JPH06308563A - Image blurring prevention device - Google Patents

Abstract

PURPOSE:To bring the operating range of a vibration-proof optical system near to a circular shape by a simple operation area limit arithmetic operation. CONSTITUTION:As for the image blurring prevention device respectively and almost independently driving an image blurring correction optical means ICPU in two mutually nearly orthogonal directions; a displacement detecting means detecting the displacement of a correction optical mechanism ILNS in reference to respective shafts in two directions and a control means ICNT limiting the displacement of the two directions and having data for limit as the table of two directions when the output of the displacement detecting means of the two directions reaches specified relation are provided, and the operating range of the image blurring correction optical system ILNS approximates to the circular shape by splitting the range, and this device rapidly judges whether it is within the operating range or not by comparing the data of boundary with the coordinate of the correction optical system ILNS.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a correction optical mechanism provided with two sets of driving means which are independently driven in two directions substantially orthogonal to each other in order to correct a two-dimensional image blur occurring on an image plane. The present invention relates to an improvement of an image blur correction device having a.

[0002]

2. Description of the Related Art Among various kinds of blurring occurring in a camera or the like, the one that most affects image blurring on a photographing screen is shift blurring (imaging of an image) caused by angular blurring of the photographing optical axis (flapping of the photographing optical axis). This is a translational movement of the image on a plane perpendicular to the optical axis, that is, on the image plane. Then, for the sake of convenience, the angular deviation of the photographing optical axis is decomposed into angular deviations in the up-down direction (pitch direction) and the left-right direction (yaw direction) to detect the deviation,
A two-dimensional blur on the image plane is corrected by driving the correction optical system, which is a part of the photographing optical system, in the vertical and horizontal directions independently on the plane circle perpendicular to the photographing optical axis based on the detection signal. is doing.

As a concrete example applying this principle,
The present applicant has filed applications such as JP-A-63-49729 and JP-A-3-188340.

In these applications, the correction optical system can be driven in the vertical and horizontal directions in a plane perpendicular to the photographing optical axis, independently in the vertical and horizontal directions. It has been proposed to provide control means.

However, the above-mentioned conventional example has the following drawbacks. That is, the blurring direction of the photographing optical axis due to camera shake during handheld photographing falls within a cone having an apex angle 2θ ₀ with the reference direction as the center line when the direction of the photographing optical axis is used as a reference. Therefore, the image blur correction device needs to have a blur correction range of ± θ ₀ in each of the pitch and yaw directions, and the drive mechanism of the correction optical system has a drive amount ± d ₀ corresponding to the angle ± θ _0. The design of the department is done. However, in actuality, in order to obtain a sufficient blur correction effect, the drive amount is generally set to "± d _max " which is slightly larger than the amount corresponding to the actual camera shake amplitude ± d ₀ . Then, as shown in FIG. 13, the correction optical system can be independently driven in the vertical and horizontal directions by “± d _max ”, but the maximum displacement “± d _max ” or “−d _max ” can be simultaneously performed in the vertical and horizontal directions. _When " _max " occurs, the displacement amount from the origin of the correction optical system is "(√2) d _max ".
Therefore, it becomes about 1.4 times d _max . That is, judging from the camera shake characteristics, it is sufficient for the correction optical system to move within a circle having a radius d _max with respect to the origin, but a displacement of d _max or more occurs in a certain specific direction. Moreover, although such a displacement is unlikely to occur, it is necessary to secure a large space around the correction optical system in consideration of this large displacement. The problem is that it becomes unnecessarily large.

FIG. 14 is a diagram for explaining the above problem. This figure shows the correction optical system viewed from the direction of the image plane.
L ₀ represents the space occupied by the correction optical system or when the frame holding the correction optical system is located at the origin, and L ₁ is the space above
₂ is displaced to the right by d _max , L ₃ is displaced to the upper d
shows the space occupied at the time of d _max also displaced to the right as well as _max displacement. In the case of the spaces L ₁ and L ₂ , the cylindrical space for housing these movable parts is S
Although P ₁ is sufficient, if the correction optical system is displaced to the state of L ₃ , the cylindrical space is required up to SP ₃ .
That is, the lens barrel becomes thicker by the difference between the cylindrical spaces SP ₁ and SP ₃ .

On the other hand, the large displacement of the correction optical system described above causes a problem in terms of aberration.

