JP2814238B2 - Ballif local lens controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Technical field   The present invention relates to a varifocal lens control device.
More specifically, a variable power lens group and a variable power lens
A variable power optical system consisting of
The relationship between the separation and the extension amount of the focusing lens unit in the optical axis direction changes.
Any first position in the magnification range that differs at the magnification position in the magnification range
Variable power to update from the focal length of the image to an arbitrary second focal length
Vari-focal lens which causes image shift due to work
Related to the control device. (B) Conventional technology   The zoom lens position is the same as the image formation position even when zooming.
No deviation (so-called focus shift or defocus)
This eliminates the hassle of adjusting the focus for each zooming operation.
Easy operability with no aperture, but open aperture compared to single focus lens
Because the F-number is dark, for example, a single-lens reflex
Some skill in adjusting the focus (focusing operation) with the indah
Is required. In recent years, AF has been adopted for cameras,
The original mobility of the zoom lens
Can be controlled, and the operator (user) can
Focus on composition decisions
, Greatly improved operability.   Generally, focusing (focusing operation) of the zoom lens
Focusing lens group installed in a part of the variable power optical system
The move has been made. And the zoom lens
Is for the same subject distance in all zoom ranges.
The moving amount of the causing lens group is almost the same (hereinafter,
Is referred to as “equivalent movement”).
The moving distance of the focusing lens group
(Distance ring), while being located adjacent to it
Just attach an index to the fixed ring to
It is not necessary to change the subject distance scale according to
There are advantages. However, the lens structure of the variable power optical system described above.
The inner focusing method and the
And for rear focusing zoom lenses
Optical design under the condition that equal movement of
In this case, there is a problem that the lens configuration becomes complicated. Sa
Furthermore, the amount of movement of the focusing lens group on the wide-angle side
(Delivery amount) becomes unnecessarily large.
In addition, the outer diameter of the lens increases due to this,
There is a problem that the weight of the lens and the lens barrel increases.   Therefore, in order to solve these problems,
A varifocal lens with moving conditions has already been proposed.
However, this varifocal lens has the zoom
If you perform a zoom operation corresponding to the zooming operation of
There is a problem that an imaging position shift occurs. This problem
The solution is to change the components that make up the varifocal lens.
A part of the magnification optical system is used as a focusing lens
It is configured to enable vertical focus drive, and
Image shift (hereinafter sometimes referred to as “shift”)
The focusing lens group is calculated based on the calculation result and based on the calculation result.
If the position is corrected, the operation is virtually the same as a zoom lens
It is thought that sex can be obtained.   Now, if you want to perform automatic shift correction like this,
In order to set the desired focal length, change the magnification
Variable magnification drive unit driven by a motor, etc., and the above-mentioned focusing lens group
Focus drive unit that drives the
Detects the currently set focal length as an absolute value such as voltage
For example, a focal length detector such as a potentiometer
The current position of the focusing lens group is also detected as an absolute amount such as voltage.
Focus position detection, such as a potentiometer
What is called analog by analog control using an output device
It is thought that it can be realized by configuring a servo mechanism.
Can be   However, the above varifocal lens is
The focus position of the focusing lens group on the object depends on the focal length.
The trajectory of this change depends on the focal length (focal length detection
Is a hyperbola with the output of the
It is difficult to realize this with a robot mechanism (analog operation).
It would be extremely complicated and expensive
U.   The drive motor for driving the focusing lens group is analog
When controlling, do not use expensive and high-precision circuit members
Hunting is likely to occur, making it difficult to speed up control.
It is difficult.   In recent years, automation of camera operation has been advanced, and these various complicated
Microphones for efficient and comprehensive control of
Computers are frequently used. In other words, MicroCo
In a computer-based camera, the center of control is of course
It is digitized even around it, for example
Distance measurement data output from the distance measurement unit, which is the main part of the automatic focusing device
Data has also been digitized. Therefore, the above varifor
Of course, the above-mentioned automatic focusing device can be provided on the cull lens itself.
Yes, but you can use an autofocus device already built into the camera.
Sharing is economically advantageous. However, like this
Varifocal
If the lens control system is performing analog processing,
When the interface between the camera and the camera body becomes complicated,
Problem arises.   The control system of the varifocal lens is digital.
However, the following problems remain. That is,
Lens group is in the in-focus position, and perform zooming operation from this state
In the case, the control system of the varifocal lens is
Move the focusing lens group along the line to maintain focus
In general, for example, the image in the viewfinder
Focusing operation for correction to make the angle change natural
(Hereinafter referred to as “shift operation”) and a change in focal length
The focal length should be reached while alternately repeating
You. Each time the shift operation is repeated alternately in this manner,
Next extension of the focusing lens group up to the focusing position for each time
Needs to be calculated. However, this next delivery amount
The reference value used as the reference for calculation is updated each time,
Position detection error of lens group and focusing lens group, calculation error
Errors such as differences and shift control errors gradually accumulate.
However, the accuracy of shift control is reduced accordingly.
I will. (C) Purpose   The present invention has been made in view of the above circumstances, and
The common purpose is to make it cheap and simple.
Updating the focal length of the varifocal lens
A flash that can correct the imaging position shift with high accuracy and at high speed
An object of the present invention is to provide a focal lens control device.   Further, the first individual object according to the present invention is the first object of the present invention.
An inexpensive and simple configuration which is an object unique to the first invention.
However, the position of the focusing lens group can be controlled at high speed and with high precision.
Automatic focusing and correction of image position shift
And achieve cost reduction by sharing parts.
To provide a variable focal lens control device
Therefore, the individual second object is an object peculiar to the second invention.
