JPH0534560A - Lens barrel - Google Patents

Abstract

PURPOSE:To make a lens barrel light in weight and to reduce the cost thereof by disusing a dedicated guide pole. CONSTITUTION:A screw pole 3 which is rotatably supported in the lens barrel 5 in parallel with an optical axis, a potentiometer 1 which is disposed on the opposite side to the pole 3 in the lens barrel 5 by interposing the optical axis so as to make the moving direction of a slide part 1a in parallel with the optical axis, a moving ring 2 which holds a variable power lens L and which is obtained by screwing a screw hole 2a provided on one side to the pole 3 and engaging an engagement part 2b provided on the other side with the slide part 1a, and a driving source 4 which gives rotational force to the pole 3 are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens barrel for a video camera or other camera using a potentiometer to detect the position of a variable power lens.

[0002]

2. Description of the Related Art In order to reduce the size and weight of current video cameras, rear focus drive lens barrels that can be made smaller and lighter are becoming the mainstream.

FIG. 10 is a front view showing a conventional rear focus drive lens barrel, and FIG. 11 is a side view thereof. Figure 1
0, in FIG. 11, 1 is a potentiometer provided so that the moving direction of the slider portion 1a is in the optical axis direction, 2 is a concave portion 1a-of the slider portion 1a for holding the variable power lens L.
A moving ring 3 having an engaging portion 2b that engages with 1 is a moving ring 2
Screw rod 2 which has a screw 3a to be screwed into the screw sleeve 2a and is rotatably supported in the lens barrel in parallel with the optical axis. Guide rods 7 and 8 which engage and support the concave portion 2c of the ring 2 are spur gears which are fixed to the screw rod 3 and the output shaft 4a of the motor 4 and mesh with each other.

With the above structure, when the motor 4 operates, the power of the motor rotates the screw rod 3 via the output shaft 4a and the spur gears 7 and 8. For this reason, the moving ring 2 receives a moving force via the screw 3a of the screw rod 3 and the screw sleeve 2a to perform zooming movement in the optical axis direction. During this zooming movement, the moving ring 2 moves along the guide rod 6 and therefore does not tilt, and image blurring and image blurring due to backlash in the radial direction are prevented.

[0005]

However, in the above-mentioned conventional example, since the guide rod 6 is used, there are restrictions on the compact product design of the lens barrel, and there are disadvantages in terms of weight and cost. was there.

The present invention has been made to solve the above problems, and an object thereof is to make it possible to design a compact product without using a dedicated guide rod.

[0007]

A lens barrel according to the present invention includes a threaded rod 3 rotatably supported in the lens barrel in parallel with the optical axis.
And a potentiometer arranged on the opposite side of the screw rod with the optical axis sandwiched in the lens barrel so that the moving direction of the slide portion is parallel to the optical axis, and a variable magnification lens is held on one side. By providing a moving ring in which the provided screw hole is screwed into the screw rod and the engaging portion provided on the other side is engaged with the slider portion, and a drive source for applying a rotational force to the screw rod , The dedicated guide bar can be eliminated, and the weight and cost can be reduced.

[0008]

Embodiments of the present invention will now be described with reference to the drawings. 1 is a front view, FIG. 2 is a side view, FIG. 3 is a perspective view, and FIGS. 1 to 3 are drawings which best show the features of the present invention. In the figure, 1 is a potentiometer in which the base plate 1b is fixed to the lens barrel 5 with screws or the like so that the moving direction of the slider portion 1a is the optical axis direction. Screw sleeve 2 on one side parallel to the optical axis
A moving ring 3 having a and an engaging portion 2b which engages with the recess 1a-1 of the slider portion 1a on the other side, has a screw 3a screwed into the screw sleeve 2a, and has a mirror 3 parallel to the optical axis. A screw rod 4 is rotatably supported in the cylinder 5, 4 is a motor, and 7 and 8 are spur gears fixed to the screw rod 3 and the output shaft 4a of the motor 4 and meshing with each other. The lens barrel 5 has the engaging portions 2 of the moving ring 2 on both sides of the movement path of the slider portion 1a.
Ribs 5a are provided which abut and guide at both ends of b.

