JPS6247011A - Optical vibration isolator - Google Patents

Abstract

PURPOSE:To prevent optical vibration with a simple constitution by allowing a correcting optical pat to move in parallel in a correct position by the dynamic pressure generated with a flow of liquid. CONSTITUTION:A correcting optical part 2 converges parallel rays of a luminous flux and is shifted to move an image and is stored airtightly in a lens barrel, and the extent of shift of the correcting optical part corresponds to that of the image on the image surface in 1:1. When the correcting optical part 2 receives a driving force to move momently to a suspended cylinder, dynamic pressures are generated between parallel plane glasses GO and GO' and parallel planes G and G' respectively, and automatic alignment and parallel movement are performed because they are in the same state with respect to longitudinal gaps. Thus, the dynamic pressure effect of the fluid is generated symmetrically before and after a suspended part to keep the degree of parallel and gaps.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field] The present invention relates to an optical vibration isolator, and in particular to a practical configuration of an active part for correcting image vibration.

〔Technical field〕

There has been an extremely high demand for optical image stabilization compared to the past.

BACKGROUND ART Shaking of a photographic screen is usually caused when a camera is moved to a car when photographing a sports event or a news report. Sports broadcasts or news programs are often shot with a video camera or cine camera, but in the case of a still camera, when hand-held shooting is carried out with a long focal length lens attached, images tend to blur. Therefore, it is best to use a tripod, but it cannot be denied that the ease of reproduction will deteriorate.

One of the known optical image stabilization devices employs a method in which an optical wedge is provided in the imaging system, and the deviation of the optical path due to vibration is corrected by changing the angle of the optical wedge and using its prism effect. Another device includes a reflecting mirror fixed by a gyro device with respect to spatial coordinates in the photographing system, and uses deflection of the optical path by the reflecting mirror to freeze the image. However, both devices tend to be significantly larger.

Not suitable for long-term handheld shooting.

Another method is to suspend the lens in a liquid such that the position of the lens is maintained relative to the spatial coordinates even if an external force is applied to the device. The purpose is to prevent image vibration using the suspension method. - For example, if a portion of the optical system is provided with a portion that can be freely displaced in a direction perpendicular to the optical axis, and this portion is displaced, the image on the image plane can be moved. Therefore, if the amount of displacement is determined so as to offset the movement of the image caused by camera shake, etc., it is possible to realize a photographic lens that does not suffer from camera shake.

In this case, the requirements for the suspension structure are (1) that the optical axis does not fall during displacement, (2) that there is no loss of friction or other driving force, and (3) that the lens that is displaced is It is possible to operate in dimensional directions.

In order to satisfy the above points, it is possible to configure the displacing part and other parts of the optical system with parallel planes and drive the displacing part, but the spacing and parallelism of the parallel planes should be adjusted to maintain optical performance. must be kept accurate. However, adjusting the spacing with mounting members or mechanically supporting the suspension lens barrel from the outside were not desirable methods in terms of increased friction and adaptability to two-dimensional movement.

The present invention solves the above-mentioned difficulties. By configuring the displacing part to be a plane parallel to the front part and the rear part, the two spaces can be symmetrical, and the spaces can be strictly controlled. What needs to be maintained is when correcting blur, and at this time, pay attention to the fact that the displaced part is moving.

And of a device in which part of the optical system is suspended in liquid,
A surface that is configured so that the suspended portion and the other portion form substantially parallel planes, and that this surface or the member that holds this surface has a portion in which the distance between opposing surfaces changes in the optical axis direction, and that the surface has a changing portion. Parallelism and spacing are maintained by the dynamic pressure effect of the fluid caused by the deviation between the suspended part and the opposing plane occurring symmetrically in front and behind the suspended part.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to the drawings. After the vibration isolating device is constructed, the characteristic parts of the present invention will be explained.

FIG. 1 is a sectional view showing the arrangement of main components within the lens barrel. 1amlj is a component lens of the 7-focal optical system of the telephoto lens, and cemented lenses if and Ig are focus lenses that perform focusing by moving back and forth. Reference numeral 2 denotes a correction optical unit that converges parallel light beams and moves an image by this shift, and the correction optical system is housed in a lens barrel in an airtight manner. The shift amount of the correction optical section and the shift amount of the image on the image plane are l:1. 3 and 3' are spacers 3d in the correction optical section 2.

A plunger S consisting of movable magnets 3a, 3a' coupled via 3d', coils 3b, 3b, and leaf springs 3c, 3c' that keep the movable magnets 3a, 3a' in position when not energized.
l is an acceleration sensor placed near the principal point of the lens that detects acceleration in a direction perpendicular to the optical axis and parallel to the plane of the paper. do. It is assumed that the plunger and the acceleration sensor are also arranged in a cross section including the optical axis in a direction perpendicular to the illustration in FIG. 1 in the same manner as in this figure. Reference numeral 4 represents an aperture aperture drive control unit, and 5 represents a focus drive and control unit that moves the focus lenses if and Ig. P is one of a group of contact points for exchanging focus information, aperture information, release information, etc. with the camera body (not shown), and F is an image plane determined by a silver halide film or a solid-state image sensor. The holding and driving structure of the correction optical section 2 is removable as shown in FIG.

FIG. 2 is a block diagram showing the entire system of this embodiment. 5a is a focus drive unit that moves the focus lenses lf and 1g to predetermined positions in response to a known camera focus control signal inputted from a contact Pi, and 5b is a focus position detection unit. Reference numeral 10 denotes an image movement acceleration calculation circuit caused by a shift of the photographing optical axis, which calculates the composite magnification β from the output signal of the focus position signal detection section 5b, multiplies this by the output of the acceleration sensor S1, and outputs the result. Reference numeral 20 denotes a calculation circuit for the movement acceleration of the image caused by rotation around the principal point of the optical axis. The output is weighted and output. These two signals are added by an adder circuit 40 to obtain the moving acceleration of the image. The calculation of each acceleration is described using a mathematical formula as follows.

