JP3450500B2 - Imaging lens controller - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup lens control device, and more particularly to a lens control device in a camera equipped with an inner focus type lens system.

[0002]

2. Description of the Related Art FIG. 5 is a diagram for explaining a simple structure of an inner focus type lens system which has been conventionally used.

In FIG. 5, 101 is a fixed first lens group, 102 is a second lens group for zooming, 1
Reference numeral 03 denotes a diaphragm, and 104 denotes a fixed third lens group. Reference numeral 105 denotes a fourth lens group, which is a lens group (hereinafter referred to as a focus lens) having both a focus adjustment function and a competition function for correcting the movement of the focal plane due to zooming. Reference numeral 106 denotes an image pickup surface of the image pickup element.

In the lens system configured as shown in FIG. 5, since the focus lens 105 has both a competition function and a focus adjustment function, the object image is focused on the image pickup surface 106 even if the focal lengths are equal. The position of the focus lens 105 depends on the subject distance.

By the way, when the subject distance is changed at each focal length, the position of the focus lens 105 for focusing on the image pickup surface 106 is continuously plotted as shown in FIG. Therefore, during zooming, if the locus shown in FIG. 6 is selected according to the subject distance and the focus lens 105 is moved along the selected locus,
Blur-free zoom is possible.

Further, in the front-lens focus type lens system, an independent compensating lens is provided for the variable power lens, and the variable power lens and the competitive lens are connected by a mechanical cam ring.

Therefore, for example, when a knob for manual zoom is provided on this cam ring and the focal length is manually changed, no matter how fast the knob is moved, the cam ring will follow this and rotate and change. The double lens and the compensating lens move along the cam groove of the cam ring. Therefore, if the focus lens is in focus, the above operation does not cause blurring.

In the control of the inner focus type lens system having the above-mentioned features, a plurality of locus information shown in FIG. 6 is stored in the lens control microcomputer in some form, and the focus lens and the variable magnification lens are stored. It is general that a locus is selected according to the position of, and zooming is performed while following the selected locus.

In this case, since the position of the focus lens with respect to the position of the variable power lens is read from the storage element and applied for lens control, it is necessary to read each lens position with a certain degree of accuracy.

In particular, as is apparent from FIG. 6, when the variable power lens moves at a constant speed or a speed close to it, the inclination of the locus of the focus lens changes every moment due to the change in the focal length.

This indicates that the moving speed and the moving direction of the focus lens change every moment. In other words, if the actuator of the focus lens is a step motor, the speed is accurate from 1 Hz to several hundred Hz. You will have to respond.

As an actuator that satisfies the above requirements, it is becoming common to use a stepping motor for the focus lens group of the inner focus lens system. The stepping motor rotates in perfect synchronization with the step pulse output from the lens control microcomputer and the step angle per pulse is constant.
It is possible to obtain high speed response, stop accuracy, and position accuracy.

Further, when the stepping motor is used, since the rotation angle with respect to the step pulse number is constant, the step pulse can be used as it is as an increment type encoder without adding a special position encoder. There is an advantage of being good.

As described above, when the zooming operation is performed while keeping the focus by using the stepping motor, the locus information of FIG. 6 may be in some form (a trace itself or a function with the lens position as a variable). However, it may be stored in a storage medium provided in the lens control microcomputer or the like.

Then, it is necessary to read the stored locus information according to the position or the moving speed of the variable power lens, and to move the focus lens based on the read locus information.

FIG. 7 illustrates an example of the trajectory following method.
This is a drawing. In FIG. 7, Z _0,Z_1,Z_{2, ...}Z₆
Indicates the zoom lens position, and a_0,a_1,a_{2, ...}a₆
And b_0,b_1,b_{2, ...}b₆For lens control
This is the representative locus stored in the microcomputer.

Further, P _0, P _1, P _{2, ...} P ₆ are loci calculated based on the above two loci. The formula for calculating this locus is described below. P (n + 1) = | P (n) -a (n) | / | b (n) -a (n) | * | b (n + 1) -a (n + 1) | + a (n + 1). ． (1)

According to the above equation (1), for example, in FIG.
And the focus lens is P₀, Then P₀Is the line segment b
₀-A₀The ratio that internally divides the₁
-A ₁The point that internally divides₁I am trying. This P₁-P₀
Position difference and the zoom lens is Z ₀-Z₁To move up to
From the time required, focus lens to maintain focus
Know the speed of movement.

