JPH0495932A - Camera with image blur correcting function and interchangeable lens for camera - Google Patents

Abstract

PURPOSE:To eliminate image deterioration such as defocusing by inhibiting releasing operation by a release control means when a displacement detecting means detects a correction optical system being displaced outside a specific range. CONSTITUTION:An angular accelerometer 1i detects a blur in a direction IOTAof a lens and a motor 51 is driven according to the blur signal to drive a fixed frame 37 and a lens holding frame 32 in a direction di. Further, and angular accelerometer 1j detects a blur in a direction J and a motor 61 is driven to drive a lens holding frame 32 in a direction dj through an intermediate lever 71. The two-dimensional blur on a photographic picture plane is corrected by the blur correcting operation in those two axial directions. Namely, when the lens is displaced so that a permissible defocusing quantity is generated, the release operation is inhibited. Consequently, an out-of-focus photograph is prevented from being taken.

Description

Detailed Description of the Invention (Field of Application of the Invention) The present invention relates to a camera with an image blur correction function that corrects image blur by driving a correction optical system based on a signal from a vibration detection means, and an interchangeable lens for the camera. This is related to the improvement of.

(Background of the Invention) Conventionally, various devices for correcting image blur in cameras have been proposed, such as Japanese Patent Laid-Open No. 63-49729.

In these systems, in order to prevent blurring of the image on the imaging surface caused by vibrations of the camera, a method is adopted in which the optical axis decentering means, which is the controlled object, is moved by a feedback control mechanism to suppress the blurring of the image. It is being

For example, camera shake vibration (usually tilt vibration of the camera with respect to the photographing optical axis) is detected as an acceleration signal, and this acceleration signal is integrated by a signal processing system to obtain a velocity signal (and a displacement signal). The optical axis decentering means is configured to drive the optical axis decentering means in a vibration suppression direction (the apparent direction of image formation is a direction in which upper vibrations are suppressed).

FIG. 14 shows an example of the basic configuration of an image blur correction device including such a signal processing system. Detects tilting as an acceleration signal. The detected acceleration signal a is integrated into a velocity signal 2 by a first integrator 2, and further converted into a displacement signal d by a second integrator 3.

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

Reference numeral 6 denotes a position detection sensor constituting a position detection means for detecting the actual positional displacement of the optical axis eccentricity means 4, and a signal from this position detection sensor 6 is sent to the input system of the actuator 5 via an operational amplifier 7. A feedback loop is configured in which the drive control of the optical axis eccentric means 4 is made to correspond to the vibration displacement by feeding back.

Here, if the drivable range of the optical axis decentering means 4 is small with respect to the camera shake displacement amplitude, the optical axis decentering means 4 will use up its displacement stroke when performing the image blur correction operation.
After that, no image stabilization is performed. Therefore, if this stroke is used up frequently, the blur correction effect will hardly be noticeable to the photographer. Therefore, conventionally, the drivable range of the optical axis decentering means 4 is generally configured to have a sufficient amount to correct normal camera shake vibrations.

However, as the driveable range of the optical axis decentering means 4 is expanded, the following problems occur.

1) Depending on the method of supporting the optical axis decentering means 4, when it is displaced in a direction perpendicular to the optical axis, a small displacement also occurs in the optical axis direction.

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

That is, in order to improve the image blur correction ability, it is preferable that the drive range of the optical axis decentering means 4 is wide. However, if the release is released at the moment when the displacement of the means 4 becomes large, Even if the correction is well made, the resulting photograph will be out of focus or have large aberrations, making it impossible to obtain a high-quality photograph.

(Object of the Invention) The object of the present invention is to solve the above-mentioned problems and to provide a camera with an image stabilization function and a replacement for the camera, which can appropriately correct blur and obtain photographs without image deterioration such as out-of-focus. The objective is to provide lenses.

(Features of the Invention) In order to achieve the above object, the present invention prevents the release operation by the release control means when the displacement detection means detects that the displacement of the correction optical system is outside a predetermined range. The present invention is characterized in that a release prevention means is provided to prevent the release operation when the correction optical system is displaced to such an extent that image deterioration is expected.

(Embodiments of the Invention) Hereinafter, the present invention will be described in detail based on illustrated embodiments.

1 to 9 show a first embodiment of the present invention, and FIG. 1 is a diagram showing the main parts 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 side will be explained.

The ccpu is an in-camera microcomputer (hereinafter referred to as microcomputer), which is a one-chip microcomputer that has ROM, RAM, and A/D conversion functions. Camera microcontroller ccpu
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. To this end, the microcomputer ccpu in the camera communicates with peripheral circuits and lenses in the camera body CMR to control the operation of each circuit and lens.

LCM is a lens communication buffer circuit, and the power line V
L supplies power to the lens LNS and serves as an inter-lens communication buffer for outputting from the camera body CMR to the lens LNS via the signal line DCL and from the lens LNS to the camera body CMR via the signal line DLC.

SNS is a line sensor for focus detection (hereinafter simply referred to as sensor) consisting of a CCD, etc., and SDR is its drive circuit.
S is driven, the image signal from the sensor SNS is taken in, amplified, and sent to the microcomputer ccpu in the camera.

