JP3188733B2 - Image stabilizer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical device such as a camera.
Image blur to correct image blur caused by camera shake etc.
The present invention relates to a correction device .

[0002]

2. Description of the Related Art Conventionally, various devices for correcting camera shake have been proposed. As an example, a so-called variable apex angle prism is used in which a transparent liquid is sealed between two parallel flat glass plates to change the relative angle between the two glass plates, thereby generating a prism effect and polarizing light rays. It has been proposed in JP-A-2-59718. This is to add the variable apex angle prism to the photographing optical system and eliminate the image blur on the image forming surface due to the shake of the imaging optical system by the light beam deflecting action of the variable apex angle prism.

In general, the variable apex angle prism is disposed in front of the photographing optical system. In this case, the coefficient of the prism drive angle with respect to the amount of blur of the photographing optical system is constant regardless of the characteristics of the photographing optical system. is there. That is, even if the photographing optical system is a zoom lens, it is not necessary to change the control constant for image blur correction. However, in this method, it is necessary to increase the effective aperture of the variable apex angle prism, so that there is a disadvantage that the apparatus becomes large.

[0004] The applicant of the present invention solves this problem by displacing a part of the optical system in the photographing optical system in the direction perpendicular to the optical axis, thereby moving the image on the image plane and eliminating image blurring. It is proposed in, for example, Japanese Patent Laid-Open No. 62-44707. FIG. 13 shows the principle of this blur correction.

In FIG. 13, reference numeral 1 denotes a photographing optical system including a variable power system, a focus adjustment system, and a correction optical system, and 2 denotes a correction optical system for performing blur correction. When the correction optical system is displaced by d _L , The image is displaced by d _IM . Reference numeral 3 denotes an angular displacement meter, and an imaging optical system 1
Is detected and output. 4 is the shake angle displacement θ
Is a coefficient converter for converting into a displacement signal d necessary for eliminating image blur.

Reference numeral 5 denotes an actuator, which drives and controls the correction optical system 2 in accordance with the displacement signal d. Numeral 6 denotes a position detection sensor for detecting the actual displacement d _L of the correction optical system 2. The signal from the sensor 6 is fed back to the input system of the actuator 5 through an operational amplifier 7 so that the correction optical system The system 2 can accurately follow the displacement signal d.

Here, the relationship between the shake angle displacement θ of the photographing optical system 1, the displacement d _L of the correction optical system 2, and the image movement (displacement) d _IM will be described.

Assuming that the focal length of the photographing optical system 1 is f and the photographing magnification is β, the photographing optical system 1 has θ [rad around the front principal point.
Image displacement amount d _IM when produced an angular blur] is _{............... d IM = f (1 +} β) · θ. On the other hand, if the ratio of the image displacement d _{IM to} the displacement d _L of the correction optical system 2 is referred to as eccentric sensitivity S _d , then d _IM = S _d · d _L. Since the eccentric sensitivity S _d is a function of the focal length f and the imaging magnification β, it can be expressed as S _d = S _d (f, β). The principle of the image blur correction is that the image blur (expression) due to the angular blur of the photographing optical system 1 is eliminated by the image displacement (expression) due to the lens displacement, so that d = d _L = (d _{IM / S d) = {f} · (1 + β) · θ} / {S d (f, β)} = kθ ............... or _{θ = {S d (f,} β) · d L} / {f・ (1 + β)｝ = d _L / k is derived.

[0009]

However, the above-mentioned prior art has the following problems.

That is, “f”, “(1 + β)”, “S _d (f, f)” is obtained by zooming or focusing.
β) changes, but the maximum displacement d _L max of the correction optical system 2 does not change. Then, from the equation, the shake correction possible angle θmax changes depending on the focal length f. In general, the eccentric sensitivity S _d (f, β) due to zooming
Becomes larger on the telephoto side, but smaller than the rate of change of the focal length f, so that the shake correction possible angle θmax becomes larger on the wide side than on the telephoto side. This is shown in FIG.

In this case, the following problems occur.

1) When a camera with a zoom lens is set up, the amplitude of the camera shake of a person is almost constant regardless of the focal length. On the other hand, the shake correction possible range must be larger than the normal camera shake amplitude. However, if it is too large, the photographer may feel uncomfortable at the time of the panning operation or may be difficult to use.

2) A large blur correction range on the wide side means that aberrations of the optical system also increase on the wide side. On the other hand, since the image blur displacement amount per unit blur angle is small on the wide side, image deterioration due to camera shake is smaller than on the tele side. Nevertheless, if the photographer performs a panning operation even on the wide side, the image blur correction device may use the maximum region of the blur correction range in response to the panning operation. If exposure is performed at this time, image degradation due to aberration occurs even if camera shake correction can be performed accurately.

An object of the present invention is to provide an apparatus
To correct image shake and image shake caused by the shake.
The relationship between the amount of operation of the image blur correction means and the focal length
The image stabilizer that changes according to the position of the adjustment group
In each setting state of the variable power optical group or the focus adjustment group.
So that the maximum amount of shake that can be corrected is set appropriately.
As a result, the operating range of the image blur correcting means may cause large aberrations.
To prevent it from being included
In each setting state of the zoom optical group or focus adjustment group,
Improved operability and improved usability of the device
It is an object of the present invention to provide an image blur correction device capable of performing the image blur correction.

