JP2001004897A - Lens-barrel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To retain a moving optical member for image vibration isolation in a lens-barrel at the central position with a simple structure at the off-time of vibration isolation. SOLUTION: In this lens-barrel, a third-group retaining frame 9 retaining a third lens group 1c composing a vibration isolating unit relative to an intermediate lens-barrel 5 is guided rotatably only in the pitch and yaw directions, by being positioned in the optical axis direction and in the rotative direction to the optical axis center by an interfitting relation between a guide pin 11a or the like and a guide part 5a or the like, and the third-group retaining frame 9 has a groove 9a for center retention, and a fourth-group retaining frame 10 retaining a fourth lens group 1d for focusing moving in the optical axis direction is drawn out to the outside of a focusing range, and thereby an engaging pin 10a projecting in parallel with the optical axis is engaged with the groove 9a with the third-group retaining frame 9 positioned on the central position, to thereby execute center retention.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image blur prevention device for suppressing image blur caused by camera shake of a camera, a video camera or the like.

[0002]

2. Description of the Related Art Conventionally, a camera shake or a camera shake is detected by a shake detection sensor such as a vibration gyro.
There is known a system that drives a correction optical system based on the result to suppress image blur on an image forming plane. As this correction optical system, for example, as described in Japanese Patent Application Laid-Open No. 8-248644, a system in which a part of the lens group of the photographing optical system is moved in a plane perpendicular to the optical axis (shift optical system) And the type in which the apex angle of a variangle prism is changed as described in JP-A-5-207358 are the mainstream of the current optical shake correction system. In the cited example, a so-called center holding mechanism that mechanically holds the correction optical system at the center position when not acting as the correction optical system, for example, when the power is off or when the image stabilization is off, etc. It has. By maintaining the center position mechanically, the chromatic aberration and resolution drop are minimized, and the movable frame becomes freely movable when the power is turned off, causing rattling noise, resulting in product value and reliability. Is to prevent the decrease. Maintaining the center when the vibration isolation is off also leads to significant power savings.

[0003]

By the way, the center holding mechanisms described in the above-mentioned conventional examples each have an independent locking mechanism for holding the center, which is disadvantageous in that the number of mechanical parts increases and the cost increases. There is.

An object of the present invention is to provide a lens barrel which eliminates the above-mentioned disadvantages of the prior art and can simplify a mechanism for holding a movable optical member for preventing image blur.

[0005]

In order to achieve the above-mentioned object, the present invention provides a first movable optical member for preventing image blur from being engaged with a second movable optical member which moves in the optical axis direction. The center position is held by the holding mechanism.

[0006]

According to a first aspect of the present invention, there is provided an optical system, comprising: a first movable unit for displacing a predetermined movable range in a direction substantially perpendicular to an optical axis with respect to the optical system to prevent image blur; A movable optical member, a second movable optical member for displacing a part of the optical system in the optical axis direction for focusing or zooming, and the first movable optical member and the second movable optical member. A holding mechanism that engages with each other and holds a position where the optical axis of the first movable optical member substantially coincides with the optical axis of the optical system, so that the first movable member moves to prevent image blur. Since the center of the optical member is held by engagement with the second movable optical member,
The mechanism can be simplified and highly accurate center position information can be obtained. According to a second aspect of the present invention, there is provided an optical system, a first movable optical member for displacing a predetermined movable range in a direction substantially perpendicular to an optical axis with respect to the optical system to prevent image blur, and the optical system. A second movable optical member that displaces a part of the system in the optical axis direction; and a holding member that holds the first movable optical member. The holding member is driven by the second movable optical member. A holding mechanism that engages with the first movable optical member and holds a position where the optical axis of the first movable optical member substantially coincides with the optical axis of the optical system, thereby also preventing image blur. For this purpose, the first movable optical member is moved and held by engagement with the second movable optical member, so that the mechanism can be simplified and highly accurate center position information can be obtained.