The light from the lens LNS passes through the main mirror MM, focusing glass PG, and pentaprism PP to the photometric sensor SPC.
The output signal is input to the in-camera microcomputer CCPU, which performs automatic exposure control (A) according to a predetermined program.
E).

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 internal microcomputer CCPU, and displays the on/off status of various camera operation members within the camera by communication. Notify the microcomputer ccpu.

Switch SW1. SW2 is a switch linked to a release button (not shown); when the release button is pressed to the first stage, the switch SWI is turned on, and when the release button is pressed to the second stage, the switch SW2 is turned on. In-camera microcomputer c
As will be described later, when the switch SWI is turned on, the CPU generates a start signal for photometry, automatic focusing operation, and image blur correction operation, and when the switch SW2 is turned on, it performs exposure control and film winding. Note that the switch SW2 is connected to the "interrupt input terminal" of the microcomputer CCPU in the camera, and even if the program is being executed when the switch SWI is on, an interrupt is generated by turning on the switch SW2, and the program can immediately proceed to a predetermined interrupt program.

MTRI is for film feeding, MTR2 is for mirror up/
This is a motor for down and shutter spring charging, and forward and reverse rotation is controlled by respective drive circuits MDRI and MDR2.

MGI and MG2 are magnets for starting the movement of the front and rear shutter curtains, respectively, and are amplification transistors TRI.

The TR2 is energized, and the camera's internal microcomputer CCPU performs shutter control.

Next, the configuration on the lens LNS side will be explained.

The LCPU is a microcomputer in the lens, and the microcomputer cc in the camera.
It is a one-chip microcomputer with the same ROM, RAM, and A/D conversion functions as the PU. In-lens microcomputer LCPII
controls the driving of the focusing lens FLNS and the aperture according to commands sent from the camera body CNR via the signal line DCL.

In addition, various operating conditions of the lens (how much the focusing optical system is driven, how many steps the aperture is stopped, etc.) and parameters (open F number, focal length, etc.)

(coefficient of defocus amount vs. feed amount, etc.) on the signal line DL.
It is sent to the camera side via C.

FMTR is a motor for driving the focusing lens FLNS, which rotates a helicoid ring (not shown) via a gear train.
Focus adjustment is performed by moving the lens FLNS back and forth in the optical axis direction.

The FDR is a drive circuit for the motor FMTR, and controls the forward/reverse rotation, braking, etc. of the motor FMTR in accordance with signals from the microcomputer LCPU in the lens.

This embodiment shows an example of an inner focus type, and 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 to adjust the focus. Adjustment lens FLN
The amount of movement of the focus adjustment lens FLNS, which performs focus adjustment by moving S in the optical axis direction, is monitored by the pulse signal of the encoder circuit ENCF, and the in-lens microcomputer LCPII
The motor FMTR is controlled when a predetermined movement is completed.

For this reason, once a focus adjustment command is sent from the camera body CMR, the in-camera microcomputer ccpu does not need to be involved in lens driving at all until the lens driving is completed. Further, the configuration is such that the contents of the counter can be sent to the camera body CMR as necessary.

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

ICP [I is a microcomputer for image stabilization, which controls the image stabilization operation and sends a signal D from the camera body CMR to the lens LNS.
CL, signal DL from lens LNS to camera body CMR
C is input, and the output signal from the microcomputer ICPυ is input to the in-lens microcomputer LCPU. In other words, communication with the camera's internal microcomputer ccpu is carried out by the lens' internal microcomputer LCPI.
The image blur correction microcomputer rcpu intercepts communication between the two. Then, from the image stabilization microcomputer rcPU to the in-camera microcomputer ccpu
Communication to is performed via the microcomputer LCPU within the lens.

ACC is an accelerometer (more precisely, an angular accelerometer) that detects lens shake, and sends an (angular) acceleration signal a to the integrator lNTl. The integrator TNTI integrates the (angular) acceleration signal a and outputs the (angular) velocity signal V to the image blur correction microcomputer lCPU.
and is sent to the integrator INT2. Integrator INT2 is (angle)
The velocity signal V is integrated and the (angular) displacement signal d is sent to the image blur correction microcomputer TCPII, and the operational amplifier AM
Send it to the positive input terminal of P. On the other hand, the outputs of the integrators 1NT1 and INT2 can be reset to "0" as required by reset signals R3I and R32 from the image blur correction microcomputer ICPII.

ILNS is a correction optical system which is an optical axis decentering means.
It is supported by a link mechanism, which will be described later, and can move approximately parallel to a plane perpendicular to the optical axis.

IMTR is a motor for image stabilization, which rotates the cam fixed on the motor shaft forward and reverse, and controls the correction optical system ILNS.
to displace it.

IDR is a drive circuit for the image blur correction motor IMTR.
The motor IM is controlled by the output signal from the operational amplifier AMP.
Drives TR in forward and reverse directions.

PSD is the position detection sensor of the correction optical system ILNS,
Light from the infrared light emitting diode IRED is used in the correction optical system IL
By passing through the slit SLT that moves together with the NS and entering the light receiving surface of the position detection sensor PSD, the position detection sensor PSD determines the position of the incident light, that is, the correction optical system ILN.
A position signal dL of S is generated.

This output signal (dL) is then output by the image blur correction microcomputer l.
It is input to the minus side input terminal of the CPU and operational amplifier AMP.

