JP2556060B2 - Zoom lens - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a lens that can be electrically driven and manually driven and can be zoomed.

(Prior Art) Japanese Patent Application No. Sho 61 proposed by the applicant of the present invention as a photographing lens capable of moving an optical system by electric drive and manual drive.
-106083, and in this publication, a means for synthesizing the displacement position of the lens for automatic focusing and the displacement amount of the lens for manual focusing is provided in the projection lens, whereby the moving speed of the lens during automatic focusing is provided. There was an effect such as increasing the number by the manual focusing operation ring.

A differential gear mechanism, that is, a mechanism mainly composed of a planetary gear that can rotate and revolve around the optical axis of the photographing optical system, is used as a means for synthesizing the displacement amount.

(Problems to be Solved by the Invention) However, in the above disclosed technique, only the displacement amount of the lens at the time of focusing is taken into consideration, and the variable power operation (zooming) is structurally disclosed. Has not been done.

On the other hand, conventionally, a so-called one-hand zoom in which a focusing operation is performed by rotating a manual operation ring around an optical axis and a zooming operation is performed by driving the manual operation ring in the optical axis direction A mechanism called a mechanism is well known, but this mechanism is provided with a means for synthesizing the displacement amount of the lens during manual focusing and the displacement amount of the lens during automatic focusing such as a differential gear mechanism. not exist.

Therefore, in constructing a lens including the differential gear mechanism and the one-hand zoom mechanism, when the operation associated with one of the manual focusing operation and the manual zooming operation is associated with the other manual operation. A mechanism that does not affect the operation must be provided.

It is an object of the present invention to provide a zoom lens that can obtain the above mechanism with a simple configuration.

(Means for Solving Problems) In order to solve the above problems, in the present invention, the focusing optical system (L1), the zooming optical system (L2, L3), the manual focusing operation and the manual zooming are performed. Manual operation means (25) that can be operated respectively,
The electric drive means (37) driven by the driving force of the motor, the manual operation means to which the manual focusing operation is applied, and the electric drive means are driven respectively, and when one of the both means operates, output is performed accordingly. Is generated, and when both are operating, a differential gear train (20
a, 19a, 19b, 13a) and a focusing drive system (11c, 13, 13c, for receiving the output of the differential gear train and driving the focusing optical system).
47) and a variable power drive system (2) for driving the variable power optical system in response to the manual operation means to which the manual variable power operation is applied.
5 and 48), the differential gear train is a planetary gear (19a, 19b) capable of rotating and revolving around the optical axes of both optical systems, and extending in parallel with the optical axis. Also, an engaging portion (50) that engages with the rotation shaft (19c) of the planetary gear, the manual operation means, and the rotation shaft.
In response to the manual focusing operation of the manual operation means, the engagement portion rotates the rotation shaft along a circumference centered on the optical axis to rotate the planetary gear about its own axis. Revolving, whereby the differential gear train drives the focusing drive system, and in response to the manual zooming operation of the manual operating means, the engaging portion slides along the rotary shaft, Thus, the focusing drive system is not driven, but only the variable power drive system is driven.

(Operation) According to the zoom lens of the present invention, when the manual operation means is operated by one of the focusing operation and the zooming operation,
A mechanism that does not affect the operation associated with the other operation can be obtained with a simple configuration.

(Embodiment) FIGS. 1 and 2 show an embodiment of the present invention, which is applied to a zoom lens barrel for automatic focusing capable of automatic focusing and manual focusing based on the drawings. Will be explained.

The zoom lens barrel shown in FIG. 1 can be attached to the camera B having the automatic focus detection device shown in FIG. 2, and during automatic focusing photography, the driving force of the automatic focusing motor 113 on the camera side is used for focusing. The optical system L1 is configured to be driven.

