JP3181904B2 - Image blur prevention device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image blur prevention device for preventing an image blur occurring in a camera, an optical device, or the like.

BACKGROUND OF THE INVENTION Conventionally, various apparatuses for correcting camera shake have been proposed, for example, Japanese Patent Application Laid-Open No. 63-49729.

In these methods, in order to prevent blurring of an image on an image plane caused by camera vibration, a method of moving the optical axis decentering means to be controlled by a feedback control mechanism to suppress image blurring is adopted. Have been.

For example, a camera shake vibration (usually a tilt vibration of the camera with respect to the photographing optical axis) is detected as an acceleration signal, and the acceleration signal is integrated by a signal processing system to obtain a speed signal (and a displacement signal). The optical axis decentering means is driven in a vibration suppressing direction (a direction in which apparent vibration of an image is suppressed).

FIG. 14 shows an example of the principle configuration of an image blur correction apparatus including such a signal processing system. In FIG. 14, reference numeral 1 denotes an accelerometer, which corresponds to a photographing optical axis of a camera (not shown). The tilt is detected as an acceleration signal. The detected acceleration signal a is integrated into a speed signal v by a first integrator 2 and further converted into a displacement signal d by a second integrator 3.

Numeral 5 denotes an actuator for moving the optical axis decentering means 4 (usually an imaging lens system) of the camera which is provided so as to be movable in the radial direction in order to prevent image blur in the radial direction by inputting the displacement signal d. It operates to drive control.

Reference numeral 6 denotes a position detecting sensor which constitutes a position detecting means for detecting an actual position displacement of the optical axis eccentric means 4, and a signal from the position detecting sensor 6 is supplied to an input system of the actuator 5 via an operational amplifier 7. The feedback loop is configured to provide feedback so that the drive control of the optical axis eccentric means 4 corresponds to the vibration displacement.

Here, if the drive range of the optical axis eccentric means 4 is smaller than the camera shake displacement amplitude, the optical axis eccentric means 4 will use up its displacement stroke when performing the image blur correction operation. No correction is made. Therefore, if this stroke exhaustion occurs frequently, the photographer hardly recognizes the blur correction effect. Therefore, conventionally, it is general that the drivable range of the optical axis eccentric means 4 is configured to have a sufficient amount to correct a normal camera shake vibration.

However, as the driveable range of the optical axis eccentric means 4 is increased, the following problem occurs.

1) Depending on the method of supporting the optical axis eccentric means 4, when the optical axis eccentric means is displaced in a direction perpendicular to the optical axis, the displacement occurs in the optical axis direction, albeit minutely.

2) As the displacement of the optical axis eccentric means 4 increases, the amount of various aberrations increases.

In other words, in order to improve the image blur correction ability, it is preferable that the drive range of the optical axis eccentric means 4 is large. Even if the correction is made well,
The result is out-of-focus or large-aberration photographs, making it impossible to obtain high-quality photographs.

(Object of the Invention) The present invention has been made in view of the above-mentioned circumstances, and is an image blur prevention method capable of preventing an image from being taken in a state where image blur prevention is not properly performed. It is intended to provide a device.

(Features of the Invention) In order to achieve the above object, according to the present invention, a movable means for preventing image blur and an operation performed prior to an operation for causing a camera to perform a shooting operation are provided. An operation control means for starting the operation of the movable means, and a signal corresponding to a displacement of the movable means is determined in accordance with an operation for causing a camera to perform a shooting operation while the movable means is operating. And a prohibition means for prohibiting camera exposure in response to the determination means determining that a signal corresponding to the displacement has a value indicating a value greater than a predetermined displacement. Device.

The present invention according to claim 2, wherein the prohibiting means determines that the exposure means determines that the signal corresponding to the displacement has a value indicating that the signal is smaller than a predetermined displacement. An image blur prevention apparatus according to claim 1 for canceling the prohibition.

Furthermore, in the present invention according to claim 3, the operation control means causes the movable means to perform a centering operation toward a center position of an operation range after the exposure is prohibited by the prohibition means. This is an image blur prevention device.

Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

FIGS. 1 to 9 show a first embodiment of the present invention, and FIG. 1 is a diagram showing a main part according to the present invention.

In FIG. 1, CMR represents a camera body, and LNS represents a detachable interchangeable lens.

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

The CCPU is a microcomputer in the camera (hereinafter, referred to as a microcomputer), and is a one-chip microcomputer having a ROM, a RAM, and an A / D conversion function. The microcomputer CCPU in the camera performs a series of camera operations such as automatic exposure control, automatic focus adjustment, and film winding according to the camera sequence program stored in the ROM. For this purpose, the 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, and the power supply line VL
Supply power to the lens LNS and the camera body CMR
An inter-lens communication buffer for the output from the lens to the lens LNS via the signal line DCL and the output from the lens LNS to the camera body CMR via the signal line DLC.

SNS is a focus detection line sensor (hereinafter simply referred to as a sensor) composed of a CCD, etc., and SDR is its drive circuit, which drives the sensor SNS according to the instruction of the microcomputer CCPU in the camera.
The image signal from the sensor SNS is taken in, amplified, and sent to the microcomputer CCPU in the camera.

Light from lens LNS is main mirror MM, focus glass P
G, enters the photometric sensor SPC via the pentaprism PP,
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 that switches the display of the camera's display member DSP based on data sent from the camera's microcomputer CCPU and communicates the on / off state of various camera operation members inside the camera by communication. Notify the microcomputer CCPU.

