JPH10293235A - Lens barrel and optical equipment provided therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the vignetting of an optical path caused by the positional deviation of a mask by providing on at least one of plural lenses with a positioning means for positioning a mask member in an optical axis direction. SOLUTION: Projections (position regulating means) 2a projecting in the optical axis direction are formed at three points (at equal intervals) in the peripheral direction of a photographing lens 2. An aperture part 4a for securing a photographing optical path is formed in the center part of the mask 4 covering over the plane part 3a of the photographing lens 3. The mask 4 is arranged between the lenses 2 and 3 and interposed between three projections 2a of the lens 2 and the plane part 3a of the lens 3 so as to be positioned in the optical axis direction. Therefore, even when the lens barrel is vibrated, the mask 4 is surely prevented from being deviated in the optical axis direction, getting into the chamfered part of the abutting part of the lens 3 or causing the vignetting.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens barrel having a plastic lens, and an optical apparatus such as a camera provided with the lens barrel.

[0002]

2. Description of the Related Art When a plastic lens is used as a lens in a lens barrel, a flat portion is generally provided outside the effective diameter of the lens in order to assure the accuracy of the lens surface and to receive a lens holder. It is. As shown in FIG. 5A, a lens 12 and a lens 1 each having a flat portion are provided for the purpose of improving the appearance of the flat portion from the front.
There is a case where the mask 13 is arranged between the first and second masks.

Further, in order to guarantee the distance between the lenses 11 and 12, it is common to directly contact the lenses 11 and 12 with each other. It is often the case that a contact portion is provided and these contact portions are brought into contact with each other. Then, in this case, the mask 13
Is disposed in a gap portion inside the contact portion.

[0004]

However, the dimension of the gap portion where the mask 13 is arranged in the optical axis direction is smaller than that of the mask 1.
If the thickness is larger than the thickness of 3, the mask 13 moves in the optical axis direction in the gap due to vibrations and the like received by the lens barrel. Moreover, if the edge of the contact portion is chamfered as shown in, for example, part A of FIG. 5B, the mask 13 may enter this chamfered portion and shift in a direction perpendicular to the optical axis. Then, in this case, the mask 13 is
5B, there is a problem that vignetting occurs as shown in part B of FIG. 5B.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a lens barrel capable of preventing optical path vignetting due to a mask displacement, and an optical apparatus having the same.

[0006]

In order to achieve the above object, according to the present invention, in a lens barrel in which a mask member is disposed between a plurality of lenses, at least one of the plurality of lenses includes: Positioning means for positioning the mask member in the optical axis direction is provided.

More specifically, when a plurality of lenses are disposed in contact with each other in the optical axis direction, a projection or a ridge is positioned radially inward from the contact portion of each lens as the positioning means. It is provided.

In the present invention, the mask member itself is provided with positioning means (projections and ridges) for positioning the mask member in the optical axis direction.

According to such a configuration, the mask member can be reliably positioned in the optical axis direction, and the displacement of the mask member in the optical axis direction or the direction orthogonal to the optical axis can be prevented. Become.

In the present invention, by providing such a lens barrel, it is possible to provide an optical device such as a camera capable of taking a picture without vignetting by a mask member.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) FIGS. 1 and 2 show a lens barrel according to a first embodiment of the present invention. This lens barrel is used by being attached to an optical device such as a still camera or a video camera.

In these figures, 1, 2 and 3 are photographing lenses (plastic lenses). These photographing lenses 1, 2, and 3 are arranged in a state where the contact portions provided on the outer peripheral portion thereof are in contact with each other, whereby a predetermined distance between the lenses is guaranteed. Also, the circumferential direction 3 of the photographing lens 2
Projections (position regulating means) 2a protruding in the optical axis direction are formed at the positions (three positions at equal intervals).

Reference numeral 4 denotes a mask for covering the flat portion 3a of the taking lens 3. An opening 4a for securing a photographing optical path is formed in the center of the mask 4. This mask 4
It is arranged between the taking lens 2 and the taking lens 3,
The positioning in the optical axis direction is performed by being sandwiched between the three projections 2 a of the photographing lens 2 and the flat portion 3 a of the photographing lens 3.

