JP3165727B2 - Image stabilizer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in an image blur correction device using a variable apex angle prism used in an optical instrument.

[0002]

2. Description of the Related Art In recent years, automation of photographing apparatuses such as still cameras and video cameras has been advanced, and apparatuses having an automatic focus adjustment mechanism as well as an automatic exposure have been put into practical use and widely used.

Further, a technique for realizing a function of correcting an image blur caused by a blur at the time of photographing of the photographing apparatus has been put to practical use.

An image blur correction device added to a photographing device is
In general, a shake detecting means for detecting shake of the entire photographing apparatus,
A blur correction means for correcting blur, a driving means for driving the blur correction means, a control means for calculating a blur correction amount according to the amount of blur detected by the blur detection means, and controlling the driving of the driving means; Consists of

[0005] The above driving means generally has a pitch (up and down,
Pitch driving means for performing a correction drive for a vertical (direction) motion and yaw drive means for performing a correction drive for a yaw (left and right, horizontal) motion. In addition, a variable apex angle prism (VAP) is often used as the shake correction unit. The variable apex prism has a pair of two transparent plates,
A bellows portion made of a transparent film that seals these two transparent plates at the outer peripheral portion, and a transparent liquid having a high refractive index filled in a space formed by the pair of transparent plates and the bellows portion, Are rotatably supported by mutually orthogonal rotation axes, and the mutually orthogonal rotation axes are driven by the pitch drive means and the yaw drive means to correct image blur.

[0006]

In an image blur correction apparatus using a variable apex angle prism as described above, a pair of transparent plates of the variable apex angle prism are driven by a driving shaft to provide a support shaft provided in a direction orthogonal to each other. When rotating as an axis, the optical axes of a pair of transparent plates are manufactured out of alignment due to manufacturing variations, and if the optical axes are forcibly aligned by the holding frame, the transparent plates are driven when the transparent plates are driven. Circumferential torsion occurs in the sealed bellows portion, which causes correction distortion and lowers the performance in image blur correction.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image blur correction device capable of preventing a reduction in image blur correction performance in view of the above points.

[0008]

Means for Solving the Problems To achieve the above object,
In the present invention, the outer diameter of a pair of transparent plates facing each other is bellows.
Space formed by liquid-tight connection by the parts
A variable apex prism filled with a transparent liquid;
A pair of transparent plates that hold the outer diameter of the pair of transparent plates at the inner diameter
A holding frame, and at least one of the holding frames is paired with the other.
Driving means for rotating and deflecting the passing light beam
In the image blur correction device, an inner diameter portion of the pair of holding frames and
A fitting portion of the outer diameter of the transparent plate, one is less engaging portion of the gap allowance, the other is a large fitting portion of the gap allowance, the holding frame in the fitting portion of the larger the gap allowance An image blur correction device in which an adhesive for bonding an inner diameter portion and an outer diameter portion of the transparent plate is an elastic adhesive.
It is.

[0009]

FIG. 1 is a sectional view of an optical system having an image blur correction device according to an embodiment of the present invention. FIG. 2 is an exploded view showing a blur correction mechanism and a drive mechanism of the image blur correction device of FIG. It is a perspective view.

In FIG. 1, reference numeral 1 denotes a photographing lens;
Is a blur correction mechanism. A fixed front lens group 12 and a variator lens group 1 are provided in a lens barrel 11 of the taking lens 1.
3, a fixed lens group 14 and a focusing (compensator) lens group 15 are accommodated.

Also, in the shake correction mechanism 2, 21a,
Reference numeral 21b denotes a pair of two transparent plates facing each other, and a space sealed by the transparent plates 21a and 21b and the bellows-shaped transparent film 22 sealing the outer peripheral portion thereof includes:
It is filled with a transparent liquid (not shown) having a high refractive index, and these constitute a variable apex angle prism 23.

The variable apex angle prism 23 includes transparent plates 21a and 21a.
1b and the inner diameter of the holding frames 24a and 24b, and the transparent plate 21 is provided on the inner diameter of the holding frames 24a and 24b.
Inner diameter fitting portions 24c and 24d that fit with the outer diameters of a and 21b
One of the inner diameter fitting portions (in the embodiment, the inner diameter fitting portion 24d of the holding frame 24a) has a larger gap than the outer diameter of the transparent plates 21a and 21b. .

When assembling the variable apex angle prism 23, first, the transparent plates 21a and 21b and the bellows-shaped transparent film 22 are bonded. Next, a transparent liquid having a high refractive index is sealed. The completed variable apex angle prism 23 is fitted to the inner diameter fitting portion 24c of the holding frame 24b and fixed with an adhesive, and the support shafts 26b and 2 are inserted into the holes 27b and 27c of the fixed cylinder 27.
5b is inserted and assembled. Next, an elastic adhesive is applied to the inner diameter fitting portion 24d of the holding frame 24a, and the support shafts 26a and 27d are inserted into the holes 27a and 27d (not shown) of the fixed cylinder 27.
25a is inserted and assembled. The support shafts 25a and 26a
The support shafts 2 are provided at a diagonal of 180 degrees from each other.
5b and 26b are also provided at a diagonal of 180 degrees from each other.