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

MTR1 is a motor for film feeding, MTR2 mirror up / down and shutter spring charging, and the forward and reverse rotations are controlled by respective drive circuits MDR1 and MDR2.

MG1 and MG2 are shutter start curtain and rear curtain running start magnets, respectively, which are energized by amplification transistors TR1 and TR2, and are controlled by a microcomputer CCPU in the camera.

 Next, the configuration 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 performs drive control of the focus adjustment lens FLNS and drive control of the diaphragm in accordance with a command sent from the camera body CMR via the signal line DCL.
In addition, various operation states of the lens (how much the focus adjustment optical system has been driven, how many stops have been stopped, etc.) and parameters (open F number, focal length, coefficients of defocus amount vs. extension amount, etc.) are signaled. Send to camera via line DLC.

FMTR is a drive motor for the focus adjustment lens FLNS, which rotates a helicoid ring (not shown) via a gear train,
The focus is adjusted by moving the FLNS back and forth in the optical axis direction.

FDR is a drive circuit of the motor FMTR, and controls forward / reverse rotation, brake, and the like of the motor FMTR in accordance with a signal from the microcomputer LCPU in the lens.

This embodiment shows an example of an inner focus type. When a focus adjustment command is sent from the camera body CMR, the motor FMTR is driven according to the drive amount and direction sent at the same time, and the focus is adjusted. The focus is adjusted by moving the adjustment lens FLNS in the optical axis direction. The focusing lens
The movement amount of the FLNS is monitored by a pulse signal of the encoder circuit ENCF and is counted by a counter in the microcomputer LCPU in the lens. When the predetermined movement is completed, the motor FMTR is controlled.

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

When an aperture control command is sent from the camera body CMR, a known stepping motor DMTR for driving an aperture is driven in accordance with the number of aperture stages sent at the same time.

The ICPU is an image stabilization microcomputer that controls the image stabilization operation and controls the signal DCL and lens LN from the camera body CMR to the lens LNS.
The signal DLC from the S to the camera body CMR is input, 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 microcomputer ICPU
Takes the form of intercepting the communication between the two. Communication from the image blur correction microcomputer ICPU to the camera microcomputer CCPU is performed via the lens microcomputer LCPU.

ACC is an accelerometer (angular accelerometer, to be precise) for detecting the shake of the lens, and sends an (angular) acceleration signal a to the integrator INT1. The integrator INT1 integrates the (angular) acceleration signal a and converts the (angular) velocity signal v to an image blur correction microcomputer ICPU and an integrator.
Send to INT2. The integrator INT2 integrates the (angular) velocity signal v, sends out the (angular) displacement signal d to the image blur correction microcomputer ICPU, and sends it to the positive input terminal of the operational amplifier AMP. On the other hand, if necessary, the integrators INT1 and IN1
The output of T2 can be reset to "0".

The ILNS is a correction optical system that is an optical axis decentering means, is supported by a link mechanism described later, and can move substantially parallel to a plane perpendicular to the optical axis.

IMTR is an image blur correction motor that rotates the cam CAM fixed on the motor shaft forward and backward to displace the correction optical system ILNS.

IDR is a drive circuit of the image blur correction motor IMTR. The output signal from the operational amplifier AMP controls the motor IMTR to be positive or negative.
Drive in reverse.

PSD is a position detection sensor of the correction optical system ILNS, and light from the infrared light emitting diode IRED passes through a 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. The position detection sensor PSD generates a position of the incident light, that is, a position signal dL of the correction optical system ILNS. And this output signal (dL) is the microcomputer for image blur correction
The signal is input to the minus input terminals of the ICPU and the operational amplifier AMP.

SWIS is a main switch of the image blur correction operation circuit. When the switch SWIS is turned on, power is supplied to the microcomputer ICPU for image blur correction and its peripheral circuits, and then a reset signal RS
1, the integrators INT1 and INT2 are reset by RS2, and the shake signal is initialized. When the switch SW1 of the camera body CMR is turned on, this signal is sent to the microcomputer LCP in the lens.
The image blur correction microcomputer ICPU is communicated via U, and the motor IMTR is driven to start the image blur correction operation.

Although dL is assumed to be the position signal of the correction optical system ILNS, since the displacement of the correction optical system ILNS and the amount of optical axis eccentricity caused by this are proportional, dL may be regarded as the amount of optical axis eccentricity. No problem. The origin of this signal is a position where the central axis of the correction optical system ILNS coincides with the photographing optical axis.

In FIG. 1, the image blur correction mechanism is shown for only one axis, but since camera shake occurs in two-dimensional directions (up, down, left, and right), an actual lens detects blur in the two axes, and the correction optical system IL.
NS must also move in two dimensions.

FIG. 2 shows the support mechanism of the correction optical system ILNS in detail, and is a perspective view seen obliquely from the front on a horizontal plane including the optical axis. Normally, the blur is decomposed into two axes of a vertical direction (pitch) and a horizontal direction (yaw) to perform detection and blur correction, but in the present embodiment, in the I and J directions inclined at 45 ° with respect to the two directions. The reference axis for blur correction is set.

