JP2002049069A - Anti-vibration zoom lens device and camera system - Google Patents

Abstract

(57) [Summary] [Problem] To prevent vignetting on the wide-angle side due to a delay in following of the image blur correction optical system during a high-speed zooming operation from the telephoto side to the wide-angle side. SOLUTION: In an image stabilizing zoom lens apparatus having an image blur correction optical system for correcting image blur on the image side of a lens group moving at the time of zooming, the image blur is wider than a predetermined zoom ratio Z1. The maximum image movement amount capable of correcting the image blur by the correction optical system does not exceed a predetermined value, and the zoom ratio Z1 and the predetermined zoom ratio Z2 on the telephoto side of the zoom ratio Z1.
The maximum image movement amount becomes larger than the predetermined value and gradually increases.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-shake zoom lens apparatus and a lens system having a function of correcting image blur caused by vibration of a photographing optical system, and more particularly to an image side of a variable magnification moving lens group and a focusing moving lens group. Image blur correction optical system arranged,
For example, a film camera, a TV camera, and a video camera that perform an image blur correction operation using a variable apex angle prism (variable angle prism, VAP), a shift lens (an image blur correction lens group that moves in a direction substantially orthogonal to the photographing optical axis), or the like The present invention relates to an anti-vibration zoom lens device and a camera system suitable for such applications.

[0002]

2. Description of the Related Art When a photographing optical system vibrates due to camera shake, wind, or the like, image blur occurs on an image forming surface. Conventionally, a zoom lens apparatus having a function of correcting this image blur, particularly an image stabilizing zoom lens apparatus in which an image blur correction optical system such as a variable apex prism or a shift lens is arranged closer to the image side than the variable power moving lens group, Various proposals have been made to reduce the size and weight of the blur correction optical system, which is advantageous for reducing the size and power saving of the drive system.

When the displacement angle of the photographing optical system due to vibration is θ and the focal length is f, the amount of image blur (image movement) ΔY with respect to an object at infinity is ΔY = f · tan θ. . . It is represented by (1). Therefore, even with the vibration at the same displacement angle θ, the image movement amount ΔY changes in proportion to the focal length, and the image moves greatly on the telephoto side, but becomes smaller as it goes to the wide-angle side, and becomes inconspicuous on the screen. . This tendency becomes more pronounced as the zoom ratio increases.

Next, a displacement amount ΔS (correction amount) of the image blur correction optical system for canceling out the image movement amount ΔY is represented by ΔS = − △, where dy is the image movement sensitivity of the image blur correction optical system. Y / dy = −f · tan θ / dy. . . (2) can be expressed.

FIG. 17 is a view showing a lens arrangement of an example of a four-group image stabilizing zoom lens apparatus, and FIGS. 18 to 20 are optical path diagrams at the wide-angle end, the intermediate range, and the telephoto end. F is a fixed focus lens group during zooming operation, V is a variator that moves linearly during zooming, C is a compensator that moves nonlinearly for image point correction, SP is an aperture, and R is an imaging function. , And Rr is a rear lens group.
The variator V and the compensator C constitute a zoom optical system (variable-moving lens group). IS is an image blur correction optical system, and is shown as a shift lens. IE is a focal length conversion optical system (extender), and a plurality of conversion magnifications can be inserted into and removed from the photographing optical axis.
P is a color separation prism, an optical filter, or the like, and is shown as a glass block in FIG.

As shown in FIGS. 18 to 20, the off-axis principal ray height HB in the focus lens unit F and the variator V is high on the wide angle side and low on the telephoto side. Therefore, the image circle, which is a range where vignetting does not occur, is narrow on the wide-angle side and wide on the telephoto side. This tendency becomes more pronounced as the magnification ratio increases.

In such a zoom lens, if the maximum displacement △ SMAX of the image blur correction optical system IS is constant over the entire zoom range, a focus lens is required to secure a sufficient image circle so as not to cause vignetting on the wide angle side. It is necessary to increase the diameter of the group F and the variator V, and the entire system becomes large.

Therefore, on the wide-angle side where the image quality improvement effect by the image blur correction is small, the maximum displacement △ SMAX is set small, the effective diameter of the required focus lens unit F is reduced, and the size is reduced. By setting the displacement amount こ と が SMAX to be large, it is conceivable to obtain a large anti-vibration effect. A method of changing the maximum displacement △ SMAX of the image blur correction optical system IS according to the zooming state and the focusing state as described above is proposed in, for example, Japanese Patent Application Laid-Open No. 5-66450.

[0009]

By the way, a high-power zoom lens having a magnification of more than 20 times for broadcasting can perform a high-speed zooming operation of 1 second or less from a telephoto end to a wide-angle end. It is very difficult to change the maximum displacement △ SMAX of the image blur correction optical system IS following such a high magnification and high speed zooming operation. In particular, when zooming from the telephoto side to the wide-angle side at a high speed, image blurring occurs. The displacement amount ΔS of the correction optical system IS cannot follow the zooming operation, and exceeds ΔSMAX on the wide-angle side, and the optical performance deteriorates, the asymmetry of the peripheral light amount becomes remarkable, and vignetting occurs. There was a problem that it would.