According to a third aspect of the present invention, in the lens barrel according to the first aspect, a control system for driving and controlling the plurality of movable optical members is provided, and the holding is performed when power is applied to the control system. By disposing the second movable optical member at a position where the mechanism is released, and disposing the second movable optical member at a position where the holding mechanism operates when the power supply of the control system is turned off, One movable optical member can be reliably held at the center. According to a fourth aspect of the present invention, since the holding mechanism operates when the second movable optical member is out of the movable range at the time of normal imaging, the first optical member can be moved to the first movable optical member if the second movable optical member is not in the imaging possible state. The center of the movable optical member can be reliably held.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a system diagram showing a configuration of a lens barrel for a video camera according to the present embodiment, FIG. 2 is an exploded perspective view of the image stabilizing unit, and FIG. 3 is an explanatory diagram of a center holding mechanism of the image stabilizing unit. In the figure, reference numerals 1a to 1d denote photographing lens groups, which are composed of four groups of convex, concave, convex and convex lenses 1a to 1d, but are not limited to this configuration. In the photographing lens group 1, a lens 1b is a lens group for zooming, and changes the magnification of the photographing subject by moving in the optical axis direction. A lens 1c is a lens group for optical axis deflection. The lens 1d is a lens group having a function of correcting a focus shift generated at the time of focusing and zooming. The lens group having the above configuration is the most popular type of video lens recently. Reference numeral 2 denotes a solid-state imaging device such as a CCD, which is held in a rear lens barrel 6 described later.

Reference numeral 3 denotes a front group lens barrel which holds a first lens group 1a, and a second group holding frame 8 which holds a second lens group 1b is provided at the rear of the first lens group 1a. It is guided by guide bars 7a and 7b in the axial direction and can be moved by a motor (not shown). Reference numeral 4 denotes an aperture unit, which incorporates aperture blades 4a, controls the aperture diameter of the aperture by driving the blades 4a, and adjusts the amount of light applied to the focus surface. Reference numeral 5 denotes an intermediate lens barrel, and a third-group holding frame 9 for holding the third lens group 1c is supported via a so-called anti-vibration unit, which is an optical axis deflection mechanism including mechanical components 11 to 15 and the like. 6
Denotes a rear lens barrel, which is attached to a rear portion of the intermediate lens barrel 5 and has therein a fourth lens group holding frame 1 for holding a fourth lens group 1d.
0 is guided by guide bars 7c and 7d in the optical axis direction and can be moved by a motor (not shown). 4
An engaging pin 10a is provided on the front side of the group holding frame 10 in parallel with the optical axis.
Are integrally protruded, and are engaged with a groove 9a formed in the third-group holding frame 9 when moving forward. The guide bars 7a, 7b and 7c, 7d may be formed by extending one of the guide bars so as to be used for both lens barrels to reduce the number of components. 11 is a guide pin, 12 is a back yoke,
13 is a magnet, 14 is a coil, and 15 is an upper yoke.

Next, the anti-vibration unit will be described in detail with reference to FIG. The third group holding frame 9 has three guide pins 11 on its outer periphery at an interval of about 120 degrees about the optical axis.
a, 11b, and 11c are integrally formed by press-fitting, bonding, or the like, and are fitted into circumferentially long holes 5b formed in guide portions 5a formed in the intermediate barrel 5 so as to protrude in parallel with the optical axis. ing. Further, the intermediate lens barrel 5 and the third group holding frame 9
A guide plate 16 is disposed between the guide plate 16 and two elongated holes 16a and 16b whose center lines are orthogonal to each other, protrude from the intermediate lens barrel 5 and the third group holding frame 9, respectively. (Not shown). With this configuration, the third group holding frame 9 is positioned with respect to the intermediate lens barrel 5 in the optical axis direction and the rotation direction (roll direction) with respect to the optical axis center, and can rotate only in the pitch and yaw directions. Guided by
Although a voice coil motor is used to drive the third lens group 1c in a direction perpendicular to the optical axis, other actuators such as a DC motor such as a pulse motor and a brushless motor and a piezoelectric motor such as an ultrasonic motor are used. It goes without saying that a motor may be used.

Further, the intermediate lens barrel 5 includes the magnets 13a and 13b arranged orthogonally to each other and the back yoke 12 arranged orthogonally to each other and in contact with the magnets 13a and 13b.
a, 12b are fixed, and the upper yoke 15
Is also fixed to the intermediate lens barrel 5 so as to have a certain distance from the magnets 13a and 13b. These may be by adhesion or by magnetic biasing force between the magnets 13a and 13b and the upper yoke 15. The coils 14a and 14b, which are arranged orthogonally to each other, are arranged between them, and are integrally held with the third group holding frame 9. By energizing the coils 14a and 14b thus configured, an electromagnetic force is generated, and a force for moving the third lens group 1c in a direction perpendicular to the optical axis is generated.