That is, when designing the correction optical system, it is natural that aberration should be eliminated as much as possible, but in reality, the occurrence of aberration is unavoidable. Then, the aberration depends on the displacement of the correction optical system, and when it exceeds a certain allowable displacement, the aberration sharply increases.
On the other hand, if only normal camera shake occurs, the probability that a large displacement of the correction optical system as described above will occur during image blur correction is very small, but if a panning or framing changing operation is performed, the large displacement will occur. It may happen. If photography (exposure) is performed at this time, there arises a problem that a photograph with large aberration can be taken. In addition, when the shake correction possible range is excessively large, there arises a problem that operability at the time of changing panning or framing, that is, it takes a long time to restart the image shake correction after the end of panning.

In order to solve the above point, the applicant of the present invention has further filed Japanese Patent Application No. 3-254239.
In this application, when the displacement of the correction optical system by the two sets of drive means reaches a predetermined relationship, a means for limiting the drive displacement in these two directions is provided to solve the above problem. Specifically, when the operation range of the two axes is limited to a circle (FIG. 15) or an octagon (FIG. 16) and the correction optical system tries to operate beyond this range, it is detected. A control is added to temporarily stop what was being followed so as to cancel the blur.

[0010]

However, in the above proposal, when the operation range is limited to a circle, in order to judge whether or not it is within the operation range, the biaxial displacements dy and dp are determined.
It is necessary to calculate the sum of squares of (dy ² + dp ² ) and compare it with d _max ² .

[0011]

[Outer 1] Is compared with d _max , but the calculation of the square root can be omitted if d _max ² is stored in the ROM and used for comparison).

When the control for blur correction is performed by digital control, the time delay associated with the calculation affects the phase delay, and therefore the calculation must be completed in a short time as much as possible.
In a device-incorporated microcomputer that does not have a multiplier and can be used as a consumer product level, multiplication requires a longer calculation time than addition and comparison, and the above-described square sum calculation is a heavy burden.

When the operating range is limited to an octagon, dy and dp are compared with d _max , respectively, and dy
In the case of FIG. 16, it is only necessary to compare + dp with 1.5 × d _max, and the load as the calculation amount is low, but in the case of FIG. 16, the maximum error occurs at the apex as compared with the circle of FIG. The error reaches 11.8%. The error with the circle is minimized when the shape is a regular octagon, but there was a problem that the error was still 8.24% at the apex.

Further, in this method of judging whether or not it is within the operating range of the octagon, when it is within the operating range, it is inevitable that dp, d
It was necessary to compare y and dp + dy three times.

[0015]

According to the present invention, an image forming optical system, a correction optical mechanism for decentering or tilting the optical axis of the image forming optical system, and driving and connecting the correction optical mechanism. An image blur correction means for performing image blur correction on the image plane,
The correction optical mechanism is provided with two sets of driving means that are driven substantially independently of each other in two directions substantially orthogonal to each other, and the displacement detection means of the correction optical mechanism is provided on each of the axes in the two directions. When the output of the means reaches a predetermined relationship,
An image blur preventing device provided with a limiting means for limiting the displacement in these two directions, and intends to solve the above-mentioned problem by having data for the limitation as a table in two directions. Further, a better image blur prevention apparatus is provided by dividing the data of each axis of the table so as to minimize an error from a circle having a radius of a predetermined maximum operation range.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram showing the outline of a camera equipped with the apparatus of the 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 configuration of the camera body CMR side will be described.

The CCPU is a microcomputer in the camera (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, and the like in accordance with a camera sequence program stored in the ROM. Therefore, the in-camera microcomputer CCPU 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,
When power is supplied to the lens LNS via the power supply line VL, the output from the camera body CMR to the lens LNS via the signal line DCL and the lens body 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.

The SNS is a line sensor for focus detection (hereinafter simply referred to as a sensor) including a CCD and the like, and SDR is a drive circuit for driving the sensor SNS according to a command from the microcomputer CCPU in the camera. The image signal is taken in, amplified, and sent to the in-camera microcomputer CCPU.

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 its output signal is input to the camera microcomputer CCPU and used for automatic exposure control (AE) according to a predetermined program.

DDR is a switch detection and display circuit that 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 / off various operation members (SWMD) of the camera. The state is notified to the in-camera microcomputer CCPU 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 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 in-camera microcomputer CCPU, so that even if a program is being 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 motor, MTR2 is a motor for mirror up / down and shutter spring charging, and forward / reverse control is performed by respective drive circuits MDR1 and MDR2.

MG1 and MG2 are magnets for starting the leading and trailing shutter shutters, and amplifying transistors TR1 and T2.
Power is supplied at R2, and the shutter microcomputer STR controls the shutter STR.

Next, the structure of 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 function like the microcomputer CCPU in the camera. The microcomputer LCPU in the lens adjusts the focus adjustment lens FL according to the command sent from the camera body CNR via the signal line DCL.
NS drive control and diaphragm drive control are performed. It also signals 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.). It is transmitted to the camera side via the line DLC.

