JP3849111B2 - Camera lens barrel with focus alignment mechanism - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a lens barrel for a camera provided with a focus alignment mechanism capable of performing manual focusing and automatic focusing, and in particular, when a focus ring is rotated during an automatic focusing operation. The lens barrel is configured to stop the automatic focusing operation and manually focus.
[0002]
[Prior art]
A lens barrel for a camera equipped with a focus alignment mechanism capable of performing manual focusing and automatic focusing is not provided with a switching means in addition to one that switches between manual focusing and automatic focusing to perform focusing operation. There is a configuration in which manual focusing and automatic focusing are performed by interposing one differential mechanism.
[0003]
The focus alignment mechanism including the differential mechanism includes a motor drive ring that is driven by a motor and acts as an arm gear, and a planetary gear that is pivotally supported by the drive ring.
[0004]
In the case of automatic focusing, the lens driving ring is rotated in conjunction with the revolution and rotation of the planetary gear by the rotation of the motor driving ring, the lens is moved to the focusing position, and manual focusing is performed. In this case, the driving force of the focus ring is applied to the planetary gear, the lens driving ring is rotated in conjunction with the rotation of the planetary gear, and the lens is moved to the in-focus position.
[0005]
Therefore, such a focus matching mechanism using a differential mechanism is connected to the planetary gear because the motor interlocking system and the focus ring interlocking system are connected to each other during the automatic focusing of the motor drive. The motor driving force transmitted to the planetary gear is transmitted to the focus ring in addition to the lens driving ring.
[0006]
For this reason, in order to prevent the focus ring from rotating during the automatic focusing operation, a friction mechanism is provided in the focus ring and its interlocking gear train.
[0007]
That is, friction that overcomes the interlocking force applied to the focusing ring from the planetary gear during the automatic focusing operation is given to the focusing ring so that the focusing ring is not rotated during the automatic focusing operation.
[0008]
[Problems to be solved by the invention]
In the above-described focus alignment mechanism, the lens drive ring is rotated by the automatic focusing operation, and when the lens drive ring hits the stopper at the infinite position (∞ position) or the closest position, the lens drive ring cannot be rotated. Most of the transmitted motor driving force is applied to the focus ring, and therefore the focus ring rotates as the planetary gear rotates.
[0009]
In order to solve this problem, the position of the lens drive ring is shifted so that the rotation amount of the lens drive ring is larger than the original stopper position that stops the rotation of the lens drive ring at the infinite position and the close position. A configuration means is adopted in which the rotation of the infinite position or the closest position is electrically detected, the automatic focusing motor is stopped and controlled according to the detection before the ring hits the stopper, and the focus ring is not rotated. ing.
[0010]
However, even if such a configuration means can prevent the focusing ring from rotating due to automatic focusing, the stopper ring position of the lens driving ring is not close to the original infinite position. When operating and focusing, the infinite position and the closest position of the lens drive ring cannot be determined.
[0011]
That is, there is a problem that it is difficult to set the lens position to the infinite position or the closest position in manual focusing by the focusing ring turning operation.
[0012]
On the other hand, when the focus ring is inadvertently operated while the motor is in autofocus operation, it is detected that the hand touches the focus ring, and the motor is operated in response to this detection signal. There has been proposed a lens barrel that is configured to stop and end the automatic focusing operation.
[0013]
However, this lens barrel is extremely inconvenient for holding the camera because it cannot touch the focus ring of the lens barrel when holding the camera for automatic focusing. .
For this reason, the focus ring is made small so that the hand cannot be touched. However, with this configuration, it is difficult to operate the focus ring when manually operating the focus ring and performing manual focusing. It will be a thing.
[0014]
A stopper that mechanically stops the rotation of the lens drive ring at an infinite position and a close position of the lens; a focus interlocking ring that rotates integrally with the focus ring; and the focus fixed to interlocking rings, diene was provided along its ring - provided da substrate and the barrel fixing frame, the diene tip side spring force - has a contact terminal which is brought into contact with da substrate, the diene - with giving constantly load Kasuringu, the follower - - the follower by the contact force of the contact terminals abuts the da substrate and detection switch for detecting from da substrate and the contact terminal, - the rotation of the dregs interlocking rings diene When the focus ring is rotated by receiving the output of the differential mechanism as the rotation of the lens driving ring by the automatic focusing operation is stopped by the stopper. Has a configuration in which a control means for stopping an automatic focusing operation in response to the detection signal of the detection switch.
[0015]
[Means for Solving the Problems]
In order to achieve the above-described object, the present invention provides a lens in conjunction with a lens drive ring that rotates in response to an output of a differential mechanism that connects a focus ring drive system and a motor drive system. The present invention relates to a camera lens barrel that includes a moving focus matching mechanism and performs manual focusing for focusing operation and automatic focusing by motor driving via the differential mechanism.
