JP2803896B2 - Optical equipment - Google Patents

Description

The present invention relates to an optical device such as a still camera, a video camera, a cine camera or a lens barrel applicable to all cameras used industrially or commercially. It is.

[Prior Art] As is well known, in an optical apparatus having an optical system for changing a focusing action and a focal length, means for moving a part or all of a lens system in an optical axis direction is required. For this movement, a DC motor, a stepping motor or the like is generally used as an actuator, and a guide mechanism by fitting a bar sleeve or a barrel member is used to move the lens system in the optical axis direction. The driving force of the actuator is transmitted to the lens support mechanism by a transmission mechanism such as a deceleration gear, a timing belt, or a feed screw.

[Problems to be Solved by the Invention] As described above, the guide for holding and moving the lens is mechanically slidable, for example, between the bar sleeve and the guide or on the surface of the lens barrel member. There is a part, and there is a certain amount of clearance in the sliding part, so that when the lens moves, there will be bumps, surface fall, width fluctuation,
For this reason, there is a problem that image quality is degraded and image shaking occurs. In addition, since the friction of the sliding portion is large, a relatively large motor must be used, so that there is a problem that downsizing cannot be performed, and noise and vibration are large.

SUMMARY OF THE INVENTION An object of the invention according to the present application is to provide an optical device that can support a lens element without frictional resistance due to sliding, does not cause backlash due to engagement, and can accurately detect the position of the lens element with good responsiveness. It is intended to provide.

[Means for Solving the Problems] The configuration of an optical device for realizing the object of the invention according to the present application includes a lens barrel, a lens element arranged in the lens barrel, and a lens element in the lens barrel. An elastic member attached concentrically to the lens barrel and movably supporting the lens element by elastic displacement in the optical axis direction;
A detection unit that is directly attached to the elastic member and detects distortion of the elastic member due to movement of the optical element in the optical axis direction.

[Operation] In the optical apparatus having the above-described configuration, the lens element can be supported by the elastic member so as to be movable in the optical axis direction without play or backlash. The lens position is detected by detecting the distortion of the elastic member.

[Embodiment] In practicing the present invention, it is desirable to use a flat plate member as the elastic member, and cut out the concentric or ring-shaped elastic flat plate. This is because displacement in the direction of the optical axis is facilitated.

An embodiment of the present invention will be described below with reference to the accompanying drawings.

Now, referring to FIGS. 1 and 2, it is easily understood that the lens holding frame 3 is disposed inside the lens barrel outer tube 7, and the lenses 4a and 4b are fixed to the holding frame. You.

The lens holding frame 3 is supported inside the barrel outer tube 7 by two elastic flat plates, for example, gimbal springs 1 and 2. Elastic plate
1, 2 have concentric cutouts 10 as shown in FIG. Therefore, as shown in FIG. 3, when there is only one elastic flat plate, the holding frame 3
Moves freely in the illustrated Z, θ, and ψ directions.
However, it is held with a relatively strong force in the x and y directions.
Therefore, if two elastic flat plates are arranged in parallel as shown in FIG. 4 and the lens holding frame 3 is fixed, the holding frame 3 cannot move or rotate in the x, y, θ and ψ directions, but moves only in the Z direction. Will be possible.
FIG. 4A shows a case where the elastic flat plates 1 and 2 are in an equilibrium state, and FIG. 4B shows a state where the holding frame 3 is moved in the Z direction.

A permanent magnet 9 for driving the holding frame in the optical axis direction is fixed or embedded in an outer peripheral portion of the lens holding frame 3. Or it is magnetized. Further, a magnet configured by winding the coil 6 around the iron core 5 is arranged corresponding to the permanent magnet 9.

The elastic flat plates 1 and 2 are formed by etching from, for example, phosphor bronze or rust-free steel plate, or are manufactured at low cost by a plastic molded product, and a strain gauge 8 as a moving distance detecting means is attached to a part thereof.

Since the present embodiment is configured as described above, when the coil 6 is energized, a magnetic field is generated around the iron core 5, and by changing the energized state, that is, the polarity of the electromagnet, the magnetic field is generated between the coil 6 and the permanent magnet 9. A suction force and a repulsive force are generated. Therefore, the holding frame 3 to which the permanent magnet 9 is fixed moves in the optical axis direction by obtaining a propulsive force with respect to the outer cylinder 7. Therefore, the lenses 4a and 4b move in the optical axis direction, and the focusing or the focal length can be adjusted. Further, at this time, since the strain gauge 8 is mounted on the elastic flat plate, when the holding frame 3 moves in the optical axis direction, the amount of deformation of the elastic flat plate 1 can be directly detected. It is possible to detect the axial movement amount.

FIG. 5 shows another embodiment of the elastic flat plate. According to the present embodiment, the cutout portion 10 is formed in the shape of a tom.
That is, it is cut out so that the diameter is gradually increased.
The elastic flat plate of the present embodiment is used in the same manner as the flat plate shown in FIG. 1 and has the same effect. However, according to the present embodiment, the deformed arm portion 1a is longer than that of FIG. The lens can be moved with a light driving force, and the power of the actuator is small.

FIG. 6 shows an embodiment in which one elastic flat plate is used. That is, the lens holding frame 3 is supported at one end by the elastic flat plate 1, and the outer periphery 3a at the other end is supported by a plurality of guide rollers 50 and 51 so as to be movable in the axial direction.

According to the present embodiment, the aforementioned θ,
Since the movement in the ψ direction is regulated by the guide rollers 50 and 51, the holding frame 3 can be moved only in the optical axis direction, similarly to the embodiment using two elastic flat plates.

The other components are denoted by the same reference numerals, and redundant description will be avoided. Although not shown in the drawings, it is obvious that the present invention can be implemented by a guide pin, a bar sleeve, or the like instead of the guide roller.

[Effects of the Invention] As described above, according to the present invention, the lens element can be supported without frictional resistance due to sliding, without rattling, backlash, and the like due to fitting, and the position of the lens element can be changed in response. Good and accurate detection.

Further, since the detection means is directly attached to the elastic member, it is possible to provide an optical device such as a lens barrel having a small shape, a low cost, and a good response.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a first embodiment of the present invention, and FIG.
FIG. 1 is a plan view showing the first embodiment of the elastic flat plate as viewed from the direction of arrows II-II in FIG. 1, FIG. 3 is a perspective view for explaining the operation of the present embodiment, and FIG. (B) is a perspective view showing an operation state in which the elastic flat plates are in different states, and FIG.
The figure is a plan view showing another embodiment of the elastic flat plate, and FIG. 6 is a sectional view showing a second embodiment of the present invention. 1, 2 ... elastic flat plate, 3 ... lens holding frame, 4a, 4b ... lens, 5 ... iron core, 6 ... coil, 8 ... strain gauge, 9 ... permanent magnet.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G03B 3/10 G02B 7/04

Claims (1)

(57) [Claims] 1. A lens barrel, a lens element disposed in the lens barrel, and mounted concentrically with respect to the lens barrel in the lens barrel, wherein the lens element is disposed in the optical axis direction. An elastic member that is movably supported by elastic displacement, and a detecting unit that is directly attached to the elastic member and detects distortion of the elastic member accompanying movement of the optical element in the optical axis direction. Optical equipment.