5WIS is the main switch of the image stabilization operation circuit, and when the switch 5WIS is turned on, the image stabilization microcomputer l
Power is applied to the CPU and its peripheral circuits, and then the divider lNT1. IN
T2 is reset and the blur signal is initialized. When the switch SW1 of the camera body CMR is turned on, this signal is communicated to the image stabilization microcomputer ICPCI via the lens microcomputer LCPU, and the motor IMTR
is driven and the image blur correction operation starts.

In addition, although it was previously assumed that dL is 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, even if dL is regarded as the amount of optical axis eccentricity, No problem. The origin of this signal is the position where the central axis of the correction optical system ILNS and the photographing optical axis coincide.

In Figure 1, the image stabilization mechanism only shows one axis, but since camera shake occurs in two-dimensional directions (up, down, left and right), an actual lens detects blur in two axes, and the correction optical system IL
NS must also be operated two-dimensionally.

FIG. 2 shows the support mechanism of the correction optical system ILNS in detail, and is a perspective view viewed diagonally from the front on a horizontal plane including the optical axis. Normally, shake is detected and corrected by dividing it into two axes: vertical direction (pitch) and horizontal direction (yaw), but in this example, the above two directions are 45" tilted axis and J direction. The reference axis for image stabilization is set.

In Figure 2, arrow G is the direction of gravity, 1i, lj
is an angular accelerometer that detects the angular shake of the photographing optical axis C in the ■ direction and the J direction, which corresponds to ACC in Fig. 1; The direction blur, that is, the angular acceleration aj is detected by the angular accelerometer 1j. 3
1 is a fixed frame fixed to the photographic lens body, and 37 is a movable frame which is connected to the fixed frame 31 by plates 35, 36 and flexible tongues 37 to 4o, and is movable in the direction of arrow di. 32 is a lens holding frame that holds the correction optical system 33 (this corresponds to the ILNS in FIG. 1) and holds the plate 41.4.
2 and flexible tongues 43 to 46 to the movable frame 37, and is movable relative to the movable frame 37 in the direction of the arrow dj force.

Reference numeral 51 denotes a di-direction driving motor, which corresponds to the IMTR in FIG. A cam 52 (
This corresponds to CAM in FIG. The wire 55 wound around the pulley 53 is connected to one end of a spring 56, and the other end is hooked to a spring hook 57 implanted in the fixed frame 37. A contact force F acts between the cam follower 52 and the cam follower 54. The reason why the pulley 53 and wire 55 are used to generate this contact force is to prevent torque from being generated in the cam 52 due to the contact method. I will omit it here.

58 is a slit plate fixed to the moving frame 37, as shown in FIG.
It corresponds to LT and is an infrared light emitting diode (IRED in Figure 1).
The position of the movable frame 37 in the di force direction is detected by a known method using a position detection sensor (corresponding to the PSD in FIG. 1) 59, a position detection sensor (corresponding to the PSD in FIG. 1) 60, and a slit 58a of the slit plate 58.

Reference numeral 61 denotes a motor that drives the lens holding frame 32 in the dj force direction, and is fixed to the flat support portion 31j of the fixed frame 31 via the motor stand 48. Similarly, the motor shaft 61a has a cam 62.
A pulley 63 is fixed and a wire 65. The cam 62 and the cam follower 64 are brought into contact with each other by 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 connected to the fixed frame 31 via a flexible tongue 72, and is capable of swinging in the direction of the force indicated by the arrow θj. is in contact with the flat portion 32j of the lens holding frame 32. Therefore, the rotation of the cam 62 causes the cam follower 64. The intermediate lever 71 and the intermediate bearings 73 and 74 are integrally displaced in the θj force direction, which causes the lens holding frame 3
2 is moved in the direction of the dj force. The displacement of the movable frame 37 in the di force direction is determined by the flat portion 32 of the lens holding frame 32.
j and the intermediate bearings 73, 74, interference between the di force direction dj force direction movements is avoided. Further, a slit plate 68 is fixed to the lens holding frame 32, and the displacement of the lens holding frame 32 in the dj force direction is detected by an infrared light emitting diode 69 and a position detection sensor PSD70.

With the above configuration, the angular accelerometer 1 measures the blurring of the lens in the working direction.
1, and by driving the motor 51 based on this shake signal, the fixed frame 37 and the lens holding frame 32 are
The intermediate lever 71 is driven in the force direction, and the vibration in the J direction is detected by the angular accelerometer 1j to drive the motor 61.
The lens holding frame 32 is driven in the direction of the dj force. By performing blur correction operations in these two axial directions, it is possible to correct two-dimensional blur on the photographic screen.

Now, the locus of movement of the moving frame 37 will be explained in more detail.

It was mentioned earlier that the moving frame 37 moves in the direction of the force indicated by the arrow di, but strictly speaking, it draws an arcuate locus whose radius is the length β of the plates 35 and 36. This is shown in FIG. The direction of the half-turn attack is the same as in Figure 2.