[0015]

In order to achieve the above object, the present invention is directed to an image blur correction device used with an imaging optical system having at least a variable power optical group or a focus adjustment group, comprising: Means, an output of a shake detecting means for detecting a shake of the apparatus, and a zoom position of the zoom optical group.
Changes depending on the data to be converted or the position of the focus adjustment group
Depending on the data, and a signal forming means for forming a drive signal for operating the image blur correction means, and drive means for driving the image blur correcting means on the basis of a driving signal of the signal formation means, said Changes according to the zoom position of the zoom optical group
Data that changes depending on the position of the focus adjustment group.
The image blur correction means by the driving means based on data
Maximum allowable drive range form the maximum allowable drive range signal
Generating means, the maximum allowable driving range signal and the driving signal,
Comparing means for comparing
Depending on the position of the variable power optical unit or the position of the focusing unit.
Image blur correction within the maximum allowable driving range
Drive for controlling the driving means so that the means is driven
Motion control means, and a zoom position of the zoom optical group,
Is determined by the image blur correction means for the position of the focus adjustment group.
The change in the maximum blur correction angle is the maximum of the image blur correction means.
Compared to the case where the allowable driving range is fixed, it is eased.
This is an image blur correction device.

[0016]

[0017]

1 to 5 are diagrams according to a first embodiment of the present invention.

FIG. 2 shows an image forming optical system used in the present invention. The focal length is three times as large as 100 mm to 300 mm. Tele end (f
= 300 mm).

This imaging optical system is composed of four groups, and in zooming, the fourth group is fixed, and the first, second and third groups move.
Also, the first lens unit moves during focus adjustment. Then, by displacing the second lens unit in a direction perpendicular to the optical axis, the image on the imaging plane is displaced to perform image blur correction.

Various characteristics relating to image blur correction of the image forming optical system are as shown in FIG.

When the subject distance is infinite, the eccentricity sensitivity S _d (f, β) at f = 100 mm and 300 mm is “2.
5 "and" 3.5 "(see FIG. 14). On the other hand, the maximum displacement d _L max of the correction optical system (second group) is determined by the structure of the support mechanism of the optical system, and is “± 2 mm” regardless of the focal length f. Then, the maximum displacement d _IM max of the image
Are respectively "± 5 mm" and "± 7 mm" according to the above equations.
0 rad "and" ± 0.023 rad ". In other words, it can be seen that the shake correction possible amount can be corrected for a shake angle that is twice or more on the wide side as compared with the tele side when the shake angle is compared.

Therefore, the gist of the present invention is to appropriately adjust the amount of shake correction possible.

FIG. 1 is a block diagram showing a main part according to a first embodiment of the present invention.

In FIG. 1, CMR is a camera body, and LNS is an interchangeable lens that can be attached to and detached from the camera body CMR.

First, the configuration of the camera body CMR will be described.

The CCPU is a microcomputer in the camera (hereinafter referred to as a microcomputer), and is a one-chip microcomputer having a ROM, a RAM, and an A / D conversion function. The microcomputer CCPU in the camera performs a series of operations of the camera, such as automatic exposure control, automatic focus adjustment, and film winding, according to a camera sequence program stored in the ROM. For this purpose, the microcomputer CCPU in the camera communicates with peripheral circuits and lenses in the camera body CMR to control the operation of each circuit and lens.

LCM is a lens communication buffer circuit,
Power is supplied to the lens LNS via the power supply line VL, and output from the camera body CMR to the lens LNS via the signal line DCL and from the lens LNS to the camera body C
It serves as an inter-lens communication buffer for output via the signal line DLC to the MR.

SNS is a focus detection line sensor (hereinafter simply referred to as a sensor) composed of a CCD or the like, and SDR is a drive circuit for driving the sensor SNS in accordance with a command from a microcomputer CCPU in the camera. An image signal is taken in, amplified, and sent to the microcomputer CCPU in the camera.

The light from the lens LNS is the main mirror M
The light enters the photometric sensor SPC via the M, the focus glass PG, and the pentaprism PP, and its output signal is input to the microcomputer CCPU in the camera and used for automatic exposure control (AE) according to a predetermined program.

Reference numeral DDR denotes a switch detection and display circuit, which switches the display of the camera display member DSP based on data sent from the microcomputer CCPU in the camera and turns on various operation members (SWMD) of the camera. Notify the off state to the microcomputer CCPU in the camera by communication.

SW1 and SW2 are switches linked to a release button (not shown). The switch SW1 is turned on when the release button is pressed in the first stage, and the switch SW2 is turned on when the release button is pressed down to the second stage. . As will be described later, the microcomputer CCPU in the camera generates a start signal for photometry, automatic focus adjustment operation, and image blur correction operation when the switch SW1 is turned on, and performs exposure control and film winding with the switch SW2 turned on as a trigger. The switch SW2 is connected to the "interrupt input terminal" of the microcomputer CCPU in the camera. Even during execution of the program when the switch SW1 is turned on, an interrupt is generated by turning on the switch SW2, and the process can immediately proceed to a predetermined interrupt program.

MTR1 is a film feeder for film feeding, and MTR2 is a motor for mirror up / down and shutter spring charging.
The driving circuits MDR1 and MDR2 control forward / reverse rotation.

MG1 and MG2 denote magnets for starting the movement of the first and second curtains of the shutter, respectively.
Power is supplied to R2, and the microcomputer CCPU in the camera controls the shutter STR.

Next, the configuration of the lens LNS will be described.

