JPH0566450A - Image blurring correction device - Google Patents

Abstract

PURPOSE:To make handleability excellent without deteriorating operability in panning and to give a picture which has no image deterioration. CONSTITUTION:A limit means ICPU which decides an upper limit value in the driven displacement of a correction optical mechanism ILNS in accordance with the position of a variable power optical group or a focusing group and limits the displacement of the correction optical mechanism based on the decided upper limit value is provided in an image blurring correction means. When an image blurring correction range is changed because of zooming, the displacement of the correction optical mechanism, that is, the image blurring correction range is limited in accordance with the above change, so that the image blurring correction range is prevented from becoming too large on a wide side or the image blurring correction range is prevented from including also the part of an area where the aberration is large.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming optical system having at least a variable magnification optical group or a focus adjusting group, a correction optical mechanism for decentering or tilting an optical axis of the image forming optical system, and the image forming optical system. The present invention relates to an improvement of an image blur correction device including a vibration detection unit that detects a vibration applied to a system, and an image blur correction unit that drives the correction optical mechanism based on a signal from the vibration detection unit to perform image blur correction. It is a thing.

[0002]

2. Description of the Related Art Conventionally, various devices for correcting image blur of a camera 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, and a relative angle between the two glass plates is changed to cause a prism action to polarize a light beam. It is proposed in Japanese Patent Laid-Open No. 2-59718. This is to add the variable apex angle prism to the photographing optical system and eliminate the image blur on the image plane due to the blur of the photographing optical system by the light beam deflection action of the variable apex prism.

In general, the variable apex angle prism is arranged in front of the photographing optical system. In that case, the coefficient of the prism driving angle with respect to the blur amount of the photographing optical system is constant regardless of the characteristics of the photographing optical system. is there. That is, even if the taking optical system is a zoom lens, it is not necessary to change the control constant for image blur correction. However, in this method, the effective aperture of the variable apex angle prism needs to be increased, which causes a problem that the device becomes large.

Therefore, the applicant of the present invention has proposed that the image on the image plane is moved by displacing a part of the optical system in the photographing optical system in the direction perpendicular to the optical axis to eliminate the image blur. It is proposed in Kaisho 62-44707 and the like. This blur correction principle is shown in FIG.

In FIG. 13, reference numeral 1 is a photographic optical system including a variable power system, a focus adjustment system and a correction optical system, and 2 is 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 is an angular displacement meter, which is a photographing optical system 1.
The shake angle displacement θ of is detected and output. 4 is the displacement angle θ
Is a coefficient converter for converting into a displacement signal d necessary for eliminating image blur.

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

The relationship between the blur angle displacement θ of the photographing optical system 1, the displacement amount d _L of the correction optical system 2 and the image movement amount (displacement amount) 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 is θ [rad with respect to the front principal point.
] The amount of image displacement d _IM when the angular blur occurs is d _IM = f (1 + β) · θ. On the other hand, if the ratio of the image displacement amount d _IM to the displacement amount d _L of the correction optical system 2 is referred to as the eccentricity sensitivity S _d , then d _IM = S _d · d _L. Since the eccentricity sensitivity S _d is a function of the focal length f and the photographing magnification β, it can be expressed as S _d = S _d (f, β). Since the principle of image blur correction is to eliminate the image blur (formula) due to the angular blur of the photographing optical system 1 by the image displacement (formula) due to the lens displacement, 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 ...

[0009]

However, the above-mentioned conventional example has the following problems.

That is, by zooming or focusing, "f", "(1 + β)", "S _d (f,
β) ”value changes, but the maximum displaceable amount d _L max of the correction optical system 2 remains unchanged. Then, according to the formula, the shake correction possible angle θmax changes depending on the focal length f. And, in general, the eccentricity sensitivity S _d (f, β) due to zooming
Although the value of becomes larger on the tele side, it is 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 tele side. This state is shown in FIG.

Then, in this case, the following problems occur.

1) When holding a camera with a zoom lens, the human hand shake amplitude is almost constant regardless of the focal length. On the other hand, the shake compensation possible range must be larger than the normal camera shake amplitude, but if it is too large, it gives a sense of discomfort to the photographer during panning operation, and is rather difficult to use.