[0016]
A stopper that mechanically stops the rotation of the lens driving ring at the infinite position and the closest position of the lens;
A focus interlocking ring that rotates integrally with the focus ring;
An encoder substrate fixed to the focus interlocking ring along the ring and a lens barrel fixing frame; and a contact terminal abutted against the encoder substrate by a spring force, the encoder substrate A detection switch that constantly applies a load to the focus ring by the contact force of the contact terminal that contacts the substrate, and detects rotation of the focus interlocking ring;
When the focus ring is rotated by receiving the output of the differential mechanism as the rotation of the lens drive ring by the automatic focusing operation is stopped by the stopper, the detection switch detects Control means for stopping the automatic focusing operation in response to the signal is provided.
[0017]
[Action]
In the lens barrel of the present invention, if the focus ring rotates during the automatic focusing operation, the control means that responds to the detection signal of the detection switch stops the automatic focusing operation.
[0018]
Therefore, for example, when the lens driving ring hits the stopper at the infinite focusing position or the closest focusing position by the automatic focusing operation, and the focusing ring rotates, the control means that responds to the detection signal is immediately automatically focused. In order to stop the focusing operation, the focus ring rotates slightly and stops.
[0019]
If the focus ring rotates during the automatic focusing operation, the automatic focusing operation is stopped, and then manual focusing becomes possible.
For this reason, there is no problem in camera holding and focusing operations.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
1 is a side view of the lens barrel shown by cutting the upper half portion, FIG. 2 is a side view of the lens barrel shown by cutting the lower half portion, and FIG. 3 is an AA line in FIG. FIG. 4 is a cross-sectional view, and FIG. 4 is a plan view of the lens barrel shown with the second fixed frame removed.
[0021]
In these drawings, 11 is a first fixed frame, 12 is a second fixed frame which is an outer frame of the first fixed frame, and 13 and 14 are non-rotating with respect to the first fixed frame 11 in the optical axis direction. It is a moving frame that moves.
The movable frames 13 and 14 are integrally fixed, and the movable lens 13 supports the front lens 15 and the movable frame 14 supports the rear lens 16.
[0022]
The first fixed frame 11 has a reduced diameter frame portion on the rear side (right side in FIGS. 1 and 2), and a female screw type helicoid ring 17 is rotatable in the frame portion and moved in the optical axis direction. The female screw of the helicoid ring 17 is meshed with the helicoid screw (male screw) of the moving frame 14.
[0023]
As shown in FIGS. 1 and 3, the helicoid ring 17 has a recessed groove 18 formed in a rearward direction in a part thereof, and is rotated by an interlocking lever 19 in which a tip portion is inserted into the recessed groove 18. .
The interlocking lever 19 is fixed to the rear end surface of the lens driving ring 20 and turns according to the rotation of the lens driving ring 20.
[0024]
The interlocking lever 19 has a turning range defined by the window hole 21 of the first fixed frame 11.
That is, the interlocking lever 19 is swung at the front end side within the window hole 21 and is brought into contact with the hole edge of the window hole 21 in the direction around the optical axis to determine the swivel range. (See Figs. 1 and 4)
[0025]
Specifically, when the lens driving ring 20 is rotated until the interlocking lever 19 comes into contact with one hole edge (hole edge in the direction around the optical axis) of the window hole 21, the lenses 15, 16 are in an infinite focus position. When the lens driving ring 20 is rotated until the interlocking lever 20 hits the other hole edge, the lenses 15 and 16 are moved to the closest focusing position.
Thus, the hole edge of the window hole 21 serves as a stopper that restricts the rotation of the lens drive ring 20.
[0026]
On the other hand, a motor drive ring 22 is rotatably provided on the rear side of the first fixed frame 11.
The motor drive ring 22 has an internal gear formed on the inner peripheral surface thereof, and an interlocking gear 23 (see FIG. 2) meshes with the internal gear.
[0027]
That is, the interlocking gear 23 is driven and rotated by a motor (not shown) to rotate the motor drive ring 22.
The interlocking gear 23 is an elongated gear elongated in the direction of the optical axis. This is because the motor drive system attached to the moving frame 13 is moved while being connected to the interlocking gear 23.
[0028]
Further, a planetary gear 24 that rotates by the rotation of the ring is rotatably mounted on the motor drive ring 22. Reference numeral 25 denotes a support ring for the planetary gear 24.
This planetary gear 24 is a small gear having a large and small diameter gear portion, the large diameter gear portion meshes with the internal gear of the focus interlocking ring 26, and the small diameter gear portion is an internal gear of the lens drive ring 20 described above. Meshed.