(Object of the Invention) An object of the present invention is to prevent vignetting on the wide-angle side due to a delay in following of the image blur correction optical system during high-speed zooming from the telephoto side to the wide-angle side. An object of the present invention is to provide a vibration zoom lens device and a camera system.

[0011]

In order to achieve the above object, the present invention provides an image stabilizing zoom having an image blur correction optical system for correcting image blur on the image side of a lens group which moves during zooming. In the lens apparatus, on the wide angle side of the predetermined zoom ratio Z1, the maximum image movement amount that can be corrected by the image blur correction optical system does not exceed a predetermined value, or on the wide angle side of the predetermined zoom ratio Z1. In the present invention, the maximum image movement amount at which image blur correction by the image blur correction optical system can be performed is controlled within a range where the effective light flux is not vignetted by a specific component member of the anti-shake zoom lens apparatus, and A fold ratio Z1;
The maximum image movement amount becomes larger than the predetermined value or a value on the wide-angle side from the zoom ratio Z1 between a predetermined zoom ratio Z2 on the telephoto side of the zoom ratio Z1 and
It is characterized by gradually increasing.

Further, the present invention has an image blur correction optical system for correcting image blur on the image side of the lens unit moving at the time of zooming, and the image blur correction optical system on the wide angle side from a predetermined zoom ratio Z1. The maximum amount of image movement that can be corrected by the correction optical system does not exceed a predetermined value, or the maximum amount of image movement that can be corrected by the image blur correction optical system on the wide angle side from a predetermined zoom ratio Z1. Is set so that the effective light flux is controlled by a specific component of the anti-vibration zoom lens device so as not to be vignetted, and the predetermined zoom ratio Z1 and a predetermined zoom ratio on the telephoto side with respect to the zoom ratio Z1. An anti-shake zoom lens device wherein the maximum image movement amount becomes larger than the predetermined value or a value on the wide angle side of the zoom ratio Z1 and gradually increases between the zoom ratio Z2 and the zoom ratio; Signal between the anti-vibration zoom lens and It is an camera system comprising a camera for.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As an image blur correction optical system, there are a variable apex prism and a shift lens, but a shift lens system is adopted as an example, and when a subsystem in the optical system is decentered in a direction orthogonal to the optical axis. The 23rd Applied Physics Lecture (1962)
(Year) based on the method presented by Matsui.

A part of the photographing lens group p is flattened by E.
The aberration amount △ ′ Y of the entire system when the line is decentered is
As shown in the equation (a), the aberration amount ΔY before eccentricity and the eccentricity
And the sum of the generated eccentric aberration ΔY (E). here
The eccentric aberration ΔY (E) is the first-order eccentricity as shown in the equation (b).
Coma (IIE), first-order decentered astigmatism (III
E) Primary eccentric field curvature (PE), primary eccentric distortion
Difference (VE1), first-order eccentric distortion additional aberration (VE2), 1
It is represented by the next origin movement (△ E). Also, the expression (c)
The aberrations from (IIE) to (△ E) in equations (h) are
Decentered lens group for paraxial rays when the focal length is normalized to 1
The angle of incidence and the angle of emergence of the on-axis marginal ray to_p ,
α_p ′, And the incident angle and the exit angle of the principal ray passing through the center of the pupil are ￣
(Α_p ), ￣ (α _p ’), The eccentric lens group
Aberration coefficient I_p , II_p , III_p , P_p , V_p And partial
Aberration coefficient I of the lens system on the image side of the center lens group_q , II
_q , III_q, P_q , V_q Is represented by

[0015]

(Equation 1)

The same equation is used for the case of tilted eccentricity such as a variable apex angle prism. Of these, the primary origin movement (△ E) represents the image movement due to the eccentricity, and the image movement amount Y (E) is expressed as R = 0 and tanω =
0, α _k ′ = 1 (R is the entrance pupil diameter, ω is the angle of view, α _k ′ is the on-axis marginal conversion inclination angle), and Y (E) = − (１ ／) E · (△ E) = E (Α _p ′ −α _p ) (3) Accordingly, the image movement sensitivity dy of the image blur correction optical system IS _{is such} that (△ E) _is the primary origin movement of the image blur correction optical system IS, and α _is , α _is the converted inclination angle before and after the image blur correction optical system IS. Dy = − (１ ／) · (△ E) _is = − (α _is ' −α _is ) (4) The maximum image movement amount △ YMAX that can be corrected by the image blur correction optical system IS is obtained by adding △ YMA to Y (E) in equation (3).
The maximum displacement 最大 SMAX in X and E, and d in (α _p ′ -α _p )
By substituting y, ΔYMAX = △ SMAX · dy (5) By defining the maximum image movement amount △ YMAX from equation (5), the maximum displacement amount △ SMAX of the image blur correction optical system IS can be defined.

As shown in FIG. 1, when an image blur correction optical system IS is provided on the image side of the variable power moving lens group (variator V and compensator C), the focus lens group F and the variable power moving lens group V are used for variable power. , C form an image point I '
Does not change, the image movement sensitivity dy of the image blur correction optical system IS is considered in consideration of the image forming relationship of only the relay lens group R, since the arrangement and the paraxial tracking value are constant regardless of zooming.
Is a constant.

