JPH0728777Y2 - Viewfinder's diopter adjustment device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a diopter adjusting device for a viewfinder applied to a video camera, in which a diopter adjusting lens is moved and adjusted in the optical axis direction. .

[Outline of device]

The present invention provides a diopter adjusting device for moving and adjusting a diopter adjusting lens of a viewfinder in an optical axis direction in a lens barrel,
By having a spiral groove and dividing the rotating cylinder that adjusts the movement of the lens in the optical axis direction by rotation into a plurality of parts in the circumferential direction, and holding these in a cylindrical shape from the outer circumference with a cylindrical elastic body, This is intended to improve productivity.

[Conventional technology]

The applicant of the present invention has previously filed, for example, Japanese Utility Model Application No. 57-168861 as a prior application example of a viewfinder diopter adjustment device applied to a video camera.

In this prior application example, a rotating cylinder is rotatably arranged inside a lens barrel (outer cylinder), a diopter adjusting lens is arranged inside the rotating cylinder, and a pair of guided projections provided on the outer circumference of the lens. Through the pair of spiral grooves provided in the rotating cylinder in a spiral shape and inserted into the pair of linear grooves parallel to the optical axis direction provided on the inner circumference of the lens barrel, and the guided projection, the spiral groove and the linear groove are inserted. Constitutes a guide mechanism.

Then, by rotating and adjusting the rotating cylinder, the lens is moved and adjusted by the guide mechanism in the optical axis direction, and the diopter of the image captured by the video camera is adjusted.

After the diopter adjustment, the rotary cylinder is screwed into the open end of the lens barrel and tightened by the tightening ring to fix the rotary cylinder.

[Problems to be solved by the device]

However, since the rotary cylinder of the prior application has a structure in which a pair of spiral grooves is provided in a complete cylindrical member, the spiral groove must be undercut in die casting or injection molding, and the processing cost is extremely high. Expensive. Therefore, under the present circumstances, a rotary cylinder is machined by cutting from a round bar or pipe material, but the productivity is poor, and it is not profitable with a low-priced model viewfinder. Further, since the rotating cylinder is built in the lens barrel, there is a problem that the assembly is very troublesome.

An object of the present invention is to provide a diopter adjusting device for a viewfinder, which is easy to process a rotary cylinder and is easy to assemble.

[Means for Solving the Problems]

In order to achieve the above object, a diopter adjusting device for a viewfinder according to the present invention comprises a lens barrel, a diopter adjusting lens disposed inside the lens barrel, and a rotatably disposed outside the lens barrel. Guided protrusions provided on the outer circumference of the lens are guided by the rotating cylinder, the spiral groove provided in the rotating cylinder in a spiral shape, and the linear groove provided in the lens barrel in parallel with the optical axis direction. And a guide mechanism for moving and adjusting the lens in the optical axis direction by the rotation of the rotary cylinder, and the rotary cylinder is composed of a plurality of divided cylinders circumferentially divided into a cylindrical shape. An elastic body holds the plurality of divided cylinders in a cylindrical shape from the outer circumference.

[Action]

Since the viewfinder diopter adjusting device configured as described above is configured by the divided cylinder in which the rotary cylinder having the spiral groove is divided into a plurality of pieces in the circumferential direction, each divided cylinder does not undercut the spiral groove. It is possible to perform injection molding and the like extremely easily. Further, the rotary cylinder can be assembled very simply by fitting a plurality of split cylinders to the outside of the lens barrel and then covering the outer circumference with a cylindrical elastic body.

〔Example〕

Hereinafter, an embodiment of a diopter adjusting device of a viewer finder in which the present invention is applied to a portable video camera will be described with reference to the drawings.