The LCPU is a microcomputer in the lens, and is a one-chip microcomputer having a ROM, a RAM, and an A / D conversion function like the microcomputer CCPU in the camera. Signal line DCL lens microcomputer LCPU from the camera body C M R
Lens F according to the command sent through
LNS drive control and aperture drive control are performed. In addition, various operating conditions of the lens (how much the focus adjusting optical system has been driven, how many stops have been stopped, and the like) and parameters (open F number, focal length, coefficient of defocus amount vs. feed amount, etc.) ) Is transmitted to the camera via the signal line DLC.

Reference numeral FMTR denotes a motor for driving the focus adjusting lens FLNS, which rotates a helicoid ring (not shown) via a gear train to move the lens FLNS forward and backward in the optical axis direction to perform focus adjustment.

FDR is a drive circuit of the above-mentioned motor FMTR, which is driven by a signal from a microcomputer LCPU in the lens.
It controls the forward / reverse rotation of the motor FMTR, braking, and the like.

This embodiment shows an example of the front lens focus type. When a focus adjustment command is sent from the camera body CMR, the motor is controlled in accordance with the driving amount and direction sent at the same time. By driving the FMTR, the focus adjustment lens FLNS is moved in the optical axis direction to perform focus adjustment.
The movement amount of the focus adjusting lens FLNS is monitored by a pulse signal of an encoder circuit ENCF and counted by a counter in a microcomputer LCPU in the lens. When the predetermined movement is completed, the motor FMTR is reset. Control.

For this reason, once the focus adjustment command is sent from the camera body CMR, the microcomputer CCPU
Does not need to be involved in driving the lens at all until the driving of the lens is completed. Further, the content of the counter can be transmitted to the camera body CMR as needed.

ENCB is an encoder for detecting the absolute position of the focusing lens FLNS, and ENCZ is an encoder for detecting the zoom position, both of which are code patterns provided on a helicoid ring and a zoom ring. And a signal detected by a known method such as a brush and a detection brush is sent to the microcomputer LCPU in the lens.

When an aperture control command is sent from the camera body CMR, a stepping motor D known for driving an aperture is used in accordance with the number of aperture stages sent simultaneously.
Drive MTR.

The ICPU is an image blur correction microcomputer, which controls the image blur correction operation and transmits a signal from the camera body CMR to the lens LNS.
And the signal DLC from the lens LNS to the camera body CMR, and the output signal from the microcomputer ICPU is input to the microcomputer LCPU in the lens. That is, communication with the microcomputer CCPU in the camera is performed only with the microcomputer LCPU in the lens, and the microcomputer IC for image blur correction is used.
The PU takes a form of intercepting the communication between the two. The communication from the image blur correction microcomputer ICPU to the camera microcomputer CCPU is performed by the lens microcomputer LCPU.
Done through.

AD is an angular displacement meter for detecting a shake of the lens LNS. For example, Japanese Patent Application No. Hei.
No. 2011183 uses a sensor that utilizes the inertia of the fluid in a cylindrical case. The angular displacement output θ of the angular displacement meter is transmitted to the image blur correction microcomputer ICPU. Control signals SAD1 and SAD2 for controlling the response frequency characteristics of the angular displacement meter are sent from the image blur correction microcomputer ICPU.

Reference numeral ICNT denotes an image blur correction control circuit which will be described later. The circuit has a filter, an amplifier, a switch, etc., and drives and controls an image blur correction actuator IACT which will be described later. It has a signal input and output line.

ILNS is a correction optical system which is an optical axis decentering means, is supported by a guide mechanism described later, and can move in parallel to a plane perpendicular to the optical axis.

IACT is an actuator for image blur correction provided in the support mechanism and is constituted by a magnetic circuit formed by permanent magnets and a coil moving in the magnetic circuit, and displaces the correction optical system ILNS. .

PSD is a position detection sensor for detecting the position of the correction optical system ILNS, and an infrared light emitting diode IRE.
When the light from D passes through the slit SLT that moves integrally with the correction optical system ILNS and enters the light receiving surface of the position detection sensor PSD, the position detection sensor PSD receives the position of the incident light, that is, the position of the correction optical system ILNS. Position signal (displacement d
_L ). The position signal (d _L ) is supplied to the image blur correction microcomputer ICPU and the image blur correction control circuit ICN.
Input to T.

SWIS is an image blur correction system main switch. When the switch SWIS is turned on, power is supplied to the image blur correction microcomputer ICPU and its peripheral circuits, and the image blur correction control circuit ICNT starts operating. When the switch SW1 of the camera body CMR is turned on, this signal is transmitted to the image blur correction microcomputer ICPU via the lens microcomputer LCPU, and the image blur correction actuator
Over data IACT is an image blur correction operation is started by driving
You .

Next, the angular displacement meter AD, which is a detection sensor, will be described with reference to FIGS.

The basic configuration of the angular displacement meter AD is almost the same as that proposed by the present applicant in Japanese Patent Application No. 2-201183. Here, the control circuit is slightly modified and a simplified circuit is used. Will be explained.

First, the mechanical components will be described.

The inside of the cylindrical outer cylinder 21 is filled with a liquid, and the floating body 22 is supported in the liquid so as to be freely rotatable about a bearing 27. A light projecting element 25 and a light receiving element 26 for optically detecting the movement of the floating body 22 are arranged as shown in FIG.
2 and a yoke 23 forming a closed magnetic circuit, and this yoke 23
A winding coil 24 is arranged between the part and the floating body 22.

Next, the electrical components will be described.