Next, a specific configuration of the image stabilizing zoom lens device according to one embodiment of the present invention will be described.

<Numerical Embodiment 1> As an example, FIG. 2 shows a numerical embodiment 1 of the optical system at the wide-angle end as shown in FIG. In FIG. 17, a focus lens unit F is a front lens unit having a positive refractive power as a first unit, and a variator V is a lens unit having a negative refractive power for zooming as a second unit. Is monotonously moved to the image plane side to perform zooming from the wide-angle end to the telephoto end. The compensator C is a lens group having a positive refractive power, and moves non-linearly to the object side on the photographing optical axis in order to correct an image plane variation due to zooming. The relay lens group R is a lens group having a positive refractive power as a fourth group, and is fixed.

Next, the features of the fourth group of relay lens units R in Numerical Data Example 1 will be described. The fourth relay lens group R includes an image blur correction optical system IS having a negative refractive power, a focal length conversion optical system IE, and a rear lens group R having a positive refractive power.
The image blur correction optical system IS has a function of moving in a direction perpendicular to the photographing optical axis for image blur correction. The image blur correction optical system IS is composed of two negative lenses and one positive lens.

The decentering aberration coefficients corresponding to the equations (c) to (h) are represented by p, the lens group of the image blur correction optical system IS, and q, the lens group of the image blur correction optical system IS on the image side. Is as shown in FIG.

From FIG. 3, it can be seen from the equation (4) that the image movement sensitivity dy of the image blur correction optical system IS is dy = − (1/2) · (ΔE) = − 0.848. . . (6) Since the image point I ′ (FIG. 1) formed by the lens units F, V, and C does not change over the entire zooming range, considering the imaging relationship of only the relay lens unit R, its arrangement and paraxial tracking value are The image movement sensitivity dy of the image blur correction optical system IS is a constant since it is constant regardless of the magnification. Therefore, the image movement amount △ Y due to the vibration of the displacement angle θ (vibration angle),
The displacement amount ΔS (correction amount) of the image blur correction optical system IS for correcting the image blur is ΔY = f · tan θ. . . (7) ΔS (f) = − ΔY / dy = −f · tan θ / (− 0.848). . . (8).

From the equation (2), it can be seen that when the sensitivity dy of the image blur correction optical system IS is high, the image blur correction effect can be obtained with a small amount of displacement ΔS. Blur remains. Such image blur remains particularly in a format having a small image size such as a 2/3 type or 1/2 type used in a broadcast camera and a 1/3 type or 1/4 type used in a consumer video camera. It becomes more noticeable. In addition, the image quality becomes more conspicuous on the screen as the image quality becomes higher, such as in HDTV. Therefore, by restricting the image movement sensitivity dy of the image blur correction optical system IS to 1 or less, the maximum image movement amount △ YMAX can be set to a predetermined range (particularly in the range from the wide-angle end to the zoom ratio Z1 (focal length 40 mm)). For example, when the image is held in the range including 0), image blur is prevented from occurring.

In the first embodiment, the image circle allowance YIMG at each zoom position and the maximum image movement amount that can be corrected.
YMAX, the maximum displacement amount of the image blur correction optical system △ SMAX,
FIG. 4 shows the maximum vibration angle θMAX that can be corrected. The image circle allowance YIMG includes a maximum image height Y0MAX at which the luminous flux at the minimum aperture can reach, and a radius Y of an imaging surface of a CCD or the like.
0, YIMG = Y0MAX-Y0. . . (9) can be obtained as When the maximum image movement amount △ YMAX exceeds YIMG, vignetting occurs on the screen.

YIMG is small on the wide angle side and large on the telephoto side. For example, when image blur correction is performed at the telephoto end, the displacement ΔS of the image blur correction optical system IS is as large as −0.91 mm even at a small vibration angle θ = 0.1 deg. Here, when the magnification is rapidly changed to the wide-angle end, the image blur correction optical system IS
Cannot follow, and exceeds YIMG on the wide-angle side, causing vignetting.

FIG. 5 shows a reference state (△ S =
FIG. 6 shows the optical path diagram at the wide angle end △ S =
The optical path diagram at 0.91 mm is shown. In FIG. 6, the image height +
It can be seen the light flux corresponding to 5.5m are eclipsed by the lens support member S ₁ of the first lens group 1. Sometimes eclipsed be similarly by the lens support member S ₂ of the second first lens group.

Therefore, as shown in FIGS. 4 and 7, in this embodiment, the focal length f1 = 40 mm and the zoom ratio Z1 = 4.
On the wide-angle side, the maximum image movement amount ΔYMAX that can be corrected by the image blur correction optical system IS is set to zero, and the focal length f1 =
From 40 mm, the focal length f2 on the telephoto side is f2 = 100 m
m, maximum displacement in the range of zoom ratio Z2 = 10１０SMAX
By gradually increasing (= △ YMAX / dy), the image blur correction optical system IS is forcibly returned to the photographing optical axis center position (reference position = centering position) when the magnification is changed to the wide angle side at high speed, Vignetting is prevented.
In FIG. 7, the image circle margin YIMG of FIG. 4 is plotted and shown. As can be seen from FIG. 7, since the characteristic curve of the maximum image movement amount △ YMAX does not exceed the plotted image circle margin amount YIMG, no vignetting occurs.