2) The large blur correction range on the wide side means that the aberration of the optical system also increases 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, even if the photographer performs a panning operation on the wide side as well, the image blur correction device may use the maximum area portion of the blur correction range in response to the panning operation. If exposure is performed at this time, image deterioration due to aberration occurs even if camera shake correction is performed accurately.

SUMMARY OF THE INVENTION In view of the above points, an object of the present invention is to provide an image blur correction device which is capable of not only degrading panning operability but also improving usability and giving a photograph without image deterioration. Is.

[0015]

According to the present invention, the upper limit value of the drive displacement of the correction optical mechanism is determined in the image blur correction means in accordance with the position of the variable power optical group or the focus adjustment group, and based on this. Limiting means for limiting the displacement of the correction optical mechanism is provided.

[0016]

The image blur correction range changes due to zooming or the like. In this case, the displacement of the correction optical mechanism, that is, the image blur correction range is limited according to the change, and the image blur correction range on the wide side is reduced. It is set so as not to be too wide, and the image blur correction range does not include a region portion having a large aberration.

[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 a zoom of 3 times from 100 mm to 300 mm, the wide end (f = 100 mm) in the upper part, and the lower part in the upper part. Tele end (f
= 300 mm) shows the lens arrangement.

This image-forming optical system is composed of four groups, and the fourth group is fixed and the first, second, and third groups are moved during zooming.
The first group moves during focus adjustment. Then, by displacing the second group in the direction perpendicular to the optical axis, the image on the image plane is displaced to perform image blur correction.

The characteristics relating to the image blur correction of this imaging optical system are as shown in FIG.

When the subject distance is infinite, the eccentricity sensitivities S _d (f, β) at f = 100 mm and 300 mm are respectively "2.
5 ”and“ 3.5 ”(see FIG. 14). On the other hand, the maximum displaceable amount 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 amount of the image d _IM max
Is ± 5 mm ”and“ ± 7 mm ”from the above formula, and the shake compensation possible angle θmax is
0 rad "and" ± 0.023 rad ". That is, it is understood that when the blur correction possible amount is compared with the blur angle, it is possible to correct the blur angle on the wide side at least twice as much as on the tele side.

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

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 detachable from the camera body CMR.

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

The CCPU is an in-camera microcomputer (hereinafter referred to as a microcomputer), which is a one-chip microcomputer having a ROM, a RAM, and an A / D conversion function. The in-camera microcomputer CCPU performs a series of camera operations such as automatic exposure control, automatic focus adjustment, film winding, etc. in accordance with the camera sequence program stored in the ROM. Therefore, 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 the output to the MR via the signal line DLC.

SNS is a line sensor for focus detection (hereinafter simply referred to as sensor) composed of CCD or the like, and SDR is a drive circuit for driving the sensor SNS in response to a command from the microcomputer CCPU in the camera. The 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 M, the focus glass PG, and the pentaprism PP, and the output signal is input to the microcomputer CCPU in the camera and used for automatic exposure control (AE) according to a predetermined program.

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

SW1 and SW2 are switches interlocked with a release button (not shown). The switch SW1 is turned on when the release button is pressed in the first step, and the switch SW2 is turned on when the release button is pressed up to the second step. .. As will be described later, the in-camera microcomputer CCPU 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 when the switch SW2 is turned on. The switch SW2 is connected to the "interruption input terminal" of the microcomputer CCPU in the camera, so that even if the program is executed when the switch SW1 is on, an interrupt is generated by turning on the switch SW2, and it is possible to immediately shift to a predetermined interrupt program.

MTR1 is a film feeding mode, and MTR2 is a mirror up / down mode and a shutter spring charge mode.
Each of the drive circuits MDR1 and MDR2 controls forward / reverse rotation.

MG1 and MG2 are magnets for starting the leading and trailing shutter shutters, respectively, and amplifying transistors TR1 and T
The power is supplied at R2, and the shutter microcomputer STR controls the shutter STR.

Next, the structure on the lens LNS side will be described.

The LCPU is a microcomputer in the lens and is a one-chip microcomputer having ROM, RAM and A / D conversion functions like the microcomputer CCPU in the camera. The microcomputer LCPU in the lens adjusts the focus adjustment lens FL in accordance with a command sent from the camera body CNR via the signal line DCL.
The drive control of the NS and the drive control of the diaphragm are performed. In addition, various operating conditions of the lens (how much the focus adjustment optical system has been driven, how many stops the aperture has been stopped, etc.) and parameters (open F number, focal length, coefficient of defocus amount vs extension amount, etc.) ) Is transmitted to the camera side via the signal line DLC.