Next, a case will be described in which the stop position of the variable power lens is not limited to only the boundary where the stored representative trajectory data is owned. FIG. 8 is a diagram for explaining the interpolation method in the position of the variable power lens, in which a part of FIG. 7 is extracted to make the variable power lens optional.

In FIG. 8, the vertical axis and the horizontal axis respectively indicate the focus lens position and the variable power lens position, and the representative locus position (the focus lens position relative to the variable power lens position) stored in the lens control microcomputer is zoom lens position _{Z 0, Z 1, ... Z} k-1, Z k. .. Z n a focus lens position at that time by the object _{distance, a 0, a 1, ...} a k-1, a _{k ...} a _n b _0, b _{1, ...} b _k-1, b _{k ...} b _n .

Now, if the zoom lens position is at Z _x not on the zoom boundary and the focus lens position is P _x ,
When a _{x and} b _x are calculated, a _x = a _k- (Z _k -Z _x ) * ( _ak -a _k-1 ) / (Z _k -Z _k-1 ). ． (2) b _x = b _k- (Z _k -Z _x ) * (b _k -b _k-1 ) / (Z _k -Z _k-1 ). ． (3)

That is, the current zoom lens position and two zoom boundary positions sandwiching the zoom lens position, for example, (Z _k and Z in FIG. 8).
_According to the internal division ratio obtained from ( _K-1 ) and the stored representative locus data (a _k, a _k-1, b _k, b _{k-1 in} FIG. 8) of the same object distance, It is possible to obtain a _x, b _x by internally dividing the thing with the above internal division ratio.

Then, according to the internal division ratio obtained from a _x, P _x, b _{x ,} four stored representative data (in FIG. 8, a _k,
a _k-1, b _k, b _k-1 ) with the same focal length (1)
By internally dividing by the internal division ratio as shown in the formula, p _{k and} p _k-1 can be obtained. Then, when zooming from wide to tele, in order to keep the focus from the position difference between the follow-up focus position P _k and the current focus position P _x, and the time required for the zoom lens to move from Z _{X to} Z _K. You can see the moving speed of the focus lens.

When zooming from tele to wide, the position difference between the follow-up focus position P _K-1 and the current focus position P _x, and the time required for the zoom lens to move from Z _{X to} Z _K-1. From this, the moving speed of the focus lens for keeping the focus can be known.

When the variable power lens moves from the telephoto to the wide direction, as is clear from FIG. 6, since the scattered loci converge, the focus can be maintained even by the above-mentioned trajectory following method.

However, in the wide-to-tele direction,
Since it is not known which trajectory the focus lens at the convergent point should follow, the similar trajectory following method cannot maintain the focus.

In order to solve such an inconvenience, there is a method of zooming while selecting a focus cam locus by using front focus and rear focus information by an automatic focus adjustment function (AF). When is off, the manual zoom method described below is performed.

FIGS. 9, 10, 11 and 12 are flowcharts for explaining such a manual zoom control method, and cam locus information stored inside a control microcomputer for executing lens control ( 7 shows a data table of (information shown in FIG. 6).

FIG. 12 is table data of the stored cam locus information, which is the focus focus lens position data A that changes depending on the zoom lens position for each subject distance.
(N, v), the subject distance changes in the column direction of the variable n, and the zoom lens position (focal length) changes in the row direction of the variable v.

In this example, n = 0 represents a subject distance at infinity, and as n increases, the subject distance changes to the closest distance, and n = m represents a subject distance of 1 cm. On the other hand, v = 0 represents the wide end, the focal length increases as v increases, and v = s represents the zoom lens position at the tele end. Therefore, one cam locus is drawn with one row of table data.

Next, the lens control during the manual zoom will be described with reference to the flowcharts of FIGS. It is assumed that the processing shown in FIG. 9 is a subroutine, and AF control and the like are performed separately from this processing.