Next, the position detector at the time of driving the lens group will be described. Reference numerals 17a and 17b denote magnets contacted by yokes for position detection, arranged perpendicular to each other and magnetized so as to have a magnetic gradient in the driving direction of the third lens group 1c. Reference numerals 18a and 18b denote Hall elements, which are arranged orthogonally to each other with a gap at a position facing the magnets 17a and 17b. Reference numeral 19 denotes a sensor holder which holds the Hall elements 18a and 18b, which itself is held by the intermediate lens barrel 5. This configuration is the same as that described in, for example, JP-A-8-136207. However, the position detection method is not limited to this method. For example, a method in which a slit is provided between PSD and iRED. Needless to say, various methods may be used. The anti-vibration unit configured as described above is disposed between the aperture unit 4 and the rear lens barrel 6.

Next, a system configuration for operating the present embodiment will be described with reference to FIG. Reference numeral 20 denotes an IS microcomputer that drives the image stabilizing system, 21 denotes a driver that drives the coils 14a and 14b of the image stabilizing unit, 22 denotes a signal processing circuit that processes position information from the Hall elements 18a and 18b, and 23 denotes a signal processing circuit. Gyro and other shake detection devices are connected to the IS microcomputer 20 respectively. In the above configuration, the shake signal detected by the shake detection device 23 is I
The signal is input to the S microcomputer 20, the output of the position signal processing circuit 22 is fed back in a direction to cancel the input, and the coils 14 a and 14 b are energized via the driver 21. This constitutes an anti-vibration system, and this anti-vibration system is also arranged in two sets (pitch / yaw) corresponding to the actuator / position / detector.

An AF 24 drives the fourth-group holding frame 10.
A motor 25, a motor driver for the AF motor 24;
A microcomputer 6 controls the motor driver 25.
As is well known, in an AF system (TV-AF) that drives a lens so that the frequency component of the luminance signal of the CCD becomes maximum, the AF motor 24 is driven by a signal of the solid-state imaging device 2. Further, the microcomputer 26 and the IS microcomputer 20 are connected so as to be able to communicate with each other, but it goes without saying that these microcomputers may be one microcomputer.

Reference numeral 27 denotes a power switch of the main body. The microcomputer 26 detects a signal from the power switch and controls the movement of each lens group. That is, when the power is turned on, the fourth lens group 1d acts as a focus / compensation lens, and the third lens group 1c acts as an anti-vibration lens.
When the power-off signal is input, the fourth-group holding frame 10 is moved to the third lens group 1c side before the main power is turned off, and the pins protruding from the fourth-group holding frame 10 in parallel with the optical axis. 1
0 a is engaged with the groove 9 a of the third group holding frame 9. When the main power supply is turned off in this state, the third group holding frame 9 becomes the fourth group holding frame 1
The state is kept at 0. That is, a center holding mechanism of the correction optical system described later is established. The fourth group holding frame 10
Holds the third lens group holding frame 9, the fourth lens group 1d
If is outside the operating range acting as a focus compensating lens, this positioning mechanism will not interfere when the center is released.

The operation of the center holding mechanism of the correction optical system will be described in detail with reference to FIGS. 3, (a) is a front view of the third group holding frame 9, (b) and (c) are enlarged views of a main part explaining the operation, and FIGS. 4 (a) and (b) are flow charts explaining the operation. It is. First, a flow chart when the power is turned on from off in FIG. 4A will be described. In step 1, it is determined whether or not the power switch 27 is pressed and a power-off signal is input to the microcomputer 26. If the power is off, proceed to step 2; if on, return to start.
In Step 2, the coil 14 is controlled via the IS microcomputer 20.
a, 14b is energized, the third-group holding frame 9 is moved to the retracted position shown in FIG. 3B, and the third-group holding frame 9 is positioned at a position that does not interfere with the pins 10a of the fourth-group holding frame 10. Proceed to. In step 3, the fourth group holding frame 10 is driven to move the pin 10 a to a position where it can be engaged with the groove 9 a of the third group holding frame 9, and the process proceeds to step 4. In step 4, the third-group holding frame 9 is moved to the center side, and the third group holding frame 9 is inserted into the groove 9a shown in FIG.
The group holding frame 10 is engaged with the pin 10a. As a result, a center holding mechanism when the power is turned off is established. Also,
It goes without saying that the power-off may be replaced by the vibration-proof off signal.