The maximum displacement △ SMAX (= △ YMAX /) of the image blur correction optical system IS on the wide-angle side of the zoom ratio Z1 = 4.
dy) is not limited to zero, but may be a predetermined value near zero within a range not exceeding the image circle margin YIMG as shown in FIG.

In the range of the zoom ratio Z1 to Z2, the maximum
Displacement △ Second derivative of SMAX ｛d^TwoΔSMAX / d (l
ogZ)^Two Make sure that the sign of｝ is not inverted
That is, the maximum image movement amount that can be corrected △ the second derivative of YMAX ｛d
^Two ΔYMAX / d (logZ) ^Two The sign of｝ is inverted to negative
So that the following equation is satisfied:^Two ΔYMAX / d (logZ)^Two > 0 (10) The maximum image movement amount characteristic is particularly changed in the range of the zoom ratios Z1 to Z2.
Connect smoothly at the point of magnification ratio Z1 and the point of zoom ratio Z2.
By this, the image blur correction optical system IS at the time of high-speed zoom operation
Smooth behavior is the center of the shooting optical axis
Desirable to be able to return to position.

That is, since the focal length of the photographing optical system increases approximately exponentially with respect to the moving amount of the variator V,
When deciding a function, it is desirable to evaluate the sign inversion by performing a second derivative with logZ. By satisfying the expression (10), the maximum image movement amount △ YMAX in the range from the zoom ratio Z2 to the telephoto side and the range from the zoom ratio Z1 to the wide angle side is more smoothly connected, and at the time of high-speed zooming to the wide angle side, The image blur correction optical system IS can be more smoothly held at the photographing optical axis center position. .

Further, on the telephoto side from the zoom ratio Z2 = 10, the maximum image movement amount .DELTA.YMAX is regulated so that the correctable maximum vibration angle .theta.MAX becomes substantially constant. As a result of the verification, if the change in the maximum vibration angle θMAX due to the magnification change is within 20%, that is, within a range that satisfies the following equation (11), the magnification position that can be corrected even with the same vibration angle θ and the change that cannot be completely corrected It is possible to prevent the difference between the double positions from being conspicuous and causing a sense of incongruity on the screen.

0.8 ≦ (Z / ZT) / (△ YMAXT / △ YMAX) ≦ 1.2 (11) In the equation (11), ZT is a zoom ratio at the telephoto end,
Z is a certain zoom ratio, ΔYMAXT is the maximum image movement amount at the zoom ratio ZT, and ΔYMAX is the maximum image movement amount at the zoom ratio Z.

When equation (11) exceeds the upper or lower limit,
The difference between the variable power position that can be corrected even at the same vibration angle θ and the variable power position that cannot be corrected becomes noticeable, and a sense of discomfort is generated on the screen.

In general, not only the magnification state but also the focusing state changes, the imaging magnification before and after the focus lens unit F changes, so that the angle of view and the optical path in the optical system change, and vignetting occurs. The state changes. At this time, the maximum image movement amount △ YMAX (or the maximum displacement amount △ SMAX) is multiplied by the change amount due to the focusing state as a coefficient, or the maximum image movement amount △ YMAX (or the maximum displacement amount △ SMAX) is held in a table. May be. When a focal length conversion optical system IE (extender) with a conversion magnification of k times is inserted on the photographing optical axis,
Since the angle of view tanθ on the image changes by a factor of 1 / k, it is desirable to reduce the maximum correctable vibration angle ΔθMAX to about 1 / k accordingly.

When the focusing state in Numerical Embodiment 1 changes, the off-axis principal ray height HB in the focus lens unit F as the front lens unit changes, so that the image circle margin YIMG changes. FIG. 9 shows the image circle margin YIMG at each zoom position at an object distance of 3.4 m.
Is shown.

From FIG. 9, the image circle margin YIM is shown.
It can be seen that G is slightly smaller than at infinity. If the maximum image movement amount 移動 YMAX is multiplied by the rate of change of the image circle margin YIMG due to the focused state or the rate of change of the angle of view due to the focused state as a coefficient, it is possible to cope with the case where the focused state changes. it can. Next, FIG. 10 is a block diagram of a camera system suitable for broadcasting, comprising a vibration-proof zoom lens device and a video camera according to one embodiment of the present invention.

The camera system shown in FIG. 10 includes an anti-shake zoom lens device 1 and a video camera 2. The anti-shake zoom lens device 1 has a CPU 28, and the video camera 2 has a CP.
U40 are provided respectively. The CPU 40 of the video camera 2 and the CPU 28 of the image stabilizing zoom lens device 1
The signal exchange between the camera and the lens is performed by performing the serial communication. An image formed by the image stabilizing zoom lens device 1 is formed on a CCD 41 serving as an image sensor of the video camera 2, charges are sequentially read from the CCD 41, and the charges pass through a video signal processing circuit 42. Are output as video signals by the video output circuit 43.