In FIG. 9, step P601 indicates the start of processing. Step P602 is a processing routine for identifying the shooting distance of the subject being shot from the current zoom lens and focus lens positions, and storing the subject distance information as three locus parameters α, β, γ in a memory area such as a RAM. And is composed of the processing shown in FIG.

In FIG. 10, a step P701 is a process for calculating in which figure area v the current zoom lens position Zx is equally divided by s from the wide end to the tele end on the table of FIG. is there. The calculation method is
This will be described with reference to the flowchart of FIG.

In FIG. 11, in step P801, the zoom area variable v is cleared. Next, step P80.
In 2, the zoom lens position Z (v) on the boundary of the area v is calculated according to the following equation (4).

This Z (v) corresponds to the zoom lens positions Z _0, Z _1, Z _{2 ...} Shown in FIG. Z (v) = (zoom position at tele end−zoom position at wide end) * v / s + wide end zoom position. ． ． ． ． ． (4)

At the next step P803, step P8
It is determined whether Z (v) obtained in 02 is equal to the current zoom lens position Zx. Then, if they are equal, it is determined that the zoom lens position Zx is on the boundary of the zone v, the process proceeds to step P807, and the boundary flag = 1.

If false in step P803, the flow advances to step P804 to determine whether Zx <Z (v). If the determination in step P804 is true, Zx
Is between Z (v-1) and Z (v), at this time, the routine proceeds to step P806 and the boundary flag =
Set to 0. On the other hand, if the determination in step P804 is false,
The process advances to step P805, the zoom zone is incremented, and the process returns to step P802.

As described above, when exiting FIG. 11, the current zoom lens position Zx exists in the v = k-th zoom area on the table of FIG. 12, and whether it exists on the boundary or not. You will be able to know.

Hereinafter, the description will return to the flowchart of FIG. Since the zoom area has been determined in step P701,
In the following process, the position of the focus position on the table of FIG. 12 is calculated.

That is, first, in step P702, the object distance variable n is cleared, and then in step P703, it is determined whether or not the current zoom lens position exists on the boundary of the zoom area. If the boundary flag = 0, it is determined that the object is not on the boundary and the process proceeds to step P705. First, in step P705, Z _k ← Z
(V), Z _k-1 ← Z (v-1).

Next, in step P706, four table data A (n, v-1), A (n, v), A (n + 1,
v-1), A (n + 1, v) are read out, and step P7
In step 07, a _{x and} b _x are calculated from the equations (2) and (3) described above.

On the other hand, if it is determined to be true in step P703, the flow advances to step P704 to call the focus distances A (n, v) and A (n + 1, v) of the subject distance n and the zoom lens position v. , memory as a _x, b _x, respectively.

Next, in Step P708, it is determined whether or not the current focus position P _x is at least a _x . If the determination in step P708 is true, the process proceeds to step P709 to determine whether P _x is b _x or more.

If the determination in step P709 is false, P _x
Is between the subject distances n and n + 1, the trajectory parameters at this time are stored in the memory in step P713 to step P715. In this case, first, in step P713, α = P _x -a and _{x, β} = b _x -a _x in step P714, gamma in step P715
= N.

By the way, what becomes false in step P708 is when the focus position P _x is infinite. At this time, α = 0 in step P712 and step P71
The process proceeds from step 4 to store infinite trajectory parameters.

If the result of step P709 is true, it means that P _x is on the closer side, and step P7
In step 10, the subject distance n is incremented, and in step P711, it is determined whether n is the closest subject distance m or less. If true, the process returns to step P703.

If the result of step P711 is false, it means that P _x is extremely close to the point. At this time, the process from step P712 is proceeded to and the locus parameter of the shortest distance is stored in the memory.

Below, the description returns to the flowchart of FIG. By the step P602, it is possible to store the locus parameter as to which position on the cam locus in FIG. 6 the current zoom and focus lens positions are.

Next, in step P603, it is determined whether or not zooming is in progress. If zooming is in progress, the process proceeds from step P608. If it is determined in step P603 that zooming is not in progress, then the flow proceeds to step P604, where it is determined whether or not an AF operation is in progress. If AF operation is in progress, this processing ends.

If it is determined to be false in step P604, the process proceeds to step P605, and it is determined whether the current manual state has changed to the manual mode or has been in the manual state before.

