JPH07191250A - Lens barrel - Google Patents

Abstract

PURPOSE:To provide a lens barrel by which large displacing amount in an optical axis direction is realized with few frame members and whose length in the case of collapsing is short. CONSTITUTION:This lens barrel is provided with a fixed frame 34; lens holding frames holding lens groups arranged on the inner periphery of the fixed frame, such as a 2nd group frame 1, a 3rd group frame 5, a 4th group frame 13, and a 5th group frame 19; a cam frame 24 coupled with the inner periphery of the fixed frame 34 through a cam and advanced/retreated in the optical axis direction when it is turned about the fixed frame 34; and keys 40 and 42 regulating the turning of the lens holding frame about the fixed frame 34. Furthermore, it is provided with a cam mechanism consisting of blind cams 25 and 26 provided between the cam frame 24 and the lens holding frame, advancing/ retreating the lens holding frame in the optical axis direction by the turning of the cam frame 24 about the fixed frame 34, and engraved on the cam frame 24; an internal gear 29 provided on the inner peripheral surface of the cam frame 24; and a pinion gear 43 transmitting driving force from a zoom motor 45 to the gear 29 so that the cam frame 24 may be turned around an optical axis, and extended in the optical axis direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens barrel, and more particularly to a lens barrel in which a plurality of lens groups are arranged so as to be movable back and forth in the optical axis direction.

[0002]

2. Description of the Related Art Conventionally, there are various lens barrels for zooming by rotating a cam frame housed inside a fixed frame and moving a holding frame of a lens group in the optical axis direction. Proposed.

As an example of such a device, Japanese Patent Laid-Open No. 53-53
In Japanese Patent Laid-Open No. 102030, there is described one having two fixed frames, in which the first lens group is rotationally slid, and the cam frame is driven by the rotational amount to drive the other lens groups. There is.

Further, Japanese Utility Model Publication No. 50-14511 includes a fixed frame, a cam frame which moves while rotating along a cam of the fixed frame, and a frame driven by the cam frame. A lens barrel in which a rotation stopper of a frame is provided on the fixed frame is described.

In the zoom lens barrel for which various types have been proposed as described above, if the length of the lens barrel in the collapsed state is reduced in order to reduce the size, the amount of movement of the lens group increases. Therefore, a longer cam frame is needed.

Further, as described in Japanese Patent Application Laid-Open No. 3-180822, when the length of the lens barrel when retracted is shortened by using a short cam frame, the lens frame unit reaches a certain position. Two mechanisms are required, a mechanism for feeding and a mechanism for feeding from that position to the feeding completion position.

[0007]

However, the structure described in Japanese Patent Laid-Open No. 53-102030 has a complicated structure and requires many parts. Further, since the cam frame does not slide, The amount of lens movement will be determined by the length of the cam frame.

Further, in the one disclosed in Japanese Utility Model Publication No. 50-14511, since the fixed frame is provided with the rectilinear groove and the cam for the cam frame, the cam arrangement is restricted.

Further, when a cam frame that is long in the axial direction is used for retracting the lens group having the increased movement amount, if the balance between the movement amount of the lens and the length of the cam frame is lost, the lens is moved to the lens frame. However, the cam frame remains protruding from the lens frame.

When the cam frame is shortened so that the cam frame can be housed in the lens barrel when the lens is housed therein, as in the above-mentioned Japanese Patent Laid-Open No. 3-180822, Two mechanisms are required for feeding,
The configuration of the zoom lens barrel becomes complicated.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a lens barrel which can realize a large displacement amount in the optical axis direction with a small number of frame members.

[0012]

In order to achieve the above object, the lens barrel according to the present invention comprises a fixed frame and a plurality of a plurality of lenses arranged on the inner circumference of the fixed frame so as to be movable back and forth in the optical axis direction. A lens group, a lens holding frame that holds at least one lens group of the plurality of lens groups, a cam connection with the inner circumference of the fixed frame, and the optical axis direction is rotated with respect to the fixed frame. A cam frame that is moved forward and backward, a key member that restricts rotation of the lens holding frame with respect to the fixed frame, and a lens that is provided between the cam frame and the lens holding frame and that is rotated by the cam frame with respect to the fixed frame. A cam mechanism for advancing and retracting the holding frame in the optical axis direction, an internal gear provided on the inner peripheral surface of the cam frame, and a drive force from a drive source transmitted to the internal gear to move the cam frame to the optical axis. With a pinion gear extending in the optical axis direction to rotate around It is provided.

[0013]

The pinion gear extending in the optical axis direction transmits the driving force from the drive source to the internal gear provided on the inner peripheral surface of the cam frame to rotate the cam frame around the optical axis, A cam frame that is cam-coupled to the inner circumference of the fixed frame advances and retreats in the optical axis direction by being rotated with respect to the fixed frame, and a cam mechanism provided between the cam frame and the lens holding frame is provided. The rotation of the cam frame with respect to the fixed frame advances and retracts the lens holding frame in the optical axis direction, and the key member restricts the rotation of the lens holding frame with respect to the fixed frame.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a perspective view showing a structure for mounting a lens barrel of an embodiment of the present invention on a camera body, and FIG. 3 is a vertical sectional view of the camera.

