JP3224556B2 - Lens position control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens position control device for an image pickup optical system in a silver halide photographic camera, a still video camera, a video camera and the like.

[0002]

2. Description of the Related Art Hitherto, there have been various types of lens position detecting means of a lens position control device, such as an optical type and an electric type.
The optical type includes a photo interrupter, a photo coupler, and the like. In the electric type, potentiometer, electric capacity type,
There are gray scales and the like.

[0003]

In the conventional lens position detecting means, environmental conditions such as shape, temperature, humidity, etc.
Its characteristics change depending on the manufacturing state and the like.

[0004] In the case of a photo interrupter or a gray scale, characteristics change due to a change in shape. In electrical capacity <br/> weight form, the dielectric constant between the electrodes is changed by temperature and humidity, also the shape and the electrode spacing of the electrodes is different for characteristic changes due to production conditions. Further, the potentiometer and the photocoupler also change due to the environment, and the characteristic of the output change depending on the position also changes according to the manufacturing state.

On the other hand, in recent years, imaging optical systems have tended to be miniaturized, and high precision is required for lens position control.

However, when the conventional lens position detecting means is used for lens position control, the characteristics of the position detecting means change due to the above-mentioned reasons, so that there is a disadvantage that the stopping accuracy of the lens cannot be increased. .

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a lens position control device for further improving lens position detection .

[0008]

According to a first aspect of the present invention, there is provided a variator lens which moves in the optical axis direction to perform zooming.
Focus lens that moves in the optical axis direction for focusing
With the variator lens changing its magnification.
An optical system that changes the position sensitivity of the focus lens is provided.
In the obtained lens position control device, a moving means for moving the variator lens and the focus lens by electromechanical conversion, a position detecting means for detecting the position of the variator lens and the focus lens , Output and the variator lens and focus lens
Storage means for storing correction data for correcting an error between each position and a design value; and the variator element based on an output of the position detection means and the correction data stored in the storage means.
Computing means for computing each position of the zoom lens and the focus lens, and the correction data is stored in the variator lens and the focus lens.
Each lens position at multiple points within the movement range of the cas lens
A correction data, said that the correction data is obtained
Each lens position is the position sensitivity of the focus lens
Is set at a position where the position sensitivity is large according to The second aspect of the present invention provides the optical axis
Variator lens that moves in the direction to change the magnification and the optical axis direction
And a focusing lens that moves to
However, as the variator lens moves, the entire system focuses.
In a lens position control device provided with an optical system in which the width of a point depth changes, the variator
'S, a moving means for moving the focusing lens, said bar
Position detecting means for detecting the positions of the variator lens and the focus lens ; and an output from the position detecting means and the burr
A storage unit for storing correction data for correcting an error between a design value of each position of the eta lens and the focus lens, and the variator lens and the focus lens based on an output of the position detection unit and the correction data stored in the storage unit
Calculating means for calculating the respective positions of the variator lens and the focus lens.
Correction data for each lens position at multiple points within
Each lens position for which the correction data is required is
The optical system changes with a variable power movement of a variator lens.
Of the depth of focus according to the depth of focus of the entire system
It is characterized in that many settings are made wherever possible.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Before describing the embodiments of the present invention, the following description will be made based on an example in which the technology underlying the present invention is applied to a video camera.

(First Base Technology) FIGS. 1 to 5 show a first base technology. In FIG. 1, 1
Reference numeral denotes a variator that moves in the optical axis direction to perform a magnification change operation. A signal is sent to the zoom motor driver 3 when the zoom switch 2 is pressed, and the zoom motor 4 is driven to move in the optical axis direction. Reference numeral 5 denotes an automatic focusing device, which is a CCD
And the like, and detects the value of the high-frequency component of the signal from the imaging member 6, and outputs a focus signal. The CPU 7 sends a signal to the focus motor driver 9 to move the focus lens 8 so that the focus signal becomes the maximum value, and drives the focus motor 10.

Reference numeral 11 denotes a zoom encoder, which changes a contact point of a contact moving with the variator 1 with an electric resistor to change a resistance value between terminals. A voltage change due to the change in the resistance value is read by a zoom encoder reading circuit 12.
CPU 7 detects the first correction data memory 1
3, the position of the variator 1 is detected. 1
Reference numeral 4 denotes a focus encoder, and a focus lens 8
A first electrode is provided outside the focus lens holding frame that moves together, a second electrode is provided inside the fixed lens barrel, and the facing area between the first electrode and the second electrode changes. The electric capacitance between the first electrode and the second electrode changes. A focus encoder reading circuit 1 for the electric capacity
5 and the CPU corrects the second correction data memory 16
And the position of the focus lens 8 is detected.