First, FIG. 8 shows the entire portable video camera, and a shoulder rest member 2, a lens 3, a hanging handle 4, a viewfinder 5 and the like are attached to the entire camera 1. Then, the viewfinder 5 is attached to the handle 4 and the CRT is placed inside the viewfinder body 6.
(Cathode ray tube) 7 and the like are housed, and a mirror 9 is housed in a rotary joint 8 that is rotatably mounted at the opening end of the viewfinder body 6 and a diopter adjustment device mounted at the opening end of the rotary joint 8. A diopter adjusting lens 11 is housed in the diopter adjusting device 10, and an eye cap 12 is attached to the open end of the diopter adjusting device 10.

Then, at the time of video recording, one eye of a cameraman is put on the eye cap 12, the photographed image reproduced on the CRT 7 and reflected by the mirror 9 is magnified by the lens 11. At this time, the lens 11 is moved and adjusted in the optical axis direction a by the diopter adjusting device 10 so as to match the diopter of the cameraman.

Next, the details of the diopter adjustment device 10 will be described with reference to FIGS. 1 to 7.

First, as shown in FIG. 1, a cylindrical lens barrel 14 made of synthetic resin or the like is provided with a pair of flange portions on the outer periphery of both ends thereof.
15 and 16 are integrally provided, and a connecting portion 17 to the rotary joint 8 is integrally provided at one end side. This lens barrel 14
Is provided with a pair of linear grooves 18 parallel to the optical axis direction a at opposing positions of 180 °, and an annular slit 19 is provided on the outer periphery of one flange portion 15. The outer circumference of the lens 11 arranged inside the lens barrel 14 is held by an annular lens holder 20 formed of synthetic resin or the like, and a pair of outer circumferences of the lens holder 20 are provided at opposing positions of 180 °. The guided projection 21 is attached by a pair of screws 22. The rotary cylinder 23 rotatably arranged outside the lens barrel 14 is assembled by semi-cylindrical split cylinders 24 and 25 which are circumferentially divided into two. These divided cylinders 24, 25 are formed of synthetic resin or the like, and a pair of spiral grooves 26 having a spiral shape with respect to the optical axis direction a are provided at 180 ° opposite positions on their inner peripheral surfaces. Then, the dividing surface 2 of these dividing cylinders 24, 25
A pair of dowels 29 and a dowel hole 30 for connection are integrally provided on 7, 28, and a pair of flange portions 31, 32 are integrally provided on the outer circumferences of both ends of the divided cylinders 24, 25. There is.
A cylindrical elastic body 33 that holds the rotating cylinder 23 from the outer circumference is formed of rubber or the like, and knurls 34 for preventing fingers from slipping are formed on the outer peripheral surface. A pair of rotating rings 35 and 36 fitted on the outer circumferences of both ends of the lens barrel 14 are formed of synthetic resin or the like, and a part of these rotating rings 35 and 36 in the circumferential direction is cut by a cutting portion 37. Has been done. These rotating rings 35, 36
A pair of small protrusions 39 are integrally provided at opposing positions of 180 ° on the surfaces facing each other in the optical axis direction a. 25 split planes 27,
It is provided at both axial ends of 28. The annular portion 42 of the eye cap 12 is integrally provided with an annular rib 43 which is fitted into the slit 19 of the lens barrel 14.

The diopter adjusting device 10 is assembled as follows.

As shown in FIGS. 2 to 4, first, the lens 11 is attached to the lens barrel 14.
Insert it into the inside of the
Inserted into the inside 18 from the outside, and the both guided projections 21 are attached to the outer periphery of the lens holder 20 with the both screws 22.

Next, the rotating rings 35 and 36 are slightly opened at the cutting portion 37, and the outer peripheral surface of the lens barrel 14 is fitted from the flange portion 15 side of the lens barrel 14, and the both rotating rings 35 and 36 are attached to the lens barrel. The two flange portions 15 and 16 of 14 come into contact with the facing surfaces in the optical axis direction a.

Next, the split cylinders 24 and 25 are fitted on the outer circumference of the lens barrel 14 between the rotary rings 35 and 36 from a direction perpendicular to the optical axis direction a.