The camera of this embodiment has a camera body 74.
And a front plate 75 having a mirror 75a and a finder 75b, which is fixed by screwing a screw 76 from the rear side to the front side of the camera body 74, and a screw 72 is screwed to a position in front of the front plate 75. The lens unit 7 is fixed to the camera body 74 by fitting the lens unit 7 to the front side.
The lens plate 46 for reinforcing the strength of the entire lens barrel fixing the lens barrel 3, the rear cover 77 fitted from the rear side so as to abut the camera body 74 via the convex portion 77a, and the lens plate 46. The front cover 78 fitted from the front side so as to abut via the convex portion 78a constitutes a main part.

FIG. 1 is an exploded perspective view showing the zoom lens barrel of this embodiment in an expanded state in the optical axis direction, and FIG. 4 is an exploded perspective view showing details of essential parts of a lens holding frame.

The zoom lens barrel includes, in order from the front side (subject side) along the optical axis, the first group frame 38 holding the first group lens, and the second group frames 1, 3 holding the second group lens. It has a third group frame 5 holding a group lens, a fourth group frame 13 holding a fourth group lens, and a fifth group frame 19 holding a fifth group lens.

The second group frame 1, the third group frame 5, the fourth group frame 13, 5
A cam frame 24 is arranged on the outer peripheral side of the group frame 19, and a first zoom frame 31 into which the first group frame 38 is screwed via a screw portion 39 is arranged outside the cam frame 24. A fixed frame 34 is arranged on the outer peripheral side of the first zoom frame 31, and the fixed frame 34 is fixedly attached to the lens plate 46.

The second group frame 1 is provided with three outwardly projecting three pins 3 at three circumferentially divided positions on the circumferential surface thereof, and the pins 3 are forwardly projected in the optical axis direction. On the side (subject side), three protrusions 30 are provided at equal positions in the circumferential direction, a key groove 4 is provided parallel to the optical axis, and the rod 2 is further bonded.

In the third group frame 5, substantially cylindrical bearings 7, 8 and 9 having sleeves 6 at both ends are arranged at circumferentially equally divided positions, and the bearings 8 among them are axially arranged. A protruding portion 23 protruding to the rear side (camera body side) is provided, and the pin 12 protruding in the outer diameter direction is integrally provided on the protruding portion 23. Further, a guide protrusion 10 extending rearward in the optical axis direction is provided on the third group frame 5 at a position between the bearing 7 and the bearing 8 along the circumferential direction, and the guide protrusion 10 is provided between the bearing 8 and the bearing 9. A guide protrusion 11 extending rearward of the optical axis is provided at the position.

The fourth group frame 13 has a pin 15 integrally projecting from its peripheral surface in the outer diameter direction, and a groove 16 for preventing rotation is formed on the same peripheral surface to further prevent light. A rod 14 is bonded to the front side in parallel with the axis. A motor 17 for adjusting the diaphragm is attached to the fourth group frame 13, and a belt-shaped substrate 18 extends from the motor 17.

In the fifth group frame 19, the pin 22 is integrally projected in the outer diameter direction and the groove portion 20 for stopping rotation is provided.
Is provided, and a rod 21 that is forward and parallel to the optical axis is further bonded.

The cam frame 24 is a cylindrical member in which several bottomed cams 26 constituting a cam mechanism are engraved on the inner peripheral surface of the cam frame 24. The inner peripheral surface of the cam frame 24 is on the rear side of the optical axis (on the side of the photographer). ) Is provided with a partial internal gear 29 in the circumferential direction. Further, on the outer peripheral surface of the cam frame 24, several bottomed cams 25 which also constitute the cam mechanism are engraved, and an encoder 28 is adhered, and three pins are provided from the end portion on the rear side of the optical axis. Two
7 is integrally projected.

The first zoom frame 31 has three inner peripheral surfaces.
A straight groove 33 is formed at three equally divided positions in the circumferential direction, three pins 50 are integrally projected from the inner peripheral surface, and a substantially rectangular projection is formed from the rear end. The portion 49 extends in the axial direction, and the projection portion 49 is provided with a pin 32 separately from the first zoom frame 31. Further, pins 51 and 52 are provided on the inner peripheral surface of the first zoom frame 31 so as to project.

The fixed frame 34 is a cylindrical member having a cam 112 on the inner peripheral surface, a ring 36 is fitted to the end portion on the front side in the optical axis direction, and a photo reflector (PR) is arranged on the outer peripheral surface.
A substrate 35 having 48 is attached. Further, from the rear end surface of the fixed frame 34 in the optical axis direction, several bosses 37 are provided so as to project in the circumferential direction.

Further, the first group frame 38 is provided with a threaded portion 39 for attachment to the first zoom frame 31 on the peripheral surface on the front side of the optical axis.