In FIG. 2, an arrow G indicates the direction of gravity, and 1i and 1J indicate angular accelerometers for detecting angular shake of the photographing optical axis C in the directions I and J, and correspond to ACC in FIG. The shake, that is, the angular acceleration ai is detected by the angular accelerometer 1i, and the shake in the J direction, that is, the angular acceleration aj, is detected by the angular accelerometer 1j. 31 is a fixed frame fixed to the taking lens body, 37 is a moving frame, plates 35 and 36
And it is connected to the fixed frame 31 by flexible tongues 34, 38 to 40, and is movable in the direction of arrow di. Reference numeral 32 denotes a lens holding frame, which holds a correction optical system 33 (this corresponds to the ILNS in FIG. 1), and has a moving frame 37 formed by plates 41 and 42 and flexible tongues 43 to 46.
And is movable in the direction of arrow dj with respect to the moving frame 37.

Reference numeral 51 denotes a di-direction driving motor, which corresponds to the IMTR in FIG. 1 and is fixed to the flat portion 31i of the fixed frame 31 via the motor base 47.
A cam 52 (which corresponds to CAM in FIG. 1) and a pulley 53 are fixed to an output shaft 51a of the motor 51.
a comes in contact with the cam follower 54 attached to the mobile 37,
By the rotation of the motor shaft 51a and the cam 52, the moving frame 37 is moved in the di direction. One end of a spring 56 is connected to the distal end of the wire 55 wound around the pulley 53, and the other end is hung on a spring hook 57 implanted in the moving frame 37, so that a contact between the cam 52 and the cam follower 54 is provided. The contact force F works. The reason for using the pulley 53 and the wire 55 to generate the contact force is to prevent the torque from being generated in the cam 52 by the corresponding contact force, and the detailed mechanism has been previously applied by the present applicant. Omitted.

Reference numeral 58 denotes a slit plate fixed to the moving frame 37.
Infrared light emitting diode (equivalent to IRED in Fig. 1)
A moving frame 37 is formed by a known method using a position detection sensor 59 (corresponding to the PSD in FIG. 1) 60 and a slit 58a of a slit plate 58.
To detect the position in the di direction.

Reference numeral 61 denotes a motor that drives the lens holding frame 32 in the dj direction, and is fixed to the flat portion 31j of the fixed frame 31 via the motor base 48.
A cam 62 and a pulley 63 are similarly fixed to the motor shaft 61a, and the cam 62 and the cam follower 64 are abutted by a wire 65, a spring 66, and a spring hook 67. Here, the cam follower 64 is provided not on the lens holding frame 32 but on the intermediate lever 71. The intermediate lever 71 is fixed to the fixed frame 31 via the flexible tongue 72.
, And swingable in the direction of the arrow θj. Intermediate bearings 73 and 74 are mounted on the lever 71, and the bearing is in contact with the flat portion 32 j of the lens holding frame 32. Therefore, the cam follower 64,
The intermediate lever 71 and the intermediate bearings 73 and 74 are integrally displaced in the θj direction, which causes the lens holding frame 32 to move in the dj direction. Since the displacement of the moving frame 37 in the di direction is absorbed between the flat portion 32j of the lens holding frame 32 and the intermediate bearings 73 and 74, interference between the movement in the di direction and the movement in the dj direction is avoided. A slit plate 68 is fixed to the lens holding frame 32, and the infrared light emitting diode 69 and the position detection sensor PSD7 are provided.
By 0, the displacement of the lens holding frame 32 in the dj direction is detected.

With the above configuration, the angular displacement of the lens in the I direction can be measured.
1i, the moving frame 37 and the lens holding frame 32 are driven in the di direction by driving the motor 51 based on the blur signal, and the blur in the J direction is detected by the angular accelerometer 1j. , The lens holding frame 32 is driven in the dj direction via the intermediate lever 71. Then, by these two-axis direction blur correction operations, two-dimensional blur on the shooting screen can be corrected.

Now, the moving trajectory of the moving frame 37 will be described in more detail.

Although it has been described that the moving frame 37 moves in the direction of arrow di, strictly speaking, it draws an arc-shaped locus whose radius is the length 1 of the blades 35 and 36. This is shown in FIG. The bird's-eye view direction in this figure is the same as that in FIG.

First, the movement of the moving frame 37 in the direction of the arrow di is precisely the arc A
The movement is i '. Therefore, the movement of the moving frame 37 along the arc Ai 'is a movement along the arc Ai in the correction optical system 33. In other words, when trying to move in the direction of the arrow di, when the origin is on the optical axis, as the absolute value of the displacement in the di direction increases, the correction optical system 33 will compete forward on the optical axis. . Similarly, when trying to move the correction optical system 33 in the dj direction by the motor 61, the trajectory becomes an arc Aj, and as the absolute value of the displacement in the dj direction increases, the correction optical system 33 retreats to the trouble of the film. .

That is, when the center axis of the correction optical system 33 is located at a position deviated from the photographing optical axis, a slight movement also occurs in the optical axis direction, and the amount thereof is obtained by combining the displacement amounts of the arcs Ai and Aj in the optical axis direction. Becomes

 This will be further described in detail with reference to FIG.

FIG. 4 shows the amount of change δ of focus with respect to the optical axis eccentricity dL by contour lines, and is a view of the optical system shown in FIG. 2 as seen from the rear side of the lens barrel, that is, from the right side in FIG.

In general, the correction optical system 33 for performing the optical axis decentering action has an imaging power, and when the correction optical system 33 is displaced in the direction perpendicular to the optical axis, the optical axis is decentered and Shift the image (this is the principle of image blur correction). On the other hand, when the correction optical system 33 moves in the optical axis direction, the image forming position moves in the optical axis direction. Therefore, in this embodiment, for simplicity of description, the shift amount of the correction optical system 33 in the vertical direction of the optical axis = the shift amount of the image = dL The shift amount of the correction optical system 33 in the optical axis direction = the focus shift amount = δ. FIG. 4 shows the relationship between dL and δ.