FMTR is a drive motor for the focus adjustment 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 of the motor FMTR, and controls forward / reverse rotation of the motor FMTR, braking, etc. according to a signal from the microcomputer LCPU in the lens.

This embodiment shows an example of the front focus type. When a focus adjustment command is sent from the camera body CMR, the motor FMTR is driven according to the driving amount and direction sent at the same time. Then, the focus adjustment lens FLNS is moved 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 counted by a counter in the lens microcomputer LCPU, and the motor FMTR is controlled when the predetermined movement is completed.

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. 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 adjustment lens FLNS, ENCZ is an encoder for detecting the zoom position, both of which are well-known methods such as a code pattern provided on the helicoid ring, the zoom ring and a detection brush. The detected signal 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 according to the number of aperture steps sent at the same time.
Drive the MTR.

The ICPU is an image blur correction microcomputer, which 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 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 image stabilization microcomputer IC
The PU takes the 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 the blur of the lens LNS, and is proposed by the applicant of the present invention, for example, Japanese Patent Laid-Open No.
A sensor utilizing the inertia of the fluid in the cylindrical case, such as the one disclosed in JP-86735, is used. The angular displacement output θ of the angular displacement meter is transmitted to the image blur correction microcomputer ICPU. Also,
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 to be described later, which 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 an input / output line.

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

The IACT is an image blur correction actuator provided in the support mechanism, which is composed of a magnetic circuit made of a permanent magnet 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, which 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 this position detection sensor PSD, so that the position detection sensor PSD causes the position of the incident light, that is, the correction optical meter 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.

FIG. 2 is a diagram showing the mechanical and electrical configuration of the angular displacement meter AD of FIG.

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

The basic structure of the angular displacement meter AD is almost the same as that proposed by the present applicant in Japanese Patent Application Laid-Open No. 4-86735. Here, the control circuit is slightly biased 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, the light projecting element 2 for optically detecting the movement of the floating body 22.
5 and the light receiving element 26 are arranged as shown in the figure, and further, the floating body 22 and the yoke 23 forming a closed magnetic circuit, and the winding coil 24 is arranged between the yoke 23 portion 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,
This is a basic configuration in which infrared light emitted from the light projecting element 25 is reflected by the floating body 22 by the position detecting 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, are differentially amplified by the operational amplifier 28, and are floated.
Is output, that is, the shake angle displacement (θ) of the lens barrel is output.

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 with the control lines SAD1 and SAD2, and is turned on (closed) when the line becomes high level. 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. 2 (b).

The portion C surrounded by the dotted line is the winding coil 24.
The operational amplifier 30 serves as a buffer in a driver unit for driving the. Therefore, a current corresponding to the output voltage of the control unit B flows through the winding coil 24. That is, since a 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 can be switched by the size of the switches SWAD1 and SWAD2. 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 startup time of the sensor when the power is turned on is shortened. And so on.

In FIG. 1, the image blur correction mechanism is shown for only one axis, but camera shake occurs in the two-dimensional directions of up, down, left, and right. Therefore, in an actual lens, the blur in the two axes is detected and the correction optical system is used. ILNS must also work two-dimensionally.

Therefore, FIG. 3 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 to correct camera shake in a plane orthogonal to the optical axis, thereby obtaining an image shake control effect on an 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 configuration is shown below.

In FIG. 3, 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 4.
6 is attached to the protrusion 46a. In addition, the fixed frame 4
A pitch coil 48p is attached to the unit 3. The pitch coil 48p includes a pitch magnet 49p and a pitch yoke 41.
The fixed frame 43 is placed in a magnetic circuit composed of 0p, and 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, and 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 detecting element PSD).

The above is the drive mechanism in the pitch direction.

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

The protrusions 46b and 46c on the holding frame 46 have P
A slide bearing 44y such as OM is mounted. On the other hand, the yaw slide shaft 45y is fixedly mounted on the protrusion 414a on the housing 414 attached to the lens barrel (not shown). Since the bearing 44y can slide on the shaft 45y, the holding frame 46 and the fixed frame 43 also move in the yaw direction (arrow 42y direction).
Can be moved to. The yaw coil 4 is attached to the fixed frame 43.
8y is provided, and the fixed frame 43 is driven also in the yaw direction 42y by the interaction between the yaw magnet 49y sandwiching the yaw coil and 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. Then, the pitch direction 4 of the correction lens 41
The driving in the 2p and the yaw direction 42y has the configuration shown in FIG.