At this time, as shown in FIG. 5, the divided surfaces 27 and 28 of the divided cylinders 24 and 25 are brought into contact with each other to form a pair of dowels 29 and dowel holes.
By fitting 30 with each other, both split cylinders 24,
The rotary cylinder 23 is assembled by connecting 25 in a cylindrical shape.

Then, the spiral grooves 26 of the split cylinders 24 and 25 are fitted to the tips of the guided projections 21 protruding outward of the linear grooves 18.

Further, as shown in FIG. 6, the small protrusions 39 of the rotary rings 35 and 36 are cut from both sides in the circumferential direction by the notches 40 at both ends of the split surfaces 27 and 28 of the split cylinders 24 and 25. By sandwiching them, both rotating rings 35, 36 are coupled to both divided cylinders 24, 25 so as to rotate together.

Next, the outer circumference of the two divided cylinders 24, 25 is covered with an elastic body 33 in a cylindrical shape against the elasticity, and the elastic body 33 divides the two divided cylinders 24,
Hold 25 in a cylindrical shape by lightly tightening it from the outer circumference. The elastic body 33 is positioned between the flange portions 31 and 32 of the divided cylinders 24 and 25.

Finally, the annular portion 42 of the eye cap 12 is elastically fitted from the outer periphery to the slit 19 of the lens barrel 14 by the ribs 43 to complete a series of assembling.

The diopter adjusting device 10 assembled in this manner has the two straight groove 18
The guide mechanism for the guided projections 21 is assembled by the spiral grooves 26.

Accordingly, when the rotary cylinder 23 is rotated around the outer circumference of the lens barrel 14 in the direction of arrow b in FIG. 4, both guided projections 21 are moved and adjusted along the linear grooves 18 by the feeding action of the spiral grooves 26. Then, the lens 11 is moved and adjusted integrally with the lens holder 20 in the lens barrel 14 in the optical axis direction a shown in FIG. 3, and desired diopter adjustment can be performed. At this time, both rotating rings 35, 36
Is rotated integrally with the rotating cylinder 23.

At this time, the elastic body 33 having the knurls 34 for slip prevention formed on the outer peripheral surface thereof also functions as a slip stopper for fingers when the rotary cylinder 23 is rotated.

Then, the divided cylinders 23 and 24 each having the spiral groove 26.
Since each has a semi-cylindrical shape, each of the divided cylinders 23 and 24 can be extremely easily injection-molded (or die cast) together with the spiral groove 26 by using the simplest two-division type mold. There is no need to undercut groove 26.

Further, both spiral grooves 26 are independently formed inside both split cylinders 24 and 25, and both spiral grooves 26 are divided into both split cylinders.
Since there is no joint like when formed over 24 and 25, the feeding action of both guided projections 21 by both spiral grooves 26 can be performed smoothly.

Next, the click mechanism 45 will be described with reference to FIGS. 1, 2, and 7.

That is, one end of the rotating cylinder 23 in the optical axis direction a is formed, and a part of one rotating ring 35 made of synthetic resin or the like is integrally formed with a circle so as to rotate integrally with the rotating cylinder 23. The arc-shaped elastic piece 46 and the convex portion 47 arranged on the side surface of the intermediate portion of the elastic piece 46 are integrally provided. Both ends 46a of the elastic piece 46 in the arc direction are integrally connected to the rotary ring 35, and the convex portion 47 is configured to be elastically displaceable in the optical axis direction a by the elastic bending action of the male piece 46. There is. And the convex part
47 is opposed to the side surface 15a of one flange portion 15 provided on the outer periphery of one end portion of the lens barrel 14 in the optical axis direction a from the optical axis direction a, and the convex portion 47 is elastic on the side surface 15a. A plurality of recesses 48 that are engaged with each other are provided with small pitches.