In FIG. 4, the di direction is the i axis, the dj direction is the j axis, the horizontal direction is the x axis, and the vertical direction is the y axis. The movable range of the correction optical system 33 in the i and j axis directions is ± dmax.

Here, as described in FIG. 3, when the correction optical system 33 is displaced in the i direction (either positive or negative), a very small amount moves in the optical axis direction toward the front of the photographing optical axis, that is, in FIG. Moving. At this time, the sign of the minute movement amount δ is negative. on the other hand,
In the displacement in the j direction, the paper moves to this side, and the sign of δ at this time is positive. Plate 35,36,41,4 in Fig. 2
If the lengths 2 are all the same, if the correction optical system 33 is displaced in the x direction (both positive and negative) or in the y direction (both positive and negative), the movement in the optical axis direction is canceled. To “0”.

That is, as shown in FIG. 4, on the x and y axes, the displacement δ in the optical axis direction is “0”, and when the displacement absolute value in the i direction increases, δ increases in the negative direction and the displacement absolute value in the j direction increases. Then, δ increases in the positive direction, and the contour line of δ becomes hyperbolic as shown (unit of δ is mm).

There is no problem if the focus shift amount δ is within the depth of focus of the lens, but if it exceeds the depth of focus, the photograph will be out of focus. Therefore, in the present invention, the lens displacement
If dL exceeds a lens displacement (± dcr) that generates an allowable out-of-focus amount (for example, δ = ± 0.1 mm), release is prohibited, and an out-of-focus photograph is prevented.

The operation of the camera and lens having the above configuration will be described with reference to flowcharts.

When a power switch (not shown) of the camera body CMR is turned on, power supply to the microcomputer CCPU in the camera is started, and the microcomputer CCPU in the camera starts executing a sequence program stored in the ROM.

FIG. 5 is a flowchart showing the entire flow of the program on the camera body CMR side.

When the execution of the program is started by the above operation, the state of the switch SW1 which is turned on by pressing the release button in the first step is detected in step (002) through step (001), and to (003) when the switch is off. Then, all the control flags and variables set in the RAM of the microcomputer CCPU in the camera are cleared and initialized.

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

The above 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 moves from step (002) to (011).

In step (011), lens communication 1 is performed. This communication is for obtaining information necessary for performing exposure control (AE) and focus adjustment control (AF). When the microcomputer CCPU in the camera sends a communication command to the microcomputer LCPU in the lens via the signal line DCL The microcomputer LCPU in the lens is a signal line DLC
, Information such as the focal length, the AF sensitivity, and the open F number stored in the ROM.

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

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

In step (014), an "exposure calculation" subroutine for obtaining an exposure control value is executed. In this subroutine,
According to the Apex calculation formula “Av + Tv = Bv + Sv” and a predetermined program diagram, determine the shutter value Tv and the aperture value Av,
These are stored in a predetermined address of the RAM.

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

Subsequently, 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) has been disclosed by the present applicant in Japanese Patent Application Laid-Open No. 63-18314, and a detailed description thereof will be omitted.

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

Next, the above steps (015) to (017) surrounded by a broken line
The following describes a case where a release interrupt is generated by turning on the switch SW2 during execution of each operation in the focus adjustment cycle shown in FIG.

The switch SW2 is connected to the microcomputer CCP in the camera as described above.
The switch is connected to the interrupt input terminal of U, and when the switch SW2 is turned on, the process immediately shifts to step (021) by the interrupt function regardless of which step is being executed.

If a switch SW2 interrupt is input during execution of the step enclosed by the broken line, the release prohibition timer RTIME is executed at step (022).
Reset R (initialize to 0). This timer RTIMER
A self-running timer means incorporated in the microcomputer CCPU in the camera measures the time of the release prohibition operation after the interruption of the switch SW2 as described later.

In “lens communication 2” of step (023), position information of the correction optical system ILNS during the image blur correction operation is received.

First, when the microcomputer CCPU in the camera sends an ON signal of the switch SW2 to the lens LNS side, the microcomputer I
The CPU receives this, and determines the position of the ILNS at that time, that is, the position signal from the position detection sensor PSD. This determination is a determination as to whether or not the focus movement generated according to the displacement of the correction optical system ILNS is allowable as described above. When the optical characteristics of the correction optical system ILNS and the support structure of the correction optical system ILNS are determined, the focus movement amount is a function of only the displacement dL of the correction optical system ILNS. Assuming that the displacement of the system ILNS is dcr, | dL | and dcr
It can be determined whether or not the out-of-focus state can be tolerated based on the magnitude relationship. Therefore, the image blur correction microcomputer ICPU sets the flag LFLG to "0" when the displacement is acceptable, and sets it to "1" when the displacement is not acceptable.
This is transmitted to the LCPU, and the microcomputer LCPU in the lens transmits this to the microcomputer CCPU in the camera. The setting of the flag LFLG will be described with reference to the flow of FIG.

In step (024), the magnitude of the aperture control value Av and the focus deviation allowable aperture value Avcr are determined, and it is determined whether or not the release is unconditional.