Even if the shift correction accompanying the magnification operation is repeated,
Position detection error of lens group and focusing lens group, maximum extension
Calculation errors of the amount, proportional constant, and image position offset correction amount, etc.
Accuracy of the above imaging position shift without accumulating errors
To provide a varifocal lens control device that can correct well
It is to be. (D) Configuration   The objectives described above, namely the common objective and the individual primary
In order to achieve the object, the first invention (claims)
The invention described in (1) is a variable magnification lens disposed on the same optical axis.
The zoom optical system consists of a lens group and a focusing lens group.
The object distance and the extension amount of the focusing lens unit in the optical axis direction.
Is different at the magnification position within the magnification range, and within the magnification range.
From any first focal length to any second focal length
Varifos that cause image position shift due to new scaling operation
The focal length of the zoom lens
Double drive means and a focus drive hand for driving the focus lens group
A step, a variable power control means for controlling the variable power driving means,
The variable power lens group and the focusing lens group on the optical axis
Each absolute position is detected, and the focus corresponding to the absolute position is detected.
Outputs point distance information and focusing lens group position information
Lens absolute position detection means and absolute detection of this lens group
Distance information and focusing lens position output from the means
Absolute image position deviation correction
The corrected in-focus position corresponding to the position is calculated by a predetermined
The calculated focus correction absolute position calculation means and the distance to the subject
From the current position of the focusing lens group to the expected focus position
Defocus amount as a relative amount, which is the amount of deviation to
Output distance measuring means and corrective focus corresponding to the absolute position
The position is shared with the defocus amount output from the distance measurement unit.
The number of driving pulses of the focusing drive means
Absolute / Phase converted to the amount of movement as a relative amount corresponding to
Pair conversion means and the amount of movement of the focusing lens group on the optical axis
Is detected as the relative amount.
Relative position on the optical axis with a higher position resolution than
Relative movement like a photo interrupter that detects the amount of movement
Quantity detecting means and the default value output from the distance measuring means.
Output from the absolute / relative conversion means
Upon receiving the movement amount, the relative movement amount detection means
Receiving the force and based on the defocus amount for the subject.
The focus lens at the planned focus position or the corrected focus position.
Focusing control for controlling the focusing driving means to drive the lens group
Means, any first focal length within said variable power range.
By updating the focal length from to any second focal length
Automatically and accurately corrects the resulting imaging position shift
It is characterized by having been constituted as follows.   Further, the focusing by the focusing control means in the first invention is performed.
The position control of the focusing lens group
The focal length information from the absolute position detecting means changes by a predetermined amount
It is desirable to do it every time.   In addition, during the focus correction drive,
It is desirable to do.   To achieve the common objective and the individual secondary objective described above.
Therefore, a second aspect of the present invention, in which the elements of the first invention are used as main components,
Ming (the invention described in claim 4) has the same optical axis.
It consists of the variable power lens group and the focusing lens group
Variable magnification optical system, the subject distance and the focusing lens group
The relationship with the extension amount in the optical axis direction depends on the magnification position within the magnification range.
Different and arbitrary from any first focal length within the zoom range
Is changed to the second focal length by the zooming operation.
In a varifocal lens that causes displacement,
Variable magnification driving means for driving a lens group, and the focusing lens group
The focus driving means for driving the
Variable power control means, the variable power lens group and the focusing
The position of the lens group on the optical axis is detected to obtain focal length information and
And the displacement of the focusing lens group from infinity
Lens group position for outputting focusing lens group position information
Detection means and output from the lens group position detection means
Based on the focal length information, the
The repetition of the focusing lens group from infinity to the shortest focusing distance
Maximum feeding amount calculating means for calculating the feeding amount; The output of the maximum feeding amount calculating means and the position of the focusing lens group
Proportional constant calculating means for calculating a proportional constant from a ratio of information;
This proportionality constant and the maximum extension amount and the focusing
Correction of imaging position shift by receiving lens group position information
The amount of movement of the focusing lens group to the corrected focusing position where the correction is made
And the driving direction, respectively
Focus correction calculation means for calculating the direction, and the correction focus amount
And the corrected focus position based on the corrected focus direction.
Controlling the focusing drive means to drive the focusing lens group
Focusing control means, and the first update of the focusing distance.
Immediately before performing a new focus and newly focusing the above focusing lens group
Immediately before updating the focal length after setting the position
To perform the calculation processing of the proportional constant calculation means.
It is characterized by having achieved.   Further, the focusing by the focusing control means in the second invention is performed.
The position control of the focusing lens group
The focal length information from the position detecting means changes every predetermined amount.
It is desirable to do.   In addition, during the focus correction drive,
It is desirable to do.   Hereinafter, an embodiment of the present invention will be specifically described with reference to the accompanying drawings.
Will be described.   FIG. 1 shows a varifocal lens control device according to the present invention.
FIG. 2 is a block diagram showing a configuration of one embodiment of the device. In FIG.
Here, 1 is the optical axis of the variable power optical system, and 2 is along this optical axis 1.
Movably disposed on the optical axis 1 to move the zoom optical system.
2a, 2b, 2c, 2d, and 2e
A first group lens composed of a single lens or a plurality of lenses,
Second lens group, third lens group, fourth lens group, and fifth lens group
It is a group lens. Then, the fifth group lens 2e is focused.
A focus lens group 3 is formed as a lens group.