In FIG. 1, a fixed barrel 11 having a bayonet claw 11a for mounting on a camera body is composed of an inner barrel portion 11f and an outer barrel portion 11g, and the focusing optical system is provided on the inner circumference of the inner barrel portion 11f. L1
(Focusing optical system), L2, L3 (variable magnification optical system), L4 (master optical system) are held. On the outer circumference of the inner cylinder portion 11f, a cam cylinder 13 having an external gear 13a which constitutes a part of a differential gear mechanism, which will be described in detail later, and a manual operation (focusing and zooming)
The member 25 is rotatably fitted.

In the cam groove 13c provided in the cam barrel 13, the straight-moving barrel 15
A sliding pin 47 planted in is engaged with a straight groove 11c provided in the inner cylinder portion 11f of the fixed cylinder 11 and extending in the optical axis direction. Therefore, the rotation of the cam barrel 13 causes the rectilinear barrel 15 to move,
It moves along the optical axis together with the focusing optical system L1. A focusing operation is performed by moving the straight-moving barrel 15 and the focusing optical system L1 in the optical axis direction.

At the front part of the cam barrel 13, there is a distance scale display portion 13b, which can be read through a distance display window 11b provided in the fixed barrel 11.

The rotation moving cylinder 25b of the manual operation member 25 is fitted to the outer periphery of the inner cylinder portion 11f of the fixed cylinder 11. The manual operation member 25 is composed of an operation unit 25a which is externally operated. A peripheral groove 25c is formed inside the rotary moving cylinder 25b, and the peripheral groove 25c is engaged with the pin 48.

The pin 48 is embedded in the holding tube 16 of the variable power optical system L2.
Further, the pin 48 is a linear guide groove 17a of the cam barrel 11d of the inner cylindrical portion 11f and the holding barrel 17 of the variable magnification optical system L2 fitted inside the inner cylindrical portion 11f.
Is also engaged. A pin 49 implanted in the holding cylinder 17 of the variable power optical system L3 is engaged with the cam groove 11e of the inner cylinder portion 11f.

Therefore, even if the manual operation member 25 rotates about the optical axis, the peripheral groove 25c and the pin 48 only idle, so that the variable power optical system L
2, L3 never drive.

On the other hand, when the manual operation member 25 moves in the optical axis direction, the circumferential groove
A holding cylinder 16 integrated with a pin 48 that engages with 25c and the cam groove 11d,
The variable power optical system L2 is driven in the optical axis direction while rotating. At this time, the rotation of the variable power optical system L2 is changed by the straight groove 17a of the holding barrel 17.
And the second group pin 48 engaging with the third group holding cylinder 17
Rotates integrally with the second group holding cylinder 16, and at the same time, the third group holding cylinder
The pin 49 and the cam groove 11e of the fixed barrel 11 implanted in the holding barrel 17 move the holding barrel 17 in the optical axis direction to perform a displacement operation (zooming).

The operation section 25a operated externally of the operation member 25 is an operation section 25c.
It is sandwiched with the fixed portion 11 via an elastic member 40 integrated with
A predetermined torque is applied to the manual operation member 25 by the frictional force. The operating member 25 has an engaging portion 5 for supporting the shafts 19c of the planetary gears 19a and 19b forming part of a differential gear mechanism described later.
0 is engaged. Planetary gears 19a, 19b integral with the shaft are provided at both ends of the shaft 19c, and the gear 19a is the external gear 1 described above.
It meshes with 3a. Therefore, when the operation member 25 is rotated around the optical axis, the shaft 19c is integrally rotated with the operation member 25, and the operation member 25 moves in the optical axis direction (variable magnification operation).
The shaft 19c does not interlock with the operating member 25.

On the inner periphery of the outer peripheral portion 11g of the fixed cylinder 11, the first internal gear 20a meshing with the planetary gear 19b and the coupling shaft 37 which is rotated by the motor driving force (driving force of the motor 113 in FIG. 2).
An internal gear cylinder 20 integrally provided with a second internal gear 20b that meshes with a pinion gear 37b formed at one end of the internal gear barrel 20 is rotatably supported.