The lens plate 46 is a plate-shaped member having holes 47 at four corners, and has a thin light-shielding groove 4 in a direction perpendicular to the optical axis.
A key 40 in which a large number of 1 are engraved and a key 42 to which a pinion gear 43 extending in the optical axis direction is attached are attached so as to be perpendicular to the front surface of the lens plate 46. There is. Further, a zoom motor 45 as a drive source and a second gear box 44 having a gear train for transmitting the driving force of the zoom motor 45 are attached to the lens plate 46, and a final gear of this gear train is attached. Engages with the pinion gear 43 attached to the key 42.

Next, the alignment of the lens holding frames will be described. The third group frame 5 is movable in the axial direction with respect to the second group frame 1 by inserting the rod 2 into the bearing 8, and the bearings 7 and 9 restrict the radial direction to prevent the movement of the second group frame 1. The radial position with respect to the group frame 1 is determined.

The fourth group frame 13 is axially movable with respect to the third group frame 5 by inserting the rod 14 into the bearing 7, and the groove 16 and the guide projection 11 are fitted together. As a result, the position in the radial direction with respect to the third group frame 5 is determined.

The fifth group frame 19 is axially movable with respect to the third group frame 5 by inserting the rod 21 into the bearing 9, and the groove 20 and the guide projection 10 are fitted together. The position in the radial direction is determined with respect to the third group frame 5.

That is, the positions of the fourth group frame 13 and the fifth group frame 19 are determined with respect to the third group frame 5, and the position of the third group frame 5 is determined with respect to the second group frame 1, whereby the position of each lens holding frame is determined. We are making adjustments.

Positioning of other frame members is performed as follows. By engaging pins 3, 12, 15, and 22 with a cam 26 on the inner peripheral surface of the cam frame 24, the cam frame 24 is different from the second group frame 1, the third group frame 5, the fourth group frame 13, and the fifth group frame 19 in To determine the radial position.

Further, in the cam frame 24, the pin 25 of the first zoom frame 31 is engaged with the cam 25, and in the second group frame 1, the projection 30 is engaged with the rectilinear groove 33 of the first zoom frame 31. By matching, the position in the radial direction with respect to the first zoom frame 31 is determined. The position of the first group frame 38 is determined by screwing a screw portion 39 into the tip portion of the first zoom frame 31.

Further, the cam frame 24 has the pin 27 fixed to the fixed frame 3
By engaging with the cam 112 of No. 4, the position in the radial direction with respect to the fixed frame 34 is determined.

In the fixed frame 34, the boss 37 is attached to the lens plate 4.
The position of the second group frame 1 is determined by fitting the key group 6 into the key groove 6, and the rotation of the second group frame 1 around the optical axis is restricted by fitting the key 40 into the key groove 4 of the second group frame 1.

Next, the structure of the zoom gear attached to the lens plate 46 will be described with reference to FIG. On the front surface (lower surface in FIG. 5) of the lens plate 46 for fixing the lens barrel, the key 40 for restricting rotation of the second group frame 1 around the optical axis and the cam frame 24 for rotating. A pinion gear 43 having an axial length is arranged. Also, the lens plate 4
On the rear surface (upper surface in FIG. 5) of 6, is a zoom motor 45,
A first gear box 241 including three stages of planetary gear mechanisms,
A second gear box 44 including a train of external gears is arranged.

The zoom motor 45 constitutes a first stage planetary gear mechanism in the first gear box 241 by using a pinion gear attached to its output shaft as a sun gear.

The last-stage carrier in the first gear box 241 meshes with the external gear in the second gear box 44, and a plurality of slits are formed along the circumferential direction via the gear 235. It is meshed with a gear 236 having a circular plate 237 integrally and rotatably on its rear surface.

Further, the gear 235 is integrally provided with a gear 243 which is coaxial and has different diameters, and the gear 236 is coaxial with the gear 24 which has different diameters.
4 is provided separately on the opposite front surface with the lens plate 46 interposed therebetween. The gear 243 and the gear 244 mesh with each other, and the gear 244 meshes with a gear 242 having a different diameter provided at the base end of the pinion gear 43 having the axial length.

A U-shaped photo interrupter (PI) 239 is arranged so as to sandwich the disk 237, and a flexible substrate 238 is attached to the photo interrupter 239.

When the zoom motor 45 rotates, the planetary gear mechanism in the first gear box 241 is driven, and then the gear train in the second gear box 44 is driven. Further, the gear 236 and the disc 237 rotate via the gear 235.

When the slit of the disk 237 passes through the photo interrupter 239, light is transmitted and a signal flows through the flexible substrate 238. On the other hand, when the non-slit portion of the disc 237 passes through, the light is blocked and the signal does not flow to the flexible substrate 238. Therefore, when the disk 237 rotates, the flexible substrate 238
A pulse wave is designed to flow through.

On the other hand, when the gear 243 rotates with the rotation of the gear 235, the gear 2 moves through the gear 244.
42 rotates, and along with this, the pinion gear 43 of the axial length
Is driven to rotate.

As shown in FIG. 1, the pinion gear 43 meshes with the internal gear 29 of the cam frame 24, and the pin 27 of the cam frame 24 engages with the cam 112 of the fixed frame 34. Therefore, when the pinion gear 43 rotates, the cam frame 24 moves forward along the cam 112 while rotating around the optical axis.