FIG. 2 shows the focus encoder 14 of FIG.
It is an enlargement of a part. Reference numeral 101 denotes a lens frame, which is movable in the optical axis direction while holding a lens (not shown) inside, and a first electrode 103 is formed outside the lens frame. Reference numeral 103 denotes a fixed lens barrel, on the inside of which a second electrode 1 is provided.
04 is formed. Figure 3 is a diagram showing a characteristic when actually manufacturing the encoder FIG. Figure 3
The horizontal axis shows the focus lens position, and the vertical axis shows the output level of the position signal. Although the design value or the desired output characteristic is a characteristic as shown by a broken line A, the actual output characteristic varies due to manufacturing errors in the shape of the electrode and the electrode interval.
A solid line B is obtained.

Therefore, in the first base technology, the difference between the broken line A and the solid line B in FIG. 3 is stored in advance in the first correction data memory 13 as correction data, and the output from the focus encoder is used as a design value. By calculating the focus lens position in the CPU 7, an accurate focus lens position can be obtained. When a large amount of correction data cannot be stored because the capacity of the ROM for storing data is small, several reference positions of the focus lens are determined as the contents of the first correction data memory 13,
The difference between the broken line A and the solid line B at the reference position may be stored in the first correction data memory 13, and the CPU 7 may calculate the correction data at a position between the reference positions by interpolation. Further, an arithmetic expression or a constant for calculating the difference between the broken line A and the solid line B may be stored in the correction data memory 16 as correction data, and the CPU 7 may calculate the correction data.

FIG. 4 is an enlarged view of the zoom encoder 11 of FIG. 151 is a resistor, and the contact 15
2 moves in the optical axis direction together with the variator 1 to divide a voltage applied from a DC power supply (not shown) between the terminals 153 and 154 and output the divided voltage to the terminal 155.
FIG. 5 shows characteristics of the resistance value between the terminal 153 and the terminal 155 and the variator position. In FIG. 5, the horizontal axis indicates the variator position, and the vertical axis indicates the resistance value between the terminal 153 and the terminal 155. The design value or the desired output characteristic is a characteristic as indicated by a broken line A ', but the actual resistance value is
Variations occur in the resistivity distribution of the resistor due to manufacturing errors,
It becomes like the solid line B '.

Therefore, in the first base technology , the difference between the dashed line A 'and the solid line B' in FIG. 5 is stored in advance in the first correction data memory 13 as correction data, and the design value is obtained from the output of the zoom encoder. Is calculated by the CPU 7 to obtain an accurate resistance value and an accurate variator position. When a large amount of correction data cannot be stored because the capacity of the ROM for storing data is small, several reference positions of the variator are determined as contents of the first correction data memory 13 and a broken line A 'at the reference position is set. And the solid line B 'may be stored in the first correction data memory 13, and the CPU 7 may calculate the correction data at a position between the reference positions by interpolation. Further, an arithmetic expression or a constant for calculating the difference between the broken line A 'and the solid line B' may be stored in the second correction data memory 16 as correction data, and the CPU 7 may calculate the correction data.

With the above-described configuration, the lens position can be accurately detected, so that highly accurate lens position control can be performed. Note that the focus encoder and the variator encoder may have the opposite configurations.
Further, the present invention is not limited to the focus lens and the variator, and may be used for other movable lenses.

(Second Premise Technique) FIG. 6 shows a second premise technique of the present invention showing a case where a photocoupler is used as a position detecting device. The components denoted by the same reference numerals as those in FIG. 1 indicate the same functions as those in FIG. Reference numeral 201 denotes a position sensing detector (hereinafter referred to as PSD), which detects and outputs the position of the spot light incident on the light receiving surface. Reference numeral 202 denotes a slit that moves together with the movable lens.
03 is incident on a position proportional to the movable lens of the PSD 201. CPU 7 is a motor driver 20
When the signal is output to 5, the motor 206 is driven, and the movable lens 207 moves in the optical axis direction. The PSD output reading circuit 204 converts the signal from the PSD 201 into the movable lens 20.
7 and output to the CPU 7. The CPU 7 compares the data stored in the correction data 208 with the output of the PSD output reading circuit 204 and calculates
7 is detected.