According to this click mechanism 45, as shown in FIG. 7, when the rotary cylinder 23 is rotationally adjusted in the direction of the arrow b to perform the desired diopter adjustment, the convex portion 47 is a concave portion as indicated by the one-dot chain line. While climbing from 48 to the side surface 15a against the elasticity of the elastic piece 46,
As shown by the solid line, the convex portion 47 sequentially engages with the concave portion 48 by the elastic repulsive force of the elastic piece 46, and the rotary cylinder 23 is sequentially positioned by the small pitch. Therefore, since the rotation cylinder 23 is sequentially positioned by the engagement of the convex portion 47 and the concave portion 48 at the position where the rotation is stopped, the adjusted diopter is unlikely to be distorted.

It should be noted that the click mechanism 45 is provided with the other rotation ring 36 and the lens barrel 14 which constitute the other end of the rotation cylinder 23 in the optical axis direction a.
Similarly, it is also provided between the other flange portion 16 and the recessed portion 48 of the click mechanism 45 on both sides of the rotary cylinder 23.
The rotating cylinder 23 is recessed 4 so that the 1/2 pitches are displaced from each other.
It can also be configured so that it is sequentially positioned with 8 1/2 pitches.

Further, the elastic piece 46 and the convex portion 47 are directly provided on the end portion of the rotary cylinder 23 in the optical axis direction a, or the elastic piece 46 and the convex portion 47 are directly provided on the flange portion 15 or 16 of the lens barrel 14 and the rotary cylinder 23. If a plurality of recesses 48 are provided at the end in the optical axis direction a, both rotating rings 35 become unnecessary. Therefore, the elastic piece 46 and the convex portion
47 and the plurality of recesses 48 are the end side of the rotating cylinder 23 and the lens barrel.
It may be arranged on either side of the flange portion 15 or 16 of 14.

The embodiments of the present invention have been described above, but the present invention is not limited to the above embodiments, and various effective modifications can be made based on the technical idea of the present invention.

[Advantages of the Invention] Since the present invention is configured as described above, it has the following effects.

Since the rotating cylinder having the spiral groove is divided into a plurality of parts in the circumferential direction, the rotating cylinder can be extremely easily processed by injection molding or the like. Since the rotary cylinder can be assembled very simply by fitting the plurality of divided cylinders to the outside of the lens barrel and then covering the outer circumference thereof with the cylindrical elastic body, the workability of the assembly is high. Therefore, it is possible to improve the productivity and reduce the cost, and it is most suitable as a viewfinder for the value-added model.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention. FIG. 1 is an exploded perspective view of a diopter adjusting device, FIG. 2 is a side view of the diopter adjusting device in an assembled state, and FIG. 2 is a sectional view taken along the line III-III in FIG. 4, FIG. 4 is a sectional view taken along the line IV-IV in FIG. 2, FIG. 5 is an enlarged sectional view showing the connecting structure of divided cylinders, and FIG. FIG. 7 is an enlarged cross-sectional view showing the coupling structure of the split cylinder and the rotary ring, FIG. 7 is an enlarged side view showing the click mechanism, and FIG. 8 is a perspective view of the entire portable video camera. In the reference numerals used in the drawings, 5 ... viewfinder 10 ... diopter adjustment device 11 ... lens 14 ... lens barrel 18 ... straight groove 21 ... guided projection 23 ... rotating cylinder 24,25 …… Split cylinder 26 …… Lens groove 33 …… Elastic body a …… In the optical axis direction.

Claims (1)

[Scope of utility model registration request] 1. A lens barrel, a diopter adjusting lens arranged inside the lens barrel, a rotary cylinder rotatably arranged outside the lens barrel, and a spiral shape provided on the rotary cylinder. The guide groove provided on the outer circumference of the lens is guided by the spiral groove and the straight groove provided on the lens barrel in parallel with the optical axis direction, and the lens is optically guided by the rotation of the rotary cylinder. A guide mechanism for moving and adjusting in the axial direction is provided, and the rotating cylinder is composed of a plurality of divided cylinders that are divided in the circumferential direction, and the plurality of divided cylinders are held in a cylindrical shape from the outer periphery by a cylindrical elastic body. A viewfinder diopter adjustment device characterized in that