First, the movement of the moving frame 37 in the direction of the force indicated by the arrow di is precisely a movement along an arc Ai'. Therefore, the movement of the moving frame 37 along the arc Ai' becomes a movement along the arc Ai in the correction optical system 33. That is, when attempting to move in the direction of the arrow di force, when the origin is on the optical axis, as the absolute value of the displacement in the di force direction increases, the correction optical system 33 will move forward on the optical axis. . Similarly, when the motor 61 attempts to move the correction optical system 33 in the dj force direction, its locus becomes a circular arc Aj, and as the absolute value of the displacement in the dj force direction increases, the correction optical system 33 retreats toward the film surface side. do.

That is, when the central axis of the correction optical system 33 is located at a position deviated from the photographing optical axis, a slight movement occurs in the optical axis direction, and the amount is the sum of the displacement amounts of the arcs Ai and Aj in the optical axis direction. becomes.

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

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

Generally, the correction optical system 33 that decenters the optical axis has imaging power, and if the correction optical system 33 is displaced in the direction perpendicular to the optical axis, it will decenter the optical axis and produce images on the imaging plane. Shift the image (this is the principle of image stabilization). on the other hand,
When the correction optical system 33 moves in the optical axis direction, the imaging position moves in the optical axis direction. Therefore, in this embodiment, in order to simplify the explanation, the amount of shift in the optical axis vertical direction of the correction optical system 33 = the amount of shift of the image = dL, the amount of movement in the optical axis direction of the correction optical system 33 = the amount of focus movement = δ. . FIG. 4 shows the relationship between dL and δ.

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

Here, when the correction optical system 33 is displaced in the i direction (either positive or negative) as explained in FIG. Moving. The sign of the minute movement amount δ at this time is assumed to be negative. on the other hand,
Displacement in the j direction is a movement toward this side of the paper, and the sign of δ at this time is assumed to be positive. Brates 35 and 36 in Fig. 2
, 41. If the lengths of 42 are all the same, the correction optical system 33
When is displaced in the X direction (either positive or negative) or the Y direction (either positive or negative), the movement in the optical axis direction is canceled out and becomes "0".

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

There is no problem if the amount of defocus δ is within the depth of focus of the lens, but if it exceeds the depth of focus, the image will be out of focus with the bottle. Therefore, in the present invention, the lens displacement d
If L exceeds the lens displacement (±d cr) that generates an allowable amount of defocus (for example, δ=±0.1 mm), release is prohibited to prevent out-of-focus photographs.

The operation of the camera and lens with the above configuration will be explained according to a flowchart.

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

FIG. 5 is a flowchart showing the overall 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 switch SW1, which is turned on by pressing the first step of the release button, is detected in step (001) and step (002), and when SWI is off, the process proceeds to (003). Then, all control flags and variables set in the RAM of the camera microcomputer ccpu 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 performed by the switch SWI.
It is executed repeatedly until the power switch is turned on or the power switch is turned off.

Step (002) by turning on the switch SWI
to (011).

In step (011), lens communication 1 is performed. This communication is for obtaining the information necessary to perform exposure control (AE) and focus adjustment control (AF).
pu connects to the microcomputer LC in the lens via the signal line DCL
When a communication command is sent to the PU, the microcomputer LCP inside the lens
(I transmits information such as the focal length, AF sensitivity, and open F-number stored in the ROM via the signal line DLC.

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

In step (013), a "photometering" subroutine for exposure control is executed. In other words, the in-camera microcontroller ccp
u inputs the output of the photometric sensor sPc shown in FIG. 1 to an analog input terminal, performs A/D conversion, and obtains the digital photometric value Bv.

In step (014), an "exposure calculation" subroutine is executed to obtain an exposure control value. In this subroutine,
Shutter value Tv and aperture value A according to the apex calculation formula rAv+Tv=Bv+SvJ and a predetermined program diagram.
v is determined and stored at a predetermined address in 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 amount of defocus of the photographing lens is calculated based on the input image signal.

The subroutine flow of steps (015) and (016) described above has been disclosed by the present applicant in Japanese Patent Application No. 160824/1983, and so a detailed explanation thereof will be omitted here.

Subsequently, in step (017), a "lens drive" subroutine is executed. In this subroutine, the camera body CMR
The number of driving pulses for the focusing lens FLNS calculated in the step (016) on the side is sent to the lens microcomputer LCPU.
After that, the microcomputer LCPU inside the lens
drives and controls motor FMTR according to a predetermined acceleration/deceleration curve. After the driving is completed, a termination signal is sent to the microcomputer CCPU in the camera, and this subroutine is terminated and the process returns to step (002).

Next, the above steps (015) to (01
A case will be described in which a release interrupt is generated by turning on the switch SW2 while executing each operation in the focus adjustment cycle shown in 7).

As explained earlier, switch SW2 is connected to the camera's microcomputer c.
It is connected to the interrupt input terminal of the CPU, and is configured so that when the switch SW2 is turned on, the interrupt function immediately shifts to step (021) even if any step is being executed.

If a switch SW2 interrupt occurs while executing the step surrounded by the broken line, the release prohibition timer R is activated at step (022).
Reset TIMEH (initialize to O). This timer RTIMER is a self-running timer built in the microcomputer CCPU in the camera, and is a timer that measures the time for the release inhibit operation after the interruption of the switch SW2, as will be described later.