The support shafts 25a and 25b inserted into the holding frames 24a and 24b are provided on a fixed barrel 27 connected to the lens barrel 11 of the photographing lens 1 and at right angles to the optical axis O.
a, 24b circumferentially open holes 27a (not shown), 2
The rotary shaft 7b is rotatably supported with a rotation axis different from each other by 90 degrees, and is tiltably supported in a certain range in a circumferential direction perpendicular to the optical axis O. On the other hand, the support shafts 26a and 26b
Are inserted into the holes 27c and 27d (not shown) formed in the holes. The holes 27a and 27b are also provided at a diagonal of 180 degrees from each other.

The support shafts 25a, 25b are
7 are urged in the axial direction by leaf springs 28a (not shown) and 28b, which are urging means attached to the arm.

The holding frame 2 on the subject side, that is, the front side (pitch side), on which the support shafts 25a and 26a are horizontally supported.
On the support shaft 26a side of the flat coil 29a, as a pitch driving means, a flat coil 29a is fixed to a holding frame 24a, and a magnet 30a and a yoke are formed so as to form a closed magnetic circuit facing both surfaces of the flat coil 29a. 31a and 32a are arranged. In order to rotate the pitch-side holding frame 24a about the support shaft 25a and the support shaft 26a, a shake amount on the pitch side of the photographing apparatus is calculated by a shake detecting unit (not shown), and the coil 29a is corrected to correct the shake amount. A torque is generated by an electromagnetic force by flowing an electric current, and the transparent plate 21a inclines in a vertical direction by rotating the holding frame 24a,
The image blur in the pitch (vertical, vertical) direction is corrected by changing the refractive index of the variable apex angle prism 23.

An arm 34a having a slit 33a is fixed to the support shaft 26a side of the holding frame 24a, and a light emitting element 35a and a light receiving element 36a are arranged so as to sandwich the arm 34a. The light beam projected from the light emitting element 35a passes through the slit 33a and is irradiated on the light receiving element 36a. Here, the light emitting element 35a is an infrared light emitting element such as an IRED, and the light receiving element 36a is a photoelectric conversion element such as a PSD whose output changes depending on the position of a spot of a received light beam. The holding frame 24a, that is, the slit 33a of the arm portion 34a, the light emitting element 35a, and the light receiving element 36a,
The amount of rotation of the transparent plate 21a in the pitch direction is detected, and feedback control for rotating the holding frame 24a until a predetermined correction amount is obtained is performed.

Although not shown in FIGS. 1 and 2, the rear (yaw side) holding frame 24b is also provided with a flat coil, like the front (pitch side) holding frame 24a.
A magnet, a yoke, a slit, an arm, a light-emitting element, and a light-receiving element are arranged, and these function in exactly the same way as on the pitch side to correct image blur in the yaw (left, right, lateral) direction.

The subject side (front side) of the variable apex angle prism 23
Is provided with a protective cover 38 to which a protective glass 37 is attached, and the protective cover 38 is integrally attached to the lens barrel 11 of the photographing lens 1 or a photographing apparatus main body (not shown).

In the above-described embodiment, the shake correcting mechanism 2
Has been described as an example provided integrally with the photographing lens 1, but the shake correction mechanism 2 may be configured as a single unit and added to the photographing apparatus as an adapter.

[0021]

As described above, according to the present invention,
One of the fitting portions between the inner diameter portion of the pair of holding frames and the outer diameter portion of the transparent plate is a fitting portion with a small clearance, the other is a fitting portion with a large clearance, and the fitting with the larger clearance is used. The adhesive for bonding the inner diameter portion of the holding frame and the outer diameter portion of the transparent plate in the joint portion is an elastic adhesive, even when the optical axis of the opposing transparent plate is shifted during assembly. This is absorbed by the fitting portion having the larger clearance and the elastic adhesive so that the bellows portion attached to the transparent plate is prevented from being twisted in the circumferential direction.

Therefore, it is possible to prevent the performance of image blur correction from being reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an optical system including an image blur correction device according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view of an image blur correction mechanism and a driving mechanism of the image blur correction device according to one embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photographing lens 2 Blur correction mechanism 11 Lens barrel 21a, 21b Transparent plate 22 Transparent film 23 Variable vertex angle prism 24a, 24b Holding frame 24c, 24d Inner diameter fitting part 25a, 25b, 26a, 26b Support shaft

Claims (1)

(57) [Claims] 1. A space formed by connecting the outer diameter portions of a pair of transparent plates facing each other with a bellows portion in a liquid-tight manner,
A variable apex prism filled with a transparent liquid, a pair of holding frames for holding the outer diameter portions of the pair of transparent plates at the inner diameter portion, and rotating at least one of the holding frames with respect to the other.
In the image blur correction device having a driving unit for moving and deflecting the passing light beam, a fitting portion between the inner diameter portion of the pair of holding frames and the outer diameter portion of the transparent plate is fitted with one having a small clearance. And the other part is a fitting part having a large clearance, and an adhesive for bonding the inner diameter part of the holding frame and the outer diameter part of the transparent plate in the fitting part having the larger clearance is elastic. An image blur correction device, characterized in that the adhesive has an adhesive.