FIG. 7 shows the PSD 201. When the spot light 251 enters the light receiving surface 252, photoelectrons are generated inside the PSD and a photocurrent flows, and the terminal 253 and the terminal 25
Voltage appears at 4. The terminal 255 is connected to a power supply (not shown).

However, when the slit 202 of the PSD 201 and the infrared light emitting diode 203 are actually combined, there is a difference between the position of the movable lens and the output of the PSD 201 due to the positional relationship between them and the variation in the characteristics of the PSD 201. Occurs.

FIG. 8 is a diagram showing characteristics when the position detecting device as shown in FIG. 7 is actually manufactured. FIG.
In the graph, the horizontal axis represents the position of the movable lens, and the vertical axis represents the output level of the position signal. The design value or the desired output characteristic is a characteristic like a broken line A ″, but the actual output characteristic is
When the PSD 201, the slit 202, and the infrared light emitting diode 203 are combined, a difference is generated between the position of the movable lens and the output of the PSD 201 due to a positional relationship between them and a variation in characteristics of the PSD 201, as shown by a solid line B ″. become.

Therefore, in the second premise technique , the difference between the broken line A "and the solid line B" in FIG. 8 is stored in advance in the correction data memory as correction data, and the movable lens at the design value is obtained from the output of the position detecting device. By calculating the position in the CPU 7, an accurate movable lens position can be obtained. When a large amount of correction data cannot be stored because the capacity of the ROM for storing data is small, several reference positions of the movable lens are determined as contents of the correction data memory, and a broken line A ″ and a solid line B at the reference positions are set. Is stored in the correction data memory, and the CPU 7 calculates the correction data at a position between the reference positions by interpolation. Further, the broken line A "and a solid line B" is stored in the correction data memory arithmetic expressions and constants for calculating a difference between the correction data still may calculate the correction data in the CPU 7, the second premise The contents of the correction data memories 13, 16, and 208 that constitute the technology include characteristics variation due to manufacturing conditions in a position detecting unit that detects the position of a movable lens such as a focus lens and a variator.
In addition, any information may be used as long as the information is used to correct the difference between the output of the position detecting means and the position of the movable lens, which is caused by variations in the positions and characteristics of the components constituting the position detecting means.

(Third Premise Technique) FIG. 9 is a block diagram, and the components denoted by the same reference numerals as those in FIG. 1 are the same as the components in FIG. Reference numeral 301 denotes a main switch. When the main switch 301 is closed, a power-on reset circuit 302 operates to perform various initial setting operations. Reference numeral 303 denotes a first group lens, and 304 denotes a second group lens, each of which moves in the opposite direction to the optical axis direction to perform a zooming operation. 305 zoom ene
The encoder is a coder and outputs the detected position of the rear focus zoom lens indicating the third prerequisite technology of the second group lens 304 to the zoom encoder reading circuit 12, and the zoom encoder reading circuit 12 outputs the information to the CPU. 3
Reference numeral 06 denotes a fixed third group lens, and reference numeral 307 denotes a fourth group lens which is a focus lens. Reference numeral 308 denotes a focus encoder, which outputs the detected position of the fourth group lens 307 to the focus encoder reading circuit 13, and the focus encoder reading circuit 13 outputs the information to the CPU 7. The area data memory 309 stores predetermined area division data for the outputs of the zoom encoder output circuit 12 and the focus encoder output circuit 13. Speed data memory 31
0 stores information on the drive speed of the focus lens that is predetermined for the above-mentioned area.
The correction data memory 311 includes the zoom encoder 3
05 and the focus encoder 308 are stored.