The maximum amount of defocus is determined by the optical characteristics of the correction optical system ILNS,
It depends on the support method and the maximum displacement. In this embodiment, it is assumed that the maximum defocus amount is ± 0.15 mm. On the other hand, when the aperture value is F4, the depth of focus is about ± 0.15 mm. Therefore, when the aperture control value is smaller than this, even if the displacement of the correction optical system ILNS is the maximum, defocusing can be tolerated. Therefore, the aperture value Av = 4 in the apex calculation equation corresponding to F4
Is set to Avcr, if the aperture control value Av is Av ≧ Avcr (= 4), it is determined that the focus shift is always allowable, and the step (02)
Move to 7) and release operation. On the other hand, when Av <Avcr, there is a possibility that a focus shift exceeding an allowable value may occur depending on the position of the correction optical system ILNS. Therefore, the process proceeds to step (025).

In step (025), the flag LFLG relating to the position of the correction optical system ILNS is determined. That is, when LFLG = 0, it is determined that the camera is at a position where the out-of-focus state can be tolerated, and the process proceeds to the release operation from step (027). If LFLG = 1, that is, if LFLG ≠ 0, it is determined that there is a risk of out-of-focus, and the flow shifts to step (026) to suspend the release operation.

In step (026), timer RTIMER in step (022)
The elapsed time from the time of resetting, the comparison between the upper limit value T _O of the release start waiting performing. If RTIMER <T ₀ , the process returns to step (023) and repeats steps (023) to (025) to correct the optical system ILNS by the blur correction.
As a result of step (02), step (02) is performed until LFLG = 0, that is, the correction optical system ILNS enters the predetermined area and the focus shift is allowable.
3) to (026) are repeatedly executed. And LF within time T ₀
If LG = 0 does not hold, RTIMER in step (026)
≧ T _O is determined YES, and to communicate the release cancel signal to the lens in step (029), the flow returns to step (002) without release.

In step (027), a "release" subroutine is executed. The flow of this subroutine will be described with reference to FIG.

 In step (028), film winding is performed.

The photographing for one frame is completed by the above steps, and the process returns to step (002).

Next, the "release" subroutine will be described with reference to FIG.

The mirror of the main mirror MM is raised in step (102) through step (101). This is executed by controlling the motor MTR2 via the drive circuit MDR2 shown in FIG.

In the next step (103), the step shown in FIG.
The aperture control value already stored in the "exposure calculation" subroutine of 13) is sent to the lens LNS side to perform aperture control.

In step (104), the previous steps (102) and (103)
It is determined whether or not the mirror-up and the aperture control have already been completed. The mirror up can be confirmed by a detection switch (not shown) attached to the main mirror MM, and the aperture control confirms by communication whether or not the lens has been driven to a predetermined aperture value. If any of them is not completed, the process waits at this step and continues to detect the state. When both controls are confirmed, the process proceeds to step (105). At this point, the preparation for exposure is complete.

In step (105), the shutter is controlled with the shutter control value already stored in the "exposure calculation" subroutine in the previous step (013), and the film is exposed.

When the control of the shutter is completed, in the next step (106), a command is sent to the lens LNS to open the aperture, and then the mirror is lowered in step (107). Mirror down is the same drive circuit as mirror up
This is executed by controlling the motor MTR2 via the MDR2.

In the next step (108), similarly to step (104), the control waits for the mirror down and aperture opening control to be completed. When both mirror down and aperture opening control are completed, step (10
Go to 9) and return.

Next, an image blur correction operation performed on the lens LNS side will be described with reference to the flowchart of FIG.

In step (201), the image blur correction main switch SWI
When S is turned on, a military source is supplied to the image blur correction microcomputer ICPU and its peripheral circuits.

In step (202), the two integrators INT1 and INT2 are reset, and their outputs v and d are initialized to "0".

In step (203), an IS start command is determined. If no IS start command is received from the camera body CMR, step (2) is performed.
03). In this state, the image blur correction is not performed, but the accelerometer ACC and the two integrators INT1 and INT2 are operating, and their outputs a, v, and d are continuously output.

When the IS start command is communicated from the camera body CMR, the process proceeds from step (203) to (204).

In step (204), only the integrator INT2 is reset to "0". This is because when the image blur correction is started in the next step, the correction optical system ILNS has its origin (the middle point of the movable range, that is, the position where the central axis of the correction optical system ILNS coincides with the optical axis C in FIG. 1). This is because the drive is started more and the stroke can be used effectively.

In step (205), the drive circuit IDR of the motor IMTR is operated. When the circuit becomes operable, the signal of the operational amplifier AMP is input, and the drive of the motor IMTR is controlled according to this signal.In the initial stage of the operation, the displacement signal d, which is the positive input signal of the operational amplifier AMP, is initialized. Since it is "0", the amplifier AMP, drive circuit IDR and motor IMT
R controls the drive so that the output of the position detection sensor PSD is "0", that is, the correction optical system ILNS comes to the origin (movable center position). This is called a centering operation. After that,
Since the displacement signal d corresponding to the shake starts to be output from the integrator INT2, the displacement dL of the correction optical system ILNS is driven and controlled so that dL = d, whereby the displacement dL on the image forming plane, that is, on the focus glass PG is obtained. The image comes to rest.

In the next step (206), the state of the switch SW2 is detected by communication, and if the switch SW2 is off, the step (20) is performed.
Go to 7).

In step (207), an IS stop instruction is also detected by communication, and if an IS stop instruction has been received, step (20) is performed.
The process proceeds to 8), and if it is determined that the IS stop instruction has not been received, the process returns to step (206). That is, if only switch SW1 is on and switch SW2 is off, steps (206) and (207)
Is repeatedly executed, and during this time, image blur correction is performed.

In step (208), the driving of the drive circuit IDR is stopped, that is, the image blur correction operation is stopped, and the process returns to step (203).