The plane portion 43c provided at the lower left of the fixed frame 43 is restricted in position in the optical axis direction by a blurring-like 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-mentioned configuration.
This is because at least three position restricting parts (holding parts) are required in order to restrict the function of the fixed frame 43, which is two positions each for c, only in the shift direction. Therefore, two protrusions 50
The position of the flat 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. 4 shows the image blur correction control section in detail. The part surrounded by the dotted line corresponds to the image blur correction control circuit ICMT in FIG. The circuit ICNT, the angular displacement meter AD, and the like are provided for driving the pitch direction and yaw direction, respectively, and two are provided for each of the pitch direction element and the signal line, and y is for the yaw direction. The subscript of is added.
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 angular 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 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 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 at a low level, the control signal d is the circuit SH.
When the line SSH is at a high level, the control signal d at the time of reaching the high level is held and output continuously.

SWACT is a switch for turning on / off the control signal input to the actuator IACT, and 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 a voltage applied 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 moves 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
By inversely inputting _L to the addition point P1, a feedback loop with d as a control amount is formed, and the correction optical system I
The LNS is drive-controlled by the displacement corresponding to the control signal d.

The configuration of this embodiment has been described above. Next, the blur correction principle, that is, the relationship between the blur angle displacement (θ) and the lens drive amount (d _L ) and the image movement amount (displacement amount) d _IM will be described. . Assuming that the focal length of the photographic optical system ILNS is f and the photographic magnification is β, the photographic optical system is θ [ra about the front principal point.
The image displacement amount d _IM when the angle blur of [d] is generated is d _IM = f (1 + β) · θ (1). On the other hand, if the ratio of the displacement amount d _IM of the image to the displacement amount d _L of the correction optical system ILNS is referred to as the eccentricity sensitivity S _d , then d _IM = S _d · d _L (2) 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) (3). The principle of image blur correction is to eliminate the image blur (equation (1)) caused by the angular blur of the photographing optical system by the image displacement (equation (2)) caused by lens displacement. Therefore, (1) =
Using Equations (2) and (3), d = d _L = (d _IM / S _d ) = {f · (1 + β) · θ} / {S _d (f, β)} = kθ (4) or θ = {S _d (f, β) · d _L } / {f · (1 + β)} = d _L / k (5) is derived.

Similar to FIGS. 10, 12, and 13, FIG. 5 is a diagram for explaining the displacement of the correction optical system ILNS. The vertical axis is the vertical displacement for correcting pitch shake, and the horizontal axis is yaw shake. This is the displacement in the left-right direction, which corresponds to the directions of arrows 42p and 42y in FIG. 3, and is represented by d _p and d _y , respectively. In addition, the origin 0 in the range delimited by the stepped thick line
The side closer to is the movable range of the correction optical system ILNS.
As for the operable range, only the absolute value matters, so
In FIG. 5, only the first quadrant is shown.

Trajectories TR1, TR2 and TR3 are trajectories of the correction optical system ILNS during image blur correction in the present embodiment. When the image blur correction is started, the correction optical system ILNS
Starts to be driven from the origin 0 and is displaced like a locus TR1. Then, when the correction optical system ILNS reaches the boundary CR1 of this step-like movable range, in the present invention, the place which should originally be driven as the locus TR2 is controlled by stopping the driving during this period and waiting at the point P1. When the power displacement signal returns within the boundary CR1 of the step-like movable range, the correction optical system ILN
S moves from the point P1 to P2 and is controlled by the locus TR3 thereafter.

Next, the stepwise movable range will be described.

This movable range is a region set by approximating a circle of radius d _max , and in the present embodiment, it is determined by this approximation whether or not the correction optical system ILNS is within the movable range. Whether it is in the specified region, d _y ,
This is done by comparing d _p with a defined boundary value.

In this embodiment, the d _y direction and the d _p direction are each divided into 7, and the boundary point pairs (d _y 1, d _p 1) and (d _y
2, d _p 2), (d _y 3, d _p 3), (d _y 4, d _p
4), (d _y 5, d _p 5), (d _y 6, d _p 6), (d
_y 7 and d _p 7) are defined.

This boundary value data is the RO in the ICPU.
It is stored in M.

As described below, each boundary value is d _max
If it is decided that there is a certain relation from that, it is calculated by calculation, but in reality, ICPU
Since the full power is used for the calculation of the image blur prevention during the image blur prevention, the data calculated in advance for these boundary values is written in the ROM.

6 to 9 are views for explaining a method of determining the movable area of the correction optical system, and how to determine the boundary value of this area will be described below with reference to these drawings.