An internal gear is formed on the inner peripheral surface of the focus interlocking ring 26.
[0029]
The planetary gear 24 constitutes a differential mechanism that receives a motor driving force and a manual operating force from the focus ring 27. In this embodiment, as shown in FIG. Three planetary gears 24 are provided at equal positions.
However, the number of the planetary gears 24 can be increased or decreased.
[0030]
Further, the focus interlocking ring 26 is fixed integrally with the focus ring 27, and is rotated by a rotation operation of the focus ring 27, and the planetary gear 24 is rotationally driven by the internal gear.
[0031]
The second fixed frame 12 is integrally fixed to the first fixed frame 11, and is provided with a diaphragm ring 28, an electric terminal ring 29, and a bayonet ring 30.
[0032]
On the other hand, the lens barrel configured as described above includes a detection switch 31 that detects the rotation of the focus ring 27.
The detection switch 31 includes contact terminals 32 a, 32 b and 32 c attached to the first fixed frame 11 and an encoder board 33 provided on the focus interlocking ring 26.
[0033]
FIG. 5 is a partially cutaway plan view showing the detection switch 31 in an enlarged manner, and FIG. 6 is an operation explanatory view of the detection switch 31.
As can be seen from FIG. 5, a terminal base 34 having contact terminals 32a, 32b, and 32c is fixed to the first fixed frame 11, and each contact terminal is in contact with the encoder board 33 by a spring force.
The terminal base 34 is disposed in the cutout hole 35 of the first fixed frame 11.
[0034]
Specifically, the contact terminals 32a, 32b, and 32c receive a projecting force by the coil springs 36a, 36b, and 36c, and the tips of these terminals are in contact with the plate surface of the encoder board 33.
The contact terminal 32c is an earth terminal, and the contact terminals 32a and 32b are in contact with the code plate portion 33a.
The encoder substrate 33 is provided on the entire circumference of the tip surface of the focus interlocking ring 26.
[0035]
In addition, the detection switch 31 of the present embodiment is provided with two contact terminals 32a and 32b that are brought into contact with the code plate portion 33a to output a detection signal as a two-phase pulse in order to prevent a switch chattering problem. It is as.
However, the present invention can be implemented by providing any one of the contact terminals 32a and 32b.
[0036]
In addition, the lens barrel described above detects the lens position of the focusing operation by the brush terminal 37 provided in the interlocking lever 19 and the sliding plate 38 provided on the second fixed frame 12, as shown in FIG.
Note that the brush terminal 39 and the sliding plate 40 shown in FIG. 2 detect the aperture value.
[0037]
In the lens barrel of the present embodiment, the motor for automatic focusing is driven to rotate according to the distance measurement signal, whereby the interlocking gear 23 rotates in conjunction with the motor driving ring 22.
As a result, the planetary gear 24 revolves while rotating to rotate the lens drive ring 20.
[0038]
When the lens driving ring 20 is rotated, the interlocking lever 19 is rotated, the helicoid ring 17 is rotated, and the moving frames 13 and 14 are fed out by helicoid screw feeding.
By this operation, the lenses 15 and 16 move in the optical axis direction, and automatic focusing is performed.
[0039]
Mode - While data is driven automatic focusing operation as described above is performed, follower - but subjected to motor driving force, follower - - Kas interlocking ring 26 mode by rotation and revolution of the planetary gears 24 Kas interlocking ring 26 arc - contact terminals 32a to de substrate 33, 32 b, because the contact with 32c spring force, follower has become integral with the ring 26 - rotational load of the Kasuringu 27 in the rotational load of the lens driving ring 20 compared to thoroughly rather large, the follower - Kas interlocking ring 26 does not rotate.
In other words, the focus ring 27 does not rotate when the automatic focusing operation is performed between the infinite position and the closest position.
[0040]
Further, as the lens drive ring 20 rotates, the interlocking lever 19 comes into contact with the hole edge on one side of the window hole 21, and the lenses 15 and 16 move to an infinite focus position, or the interlocking lever 19 When the lenses 15 and 16 are brought into contact with the closest focusing position by contacting the other edge of the window hole 21, the hole edge of the window hole 21 serves as a stopper and stops the rotation of the lens driving ring 20.
[0041]
Therefore, the motor driving force transmitted to the focus interlocking ring 26 via the planetary gear 24 is increased by the subsequent motor rotation. Therefore, the focus interlocking ring 26 rotates. At first, the rotation is immediately detected by the detection switch 31.
[0042]
Thus, the control circuit that responds to the detection signal of the detection switch 31 stops the motor drive at the initial stage of the rotation of the focus interlocking ring 26.
As a result, even when the lens drive ring 20 is stopped by the stopper, the focus ring 27 stops rotating slightly.