The anti-vibration zoom lens device 1 includes a focus optical system 24 and a zoom optical system 26. The focus optical system 24 is connected to the focus lens group F of the first group in FIG. Numeral 26 corresponds to a variable power moving lens group composed of a second group variator V and a third group compensator C in FIG.

A focus position sensor 25 is disposed in the focus lens group 24, and a zoom position sensor 27 is disposed in the zoom optical system 26.
The signal from 5 is converted into a digital signal by an AD converter 44 for reading a focus position, and the signal from the zoom position sensor 27 is converted into a digital signal by an AD converter 45 for reading a zoom position. With the focus position sensor 25 and the zoom position sensor 27, the positions of the focus optical system 24 and the zoom optical system 26 can be read. Behind the zoom optical system 26, there is an image blur correction optical system 3, and FIG.
Image blur correction optical system I of the fourth group relay lens group R
It corresponds to S. A voice coil motor 15 is provided for moving the image blur correction optical system 3 in the horizontal direction (yaw direction) perpendicular to the photographing optical axis, and a voice coil motor 5 is provided for moving in the vertical direction (pitch direction). The yaw control DA converter 20 and the servo amplifier 19 are configured to drive the voice coil motor 15 in the yaw direction, and the pitch control DA converter 10 and the servo amplifier 9 are configured to drive the voice coil motor 5 in the pitch direction. Have been.

The yaw position detecting sensor 16 is used for detecting the position in the yaw direction when the image blur correction optical system 3 shifts.
However, a pitch position detection sensor 6 is provided for position detection in the pitch direction.

A yaw angular velocity sensor 18 serves as a detector for detecting yaw vibration applied to the lens, and a pitch angular velocity sensor 8 serves as a detector for detecting vibration in the pitch direction.
1, AD converter 23, pitch filter 11, AD
A converter 13 is configured. The displacement angle can be read by integrating the angular velocity taken into the CPU 28.

The voice coil motor 15, the yaw position detecting sensor 16 and the yaw angular velocity sensor 18
And a voice coil motor 5, a pitch position detection sensor 6 and a pitch angular velocity sensor 8
Is composed.

Next, a rotatable extender holding member 30 is provided behind the image blur correction optical system 3, and includes a first extender 31 (conversion magnification 1x), a second extender 32 (2x), and a third extender. 33 (1.5
x) and four of the fourth extenders 34 (0.8x) are held, and one of them is selectively switched and used. The extender selected here corresponds to the focal length conversion optical system IE in FIG. The light beam that has passed through the extender is then imaged by the CCD 41. Note that an extender having a conversion magnification of 2.7 times may be further added, or may be replaced with any of the extenders.

At present, the CCD 4 is adjusted according to the aspect ratio of the screen.
There is a camera system that changes the readout area of No. 1. In a 2/3 inch CCD, the image circle is φ11 mm when the aspect ratio is 16: 9 and φ9 mm when the aspect ratio is 4: 3.
The readout area is set as an image circle. With this setting, the 16: 9 CCD 41 can be realized by cutting off the horizontal to 4: 3 size. However, up to now, the aspect ratio of 4: 3 at the image size of φ11 has been the standard in the camera, and when the extender serving as the reference is the same, the image size φ9 has a larger φ than the image size φ11.
11 / φ9 ≒ This is an image enlarged by a factor of 1.2. To cope with this, an image size conversion optical system for converting the range of φ11 mm into φ9 mm is prepared on the lens side, so that the system can be used in the same manner as the φ11 image size of 4: 3. It becomes possible.
Therefore, in the present embodiment, the standard image circle of the image stabilizing zoom lens device 1 is φ11 mm, and the reference extender is the first extender 31 (1x). On the other hand, when the image circle is φ9 mm, the reference extender is φ9 / φ1 as an image size conversion optical system.
1 ≒ 0.8x, which is based on the fourth extender 34 (0.8x). However, the second extender 32 (2x) and the third extender 33
(1.5x) is an image circle of φ11mm,
For the first reference extender 31 (1x), 2
x, 1.5x, but in the image circle of φ9 mm, the reference fourth extender 34 (0.
8x), 2x / 0.8x = 2.5x, 1.5x /
It acts as an extender for 0.8x = 1.875x. In the image circle of φ9 mm, the first extender 31 (1x) is 1x / 0.8x = 1.25 with respect to the reference fourth extender 34 (0.8x).
Acts as an extender for x. Conversely, in the case of φ11, if the fourth extender 34 (0.8x) is used, vignetting will appear in the image, so that use is prohibited.

A motor 36 is provided to rotationally drive the extender holding member 30 so that the extender can be switched electrically. The video camera 2 is provided with an extender control switch 39 and an image circle changeover switch 38. Inputs from these switches 38, 39 are taken into the CPU 40. The CPU 40 transmits the extender switching signal and the image seek switching signal to the image stabilizing zoom lens device 1 through serial communication with the CPU 28 of the image stabilizing zoom lens device 1. In addition, the first extender 31, the second
The positions of the extender 32, the third extender 33, and the fourth extender 34 are detected by an extender position detection sensor 37, and the extender position signal is input to the CPU 28. The CPU 28 outputs an extender switching control signal to the drive amplifier 35 according to the extender switching signal, the image circle switching signal, and the extender position signal.
Is performed.