For this reason, according to the present embodiment, even when vibrations or the like are applied to the lens barrel, the mask 4 is displaced in the optical axis direction, or enters the chamfered portion of the contact portion of the photographing lens 3 to cause vignetting. Can be reliably prevented.

Reference numeral 5 denotes a lens holder for holding the photographing lenses 1, 2, 3, and the mask 4, and a lens cap 6
It is fixed by.

In this embodiment, the case where the projection lens is provided with three projections has been described. However, the number of projections in the present invention is not limited to three.

(Second Embodiment) FIG. 3 shows a second embodiment of the present invention.
1 shows a taking lens used for a lens barrel according to an embodiment. This photographic lens 2 'is used in place of the photographic lens 2 of the first embodiment.

Inside the abutting portion of the taking lens 2 ', there is formed a ridge 2a' projecting in the optical axis direction and extending over the entire circumference.

In the present embodiment, similarly to the first embodiment, the mask 4 is positioned in the optical axis direction by being sandwiched between the ridge 2a 'of the taking lens 2' and the flat portion 3a of the taking lens 3. 4 can be reliably prevented.

(Third Embodiment) FIG. 4 shows a third embodiment of the present invention.
2 illustrates a mask and a photographing lens used in a lens barrel according to an embodiment. The mask 4 'is used in place of the mask 4 of the first embodiment, and the taking lens 3 is the same as that of the first embodiment.

Protrusions (position regulating means) 4 protruding in the optical axis direction are provided at three places in the circumferential direction (three places at equal intervals) of the mask 4 '.
b 'is formed. The mask 4 ′ is positioned in the optical axis direction by bringing its three projections 4 b ′ into contact with the flat part of the taking lens 2 and making the rear face contact with the flat part 3 a of the taking lens 3. You.

Therefore, also in the present embodiment, the displacement of the mask 4 'can be reliably prevented, as in the first embodiment.

In this embodiment, the case where three projections are provided on the taking lens has been described, but the number of projections in the present invention is not limited to three.

In this embodiment, the case where the projection is provided on the mask has been described. However, instead of the projection, a projection as described in the second embodiment may be formed on the mask.

[0025]

As described above, according to the present invention,
Since the mask member can be reliably positioned in the optical axis direction, the displacement of the mask member in the optical axis direction or the direction orthogonal to the optical axis and the occurrence of vignetting due to the displacement can be prevented.

By providing such a lens barrel, it is possible to provide an optical device such as a camera capable of taking a picture without vignetting by a mask member.

[Brief description of the drawings]

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

FIG. 2 is a perspective view of a lens and a mask used in the lens barrel.

FIG. 3 is a perspective view of a lens used for a lens barrel according to a second embodiment of the present invention.

FIG. 4 is a perspective view of a lens and a mask used in a lens barrel according to a third embodiment of the present invention.

FIG. 5 is a sectional view of a conventional lens barrel.

[Explanation of symbols]

 1, 2, 2'3 Shooting lens 2a, 4b 'Projection 2a' Ridge 4 4 'Mask 5 Lens holder 6 Lens cap

Claims (8)

[Claims] 1. A lens barrel in which a mask member is arranged between a plurality of lenses, wherein at least one of the plurality of lenses is provided with positioning means for positioning the mask member in the optical axis direction. Characteristic lens barrel. 2. The method according to claim 1, wherein the plurality of lenses are disposed in contact with each other in an optical axis direction, and the positioning means is provided radially inward of a contact portion of each of the lenses. The lens barrel according to claim 1. 3. The lens barrel according to claim 1, wherein said positioning means is a projection formed at a plurality of positions in a circumferential direction of said lens. 4. The lens barrel according to claim 1, wherein the positioning means is a ridge formed over the entire circumference of the lens. 5. A lens barrel in which a mask member is disposed between a plurality of lenses, wherein said mask member is provided with positioning means for positioning the mask member in the optical axis direction. 6. The lens barrel according to claim 5, wherein said positioning means is a projection formed at a plurality of positions in a circumferential direction of said mask member. 7. The lens barrel according to claim 5, wherein the positioning means is a ridge formed over the entire circumference of the mask member. 8. An optical apparatus comprising the lens barrel according to claim 1.