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

FDR is a drive circuit for the motor FMTR, which is driven by a signal from the lens microcomputer LCPU.
Controls forward / reverse rotation of the FMTR and brakes.

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

Therefore, once the focus adjustment command is sent from the camera body CMR, the camera microcomputer CCPU
Does not need to be involved in lens driving at all until the lens driving is completed. Further, the contents of the counter can be sent to the camera body CMR if necessary.

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

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

The ICPU is an image blur correction microcomputer that controls the image blur correction operation and controls the lens LNS from the camera body CMR.
To the camera body CMR from the lens LNS, and the output signal from the microcomputer ICPU is input to the lens microcomputer LCPU. That is, communication with the microcomputer CCPU in the camera is performed only with the microcomputer LCPU in the lens, and the image stabilization microcomputer IC
The PU takes a form of intercepting communication between the two. Communication from the image blur correction microcomputer ICPU to the camera microcomputer CCPU is performed by the lens microcomputer LCPU.
Through.

AD is an angular displacement meter for detecting blurring of the lens LNS. For example, Japanese Patent Application No.
A sensor utilizing the inertia of the fluid in the cylindrical case of No. 201183 is used. The angular displacement output θ of the angular displacement meter is transmitted to the image blur correction microcomputer ICPU. Further, the image blur correction microcomputer ICPU sends control signals SAD1 and SAD2 for controlling the response frequency characteristic of the angular displacement meter.

ICNT is an image blur correction control circuit described later, which has a filter, an amplifier, a switch, and the like, and drives and controls an image blur correction actuator IACT described later. For this purpose, a PSD and an image blur correction microcomputer ICPU are provided. It has a signal input / 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.

The IACT is an image blur correcting actuator provided in the support mechanism, and is composed of a magnetic circuit made of a permanent magnet and a coil moving in the magnetic circuit to displace the correction optical system ILNS. ..

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

SWIS is a main switch of the image blur correction system. When the switch SWIS is turned on, the image blur correction microcomputer ICPU and its peripheral circuits are powered on, 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 communicated to the image blur correction microcomputer ICPU via the lens microcomputer LCPU, and the motor IMTR is driven to start the image blur correction operation.

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 simplified. Explain.

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 around a bearing 27. Further, 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 portion and the floating body 22.

Next, the electrical components will be described.

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

A portion B surrounded by a dotted line is a control portion for changing the parameter of the sensor. In the figure, two switches SWAD1 and SWAD2 are image blur correction microcomputer I.
A switch which is on / off controlled by the CPU on the control lines SAD1 and SAD2. When the line goes high, the switch is turned on (closed). When the switch is off (open), the angular displacement output θ is the operational amplifier 29.
Is amplified by an amplification factor of "R ₃ / R ₀ ", but when the switch is turned on, the resistance R ₀ or the resistance R ₁ or the resistance R ₂
Are connected in parallel, and as a result, the combined resistance decreases, and the amplification factor increases. Then, for example, "R ₀ = R ₁ = R ₃ = 2R
₂ ", the amplification factor of the operational amplifier 29 by turning on / off the switch is set as shown in FIG. 4 (b).

The portion C surrounded by the dotted line is the winding coil 24.
The operational amplifier 30 serves as a buffer in the driver unit for driving the. Therefore, a current according to the output voltage of the control unit B flows through the winding coil 24. That is, since the coil current proportional to the angular displacement (θ) of the floating body 24 flows, the floating body 24 is given a restoring force proportional to the angular displacement (θ), and this restoring force is switched by the size of the switches SWAD1 and SWAD2. be able to. The greater the restoring force, the more quickly the angular displacement output θ converges to “0”, and the sensor characteristic has a high high-pass characteristic, that is, the low-frequency shake detection capability becomes low.

The angular displacement output θ saturated during panning escapes quickly from the saturated region.

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

Although FIG. 1 shows the image blur correction mechanism for only one axis, camera shake occurs in the two-dimensional directions of up, down, left and right. Therefore, an actual lens detects blurs in the two axis directions and the correction optical system. ILNS must also work two-dimensionally.