If the mode is switched to manual, the process proceeds to step P607. If the mode is not switched, the process proceeds to step P606. Step P606
Then, it is determined whether it is in the power focus state. If it is in the non-power focus state, the process proceeds to step P619 to end the process.

On the other hand, if power focusing is in progress, the process proceeds to step P607, and the current locus parameters α, β, γ are set as the manual zoom locus parameters α _m , β _m , γ _m , respectively, as subject distance information to be traced during the manual zoom. Store.

If it is determined in step P603 that zooming is in progress, the processing from step P608 is performed. In step P608, it is determined whether or not the AF operation is in progress. If the AF operation is in progress, the cam locus is changed so as to keep the focus while tracing the cam locus of the distance currently photographed at the time of zooming. Since it is sufficient to control the lens in this way, the process proceeds to step P609. In Step P609, the trajectory parameter obtained in Step P602 is substituted into α _z , β _z , and γ _z as the object distance information for zooming.

Further, if it is during the manual operation at step P608, the routine proceeds to step P610, where α _m , is set to follow the cam locus of step P607 stored in the manual mode.
β _m and γ _m are the trajectory parameters for zoom α _z and β, respectively.
_The process of substituting for _z and γ _z is performed.

Next, in Step P611, it is determined whether the zoom direction is from wide to tele or from tele to wide. If it is wide-to-tele, the process proceeds to step P612, and in the above-described processing of FIG. 11, it is determined whether or not the zoom lens position is on the boundary of the areas. If the boundary flag = 1, the process proceeds to step P613, and if the boundary flag = 0, the process proceeds to step P613.
Proceed to 614.

If it is determined in step P611 that the zoom is tele-> wide, the process proceeds to step P615. The processes of steps P613, P614, and P615 are processes of calculating the difference amount ΔF between the current position Px of the focus lens and the follow-up target position on the zoom boundary adjacent in the zoom direction to be driven. Of | P (n)-
The target position is calculated by replacing a (n) | / | b (n) -a (n) | = [alpha] _z / [beta] _z and fixing the internal division ratio.

At step P613, since the zoom lens position is on the boundary of the zoom area v and the zoom lens moves in the tele direction,
From the representative trajectory data stored in FIG. 12, one tele side data A (γ _z , v + 1) and A (γ _z +1, v + 1) are called, and the following target position is {A ( γ _z +1, V + 1) -A (γ _z , v + 1)} * α
It can be expressed as _z / β _z + A (γ _z , v + 1).

Therefore, the difference between the follow-up target position and the current focus position is ΔF = [{A (γ _z +1, v + 1) -A (γ _z , v +
1)} * α _z / β _z + A (γ _z , v + 1)] − P _x .

On the other hand, in step P614, since it is not on the boundary of the zoom area, A (γ
_z , v) and A (γ _z + 1, v), step P61
In the case of No. 5, since it moves in the wide direction, A (γ
_The above equation is calculated using _z , v−1) and A (γ _z +1, v−1).

Then, in step P616, the focus following speed Fsp is calculated. Fsp is the focus position difference ΔF
Is divided by the zoom lens movement time required to move this distance.

Then, in step P617, the focus lens is driven, and then in step P618, the zoom lens is driven. Then, after that, the flow advances to Step P619 to end the present processing.

As described above, the locus information stored for the manual zoom is used until the power focus is made.
Since it is not updated, it becomes possible to accurately trace the stored specific trajectory no matter how many times the zoom operation is performed.

[0063]

By the way, the trajectory information traced during zooming must be updated as necessary, and is therefore stored in a volatile memory such as a RAM in the lens control microcomputer. Therefore, conventionally, when the power is cut off, there is a problem that the locus information stored before being cut off is erased.

Therefore, after the power is turned on again, α, β, γ
Since == 0, a large blur will occur if the manual zoom is performed with AF off from the wide side. Also, A
When the power is turned off with F off and then turned on again, AF
You may get up when you are off.

Particularly, in the case of a camera having a function of holding the angle of view, the focus position, the electronic zoom magnification, etc. in the state previously set by the photographer, the locus information as described above is held. Otherwise, there is a problem that the camera specifications are inconsistent, and there is a drawback in that the photographer is confused about how to use the camera.