Including the fifth lens group 2e, the first lens group 2a to the fifth lens group
The variable power lens group 2 is constituted by the lens 2e. In addition, strange
The total focal length of the variable power optical system comprising the double lens group 2 is
F is the film surface. 4 is the focal length of the entire system
f is the telephoto side focal length as the longest focal length (hereinafter simply referred to as
Wide angle as shortest focal length from "tele side"
Side focal length (hereinafter simply abbreviated as “wide side”)
In order to set an arbitrary focal length between
Variable magnification motor Mz as variable magnification drive means to be driven and shown
Variable magnification drive unit consisting of a mechanism that does not work, 5 is close from infinity
At infinity on the optical axis 1 corresponding to the subject distance to
Position) to the shortest shooting distance position (hereinafter referred to as the "closest position").
The fifth group lens 2e,
Focus lens driving means for driving the focusing lens group 3.
Focus motor M_FAnd four
The scum drive units 6 and 7 are each provided with the focus lens.
Driven by the focus driving unit 5 together with the lens group 3,
Among them, 6 is obtained by rotating the slit disk 6a.
From the photo interrupter 6b
And the relative movement of the focus lens group 3 on the optical axis 1
Focus as relative movement amount detection means for detecting movement amount
The counter and 7 are absolute positions of the focusing lens group 3 on the optical axis.
Voltage in proportion to the focusing lens group position information
Focus position information S_XLens group position detection hand that outputs as
Step (hereinafter simply referred to as "absolute position detection means" or "lens
Focusing lens which is a part of
Group position detector (hereinafter abbreviated as “FPM”), 8 is variable magnification
Driven by the variable-power driving unit 4 together with the lens group 2, the variable-power lens
Relative to the absolute position on the optical axis of group 2 or the focal length f of the entire system
Output the example voltage as focal length information Zp, FP above
Focal length that composes the lens group absolute position detection means with M7
Detector (hereinafter abbreviated as “ZPM”), 9 is the above focal length
After receiving the information Zp and performing A / D conversion,
Of the focus lens group 3 from the position to the closest position
Maximum feeding amount calculating means for subtracting (that is, feeding amount) Fpm
As the maximum feeding amount calculation unit, and 10 is the maximum feeding amount calculation unit.
9 output Fpm and FPM7 focus position information (focus lens
Receiving the output Sx as the group position information) and A / D
After conversion, these ratios are calculated, and the proportional constant Cf described below is calculated.
Proportional constant operation as proportional constant operation means to output p
Unit 11 receives and focuses on the three outputs Fpm, Cfp and Sx
As the focus correction calculation means for calculating the correction amount Dfp for
This is a focusing correction calculation unit. Note that the maximum feed amount calculation unit 9,
The proportional constant calculation unit 10 and the focus correction calculation unit 11 are also provided.
The overall correction calculation unit as the focus correction absolute position calculation means
Make up 12. Therefore, the total correction calculation unit 12 calculates
The correction focus position as the absolute amount to be
Content. 13 is the absolute amount of this correction amount Dfp.
Absolute to convert to positive quantity Drv / Absolute /
The relative conversion unit 14 measures the distance to the subject and
Focus motor M to position_FRelative to the rotation speed of
Distance measuring unit that outputs the defocus amount Drx as an amount, 15 is
The output Dfc of the focus counter 6 and the relative correction amount D
rv or the defocus amount Dfx, respectively,
The correction focus position corresponding to the relative correction amount Drv or the default
Focus lens at the expected in-focus position corresponding to the focus amount Dfx
Controls the focus drive unit 5 to drive the lens group 3
A focus control unit as focus control means,
17 is an externally operable push button that activates the scaling operation.
Variable power switch as a starting means consisting of
16 is a magnification up switch (hereinafter simply "up switch")
17) is a magnification down switch (hereinafter simply "down"
Switch)), 18 are these up, down switch
Switches 16 and 17 to determine the rotation direction of the magnification motor Mz.
Drive direction judgment that outputs start signal (STR) after setting
Section 19 receives the start signal STR and the output Fpm to drive the variable magnification
A scaling control unit as scaling control means for controlling the unit 4;
You. Note that + V indicates the power supply, and the input / output
Only the number is shown.   In this case, the focus counter 6
Cas motor M_FOutput Dfc per rotation of 16
It is configured to output the luz.   Further, the maximum feeding amount calculation unit 9 adds the focal length information Zp to the
Focus lens group 3 from the ∞ position to the closest position
Is the maximum feed amount of Fpm, and is unique to the lens of the zoom lens group 2.
Is the constant of C₁, C_Two, C_ThreeAnd when   Fpm = ｛C_Two/ (Zp + C₁)｝ + C_Three                (1) It is configured to execute a certain operation.   The above constant C_Two, C_ThreeIs the subject distance D is a parameter
ing. Therefore this constant C_Two, C_ThreeIs the closest subject distance D₀
Contains.   Further, the proportionality constant calculation unit 10 sets the output as Cfp, and
Focus position information Sx immediately before performing the
Let the large feed amount Fpm be S (i) and Fp (i), respectively.
You.   Cfp = S (i) / Fp (i) (2) It is configured to execute a certain operation.   The focus correction calculation unit 11 sets the output as Dfp,
Maximum feed amount corresponding to focal length information Zp at the time to be corrected
If Fpm is Fp (e),   Dfp = {Cfp · Fp (e) / 256} −S (i)) (3) It is configured to execute a certain operation.   The output Zp of ZPM8 is Zp = 255 on the tele side,
On the wide side, Zp = 0, while the output Sx of FPM7
Is Sx = 0 at the ∞ position and at the closest position on the tele side.
Are configured so that Sx = 255.   Fig. 2 shows the zoom mode, macro mode and storage mode.
In each mode of the variable power lens group 2 in FIG.