Therefore, FIG. 4 shows in detail the support mechanism of the correction optical system ILNS. In this correction optical mechanism, a correction lens 41 corresponding to the correction optical system ILNS in FIG. 1 is operated in a direction of correcting camera shake in a plane orthogonal to the optical axis, thereby obtaining an image shake suppressing effect on the image forming surface. Is.

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

In FIG. 4, a fixed frame 43 for holding the correction lens 41 is a slide bearing 44 made of 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. Further, the pitch slide shaft 45p is attached to the holding frame 46.
Is attached to the protrusion 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. The pitch coil 48p is provided with a slit 411p,
The position of the fixed frame 43 in the pitch direction 42p is detected by the relation between the light projector 412p (infrared light emitting diode IRED) and the light receiver 413p (semiconductor position detection element PSD).

The above is the drive mechanism in the pitch direction.

Next, the drive mechanism in the yaw direction (direction of the arrow 42g) will be described.

P is formed on the protrusions 46b and 46c on the holding frame 46.
A slide bearing 44y such as OM is mounted. On the other hand, a yaw slide shaft 45y is fixedly mounted on a protrusion 414a on a 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 (arrow 42y direction). Further, the fixed frame 43 is provided with a yaw coil 48y, and a yaw magnet 49y sandwiching the yaw coil is provided.
The fixed frame 43 is also driven in the yaw direction 42y by the interaction of the magnetic field formed by the yaw yoke 410y. The yaw coil 48y is provided with a slit 411y to detect 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 has the configuration shown in FIG.

The flat portion 43c provided at the lower left portion of the fixed frame 43 is restricted in position in the optical axis direction by a projection 50 provided on a lens barrel fixing portion (not shown) for preventing blurring. 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-mentioned configuration.
This is because there are two positions, c, and at least three position restriction parts (holding parts) are required to restrict the action of the fixed frame 43 only in the shift direction. Therefore, two protrusions 50
The position of the flat surface portion 43c is regulated from the front and back sides (one on the back side is not shown) to prevent the fixed frame 43 from moving (flaking) in the optical axis direction.

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

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

FIG. 5 shows the image blur correction control unit in detail. The portion surrounded by the dotted line corresponds to the image blur correction control circuit ICNT of FIG. The circuit ICNT, the angular displacement meter AD, etc. are provided for driving the pitch direction and the yaw direction, respectively. Each of the elements for the pitch direction and the name of the signal line have p for the yaw direction. Is added with the subscript of y.
However, in the following description, the pitch and yaw directions will be collectively described, and the subscripts p and y will be omitted.

AD is the above-mentioned angular displacement meter, which outputs the shake angle displacement (θ) of the lens barrel. SAD1 and SAD2 are control lines for changing the blur detection characteristic of the angular displacement meter AD described above. When the lines SAD1 and SAD2 are at a high level, the AD high pass characteristic of the angular displacement meter is enhanced to improve the detection capability for low frequency blur. 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 the high level to expedite the return of the angular displacement output θ to “0”.

The angular displacement output θ is a shake correction microcomputer ICP.
The coefficient is converted in U to become the control signal d, which is input to the sample hold circuit SH in the image blur correction control circuit ICNT. The sample-hold circuit SH is controlled by the control line SSH from the shake correction microcomputer ICPU, and when the line SSH is low level, the control signal d changes the circuit SH.
When the line SSH is at the high level, the control signal d at the time when the line is at the high level is held and continuously output.

SWACT is a switch for turning on / off the control signal input to the actuator IACT, which is controlled by the shake correction microcomputer ICPU, and the switch SWA
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, and this output signal V
_ACT becomes the applied voltage to the actuator IACT.

When the actuator IACT operates, the correction optical system ILNS is driven, and the IR fixed to the slit SLT and the lens barrel which move integrally with the optical system ILNS.
Due to 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 inversely input to 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 the displacement corresponding to the control signal d.

Next, the camera body CMR having the above structure
The operation of each of the lens and the lens LNS will be described with reference to FIGS. 6 and 7.

First, the operation of the camera body CMR side will be described using the flowchart of FIG.