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

First, when the in-camera microcomputer CCPU sends the on signal of the switch SW2 to the lens LNS side, the image blur correction microcomputer 1CPU receives this and determines the current position of the ILNS, that is, the position signal from the position detection sensor PSD. conduct. This determination means that the correction optical system IL
This is a determination as to whether or not the focus movement that occurs in response to the displacement of the NS is permissible. The amount of focus movement is determined by the correction optical system I
Once the optical characteristics of the LNS and the support structure of the correction optical system ILNS are determined, the rest becomes a function only of the displacement dL of the correction optical system ILNS, so that an acceptable correction optical system I can be determined.
If the displacement of the LNS is dcr, it can be determined whether or not out of focus is allowable based on the magnitude relationship between 1 dLl and dcr. Therefore, the image stabilizing microcomputer 1CPU sets the flag LFLG to rOJ when the displacement is permissible, and sets the flag LFLG to "1" when it is not permissible.
The in-lens microcomputer LCPU sends this to the in-camera microcomputer ccpu. flag LFLG
The settings will be explained using the flowchart in FIG.

In step (024), it is determined whether the aperture control value Av and the focus deviation allowable aperture value Avcr are large or small, and it is determined whether or not the release can be performed unconditionally.

The maximum amount of defocus is determined by the optical characteristics of the correction optical system ILNS, the supporting method, and the maximum displacement value.

In this embodiment, it is assumed that the maximum amount of focus deviation is ±0, 15 mm. On the other hand, when the aperture value is F4, the depth of focus is ±0.1
Since it is about 5 mm, when the aperture control value is smaller than this, the out-of-focus can be tolerated even if the displacement of the correction optical system ILNS is maximum. Therefore, if the aperture value Av=4 in the apex calculation formula corresponding to F4 is set to Avcr, then step (027
), and the release operation begins. On the other hand, A v <A
At the time of vcr, there is a possibility that a focus deviation exceeding the allowable value may occur depending on the position of the correction optical system ILNS, so the process moves to step (025).

In step (025), a flag LFLG regarding the position of the correction optical system ILNS is determined. That is, LFLG=
When the value is O, it is determined that the camera is in a position where the focus shift is allowable, and the process moves to the release operation from step (027) onwards. L
When FLG=1, that is, if LFLG≠0, it is determined that there is a risk of defocus, and the process moves to step (026).
Release operation is suspended.

In step (026), timer R is set in step (022).
The elapsed time from the time when the TIMER was reset is compared with the upper limit value To for waiting for release start. And R
If TIMER<T 0, return to step (023) and repeat steps (023) to (025), and as a result of driving the correction optical system ILNS by blur correction,
Step (023) until LFLG=○, that is, the correction optical system ILNS enters the predetermined area and the focus shift is acceptable.
- (026) are repeatedly executed. If LFLG does not become 0 within time To, step (026
), it is determined that RTIMER≧T0 is YES, a release cancel signal is communicated to the lens in step (029), and the process returns to step (002) without performing the release.

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

In step (02B), film winding is performed.

With the above steps, shooting for one frame is completed, and step (0
Return to 02).

Next, the above-mentioned "release" subroutine will be described using FIG.

The main mirror MM is mirror-uped in step (102) via 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 013) is sent to the lens LNS side to perform aperture control.

In step (104), the previous step (+02), (
It is determined whether the mirror up and aperture control in step 103) have already been completed. Mirror up is main mirror MM
This can be confirmed using a detection switch (not shown) attached to the lens, and for aperture control, it is confirmed via communication whether 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 status. When both controls are confirmed, the process moves to step (105). At this point, preparations for exposure are complete.

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

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

In the next step (108), similar to step (104), the process waits for mirror down and aperture opening control to be completed. When both mirror down and aperture opening control are completed, the process moves to step (+09) and returns.

Next, the image blur correction operation performed on the lens LNS side will be explained using the flowchart of FIG. 7.

In step (201), the main switch 5 for image stabilization
When the WIS is turned on, power is turned on to the image blur correction microcomputer 1CPU and its peripheral circuits.

In step (202), two integrators lNTl, IN
Reset T2 and initialize its outputs v and d to "0".

In step (203), an IS start command is determined, and if no IS start command has been received from the camera body CMR, the process remains in step (203). In this state, image blur correction is not performed, but the accelerometer ACC and two integrators l
NTl and INT2 are operating, and their outputs a, v,
d continues to be output.

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

In step (204), only the integrator INT2 is reset to rOJ. This means that when starting image blur correction in the next step, the correction optical system ILNS moves to its origin (the middle point of the movable range, that is, the central axis of the correction optical system ILNS and the optical axis C in Fig. 1).
This is to enable the stroke to be used effectively by starting the drive from the position where the strokes match.

In step (205), the drive circuit ID of the motor lVTR is
Run R. When the circuit becomes operational, the signal from the operational amplifier AMP is input, and the motor IMT is activated according to this signal.
However, at the initial stage of operation, the displacement signal d, which is the positive input signal of the operational amplifier AMP, is set to "0" due to initialization, so the amplifier AMP, the drive circuit IDR, and the motor IMTR control the position. Detection sensor PS
Drive control is performed so that the output of D is "O", that is, the correction optical system ILNS comes to the origin (movable center position). This is called a centering operation. After that, the integrator INT2 starts outputting a displacement signal d corresponding to the blurring, so the displacement dL of the correction optical system ILNS is drive-controlled so that dL=d. The image above appears to be stationary.