It is a cam diagram which shows each movement.   In FIG. 2, reference numerals 20 to 24 denote the first lens group 2a, respectively.
-Fifth lens group 2e performs zooming, macro, and storage operations
Cam line showing the trajectory when moving by the work, especially the cam
Line 24 is the locus when focus lens group 3 is at position ∞
24a indicates that the focus lens group 3 is also in the closest position
The cam line of the fifth lens group 2e showing the trajectory when
Tele position indicating the position on the tele side, 26 indicates the position on the wide side
Wide position. 25a and 26a are
B position and storage position.   FIG. 3 shows a specific example of a cam groove corresponding to the cam diagram of FIG.
It is a development view which expands and shows a target shape.   In FIG. 3, 27 to 31 correspond to the cam wires 20 to 24 in FIG.
The corresponding cam grooves are formed on the cam frame,
32 to 35 are formed in a fixed frame, and each of the first group lens 2
a, second group lens 2b, third group lens, and fifth group lens 2
c, 2e, and the fourth group lens 2d are respectively guided in the optical axis direction.
This is a line cam groove. 25 and 26 are text as described above.
Position and the wide position.
Instead of being in a straight line as in a cam diagram,
In the circumferential direction by each cam groove 27-31 so as not to cause interference
It has been shifted accordingly. That is, the tele position 25 in FIG.
The wide position 26 is equivalently shown.   FIG. 4 shows an overall correction operation of the embodiment shown in FIG.
It is a diagram for explaining the principle of the operation of the unit.   In FIG. 4, the total focal length f to be set and the focus
Extension amount (movement) of the lens group 3 corresponding to the subject distance D
Amount) for each typical subject distance D, and the vertical axis indicates the total system distance.
The horizontal axis indicates the change in focal length f and the in-focus position for infinity
Indicates the extension amount of the focus lens group 3 with reference to
You. In this example, the tele position is f = 135 mm.
The wide position is f = 35 mm. 36-38
When the subject distance D is ∞, 3.0m and the closest distance (1.2m)
In the focus curve, as described above, the constant C in equation (1)_Two, C_ThreeParame
The object distance D, which is the data, is set to ∞, 3.0m, 1.2m.
The focus level for changes in focal length information Zp
Of the amount of feeding of lens group 3 from the infinity position to the in-focus position
Is obtained. Therefore, the focusing curve 38 has the maximum extension
This is the closest focusing curve that is
The maximum amount of movement up to the closest focusing curve 38 is
Fpm. Zp (i), S (i) and Fp (i)
The focal length information (the first focal length) immediately before performing the zooming operation, respectively.
Separation information) Zp, focus position information Sx, and Zp (i) above
From the focusing curve 36 of ∞ to the closest focusing curve 38 at
Momentum Fpm (maximum feed amount), and Zp (e), Fp
(E) and Dfp, respectively, the operation of the variable-power
Focal length information at the time of correction from the start (second focus)
From the focusing curve 36 in Zp (e).
Compensation for the amount of movement up to the focus curve 38 and the focus movement
It is a positive amount.   That is, Zp immediately before the scaling operation, that is, Zp = Zp (i)
Feeding amount Fp (i) of lens and current position of focus lens group 3
The ratio to the feeding amount S (i) up to the position is calculated by the above equation (2).
Zp after the end of the scaling operation, that is, Zp = Zp (e)
In the above, the focus lens group 3 is moved by the zooming operation.
If the camera is stationary (the focus operation is not performed during
S), S (i) is the same as S (i) above, and Fp (e)
Can be obtained by substituting Zp (e) into equation (1).
In other words, Dfp is unknown on Zp = Zp (e).
Then, using the proportionality constant Cfp obtained by equation (2), equation (3)
Thus, the unknown Dfp is obtained. This Dfp is
This is a correction amount as a contrast.   FIG. 5 is a diagram for explaining the operation of the embodiment shown in FIG.
In the graph, the same parts as those in FIG.
You.   In FIG. 5, 38a and 39 are Zp = Zp₁Each of the above
The points of intersection with the focusing curves 37 and 38, and 40, 42 and 44 are
Change of the focal length information Zp and its direction
Arrow showing S₁Is the value of the focus position information Sx at point 39, 41 and
And 41a are respectively Sx = S on Zp = Zp '₁Become a virtual straight line
And points 43 and 45 that intersect with the focusing curve 37
In the operation, the change amount and direction of the focus position information Sx
Arrows indicating 46 and 46a indicate Zp = Zp_ThreeUpper Focusing Curve 37
And points 47 and 49 intersect with 38 and 38
And arrows indicating the amount of change in Zp and its direction.
Changes in focus position information Sx during magnification down operation
It is a dashed arrow showing the quantity and its direction. Arrows 43, 48
Are both Zp = Zp_TwoParallel to the top.   Now, the operation of the present embodiment configured as described above will be described.
You. First, the scaling operation, which is the main part, and the accompanying
Before explaining the shift operation to correct the focus movement,
About the operation of automatic focusing in a general automatic focusing device
State. Now, as the initial position, the focus lens group 3 is
For example, it is assumed that it is at a close position. The subject distance D is D
= 3.0m. Here, the distance measurement switch that starts the distance measurement operation
Switch or the release switch (
(Not shown), the distance measuring unit 14 operates.
Is started, and the distance to a subject (not shown) is measured.
Then, this measurement result is_FRotation speed
Output as the converted defocus amount Dfx and receive this
Focus control unit 15 focus motor M_FRotated
Monitor the output Dfc of the focus counter 6 and
The position where fc = Dfx is determined as the in-focus position and
Focus motor M_FTo stop. Corresponding to Fig. 5, 3.