The CPU 28 has a nonvolatile memory ROM 2
9, a correction coefficient for calculating a correction amount (movement amount) of the image blur correction optical system 3 with respect to a displacement angle (vibration angle) obtained by angle detection is stored in a data table based on a zoom position and a focus position. Is stored as Further, a data table for limiting the movement of the image blur correction optical system 3 after calculating the amount of correction in the yaw direction and the pitch direction of the image blur correction optical system 3 is stored.

FIG. 11 is a correction coefficient data table used when calculating the correction amount (displacement amount) of the image blur correction optical system 3 with respect to the displacement angle. In the equation (8), the correction coefficient is a function of an arbitrary focal length and an arbitrary object distance, C (Z, F), in equation (8) so that the correction coefficient can be calculated at an arbitrary focal length and an arbitrary object distance. ), The correction coefficient of the image blur correction optical system 3 with respect to the displacement angle in the yaw direction is Axx (x = 0, 1, 2,...).
., N), the correction coefficient of the image blur correction optical system 3 with respect to the displacement angle in the pitch direction is Bxx (x = 0, 1, 2,...,
n). The data table in FIG. 11 includes correction coefficients Axx and Bxx corresponding to zoom position data and focus position data. Here, the zoom position data normalizes the value from the zoom position sensor 27, and the wide-angle end (WIDE) is 0 and the telephoto end (TELE) is 0xff.
ff and the value expressed in hexadecimal notation and the focus position data normalize the value from the focus position sensor 25, and use a value expressed in hexadecimal notation of 0 for the nearest end (NEAR) and 0xffff for the infinite end (FAR).

FIGS. 12 to 15 show correction amount restriction data tables for restricting the movement of the image blur correction optical system 3 when each extender is inserted. Limit value data for limiting the correction amount in the yaw direction of the image blur correction optical system 3 when the image size is φ11 is Cxx (x = 0, 1, 2,...,
i,..., j,..., n), and limit value data for limiting the correction amount in the pitch direction of the image blur correction optical system 3 is Dxx.
(X = 0, 1, 2,..., I,..., J,..., N). Limit value data for limiting the correction amount in the yaw direction of the image blur correction optical system 3 when the image size is φ9 is Exx (x = 0, 1, 2,..., I,.
., N), the limit value data for limiting the correction amount of the image blur correction optical system 3 in the pitch direction is Fxx (x = 0, 1,
2, ..., i, ..., j, ..., n).

When the zoom position data on the correction amount restriction data table is from 0 (WIDE) to 0x3000 (Z1), the restriction value data for restricting the correction amount in the yaw direction and the pitch direction is set to 0. This “0” means that the image blur correction optical system 3 is electrically held at the center of the photographing optical axis. Also, if the zoom position data is 0x3000 (Z
From 1) to 0x6000 (Z2), the limit value data for limiting the correction amount in both the yaw direction and the pitch direction is set to data that gradually increases (Z1-Z2 in FIG. 7).
See curve between). And the zoom position data is 0x60
From 00 (Z2) to 0xffff (TELE), limit value data for limiting the correction amount in both the yaw direction and the pitch direction is defined as data such that the maximum vibration angle at which image blur correction can be performed is substantially constant (FIG. 7 (see the curve on the telephoto side from Z2).

The values of Cxx, Dxx, Exxx, and Fxx are numerical values calculated from the above-described method for obtaining the numerical example. FIG. 12 shows the first extender 31 (1
x), FIG. 13 is the second extender 32 (2x), FIG. 14 is the third extender 33 (1.5x), FIG.
Is a correction value limit data table for the fourth extender 34 (0.8x), and is a limit value Cxx, Cxx, of the image blur correction optical system 3 corresponding to the zoom position data and the focus position data.
Dxx, Exxx, and Fxx data. The zoom position data and the focus position data are the same normalized data as in FIG.

Next, FIG. 16 shows a schematic flowchart for calculating a correction amount for driving the image blur correction optical system 3.

It is checked whether the extender switching control signal is equal to the extender position (step S).
1) If not equal, extender rotation switching control is started (step S2). After the switching of the extenders is completed (step S3), the angular velocity signals input from the angular velocity sensors 8 and 18 are integrated (step S4).
A displacement angle is obtained (step S5). Based on the displacement angle, the zoom position data, and the focus position data, the image blur correction optical system 3 using the correction coefficient of the data table in FIG.
Is calculated (step S6). When the correction amount obtained by the calculation exceeds the limit value in the data tables of FIGS. 12 to 15, the correction amount is limited by the limit value of the data table (step S7). Interpolated values are used as values between table data. Thereafter, the correction amount that has passed through the restriction processing is output to the DA converters 10 and 20 (step S8).