In the next step (2061, the switch SW2 is
The state of switch SW2 is detected, and if the switch SW2 is off, the process moves to step (2Q7).

In step (207), an IS stop command is similarly detected through communication, and if an IS stop command has been received, the process moves to step (208), and if it is determined that no IS stop command has been received, the process moves to step (206). return.

That is, if only the switch SWI is on and the switch sw2 is off, steps (206) and (207) are repeatedly executed, and image blur correction is performed during this time.

In step (20B), the drive of the drive circuit IDR is stopped,
That is, the image blur correction operation is stopped and the process returns to step (203).

Further, if it is recognized in step (206) that the switch SW2 is on, the process moves to step (211).

In step (211), it is determined whether the displacement dLi and the allowable displacement dcr in the force direction of the arrow di in FIG. 2 or the coordinate axis i direction in FIG. 4 are determined in the position of the correction optical system ILNS. Here, the allowable displacement dcr is determined as follows.

The open F number of the photographic lens in this example is F2.8.
．． If the permissible circle of confusion is φ0.035 mm, the depth of focus is approximately ±0.1 mm. In other words, if the out-of-focus is larger than 2Q, Lm+n, the photograph will be out of focus.

Therefore, in Fig. 4, the point where the i-axis intersects with the contour line of δ = -0,1 is the permissible displacement dcr, and since the out-of-focus is large outside this point, it is easy and reasonable to set it as a release prohibited area. . Similarly, in the j direction, the i axis and δ= +
Let the intersection of the contour lines of Q and 1 be the allowable displacement dcr.

Using the allowable displacement dcr determined as above, in step (211), the magnitude of the i-direction displacement dLi and the allowable displacement dcr is determined, and if 1dLil≦dcr, step (211)
12).

In step (212), the j-direction displacement dLj is determined, and if 1aLjl≦dcr, the process moves to step (213).

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

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

Then, the microcomputer LCPtl inside the lens reads LFLG=0.
is transmitted to the microcomputer ccpu in the camera, and this essentially becomes a release start permission signal to start the release operation.

In step (215), the in-camera microcomputer ccpu is checked by the in-lens microcomputer LC to determine whether or not the release operation has been completed.
This is detected by monitoring communication with Ptl, and when completion is detected, the process returns to step (207).

Further, if either of the lens displacements in the i and j directions exceeds the allowable displacement dcr in step (211) or (212), the process proceeds to step (216).

In step (216), LFLG=1 is set.

Then, in the next step (217), rLFLG=I
Send J to the microcomputer LCPIJ inside the lens.

The in-lens microcomputer LCPU is the in-camera microcomputer c.
The signal is sent to the CPU, and this essentially becomes a release hold signal.

In step (218), it is determined whether or not the release cancel signal in step (029) in FIG.
Steps (211) - (212) - (216) - (
217) - (218) is repeated. and,
After the predetermined time (To) has passed, when the release cancel signal is recognized in step (218), the process proceeds to step (208).
Step 203 stops the image stabilization operation and returns to step (203).
) Return to Then, if the switch SWI is turned on, the position of the correction optical system is initialized, that is, centered, and image blur prevention is started again from step (204).

FIG. 8 shows the release prohibited area realized in the above flow, and the coordinate axes etc. correspond to those in FIG. 4. That is, with respect to the movable range ±dmax of the correction optical system 33 for both the i and j axes, if the displacement dL of the correction optical system exceeds ±dcr, release is prohibited, so the area indicated by hatching in the figure is prohibited to release. It becomes an area.

FIG. 9 is a control flow diagram of the in-lens microcomputer LCPU.

When the power to the camera CMR side is turned on, the lens L is connected to the camera CMR side via the mount contact between the lens and the camera.
Power supply starts to the NS side, and the microcomputer LCPII inside the lens
starts execution of a predetermined sequence program.

While the ON signal for switch SW1 is not received from the camera CMR in step (302), all control flags and variables set in the RAM in the lens microcomputer LCPtl are cleared and initialized in step f303). .

When the switch SWI on signal is transmitted from the camera CMR, the process moves to step (304), where "communication 1
”. This is the step (004) in Figure 5.
Compatible with "Lens Communication 1", the microcomputer L inside the lens
Sends various information stored in the ROM of CPtl to the camera's microcomputer CCPυ.

The in-camera microcomputer ccpu performs focus detection calculations and sends a lens drive command, which is received in step (305), and in the next step (306), the focus adjustment lens FL is
Performs drive control of NS.

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

During step (306), when communication of an ON signal for switch SW2 is received from camera CMR, an interrupt is permitted and the process moves to step (311).

The on signal of switch SW2 is sent by the microcomputer IC for image blur prevention.
PU also receives the flag LFLG regarding the position of the correction optical system ILNS, so it is received in step (3121) and the flag LF is sent in the next step (313).
Send LG to the camera's microcomputer ccpu.

In step (314), it is determined whether a release permission signal (in this embodiment, a narrowing down command) has been received from the microcomputer CCPU in the camera, and if NO, the process returns to step (312).

If it is determined in step (3+4) that the release permission has been transmitted, that is, the narrowing command has been transmitted, step (315)
The diaphragm stepping motor DMTR is driven to perform the diaphragm operation.