The second group frame 1, the third group frame 5, the fourth group frame 13,
Since the fifth group frame 19 is restricted from rotating about the optical axis by the key 42, it moves back and forth along the cam 26 on the inner peripheral surface of the cam frame 24 without rotating.

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 the light emitted from the light emitting element is reflected by the outer peripheral surface of the cam frame 24 and received. It is designed to enter the element. Cam frame 2
The encoder 28 provided in FIG. 4 has a higher light reflectance than other portions of the peripheral surface of the cam frame 24, and when the encoder 28 passes a position corresponding to the photo reflector 48, The signal output from the photo reflector 48 is changed.

When the cam frame 24 rotates and the one end 28a of the encoder 28 passes through the photo reflector 48,
+1 (several pulses from the wide (WIDE) end), and when the other end 28b of the encoder 28 passes through the photo reflector 48 is T-1 (several pulses before the tele (TELE) end), and these are described above. 239 reset position.

During zooming from the retracted position to the wide end or the tele end and from the standard (STD) to the wide end or the tele end, the photo interrupter 239 must be passed through the reset position of the photo interrupter 239 without fail. By eliminating the variation of the pulses, zooming is performed so that the cam frame 24 stops at the correct position.

FIG. 6 is an exploded perspective view showing the lens drive unit 157, the screw frame 142, and the first group frame 38 provided in the first zoom frame 31 in the optical axis direction. As shown in the figure, a first group frame 38 having a screw portion 39 on the outer periphery is arranged in front of the screw frame 142, and the screw frame 14
The lens drive unit (LD unit) 15 is behind 2
A first zoom frame 31 having 7 mounted on the inner peripheral surface side is arranged.

The screw frame 142 is provided with a threaded portion 143 along the circumferential direction at the tip of the inner peripheral surface thereof, and the rear end portion of the inner peripheral surface has an inner gear within a predetermined range along the circumferential direction. 144 is provided, and a helicoid 145 is further engraved along the circumferential direction at the rear end portion of the outer peripheral surface. In addition, the screw frame 14
2 has two protrusions 146 and 147 projecting in the vicinity of the end of the inner gear 144, one of these protrusions 1
47 is provided so as to be convex in the inner diameter direction of the screw frame 142, and the other projection 146 is provided so as to be convex behind the optical axis of the screw frame 142.

On the other hand, the lens drive unit 157 attached to the inner peripheral surface of the first zoom frame 31 includes a motor 153 as a drive source and a gear box 149 incorporating a gear train for reducing the drive force from the motor 153. And the gear 15 to which the output of the gear box 149 is transmitted.
2, and an LD flexible substrate (lens driving flexible substrate) 155 is attached to the motor 153. Further, the lens driving unit 1
The projection 57 has a projection 156 that projects toward the front side of the first zoom frame 31 along the axial direction.

In the first zoom frame 31, a helicoid 151 is engraved on the front side of the inner peripheral surface along the circumferential direction, and a protruding portion which is convex in the inner diameter direction is formed at one edge of the helicoid 151. 150 is provided, and further an arm portion 154 for guiding the LD flexible substrate 155 is provided inside.

The first group frame 38 is attached to the screw frame 142 by screwing the screw portion 39 of the first group frame 38 into the screw portion 143 of the screw frame 142.
2 is attached to the first zoom frame 31 by screwing the helicoid 145 into the helicoid 151 of the first zoom frame 31.

In the structure shown in FIG. 6, when the focusing operation is performed, the motor 153 is driven and the gear 152 is rotated via the gear train in the gear box 149. Since the gear 152 meshes with the inner gear 144 of the screw frame 142, the gear 152
Is rotated, the screw frame 142 is rotated and the helicoid 151 is rotated.
Along the optical axis, the first group frame 38 is also manipulated to perform focusing.

When focusing is near, the screw frame 142 rotates in the direction of arrow B, and the projection 147 and the first
The protrusion 156 of the zoom frame 31 comes into contact with the zoom frame 31 to function as a stopper. When the focusing is infinity, the screw frame 142 rotates in the direction of arrow A,
The protrusion 146 and the protrusion 150 are in contact with each other to function as a stopper.

Details of the lens driving unit 157 described above are shown in FIG. The lens drive unit 157 includes a motor 153 as a drive source, a pinion gear 175 attached to the output shaft of the motor 153, two gears 181 and 174 meshing with the pinion gear 175, and a driving force from the gear 174. A gear box 149 using two stages of planetary gear mechanisms for transmitting the power, a gear 152 for transmitting the output of the gear box 149, a gear 152 for rotating the screw frame 142, and a gear 181. A disk 176 having a plurality of slits 176b provided along the circumferential direction, which is provided on the lower surface side in the figure;
It has a U-shaped photo interrupter 177 arranged so as to sandwich the disc 176 vertically.

The LD flexible substrate 155 is also used.
Has one end branched into two and one end 15
5b is attached to the photo interrupter 177, and the other end 155a is attached to the motor 153.
The LD flexible substrate 155 is attached to and supported by an arm portion 154 extending in the circumferential direction from the lens driving unit 157.

