and one of the cams is divided at at least one position, the cams can be effectively disposed in a small space and the size of the cam frame can be reduced in the optical axis direction. As a result, the size of the zoom lens barrel can be reduced.
With respect to the method of supporting the lens holding frames for holding the lens groups, since the zoom lens barrel provides the bearings with the lens holding frame serving as the reference for supporting the rods, the rods are provided with the other lens holding frames and the rods are disposed at the positions substantially equally divided in a circumferential direction, the rods can be effectively supported in a small space. As a result, the length of the zoom lens barrel can be shortened in the retracted state.
With respect to the flexible printed substrates each having at least one U-shaped bent portion, since a plurality of the flexible printed substrates are arranged such that they do not overlap each other at the U-shaped bent portions, a resistance which is applied to the relatively moving members such as the lens holding frames and the like by the U-shaped bent portions can be reduced and as a result the above members can be smoothly moved.
Further, since the rotation of the frames for holding the lens groups is stopped and the strength of the lens barrel is reinforced by the key composed of the same member, the arrangement of the lens barrel can be simplified. In addition, as a method of stopping rotation, since the lens holding frame whose rotation is stopped by the key regulates the rotation of the other lens holding frames, the rotation of the frames having a large amount of movement can be stopped using a short key, whereby the length of the lens barrel can be shortened in the retracted state.
In this invention, it is apparent that working modes different in a wide range can be formed on this basis of this invention without departing from the spirit and scope of the invention. This invention is not restricted by any specific embodiment except as may be limited by the appended claims.
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| Oct 01 2003 | OLYMPUS OPTICAL CO , LTD | Olympus Corporation | CHANGE OF NAME SEE DOCUMENT FOR DETAILS | 014523 | /0726 |
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