JPH0736330Y2 - Lens holding device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a lens holding device that can be used as a taking lens for a video camera or the like.

2. Description of the Related Art In recent years, with the spread of video cameras, the demand for taking lenses has rapidly expanded, and the use of Jusi and the like has increased the demand for smaller size, lighter weight, and lower cost. Even in a lens barrel that holds a lens, attempts have been made to improve productivity by simplifying the configuration.

A conventional lens holding device will be described below with reference to the drawings.

FIG. 5 is a partial cross-sectional view of a conventional lens holding device, showing a structure often used for fixing a master lens group for adjusting a back focus (hereinafter referred to as BF) of a zoom lens. In FIG. 5, 1 is an optical axis, 2 and 3
Are two split lens barrels of the same shape which are split into two in a plane including the optical axis 1. The split lens barrels 2 and 3 are made of a resin material, and the lenses 4,5, 6, 7, 8 can be inserted in a direction perpendicular to the optical axis 1. To describe the holding with one lens, the outer peripheral portion of the lens 8 is positioned by the lens holding portion 9 on the inner surface of the split lens barrel 2, and
The lens 8 is pressed against the lens restricting portion 11 by the elastic piece 10 provided inside the lens to position the lens in the optical axis direction. The other lenses 4, 5, 6 and 7 are also held in the same manner. After inserting the lens into one of the split lens barrels 2, the other split lens barrel 3 is covered and the outer circumferences of the split lens barrels 2 and 3, for example, are known. Adhesive tape 1
While winding 2 and inserting a ring-shaped BF gear 13 from the direction of the optical axis, the split lens barrels 2 and 3 are in close contact with each other. The connection between the split lens barrels 2 and 3 and the BF gear 13 is shown in FIG. Recesses 16 provided inside the BF gear 13 on convex portions 14 and 15 provided on the insertion portion of the BF gear 13 at the divided portions of the split lens barrels 2 and 3.
Engage with each other, and the BF gear 13 and the split lens barrels 2 and 3 are integrated. Returning to FIG. 5, 17 is an outer frame, and 18 is a female screw provided on the inner side of the outer frame 17, which is screwed with the male screw 19 of the split lens barrels 2 and 3. Reference numerals 20 and 21 are guide portions, and the split lens barrels 2 and 3 are movable with respect to the outer frame 17 in the optical axis 1 direction. Reference numeral 22 denotes a coil spring, which biases the split lens barrels 2 and 3 via the BF gear 13 against the outer frame 17 in the optical axis 1 direction. Further, there is no problem with the known means replacing the coil spring. Reference numeral 23 is a hole provided in the outer frame 17 so that the BF gear 13 can be driven from the outside.

However, in the conventional configuration, since the split lens barrels 2 and 3 are made of a resin material and have a half-divided structure, shrink marks in the direction of arrow A as shown in FIG. Cause Therefore, the contact surface is formed in the central portion, and the dimensions of the guide portions 20 'and 21' provided on both sides thereof are not stable, making it difficult to insert the BF gear 13 or inserting it into the outer frame 17 by the guide. Department
A code is generated at 20 and 21, and the outer frame 17 of the split lens barrels 2 and 3
The load of rotating and inserting the lens into the lens barrel fluctuates greatly, which hinders the work, or causes the split lens barrels 2 and 3 to be misaligned with each other. Further, it is not possible to effectively form the optical effective diameter of the light flux in the vicinity of the lenses 4 and 8, and the gap Δl of the mating surfaces of the split lens barrels 2 and 3 causes the leakage light to be mixed in due to reflection and the like, and ghost flare is generated. It was a factor. Further split lens barrel 2
The holding of the lenses 4 to 8 in the lens Nos. 3 and 3 is incomplete due to the warp A, which also causes deterioration of the optical performance.

The present invention has been made in view of the above problems, and an object thereof is to provide a lens holding device capable of improving the workability of a lens barrel and the optical performance thereof.

In order to achieve the above object, the lens holding device of the present invention is
A plurality of lenses and a holding groove for holding the lens are provided on the inner surface, and the lens is divided into two parts by a plane including the optical axis of the lens, and their mating contact surfaces are provided near both ends thereof. A split lens barrel and a BF that can be fitted to the outer periphery of the split lens barrel
The split mirror having a gear, positioning means for positioning the BF gear with respect to the split lens barrel, a male screw provided on an outer peripheral portion of the split lens barrel, and a female screw screwed to the male screw. An outer frame for holding the barrel and a biasing means for biasing the split lens barrel in the optical axis direction with respect to the outer frame are provided.