When the switch SW2 is recognized to be turned on in the step (206), the process proceeds to a step (211).

In step (211), among the positions of the correction optical system ILNS,
The magnitude of the displacement dLi and the allowable displacement dcr in the direction of the arrow di in FIG. 2 or in the direction of the coordinate axis i in FIG. 4 is determined. Here, the allowable displacement dcr is determined as follows.

In this embodiment, the open F number of the photographing lens is F2.8,
If the permissible circle of confusion is φ0.035mm, the depth of focus is about ± 0.1mm
Becomes That is, if the focus shift is larger than ± 0.1 mm, the photograph becomes out of focus. Therefore, in FIG. 4, the point at which the i-axis intersects with the contour line of δ = −0.1 is the allowable displacement dcr, and the focus shift is large outside this, so that it is easy and reasonable to set the release prohibited area. Similarly, in the j direction, the intersection of the j axis and the contour line of δ = + 0.1 is defined as the allowable displacement dcr.

In step (211), the magnitude of the i-direction displacement dLi and the allowable displacement dcr is determined using the allowable displacement dcr determined as described above. If | dLi | ≦ dcr, the process proceeds to step (212).

In step (212), j-direction displacement dLj is determined, and | d
If Lj | ≦ dcr, the process proceeds to snap (213).

In step (213), "0" is stored in the flag LFLG, and the flow shifts to step (214).

In step (214), the fact that "0" is stored in the flag LFLG is transmitted to the microcomputer LCPU in the lens.

Then, the microcomputer LCPU in the lens transmits LFLG = 0 to the microcomputer CCPU in the camera, and this is substantially a release start permission signal, and the release operation is started.

In step (215), whether or not the release operation has been completed is detected by monitoring communication between the microcomputer CCPU in the camera and the microcomputer LCPU in the lens. When the completion is detected, the process returns to step (207).

If it is determined in step (211) or (212) that one of the lens displacements in the i and j directions exceeds the allowable displacement dcr, the process proceeds to step (216).

 In step (216), LFLG = 1 is set.

Then, in the next step (217), “LFLG = 1” is transmitted to the microcomputer LCPU in the lens.

The microcomputer LCPU in the lens is the microcomputer CCPU in the camera.
, Which is essentially a release hold signal.

In step (218), it is determined whether or not the release cancel signal in step (029) in FIG.
If not, the process returns to step (211), and steps (211) → (2) until | dLi | and | dLj | are both equal to or less than the allowable displacement dcr.
12) → (216) → (217) → (218) loop is repeated. Then, after a lapse of a predetermined time (T _O ), step (218)
When the release cancel signal is recognized at step (208), the flow shifts to step (208) to stop the image blur correction operation, and returns to step (203). If the switch SW1 is turned on, the position of the correction optical system is initialized from step (204), that is, centering is performed, and image blur prevention is started again.

FIG. 8 shows a release prohibition area realized in the above flow, and the coordinate axes and the like correspond to FIG.
That is, with respect to the movable range ± dmax of the i, j axis correction optical system 33,
When the displacement dL of the correction optical system exceeds ± dcr, the release is prohibited, and the area indicated by hatching in FIG.

FIG. 9 is a control flowchart of the microcomputer LCPU in the lens.

When the power supply of the camera CMR is turned on, power is started to be supplied from the camera CMR to the lens LNS via the mount contact between the lens and the camera, and the microcomputer LCPU in the lens starts executing a predetermined sequence program.

In step (302), switch SW1 is switched from camera CMR.
While the ON signal does not come, all the control flags and variables set in the RAM in the microcomputer LCPU in the lens are cleared and initialized in step (303).

When an ON signal of the switch SW1 is transmitted from the camera CMR, the flow shifts to step (304), where "communication 1" is executed. This corresponds to “lens communication 1” in step (004) in FIG. 5, and the ROM of the microcomputer LCPU in the lens is used.
Transmits various information stored in the microcomputer to the microcomputer CCPU in the camera.

When the microcomputer CCPU in the camera performs a focus detection calculation and transmits a lens drive command, it receives the command in step (305) and controls the drive of the focus adjusting lens FLNS in the next step (306).

When the lens drive is completed, a drive completion signal is transmitted to the microcomputer CCPU in the camera in step (307), and the process returns to step (302).

While executing step (306), switch SW2 is output from camera CMR.
When the communication of the ON signal is received, the interrupt is permitted and the process proceeds to step (311).

ON signal of switch SW2 is microcomputer ICPU for image blur correction
Is received, and a flag LFLG relating to the placement of the correction optical system ILNS is transmitted. In step (312), this is received.
In the next step (313), the flag LFLG is transmitted to the microcomputer CCPU in the camera.

In step (314), it is determined whether or not a release permission signal (a narrowing down command in this embodiment) has been received from the microcomputer CCPU in the camera. If NO, the process returns to step (312).

If it is determined in step (314) that the release is permitted, that is, that the stop-down command has been transmitted, the stop-down stepping motor DMTR is driven in step (315) to perform the stop-down operation.

In step (316), the driving of the focus adjusting lens FLNS is prohibited.

In step (317), the completion of the narrowing down is recognized, and this is transmitted to the microcomputer CCPU in the camera.

Then, the camera CMR receives this, performs shutter control, and starts film exposure.

Next, the microcomputer CCPU in the camera transmits an aperture opening command, and upon receiving this in step (318), performs an aperture opening operation in the next step (319).