When driving such a lens driving unit 157, first, electric power is transmitted to the motor 153 through the LD flexible substrate 155, and when the motor 153 rotates, the pinion gear 175 causes the gear 181,
174 rotates.

The driving force of the gear 174 is transmitted to the gear 152 via the gear box 149. The gear 152 is the inner gear 14 provided on the screw frame 142.
4, the screw frame 142 rotates and the focusing is performed as described above.

When the gear 181 rotates, the disc 1
76 also rotates. U-shaped photo interrupter 1
Since the light emitting element is provided on one side and the light receiving element is provided on the other side of the two protruding portions 177 a and 177 b of 77, the slit 176 b is formed in the protruding portion 17 of the photo interrupter 177.
When light passes through between 7a and the protrusion 177b, the light emitted from the light emitting element is received by the light receiving element, and the electricity generated by photoelectric conversion in the light receiving element is transferred to the LD flexible substrate 155.
Is transmitted to the end 155b. On the other hand, when the non-slit portion 176a of the disk 176 passes between the protrusions 177a and 177b of the photo interrupter 177, the light emitted by the light emitting element is blocked and electricity is not generated in the light receiving element. Edge 15 of substrate 155
No electricity is transmitted to 5b.

Therefore, when the disc 176 rotates, a pulse wave flows through the end portion 155b of the LD flexible substrate 155. This pulse number is counted by a counter (not shown), and the moment when a current is passed through the motor 153 from the closest state is counted as 0 pulse.

Further, at the focus position, there is no error in the screw frame 1
42 so that the motor 153 is stopped from several pulses before
Focusing is controlled by lowering the voltage applied to the motor 153 to reduce the rotation speed of the motor 153 and then applying a brake.

FIG. 8 is a development view showing the cam provided on the cam frame 24, and FIG. 9 is a development view showing the cam provided on the fixed frame 34. 10 is a longitudinal sectional view along the optical axis showing the lens barrel in the collapsed state, FIG. 11 is a longitudinal sectional view along the optical axis showing the lens barrel at the wide end, and FIG. 12 is the lens barrel in the standard state. Is a longitudinal sectional view along the optical axis, and FIG. 13 is a longitudinal sectional view along the optical axis showing the lens barrel at the tele end.

As shown in FIG. 8, the bottomed cam 26 provided on the inner peripheral surface of the cylindrical cam frame 24, more specifically, the cams 100, 101, 102, 103, 104, 1
05, six bottomed cams, while the bottomed cam 25 provided on the outer peripheral surface is described in more detail below.
It consists of four bottomed cams 107, 108, and 109.

Among the cams on the inner peripheral surface, the cams 101, 103,
Numerals 105 have the same cam shape, and are arranged at approximately three equally divided positions in the circumferential direction.

The cam 102 alternates with the cam 101 in the cam follower introducing portion 310.

The cams 106, 107 provided on the outer peripheral surface,
Reference numeral 108 denotes the same cam shape, and the cam 107 is divided at a portion indicated by reference numeral 300 in the middle thereof and arranged as a cam 109 from the portion indicated by reference numeral 301.

Further, a hole is bored in a portion where the cam provided on the inner peripheral surface and the cam provided on the outer peripheral surface alternate. For example, the cam 103 on the inner peripheral surface and the cam 106 on the outer peripheral surface
A hole (not shown) is formed in a portion indicated by reference numeral 400 in which and alternate with each other.

The cam groove depth of the bottomed cam provided on the cam frame 24 is such that the sum of the depth of the inner peripheral surface side cam groove and the outer peripheral surface side cam groove is greater than the thickness of the cam frame 24. Is also made smaller.

The three cams 101, 103, 105 are engaged with the three pins 3 projecting from the peripheral surface of the second group frame 1, and the cam 100 is provided with the third group frame 5. The pin 12 provided on the cam engages with the cam 102 and the fourth group frame 1
The pin 15 provided on the No. 3 is engaged with the cam 104, and the pin 22 provided on the fifth group frame 19 is engaged with the cam 104.

Further, the three cams 106, 10 on the outer peripheral surface are provided.
The three pins 50 provided integrally with the first zoom frame 31 are engaged with 8 and 109, respectively.
A pin 32 provided separately from the first zoom frame 31 is engaged with the cam 107.

The cams 106 and 108 engage with the pin 50 in the entire stroke, but the pin 32 has the reference numeral 30.
The portion indicated by 0 is detached from the cam 107. At this time, the pins 50 are engaged with the cam 109 almost simultaneously, and the cam frame 24 and the first zoom frame 31 are always engaged with the three cams and the three pins.

On the other hand, the fixed frame 34 is provided with three cams 112 having the same cam shape on the inner peripheral surface thereof at substantially equal positions in the circumferential direction. These three cams 112 have a cam frame 24
The three pins 27 protruding from the outer peripheral surface of are engaged with each other.