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

In step (31?), it is recognized that the narrowing down has been completed, and this is sent to the microcomputer ccpu in the camera.

In response to this, the camera CMR performs shutter control and starts film exposure.

Next, the microcomputer ccpu in the camera transmits an aperture opening command, and when this is received in step (318), the aperture opening operation is performed in the next step (319).

When the aperture opening operation is completed, a completion signal is sent to the in-camera microcomputer ccpu in step (320), and the process returns to step (302).

The above flowcharts shown in FIGS. 5 to 9 will be summarized again.

When the in-camera microcomputer ccpu recognizes that switch SW1 is on, it sends the SWI on signal to the in-lens microcomputer LCPU.
and sends it to the image blur correction microcomputer 1CPU.

By turning on switch SW1, the camera's microcomputer ccpu
performs exposure calculation and focus detection calculation, and microcomputer L inside the lens
In response to this, the CPU drives the focusing lens.

Further, the image blur correction microcomputer 1CPU starts an image blur correction operation.

When the interrupt of the ON signal of the switch SW2 occurs, the image blur correction microcomputer lCPU sends a flag LFLG regarding the position of the correction optical system 33 for image blur correction to the camera microcomputer CCPt1 via the lens microcomputer LCPU, and rLFLG. = If OJ, the camera's microcomputer ccp
u starts the release operation, and if rLFLG=IJ, prohibits the release and waits until rLFLG=OJ. If rLFLG does not become OJ even after a predetermined period of time has elapsed, the release is canceled.

As a result of the above operation, while monitoring the flag LFLG, the release is prohibited when the focus shift is large, and the inhibition is canceled when the focus shift becomes small.

In the first embodiment, when the focus shift is large, the release is prohibited and the camera waits until the focus shift becomes small, so it is possible to take pictures without problems with out-of-focus and blurring, but there is a risk of missing a photo opportunity. Therefore, in the second embodiment, when the focus shift is large, the correcting optical system ILNS is centered before the release is performed, so that an increase in the release time lag can be prevented.
Never miss a photo opportunity.

FIG. 10 shows the flow in this second embodiment, which is different from the flow in FIG. 7 in the first embodiment with steps (217) and (
The only difference is that (221) and (222) are newly inserted between 218). Therefore, only this changed part will be explained.

The displacement of the correction optical system ILNS is large, and the step (211
) or (212), "1" is stored in the flag LFLG in step (216), and rL is stored in the lens microcomputer LCPLI in step (217).
FLG=IJ is transmitted and the release is held.

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

Then, the output of the integrator INT2 becomes d=o at that moment, so 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 return gain of the feedback loop constituted by the operational amplifier AMP and the drive circuit IDR, but it is usually possible to perform centering in several tens of m5ec.

In step (222), a delay timer prevents the process from proceeding to the next step until the centering is completed. Here, the delay time is set to 100 m5ec.

Next, in step (218), it is determined whether a release cancel signal has come from the camera CMR, and if NO, the process returns to step (211).

Note that in this second embodiment, once the centering operation is performed, it is normally unlikely that the determination will be NO again when returning to steps (211) and (212). That is,
Normally, the flow of steps (216) to (218) can be branched to step (213) by passing only once, so
The increase in release time lag is suppressed to roomsec.

As described above, in the second embodiment, when the switch SW2 is turned on, if 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 started immediately (
This is the same as the first embodiment).

On the other hand, when either the i or j axis is outside the allowable displacement dcr, the centering operation is performed and then the release operation is performed. Only in this case, the release time lag will be slightly longer, and the framing of the shooting screen will change slightly due to centering, but the out-of-focus can be corrected.
The effect is great.

Said 1st. In the second embodiment, the out-of-focus problem occurred due to a problem with the support structure of the correction optical system ILNS, but as the amount of displacement of the correction optical system ILNS increases, pure optical problems also occur. That is, increases in multiple aberrations such as astigmatism and distortion, unbalance, and unbalance in the amount of light on the image plane. Therefore, even with a configuration in which the correction optical system can be displaced completely perpendicularly to the optical axis, as disclosed in Japanese Unexamined Patent Application Publication No. 63-155038 by the applicant, the above-mentioned aberration problem occurs, and when the displacement is large, it is necessary to prohibit the release. becomes.

In addition, in a device that performs image blur correction using a variable apex angle prism described in JP-A-2-41757, etc., as the apex angle of the prism is increased to strengthen the optical axis eccentricity, chromatic aberration occurs. becomes larger. Even if you release the camera in such a case, you will not be able to obtain a good photograph, so it is preferable to prohibit the release. FIG. 11 shows the configuration of this third embodiment.

In this embodiment, instead of the correction optical system ILNS, a variable apex prism VP is arranged at the tip of the lens as an optical axis decentering means for image blur correction. Variable vertex angle prism vP is 2
Composed of two transparent parallel flat plates, an accordion-shaped film, and an enclosed liquid.The tilting of the flat plate on the subject side corrects vertical (pitch) blurring, and the tilting of the flat plate on the lens side corrects horizontal (yaw) blurring. can.

In FIG. 11, PACT is an actuator that tilts and drives the variable apex angle prism VP, PSD is a position detection sensor that detects the prism tilt angle, that is, the optical axis eccentricity, PDR is a drive circuit that drives the actuator PACT, and AMP is an operational amplifier. . The infrared light emitting diode IRED and slit SLT are omitted, and the drive system in one direction is also omitted. These configurations and image blur correction principles are basically the same as in the first embodiment, and detailed explanations will be omitted.

