JPH10268383A - Lens cap for camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the cost and the assembly man-hour of a lens cap by forming the lens cap integrally with a part of members constituting a photographing lens unit so that it can be ruptured. SOLUTION: The photographing lens unit 12 is provided with a front group lens 14 forward and a rear group lens 16 backward with reference to an optical axis L. The lens cap 10 is attached to the front of the lens 14. The lens cap 10 is formed of transparent plastic material by injection molding so that it may be integrated with a lens pressing ring (lens pressing member) 36 for positioning the lens 14 with reference to a lens barrel 20. A V-shaped groove 40 is formed in the circumferential direction at a coupling part between the lens cap 10 and the ring 36, and it is ruptured by external force, so that the lens cap 10 is ruptured from the ring 36. Therefore, a mold only for a lens cap need not be formed, the number of parts is reduced and the cost and the assembly man-hour of the lens cap 10 are reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens cap for a camera, and more particularly to a lens cap for a photographing lens unit mounted on a small camera such as a monitoring camera or a vehicle-mounted camera.

[0002]

2. Description of the Related Art Conventionally, when attaching a photographic lens unit to a camera, such a lens cap is removed from the photographic lens unit and discarded without being reused.

[0003]

However, the conventional lens cap is required to manufacture the lens cap.
There is a drawback that a mold cost is required because a mold for a single lens cap must be made. In addition, it is conceivable to purchase this lens cap from another company, but in this case, there is a disadvantage that component inventory management is required. In addition, since the lens cap is a single piece, the number of parts is increased, thereby increasing parts cost and assembling man-hours.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a lens cap for a camera that can reduce cost and the number of assembly steps.

[0005]

In order to achieve the above object, the present invention provides a photographing lens unit having a photographing lens held in a lens barrel, wherein a lens cap for protecting the photographing lens is provided. The photographic lens is formed integrally with a part of the constituent members and is formed so as to be rupturable with respect to the member, and the photographic lens is exposed to the outside by breaking the lens cap from the member, and the member is a photographic lens unit. And a part of the remaining photographing lens unit.

According to the present invention, since the lens cap is formed integrally with some members constituting the taking lens unit, there is no need to make a mold for a single lens cap.
The number of parts is also reduced. As a result, the present invention can reduce the cost and the number of assembly steps required for the lens cap. On the other hand, since the lens cap is detachably formed on the member, when the photographing lens unit is used by attaching to the camera, it may be removed from the member.

According to a second aspect of the present invention, the lens cap and the lens cap which position the taking lens with respect to the lens barrel are integrally formed. By being formed integrally with a simple ring-shaped lens holding member, it can be manufactured with an inexpensive mold. According to a third aspect of the present invention, the lens cap is formed of a transparent member. Thus, according to the present invention, it is possible to carry out the optical performance inspection performed before shipping the photographing lens unit, with the lens cap attached.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a camera lens cap according to the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a sectional view of a taking lens unit 12 to which a lens cap 10 according to an embodiment of the present invention is applied. The photographing lens unit 12 shown in FIG. 1 includes a front lens unit 14 in front of the optical axis L and a rear lens unit 1 in back.
6 are provided. The front lens group 14 is held by a lens frame 18, and the lens frame 18 is fixed to a front end of a lens barrel 20. The rear lens group 16 is also held by the lens frame 22, and the lens frame 22 is fixed inside the lens barrel 20.

An iris unit 24 is provided between the front group lens 14 and the rear group lens 16. The iris unit 24 has an iris ring 26 operable from outside the lens barrel 20, and a donut-shaped chrysanthemum seat 28 is fixed inside the iris ring 26. A plurality of guide holes (not shown) are formed on the surface of the
Are connected to each other via a dowel pin (shown by a broken line in the figure) 30 which is formed radially around the center and is engaged with these guide holes. Iris ring 2
When the chrysanthemum 28 is rotated at 6, the diaphragm blades 32 move forward and backward along the guide holes of the chrysanthemum 28 in a direction approaching and away from the optical axis L. The aperture is adjusted by this operation,
When the aperture is set, the rotation of the iris ring 26 is restricted by the limit screw 34.

The lens cap 10 according to the present embodiment is mounted in front of the front lens group 14. The lens cap 10 is formed by injection molding of a transparent plastic material integrally with a lens pressing ring (lens pressing member) 36 for positioning the front group lens 14 with respect to the lens barrel 20. 2 is a front view of the lens cap 10, FIG. 3 is a cross-sectional view of the lens cap 10 taken along line 3-3 in FIG. 2, and FIG. 4 is a cross-sectional view taken along line 4-4 in FIG.

As shown in FIGS. 3 and 4, a V-shaped groove 4 is formed at a connecting portion between the lens cap 10 and the holding ring 36. As shown in FIG.
0 is formed in the circumferential direction, and the groove 40 is broken by an external force, so that the lens cap 10
It can be broken from 6. In addition, the lens cap 1
If 0 can be broken, a perforation may be formed instead of the groove 40.