When the lens barrel is in the retracted state, the three pins 3 provided on the second group frame 1 are respectively attached to the cam end 1.
01a, 103a, 105a at the positions of the third group frame 5
The pin 12 provided on the fourth group frame 13 is engaged with the pin 12 provided on the cam end 100a.
The pin 22 provided on the fifth group frame 19 is engaged at the position of the cam end 104a.

Further, the three pins 50 provided on the first zoom frame 31 are provided with the cam ends 106a and 108, respectively.
a and 109a are engaged. Furthermore, the cam frame 2
4 is provided on the outer peripheral surface of the cam end 112.
It is engaged at the position a.

At this time, the positional relationship between 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 is as shown in FIG.

When the cam frame 24 rotates, the cam frame 24 moves along the cam 112 of the fixed frame 34, the second group frame 1 moves along the cams 101, 103, 105 of the cam frame 24, and the third group The frame 5 moves along the cam 100 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 104 of the cam frame 24.

At the position of the cam follower introducing portion 310 where the cam 101 and the cam 103 alternate, the pin 3 provided on the second group frame 1 becomes unstable, but the other two pins 3 become the cams 103 and 105, respectively. Because of the engagement, it is possible to pass through the cam follower introducing portion 310 without significantly affecting the operation.

The pins provided on each frame are
When the cam on the inner peripheral side and the cam on the outer peripheral side of the cam frame 24 pass through the hole indicated by reference numeral 400, as described above, the depth of the inner peripheral cam groove and the outer peripheral cam groove are increased. The total depth is less than or equal to the thickness of the cam frame 24, and the pin is arranged so as not to engage with the hole at the same time, so that the pin moves reliably on the cam. There is.

When the lens barrel is at the wide end of the zoom, the three pins 3 of the second group frame 1 are respectively provided with inflection points 10.
The pins 12 of the third group frame 5 are engaged at the positions of 1b, 103b and 105b, and the fourth group frame 13 is engaged at the inflection point 100b.
The pin 15 is engaged at the position of the inflection point 102b, and the fifth group frame 1
The pin 22 of 9 is engaged at the position of the inflection point 104b.

The pin 50 of the first zoom frame 31 engages at the inflection points 106b and 108b, and the pin 32 of the first zoom frame 31 engages at the inflection point 107b. There is. Further, the pin 27 of the cam frame 24 is engaged at the position of the inflection point 112b.

At this 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 are in the positional relationship as shown in FIG.

When the lens barrel is at the telephoto end of the zoom lens, the three pins 3 of the second group frame 1 are respectively connected to the cam end 101.
The pin 12 of the third group frame 5 is engaged at the position of the cam end 100c, and the pin 15 of the fourth group frame 13 is engaged at the position of the cam end 102c. Frame 19
22 is engaged at the position of the cam end 104c.

The pin 50 of the first zoom frame 31 is engaged at the cam ends 106c and 108c, and the pin 32 of the first zoom frame 31 is engaged at the cam end 107c. Furthermore, the pin 27 of the cam frame 24 is engaged at the position of the cam end 112c.

At this 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 are in the positional relationship as shown in FIG.

Further, when the lens barrel is in the standard zoom state, the three pins 3 of the second group frame 1 have inflection points 101b and cam ends 101c, inflection points 103b and cam ends 103c and The bending point 105b is engaged between the cam end 105c, the pin 12 of the third group frame 5 is engaged between the inflection point 100b and the cam end 100c, and the pin 15 of the fourth group frame 13 is engaged with the inflection point 102b. The fifth group frame 19 is engaged between the cam ends 102c.
22 is engaged between the inflection point 104b and the cam end 104c.

The pin 50 of the first zoom frame 31 has an inflection point 106b, a cam end 106c, and an inflection point 108, respectively.
b between the cam end 108c and the first zoom frame 31
The pin 32 is engaged between the inflection point 107b and the cam end 107c. Further, the pin 27 of the cam frame 24 is engaged between the inflection point 112b and the cam end 112c.

At this 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 are in the positional relationship as shown in FIG.

Next, with reference to FIG. 14, a flow for zooming from the retracted state to the wide side will be described. When you turn on the power switch (not shown) on the camera,
A voltage is applied to the zoom motor 45 to drive it in the clockwise direction (CW direction) (step S1). At this time, the lens barrel is displaced in the wide direction, a signal is output from the photo interrupter (abbreviated as PI in the figure) 239, a timer (not shown) is reset (step S2), and the monitor of the photo interrupter 239 and Monitoring of the output of the photo reflector (abbreviated as PR in the figure) 48 is started.

The output of the photo reflector 48 is high (H).
When it is switched to (step S3), the zoom motor 45 is braked (step S4), and it is confirmed by the output of the photo interrupter 239 that the zoom motor 45 has stopped. At this time, the output counter of the photo interrupter 239 is rewritten to the predetermined "number of switching position pulses W + 1 of the photo reflector 48" (step S5).

Next, a voltage is applied to the zoom motor 45 to drive it counterclockwise (CCW direction) (step S6),
When the fall of the photo interrupter 239 is detected (step S7), the value of the counter of the photo interrupter 239 is decreased by 1 (step S8).