A rotary plate 51 is rotatably supported on the inner periphery of the outer peripheral portion 11g, and the shaft 19c of the planetary gear described above rotates integrally in the rotation direction and restricts movement in the optical axis direction. It has become.

Furthermore, a photointerrupter 53 is fixed inside the outer peripheral portion 11g. This photointerrupter 53
A code plate 51a (having light-transmitting holes provided at regular intervals in the circumferential direction) provided on the rotary plate 51 between the light emitting portion and the light receiving portion rotates as the teaching operation member 25 rotates. By moving, a pulse signal corresponding to the rotation of the manual operation member 25 is transmitted to the in-lens CPU 29. Encoder 55 on fixed cylinder 11
Has been fixed.

The encoder 55 outputs a code corresponding to the position of the sliding brush 57, that is, the rotational angle position of the cam cylinder 13 by sliding the surface of the sliding brush 57 fixed to the tip of the cam cylinder 13. Conductor pattern is formed. That is, a signal indicating whether the focusing optical systems L1 and L2 are at the infinity position, the close-up position, or another position is transmitted to the in-lens CPU 29.

The CPU 29 in the lens is connected to the lens mount contact pin 31 via the leaf spring 33, and the contact pin 31 and the leaf spring 33.
Are held inside the mount inner diameter by the contact housing 35.

The clamp screw 45, which is screwed into the fixed barrel 11, presses the outer periphery of the inner gear barrel 20 by screwing the clamp screw 45 into the inner gear barrel 20.
It is configured to be able to prevent the rotation of the.

In the zoom lens having the above-described configuration, in the manual focusing operation, the engaging portion 50 moves the rotating shaft 19c in response to the rotation of the manual rotating barrel 25 to the optical axes of the focusing optical system L1 and the variable power optical systems L2 and L3. The planetary gears 19a and 19b are rotated and revolved around a circle centered on the center of the differential gear train 20a, 19a, 19b, 1
3a rotates the cam barrel 13 by an amount corresponding to the operation amount of the manual operation barrel 25, and the engagement between the cam groove 13c and the pin 47 causes the focusing optical system L to move.
Drive 1

In the manual zooming operation, the engagement portion 50 slides along the rotary shaft 19c in response to the movement of the manual rotary barrel 25 in the optical axis direction, and the cam groove 11d is driven without driving the focusing optical system L1. By engaging with the pin 48, only the variable power optical systems L2 and L3 are driven.

FIG. 2 shows the lens barrel A of this embodiment as a camera body B.
FIG. 2 is a schematic diagram schematically showing the system configuration in the state of being attached to the. The same parts as those in FIG. 1 are designated by the same reference numerals.

In FIG. 2, when the taking lens A is mounted on the lens mount 141 on the camera body B side through the bayonet claw 11a provided on the fixed barrel 11, the lens side coupling shaft 37 is coupled with the camera body side coupling shaft 125. To do. The coupling shaft 125 is rotationally driven by a motor 113 controlled by a drive signal from a CPU (arithmetic processing unit) 111 in the body via a friction clutch 115 and reduction gear trains 121 and 123.

The light from the subject that has passed through the focusing optical system L1 is partially reflected by the movable mirror 129 and forms a subject image on the focusing screen 133. The subject image is observed through the condenser lens 134, the pentaprism 135, and the viewfinder eyepiece lens 136.

Part of the light transmitted through the semi-transparent mirror portion provided in the central portion of the movable mirror 129 is reflected by the sub mirror 131 and received by a pair of light receiving devices (pupil split type automatic focus detection device) 127 including an imaging lens. Form an image on the surface. The signal photoelectrically converted by the light receiving device 127 is sent to the in-body CPU 111, and the defocus amount (the amount and direction of image plane deviation from the planned focal plane) is obtained according to the image formation state.

