JPH06300950A - Structure for lens spacing ring for lens barrel - Google Patents

Abstract

PURPOSE:To reduce the number of parts and the assembly man-hour of a lens barrel by forming an acute projected line part on the inner peripheral surface of a lens spacing ring keeping space between the lenses in the lens barrel specified space and using the projected line part also as a light shielding plate for preventing flare. CONSTITUTION:Plural lenses 18 are arranged in order along an optical axis 20 in the lens barrel 16, and the lenses 18 are kept by the lens spacing ring 22 so that the space between the lenses 18 may be the specified one. The projected line part 22A whose cross section is triangular is formed on the inner peripheral surface of the ring 22. In order to use the ring 22 also as the light shielding plate for preventing the flare, the ring 22 is formed so that the inside diameter L of the projected ring part 22A may be equal to the inside diameter L of the light shielding plate in size. Namely, the projected line part 22A of the ring 22 is used also as the light shielding plate for preventing the flare.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens spacing ring structure for a lens barrel, and more particularly to a lens spacing ring structure for a lens barrel disposed at a distal end hard portion of an endoscope insertion portion.

[0002]

2. Description of the Related Art As shown in FIG. 3, a plurality of lenses 2, 2, ... Are arranged in order on a lens barrel 1 provided at a distal end hard portion of an endoscope insertion portion. Two
Are held by the lens spacing rings 3 and 3 such that the spacing between the lenses 2, 2 is a predetermined spacing.

In the lens barrel 1, the lenses 2,
The peripheral portions of 2 ... Are black-processed, or the light-shielding plate 4 of a thin piece is arranged between the lens spacing ring 3 and the lens spacing ring 3,
I try not to create flare.

[0004]

However, in the conventional lens barrel, the plurality of light-shielding plates 4 must be provided in the lens barrel 1, which has a disadvantage of increasing the number of parts. Further, in the conventional lens barrel, the lenses 2 and 2 are
... Two lens spacing rings 3 and 3 and one light shield plate 4 for each interval
Therefore, there is a drawback that the number of assembling steps of the lens barrel 1 is also increased.

Further, in the conventional lens barrel, when the diameter of the endoscope insertion portion becomes small, that is, when the diameter of the lens barrel 1 becomes small, the lens spacing ring 3 and the light shielding plate 4 also become small in diameter and thin. Therefore, there is also a drawback that it becomes difficult to control the dimensions of the lens spacing ring 3 and the light shielding plate 4. The present invention has been made in view of the above circumstances, and an object thereof is to provide a lens-interval ring structure for a lens barrel that can reduce the number of parts and the number of assembling steps.

[0006]

In order to achieve the above object, the present invention maintains a predetermined distance between a plurality of lenses in a lens barrel by a lens spacing ring which is separate from the lens barrel. In the above described lens barrel, a sharp projection is formed on the inner peripheral surface of the lens spacing ring to prevent flare.

[0007]

According to the present invention, a sharp ridge is formed on the inner peripheral surface of the lens spacing ring, and this ridge is also used as a light-shielding plate for flare prevention. Thus, according to the present invention, the number of parts can be reduced and the number of assembling steps can be reduced as compared with the conventional lens spacing ring structure of the lens barrel in which the light blocking plate is provided between the lens spacing rings. it can.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the lens spacing ring structure of the lens barrel according to the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a sectional view showing a first embodiment of a lens-interval ring structure of a lens barrel according to the present invention, which is provided in a hard end portion of an endoscope.

As shown in FIG. 1, an objective lens 12 and a diaphragm 14 are provided in a distal end hard portion 10 of an endoscope insertion portion, and a cylindrical lens barrel 16 is arranged behind the diaphragm 14. To be done. The lens barrel 16 includes a plurality of lenses 1
, 18 are sequentially arranged along the optical axis 20, and these lenses 18, 18 ... Include lens spacing rings 22, 22.
Are held so that the distance between the lenses 18, 18 ... Is a predetermined distance.

The lens spacing ring 22 is provided with a ridge 22A having a triangular cross section on its inner peripheral surface. The lens spacing ring 22 is formed such that the inner diameter L of the protruding portion 22A is equal to the inner diameter L of the light shielding plate 4 so that the light shielding plate 4 shown in FIG. That is, in the lens spacing ring structure of the lens barrel of the present embodiment, the protruding portion 22A of the lens spacing ring 22 is also used as the light blocking plate 4 for flare prevention.

Thus, according to this embodiment, the light shield plate 4 is provided between the lens spacing ring 3 (see FIG. 3) and the lens spacing ring 3.
In comparison with the conventional lens spacing ring structure of the lens barrel, the light shielding plate 4 is unnecessary, and the lens spacing ring 22 arranged between the lenses 2 and 2 can be reduced from two to one. The width dimension can be designed to be more than double. Therefore, in this embodiment, the number of parts of the lens barrel 16 can be reduced, and the number of assembling steps can be reduced.

FIG. 2 is a sectional view showing a second embodiment of the lens spacing ring structure of the lens barrel according to the present invention. This second
In the lens spacing ring 30 applied to the embodiment, the convex portion 32 is formed along the inner peripheral surface thereof, and the tip portion 32A of the convex portion 32 is formed in a knife edge shape. Thus, even if the inner peripheral surface of the lens spacing ring 30 is formed, flare can be prevented.

In this embodiment, the lens barrel 16 provided at the distal end hard portion of the endoscope insertion portion has been described.
The present invention is not limited to this, and can also be applied to a lens barrel provided in a camera-integrated VTR.

[0014]

As described above, according to the lens spacing ring structure of the lens barrel of the present invention, a sharp ridge is formed on the inner peripheral surface of the lens spacing ring, and the ridge is flared. Since it is also used as a light blocking plate for prevention, the number of parts can be reduced and the number of assembly steps can be reduced as compared with the conventional lens spacing ring structure of the lens barrel in which the light blocking plate is provided between the lens spacing rings. Can be reduced.

In particular, an endoscope such as an endoscope having a small inner diameter of the lens barrel is advantageous in processing parts and assembling parts.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of a lens spacing ring structure of a lens barrel according to the present invention.

FIG. 2 is a sectional view showing a second embodiment of the lens spacing ring structure of the lens barrel according to the present invention.

FIG. 3 is a cross-sectional view showing an example of a conventional lens spacing ring structure of a lens barrel.

[Explanation of symbols]

 16 ... Lens barrel 18 ... Lens 20 ... Optical axis 22, 30 ... Lens spacing ring 22A ... Ridge portion 32 ... Convex portion

Claims (1)

[Claims] 1. A lens barrel in which a distance between a plurality of lenses in the lens barrel is maintained at a predetermined distance by a lens spacing ring which is separate from the lens barrel, and an inner circumference of the lens spacing ring is provided. A lens spacing ring structure of a lens barrel, characterized in that a sharp ridge is formed on the surface to prevent flare.