The focusing lens group 3 is set on the focusing curve 37 of 0m
Become. That is, the focus lens group 3 is
From the point 38a to the point 39.   Now, regarding the scaling operation and the shift operation,
This will be described with reference to the flowchart of FIG. 7 and FIG.
Now the focus lens group 3 is at 3.0m as described above
It is assumed that the camera is at a position where the subject is in focus. Therefore Figure 5
Is on the focusing curve 37 of.   First, we explain the magnification increase operation from the wide side to the tele side.
When the up switch 16 in FIG. 1 is pressed,
Therefore, the drive including the information on the zooming direction from the driving direction determination unit 18 is activated.
A signal (STR) is output and the flow chart in FIG.
Starts with START. In other words, first,
? Drives the state of the up switch 16 in the conditional branch of
The direction determination unit 18 checks. For now, branch to YES
However, if branching to NO, the next conditional branch is
Eun? Check the status of the down switch 17 with
Branch to NO if the down switch 17 is not operated
Return to the condition branch of “Multiply magnification?”
Repeat the same operation until either switch 16 or 17 is operated.
Is returning. Here, this operation loop is referred to as a “switch
Check loop ". By the way, the next "ZDR
= 1 ”, the drive direction determination unit 18 determines that the drive direction is
Direction, the start signal (STR) contains ZDR = 1 indicating this.
And outputs the result to the scaling control section 19. Next, "Zp read" and
In “Sx reading”, the maximum feeding amount calculation unit 9 sets the focus of the ZPM8.
Receives the output (Zp) as point distance information, performs A / D conversion, and
Example The constant calculation unit 10 uses the focus lens group position information of FPM7 as
Receives the output (Sx) and performs A / D conversion.
For example, as shown in FIG.₁And S₁Assume that One
It is assumed that the variable power lens group 2 is located at the round point 39. next
In the “maximum feed amount calculation”, the maximum feed amount calculation unit 9 uses the Zp₁
Is substituted into the above equation (1) to calculate the maximum feed amount Fpm.   In the next conditional branch "Update subject distance?"
From the focus operation, that is, in this case,
The subject distance set in the dynamic focusing operation (in the above example,
3.0m), the up and down switches 16 and 17 are operated
After that, it is checked whether or not the subject distance has changed.
In this case, the subject distance is still D = 3.0m, so
In the next “First magnification?”, The first magnification
Because it is an operation, branch to YES, and proportional in the next “Calculate proportional constant”
The constant calculation unit 10 also receives the maximum feed amount Fpm and calculates
Therefore, the proportional constant Cfp is calculated. That is, the above S₁S₁
= S (i) and the above Zp₁Fpm for Fpm = Fp (i)
Are substituted into equation (2) to obtain Cfp. Toes
According to FIG. 5, from the focusing curve 36 of ∞, Zp = Zp₁Up
Between the point 39 and the focusing curve 36 to the point 38a.
The ratio with the length is obtained. The flowchart of FIG.
Moves to the state shown in FIG. In addition, the "switch
The operation up to and after the "check loop" is called "initial setting operation".
Shall be called.   In the conditional branch "Continue scaling" in the flowchart of FIG.
In addition, the drive direction determination unit 18 includes an up / down switch
Check if 16/17 is pressed (ON state)
You. Now, assume that the up switch 16 is being pressed
(Hereinafter, this state is maintained until specified otherwise.
And). Therefore, branch to YES in the above conditional branch,
In the next “zoom lens group drive”, the zoom controller 19
Magnification in the direction of magnification increase with reference to ZDR = 1
The motor Mz is rotated. That is, the zoom operation starts. So
Zoom lens group 2 moves, and the output (Zp) of ZPM8 also points to the arrow.
It changes as shown at 40. However, FPM7 focus
Motor M_FIs not operating, the fifth group lens 2e is
Changes according to the cam wire 24 in FIG. 2 or the cam groove 31 in FIG.
(Moves), but is constant as the focus lens group 3.
Position and does not change depending on the magnification operation.
No. In the next "Zp reading", it is indicated by the arrow 40 in FIG.
Recent value Zp 'of focal length information Zp that has started to change in the direction
(The position of the point 41) is read by the maximum feeding amount calculating section 9, and the next
As described above in “Maximum dispensing amount calculation”, the Zp ′
The latest Fpm is calculated by substituting into the equation (1). Next `` Sx reading
Should not have changed, but A / D conversion
Considering the rounding error of the heat exchanger and mechanical backlash,
The focus correction calculation unit 11 reads Sx. Then, the next “correction amount
In "Calculation", the value is calculated by "Calculation of proportional constant" in FIG.
Fpm corresponding to Zp ′ is expressed as Fp (e) using the proportional constant Cfp
Sx = S₁= S (i)
Calculate the correction amount Dfp, which is an absolute amount, by substituting into equation (3).
You. Focus correction calculation in the next conditional branch “closest side?”
The unit 11 determines whether the focusing direction is the closest side or the right side. I mean
In this case, the zooming direction is the direction of magnification increase, as indicated by the arrow in FIG.
Since the direction is 40, the focusing curve 37
Driving the focus lens group 3 in the direction of the approaching arrow 43
It is determined that it suffices to branch to YES. And the next "MDR = 1"
In the equation, M means the driving to the close side together with the correction amount Dfp.
The focus direction information of DR = 1 is output. One of the main parts of the present invention
In the next “Relative correction amount calculation”, the absolute / relative change
The conversion unit 13 includes a focus counter 6 and a focus drive.
Let Ct be a constant determined by the specific configuration of the unit 6.