The in-body CPU 111 is electrically connected to the in-lens CPU 29 via the lens contacts 33, 31 and the body-side contact 139, and various information regarding the lens is stored in the in-lens CPU 29 inside the R 29.
Can be read from OM. Therefore, the information indicating the image plane movement amount per coupling unit rotation amount is read out, and the motor drive amount necessary for focusing is obtained from the defocus amount described above. When the motor drive is started, the code plate 119 and the photo interrupter 117 provided on the motor shaft generate a pulse signal according to the motor shaft rotation amount. Therefore, when a pulse corresponding to the required motor rotation amount is generated. Stop the motor drive and focus.

Motor 11 controlled according to the image formation state of focusing optical system L1
When the lens side drive shaft 37 is rotated by the drive of 3, the pinion gear 37b integrated with the drive shaft 37 is rotated. The rotation of the pinion gear 37b is transmitted to the internal gear cylinder 20 via the second internal gear 20b of the internal gear cylinder 20, and the first internal gear 20a rotates about the optical axis. By the rotation of the first internal gear 20a, the planetary gear 1
9a and 19b rotate. For automatic focusing only, planet gear 19
The shaft 19c supporting the a and 19b and the manual rotary cylinder 25 are elastic members 4
Since the rotation is suppressed by the frictional force of 0, the rotation of the planetary gear 19a causes the cam cylinder 13 having the external gear 13a meshing with the planetary gear 19a to rotate.

Therefore, the rotational torque T1 of the manual rotary cylinder 25 and the rotary torque T2 of the cam cylinder 13 need to be set to a relationship of T1> T2.

The operation of the differential gear mechanism during the automatic focusing operation will be described below.

In the case of automatic focusing from a long distance to a close distance, the cam cylinder 13 is rotated in the counterclockwise direction by the internal gear cylinder 20 to rotate the cam cylinder 13 to the external gear 13a
And rotate clockwise. The sliding pin 47 engaged with the cam groove 13b by the rotation of the cam barrel 13 is guided by the straight-movement guide groove 11c and moves leftward in FIG. 1 to move the straight-movement barrel 15 and the focusing optical system L1 to the left. Displace toward. As a result, focus adjustment is automatically performed from infinity to a close range.

On the contrary, in the case of automatic focusing from the closest distance to the far distance, the internal gear 20a rotates clockwise due to the reverse rotation of the pinion gear 37b, and the cam barrel 13 rotates counterclockwise together with the external gear 13a. As a result, the rectilinear barrel 15 and the focusing optical system L1 move to the right, and automatic focusing to a long distance is performed.

Next, the operation of the differential gear mechanism when the manual focusing operation is performed during the automatic focusing operation will be described.

When a manual focusing operation is performed during the automatic focusing operation by the above motor drive, the rotation of the internal gear cylinder 20 and the rotation of the planetary gears 19a, 19b by the motor drive, and the revolution of the planetary gears 19a, 19b by the manual focusing operation. And are combined to rotate the cam barrel 13 (that is, drive amount combining means).

As another configuration of the drive amount synthesizing means, there is a case in which only one of the drive of the cam barrel 13 by the motor drive and the drive of the cam barrel 13 by the manual operation is selectively operated. For example, when the contrast of the subject becomes low during the automatic focusing operation, or when the subject suddenly moves and the defocus amount increases, the defocus amount may not be obtained even if focus detection is performed. . In such a case, it is necessary to manually perform the focusing operation. That is, the manual focusing operation is performed during the automatic focusing drive in the state where the defocus amount is not obtained, but during the manual operation, the drive motor 113 is irrelevant to the photographer's intention (for example, the automatic focusing operation is performed). If it responds, it will not be possible to perform manual operation as expected, which is inconvenient.
Also, when manual focusing operation is performed during automatic focusing drive with the defocus amount obtained, the actual movement amount of the focusing optical system L1 is the combined amount of the motor drive amount and the manual operation drive amount. Therefore, the relationship between the number of pulses of the photo interrupter 117 and the amount of movement of the focusing optical system L1, that is, the amount of movement of the image plane (the amount of movement on the focus plane) is broken, and accurate focusing becomes impossible. .