Next, FIG. 4B is a flowchart when the third group holding frame 9 is temporarily held at the center position when the power is turned on from the off state, and the information is written in an EEPROM (not shown). First, in step 11, it is determined whether or not the power switch 27 is pressed and a power-on signal is input to the microcomputer 26. If the power is on, the process proceeds to step 12, and if the power is off, the process returns to the start. In step 12, the coils 14a and 14b are energized via the IS microcomputer 20 to move the third-group holding frame 9 to the retracted position shown in FIG. 3B, and to a position where it does not interfere with the pins 10a of the fourth-group holding frame 10. The third group holding frame 9 is positioned, and the process proceeds to step S13. In step 13, the fourth group holding frame 10 is driven to move the pin 10a to a position where it can be engaged with the groove 9a of the third group holding frame 9, and
Proceed to 4. In step 14, the third group holding frame 9 is moved to the center side so as to be engaged with the pin 10 a of the fourth group holding frame 10 in the groove 9 a shown in FIG.
In this state, since the lens position can be accurately detected by configuring the pin 10a and the groove 9a with high accuracy or by calibrating at the time of manufacture, it is necessary to write the sensor value in step 14 into an EEPROM (not shown). Can be used to accurately determine the position of the lens. In step 15, the fourth group holding frame 10 is moved to a predetermined position (generally, a focus position), and the processing ends. Thus, a center holding mechanism at the time of power-on is established. Needless to say, the power-on may be replaced with a vibration-proof ON signal.

FIG. 5 shows a second embodiment of the present invention. For the sake of simplicity, the same parts as those in the first embodiment are denoted by the same reference numerals, and only different points will be described. As the center holding mechanism, the pin 10a for holding the third group holding frame 9 in the first embodiment is separate from the fourth group holding frame 10 instead of being formed integrally with the fourth group holding frame 10. That is, an inverted L-shaped lever pin 31 as a holding member is provided between the third group holding frame 9 and the fourth group holding frame 10.
a, and is urged in the counterclockwise direction in the figure by a spring 32.
When the first group 1b is pressed against the front edge of the fourth group holding frame 10, the arm rotates clockwise and the other arm portion 31c is turned into the groove 9a of the third group holding frame 9.
To be engaged. Other configurations are the same as those of the first embodiment.

In this embodiment having the above structure, when the fourth-group holding frame 10 is extended toward the third-group holding frame 9 from the state shown in FIG. 5B, the lever pin 31 is pushed to rotate clockwise around the rotation shaft 31a. 5A, the other arm 31c engages with the groove 9a of the third-group holding frame 9, so that the third-group holding frame 9 can be held. On the other hand, when the fourth group holding frame 10 is retracted rearward from the holding state of FIG. 5A, the lever pin 31 is rotated counterclockwise by the spring 32 to release the third group holding frame 9 as shown in FIG. State.
In this embodiment, for example, if the state shown in FIG. 5A is an optically non-use state and the state shown in FIG. Image deterioration due to the tilting of the group holding frame 10 can be prevented, and the load on the actuator for driving the holding frame satisfactorily can be reduced. The sequence for driving the center holding mechanism is the same as the flow shown in FIG. 4 of the first embodiment.

In this embodiment, as the center holding mechanism,
Although the lever 32 and the spring 32 are used as the holding member, the present invention is not limited to this, and a leaf spring or a tension spring may be used as the spring 32.

[0021]

As described above, according to the first aspect of the present invention, a predetermined movable range is displaced in a direction substantially perpendicular to the optical axis with respect to the optical system in order to prevent image blur. A first movable optical member, a second movable optical member for displacing a part of the optical system in an optical axis direction for focusing or zooming, the first movable optical member, and the second movable member. A holding mechanism for holding the position where the optical member engages with each other and the optical axis of the first movable optical member substantially coincides with the optical axis of the optical system, so that the optical member moves to prevent image blur. Since the movable optical member is held by engagement with another movable optical member, the mechanism can be simplified, and highly accurate center position information can be obtained. According to a second aspect of the present invention, there is provided an optical system, a first movable optical member for displacing a predetermined movable range in a direction substantially perpendicular to an optical axis with respect to the optical system to prevent image blur, and the optical system. A second movable optical member that displaces a part of the system in the optical axis direction; and a holding member that holds the first movable optical member. The holding member is driven by the second movable optical member. A holding mechanism that engages with the first movable optical member and holds a position where the optical axis of the first movable optical member substantially coincides with the optical axis of the optical system, thereby also preventing image blur. For this reason, the movable optical member that moves for this purpose is held by engagement with another movable optical member, so that the mechanism can be simplified and highly accurate center position information can be obtained.