As a condition for selecting the boundary value, it is first necessary to reduce the data amount as much as possible.

For example, when the image blur prevention device is applied to the zoom lens, the maximum radius dmax at which the correction optical system can be moved changes depending on the zoom focal length. Therefore, there are many combinations of boundary values depending on the focal length. It becomes necessary to remember it. Therefore, it is important to reduce the amount of data as much as possible.

Therefore, first, the boundary is symmetrically set with respect to the line of dp = dy. Thereby, for example, (dy2, dp
2) = (dp6, dy6), and the data amount can be reduced to about half.

Therefore, first, (dy4, dp4) = d
Take it where the line of p = dy and the circle of radius dmax intersect.

At this time,

[0083]

[Outside 2] (Fig. 6).

Next, a method of determining (dy6, dp6) will be described with reference to FIG. As a condition, dmax
Is to reduce the error between and. (Dy
Among the areas delimited by 4, dp4) and (dy6, dp6), the points having the largest error are (dy4, dp6) and (dy6, 0). If the way of taking dy6 and dp6 is changed, one of the distances from the origin o of these two points becomes large but the other becomes small. Therefore, the distances from the origin o from these two points are set to be equal.

The distance from the origin o to the point (dy4, dp6) is

[0086]

[Outside 3] This is equal to dy6, so

[0087]

[Outside 4] By transforming this equation and substituting equation (6),

[0088]

[Outside 5] Moreover, it is dy6 ² + dp6 ² -dmax ² (9). From equation (8) and equation (9)

[0089]

[Outside 6] Becomes

Next, a method of determining (dy7, dp7) will be described with reference to FIG. As a condition, similar to the above, the error from dmax is set to be as small as possible. Among the areas delimited by (dy6, dp6) and (dy7, dp7), the point with the largest error is (dy6, d
p7) and (dy7,0). The distances from the origin o from these two points are set to be equal.

Similarly to the above,

[0092]

[Outside 7] By transforming this equation and substituting equation (10),

[0093]

[Outside 8] dy7 ² + dp7 ² = dmax ² (13) From equations (12) and (13),

[0094]

[Outside 9] Becomes

Next, a method of determining (dy5, dp5) will be described with reference to FIG. Similarly, the error from dmax is made as small as possible. (Dy4, dp4),
Among the areas delimited by (dy5, dp5) and (dy6, dp6), the point where the error is maximum is (dy4, dp
5) and (dy5, dp6). The distances from the origin o from these two points are set to be equal.

Assuming that the distances from the two points are equal,

[0097]

[Outside 10] By transforming this equation and substituting equations (6) and (10),

[0098]

[Outside 11] Further, dy5 ² + dp5 ² = dmax ² (17) From equations (16) and (17),

[0099]

[Outside 12] Becomes

The maximum error for the above points is equal for all points,

[0101]

[Outside 13] Is. It is 6.46% when expressed in percentage. this is,
It can be seen that the accuracy is higher than the error of 8.24% when the regular octagon is used as the region.

As described above, by taking the boundary symmetrically with respect to dp = dy, the above results in dp1 to dp3,
The values of dy1 to dy3 have also been obtained, and dp1 = d
y7, dp2 = dy6, dp3 = dy5, dy1 = dp
7, dy2 = dp6, dy3 = dp5.

In the ROM, dy4, dy5, dp5,
Only the values of dy6, dp6, dy7, dp7 are stored, and dy1, dp1, dy2, dp2, dy3, dp are stored.
When 3 and dp4 are required, other equal values are used. In the following description, in order to avoid complexity, dy1,
The symbols dp1, dy2, dp2, dy3, dp3 and dp4 will also be used.

10 and 11 are flowcharts showing the operation on the camera body side and the operation on the lens side in FIG. 1, respectively.

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.

First, the operation of the camera body CMR side 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 CPU in the camera is started, and after step (001), step (00)
The operation from 2) is started.

At step (002), the state of the switch SW1 which is turned on by pressing the release button in the first step is detected, and when SW1 is off, step (003).
Then, all the control flags and variables set in the RAM in the camera microcomputer CCPU are cleared and initialized, and the process proceeds to step (004). Step (00
In 4), the lens LNS side transmits a command to stop the image blur correction operation (IS).

The steps (002) to (004) are repeatedly executed until the switch SW1 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 uses exposure control (AE) and focus adjustment control (A
In the communication for obtaining the information required to perform F), 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 reads the ROM via the signal line DLC. The information such as the focal length, the AF sensitivity, the open F number, etc., stored therein is transmitted.