Therefore, in this embodiment, the photointerrupter 53 detects that the manual rotary cylinder 25 has been operated, and the automatic focusing drive of the photographing lens is stopped. That is, when the manual rotary cylinder 25 is operated, the rotary plate 51 also rotates integrally.
A pulse signal is transmitted from the photo interrupter 53 to the in-lens CPU 29 according to the rotation. CPU29 in this lens
The photo interrupter 53 has a fixed number Δn within a fixed time Δt.
When the above pulses are generated, it is determined that the manual focusing operation is being performed, and a signal for stopping the motor drive (hereinafter, referred to as a servo prohibition flag) is transmitted to the in-body CPU 111. If the values of the time Δt and the number of pulses Δn are extremely small, the motor 113 will stop even if the manual rotation barrel 25 makes a slight movement. Therefore, when holding the lens barrel, the hand operation ring 25 is touched by the hand. This must be avoided, and the holdability of the lens barrel will deteriorate. Further, if the value is extremely large, accurate focusing cannot be performed as described above, so that the value needs to be an appropriate size.

As described above, when the manual focus operation is performed during the automatic focus drive, the servo inhibit flag is continuously output while the manual operation ring 25 is rotating, that is, while the manual operation ring 25 is being manually operated, and the drive motor 113 Stop driving. The manual focusing operation is completed,
When the rotation of the manual operation ring 25 is stopped, the servo prohibit flag is switched so as not to be output, and the motorized automatic focusing operation is restarted. However, if the motor drive is started at the same time when the rotation of the manual operation ring 25 is stopped, the movement of the manual operation ring 25 cannot be stopped even for a moment during the manual operation. Therefore, it is necessary to set the timing for stopping the output of the servo prohibition flag after a fixed time Δt ′ from the rotation of the manual operation ring 25 stopping. The value of Δt ′ may be fixed to a fixed value, but the optimum value of Δt ′ is taken according to the type of lens, size, and photographing conditions. Therefore, the value of Δt ′ may be arbitrarily changed by the photographer using the changeover switch. Also, CPU1 on the body side
In the program of 11, the motor drive may be restarted after a fixed time Δt ′ from the time when the servo prohibit flag from the lens is not present.

When the automatic focusing lens barrel of this embodiment is attached to a camera body that is not for automatic focusing or is attached to a camera body for automatic focusing shown in FIG. 2, the coupling shaft 125 is retracted (passive). When the focusing mode is selected), the lens side coupling shaft 37 is free. When the manual operation ring 25 is rotated for manual focusing operation in this state, the cam barrel
Since the rotation torque of the internal gear cylinder 20 is generally smaller than the rotation torque of 13, the cam cylinder 13 does not rotate because only the internal gear cylinder 20 rotates, and the optical system L1 does not move. I cannot operate the focus.

Therefore, in the present embodiment, the rotation of the gear cylinder 20 is restricted by screwing the clamp screw 45 during the manual focusing operation, and the rotation of the manual rotation cylinder 25 is transmitted to the cam cylinder 13 to enable the manual operation.

It is also possible to provide a switch interlocking with the screwing of the clamp screw 45 and send a signal from the lens to the body to indicate that manual operation is being performed when the switch is clamped.

The present embodiment has been described above with reference to FIGS. 1 and 2, but the present invention is not limited to this embodiment. For example, the distance scale display is performed by providing the distance scale portion 13b interlocked with the cam cylinder 13, but by increasing the number of positions that can be detected by the encoder 55, the output code of the encoder 55 causes the rotational position of the cam cylinder 13 to be You can know the shooting distance. Therefore, it is possible to display the value on the lens side or the body side using a liquid crystal display element or the like.