When the zoom switch 2 is pressed, the CPU detects the pressed zoom direction and outputs information to the zoom motor drive 3 to drive the zoom motor 4 in that direction to perform zooming. However, in the optical system according to the base technology, when zooming is performed on the same subject,
The, can not be maintained if <br/> focus when not move the variable power in the focusing lens 307. One example is shown in Figure 10 (a). In FIG. 10A, the horizontal axis represents the position of the second lens unit, the vertical axis represents the position of the fourth lens unit, and the curve represents the focus locus of the focus lens 307 at the illustrated object distance. For this reason , during zooming, the variator position and the focus lens position are divided into blocks, and the same focus lens speed is read out within the same block in the block to control the focus lens 307. I have. One example is shown in FIG . During zooming, the focus lens 3 is driven at a focus lens driving speed corresponding to the block.
The CPU outputs a signal to the focus motor drive 9 so as to drive 07. With this configuration, it is possible to maintain focus even during zooming. During zooming, the focus lens position with respect to the variator position stored in advance may be read, or the focus lens may be controlled by a signal output from the automatic focusing device 5, and during zooming, The focus lens position to be moved may be calculated and obtained from the stored focus lens position with respect to the variator position, and any configuration that can maintain focus during zooming may be used. In performing the above-described control, detection of the focus lens position and the variator position is an important factor.

FIG. 2 is an enlarged view of a part of the focus encoder 308. Reference numeral 101 denotes a lens frame, which is movable in the optical axis direction while holding a lens (not shown) inside,
A first electrode 103 is formed outside the first electrode 103. 10
Reference numeral 3 denotes a fixed lens barrel, on which a second electrode 104 is formed. FIG. 3 is a diagram showing characteristics when the encoder as shown in FIG. 2 is actually manufactured. 3, the horizontal axis indicates the focus lens position, and the vertical axis indicates the output level of the position signal. The design value or the desired output characteristic is a characteristic as shown by a broken line A, but the actual output characteristic is varied as shown by a solid line B due to variations in the shape of the electrodes and the electrode spacing due to manufacturing errors.

Therefore, in the third premise technique , the difference between the broken line A and the solid line B in FIG. 3 is stored in advance in the correction data memory 311 as correction data, and the focus lens position at the design value is obtained from the output of the focus encoder. The CPU
By calculating in step 7, an accurate focus lens position can be obtained. When a large amount of correction data cannot be stored because the capacity of the ROM for storing data is small, the contents of the correction data memory 311 are as follows.
Several reference positions of the focus lens are determined, and the difference between the broken line A and the solid line B at the reference position is stored in the correction data memory 311. May be calculated. Further, an arithmetic expression or a constant for calculating the difference between the broken line A and the solid line B may be stored in the correction data memory 311 as correction data, and the CPU 7 may calculate the correction data.

FIG. 4 is an enlarged view of the zoom encoder 305. Reference numeral 151 denotes a resistor. When the contact 152 moves in the optical axis direction together with the variator 1, a voltage applied from a DC power supply (not shown) is divided between the terminals 153 and 154 and output to the terminal 155. I do. FIG.
Indicates the characteristics of the resistance value between the terminals 153 and 155 and the variator position. The horizontal axis indicates the variator position, and the vertical axis indicates the resistance value between the terminal 153 and the terminal 155. The design value or the desired output characteristic is a characteristic as indicated by a broken line A ', but the actual resistance value is varied as shown by a solid line B' due to a variation in the resistivity distribution of the resistor due to a manufacturing error . Therefore, in the third premise technology , the difference between the broken line A 'and the solid line B' in FIG. 5 is stored in advance in the correction data memory 311 as correction data, and the resistance value at the design value is obtained from the output of the zoom encoder. By calculating in the above, an accurate resistance value is obtained and an accurate variator position is obtained. ROM for storing data
When a large amount of correction data cannot be stored due to the small capacity of the variator, several reference positions of the variator are determined as the contents of the correction data memory 311 and the difference between the broken line A 'and the solid line B' at the reference position is determined. The correction data may be stored in the correction data memory 311 and the CPU 7 may calculate the correction data at a position between the reference positions by interpolation. Further, an arithmetic expression or a constant for calculating the difference between the broken line A 'and the solid line B' may be stored in the correction data memory 311 as correction data, and the CPU 7 may calculate the correction data.