2 and 3, a lens cap 10 is provided.
A protrusion 42 is integrally formed on the outer peripheral portion of the. This projection 42
Is formed so as to project in a direction perpendicular to the surface of the lens cap 10 and allows the user to pinch the lens cap 10 with his / her finger and does not break off the lens cap 10 when pulled (guaranteed strength). )).

The projection 42 is formed with a slight gap 44 with respect to the press ring 36. Therefore, when the protrusion 42 is pinched and pulled by a finger, stress concentrates on the edge portions 41 of the groove 40 located on both sides of the protrusion 42. Thereby, the groove 40 is easily broken. Next, handling of the lens cap 10 configured as described above will be described.

First, when assembling the lens cap 10 to the photographing lens unit 12, the lens cap 10 is fixed to the lens frame 18 with an adhesive or a screw so that the pressing ring 36 positions and fixes the front lens group 14 to the lens frame 18. I do. Thus, the front lens group 14 is fixed and protected by the lens cap 10.

Next, when an optical performance inspection is performed before shipment of the photographic lens unit, inspection light is applied to the photographic lens unit 12 from the front of the lens cap 10. At this time, since the lens cap 10 is formed of transparent plastic, the optical performance test can be performed with the lens cap 10 attached.

Next, the lens cap 10 is removed from the retaining ring 36 when the photographing lens unit is used by attaching it to the camera. That is, when the projection 42 of the lens cap 10 is pinched with a finger and pulled in the detaching direction, first,
Stress concentrates on the edge portions 41, 41 of the groove 40, and the edge portions 41, 41 begin to break, and when the protrusion 42 is further pulled, the lens cap 10 gradually breaks along the groove 40, and Is completely removed from the retaining ring 36. As a result, the front lens group 14 is exposed, and the photographing lens unit 12 is ready for use. The press ring 36 remains in the photographing lens unit 12 and functions as a press ring for the front group lens 14.

As described above, according to the lens cap 10 of the present embodiment, since it is formed integrally with the press ring 36 constituting the photographing lens unit 12, it is not necessary to make a mold for a single lens cap, and the number of parts can be reduced. Is also reduced.
Therefore, in the present embodiment, the cost and the number of assembly steps required for the lens cap 10 can be reduced. Also,
In the present embodiment, since the lens cap 10 is formed integrally with the simple ring-shaped holding ring 36, the lens cap 10 can be manufactured with an inexpensive mold.

FIG. 5 is a sectional view of a principal part showing another embodiment of the lens cap 11, in which the same or similar members as those of the lens cap 10 shown in FIGS. The description is omitted. The lens cap 11 shown in FIG. 5 includes the lens cap 11 and the holding ring 36 without forming a gap between the projection 42 and the holding ring 36.
And are integrally formed. This lens cap 11
Then, there is no place where stress concentrates due to the tension of the projection 42,
If the depth of the groove 40 is formed to be large and the thickness of the broken portion is reduced, the lens cap 10 can be easily removed by pulling the projection 42.

In the present embodiment, the lens caps 10 and 11 of the front group lens 14 have been described. However, the lens cap of the rear group lens 16 is also integrally and detachably formed with a lens holding ring (not shown). It may be formed. A general cap may be applied to the rear lens group 16. In the present embodiment, the lens cap 1
Although 0 is formed integrally with the press ring 36, the present invention is not limited to this, and it may be formed integrally with other parts constituting the taking lens unit 12, such as the lens barrel 20 and the lens frame 18.

[0020]

As described above, according to the lens cap of the camera according to the present invention, the lens cap is formed integrally with some of the members constituting the photographing lens unit so as to be breakable. Costs and assembly man-hours can be reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a taking lens unit to which a lens cap according to an embodiment of the present invention is applied.

FIG. 2 is a front view of a lens cap.

FIG. 3 is a sectional view taken along line 3-3 in FIG. 2;

FIG. 4 is a sectional view taken along line 4-4 in FIG. 2;

FIG. 5 is a sectional view of a main part showing another embodiment of a lens cap.

[Explanation of symbols]

 10, 11 ... Lens cap 12 ... Shooting lens unit 14 ... Front group lens 16 ... Rear group lens 24 ... Iris unit 36 ... Holding ring 40 ... V-shaped groove 42 ... Protrusion

Claims (3)

[Claims] 1. A photographing lens unit in which a photographing lens is held by a lens barrel, wherein a lens cap for protecting the photographing lens is formed integrally with a part of the member constituting the photographing lens unit, and The photographing lens is exposed to the outside by breaking the lens cap from the member, and the member remains in the photographing lens unit and constitutes a part of the photographing lens unit. Camera lens cap. 2. A part of the photographing lens unit integrally formed with the lens cap is a lens pressing member for positioning the photographing lens with respect to the lens barrel. The lens cap of the described camera. 3. The camera lens cap according to claim 1, wherein said lens cap is made of a transparent member.