Then, when the counter of the photo interrupter 239 becomes W + α and it is detected that the counter corresponds to the fixed pulse (α) at the wide position (step S).
9) After lowering the drive voltage of the zoom motor 45 (step S10) to slow down the speed of the lens barrel, when it is detected that the counter of the photo interrupter 239 reaches the predetermined value W (step S11), the zoom motor The brake is applied to 45 (step S12), and the lens barrel is stopped at the aimed wide position.

In step S3, when the output of the photo reflector 48 is low (L), the rising edge of the photo interrupter 239 is detected (step S13), and if detected, the timer is reset (step S14). ) Return to step S3. Further, when the predetermined time has elapsed without the rising being detected (step S15), it is determined that the abnormality.

Further, even if the predetermined time elapses without detecting the trailing edge of the photo interrupter 239 in step S7 (step S16), it is determined that the abnormality is still present.

The flow of zooming the lens barrel from the wide side to the tele side will be described with reference to FIG.

When a zoom switch (not shown) provided in 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 tele direction. At this time, the signal of the photo interrupter 239 is output, the timer is reset (step S22), and the monitoring of the photo interrupter 239 and the output of the photo reflector 48 are started.

The output of the photo reflector 48 switches to high (H) in the middle, but at this time, the photo interrupter 2
The output counter of 39 is rewritten to the predetermined "number of switching position pulses W + 1 of the photo reflector 48".

The output of the photo reflector 48 is switched to low (L) near the telephoto (step S23). At this time, the output counter of the photo interrupter 239 is rewritten to a predetermined "switching position pulse number T-1 of the photo reflector 48" (step S24). When it is detected that the counter of the photo interrupter 239 has reached T-α and has reached the position corresponding to the fixed pulse (α) of the tele position (step S25), the drive voltage of the zoom motor 45 is lowered (step S26). ) When it is detected that the counter of the photo interrupter 239 has reached T after the driving speed of the lens barrel is decreased (step S27), the zoom motor 45 is braked (step S28),
Stop the lens barrel at the desired tele position.

In step S23, if the output of the photo reflector 48 is high (H),
The rising edge of the photo interrupter 239 is detected (step S29), and if detected, the timer is reset (step S30) and the process returns to step S23. Further, when the predetermined time has elapsed without the rising being detected (step S31), it is determined to be abnormal.

Referring to FIG. 16, the flow of zooming the lens barrel from the telephoto side to an arbitrary zoom position will be described.

When the 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 this time, the signal of the photo interrupter 239 is output to reset the timer (step S4
2) The monitor of the photo interrupter 239 and the monitor of the output of the photo reflector 48 are started.

When it is detected that the output of the photo reflector 48 is switched to high (H) on the way (step S4).
3), the output counter of the photo interrupter 239 is rewritten to the predetermined "switching position pulse number T-1 of the photo reflector 48" (step S44). After that, when the zoom switch is turned off in the middle (step S45), the zoom motor 45 is braked (step S46) to stop the lens barrel.

If the zoom switch is not turned off during zooming (step S45), the output of the photo reflector 48 is switched to low (L) before wide. At this time, the output counter of the photo interrupter 239 is rewritten to the predetermined number of switching position pulses W + 1 of the photo reflector 48 (step S50).

The counter of the photo interrupter 239 is set to W.
When it becomes + α and it is detected that it is in front of the fixed pulse (α) at the wide position (step S51), the voltage for driving the zoom motor 45 is lowered (step S51).
52), if the counter of the photo interrupter 239 becomes W after the speed of the lens barrel is decreased (step S5).
3) The brake is applied to the zoom motor 45 (step S54) to stop the lens barrel at the intended wide position.

In step S43, if the output of the photo reflector 48 is low (L),
The rising edge of the photo interrupter 239 is detected (step S47), and if detected, the timer is reset (step S48) and the process returns to step S43. Further, if the predetermined time has elapsed without the rising being detected (step S49), it is determined that the abnormality.

The flow when the lens barrel is retracted will be described with reference to FIG. When the power switch is turned off,
A voltage is applied to the zoom motor 45 to drive it counterclockwise (step S61), and the lens barrel starts to be displaced in the retracted direction. At this time, the signal of the photo interrupter 239 is output and the timer is reset (step S6).
2) The monitor of the photo interrupter 239 and the monitor of the output of the photo reflector 48 are started.

The output of the photo reflector 48 is low (L).
(Step S63), the photo interrupter 2
The output counter of 39 is rewritten to the predetermined number of switching position pulses W + 1 of the photo reflector 48 (step S64).

The counter of the photo interrupter 239 is α
Then, when it is detected that the position is equivalent to the fixed pulse (α) at the retracted position (step S65), the drive voltage applied to the zoom motor 45 is lowered (step S6).
6) After slowing down the speed of the lens barrel, if it is detected that the counter of the photo interrupter 239 has reached 0 (step S67), the zoom motor 45 is braked (step S68), and the target retracted position is reached. Stop the lens barrel.

In step S63, if the output of the photo reflector 48 is high (H),
The rising edge of the photo interrupter 239 is detected (step S69), and if detected, the timer is reset (step S70) and the process returns to step S63. Further, when the predetermined time has elapsed without the rise being detected (step S71), it is determined that the abnormality.