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

In step (002), the state of the switch SW1 which is turned on by pressing the release button in the first step is detected. When SW1 is off, the process proceeds to step (003) and 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.
The process is repeated until W1 is turned on or the power switch is turned off.

When the switch SW1 is turned on, the process proceeds 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), and when the camera microcomputer CCPU sends a communication command to the lens microcomputer LCPU via the signal line DCL. The in-lens microcomputer LCPU 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 for starting the image blur correction operation is transmitted to the lens LNS side.

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

In step (014), the "exposure calculation" subroutine for obtaining the exposure control value is executed. The suble
In Chin, the Apex arithmetic expression “Av + Tv = Bv + S
v ”and a predetermined program diagram, shutter value Tv
And the aperture value Av are determined and stored in a predetermined address of the RAM.

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

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

The subroutine flow of the steps (015) and (016) is the same as that of the applicant of the present invention.
No. 4, etc., and detailed description thereof is omitted here.

In step (017), the "lens drive" subroutine is executed. In the subroutine, the camera body C
The drive pulse number of the focus adjustment lens FLNS calculated in step (016) on the MR side is set to the microcomputer LCPU in the lens.
To the microcomputer LCPU in the lens after that
Drives and controls the motor FMTR according to a predetermined acceleration / deceleration curve. After the driving is completed, an end signal is transmitted to the microcomputer CCPU in the camera, the subroutine is completed, and the process returns to step (002).

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

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

When the switch SW2 interrupt is entered during execution of the step surrounded by the broken line, the process proceeds to step (022) via step (021).

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

At step (023), the film is wound up to finish photographing 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 will not be described in detail.

Next, the image blur correction operation performed on the lens LNS side using the flowchart of FIG. 7 will be described. In each step, the subscript py is added to indicate that the pitch and yaw motions are sequentially performed.

In step (101), the image blur correction main switch SWIS is turned on to turn on the image blur correction microcomputer ICPU, its peripheral circuits and the angular displacement meter AD. As a result, the image blur correction microcomputer ICPU starts executing the program after step (102) in FIG.

At step (102), all flags and all variables in the image blur correction microcomputer ICPU are cleared and set to "0". In step (103), the control line 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 , and the displacement of the correction optical system ILNS is started from a state close to the origin at the start of image blur correction. In step (104), the control line SSH _{py is set} to a low level to permit passage of the control displacement d _py .

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

If an IS start command is received from the camera body CMR while executing steps (103) to (106),
From (105), the process proceeds to step (111).

In step (111), the control line SAD1
_py and SAD2 _py are set to the low level, and the shake detection characteristic of the angular displacement meter AD _{py is set to} the camera shake correction compatible state. Step (11
In 2), the switch SWACT _py is turned on to start image blur correction.

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

In step (114), the blur correction angle upper limit value 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)}. Where 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 upper limit value θ _f . Then, α is "0.2", and "θ _Tele " and "f
_If " _Tele " is set to "0.023 rad" and "300 mm" according to FIG. 14 and the blur correction angle upper limit value θ _f at "f = 100, 170, 300 mm" is calculated, it becomes as shown in FIG.

Further, FIG. 8 also shows the blur correction amount upper limit value d _IMf on the image plane and the displacement upper limit value d _f of the correction optical system ILNS, which are obtained by using the above-mentioned and equations.

Next, at step (115), the 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 next steps (116) to (121), the displacement of the correction optical system ILNS in the pitch direction is restricted.

First, in step (116), in step (114)
The blur correction angle upper limit value θ _{f obtained in step 3} and the current pitch direction blur angle displacement θ _p are compared. If the absolute value of the shake angle displacement θ _p is smaller than the shake correction angle upper limit value θ _f , step (1
The process moves to 17) to perform image blur correction, and if it is above, the process moves to step (120) to interrupt the image blur correction.

In step (117), the blur angle displacement θ _p is converted into the displacement control value d _p of the correction optical system ILNS and output to the sample hold circuit SH _p . In step (118),
The control line SSH _{p is set} to low level, the sample-hold circuit SH _p is deactivated, and the signal d _p is passed. In step (119), the control line SAD1 _{p is set} to low level, and the shake detection characteristic of the angular displacement meter AD _{p is set to} the camera shake correction compatible state. That is, in steps (117), (118) and (119), normal image blur correction operation is performed.