A portion A surrounded by a dotted line is a position detecting portion for detecting the position of the floating body 22 with respect to the outer cylinder 21, and reflects the infrared light emitted from the light projecting element 25 on the floating body 22. This is a basic configuration in which light is detected by the light-receiving element for position detection 26.
As is known, the photocurrents Ia and Ib generated by the light receiving element 26 are divided according to the position of the center of gravity of the infrared light incident on the light receiving element 26, differentially amplified by the operational amplifier 28, and the angular displacement of the floating body 22, that is, the lens mirror. The displacement (θ) of the displacement of the cylinder is output.

A portion B surrounded by a dotted line is a control section for changing the parameters of the sensor. In the figure, two switches SWAD1, SWAD2 on switches on-off controlled by the image blur correcting Mycobacterium <br/> down ICPU the control line SAD1, SAD2, the switch when the line becomes high level is on (closed) Becomes When the switch is off (open), the angular displacement output θ is amplified by the operational amplifier 29 at an amplification factor of “R ₃ / R ₀ ”.
When the switch is turned on, the resistor R ₁ or the resistor R ₂ is connected in parallel to the resistor R ₀ , and as a result, the combined resistance is reduced, so that the amplification factor is increased. Then, for example, "R ₀ = R ₁ = R ₃ =
When 2R ₂ ", the amplification factor of the operational amplifier 29 by on-off of the switch is set as in FIG. 3 (b).

The part C surrounded by the dotted line is the winding coil 2
4 is a driver section for driving the operational amplifier 4, and the operational amplifier 30 serves as a buffer. Therefore, a current corresponding to the output voltage of the control unit B flows through the winding coil 24. That is, the floating body 2 2
Flows through the coil a current proportional to the angular displacement (theta) of floating body 2 2 is given a restoring force proportional to the angular displacement (theta), and the restoring force can be switched by the size of the switch SWAD1, SWAD2 . Then, as the restoring force increases, the angular displacement output θ quickly converges to “0”, and the high-pass characteristics are strong as the sensor characteristics, that is, the low-frequency blur detection ability decreases.

The escape from the saturated region of the angular displacement output θ saturated during panning is quickened.

The rise time of the sensor when the power is turned on is reduced. And so on.

Although FIG. 1 shows the image blur correcting mechanism for only one axis, camera shake occurs in two-dimensional directions (up, down, left, and right). The ILNS must also work in two dimensions.

FIG. 4 shows the support mechanism of the correction optical system ILNS in detail. This correction optical mechanism operates the correction lens 41 corresponding to the correction optical system ILNS in FIG. 1 in a direction that corrects camera shake in a plane orthogonal to the optical axis, thereby obtaining an image blur suppression effect on an image forming plane. It is.

The correction lens 41 can be driven freely in two directions perpendicular to the optical axis and at right angles to each other (pitch 42p and yaw 42y). The configuration is shown below.

In FIG. 4, a fixed frame 43 for holding the correction lens 41 is provided with a sliding bearing 44 such as polyacetal resin (hereinafter referred to as POM) fixed to the arm-shaped projections 43a and 43b.
It is possible to slide on the pitch slide shaft 45p via p. The pitch slide shaft 45p is
Is attached to the projection 46a. Further, a pitch coil 48p is attached to the fixed frame 43. Pitch coil 4
8p is pitch magnet 49p and pitch yoke 410p
The fixed frame 43 is driven in the pitch direction 42p by passing an electric current. A slit 411p is provided in the pitch coil 48p,
The position of the fixed frame 43 in the pitch direction 42p is detected based on the relationship between the light emitter 412p (infrared light emitting diode IRED) and the light receiver 413p (semiconductor position detecting element PSD).

The above is the driving mechanism in the pitch direction.

Next, a driving mechanism in the yaw direction (the direction of the arrow 42 y ) will be described.

The protrusions 46b and 46c on the holding frame 46 have P
A sliding bearing 44y such as OM is mounted. On the other hand, a yaw slide shaft 45y is fixedly provided on the projection 414a on the housing 414 attached to a lens barrel (not shown). Since the bearing 44y can slide on the shaft 45y, the holding frame 46 and the fixed frame 43 can also move in the yaw direction (the direction of the arrow 42y). The fixed frame 43 is provided with a yaw coil 48y, and a yaw magnet 49y sandwiching the yaw coil.
The fixed frame 43 is also driven in the yaw direction 42y due to the interaction between the magnetic field and the magnetic field formed by the yoke yoke 410y. A slit 411y is provided in the yaw coil 48y, and detects the position of the fixed frame 23 in the yaw direction 42y as in the pitch direction. The driving of the correction lens 41 in the pitch direction 42p and the yaw direction 42y is configured as shown in FIG.

The position of the flat portion 43c provided at the lower left portion of the fixed frame 43 is regulated in the optical axis direction by a blur prevention projection 50 provided on a lens barrel fixing portion (not shown). This is because the position restricting portion of the fixed frame 43 is 43a, 43b in the pitch direction and 46b, 46 in the yaw direction in the above-described configuration.
c and two positions, respectively, because at least three position restricting portions (holding portions) are required to restrict the operation of the fixed frame 43 only in the shift direction. Therefore, two protrusions 50
(One back side is not shown) regulates the position of the flat portion 43c from the front and back, and prevents the fixed frame 43 from moving (deflecting) in the optical axis direction.

In the above configuration, the correction lens 41 can be driven independently in the pitch direction and the yaw direction.

Next, a drive circuit of the above-described correction optical support mechanism will be described.