(First Embodiment) FIG. 11 shows a first embodiment of the present invention. In the first embodiment of the present invention, the accuracy of lens position detection is improved in accordance with the position sensitivity of the fourth group lens described in each of the above-described base technologies. In the optical system according to the present invention,
The position sensitivity of the fourth lens unit to the focal point shift changes depending on the focal length and the subject distance. This position sensitivity is
For example, it changes as shown in FIG. In FIG. 11, the vertical axis
The position sensitivity of the fourth group lens of
Sensitivity increases, and the lower the vertical axis, the lower the sensitivity
You. For example, if the subject distance is infinite, telephoto from the wide-angle side
As the second lens unit moves to the side, the sensitivity of the fourth lens unit increases.
Sensitivity increases, the second group lens passes the maximum sensitivity
And then proceed to the telephoto side, the position sensitivity of the fourth group lens
Rapidly decreases. When the subject distance is 10 cm,
When the second lens unit moves from the wide-angle side to the telephoto side,
As a result, the position sensitivity of the fourth lens unit increases. In such a case, if the detection accuracy of the fourth group lens position is changed in the same manner as the fourth group lens position sensitivity in accordance with the second group lens position, the position of the fourth group lens position sensitivity where the fourth group lens position sensitivity is large is reduced. Since the focus movement due to the movement of the fourth group lens is large, the focus movement can be suppressed small by detecting the position of the fourth group lens with high accuracy in the case where the sensitivity of the fourth group lens is high, and the focus detection by the automatic focusing device. In this case, it is possible to reduce the focal point shift at the time of zooming, and to suppress the focal point shift accompanying zooming. As a method for performing high-precision correction, when several reference positions of the variator are determined as contents of the correction data memory 311, the number of the reference positions is increased where the fourth-group lens position sensitivity is high, and the correction data is corrected. Stored in the memory 311
The CPU 7 may calculate the correction data at a position between the reference positions by interpolation. When an arithmetic expression or a constant for calculating the difference is stored as correction data in the correction data memory 311, when the correction data is calculated in the CPU 7, the correction is performed with high accuracy where the fourth-group lens position sensitivity is large. What is necessary is just to store an arithmetic expression or a constant that can be stored in the correction data memory 311.

(Second Embodiment) In the second embodiment, the accuracy of detecting the position of the fourth lens unit is increased in accordance with the depth of focus. In general
The depth of focus is narrow on the wide-angle side and narrow on the telephoto side.
When the aperture is narrowed down, the width is wide, and when the aperture is opened, the width is narrow. Depth of focus width
In a narrow place, when the moving distance of the fourth group lens from the in-focus position is the same, the size of the circle of confusion is larger than in a place where the depth of focus is wide, and the focal movement by the movement of the fourth group lens is large. Therefore, by detecting the position of the fourth lens group in a narrow range of the depth of focus with high accuracy, the focus movement can be suppressed to be small, and the focus movement at the time of focus detection by the automatic focusing device can be reduced. There is an effect that the focal point shift accompanying zooming can be kept small.
As a method for performing highly accurate correction, a correction data memory 31 is used.
When several reference positions of the variator are determined as the contents of 1, when the depth of focus is narrow , the number of the reference positions is increased and stored in the correction data memory 311;
The CPU 7 may calculate the correction data at a position between the reference positions by interpolation. Further, when an arithmetic expression or a constant for calculating the difference is stored in the correction data memory 311 as the correction data, the CPU 7 can calculate the correction data with high accuracy when the correction data is calculated, where the depth of focus is narrow. An arithmetic expression or a constant may be stored in the correction data memory 311. During zooming, the variator position and the focus lens position are divided into blocks, and the same focus lens speed is read out within the same block in the block, and the focus lens 30 is read.
In the case where control 7 is performed, the block may be divided as shown in FIG. 12 or another block may be divided.

The optical system constituting the present invention is not limited to the rear focus zoom, but may be any optical system in which the position sensitivity of the focus lens changes with zooming. The present invention can also be applied to a so-called front lens focus optical system in which the closest lens group is moved to perform a focusing operation . Further, the lens group for performing the correction is not limited to the focus lens and may be any lens group that moves.

[0030]

As described above, the invention according to claim 1 is described.
According to the figure, the zoom lens moves
In an optical system in which the position sensitivity of
The correction data for correcting the error between the output from the position detecting means of the variator lens and the focus lens and the design value of each lens position is obtained by moving the variator lens and the focus lens.
The correction data for each lens position at multiple points within the range.
The respective lens positions for which the correction data is required are
The position sensitivity depends on the position sensitivity of the focus lens.
Since many settings are made at a place where the sensitivity is high, it is possible to perform highly accurate correction without storing a large number of correction data. According to the invention according to claim 2, in an optical system in which the position sensitivity of the focus lens changes as the variator lens changes magnification, the output from the variator lens and the focus lens position detection means and the design value of each position The correction data for correcting the error with the variator lens is the correction data of each lens position of a plurality of points within the moving range of the focus lens, and the respective lens positions for which the correction data is obtained are used for zooming movement of the variator lens. Since the width of the depth of focus is set to be small in accordance with the width of the depth of focus of the entire optical system that changes with the change, high-precision correction can be performed without storing a large number of correction data. Becomes possible.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a first base technology of the present invention.

