JPS6315848Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lens holding barrel for use in cameras and the like, which has a screw hole in the optical axis direction near the lens.

Conventionally, in this type of lens holding barrel, other members such as a lens holding ring, distance ring, intermediate ring, etc. are fixed using screw holes provided in the optical axis direction near the lens. Deformation of the lens holding barrel due to screw fixation, especially deformation of the lens fitting part, makes it difficult to accurately align the optical axis of the lens being held. There was a problem in that it was not possible to securely fix even parts with high accuracy.

FIGS. 1 and 2 show conventional methods for resolving such problems. Figure 1a shows the lens holding barrel 2 that holds the lens 1.
1 shows a conventional mechanism in which a lens holding ring 3 is fixed with a locking screw 4, and FIG. 1b shows a cross section B-B in FIG. In FIGS. 1a and 1b, when the set screw 4 is strongly tightened, the lens holding barrel 2 is partially deformed, for example, a convex portion 2 is formed on a part of the lens fitting portion 2a.
b is generated and causes the optical axis of the lens 1 to be misaligned.

In addition, the mechanism shown in FIG. 2 is one of the conventional examples proposed to improve the above-mentioned drawbacks, and
Figure a is a sectional view, and figure b is a front view of main parts. In this case, the lens holding barrel 12 that holds the lens 11 is molded from synthetic resin, and the lens fitting portion 12 of the self-tapping screw hole 15 is molded in the optical axis direction.
A large diameter portion 15a having a diameter larger than the thread diameter of the self-tap screw is provided in a portion corresponding to a, that is, in the range of ₁ of a. Therefore, the self-tap screws for fixing the coupling members (not shown) are
Since it will engage only with the small diameter part 15b in the range ₂ excluding the large diameter part 15a, the lens fitting part 12
Although no deformation occurs in a, there is a drawback that the engagement length of the screws becomes shorter and the bonding strength becomes weaker. In particular, when there is _a limit to the space in the optical axis direction,
If a is used to prevent deformation of the lens fitting portion 12a, the engagement length of the screws will be considerably restricted, resulting in a significant decrease in bonding strength.

The main purpose of this invention is to improve the above-mentioned conventional drawbacks, and to firmly fix the member connected to the lens holding barrel with a set screw in the optical axis direction without causing deformation of the lens fitting part. The purpose is to provide a lens holding lens barrel which is integrally molded of synthetic resin and has a screw hole for self-tapping in the optical axis direction near the lens, and which has a screw hole for self-tapping in the optical axis direction. The hole forms a small diameter part having a normal screw hole diameter except for the length range in the optical axis direction corresponding to the lens fitting part of the lens holding barrel, and has a length corresponding to the lens fitting part. In the above range, the lens is characterized in that the lens has an oval hole having a major axis approximately equal to the thread diameter of the screw in the diameter direction and a minor axis approximately equal to the diameter of the small diameter portion in the circumferential direction. .

Next, the present invention will be explained in detail based on the embodiments shown in FIG. 3 and below.

FIG. 3 shows an embodiment of the lens holding barrel according to the present invention, in which a is a sectional view and b is a front view of the main part.
The lens holding barrel 22 that holds the lens 21 is integrally molded of synthetic resin with a self-tap screw hole 25 in the optical axis direction.
The range ₂ excluding the range ₁ corresponding to the lens fitting part 22a is a small diameter part 25b having a normal screw hole diameter. Lens fitting part 22
The large diameter portion 25a in the range ₁ corresponding to a is an oblong hole having a major axis E in the diametrical direction of the lens 21 and a minor axis D in the circumferential direction of the lens 21. Here, the short axis D is equal to the diameter of the small diameter portion 25b, and the long axis E is approximately the same size as the thread diameter of the self-tap screw.

Therefore, when the lens holding ring 23 is connected to the lens holding barrel 22 with the self-tap screw 24 as shown in FIGS. The lens has a major axis E in the diametrical direction of the lens in a range of ₁ corresponding to 22a, and since this is almost the same as the thread diameter of the self-tap screw 24, the screw 24 will not get caught. Further, since the short diameter D of the lens 21 in the circumferential direction is the same as the size of the stop hole of the self-tap screw 24, the self-tap screw 24
are engaged in the direction of the short axis D of the large diameter portion 25a. In other words, the self-tap screw 24 engages with the normal self-tap screw 24 in the range ₂ , and in the range ₁ , it moves in a direction that does not deform the lens fitting part 22a, that is, in the circumferential direction shown in FIG. 4b. The second
Compared to the conventional case where it is only within the range of ₂ as shown in the figure, it is possible to make the engagement length of the screw sufficiently large.

In the embodiment, the lens holding ring 23 is shown as an example of the coupling member, but other members for other uses such as distance rings and intermediate rings can be similarly coupled.

As described above, according to the lens holding barrel according to the present invention, the range corresponding to the lens fitting part of the screw hole is made into an oval hole, and the major axis of the hole is made to coincide with the major axis direction of the lens. Even when the screw is screwed in and tightened, the optical axis of the lens can be easily and accurately matched without causing any deformation in the lens fitting part that would disturb the axis of the lens. Furthermore,
Since the engagement length of the screws can be made sufficiently larger than in the conventional method as shown in FIG. 2, it is possible to securely and precisely fix the coupling member.

[Brief explanation of the drawing]

FIG. 1 shows a conventional lens holding barrel, a is a sectional view, b is a sectional view taken along line B-B of a, FIG. 2 is an improved conventional lens holding barrel, a is a sectional view,
b is a front view of the main part, Fig. 3 and the following shows an embodiment of the lens holding barrel according to the present invention, a is a sectional view, b is a front view of the main part, and Fig. 4 a is a lens holding ring. A cross-sectional view of the combined state, and b is a cross-sectional view taken along the line B-B of a. Reference numeral 21 is a lens, 22 is a lens holding barrel, 2
2a is a lens fitting part, 23 is a lens holding ring,
24 is a self-tap screw, 25 is a screw hole,
25a is a large diameter portion, and 25b is a small diameter portion.

Claims (1)

[Scope of utility model registration request] A lens holding lens barrel integrally molded from synthetic resin and having a screw hole for self-tapping in the optical axis direction near the lens, the screw hole corresponding to a lens fitting part of the lens holding lens barrel. Outside the length range in the optical axis direction, a small diameter part is formed with a normal screw hole diameter, and in the length range corresponding to the lens fitting part, the diameter direction of the lens is approximately the same as the thread diameter of the screw. A lens-holding lens barrel characterized in that the hole has an oval shape with equal long diameters and a short diameter in the circumferential direction equal to the diameter of the small diameter portion.