[0043]
When the focusing ring 27 is rotated while the automatic focusing operation is performed between the infinite position and the closest position, the detection switch 31 detects this rotation and responds to the detection signal. The control circuit stops motor driving.
In this case, the focus ring 27 can be rotated and manually focused.
[0044]
In the manual focusing operation, the focus ring 27 is rotated and the focus interlocking ring 26 is rotated.
When the focus interlocking ring 26 is rotated, the planetary gear 24 is rotated by the internal gear, and the lens driving ring 20 is rotated.
[0045]
As a result, the interlocking lever 19 turns and the helicoid ring 17 turns.
As a result, the lenses 15 and 16 are moved in the optical axis direction by helicoid screw feed of the moving frames 13 and 14 to manually focus.
[0046]
In the lens barrel configured as described above, when the lens driving ring 20 hits the stopper by the automatic focusing operation and the motor driving is stopped, the focusing ring 27 is not activated during the automatic focusing operation. The determination that the motor drive is stopped after being prepared can be made based on the output signal of the detection device (brush terminal 37, sliding plate 38) that detects the rotation of the lens drive ring 20.
[0047]
In addition, by detecting the rotation position of the lens drive ring 20 and changing the number of pulses for determining the rotation of the focus ring 27, detection when the focus ring 27 is inadvertently rotated during the automatic focusing operation is detected. Can have a time lag.
[0049]
The present invention also provides a lens barrel provided with a focus alignment mechanism that moves and focuses either the front lens 15 or the rear lens 16 or a lens that extends a lens by a cam cylinder instead of a helicoid screw. The same can be applied to the lens barrel.
[0050]
Further, a focusing motor can be provided in the camera body, and the motor driving ring 22 can be rotated by connecting the motor and the lens barrel with a coupling.
[0051]
【The invention's effect】
As described above, according to the lens barrel of the present invention, when the focus ring rotates in a relationship where the rotation of the lens drive ring is stopped by the stopper by the automatic focusing operation, the detection signal of the detection switch is output. The responding control means immediately stops the automatic focusing operation.
As a result, there is no problem that the focus ring rotates during automatic focusing.
[0052]
In addition, if the lens ring is inadvertently rotated during the automatic focusing operation, the automatic focusing operation stops immediately, so that the automatic focusing due to the rotation of the focusing ring is stopped. There is less error in focus.
[0053]
Further, when manual focusing is performed by rotating the focus ring, the infinite position and the closest position are optically accurately determined.
Further, the lens barrel of the present invention can normally hold the camera even during the automatic focusing operation, so that the lens barrel is excellent in camera operability.
[Brief description of the drawings]
FIG. 1 is a side view of a lens barrel showing an embodiment of the present invention, with an upper half portion cut away.
FIG. 2 is a side view of the lens barrel shown with a lower half portion cut away.
3 is a cross-sectional view taken along line AA in FIG.
FIG. 4 is a plan view of the lens barrel with the second fixed frame removed.
FIG. 5 is an enlarged plan view of a detection switch provided in the lens barrel.
FIG. 6 is an operation explanatory diagram of the detection switch.
[Explanation of symbols]
11 First fixed frames 13 and 14 Moving frame 15 Front lens 16 Rear lens 17 Helicoid ring 19 Interlocking lever
20 Lens Drive Ring 21 Window Hole 22 Forming Stopper 22 Motor Drive Ring 23 Interlocking Gear 24 Planetary Gear 26 Focus Interlocking Ring 27 Focus Ring 31 Detection Switch 32a, 32b, 32c Contact Terminal 33 Encoder Board

Claims (1)

A focusing mechanism that moves a lens in conjunction with a lens driving ring that rotates in response to an output of a differential mechanism that connects a focusing ring driving system and a motor driving system; In a lens barrel for a camera that performs manual focusing for focusing operation and automatic focusing by motor driving,
A stopper that mechanically stops the rotation of the lens driving ring at an infinite position and a close position of the lens;
A focus interlocking ring that rotates integrally with the focus ring;
Said follower - fixed to Kas interlocking rings, diene was provided along its ring - provided Da substrate and the barrel fixing frame, said distal side by a spring force ene - have a contact terminal which is brought into contact with da substrate and, wherein the diene - with giving constantly load Kasuringu, the follower - - the follower by the contact force of the contact terminals abuts da substrate wherein the rotation of the dregs interlocking ring ene - detecting than da substrate and the contact terminal A detection switch;
When the focus ring is rotated by receiving the output of the differential mechanism as the rotation of the lens drive ring by the automatic focusing operation is stopped by the stopper, the detection switch detects A lens barrel for a camera provided with a focus matching mechanism, characterized in that control means for stopping an automatic focusing operation in response to a signal is provided.

Images