FIG. 2 is a perspective view of a position detection device using electric capacitance.

FIG. 3 is a diagram showing characteristics of a position detection device using electric capacitance.

FIG. 4 is a perspective view of a position detection device using a potentiometer.

FIG. 5 is a diagram showing characteristics of a position detection device using a potentiometer.

FIG. 6 is a block diagram showing a configuration of a second base technology of the present invention.

FIG. 7 is a perspective view of a position detection device using a photocoupler.

FIG. 8 is a diagram showing characteristics of a position detection device using a photocoupler.

FIG. 9 is a block diagram showing a third base technology of the present invention.

10A is a diagram illustrating a movement locus of a fourth group lens according to zooming, and FIG. 10B is a diagram illustrating block division at the time of controlling the fourth group lens according to zooming.

FIG. 11 is a diagram illustrating the first example of the present invention and illustrating a change in the position sensitivity of the fourth lens unit due to zooming.

Shows another blow <br/> click split during Figure 12 accompanying the magnification fourth group lens control.

[Explanation of symbols]

1 ... variator 8 ... focus lens 11 ...'s over arm encoder 12 ... zoom encoder reading circuit 13 ... first correction data 14 ... focus encoder 15 ... focus encoder reading circuit 16 ... second correction data 201 ... PSD 202 ... slit 203 … Infrared light emitting diode 204… PSD output reading circuit 208… correction data 303 variator 304… second group lens (variator) 305… zoom encoder (potentiometer encoder) 307… fourth group lens (focus lens) 308… focus encoder (Electric capacitance type encoder) 309 area data 310 speed data 311 correction data

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hiroyuki Takahara 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Naoya Kanada 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon (72) Inventor Hiroyuki Wada 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Shigeru Ogino 3-30-2, Shimomaruko 3-chome, Ota-ku, Tokyo Canon Inc. ( 56) References JP-A-61-245121 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02B 7/08, 7/10, 7/28

Claims (2)

(57) [Claims] 1. A variator that moves in the optical axis direction to change the magnification.
Lens for focusing by moving in the optical axis direction with the lens.
A varistor lens, and a variator lens.
Changes the position sensitivity of the focus lens
In a lens position control device provided with an optical system, the variator lens and the focus
Moving means for moving the lens, the variator lens, and position detection means for detecting the position of the focus lens, the output from the position detecting means variator lens,
A storage unit for storing correction data for correcting an error between each position of the focus lens and a design value; and the variator lens and the focus lens based on the output of the position detection unit and the correction data stored in the storage unit.
Calculating means for calculating each position of the lens, wherein the correction data is stored in the variator lens and the focus lens.
Correction of each lens position at multiple points within the lens movement range
A data, each lens of the correction data is obtained
Position depends on the position sensitivity of the focus lens.
A lens position control device, wherein a large number is set at a position where the position sensitivity is high . 2. A variator that moves in the optical axis direction to change the magnification.
Lens for focusing by moving in the optical axis direction with the lens.
A varistor lens, and a variator lens.
A lens position control device having an optical system in which the width of the depth of focus of the entire system changes with the change in the variator lens and the focus by electromechanical conversion
Moving means for moving the lens, the variator lens, and position detection means for detecting the position of the focus lens, the output from the position detecting means variator lens,
A storage unit for storing correction data for correcting an error between each position of the focus lens and a design value; and the variator lens and the focus lens based on the output of the position detection unit and the correction data stored in the storage unit.
Calculating means for calculating each position of the lens, wherein the correction data is stored in the variator lens and the focus lens.
Correction of each lens position at multiple points within the lens movement range
It is the data, before the correction data is required Symbol each Ren
Position changes as the variator lens changes magnification.
The focus according to the width of the depth of focus of the entire optical system.
A lens position control device characterized by setting many points in a narrow point depth range .