In view of the above problems, the present invention makes it possible to accurately trace a specific trajectory set by the photographer before the power is turned off when the power is turned on again after the power is turned off. The purpose is to

[0067]

An image pickup lens control apparatus according to the present invention includes a second lens group for correcting a movement of a focal plane when the first lens group for performing a magnification change operation moves. In the imaging lens control device for controlling the movement, the second
And a lens driving means for moving the lens group in a direction parallel to the optical axis independently of the first lens group, and when the main power source is cut off, the first lens group is moved when the main power source is cut off. 1
Storage unit for storing and holding the cam locus information of the second lens group for correcting the movement of the focal plane due to the movement of the second lens group, and turning on the power again after the main power supply is cut off. When a zooming operation is performed later by moving the first lens group, the information reading means for reading the cam locus information held in the storage means and the main power supply are cut off. After the power is turned on again, a predetermined calculation is performed based on the cam locus information read by the information reading means to correct the movement of the focal plane due to the movement of the first lens group. And a correction position calculation means for obtaining the position of the second lens group and outputting it to the lens driving means.

Another feature of the imaging lens control device of the present invention is that the storage medium used in the storage means is a volatile memory backed up by a power supply provided separately from the main power supply, or It is characterized by being one of the non-volatile memories.

Another feature of the image pickup lens control device of the present invention is that the above-mentioned storage is used as a storage medium for storing and holding the above-mentioned cam locus information when the main power source is cut off. The means is provided with both a non-volatile memory and a volatile memory, and when the main power source is turned on, the cam locus information stored in the non-volatile memory is loaded into the volatile memory. In addition, the cam locus information stored in the volatile memory is loaded into the non-volatile memory when the main power supply is cut off.

Another feature of the image pickup lens control device of the present invention is that the cam locus information held by the storage means corresponds to the first lens group position previously stored in the storage medium. It is characterized in that it is information specified by the discrete focus position information of the second lens group and the positions of the first and second lens groups at the time of photographing.

[0071]

Since the present invention has the above-mentioned technical means, even when the main power supply is cut off, the cam locus information photographed before the main power supply is cut off is retained without being erased, and the main power supply When the camera is reclosed, the held cam locus information is read out, and the movement of the focal plane caused by the movement of the first lens group is corrected based on the read out cam locus information. Since the second lens group is moved to, the trace set by the photographer before the main power is cut off can be accurately traced even when the magnification change operation is performed after the power is turned on again. Like

According to another feature of the present invention, the storage means is provided with both a non-volatile memory and a volatile memory, which are stored in the non-volatile memory when the main power is turned on. The cam locus information is loaded into the volatile memory, and the cam locus information stored in the volatile memory is loaded into the non-volatile memory when the main power supply is cut off. In general, the contents are deleted /
It is possible to minimize the number of times of rewriting of the nonvolatile memory, which has a limited number of times of rewriting.

[0073]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an image pickup lens control device of the present invention will be described below with reference to the drawings. FIG. 1 is a functional configuration diagram for explaining an outline of an imaging lens control device of the present invention.

As shown in FIG. 1, this image pickup lens control device is provided with a lens driving means 3, a distance information storage means 4, a distance information reading means 5 and a corrected position calculating means 6, and outputs the light S1 from the subject. The first lens group 1 for zooming and the second lens group 2 for correcting the movement of the focal plane when the first lens group 1 moves are independently provided in a direction parallel to the optical axis. I am trying to move it to.

The lens driving means 3 is provided to independently move the first lens group 1 and the second lens group 2 in the direction parallel to the optical axis, and calculates the correction position. Corrected position information S output from the means 6
The second lens group 2 is moved based on 3.

The distance information storage means 4 stores and holds the distance information S2 of the object photographed before the main power supply is cut off when the main power supply of the image pickup apparatus is cut off. It is a thing. Further, the distance information reading means 5 is
This is for reading out the distance information of the subject held in the distance information storage means 4 when the first lens group is moved when the main power source is turned off and then turned on again.