Operation The present invention makes it possible to improve workability and optical performance by arranging the abutting surfaces of the above-mentioned split lens barrels in the vicinity of both ends thereof.

Embodiment Hereinafter, a lens holding device according to an embodiment of the present invention will be described with reference to the drawings. 1 to 4 show a lens holding device according to an embodiment of the present invention. Description of common drawing numbers will be omitted, and new ones will be described. In FIG. 3, reference numerals 24 and 25 are mating contact surfaces provided near the lenses 4 and 8 located at both ends of the split lens barrels 2 and 3 and on the inner diameter side thereof. A step of about 0.05 to 0.2 mm is provided in advance between the mating contact surfaces 24 and 25 and the other mating surface 26 in consideration of shrinkage shrinkage of the material, and the split lens barrels 2 and 3 are integrated and integrated. In the above, as shown in FIG.
25 are adapted to fit together. 26 is the aforementioned BF gear
An external gear for driving 13 is shown, which is used when the master lens is moved in the direction of the optical axis 1 to adjust the BF.

The operation of the lens holding device configured as described above will be described below.

The split lens barrels 2 and 3 holding the lenses 4, 5, 6, 7, 8 and having the BF gear 13 inserted therein are assembled in a state of being screwed to the outer frame 17 via the coil spring 22. When adjusting the BF of the camera unit (not shown), use the gear 26 through the hole 23 provided in the outer frame 17 to adjust the BF.
When the gear 13 is driven, the split lens barrels 2 and 3 are moved relative to the outer frame 17 in the optical axis 1 direction. At this time, since the urging force of the coil spring 22 acts, the split lens barrels 2 and 3 are immovably fixed to the outer frame 17 by the frictional force between the male screw 19 and the female screw 18, so that the adjustment is possible. BF adjustment does not go wrong even if you take off gear 26 of. The mating contact surfaces 24 and 25 of the split lens barrels 2 and 3 ensure that the corresponding surfaces are matched.

As described above, according to this embodiment, lens assembly and BF adjustment are facilitated, workability is improved, and the mating contact surfaces 24 and 25 are adjusted.
Since it comes into contact with the establishment, the effective diameter of light can be reliably formed,
It can cut off excess reflected light.

EFFECTS OF THE INVENTION According to the present invention, a plurality of lenses and a holding groove for holding the lenses are provided on the inner surface, and the lens is divided into two parts by a plane including the optical axis of the lenses. A split lens barrel provided near both ends thereof, a BF gear that can be fitted to the outer peripheral portion of the split lens barrel, positioning means for positioning the BF gear with respect to the split lens barrel, and the split lens barrel A male screw provided on an outer peripheral portion, an outer frame having a female screw threaded to the male screw and holding the split lens barrel, and the split lens barrel urged in the optical axis direction with respect to the outer frame. By providing the urging means to stabilize the size of each part of the split lens barrel and improve the assembling workability, there is little stress on the split lens barrel and the deterioration of the performance can be prevented. By joining, the light flux can be reliably cut with an effective diameter Provides positive cutting reflected light coming, in which is excellent effect that it is possible to suppress the occurrence of ghost flare is obtained.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of a lens holding device according to an embodiment of the present invention, and FIG. 2 is a partial sectional view of a BF gear portion, FIG.
FIG. 4 is an explanatory view of the split lens barrel portion, FIG. 5 is a sectional view of a conventional lens holding device, and FIG. 6 is an explanatory view of the split lens barrel portion. 2,3 …… Split barrel, 4,5,6,7,8 …… Lens, 9 …… Lens holding part, 10 …… Elastic piece, 11 …… Lens control part, 13 …… BF
Gear, 17 ... Outer frame, 18 ... Female screw, 19 ... Male screw, 20,2
1 …… Guide part, 22 …… Coil spring, 24,25 …… Mating contact surface.

Claims (1)

[Scope of utility model registration request] 1. A plurality of lenses, a holding groove, a male screw for position adjustment, and a positioning means for a back focus gear, which are provided inside the lens to hold the lenses,
It has a split lens barrel divided into two parts on a plane including the optical axis of the lens, a back focus gear fitted to an outer peripheral portion of the split lens barrel, and a female screw screwed with a male screw of the split lens barrel. An outer frame that holds the split lens barrel, and a biasing unit that biases the split lens barrel in the optical axis direction with respect to the outer frame,
A lens holding device, characterized in that the mating abutting surfaces of the split lens barrels are provided in the vicinity of and inside the lens holding grooves located at both ends thereof.