FIG. 5 shows the image blur correction control section in detail. A portion surrounded by a dotted line corresponds to the image blur correction control circuit ICNT in FIG. The circuit ICNT, the angular displacement meter AD, and the like are provided two each for driving in the pitch and yaw directions, and p is included in the name of each element and signal line for the pitch direction, and p is used for the yaw direction. Has a subscript y added.
However, in the following description, the pitch and yaw directions are collectively described, and the suffixes p and y are omitted.

AD is the above-mentioned angular displacement meter, which outputs the angular displacement (θ) of the lens barrel. SAD1 and SAD2 are control lines for changing the blur detection characteristics of the above-described angular displacement meter AD. When the lines SAD1 and SAD2 become high level, the AD high-pass characteristics of the angular displacement meter are strengthened and the detection capability for low-frequency blur is improved. It is configured to decrease. That is, when the angular displacement output θ is saturated by an operation such as panning, the lines SAD1 and SAD2 are appropriately set to a high level, whereby the return of the angular displacement output θ to “0” is expedited.

The angular displacement output θ is calculated by the microcomputer ICP for blur correction.
The coefficient is converted into a control signal d in U, and is input to the sample hold circuit SH in the image blur correction control circuit ICNT. The sample hold circuit SH is controlled by a control line SSH from the microcomputer ICPU for shake correction. When the line SSH is at a low level, the control signal d is applied to the circuit SH.
, And when the line SSH is at the high level, the control signal d at the time of the high level is held and outputted.

SWACT is a switch for controlling ON / OFF of a control signal input to the actuator IACT. The switch SWACT is controlled by a blur correction microcomputer ICPU.
When the CT is turned on, the driving of the actuator IACT is started, and the blur correction operation is started.

COMPE is a phase compensation circuit for increasing the stability of the feedback loop system.
_ACT is the voltage applied to the actuator IACT.

When the actuator IACT operates, the correction optical system ILNS is driven, and the slit SLT moving integrally with the optical system ILNS and the IR fixed to the lens barrel are operated.
By the action of ED and PSD, the displacement signal d _L of the correction optical system ILNS is output from PSD. Then, the signal d _L
Is inverted at the addition point P1 to form a feedback loop with d as a control amount, and the correction optical system I
The LNS is driven and controlled by a displacement corresponding to the control signal d.

Next, the camera body CMR having the above configuration
The operation of each of the lens and the lens LNS will be described with reference to FIGS.

First, the operation of the camera body CMR will be described with reference to the flowchart of FIG.

When a power switch (not shown) on the camera body CMR side is turned on, power supply to the microcomputer CCPU in the camera is started, and the operation from step (002) is started through step (001).

In step (002), the state of the switch SW1 which is turned on by pressing the release button in the first stage is detected. When the switch SW1 is turned off, the flow shifts to step (003) to store the RAM in the microcomputer CCPU in the camera. Clears and initializes all set control flags and variables,
Proceed to step (004).

In step (004), a command to stop the image blur correction operation (IS) is transmitted to the lens LNS side.

The above steps (002) to (004) are performed by the switch S
It is repeatedly executed until W1 is turned on or the power switch is turned off.

When the switch SW1 is turned on, the flow shifts from step (002) to (011).

In step (011), lens communication is performed.
This communication is communication for obtaining information necessary for performing exposure control (AE) and focus adjustment control (AF). When the microcomputer CCPU in the camera sends a communication command to the microcomputer LCPU in the lens via the signal line DCL. The microcomputer LCPU in the lens transmits information such as the focal length, the AF sensitivity, and the open F number stored in the ROM via the signal line DLC.

In step (012), a command to start the image blur correction operation is transmitted to the lens LNS side.

In step (013), a "photometry" subroutine for exposure control is executed. That is, the microcomputer CCPU in the camera inputs the output of the photometric sensor SPC shown in FIG. 1 to the analog input terminal, performs A / D conversion, and obtains the digital photometric value Bv.

At step (014), an "exposure calculation" subroutine for obtaining an exposure control value is executed. The subroutine
In the chin, the apex operation expression “Av + Tv = Bv + S
v "and a predetermined program diagram, the shutter value Tv
And the aperture value Av, and store them at a predetermined address in the RAM.

At step (015), the "image signal input" subroutine is executed. Here, the camera microcomputer CCP
U inputs an image signal from the focus detection sensor SNS.

In step (016), the defocus amount of the photographing lens is calculated based on the input image signal.

The subroutine flow of the above steps (015) and (016) is disclosed by the present applicant in Japanese Patent Application No. 61-16082.
No. 4, etc., and a detailed description thereof will be omitted here.

In step (017), a "lens drive" subroutine is executed. In the subroutine, the camera body C
The number of drive pulses of the focusing lens FLNS calculated in step (016) on the MR side is calculated by the microcomputer LCPU in the lens.
Only to the microcomputer LCPU
Drives and controls the motor FMTR according to a predetermined acceleration / deceleration curve. Then, after the driving is completed, an end signal is transmitted to the microcomputer CCPU in the camera, the subroutine ends, and the process returns to step (002) again.

Next, the above step (015) surrounded by a broken line
A case where a release interrupt due to the turning on of the switch SW2 during execution of each operation in the focus adjustment cycle shown in (017) will be described.

As described above, the switch SW2 is connected to the interrupt input terminal of the microcomputer CCPU in the camera, and when the switch SW2 is turned on, the interrupt function immediately proceeds to step (021) even if any step is being executed. It is configured to migrate.

When the switch SW2 interrupt is input during execution of the step enclosed by the broken line, the flow shifts to step (022) via step (021).

In step (022), a release operation is performed.

In step (023), the film is wound up to complete the shooting of one frame, and the process returns to step (002).