Execute the calculation of Drv = Dfp × Ct, and calculate the absolute amount of correction Dfp
Is converted into a relative correction amount Drv. Meaning of the operation of this main part
Is calculated from Zp, which is the position information of the zoom lens group 2.
Dfp, which is the amount of movement of the focus lens group 3
Focus motor M_FIs converted to the number of rotations.
However, while monitoring the output Sx of FPM7 using the correction amount Dfp,
It is theoretically possible to control the focusing lens group 3.
However, the actual movable range of the focus lens group 3 (∞
Position to the nearest position) is only a few mm
Position control within the camera by the correction amount (movement amount) Dfp and FPM7
It is actually very difficult to accurately perform
Even if it can be realized, extremely high precision FPM7 is required
Focus motor M which is disadvantageous in cost and_FSuspension
It takes time to control. Therefore, in this embodiment,
The correction amount Dfp is converted to the relative correction amount Drv
To increase the resolution and to control the position accurately and quickly
Was made possible.   On the other hand, recent cameras are equipped with an automatic focusing device.
There are many. Automatic focusing device in such an automatic focusing device
Function for varifocal lens shift correction.
If the members are shared, it is advantageous in terms of cost. This advantage
In order to utilize the points, in this embodiment, the correction amount Dfp is
The absolute / relative conversion unit 13 allows the distance measurement unit of the automatic focusing device to be used.
This is the same signal as the defocus amount Dfx output from 14.
Focus motor M_FOf relative amount converted to rotation speed
Data.   Now, returning to the flowchart of FIG.
Absolute / relative conversion unit 13
Indicates whether the relative correction amount Drv has exceeded a predetermined value (for example, Drv
≧ 20), and focus movement (shift)
Is monitored to see if the
You. And in this case, the zoom lens group 2 is still driven
The shift amount (the point 41 and the point 41a in FIG.
(Corresponding to the length of the interval) is also small, branching to NO,
Continue? , And the above operation is repeated. In addition, here
This operation loop is called the "shift amount monitoring loop".
And The variable power motor Mz continues to rotate, and the variable power
Group 2 passes through the point 41 from the arrow 40 in FIG.
Is driven in the direction of. And Zp = Zp_TwoDrv
= 20, the shift amount monitoring loop
From "Large out of focus?" Branch to YES.
The relative conversion unit 13 outputs the relative correction amount Drv and the above MDR = 1.
I do. Then, at the next “stop of variable power drive”, the variable power controller 19
Stop the variable magnification motor Mz, and set the relative correction amount Drv and
Upon receiving the focus direction information MDR = 1, the focus control unit 15
Focus motor M with "focus drive"_FRotated
And move the focus lens group 3 to the closest side, that is, in FIG.
In the direction of arrow 43. In FIG. 2, the cam wire 24
Corresponds to the direction toward the cam wire 24a. Next condition
In the “Correct focus position?”, The focus control unit 15
Calculates the output Dfc of the focus counter 6 and the relative correction amount Drv.
Compare them sequentially, branch to NO until they match, and
Return to “Focus drive” and drive the focus lens group 3.
Continue to work. Thereafter, the focus lens group 3 moves to the fifth position.
Move in the direction of arrow 43 shown in the figure, and
When it reaches, Dfc = Drv, so the above conditional branch is set to YES
Branch to focus mode
Data M_FTo stop. The operation up to this point is
In the first cycle of the shift operation, the flowchart of FIG.
The chart returns to the above-mentioned "Continue zooming?"
Move to control. It should be noted that the above "shift amount monitoring loop"
Note that the variable power drive stops and the focus drive stops.
The operation in the above is referred to as “correction focusing operation” so far.
You.   By the way, the operation of the second cycle is described in the above “shift amount monitoring
Movement of the zoom lens group 2 in the direction of arrow 44
Driven Zp = Zp_ThreeWhen the shift amount reaches a predetermined value at
The operation proceeds to the above-mentioned correction focusing operation. And the operation of this correction focusing operation
Assume that the up switch 16 is turned off during operation
Then, the correction focusing operation is continued, and the focusing is performed in the direction of arrow 45.
The lens group 3 is driven. After that, the focusing lens group 3
Reaching on focus curve 37 (position of point 46)
After completing the operation, return to the conditional branch "Continue zooming?"
In the drive direction that the up switch 16 is OFF
The determination unit 18 detects the signal, and the flowchart branches to NO to determine the next
Proceed to the subroutine “correction focusing operation”. This subroutine
The operation details of the correction focusing operation are the same as the above-described correction focusing operation.
However, in this case, the “zoom stop” has already been executed.
The variable magnification motor Mz is stopped, and the shift amount also becomes Drv = 0.
In the subroutine "correction focusing operation"
Does virtually nothing. That is, this subroutine
The up / down switch 16/17 monitors the above shift amount
What was prepared for the case of turning off the loop operation
It is. The flowchart of FIG. 7 is reached, and from here
Moving on to Fig. 6, the above "switch check loop"
enter. Press up / down switch 16/17
Since this is not done, the "switch check loop"
Operation is repeated. This completes the magnification up operation.
It's all over.   Now, now, the zoom lens group 2 and the focus lens group
3 is at point 46 in FIG. About the operation of magnification reduction
As mentioned, the operation is divided into two cases and only the main points are simplified.
explain. In the first case, the operation of reducing the magnification from point 46,
In the second case, after the subject distance D is updated once,
Operation.   In the first case, the current down switch 17 is pressed.
Then, in the flowchart of FIG.
Branch to "YES" in "ZDR"
= -1 ”means that the magnification direction is the direction of the magnification reduction.