On the other hand, if the absolute value of the shake angle displacement θ _p is equal to or larger than the shake correction angle upper limit value θ _f in step (116), the process proceeds to step (120), and the control line SSH _p is set high in step (120). Level. Then, the output of the sample hold circuit SH _p is fixed to the input value at that time. Therefore, the displacement of the correction optical system ILNS remains fixed near d _f in FIG. 8, and the image blur correction is interrupted. In step (121), the control line SAD1 _{p is set} to a high level, the angular displacement meter AD _p is given a high-pass characteristic, and its output signal d _p quickly returns to zero to help restart the image blur correction.

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

In the next step (123), the camera body CM
It is judged whether or not the IS stop command is received from R, and if not received, the process returns to step (113) and the pitch and yaw are returned.
Direction image blur correction is continued, and if it is received, step (1
Return to 03) and stop image blur correction in step (106). The flow of steps (113) to (123) is several msec.
Since it is repeatedly performed in a cycle of about 10 seconds, it is possible to sufficiently correct camera shake having a band of about 1 to 10 Hz.

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

FIG. 9 shows the blur correction possible angle with respect to the focal length f, where θ max shown by the broken line is a conventional example and θ _f shown by the solid line is this embodiment. In the conventional example, the change of the correctable angle with respect to the focal length f is large, but it can be seen that this change is alleviated in the present example.

In the present embodiment, the wide-angle shake compensation possible angle is made slightly larger than that of the telephoto side in consideration of the fact that the photographer holds the camera slightly unintentionally on the wide-side, and the blur becomes a little large. However, if the constant α in step (114) of FIG. 7 is set to zero, the shake compensation possible angle can be kept completely constant as shown by the alternate long and short dash line in FIG.

FIG. 10 shows the correction optical system I for the focal length f.
It is understood that the displaceable amount of the LNS is constant regardless 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 correctable angle is made substantially constant regardless of the focal length, and the usability is improved. However, in the second embodiment of the present invention described below, This is intended to regulate the blur correction possible range according to the situation of aberration occurrence due to the zoom operation so that a photograph without aberration can always be obtained.

In designing a zoom optical system having an image blur correction function, aberrations are corrected over the entire zoom region even when the correction optical system ILNS is driven to its maximum displaceable value. It is ideal to be there. However, it is not always possible to completely correct aberrations due to various restrictions. On the other hand, since the necessity of camera shake correction is important on the tele side, it is general that the design of the above optical system emphasizes aberration correction on the tele side. growing.

FIG. 11 conceptually shows how aberration occurs with respect to the displacement amount d of the correction optical system ILNS. The horizontal axis represents the displacement amount d and the vertical axis represents the image deterioration amount G corresponding to the aberration amount.
G ₀ is the allowable deterioration amount. And tele end (f = 300mm)
Then, the aberration is within the allowable range in the entire movable region of the correction optical system ILNS, but at f = 170 mm and 100 mm, the aberration exceeds the allowable value before reaching the maximum displacement amount (± 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 shake correction microcomputer ICPU, and the change of the optical system at the time of image shake correction is stored. It is restricted according to the value.

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

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

Image blur correction is started in steps (111) and (112), and the blur correction microcomputer ICP is started in step (113).
After reading the focal length f, the imaging magnification β, and the eccentricity sensitivity S _d from the ROM in the U, in step (131), the same ROM is also used.
The displacement allowable amount data d _f of the correction optical system ILNS is read out. The data d _f has the same focal length f as the eccentricity sensitivity S _d.
And a function of the imaging magnification β, and are stored in the ROM as a matrix d _f (f, β) corresponding to each value. The next step (132) is the step (115) of the first embodiment.
Similarly, the conversion coefficient k is calculated.

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

First, in step (133), step (11
Similarly to 7), the blur angle displacement θ _p is converted into the displacement control value d _p of the correction optical system ILNS and output to the sample hold circuit SH _p . In step (134), the displacement allowable value d _f of the correction optical system ILNS read in step (131) is compared with the current displacement control amount d _p . Then, "| d _p | <d _f "
If so, move to steps (135) and (136), and go to step (118)
, Perform the same operation as (119) to continue the image blur correction operation. 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 step (139), the above step (133)
The same control as in steps (138) to (138) is performed in the yaw direction. Then, in step (140), the camera body CMR sends the IS
It is judged whether or not a stop command is received.If not received, the process returns to step (113) to continue the image blur correction in the pitch and yaw directions, and if it is received, the process returns to step (103), The image blur correction is stopped in step (106).