The subroutines of steps (013) to (017) and steps (022) and (023) are already known, and detailed description thereof will be omitted.

Next, an image blur correction operation performed on the lens LNS side using the flowchart of FIG. 7 will be described. In each step, the addition of the subscript py indicates that the operations in the pitch and yaw directions are performed sequentially.

In step (101), when the main switch SWIS for image blur correction is turned on, power is supplied to the microcomputer ICPU for image blur correction, its peripheral circuits, the angular displacement meter AD, and the like. Thereby, the microcomputer ICPU for image blur correction
Begins execution of the subsequent program steps in FIG. 7 (102).

In step (102), all flags and all variables in the image blur correction microcomputer ICPU are cleared and set to "0". In step (103), control lines SAD1 _py ,
SAD2 _{py is set} to a high level to give a strong high-pass characteristic to the angular displacement output θ _py of the angular displacement meter AD _{py so that} the displacement of the correction optical system ILNS starts from a state close to the origin when image blur correction is started. In step (104), the control line SSH _{py is set} to the low level to permit the passage of the control displacement d _py .

In step (105), image blur correction (IS)
The start command is determined, and when the IS start command has not been received from the camera body CMR, the process proceeds to step (106). In step (106), the switch SWACT _py is turned off (open), and the input of a control signal to the actuator IACT _py is prohibited, that is, the image blur correction operation is prohibited. Then, the process returns to step (103), and steps (103) to (106) are repeatedly executed. In this state, image blur correction has not been performed.

If an IS start command is received from the camera main unit CMR during execution of steps (103) to (106), step
The process proceeds from step (105) to step (111).

In step (111), control line SAD1
_py, the SAD2 _py b - a level, the blur detection characteristics of angular displacement meter AD _py in the camera shake correction adapted state. Step (11
In 2), the switch SWACT _py is turned on to start image blur correction.

In step (113), encoders ENCZ, E for detecting the position of the zoom ring and the position of the lens for focus adjustment are set.
The state of the NCB is detected, and the focal length f, the photographing magnification β and the eccentric sensitivity S _d (f, β) at that time are read out from the data stored in the ROM from the output information. Note that S _d (f,
β) is matrix data stored in the ROM, and data corresponding to the values of f and β are read out.

At step (114), the upper limit value of the blur correction angle θ _f at the focal length f at the time of photographing is calculated according to θ _f = θ _Tele {1−α + α (f _Tele / f)}. Here, θ _Tele is the maximum blur correction angle at the tele end, f _Tele is the focal length at the tele end, α
Is a constant for determining the rate of change of the shake correction angle limit theta _f. Then, α is set to “0.2”, and “θ _Tele ”, “f”
"0.023 rad" according to Figure 14 the _Tele "Calculating the" f = 100, 170, blurring correction angle upper limit of 300mm "theta _f as" 300mm ", becomes as shown in FIG.

[0104] Further, in FIG. 8 is shown above the Oyobi formula on the image plane obtained with the shake correction amount upper limit value d _IMF, also the displacement limit d _f of the correction optical system ILNS.

Next, at step (115), a coefficient k for converting the shake displacement angle θ in the above equation into the control displacement (d) of the correction optical system ILNS is calculated.

In the following steps (116) to (121), the displacement of the correction optical system ILNS in the pitch direction is regulated.

First, in step (116), step (114)
In a blur correction angle upper limit theta _f determined for comparing the current pitch direction vibration angular displacement theta _p. Then, if the absolute value of the vibration angular displacement theta _p is smaller than the shake correction angle upper limit theta _f Step (1
The process proceeds to step 17) to perform the image blur correction, and if so, the process proceeds to step (120) to interrupt the image blur correction.

In step (117), the shake angular displacement θ _p is converted into the displacement control value d _p of the correction optical system ILNS, and is output to the sample hold circuit SH _p . In step (118),
The control line SSH _p b - a level, a sample-- passing the inoperative a hold circuit SH _p signal d _p. In step (119), a control line SAD1 _p b - a level, the blur detection characteristics of angular displacement meter AD _p camera shake correction adapted state. That is, in steps (117), (118), and (119), a normal image blur correction operation is performed.

[0109] On the other hand, the step (116) the absolute value of the vibration angular displacement theta _p is the flow advances to step (120) if more than shake correction angle upper limit theta _f in, the high control line SSH _p in step (120) Level. Then, a sample-- the output of the hold circuit SH _p is fixed to the input values at that time. Accordingly, the displacement of the correction optical system ILNS will remain fixed in the vicinity of d _f in FIG. 8, the image blur correction is interrupted. In step (121), and a control line SAD1 _p high level, giving a high-pass characteristic to the angular displacement meter AD _p, and returns to its output signal d _p is quickly zero, help image shake correction is resumed.

The above steps (116) to (121) are for controlling in the pitch direction. In the next step (122), the same control is performed for the yaw direction. However, in this figure, this is omitted and shown in step (122).

At the next step (123), the camera body CM
It is determined whether or not an IS stop command has been received from R. If not, the process returns to step (113) to return to pitch and yaw.
Continue image blur correction in the direction, and if received, go to step (1
Returning to 03), image blur correction is stopped in step (106). The flow of steps (113) to (123) is several milliseconds.
Since the repetition is performed in about cycles, camera shake having a band of about 1 to 10 Hz can be sufficiently corrected.

FIGS. 9 and 10 show the effects of the above flow.