In the above structure, when the motor 4 operates, the power of the motor 4 causes the screw rod 3 to rotate via the output shaft 4a and the spur gears 7 and 8. Therefore, the moving ring 2 receives a moving force through the screw 3a of the screw rod 3 and the screw sleeve 2a to move in the optical axis direction for zooming. During this zooming movement, the engaging portion 2b of the moving ring 2, the slider portion 1a of the potentiometer 1 and the rib 5a of the lens barrel 5 prevent the moving ring 2 from tilting, and tilt the image due to backlash in the radial direction. Is prevented by a contact guide between the moving ring engaging portion 2b and the rib 5a of the lens barrel. Further, the shake of the image during zooming is regulated by the engagement between the moving ring 2, the screw sleeve portion 2a having a one-piece structure, the slider portion 1a of the potentiometer 1 and the engaging portion 2b of the moving ring 2. (Other Embodiment) FIGS. 4 and 5 show a second embodiment in which the shape of the engaging portion 1a on the potentiometer 1 side of the first embodiment shown in FIGS. 1 to 3 is changed to a spherical shape, When the engaging portion is a flat surface as in the above embodiment, surface accuracy is required,
The spherical shape stabilizes the engagement without requiring dimensional accuracy.

FIG. 6 shows a third embodiment in which the engaging portion 2b of the moving ring 2 is spherical, and the engaging portion 2b of the moving ring 2 is attached to the rib 5a formed on the lens barrel 5 as in the previous embodiment. The twisting that occurs when they are brought into surface contact is eliminated, and the movement of the moving ring 2 becomes smooth.

FIG. 7 shows a fourth embodiment in which the rib 5a of the lens barrel 5 in each of the above-mentioned embodiments is omitted and the moving ring 2 is guided by the slider portion 1a of the potentiometer 1.
As shown in FIG. 8, the slider portion 1 of the potentiometer 1
a is the case 1c of the potentiometer 1 where the sliding portion 1a slides so that the backlash is pressed,
The structure is guided by 1d, and the image shake direction during zooming is restricted.

FIG. 9 shows a fifth embodiment in which the rib 5a provided on the lens barrel 5 has a spherical tip shape, and the surface precision of the engaging portion is relaxed as in the embodiment shown in FIG. As a result, it is possible to prevent the movable ring 2 from swinging or twisting during zooming.

[0013]

As described above, since the slider portion of the potentiometer is also used as the guide of the moving ring, the potentiometer can be housed in the lens barrel, and there are few restrictions on compact product design. Become. Also,
By eliminating the dedicated guide rod, weight reduction and cost reduction can be achieved.

[Brief description of drawings]

FIG. 1 is a front view showing a lens barrel according to a first embodiment of the present invention.

FIG. 2 is a side view showing the lens barrel of FIG.

FIG. 3 is a perspective view showing the lens barrel of FIG.

FIG. 4 is a front view showing a lens barrel according to a second embodiment of the present invention.

5 is a side view showing the lens barrel of FIG. 4. FIG.

FIG. 6 is a front view showing a lens barrel according to a third embodiment of the present invention.

FIG. 7 is a front view showing a lens barrel according to a fourth embodiment of the present invention.

8 is a cross-sectional view of a potentiometer in the lens barrel of FIG.

FIG. 9 is a front view showing a lens barrel according to a fifth embodiment of the present invention.

FIG. 10 is a front view showing a conventional lens barrel.

11 is a side view showing the lens barrel of FIG.

[Explanation of symbols]

1 Potentiometer 1a slide part 2 moving rings 2a Screw hole (screw sleeve) 2b Engagement part 3 screw rod 4 motor (driving source) 5 lens barrel 5a rib

Claims (5)

[Claims] 1. A screw rod 3 rotatably supported in the lens barrel so as to be rotatable in parallel to the optical axis, and the optical axis being sandwiched in the lens barrel so that a moving direction of a slide portion is parallel to the optical axis. The potentiometer arranged on the opposite side of the screw rod and the screw hole provided on one side for holding the variable power lens are screwed into the screw rod and the engaging portion provided on the other side is engaged with the slider portion. A lens barrel including a moving ring and a drive source that applies a rotational force to the screw rod. 2. The lens barrel is provided with a rib that abuts and guides a moving ring that moves in the optical axis direction.
The lens barrel described. 3. The lens barrel according to claim 1, wherein the engaging portion of the moving ring that engages with the slider portion of the potentiometer is spherical. 4. The lens barrel according to claim 1, wherein either one of the abutting portions of the moving ring and the rib of the barrel has a spherical shape. 5. The lens barrel according to claim 1, wherein a guide portion for guiding the movement of the slider portion in the optical axis direction is provided inside the potentiometer.