According to the above flow, the pitch direction correction amount and the yaw direction correction amount of the image blur correction optical system 3 are independently calculated.
The pitch direction correction amount is input to the servo amplifier 9 after being converted into an analog value by the DA converter 10. Also,
The output signal of the pitch position detection sensor 6 is also input to the servo amplifier 9, and the position control of the image blur correction optical system 3 in the pitch direction is performed based on the difference signal between the correction amount and the detection output of the pitch position detection sensor 6. The yaw direction correction amount is also converted to an analog value by the DA converter 20 and then input to the servo amplifier 19. The output signal of the yaw position detection sensor 16 is also input to the servo amplifier 19, and the position control of the image blur correction optical system 3 in the yaw direction is performed based on the difference signal between the correction amount and the detection output of the yaw position detection sensor 16.

[0054]

As described above, according to the present invention,
On the wide angle side of the predetermined zoom ratio Z1, the maximum image movement amount that can be corrected by the image blur correction optical system does not exceed a predetermined value, or on the wide angle side of the predetermined zoom ratio Z1, the image blur correction optical system is used. The maximum image movement amount that can be corrected by the system
The effective light flux is controlled by a specific component of the image stabilizing zoom lens device in a range where no vignetting occurs, and a predetermined zoom ratio Z1 and a predetermined zoom ratio Z2 on the telephoto side of the zoom ratio Z1. The maximum image movement amount becomes larger than the predetermined value or the value on the wide-angle side from the zoom ratio Z1 and gradually increases. At the time of zooming operation, it is possible to prevent vignetting on the wide angle side due to a delay in following of the image blur correction optical system.

Further, for example, by setting the predetermined value to zero, vignetting on the wide-angle side can be better prevented.

Further, for example, the maximum image movement amount に お い て YMAX between the variable power ratio Z1 and the variable power ratio Z2,
By satisfying d ² ΔYMAX / d (logZ) ² > 0, the image blur correction optical system can be moved to the vicinity including the photographing optical axis during the high-speed zooming operation from the telephoto side to the wide-angle side. It is possible to smoothly return to the reference position.

Further, for example, the maximum image movement amount △ YMAX
On the telephoto side of the zoom ratio Z2, when a certain zoom ratio is Z, a zoom ratio at the telephoto end is ZT, and a maximum image movement amount at the telephoto end is △ YMAXT, 0.8 ≦ (Z / ZT) / (△ YMAXT / △ YMAX)
By satisfying ≦ 1.2, it is possible to prevent a feeling of strangeness on the screen.

Further, for example, by using a data table stored in a storage medium in advance to control the maximum image movement amount that can be corrected, the maximum image movement amount that can be corrected can be easily controlled. be able to.

[Brief description of the drawings]

FIG. 1 is an optical conceptual diagram of an image stabilizing zoom lens device in a case where an image blur correction optical system is arranged on the image side of a variable power moving lens group.

FIG. 2 is a numerical example 1 according to one embodiment of the present invention.
FIG.

FIG. 3 is a diagram illustrating each eccentric aberration coefficient in the case of Numerical Example 1.

FIG. 4 is a diagram illustrating a maximum image movement amount and the like at each zoom position in Numerical Example 1.

FIG. 5 is an optical path diagram in a reference state at a wide angle end according to an embodiment of the present invention.

FIG. 6 is an optical path diagram in a certain image blur correction state at a wide-angle end according to an embodiment of the present invention.

FIG. 7 is a diagram illustrating a maximum image movement amount characteristic with respect to a focal length according to an embodiment of the present invention.

FIG. 8 is a diagram illustrating another maximum image movement amount characteristic with respect to a focal length according to an embodiment of the present invention.

FIG. 9 is a diagram showing a margin amount of an image circle at each zoom position at an object distance of 3.4 m in Numerical Example 1.

FIG. 10 is a block diagram illustrating a configuration of a camera system according to one embodiment of the present invention.

FIG. 11 is a diagram showing a data table of a correction coefficient with respect to a vibration angle in one embodiment of the present invention.

FIG. 12 is a diagram illustrating a data table for an extender (1x) that determines the maximum amount of movement of an image blur correction optical system for image blur correction in one embodiment of the present invention.

FIG. 13 is a diagram illustrating a data table for an extender (2x) that determines the maximum amount of movement of the image blur correction optical system for image blur correction in one embodiment of the present invention.

FIG. 14 is a diagram illustrating a data table for an extender (1.5x) that determines the maximum amount of movement of an image blur correction optical system for image blur correction in one embodiment of the present invention.

FIG. 15 is a diagram illustrating a data table for an extender (0.8x) that determines the maximum amount of movement of an image blur correction optical system for image blur correction according to an embodiment of the present invention.

FIG. 16 is a flowchart showing an outline of operation control in one embodiment of the present invention.

FIG. 17 is a lens cross-sectional view showing an example of the arrangement of the optical system portion of the vibration reduction zoom lens device at infinity at the wide angle end.

18 is a diagram illustrating an off-axis principal ray height HB at the wide-angle end of the image stabilizing zoom lens device in FIG.

19 is a diagram showing an off-axis principal ray height HB in an intermediate region of the image stabilizing zoom lens device of FIG.