According to each of the above-described embodiments, the drivable range of the correction optical system ILNS is limited in accordance with the zoom of the photographing optical system or the position condition of the focus adjusting lens. It is possible to provide a good image blur correction device and to provide a photograph without image deterioration.

Specifically, in the first embodiment, since the displacement restricting means of the correction optical system ILNS is provided so that the image blur correctable angle becomes substantially constant even if the focal length changes, the focal length is changed. Even if the panning operability does not deteriorate, it is possible to provide an image blur correction device that is always easy to use.

Further, in the second embodiment, the maximum displacement 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 this. As a result, the image deterioration due to the aberration can be prevented without impairing the camera shake correction ability, and it is possible to always obtain a high quality image.

(Modification) In the present embodiment, the image blur correction is performed by shifting a part of the lens group of the photographing optical system in the direction perpendicular to the optical axis, but this is performed by the variable apex angle prism. The same effect can be obtained when doing. A variable apex angle prism has a variable apex angle prism function, which is proposed in Japanese Patent Laid-Open No. 2-59718 by the present applicant, in which a liquid is enclosed between two parallel plane glass and the relative angle of the glass is changed. The image blur correction is performed by tilting the optical axis. When the variable apex angle prism is arranged inside the photographing optical system, the proportional constant of the displacement angle of the variable apex angle prism and the shake correction angle changes due to zooming, and the occurrence state of aberration also changes. To do. Therefore, the flow of the first and second embodiments of the present invention
Is applied to the variable apex angle prism drive control, the same effect can be obtained.

Further, by combining the first and second embodiments, the drive is restricted when the displacement of the correction optical system ILNS reaches the smaller limit value of the two types of displacement restricting devices. Examples are easily conceivable.

[0131]

As described above, according to the present invention,
In the image blur correction means, there is provided a limiting means for determining the upper limit value of the drive displacement of the correction optical mechanism according to the position of the variable power optical group or the focus adjustment group, and limiting the displacement of the correction optical mechanism based on this. When the image blur correction range changes due to zooming or the like, the displacement of the correction optical mechanism, that is, the image blur correction range is limited according to the change so that the image blur correction range on the wide side does not become too wide. Alternatively, the image blur correction range does not include even a region portion having a large aberration.
Therefore, it is possible to improve the usability without deteriorating the panning operability, and it is possible to provide a photograph without image deterioration.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an outline of a camera provided with a device of 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 in the first embodiment of the invention.

FIG. 5 is a block diagram showing 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 device 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 equipped with the apparatus of the first embodiment of the present invention.

FIG. 8 is a diagram showing the relationship between the focal length and the shake correction angle upper limit value, the displacement upper limit value of the 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 which similarly illustrates 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 equipped with a second embodiment device of the present invention.

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

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

[Explanation of sign]

 CMR camera body 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 zoom position detection encoder ENCB Encoder for detecting lens position for focus adjustment

Claims (3)

[Claims] 1. An imaging optical system having at least a variable magnification optical group or a focus adjustment group, a correction optical mechanism for decentering or tilting an optical axis of the imaging optical system, and a vibration applied to the imaging optical system. In an image blur correction device comprising: a vibration detection unit for driving the correction optical mechanism based on a signal from the vibration detection unit to perform an image blur correction;
A limit that determines the upper limit of the drive displacement of the correction optical mechanism according to the position of the variable power optical unit or the focus adjustment unit in the image blur correction unit, and limits the displacement of the correction optical mechanism based on this. An image blur correction device comprising means. 2. The upper limit value determining means for determining the upper limit value to regulate the change of the image blur compensable range on the object side due to the movement of the variable power optical group or the focus adjusting group in the limiting means to be substantially constant. The image blur correction device according to claim 1, wherein the image blur correction device is provided. 3. The limiting means has a displacement allowable limit storage value of the correction optical mechanism according to the position of the variable power optical group or the focus adjustment group, and limits displacement of the correction optical mechanism according to the stored value. The image blur correction device according to claim 1, wherein the image blur correction device is provided.