(10) If the output of the acceleration sensor St is al, the output of the focus position detection unit 5b (=<extension amount) Movement acceleration a10 due to shift of
- to Xa1 (20) Output a1 of acceleration sensor S1, acceleration sensor S
If the output a2 of 2, the distance statement of the acceleration sensor 5IS2, the amount of extension Acceleration a2o= (x'+f) X (-al+a2)/cross 4
(R
ESET) Integrate the elapsed time starting from the time when voltage is applied to the input to obtain the amount of displacement of the image after the elapsed time from the time of reset. The integration start signal is OR
The shutter open signal (HIGH → LOW) given by the gate 90 and applied to contact P2 from the camera side, or the accumulation start signal (LOW, HIGH)
given according to. Note that this signal is maintained while being stored in the sensor.

This integration start signal is simultaneously applied to the switching circuit 100, and an image displacement amount signal is applied to the inverter 110 to the drive circuit 60 of the actuator 3 while the shutter is open or during the AF sensor's accumulation time. Note that PG is the GNO connection terminal between the lens and camera. The actuator drive circuit compares the output of the output inverter 110 of the position detection circuit 3C of the correction optical section 2, and energizes the coils 3b and 3b' of the actuator so that the output becomes zero. As a result, the correction optical section 2 is driven in the opposite direction by the displacement signal, and as mentioned above, since the shift amount of the correction optical section and the shift amount of the image on the image plane F are 1:1, the correction optical section 2 is driven in the opposite direction. The movement of the statue is IL
Melt. Further, the image acceleration signal is fed forward to the drive circuit 60, which performs predictive control and drives the actuator while referring to the actuator characteristic input circuit 70. The operation of this system is described below according to the camera operation sequence.

First, the system starts operating while the camera is stationary, then the first stroke of the shutter button is pressed to start the AF sequence, and the correction optical section operates while the AF sensor is storing data. , image blur is prevented. Furthermore, when the shutter button is pressed to the second stroke and released, image blur is prevented again while the shutter is open.The structure of the correction optical section will be described in detail with reference to FIG. FIG. 3 is a sectional view showing the structure of the correction optical section. 2b is the lens barrel of the shift lens.

Lens 01 assumed by C rings w, w' inside
~G, with parallel plane glasses Go, Go' at both ends
are airtightly fixed with adhesive. 2a is a suspension cylinder with parallel plane glasses G and G' at both ends and packing materials P and P'
The holding member 2d is fixed by rings 2C and 2C' through the lens driving members R and R'', which are integrally molded in the shape of a funnel with a shaft R2 at the bottom and made of a flexible material such as rubber.
, 2 d'' to form an airtight structure.Another pair of lens drive members and presser members are arranged symmetrically with the optical axis, resulting in a total of four lenses.These lens drive auxiliary members are attached to the shaft portion R2. It is connected to the plunger 3 at one end, and is engaged and connected to the lens barrel 2b at the tip R3 of the shaft part.The lens drive members R, R'' also have membrane parts that maintain the position of the correction optical part. I am accomplishing it.

The rigidity is large in the driving direction, but extremely small in the direction perpendicular to the driving direction.For example, the driving member R is an airtight lens barrel that provides almost no resistance to the driving force of the lens via the driving member R. A colorless, transparent, homogeneous liquid such as silicone oil is filled between the lens barrel and the airtight suspension tube to reduce or eliminate the influence of gravity acting on the lens barrel and act as a lubricant. By designing the lens barrel, the specific gravity of the lens section is made to approximately match the specific gravity of the liquid.The parallel plane glasses G and co, and between c' and Go' The end face of the parallel plane glass c (...
The chamfer is chamfered at a shallow angle to make it easier to lift off the surface.

In the above configuration, one plane of the parallel plane glass may be one side of the lens.

Therefore, the correction optical section 2 receives the driving force and moves toward the suspension cylinder.
When they momentarily move, dynamic pressure is generated between the parallel plane glasses GO, GO' and the parallel plane glasses G, G', respectively.
Since the state is the same at the front and rear intervals, self-centering is performed and parallel movement is realized.

FIG. 4 shows a modification of the inclined portion, and although only one side is depicted here, it is assumed that the inclined portion is formed both before and after the correction optical portion.

Figure (A) shows that the edge of the lens barrel 2b to which the parallel plane glass Go is fixed is given a slope opposite to that of the above embodiment, and Figure CB) shows the protrusion of the lens barrel 2b and the parallel plane glass Go. The structure has a continuous slope.

It is also possible to provide a gently curved surface instead of an inclined surface.

(Effects) The present invention described above focuses on the liquid unique to the liquid suspension method, and although it has a fixed configuration, it is possible to move the correction optical part in parallel at the correct position using the dynamic pressure generated by the flow of the liquid. It has the effect of

Additionally, optical image stabilization was achieved with a simple configuration.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an embodiment of the present invention, Fig. 2 is a block diagram of its pre-correction system, Fig. 3 is a perspective view of the correction optical section, and Fig. 4 is a diagram showing the main parts of a modified example. .

Claims (1)

[Claims] A device in which a part of the optical system is suspended in liquid,
Optical vibration isolation characterized in that the suspended part and the other part are parallel planes, and this surface or the member holding this surface is provided with a part in which the distance between opposing surfaces changes in the optical axis direction. Device.