When the aperture opening operation is completed, a completion signal is transmitted to the microcomputer CCPU in the camera in step (320), and the operation proceeds to step (30).
Return to 2).

 The flow of FIGS. 5 to 9 will be outlined again.

When the microcomputer CCPU in the camera recognizes that the switch SW1 is turned on, it sends a SW1 on signal to the microcomputer LCPU in the lens and the microcomputer ICPU for image blur correction.

When the switch SW1 is turned on, the microcomputer CCPU in the camera performs an exposure calculation and a focus detection calculation, and the microcomputer LCPU in the lens receives this to drive the focus adjustment lens. Also, the image blur correction microcomputer ICPU starts an image blur correction operation.

When an interrupt of the ON signal of the switch SW2 occurs, the microcomputer ICPU for image blur correction transmits a flag LFLG regarding the position of the correction optical system 33 for image blur correction to the microcomputer CCPU in the camera via the microcomputer LCPU in the lens. = 0, the microcomputer CCPU in the camera starts the release operation, and “LFLG
If “= 1”, release is prohibited and wait until “LFLG = 0”. If “LFLG = 0” is not reached even after the predetermined time has elapsed, the release is cancelled.

With the above operation, while monitoring the flag LFLG, when the focus shift is large, the release is prohibited, and when the focus shift becomes small, the prohibition is released.

In the first embodiment, when the out-of-focus state is large, the release is prohibited, and the apparatus waits until the out-of-focus state becomes small. Therefore, a photograph having no problem with out-of-focus or blur can be taken, but there is a risk of missing a shutter chance. Therefore, in the second embodiment, when the out-of-focus state is large, the correction optical system ILNS is centered and then released, so that an increase in the release time lag can be prevented, and a shutter chance is not missed.

FIG. 10 is a flow chart of the second embodiment. Steps (217) and (21) are different from the flow chart of FIG. 7 of the first embodiment.
Only the point where (221) and (222) are newly inserted between 8) is different. Therefore, only this changed portion will be described.

If the displacement of the correction optical system ILNS is large and NO is determined in step (211) or (212), step (216)
In step (217), "1" is stored in the flag LFLG, and "LFLG = 1" is transmitted to the microcomputer LCPU in the lens in step (217) to hold the Reliniz.

In the next step (221), the integrator INT2 is reset to "0".

Then, the output of the integrator INT2 becomes d = 0 at that moment, so that the correction optical system ILNS is centered so that the displacement dL becomes “0”. The time required for the centering operation is determined by the feedback gain of the feedback loop composed of the operational amplifier AMP and the drive circuit IDR.
Centering in msec is possible.

In step (222), the delay timer is prevented from proceeding to the next step until the centering is completed. Here, the delay time is set to 100 msec.

Next, in step (218), it is determined whether or not a release cancel signal has been received from the camera CMR. If NO, the process returns to step (211).

In the second embodiment, if the centering operation is performed once, the process returns to steps (211) and (212) again.
It is not usually possible to determine NO. In other words, since the flow of steps (216) to (218) can be normally passed only once and branched to step (213), the release time lag is suppressed to 100 msec.

As described above, in the second embodiment, when the switch SW2 is turned on and the displacement of the correction optical system ILNS is within the allowable displacement dcr for both the i and j axes, the release operation can be immediately started (this is the first operation). Same as the embodiment). On the other hand, when any one of the i and j axes is outside the allowable displacement dcr, the centering operation is performed and then the release operation is started. Only in this case, the release time lag is slightly increased, and the framing of the photographing screen is slightly changed by the centering. However, since the focus can be relieved, the effect is great.

In the first and second embodiments, a focus shift occurred due to a problem in the support structure of the correction optical system ILNS.
As the displacement of NS increases, a pure optical problem also arises. That is, it is an increase and unbalance of each aberration such as astigmatism and distortion, and an unbalance of the image surface light amount. Therefore, even with a configuration in which the correction optical system can be displaced completely perpendicularly to the optical axis, as in Japanese Patent Application Laid-Open No. 63-155038 by the applicant of the present application, the above-mentioned aberration problem occurs. Becomes

Further, in the case of performing image blur correction using a variable vertex angle prism described in JP-A-2-41757, etc., as the vertex angle of the prism is increased to increase the optical axis eccentricity,
The occurrence of chromatic aberration increases. In such a case, even if the release is performed, a good photograph cannot be obtained, so that it is desirable to prohibit the release. FIG. 11 shows the configuration of the third embodiment.

In this embodiment, a variable apex angle prism VP is provided at the lens tip instead of the correction optical system ILNS as an optical axis decentering means for image blur correction. The variable apex prism VP is composed of two transparent parallel flat plates, an accordion film, and an enclosed liquid. The tilt in the vertical direction (pitch) due to the tilt of the flat plate on the subject side causes the tilt of the flat plate on the lens side. Shake in the yaw direction can be corrected.

In FIG. 11, PACT is an actuator for tilt-driving the variable apex prism VP, PSD is a position detection sensor for detecting the prism tilt angle, that is, the amount of eccentricity of the optical axis, PDR is a drive circuit for driving the actuator PACT, and AMP is an operational amplifier. .
The infrared light emitting diode IRED and the slit SLT are omitted, and the drive system in the yaw direction is also omitted. The configuration and the image blur correction principle are basically the same as those of the first embodiment, and the detailed description is omitted.

FIG. 12 shows a flowchart in the third embodiment.

This flow differs from the flow of the second embodiment shown in FIG. 10 only in that steps (211) and (212) are replaced by (231) and (232).