Outputs the signal of ZDR = -1 to taste
In the "Update subject distance?" And "
? Is branched to NO to calculate a new proportional constant Cfp.
The same Cfp used during the previous magnification up operation.
(Remember) Moving on to Fig. 7, the scaling operation is started.
Then, in the shift amount monitoring loop, "closest side?"
Is branched to NO, and the focusing direction is determined to be ∞ side with “MD = -1”
You. In FIG. 5, the zoom lens group 2 is moved from the point 46 to the arrow 47.
When the shift amount exceeds a predetermined value, the above correction
Moves to focusing operation and drives focusing lens group 3 in the direction of arrow 48
To complete the first cycle. Similarly, arrows 49 and 50
Move, and when the down switch 17 is turned off,
The operation stops.   In the second case, the focus operation is performed to
Group 3 is moved from point 46 to point 46a, for example.
Suppose the camera is in focus. Then the down switch 17 is pressed.
Then, the switch check shown in the flowchart of FIG.
Branching in the group is the same as in the first case and the above initial settings
In the operation, "Subject distance update?" Branches to YES
Then, a new proportional constant Cfp is calculated. The following operation is the first
The description is omitted because it is the same as in the case of. This embodiment as described above
According to the above, the imaging shift caused by the zooming operation is corrected.
Correction amount D calculated as an absolute amount_Fp, focus
Sumota M_FFocus corresponding to rotation angle (number of pulses)
The relative correction amount Drv that can be compared with the count number of the counter 6
To control the position of the focus lens group 3
For example, a potentiometer such as FPM7
Resolution compared to using the
Is so high that high-precision position control can be realized.
Since there is no need for A / D conversion, high-speed control can be realized.
Can be. The focus mode is controlled by analog control.
Data M_FIf you try to control the stop position of
Causes long time for position control.
On the contrary, if you try to achieve high-speed control,
Requires a simple analog control circuit and cannot be put to practical use.
However, in this embodiment, high-speed control is performed with an inexpensive and simple configuration.
Can be realized.   Further, the absolute / relative converter 13 converts the correction amount Dfp into a
Output from the ranging unit 14 of the automatic focusing device built into the camera.
The same relative amount (digital amount) as the defocus amount Dfx
To convert to a relative correction amount Drv
Auto focus system built into the camera
Part of the position, ie focus counter 6, focus
Motor M_FAnd the focus control unit 15
Can be used for shift correction of
Configuration can be simplified as much as
Can be reduced.   Also, the proportionality constant Cfp is the value before the first scaling operation.
After performing point and focus operations, perform the next zoom operation.
Before the calculation, calculate and store the data,
Image position with subsequent update of focal length based on data
It is configured to compensate for the deviation, so that the
Shift control error, focus lens group 3, zooming
The position detection error of the lens group 2 and the calculation errors of the calculation units 9, 10, 11
The difference is not accumulated and the shift correction must be performed with high accuracy
Can be.   It should be noted that the present invention is not limited to the above-described embodiment,
Implementation of various modifications without departing from the gist
Is possible.   For example, in the flowchart shown in FIG.
Big? Is not limited to Drv ≧ 20, but the control speed and
And control stability, viewfinder observation image appearance, etc.
You can increase or decrease the number if you choose
Also, shift correction should be performed for each fixed magnification.
May be.   The output Dfc of the focus counter 6 is
Sumota M_FDon't limit to 16 pulses per revolution
If it is determined in the balance between control accuracy and control speed
Of course, the numerical value may be increased or decreased.   Also, do not stop the variable power drive during the correction focusing operation.
And both motors M_F, If there is no adverse effect on the power supply of Mz,
Movement may be performed in parallel.   Also, in the above embodiment, the self-contained camera
Defocus amount signal from distance measuring unit 14 in moving focusing device
Is configured to be able to automatically focus on
The present invention can be applied to a camera without a focusing device.
Is, of course. (E) Effect   As described in detail above, according to the first aspect, the focal length of the entire system
Varifocal lens-specific results that occur with renewal of separation
When correcting the image position shift, the amount corresponding to the absolute position
Outputs the corrected in-focus position data calculated from the distance measuring means
Signal common to the defocus amount as the relative amount
And a phase corresponding to the drive pulse of the focusing drive means.
It is converted to the amount of movement as a contrast amount, and this amount of movement is
Relative movement amount detection with higher position resolution than pair position detection means
Relative to the optical axis of the focusing lens group detected by the means
Focusing drive by focusing control means until it matches the moving amount
Since the means is controlled to drive, it is inexpensive and simple.
Despite the simple configuration, the position of the focusing lens group can be controlled at high speed.
It can be performed with high accuracy,
The defocus amount as the relative amount output from the distance means
Focusing lens group can be controlled by the same control system
The automatic focusing and the correction of the imaging position shift
Are realized together, and cost reduction is achieved by sharing parts.
be able to. According to the second aspect, the correction correction
The proportionality constant, which is the basis for calculating the focal position,
In addition, the ratio between the maximum extension amount and the focusing lens group position information is
Immediately before the first update of the focal length of the entire system and the focus
After setting the lens group to the new scheduled focus position,
Determined by calculation only immediately before updating the point distance
So that the shift correction accompanying the magnification operation is repeated.
The position of the zoom lens group and focusing lens group
Compensation for detection error, maximum feeding amount, proportionality constant and image position shift
Errors such as positive calculation errors are not accumulated.