In step (012), a command for starting 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 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), an "exposure calculation" subroutine for obtaining the exposure control value is executed. In the subroutine, the apex arithmetic expression “Av + Tv = Bv +
Sv ”and a predetermined program diagram, shutter value T
v and aperture value Av are determined, and these are stored in a predetermined address of RAM.

In step (015), "image signal input"
Execute a subroutine. Here, the camera microcomputer C
The CPU 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 sub-routine flow of steps (015) and (016) is described in Japanese Patent Laid-Open No. 63-
Since it is disclosed in Japanese Patent No. 18314, the detailed description thereof will be omitted here.

In step (017), "lens drive"
Execute a subroutine. In the subroutine, only the drive pulse number of the focus adjustment lens FLNS calculated in step (016) on the camera body CMR side is transmitted to the in-lens microcomputer LCPU, and thereafter the in-lens microcomputer LCPU follows the predetermined acceleration / deceleration curve to the motor FMTR.
Drive control. After completion of driving, an end signal is transmitted to the microcomputer CCPU in the camera, this subroutine ends, and the process returns to step (002).

Next, the above step (01
A case will be described in which a release interrupt is input by turning on the switch SW2 during execution of each operation in the focus adjustment cycle shown in 5) to (017).

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, any step (02
It is configured to shift to 1).

When the switch SW2 interrupt is input 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. Then, in the next step (023), film winding is performed to end the photographing of one frame, and the step (00
Return to 2).

The steps (013) to (01)
The sub-routines of 7) and steps (022) and (023) are already known, and detailed description thereof will be omitted.

Next, the image blur correction operation performed on the lens LNS side will be described with reference to the flowchart of FIG. In each step, the subscript py is added to indicate that the operations in the pitch and yaw directions 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 stabilization microcomputer ICP
U starts executing the program after step (102) in FIG. In step (102), all flags and all variables in the image blur correction microcomputer ICPU are set to predetermined initial values (0 in most cases). 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 close to the origin at the start of image blur correction. I try to start from the state.

In step (104), the control line SS
The control displacement d _py is allowed to pass by setting H _py to the low level. In step (105), the image blur correction (IS) 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 is prohibited. Then, the process returns to step (103), and steps (103) to (106) are repeatedly executed. In this state, image blur correction is not performed.

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

At step (111), the control line SA
The DI _py 'SAD2 _py a low level, the angular displacement meter AD _py
Set the shake detection characteristics of to the camera shake correction compatible state. In step (112), the switch SWACT _py is turned on to start image blur correction.

At step (113), the encoder ENC for detecting the zoom ring position and the focus adjustment lens position.
ROM is detected from the output information by detecting the Z and ENCB states.
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.

Here, the eccentricity sensitivity S _d is expressed by the equation (2)
As described above, the ratio of the image displacement amount d _IM to the variable position d _L of the correction optical system ILNS is expressed as S _d = d _IM / d _L. The eccentricity sensitivity S _d is a function of the focal length f and the focus adjustment lens position, that is, the photographing magnification β. Therefore, the sensitivity S _d is the matrix data S _d (f,
β) is stored in the ROM as the encoder ENC
It is read from the ROM by the information of Z and ENCB.

Next, at step (114), the coefficient k for converting the blur angle θ in the above-mentioned equation (4) into the control displacement d of the correction optical system ILNS is calculated. Step (1
In 15), the shake angle displacement θ _P in the pitch direction is converted into the displacement control value d _P of the correction optical system ILNS and output to the input end of the sample hold circuit SH _P. Then step (11
In 6), the same operation as in step (115) is performed in the yaw direction.

Steps (117) and (118), and branching from these steps (122)
In steps (133) to (133), it is determined whether the correction optical system ILNS is within the operable range described above.

Here, first, the absolute values of dp and dy are respectively set to dp4 and dy4 (in the present embodiment, the magnitude is dp4 and dy4).
4 = dy4), dp and dy are dp4 and
If it is smaller than dy4, it is considered to be within the operable range and the process proceeds to the next step (119). If either is larger, it is compared with the next boundary value that has exceeded it, and if it is within that value, another corresponding By comparing with the value of the axis, it is judged whether or not it is within the operable range, and if it is larger than the next boundary value, it is further compared with the next boundary value. Repeat the steps.

First, in step (117), the absolute value of the pitch direction displacement dp of the correction optical system ILNS is compared with the boundary value data dp4 (since dp4 = dy4, it is actually compared with the data of dy4 in the ROM). In the following, if there are other equal values in the ROM as well, the other values will be used for comparison but will be complicated, and the description will be omitted). If | dp | <dp4, then step (11
8), and if | dp | ≧ dp4, go to step (1
Proceed to 22).