According to a third aspect of the present invention, in the lens barrel according to the first aspect, a control system for driving and controlling the plurality of movable optical members is provided, and the holding is performed when power is applied to the control system. By disposing the second movable optical member at a position where the mechanism is released, and disposing the second movable optical member at a position where the holding mechanism operates when the power supply of the control system is turned off, One movable optical member can be reliably held at the center. According to a fourth aspect of the present invention, since the holding mechanism operates when the second movable optical member is out of the movable range at the time of normal imaging, the first optical member can be moved to the first movable optical member if the second movable optical member is not in the imaging possible state. The center of the movable optical member can be reliably held.

[Brief description of the drawings]

FIG. 1 is a diagram of a lens barrel and an operation system thereof according to a first embodiment of the present invention.

FIG. 2 is an exploded perspective view of the vibration isolation unit.

3A and 3B are explanatory views of the center holding mechanism, wherein FIG. 3A is a front view of a third group holding frame of the vibration isolating unit, FIG. 3B is a state where the vibration isolating unit is used, FIG. Is shown.

FIGS. 4A and 4B are flowcharts for explaining the operation of the center holding mechanism when the power is turned on / off, wherein FIG. 4A shows when the power is off and FIG. 4B shows when the power is on.

FIG. 5 is a sectional view of a lens barrel according to a second embodiment of the present invention;
(A) shows a state where the vibration isolating unit is not used, and (b) shows a state where the vibration isolating unit is used.

[Explanation of symbols]

1a to 1d: photographing lens group, 2: solid-state imaging device, 3
..Front lens barrel, 4..aperture unit, 5..intermediate lens barrel,
6 Rear group barrel, 7a to 7d Guide bar, 8 2
Group holding frame, 9 ... 3 Group holding frame, 9a ... Groove, 10 ... 4
Group holding frame, 10a... Engaging pin, 11a to 11c... Guide pin, 12a, 12b.
13b drive magnet, 14a, 14b coil, 15 upper coil, 16 guide plate, 17a, 17
b. Magnet and yoke for position detection, 18a, 18
b ・ ・ Hall element 、 19 ・ ・ Sensor holder 、 20 ・ ・
IS microcomputer, 21 driver, 22 signal processing circuit, 23 shake detection device, 24 AF motor, 25
Motor driver, 26 microcomputer, 27 power switch, 31 lever pin, 32 spring.

Claims (4)

[Claims] 1. An optical system, a first movable optical member for displacing a predetermined movable range in a direction substantially perpendicular to an optical axis with respect to the optical system to prevent image blur, and for focusing or zooming A second movable optical member for displacing a part of the optical system in the optical axis direction, and the first movable optical member and the second movable optical member are engaged with each other to form the first movable optical member. A lens barrel comprising: a holding mechanism for holding a position where an optical axis of an optical member substantially coincides with an optical axis of the optical system. 2. An optical system, a first movable optical member for displacing a predetermined movable range in a direction substantially perpendicular to an optical axis with respect to the optical system to prevent image blur, and for focusing or zooming. A second movable optical member that displaces a part of the optical system in the optical axis direction; and a holding member that holds the first movable optical member. The holding member is held by the second movable optical member. And a holding mechanism for driving and engaging the first movable optical member and holding a position where the optical axis of the first movable optical member substantially coincides with the optical axis of the optical system. Lens barrel. 3. A control system for driving and controlling the plurality of movable optical members, wherein the second movable optical member is arranged at a position where the holding mechanism is released when power is applied to the control system,
2. The lens barrel according to claim 1, wherein the second movable optical member is disposed at a position where the holding mechanism operates when the power of the control system is turned off. 4. The lens barrel according to claim 1, wherein said holding mechanism operates when said second movable optical member is out of a movable range during normal photographing. .