Vari-focal recording that can accurately correct the imaging position deviation
A noise control device.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an overall configuration of an embodiment of a varifocal lens control device according to the present invention, and FIG. , FIG. 3 is a developed view showing an enlarged specific shape of a cam groove corresponding to the cam diagram, and FIG. 4 is a characteristic diagram of the device of the present invention shown in FIG. In particular, this is for explaining the operation of each arithmetic unit, and shows the relationship between the total system focal length f to be set and the extension amount Sx of the focus lens group corresponding to the subject distance D for each subject distance. FIG. 5 is a graph for explaining the operation of the embodiment shown in FIG. 1, and FIGS. 6 and 7 are flowcharts showing the operation sequence of the embodiment shown in FIG. 1 ... optical axis, 2 ... magnifying lens group, 2a to 2e ... first group lens to 5th group lens, 3 ... focus lens group, Fm ... film surface, 4 ... magnification driving unit, 5 Focus drive unit 6 Focus counter 7 Focus lens group position detector (FPM) 8 Focus processing detector (ZPM) 9 Maximum feed amount calculation unit 10 Proportional constant calculation unit, 11 Focus correction calculation unit, 12 Comprehensive correction calculation unit, 13 Absolute / relative conversion unit, 14 Distance measuring unit, 15 Focus control unit, 16 Magnification increase Switch (up switch), 17: Magnification down switch (down switch), 18: Driving direction judgment unit, 19: Magnification control unit, Mz: Magnification motor, M _F: Focus motor.

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G02B 7/08 G02B 7/10 G03B 3/12 G03B 13/36

Claims (1)

(57) [Claims] A variable power optical system including a variable power lens group and a focusing lens group disposed on the same optical axis, wherein a relationship between a subject distance and an extension amount of the focusing lens group in an optical axis direction is within a variable power range. In a varifocal lens which differs in the magnification position of and varies from an arbitrary first focal length to an arbitrary second focal length within the zooming range and causes an imaging position shift, A variable-power driving unit for driving; a focus driving unit for driving the focusing lens group; a variable-power control unit for controlling the variable-power driving unit; and the light of the variable-power lens group and the focusing lens group. Lens group absolute position detecting means for detecting each absolute position on the axis and outputting focal length information and focusing lens group position information corresponding to the absolute position, and output from the lens group absolute position detecting means Focal length information and A focus correction absolute position calculating means for calculating a corrected focus position corresponding to an absolute position at which the imaging position shift is corrected by receiving the focus lens group position information by a predetermined calculation formula; A distance measuring unit that measures and outputs a defocus amount as a relative amount that is a deviation amount from the current position of the focusing lens group to a planned focusing position, and measures the corrected focusing position corresponding to the absolute position. Absolute / relative conversion means for converting a signal common to the defocus amount output from the distance means and a movement amount as a relative amount corresponding to the number of driving pulses of the focus driving means, and the focusing lens A relative amount such as a photo interrupter for detecting the relative movement amount on the optical axis with a higher position resolution than the lens group absolute position detecting means, for detecting the movement amount of the group on the optical axis as the relative amount. Move Detecting means for receiving the defocus amount output from the distance measuring means or the moving amount output from the absolute / relative converting means, and receiving the output of the relative moving amount detecting means, the defocus amount for the subject Focusing control means for controlling the focusing driving means to drive the focusing lens group to a predetermined focusing position or the correction focusing position based on the first focal point, and an arbitrary first focal point within the zooming range. A varifocal lens control device configured to automatically and accurately correct an imaging position shift caused by a zooming operation for updating a distance to an arbitrary second focal length. 2. The position control of the focusing lens group by the focusing control means is performed every time the focal length information from the lens group absolute position detecting means changes by a predetermined amount from the start of the zooming operation. 2. The varifocal lens control device according to claim 1. 3. 2. The varifocal lens control device according to claim 1, wherein the variable power drive is performed in parallel with the focus correction drive. 4. A variable power optical system including a variable power lens group and a focusing lens group disposed on the same optical axis, wherein a relationship between a subject distance and an extension amount of the focusing lens group in an optical axis direction is variable. In a varifocal lens, which varies at a magnification position within a range and updates an imaging position by a zooming operation for updating from an arbitrary first focal length to an arbitrary second focal length within a zooming range, , A focusing drive unit that drives the focusing lens group, a scaling control unit that controls the scaling drive unit, and the zoom lens group and the focusing lens group. Lens group position detecting means for detecting respective positions on the optical axis and outputting focal length information and focusing lens group position information corresponding to the displacement of the focusing lens group from infinity, respectively; On the output from the detection means A maximum feed amount calculating means for calculating a feed amount from the infinity position to the shortest shooting distance position of the focusing lens group at the focal length based on the focal length information; and an output of the maximum feed amount calculating means and Proportional constant calculating means for calculating a proportional constant from the ratio of the focus lens group position information, and a correction unit for correcting the imaging position shift by receiving the proportional constant, the maximum extension amount, and the focusing lens group position information, respectively. A focus correction calculating means for calculating a moving amount and a driving direction of the focusing lens group to a focal position as a corrected focusing amount and a corrected focusing direction, respectively; Focusing control means for controlling the focusing driving means to drive the focusing lens group to the corrected focusing position, wherein the focusing lens is located just before the first update of the focal length and the focusing lens Varifocal lens control device according to claim only by being configured to perform arithmetic processing of the proportional constant calculating means immediately before the updating of the focal length after setting the group to the newly scheduled focus position. 5. 4. The method according to claim 4, wherein the control of the position of the focusing lens group by the focusing control means is performed every time the focal length information from the lens group position detecting means changes by a predetermined amount from the start of the zooming operation. 7. The varifocal lens control device according to claim 1. 6. 5. The varifocal lens control device according to claim 4, wherein the variable power drive is performed in parallel with the focus correction drive.