At step (122), | dp | is compared with dp3. If | dp | <dp3, the process proceeds to step (125), and if | dp | ≧ dp3, the process proceeds to step (123). In step (125), the yaw direction boundary value dy3 corresponding to dp3 is compared with the yaw direction absolute value | dy | of the correction optical system displacement. ｜
If dy | <dy3, it is within the operable range, so the process proceeds to step (119). If | dy | ≧ dy3, it is outside the operable range, so the process proceeds to step (134).

In step (123), | dp | is compared with dp2. If | dp | <dp2, the process proceeds to step (126), and if | dp | ≧ dp2, the process proceeds to step (124). In step (126), the yaw direction boundary values dy2 and | dy corresponding to dp2
Compare with |. If | dy | <dy2, it is within the operable range, so the process proceeds to step (119), and | d
If y | ≧ dy2, it is out of the operable range, so the process proceeds to step (134).

At step (124), | dp | is compared with dp1. If | dp | <dp1, the process proceeds to step (127), and if | dp | ≧ dp1, it is out of the operable range, so the process proceeds to step (134).
In step (127), the boundary value dy1 in the yaw direction corresponding to dp1 is compared with | dy |. ｜ dy ｜
If <dy1, it is within the operable range, so the process proceeds to step (119), and if | dy | ≧ dy1,
Since it is out of the operable range, the process proceeds to step (134).

At step (117), | dp | <
In the case of dp4, the process proceeds to step (118). In step (118), the absolute value of the displacement dy in the yaw direction of the correction optical system ILNS is compared with the boundary value data dy4. ｜
If dy | <dy4, it is in the operable range, so the process proceeds to step (119). If | dy | ≧ dy4, the process proceeds to step (128).

In step (128), | dy | is compared with dy5. When | dy | <dy5, the process proceeds to step (131), and when | dy | ≧ dy5, the process proceeds to step (129). In step (131), the boundary value dp5 in the pitch direction corresponding to dy5 is compared with the absolute value | dp | in the pitch direction of the correction optical system displacement. If | dp | <dp5, it is within the operable range, so the process proceeds to step (119) and | dp | ≧ dp5.
In the case of, since it is out of the operable range, step (134)
Proceed to.

At step (129), | dy | is compared with dy6. If | dy | <dy6, the process proceeds to step (132). If | dy | ≧ dy6, the process proceeds to step (130). In step (132), the boundary values dp6 and | d in the pitch direction corresponding to dy6
Compare with p |. If | dp | <dp6, it is within the operable range, so the process proceeds to step (119), and |
If dp | ≧ dp6, it is out of the operable range, so the process proceeds to step (134).

In step (130), | dy | is then compared with dy7. If | dy | <dy7, the process proceeds to step (133), and if | dy | ≧ dy7, it is out of the operable range, so the process proceeds to step (134).
In step (133), the boundary value dp7 in the pitch direction corresponding to dy7 is compared with | dp |. ｜ dp
If | <dy7, it is within the operable range, so the process proceeds to step (119), and if | dp | ≧ dp7,
Since it is out of the operable range, the process proceeds to step (134).

If it is determined from the above arm determination step within the operable range that the arm is within the operable range, the process proceeds to step (119) to continue the image blur correction.
In step (119), control lines SSHp and S
SHy is set to low level, and the sample hold circuit SHp
And SHy are deactivated and pass signals dp and dy. In step (120), the control line SAD1
y and SAD1y are set to low level, and the angular displacement meter ADp
Then, the blur detection characteristics of ADy and ADy are brought into a state suitable for camera shake correction. That is, in steps (119) and (120), a normal image blur correction operation is performed.

On the other hand, if it is determined that the control line is out of the operable range, the process proceeds to step (134), and in this step (134) the control lines SSHp and SS
Hy is set to a high level. Then, the outputs of the sample hold circuits SHp and SHy are fixed to the input values at that time. Therefore, the displacement of the correction optical system ILNS remains fixed at the point P1 on the boundary CR1 of the operable range in FIG. 5, and the image blur correction is interrupted.

In step (135), the control line SA
With D1p and SAD1y set to high level, angular displacement meter A
High-pass characteristics are given to Dp and ADy, and their output signals dp and dy quickly return to zero, which helps restart the image blur correction.

After executing step (120) or (135), the process proceeds to step (121).

At step (121), the camera body CM
It is determined whether or not the IS stop command is received from R, and if not received, the process returns to step (113), and the flow of steps (113) to (135) is executed.