The correction position calculating means 6 is for calculating the correction position information S3 to be output to the lens driving means 3 as described above. The corrected position calculating means 6 receives the distance information S of the subject inputted from the distance information reading means 5.
The correction position information S3 is calculated by performing a predetermined calculation based on 2.

In this embodiment, since the position of the second lens group 2 is corrected as described above, even if the main power supply is cut off, it is set by the photographer before the main power supply is cut off. The trajectory can be traced accurately, and blurring can be prevented when the main power is turned on again.

Next, a more specific configuration of the image pickup lens control device of the present invention will be described in detail according to the first and second embodiments. FIG. 2 is a configuration diagram of an image pickup lens control device showing a first embodiment of the image pickup lens control device of the present invention.

In FIG. 2, 101, 102, 103, 1
Reference numerals 04 and 105 are elements constituting an inner focus type lens system, and each includes a fixed front end lens group, a second lens group for performing zooming, an aperture,
It is a fixed third lens group, and a fourth lens group having both a competition function and a focusing function.

The image light transmitted through this lens system is
An image is formed on the image pickup surface of the image pickup device (CCD) 106 and converted into a video signal by photoelectric conversion. 107 is the image sensor 1
An automatic gain control circuit (AGC) that electrically amplifies the video signal photoelectrically converted in 06.

A camera signal processing circuit 108 generates a TV signal by adding a synchronizing signal after performing processing such as gamma correction, color separation, and color difference matrix, 109 is an LCD display circuit, and 110 is a liquid crystal display device (LCD). , 111 are video tape recorders.

Further, the automatic gain control circuit 10
The video signal amplified in 7 is applied to the exposure control circuit 112, the AF
It is sent to the evaluation value processing circuit 114. Exposure control circuit 112
Then, a predetermined area of the video signal is gated in accordance with the photometry gate signal from the frame generation circuit 113, and the IG driver 116 and the IG meter 117 are driven so as to keep the input level of the video signal in the gated area constant. Then, the diaphragm 103 is controlled to adjust the light amount.

Further, in the AF evaluation value processing circuit 114, only the high frequency component of the video signal in the distance measuring frame is extracted and processed according to the distance measuring gate signal from the frame generating circuit 113. Reference numeral 115 denotes a lens control microcomputer, which performs lens drive control and frame control for changing the distance measurement / photometry area according to the AF evaluation signal strength.

The lens control microcomputer 115 communicates with a system control microcomputer (hereinafter referred to as "syscon") 130, and obtains information such as on / off of power supplied to this system. The system controller 130 reads the state of the power SW unit 131 operated by the photographer, operates the main SW 132 according to the state, and supplies the main power 133 to the system 134 (the portion surrounded by the broken line). Control of.

Reference numerals 118 and 120 denote drivers for outputting drive energy to a lens drive motor in accordance with drive commands for the second lens group 102 and the focus lens 105 output from the lens control microcomputer 115, respectively.

Reference numerals 119 and 121 denote motors for driving the second lens group 102 and the focus lens 105. A method of driving the motor when the lens driving motor is a stepping motor will be described below.

The lens control microcomputer 115 determines the drive speeds of the zoom motor and the focus motor by program processing, and uses them as the rotation frequency signals of the stepping motors to drive the driver 118 of the zoom motor 119 and the drive driver 120 of the focus motor 121. Send to.

Further, the drive / stop commands for the motors 119 and 121 and the rotation direction command for each motor are given to each driver 11.
I am sending it to 8, 120. The drive / stop signal and the rotation direction signal mainly depend on the states of the zoom switches 124 and 125 for the zoom motor, and the AF / MF switching SW 128 for the focus motor.
Is in the AF state and during zooming, it responds to a drive command determined by processing in the lens control microcomputer 115.

When the AF / MF switching SW 128 is in the manual focus state, the power focus SW 126,
And 127. The resistor 123 shown in FIG. 2 is a pull-up resistor group.

The motor drivers 118 and 120 set the phases of the four motor excitation phases to the forward rotation and reverse rotation phases according to the rotation direction signal, and to generate four motor excitation phases according to the received rotation frequency signal. By outputting while changing the applied voltage (or current) of the phase, the output to the motor is turned on / off according to the drive / stop command while controlling the rotation direction and rotation frequency of the motor. .