In FIG. 11, since the optical axis eccentric direction for performing image blur correction is obtained by combining vertical (pitch) and horizontal (yaw), the vertical direction is defined as the y axis, the horizontal direction is defined as the X axis, and each direction is defined. The optical axis eccentricity due to the prism action is dLy, dLx. And in step (231), register dLxy Store the value of.

In step (232), the magnitude of the value dLxy and the allowable displacement dcr is determined. Here, the allowable displacement dcr is an optical axis eccentricity limit at which the influence of chromatic aberration by the variable apex angle prism VP can be tolerated. And if | dLxy | ≦ dcr,
Assuming that image deterioration is acceptable, proceed to step (213), and | dL
If xy |> dcr, it is determined that the image deterioration is large, and step (21)
Proceeding to 6), store "1" in the flag LFLG to inhibit release, reset the integrator INT2 in step (221), and perform the centering operation of the variable apex prism VP.

FIG. 13 is a view showing a release prohibition area in the third embodiment, and is similar to FIG.

The optical axis eccentricity by the variable vertical angle prism VP is ± d in both x and y directions.
Although it is possible to reach the maximum, the outside of the radius dcr centered on the origin indicated by hatching is the release prohibition area.

According to each of the above embodiments, when the optical axis eccentricity due to the image blur correction exceeds a predetermined value, the release is prohibited because it is determined that the image is degraded beyond the allowable limit due to focus shift or aberration. Since the release is permitted when the axial eccentricity is within the predetermined value, the image blur correction is performed satisfactorily,
In addition, a photograph without image deterioration can be obtained.

Further, when a release command is issued when the optical axis eccentricity is equal to or more than a predetermined value, the release is permitted after the correction optical system is centered, so that an increase in the release time lag can be minimized. it can.

(Correspondence between the Invention and the Embodiment) In this embodiment, the correction optical system ILNS or the variable apex angle prism VP is used as the variable means of the present invention, and a microcomputer IC for image blur correction.
The functional part of the PU that executes step (205) in FIG. 7, FIG. 10 or FIG. 12 is provided to the operation control means of the present invention by the microcomputer (FIG. 7 or FIG. 10) in FIG.
1), (212) or the functional part for executing steps (231) and (232) in FIG. 12 is used as the determination means of the present invention, and the image blur correction microcomputer ICPU of FIG. 7, FIG. 10 or FIG. A function part for executing steps (213) and (216) of the present invention is a prohibiting means of the present invention, and a function part for executing step (221) in FIG. 10 or FIG. These correspond to the operation control means of the present invention described above.

(Effect of the Invention) As described above, according to the first aspect of the present invention, an image blur prevention apparatus that can prevent photographing from being performed in a state where image blur prevention is not properly performed. Can be provided. According to the second aspect of the present invention, when the signal corresponding to the displacement of the movable means becomes a value indicating that the displacement is smaller than the predetermined displacement, the exposure prohibition can be canceled, and the image blur can be properly prevented. It is possible to provide an image blur prevention apparatus according to claim 1, which can perform shooting without image deterioration. Further, according to the third aspect of the present invention, it is possible to provide an image blur prevention apparatus according to the second aspect, which can prevent an increase in release time lag and does not miss a photo opportunity.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention, FIG. 2 is a perspective view showing a correction optical mechanism, FIG. 3 is a view showing a drive locus of the correction optical mechanism, and FIG. FIGS. 5 to 7 and 9 are flow charts showing the operation, FIGS. 5 to 7 and 9 are flowcharts showing the operation, FIG. 8 is a view explaining the release prohibition area, and FIG. 10 is a second embodiment of the present invention. 11 is a block diagram showing a third embodiment of the present invention, FIG. 12 is a flowchart showing the image blur correction operation, and FIG. 13 is a release inhibition area. FIG. 14 is a block diagram schematically showing a general image blur correction device. ACC, 1i, 1j …… Accelerometer, INT1, INT2 …… Integrator, ILNS
…… Correction optical system, CCPU …… Microcomputer in camera, LCPU ……
Microcomputer in lens, ICPU ... Microcomputer for image blur correction, PS
D: Position detection sensor, SNS: Focus detection sensor, IRED
… Infrared light emitting diode, IMTR …… Motor, IDR …… Drive circuit, VP… Variable angle prism, PDR …… Drive circuit.

Continuation of the front page (56) References JP-A-2-157732 (JP, A) JP-A-1-185611 (JP, A) JP-A-1-298332 (JP, A) JP-A-59-222823 (JP) , A) JP-A-2-116835 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03B 5/00 G03B 17/00

Claims (3)

(57) [Claims] A movable means for preventing image blur; an operation control means for starting an operation of the movable means in response to an operation performed prior to an operation for causing a camera to perform a photographing operation; Means for judging a signal corresponding to the displacement of the movable means in response to an operation for causing the camera to perform a photographing operation in a state where the camera is operating; and a signal corresponding to the displacement is determined by the judging means. An image blur prevention device comprising: a prohibition unit that prohibits exposure of a camera when it is determined that the value indicates a value greater than a displacement. 2. The prohibition means cancels the exposure prohibition when the determination means determines that a signal corresponding to the displacement has a value indicating that the signal is smaller than a predetermined displacement. 2. The image blur prevention device according to claim 1, wherein: 3. The image according to claim 2, wherein said operation control means causes said movable means to perform a centering operation toward a center position of an operation range after said exposure is prohibited by said prohibition means. Anti-shake device.