[0113] Figure 9 is a blur correction possible angle to the focal length f, the theta _f .theta.max is shown a conventional example, a solid line indicated by a broken line shows the present embodiment. In the conventional example, the change of the correctable angle with respect to the focal length f is large, but in this embodiment, it can be seen that this change is reduced.

In the present embodiment, the reason why the blur-correctable angle on the wide side is set slightly larger than that on the tele side is that the blur is slightly increased when the photographer holds the camera slightly casually on the wide side. However, if the constant α in step (114) of FIG. 7 is set to zero, the shake correction possible angle can be kept completely constant as shown by the dashed line in FIG.

FIG. 10 shows a correction optical system I for the focal length f.
It can be seen that the displacement amount of the LNS is constant irrespective of the focal length f in the conventional example shown by the broken line, but the movable range is restricted on the wide side in the present example shown by the solid line.

In the first embodiment, the blur correction possible angle is made substantially constant irrespective of the focal length, and the usability is improved. However, in the second embodiment of the present invention described below, zooming is performed. The purpose of the present invention is to limit the blur correction range according to the state of occurrence of aberrations due to the operation of the camera, so that a photograph without aberrations can always be obtained.

In designing a zoom optical system having an image blur correction function, aberration is corrected over the entire zoom region even when the correction optical system ILNS is driven to its maximum displaceable value. Is ideal. However, aberrations cannot always be completely corrected due to various restrictions. On the other hand, since the necessity of camera shake correction is important on the telephoto side, it is general that the optical system design emphasizes aberration correction on the telephoto side. As a result, aberrations during image blur correction on the wide side are reduced. growing.

FIG. 11 conceptually shows the state of occurrence of aberration with respect to the displacement d of the correction optical system ILNS. The horizontal axis represents the displacement d, and the vertical axis represents the image degradation G corresponding to the aberration.
G ₀ is the allowable deterioration amount. And the tele end (f = 300mm)
In this case, the aberration is within the allowable range in the entire movable range of the correction optical system ILNS, but when f = 170 mm and 100 mm, the aberration exceeds the allowable value before reaching the maximum displacement (± 2 mm) as shown in the figure.

Therefore, in the second embodiment, the maximum allowable change amount of the correction optical system ILNS at each focal length f is stored in the blur correction microcomputer ICPU, and the change of the optical system during image blur correction is stored. It is restricted according to the value.

FIG. 12 is a flowchart showing the image blur correction operation in the second embodiment.

In FIG. 12, steps (101) to (11)
Step 3) is the same as that of the first embodiment, so step (13)
1) The following will be described.

In steps (111) and (112), image blur correction is started, and in step (113), the blur correction microcomputer ICP is started.
After reading out the focal length f, the photographing magnification β, and the eccentric sensitivity S _d from the ROM in U, in step (131),
It reads the data d _f - more correction optical system displacement allowance data of ILNS.該De - data d _f is decentering sensitivity S _d as well as the focal length f
And a photographing magnification β, and are stored in the ROM as a matrix d _f (f, β) corresponding to each value. In the next step (132), step (115) of the first embodiment is performed.
The calculation of the conversion coefficient k is performed in the same manner as in.

In steps (133) to (138), the displacement control of the correction optical system ILNS in the pitch direction is performed.

First, in step (133), step (11)
In the same manner as in 7), the shake angle displacement θ _p is converted into a displacement control value d _p of the correction optical system ILNS, and output to the sample hold circuit SH _p . In step (134), and compares the displacement tolerance of the read correction optical system ILNS d _f and the current displacement control amount d _p in step (131). And "| d _p | <d _f "
If so, proceed to steps (135) and (136), and step (118)
The image blur correction operation is continued by performing the same operation as in (119). On the other hand, if “| d _p | ≧ d _f ”, step (137),
The process proceeds to (138), and the displacement of the correction optical system ILNS is fixed as in steps (120) and (121).

In the step (139), the above-mentioned step (133)
The control similar to (138) is performed in the yaw direction. Then, in step (140), the IS
It is determined whether or not a stop command has been received. If the command has not been received, the process returns to step (113) to continue image blur correction in the pitch and yaw directions. If the command has been received, the process returns to step (103). In step (106), image blur correction is stopped.

According to each of the above embodiments, the drive range of the correction optical system ILNS is limited according to the zoom of the photographing optical system or the position of the focus adjusting lens. A good image blur correction device can be provided, and a photograph without image deterioration can be provided.

More specifically, in the first embodiment, since the displacement restricting means of the correction optical system ILNS is provided so that the image blur correction possible angle is substantially constant even when the focal length changes, the focal length is changed. However, the panning operability is not reduced, and it is possible to provide an image blur correction apparatus that is always easy to use.

In the second embodiment, the displacement maximum value of the correction optical system ILNS at each focal length is stored in the ROM in the blur correction microcomputer ICPU, and the displacement of the correction optical system ILNS is limited based on the stored maximum value. As a result, image degradation due to aberrations can be prevented without impairing the camera shake correction ability, and thus a high-quality image can always be obtained.

(Modification) In the present embodiment, image blur correction is performed by shifting some lens groups of the photographing optical system in a direction perpendicular to the optical axis. The same effect can be obtained in the case of performing. The variable apex prism has a function of a variable apex prism by sealing a liquid between two parallel plane glasses proposed in Japanese Patent Application Laid-Open No. 2-59718 by the present applicant and changing the relative angle of the glasses. Then, image blur correction is performed by tilting the optical axis. When the variable apex angle prism is disposed inside the photographing optical system, the proportional constant between the displacement angle and the blur correction angle of the variable apex angle prism changes due to zooming, and the state of occurrence of aberration also changes. I do. Therefore, the flow of the first and second embodiments of the present invention will be described.
Is applied to the variable apex angle prism drive control, the same effect can be obtained.