FIG. 12 shows a flowchart in the third embodiment.

In this flow, steps (211) and (212) are replaced by (231) in the flow of the second embodiment in FIG.
, (232), only the changes will be explained.

In Fig. 11, the optical axis decentering direction for image blur correction is obtained by combining the vertical (pitch) and horizontal (yaw) directions, so the vertical direction is the y-axis, and the horizontal direction is the x-axis. The amount of optical axis eccentricity due to prism action is dLy, dL
Let it be x. Then, in step (231), the register dL
The value dLxy← x +dLy is stored in xy.

In step (232), the above value dLxy and the allowable displacement dc
Determine the size of r. Here, the permissible displacement dcr is the optical axis eccentricity limit at which image deterioration, in this embodiment, the influence of chromatic aberration due to the variable apex angle prism (P) can be tolerated. And l dL
If xy l≦dcr, it is determined that the image deterioration is tolerable and the process proceeds to step (213), and if dLxyldcr, the image deterioration is determined to be large and the process proceeds to step (216), where "1" is stored in the flag LFLG and the release is prohibited. , In step (221), the integrator T2 is reset and the variable apex angle prism P is centered.

FIG. 13 is a diagram showing the release prohibited area in this third embodiment, and is a diagram similar to FIG. 8.

The amount of optical axis eccentricity due to the variable vertex angle prism VP is X.

Although it is possible to release up to ±dmax in the y direction, the area outside the radius dcr centered on the origin, shown by hatching, is a release prohibited area.

According to each of the embodiments described above, when the amount of optical axis eccentricity due to image blur correction exceeds a predetermined value, it is assumed that image deterioration due to defocus or aberration exceeds the allowable limit, and release is prohibited, and the above-mentioned optical Since release is permitted when the amount of shaft eccentricity is within a predetermined value, image blur correction can be performed well and photographs without image deterioration can be obtained.

Furthermore, if a release command is issued when the amount of optical axis eccentricity exceeds a predetermined value, the correction optical system is centered before release is permitted, thereby minimizing the increase in release time lag. did it.

(Effects of the Invention) As explained above, according to the present invention, when the displacement detection means detects that the displacement of the correction optical system is outside a predetermined range, the release operation by the release control means is prevented. Since the release prevention means is provided to prevent the release operation when the correction optical system is displaced to the extent that image deterioration is expected, blurring is appropriately corrected and defocusing is prevented. It becomes possible to obtain photographs without image deterioration such as.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the first embodiment of the present invention, FIG. 2 is a perspective view of the correction optical mechanism, FIG. 3 is a diagram showing the drive locus of the correction optical mechanism, and FIG. 4 is the same. FIGS. 5 to 7 and 9 are flowcharts illustrating the movement of the focus, FIG. 8 is a diagram illustrating the release prohibited area, and FIG. FIG. 11 is a block diagram showing the third embodiment of the present invention, FIG. 12 is a flowchart showing the image blur correction operation, and FIG. 13 is a release prohibition area. FIG. 14 is a block diagram schematically showing a general image blur correction device. ACC, li, lj... Accelerometer, lNTl,
INT2...Integrator, ILNS...
Correction optical system, CCPU...in-camera microcomputer,
LCPU・・・・・・Microcomputer in the lens, ICP[]・
...Microcomputer for image blur correction, PSD...
Position detection sensor, SNS... Focus detection sensor, IRED... Infrared light emitting diode, IMTR
...Motor, IDR...Drive circuit, v
P...Variable vertex angle prism, PDR...
drive circuit.

Claims (4)

[Claims] (1) A correction optical system for decentering the optical axis of the imaging optical system, a vibration detection means for detecting a shake state of the imaging optical system, and driving the correction optical system based on a signal from the vibration detection means. a displacement detection means for detecting the displacement of the correction optical system and generating a displacement signal; an image blur correction means for correcting image blur; In a camera with an image stabilization function, which is equipped with an exposure calculation means for calculating a shutter speed and a release control means for controlling a release operation based on the generation of a release start instruction signal, the displacement of the correction optical system is determined by the displacement detection means. A camera with an image stabilization function, characterized in that a camera with an image blur correction function is provided with a release prevention means for preventing the release operation by the release control means when it is detected that the image is out of the range. (2) The image blur correction function according to claim 1, further comprising a release means for releasing the release operation prevention by the release prevention means when the aperture value calculated by the exposure calculation means is other than a predetermined value. camera. (3) After determining whether the release prevention means has blocked the release operation, the correction optical system is returned to within a predetermined range via the drive means, and when the return operation is completed, the release prevention means is released from blocking the release operation. 3. The camera with an image blur correction function according to claim 1, further comprising means for correcting image blur. (4) a vibration detection means for detecting a shake state of the imaging optical system; and a driving means for driving a correction optical system for decentering the optical axis of the imaging optical system based on a signal from the vibration detection means;
An interchangeable lens for a camera, comprising: displacement detection means for detecting displacement of the correction optical system and generating a displacement signal; and output means for outputting information regarding the displacement of the correction optical system.