20 is a diagram illustrating an off-axis principal ray height HB at the telephoto end of the image stabilizing zoom lens device in FIG.

[Explanation of symbols]

F focus lens group V variator C compensator R relay lens unit IS image blur correction optical system IE the focal-length-changing optical system (extender) Rr group after the relay lens S _1, S ₂ lens support member Z1, Z2 zoom ratio 1 antivibration zoom Lens device 2 Video camera 3 Image blur correction optical system 5, 15 Voice coil motor 6 Pitch position detection sensor 16 Yaw position detection sensor 8 Pitch angular velocity sensor 18 Yaw angular velocity sensor 24 Focus optical system 25 Focus position sensor 26 Zoom optical system 27 Zoom position Sensor 28, 40 CPU 29 ROM 31 First extender (1x) 32 Second extender (2x) 33 Third extender (1.5x) 34 Fourth extender (0.8x) 35 Drive amplifier 36 Motor 37 Extender Position sensor 38 image circle changeover switch 39 extender control switch 41 CCD

Continued on the front page (72) Inventor Katsuhiko Nagata 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term (reference) 2H087 KA01 MA12 NA07 PA15 PA16 PB20 QA02 QA07 QA17 QA21 QA25 QA34 QA42 QA45 RA32 RA41 SA43 SA47 SA49 SA53 SA55 SA63 SA64 SA72 SA75 SA76 SB07 SB15 SB27 SB36 SB47

Claims (16)

[Claims] 1. An image stabilizing zoom lens apparatus having an image blur correction optical system that corrects image blur on the image side of a lens group that moves during zooming, wherein the image is zoomed on a wide angle side from a predetermined zoom ratio Z1. The maximum image movement amount at which image blur correction by the blur correction optical system is possible does not exceed a predetermined value, and the zoom ratio Z1 and a predetermined zoom ratio Z2 on the telephoto side with respect to the zoom ratio Z1.
Wherein the maximum image movement amount becomes larger than the predetermined value and gradually increases. 2. The image stabilizing zoom lens device according to claim 1, wherein the predetermined value is zero. 3. An anti-vibration zoom lens apparatus having an image blur correction optical system for correcting image blur on the image side of a lens group moving at the time of zooming, wherein the image is zoomed on a wide angle side from a predetermined zoom ratio Z1. The maximum image movement amount capable of image blur correction by the blur correction optical system is controlled such that the effective luminous flux is not vignetted by a specific component of the anti-shake zoom lens device,
In addition, the maximum image movement amount becomes larger than the value on the wide angle side of the zoom ratio Z1 between the zoom ratio Z1 and a predetermined zoom ratio Z2 on the telephoto side of the zoom ratio Z1. ,
An anti-vibration zoom lens device characterized by gradually increasing. 4. The apparatus according to claim 1, wherein the maximum image movement amount smoothly changes at the zoom ratio Z1 and the zoom ratio Z2. Anti-vibration zoom lens device. 5. The anti-vibration zoom lens device according to claim 3, wherein the specific component is a lens support member. 6. The specific component is a first component of a photographing optical system.
6. The anti-shake zoom lens device according to claim 5, wherein the vibration-proof zoom lens device is a group of lens support members. 7. The specific component is a second component of the photographing optical system.
6. The anti-shake zoom lens device according to claim 5, wherein the vibration-proof zoom lens device is a group of lens support members. 8. When a certain zoom ratio is Z with respect to the maximum image movement amount ΔYMAX between the zoom ratios Z1 and Z2, d ² ΔYMAX / d (logZ) ² > 0. The image stabilizing zoom lens device according to any one of claims 1 to 7, wherein the following condition is satisfied. 9. The maximum image movement amount ΔYMAX is a certain magnification ratio Z, a magnification ratio at the telephoto end is ZT, and a maximum image movement amount at the telephoto end on the telephoto side of the zoom ratio Z2. △ YM
Assuming AXT, 0.8 ≦ (Z / ZT) / (ＭＡYMAXT / △ YMAX)
The image stabilizing zoom lens device according to any one of claims 1 to 8, wherein the following condition is satisfied. 10. The anti-shake zoom lens device according to claim 1, wherein the image movement sensitivity dy of the image blur correction optical system is 1 or less. 11. When the focal length conversion optical system is inserted on the photographing optical axis, the maximum image movement amount capable of correcting image blur is changed according to the conversion magnification of the focal length conversion optical system. The image stabilizing zoom lens device according to claim 1. 12. The image stabilizing zoom according to claim 1, wherein a data table stored in a storage medium is used to control the maximum image movement amount capable of correcting image blur. Lens device. 13. The image stabilizing zoom lens device according to claim 12, wherein the data table has data corresponding to a zoom ratio. 14. When there are a plurality of focal length converting optical systems, the data table is provided for each focal length converting optical system.
3. The anti-shake zoom lens device according to 3. 15. The image stabilizing zoom lens device according to claim 1, wherein the image blur correction optical system is a shift lens that moves in a direction perpendicular to a photographing optical axis. 16. A camera system comprising: the image stabilizing zoom lens device according to claim 1; and a camera that performs signal communication with the image stabilizing zoom lens device.