Further, the first embodiment and the second embodiment are combined to restrict the driving when the displacement of the correction optical system ILNS reaches the smaller limit value of the two types of displacement limiting devices. Examples are easily conceivable.

(Correspondence between Invention and Embodiment) In the above embodiment, the correction optical system ILNS is used as the image blur correction means of the present invention, and the angular displacement meter AD is used as the shake detection means of the present invention. ), (117) or steps (132), (13
The function part of the image blur correction microcomputer ICPU which executes 3) is provided to the signal forming means of the present invention by the image blur correction control circuit ICN.
The drive means T and the image blur correction actuator IACT is present invention, the functional portion of the image blur correction microcomputer ICPU maximum permissible drive of the present invention for performing step (131) of the step (114) or 12 of FIG. 7 In the range forming means, FIG.
Perform step (116) or step (134) in FIG.
The function part of the microcomputer ICPU for image blur correction is
Steps (118) and (120) in FIG. 7 or steps in FIG.
Image stabilization microcomputer I that performs steps (135) and (137)
The functional parts of the CPU correspond to the drive control means of the present invention , respectively.

As described above, according to the present invention, the relationship between the shake of the apparatus and the operation amount of the image shake correcting means for correcting the image shake caused by the shake is determined by the variable power optical group or the focus adjustment. In the image blur correction device that changes according to the position of the group, the maximum shake amount that can be corrected in each setting state of the variable power optical group or the focus adjustment group is appropriately set, and the image blur correction unit The operation range is prevented from including the range in which the aberration is largely generated, and the panning operability is improved in each setting state of the variable power optical group or the focus adjustment group, and the usability of the apparatus is improved. Can be done.

[Brief description of the drawings]

FIG. 1 is a configuration diagram schematically showing a camera provided with an apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram showing an imaging optical system used in each embodiment of the present invention.

FIG. 3 is a diagram showing a mechanical and electrical configuration and an amplification degree of the angular displacement meter according to the first embodiment of the present invention.

FIG. 4 is a perspective view showing a correction optical mechanism according to the first embodiment of the present invention.

FIG. 5 is a block diagram illustrating an image blur correction control circuit according to the first embodiment of the present invention.

FIG. 6 is a flowchart showing the operation on the main body side of the camera provided with the apparatus of the first embodiment of the present invention.

FIG. 7 is a flowchart showing an image blur correction operation on the lens side of a camera provided with the apparatus according to the first embodiment of the present invention.

FIG. 8 is a diagram illustrating a relationship between a focal length, an upper limit value of a blur correction angle, an upper limit value of a displacement of a correction optical system, and the like in the first embodiment of the present invention.

FIG. 9 is a diagram for explaining the operation of the first embodiment of the present invention.

FIG. 10 is a diagram for explaining the operation of the first embodiment of the present invention.

FIG. 11 is a diagram for explaining the operation of the second embodiment of the present invention.

FIG. 12 is a flowchart showing an image blur correction operation on the lens side of a camera provided with the apparatus according to the second embodiment of the present invention.

FIG. 13 is a diagram for describing an image blur correction control system in this type of apparatus.

FIG. 14 is a diagram showing the eccentric sensitivity, the maximum displacement, the maximum value of the displacement of the image, and the shake-correctable angle at each zoom position of the optical system arranged in this type of apparatus.

[Description of sign]

 CMR camera main unit LNS lens ILNS correction optical system ICPU Image blur correction microcomputer AD angular displacement meter IACT Image blur correction actuator ICNT Image blur correction control circuit SH Sample hold circuit ENCZ Encoder for zoom position detection ENCB Encoder for focus adjustment lens position detection

Continuation of front page (56) References JP-A-2-309329 (JP, A) JP-A-3-161722 (JP, A) JP-A-3-83006 (JP, A) JP-A-3-87716 (JP) JP-A-1-131521 (JP, A) JP-A-1-131522 (JP, A) JP-A-3-122629 (JP, A) JP-A-3-96931 (JP, A) 4-212940 (JP, A) JP-A-3-248136 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03B 5/00 G02B 7/10

Claims (1)

(57) [Claims] 1. An image blur correction device used together with an image forming optical system having at least a variable power optical group or a focus adjustment group, comprising: an image blur correction means; an output of a shake detection means for detecting a shake of the apparatus; Changes according to the zoom position of the zoom optical group
Changes depending on the data to be changed or the position of the focus adjustment group .
Depending on the data, and a signal forming means for forming a drive signal for operating the image blur correction means, and drive means for driving the image blur correcting means on the basis of a driving signal of the signal formation means, said variable It changes according to the magnification position of the magnification optics group.
Data that changes depending on the position of the focus adjustment group.
Of the image blur correction means by the driving means based on the
Maximum permissible driving range formation to form the maximum permissible driving range signal
Means, the maximum allowable driving range signal and the driving signal
Based on the comparison means to be compared and the comparison result of the comparison means
Depending on the position of the variable power optical unit or the position of the focusing unit
The image blur correction hand within the maximum allowable driving range
Drive for driving and controlling the drive means so that the stage is driven
Control means, the zoom position of the zoom optical group, or
The position of the focus adjustment group is determined by the image blur correction means.
The change in the large blur correction angle is the maximum allowable of the image blur correction means.
As compared with the case where the driving range is fixed,
Image stabilizer, characterized in that the.