Step (117) during execution of the above flow
When the correction optical system returns to the operable range in steps (133) to (133), step (119),
The flow of (120) is executed, and the normal image blur correction is restarted. At this time, the displacement of the correction optical system ILNS rapidly moves from point P1 to point P2 in FIG.
Image blur correction is performed according to 3.

In step (123), the camera body C
Recognizing that the MR has sent an IS stop command,
Returning to step (103), the image blur correction is stopped at step (106).

Steps (113) to (135)
Is repeatedly performed in a cycle of about several msec, so that the camera shake having a band of about 1 to 10 Hz can be sufficiently corrected.

(Other Embodiments) FIG. 12 is a diagram showing the operating range of the correction optical system according to the second embodiment of the present invention.

In the first embodiment, the operating range is d
The shape is inscribed in a circle having a radius dmax so as not to exceed max, but in this embodiment, the boundary is set so as to circumscribe this circle. The boundary values are the values of dy1 to dy7 and dp1 to dp7 obtained in the first embodiment.

[0149]

[Outside 14] It is calculated by dividing by. The maximum value of the error at this time is

[0150]

[Outside 15] Which is the reciprocal of 6.90%, and the accuracy is higher than when a circumscribing regular octagon is used.

Further, in the present invention, a means for dividing one quadrant into seven per axis is shown in consideration of the amount of data and the calculation time, but it goes without saying that the number of divisions is not limited to this. .

For example, if a boundary point is obtained in the middle of each boundary obtained in the first embodiment by the same method as in the first embodiment, each axis is divided into 15 (the data amount may be 8 points). .

The maximum error at this time is

[0154]

[Outside 16] Thus, a higher accuracy of 3.18% in percentage is obtained.

[0155]

As described above, according to the present invention,
By approximating the operating range of the correction optical system into a circle by dividing the area and comparing the data of this boundary with the coordinates of the correction optical system, it can be quickly determined whether or not it is within the operating range.

Further, in order to determine the boundary so that the error with the circle is minimized, an octagon is used to approximate a circle.
High accuracy for circles even with a small amount of data.

When an octagon is used, the comparison operation must be performed 3 times even if it is in the area, but in the present invention, it is at least 2 times in the area near the origin. It has an excellent effect.

[Brief description of drawings]

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

FIG. 2 is a diagram showing a mechanical and electrical configuration of the angular displacement meter according to the first embodiment of the present invention.

FIG. 3 is a perspective view showing a correction optical mechanism in the first embodiment of the invention.

FIG. 4 is a block diagram showing an image blur correction control circuit according to the first embodiment of the present invention.

FIG. 5 is a diagram for explaining the operation of the first embodiment of the present invention.

FIG. 6 illustrates a method of determining a boundary of a movable area of the correction optical system according to the first embodiment of this invention.

FIG. 7 illustrates a method of determining a boundary of a movable area of the correction optical system according to the first embodiment of the present invention.

FIG. 8 illustrates a method of determining a boundary of a movable area of the correction optical system according to the first embodiment of the present invention.

FIG. 9 illustrates a method of determining a boundary of a movable area of the correction optical system according to the first embodiment of the present invention.

FIG. 10 is a flowchart showing an operation on the main body side of a camera provided with the first embodiment device of the present invention.

FIG. 11 is a flowchart showing an image blurring operation on the lens side including the apparatus according to the first embodiment of the present invention.

FIG. 12 is a diagram showing a movable area of a correction optical system according to a second embodiment of the present invention.

FIG. 13 is a diagram for explaining a displaceable range of a correction optical system in a conventional device of this type.

FIG. 14 is a diagram for explaining an operation range of a correction optical system in a conventional device of this type.

FIG. 15 is a diagram for explaining a movable range of a correction optical system in another conventional device of this type.

FIG. 16 is a diagram for explaining a displaceable range of a correction optical system in another conventional device of this type.

[Explanation of symbols]

 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

Claims (2)

[Claims] 1. An image forming optical system, a correction optical mechanism for decentering or tilting an optical axis of the image forming optical system, and an image blur correction for driving the correction optical mechanism to perform image blur correction on an image forming plane. The correction optical mechanism is provided with two sets of driving means that are driven substantially independently of each other in two directions substantially orthogonal to each other, and the displacement detecting means of the correction optical mechanism is provided on each of the axes in the two directions. An image blurring device provided with limiting means for limiting the displacement in these two directions when the output of the displacement detecting means in the two directions reaches a predetermined relationship, wherein the data for the limitation is converted into a two-way table. An image blur prevention device characterized by having. 2. The image blur prevention device according to claim 1, wherein the data of each axis of the table is divided so as to minimize an error from a circle having a radius of a predetermined maximum operation range. .