Further, in the present embodiment, a problem in the case where the drive amount synthesizing means synthesizes the drive by the automatic focusing operation and the drive by the manual focusing operation is described, and an example (the manual operation ring 25
The driving of the motor 113 is stopped when is operated), but it is not always necessary to stop the driving of the motor even if the respective drivings are combined. For example, when the manual operation ring 25 is manually operated, the operation amount and direction are electrically detected, and the number of output pulses of the photo interrupter 53 in the body is corrected based on the operation amount to adjust the focusing optics. system
If the correlation between the amount of movement of L1 and the output pulse of the photo interrupter 53 in the body can be maintained, accurate automatic focusing drive can be achieved without stopping the motor drive during manual operation.

Further, according to the present embodiment, when the manual operation ring is operated, when the output signal of the photointerrupter or the like, which electrically detects the motor drive amount by the operation amount, is corrected, It is not always necessary to stop the motor drive during manual operation. In this case, it is possible to add a manually operated drive amount to the motor drive amount, and it is possible to increase the moving speed of the moving optical system.

Also, if the coupling shaft is fixed to the camera body for automatic focusing, if automatic focusing is impossible, or if automatic focusing is uncertain, a manual operation member may be used even during automatic focusing drive. It is possible to quickly operate near the focal point simply by rotating 25, and if the rotation of the manual operation member 25 is stopped, it will automatically return to the automatic focusing drive and can be automatically driven to the focal point. There is an effect that the focusing operation can be performed.

(Effects of the Invention) As described above, according to the present invention, when the operation associated with one of the focusing operation and the scaling operation of the manual operating means is performed, the operation associated with the other operation is influenced. No mechanism can be obtained with a simple structure.

[Brief description of drawings]

FIG. 1 is a sectional view of an operation zoom lens having a differential gear mechanism according to an embodiment of the present invention, which is capable of automatic focusing and manual focusing, and FIG. 2 is a camera body for automatically focusing the zoom lens. A schematic view of the system configuration when the device is mounted on the is shown. (Explanation of symbols of main parts) 13,19,20 …… Differential gear mechanism 55,57 …… Movement end detecting means 45 …… Clamp screw 25 …… Manual operation ring 40 …… Frictional braking elastic member 51a …… Code plate (manual operation detection means) 53 …… Photo interrupter (manual operation detection means) 45 …… Clamp screw

Claims (3)

(57) [Claims] 1. A focusing optical system, a variable power optical system, a manual operation means capable of a manual focusing operation and a manual variable power operation, an electric means driven by a driving force of a motor, and the manual operation. Following the respective manual operation means and the electric means to which the focusing operation is applied, when one of both means operates, an output corresponding to that is generated, and when both operate, an output obtained by combining both operations is output. A differential gear train that is generated, a focusing drive system that drives the focusing optical system by receiving the output of the differential gear train, and the manual operation means that has been subjected to the manual zooming operation. A variable-magnification drive system that drives a variable-magnification optical system, wherein the differential gear train is a planetary gear that is capable of rotation and revolution about the optical axes of both optical systems; A rotation shaft of the planetary gear, which extends to the And an engaging portion that engages with, and in response to the manual focusing operation of the manual operating means, the engaging portion rotates the rotating shaft along a circumference around the optical axis. Then, the planetary gear is rotated and revolved, whereby the differential gear train drives the focusing drive system, and in response to the manual zooming operation of the manual operating means, the engaging portion rotates the rotation. A zoom lens characterized in that it slides along an axis, and thereby drives only the variable power drive system without driving the focusing drive system. 2. The differential gear train is provided on a first gear that rotates by the electric drive means and on a circumference around the optical axes of the both optical systems, and is rotatable about the optical axes. A second gear with which the first gear meshes, and a second gear that is provided on the circumference around the optical axis, is rotatable about the optical axis, and meshes with the planetary gear Includes three gears, the planetary gear, while meshing with the second gear and the third gear, performs the revolution and the revolution about the optical axis, the focusing drive system, The zoom lens according to claim 1, wherein the focusing optical system is driven in response to the third gear. 3. A relationship between a rotational torque T1 for operating only the manual operation means and a load torque T2 for moving the focusing optical system satisfies T1> T2. The zoom lens according to claim (1).