Inside the lens control microcomputer 115, FIG.
The ROM area where the processing of the contents of FIG.
There is a RAM area that is a volatile memory that stores the parameters used in the process. In this RAM area, α, β, γ, α _m , β _m , of the cam locus information described in [Prior Art],
γ _m , α _z , β _z , γ _z, etc. are stored.

Therefore, in order to solve the problems described in the section of [Problems to be solved by the invention], even when the main power supply 133 is cut off, the locus information α _m at the time of manual operation,
A means to hold β _m and γ _m so that they do not disappear is necessary.

Therefore, in this embodiment, the volatile memory 115a for storing the locus of the lens control microcomputer 115 is provided with a backup power source 129 such as a lithium battery different from the main power source 133, and the volatile memory 115a is backed up. The locus information α _m , β _m , and γ _m for manual storage stored here is made non-volatile.

By doing so, in the case of the image pickup lens control device of this embodiment, since the trajectory information at the time of manual operation is remembered regardless of whether the main power source operated by the photographer is on or off, the main power source is remembered. Even if the manual zoom is performed after the power is turned on again, the trajectory set before the power is shut off can be accurately traced, so that blurring can be prevented when the main power is turned on again.

Next, the second embodiment of the image pickup lens control device of the present invention.
An example will be described. In the above-described first embodiment, a method of backing up the contents of the volatile memory in the control microcomputer with a power source 129 such as a battery other than the main power source and making the contents non-volatile has been described.

However, if the battery life is exhausted by the above-mentioned method, blurring will occur in the manual zoom after the power is turned on again. In order to prevent such an inconvenience, in the second embodiment, the trajectory information is stored by using a nonvolatile memory (electrically erasable ROM: EEPROM) in the lens control microcomputer 115. .

FIG. 3 shows a block diagram of the second embodiment. Note that, in FIG. 3, parts having the same contents as in FIG. 2 are denoted by the same reference numerals, and description thereof will be omitted. The imaging lens control device of FIG. 3 has the above-mentioned EEPROM 1001a in the lens control microcomputer 1001 and stores the trajectory information α _m , β _m , γ _m at the time of manual operation.

Therefore, in the case of this embodiment, the locus information can be held without the backup power source 129 shown in FIG. However, the EEPROM 100
1a generally has a limited number of times of erasing / rewriting the contents, so in this embodiment, the RAM 1001b and the EEPROM 1001 are based on the control flow shown in FIG.
Data is exchanged with a so as to minimize the number of rewrites.

The process shown in the flowchart of FIG. 4 is a process performed by the lens control microcomputer 115, and the lens control microcomputer 115 executes this process while mutually communicating with the system controller 130.

In FIG. 4, step P1101 indicates the start of processing. The next step P1102 is a process of determining whether or not the voltage is supplied from the main power supply 133. For example, when the power supply 133 such as a battery is attached to the camera, the syscon 130 operates.

When the photographer turns on the power SW unit 131, the syscon 130 controls the main SW 132 to supply an operating voltage to the entire system 134.
Main power-on information is sent to the lens control microcomputer 115.

The lens control microcomputer 115 performs the determination process of step P1102 based on the information, waits on the spot until the main power source is turned on, and when it is turned on, the process proceeds to step P1103 to store it in the EEPROM. Reads out certain cam locus information and stores the data in RAM 1001b.
It is stored in the trajectory memory α _m , β _m , γ _m for the manual in the above.

Next, in step P1104, the lens control processing routine as shown in the flowchart of FIG. 9 in the [Prior art] section is executed, and then in step P1105, the photographer operates the power supply SW unit 131. Then, it is determined whether the power is turned off. The above determination is performed by obtaining information from the syscon 130. Then, when the power SW unit 131 is operated and powered off, the process proceeds to step P1106.

In Step P1106, Step P110
Contrary to the processing of 3, the information of the manual locus memory in the RAM is read, the read data is written to the assigned address for locus information storage in the EEPROM, and the locus information is stored. Step P1107 is Syscon 1
When the switch 30 turns off the SW 132 and the supply of the voltage to all the systems 134 is cut off, if it is in the voltage supply state, it waits as it is, and when it is cut off, returns to Step P1102.