As described above, according to such an embodiment, the fixed frame having the inner cam and the lens group holding frame are moved in the optical axis direction while being rotated by the inner cam on the inner peripheral surface side thereof. By providing a cam frame, a pinion gear having an axial length for driving an inner gear of the cam frame, and a key member for restricting rotation of the lens group holding frame, a lens having a large movement amount in the optical axis direction is provided. The lens barrel can be realized with a small number of frame configurations, and therefore, the length of the lens barrel when the lens is retracted can be shortened.

[0111]

As described above, according to the lens barrel of the present invention, a large displacement amount in the optical axis direction can be realized with a small number of frame members.

[Brief description of drawings]

FIG. 1 shows a zoom lens barrel showing an embodiment of the present invention,
The exploded perspective view expanded and shown in the direction of an optical axis.

FIG. 2 is a perspective view showing a configuration in which the lens barrel of the above embodiment is attached to a camera body.

FIG. 3 is a vertical cross-sectional view showing the camera of the above embodiment.

FIG. 4 is an exploded perspective view showing the second group frame, the third group frame, the fourth group frame, and the fifth group frame of the above-mentioned embodiment in an expanded manner in the optical axis direction.

FIG. 5 is an enlarged perspective view showing the lens plate of the above-described embodiment.

FIG. 6 is an exploded perspective view showing the first zoom frame, the screw frame, and the first group frame of the above-mentioned embodiment in an enlarged manner in the optical axis direction.

FIG. 7 is an enlarged perspective view showing details of the lens driving unit of the above embodiment.

FIG. 8 is a development view showing a cam provided on the cam frame of the above embodiment.

FIG. 9 is a development view showing a cam provided on the fixed frame of the above embodiment.

FIG. 10 is a vertical cross-sectional view taken along the optical axis showing the lens barrel in the retracted state of the above embodiment.

FIG. 11 is a vertical cross-sectional view taken along the optical axis showing the lens barrel at the wide-angle end in the embodiment.

FIG. 12 is a vertical cross-sectional view taken along the optical axis showing the lens barrel in the standard state of the above embodiment.

FIG. 13 is a vertical cross-sectional view taken along the optical axis showing the lens barrel at the telephoto end of the above embodiment.

FIG. 14 is a flowchart showing an operation of zooming the lens barrel of the embodiment from the retracted state to the wide position.

FIG. 15 is a flowchart showing an operation when zooming the lens barrel of the above embodiment from the wide side to the tele side.

FIG. 16 is a flowchart showing an operation when zooming the lens barrel of the embodiment from the telephoto side to an arbitrary zoom position.

FIG. 17 is a flowchart showing an operation when retracting the lens barrel of the above embodiment.

[Explanation of symbols]

 1 ... 2 group frame (lens holding frame) 5 ... 3 group frame (lens holding frame) 13 ... 4 group frame (lens holding frame) 19 ... 5 group frame (lens holding frame) 38 ... 1 group frame (lens holding frame) 24 ... Cam frame 25,26 ... Bottomed cam (cam mechanism) 29 ... Internal gear 31 ... First zoom frame 34 ... Fixed frame 40,42 ... Key (key member) 43 ... Pinion gear 45 ... Zoom motor (drive source) ) 46 ... Lens plate

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[Procedure amendment]

[Submission date] February 24, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0020

[Correction method] Change

[Correction content]

In the third group frame 5, substantially cylindrical bearings 7, 8 and 9 having sleeves 6 at both ends are arranged at circumferentially equally divided positions, and the bearing 8 among them has an optical axis. A projecting portion 23 that projects to the rear side in the direction (camera body side) is provided, and the pin 12 that projects in the outer diameter direction is integrally provided on this projecting portion 23. Further, a guide protrusion 10 extending rearward in the optical axis direction is provided on the third group frame 5 at a position between the bearing 7 and the bearing 8 along the circumferential direction, and the guide protrusion 10 is provided between the bearing 8 and the bearing 9. Guide protrusion 1 that extends to the rear side in the optical axis direction
1 is provided.

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Name of item to be corrected] Fig. 14

[Correction method] Change

[Correction content]

FIG. 14

Claims (1)

[Claims] 1. A fixed frame, a plurality of lens groups arranged in the inner circumference of the fixed frame so as to be movable back and forth in the optical axis direction, and a lens holding at least one lens group of the plurality of lens groups. A holding frame, a cam frame that is cam-coupled to the inner circumference of the fixed frame and is moved forward and backward in the optical axis direction by being rotated with respect to the fixed frame, and rotation of the lens holding frame with respect to the fixed frame is restricted. A key member, a cam mechanism provided between the cam frame and the lens holding frame for moving the lens holding frame forward and backward in the optical axis direction by rotating the cam frame with respect to the fixed frame, and an inner circumference of the cam frame. An internal gear provided on the surface, and a pinion gear extending in the optical axis direction for transmitting a driving force from a drive source to the internal gear to rotate the cam frame around the optical axis. A lens barrel characterized by that.