The case where the EEPROM is built in the control microcomputer has been described above. However, even when the EEPROM is not built in, the same control as that shown in FIG. 4 is executed while controlling the communication of the external EEPROM. As a result, the same effect as in the case of being built in is obtained.

[0107]

As described above, according to the present invention, when the main power source is cut off, the cam locus information photographed before the main power source is cut off is stored in the storage means. When the main power is turned on again, the stored and held cam locus information is read out, and the movement of the focal plane caused by the movement of the first lens group is read out. Since the second lens group is moved so as to be corrected based on the locus information, even when the magnification change operation is performed after the power is turned on again, it is set by the photographer before the main power is cut off. You will be able to trace the trajectory accurately. As a result, it is possible to prevent blurring even when the scaling operation is performed after the power is turned on again.

According to another feature of the present invention, the storage means is provided with both a non-volatile memory and a volatile memory, which are stored in the non-volatile memory when the main power is turned on. The cam locus information is loaded into the volatile memory, and the cam locus information stored in the volatile memory is loaded into the non-volatile memory when the main power supply is cut off. In general, the contents are deleted /
The number of rewrites of the nonvolatile memory, which has a limited number of rewrites, can be minimized, and the life of the nonvolatile memory can be extended.

[Brief description of drawings]

FIG. 1 is a functional configuration diagram showing a schematic configuration of the present invention.

FIG. 2 is a configuration diagram of an image pickup lens control device according to a first embodiment.

FIG. 3 is a diagram of an imaging lens control device showing a second embodiment.

FIG. 4 is a flowchart showing an example of processing performed by a lens control microcomputer.

FIG. 5 is a diagram illustrating a configuration of an inner focus type lens system.

FIG. 6 is a characteristic diagram showing an example in which the positions of focus lenses are continuously plotted.

FIG. 7 is a diagram for explaining an example of a trajectory following method conventionally devised.

FIG. 8 is a diagram for explaining an interpolation method in a variable power lens position direction.

FIG. 9 is a flowchart for explaining lens control during manual zoom.

FIG. 10 is a flowchart for explaining lens control during manual zoom.

FIG. 11 is a flowchart for explaining lens control during manual zoom.

FIG. 12 is a diagram showing an example of table data of cam locus information.

[Explanation of symbols]

1 First lens group 2 Second lens group 3 Lens drive means 4 Distance information storage means 5 Distance information reading means 6 Correction position calculation means S1 light from the subject S2 Subject distance information

Claims (4)

(57) [Claims] 1. An imaging lens controller for controlling the movement of a second lens group for correcting the movement of a focal plane when the first lens group for performing a magnification change operation moves, wherein: And a lens driving means for moving the lens group of (1) in a direction parallel to the optical axis independently of the first lens group, and the first lens group when the main power source is cut off when the main power source is cut off. Storage means for storing and holding the cam locus information of the second lens group for correcting the movement of the focal plane due to the movement of the first lens group; When the zooming operation performed by moving the first lens group after the closing is performed, the information reading means for reading the cam locus information held in the storage means and the main power supply are shut off. After turning on the power again, the above information reading means By performing a predetermined calculation based on the read cam locus information, the position of the second lens group is obtained so as to correct the movement of the focal plane accompanying the movement of the first lens group, and the lens is obtained. An image pickup lens control device, comprising: a correction position calculation means for outputting to a driving means. 2. The storage medium used in the storage means is one of a volatile memory and a non-volatile memory backed up by a power supply provided separately from the main power supply. 1. The imaging lens control device according to 1. 3. The storage means is provided with both a non-volatile memory and a volatile memory as a storage medium for storing and holding the cam locus information when the main power supply is cut off. When the main power is turned on, the cam locus information stored in the non-volatile memory is loaded into the volatile memory, and when the main power is shut off, the volatile memory is stored in the volatile memory. The stored cam locus information is loaded into the non-volatile memory.
The imaging lens control device according to. 4. The cam locus information held by the storage means is discrete focus position information of the second lens group with respect to the position of the first lens group, which is stored in advance in a storage medium, and shooting information. The imaging lens control device according to claim 1, wherein the information is information specified by the first and second lens group positions at the time.