JP2006171196A - Light shielding device of lens barrel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light shielding device of a lens barrel capable of reducing a load upon zoom barrel operation by the use of a light shielding rubber of a zoom barrel. <P>SOLUTION: A rib on an inner diameter part of a light shielding rubber is formed in a helical shape so as to fit the helicoid rotation direction of the barrel, thereby, a back and forth sliding amount of the light shielding rubber is reduced and the operation load is reduced. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a light shielding device for a zoom lens barrel of a camera.

  Conventionally, in a camera including a photographic lens barrel that moves in the optical axis direction, for example, a fixed cylinder fixed to the camera body, and an operating cylinder that is provided inside the fixed cylinder and operates forward and backward by a zoom operation or the like. The lens barrel provided with the light shielding member is used to shield the light incident from the gap between the fixed barrel and the working barrel. Various proposals have been made, such as 06-018321, Japanese Utility Model Laid-Open No. 06-037811.

  Hereinafter, a conventional example of a light shielding device for a camera manufactured by the applicant will be described with reference to FIGS.

  FIG. 1 shows an external view of a camera equipped with a zoom lens barrel. 1 is a camera body, 2 is a release button, and 3 is a zoom switch. Reference numerals 4 to 6 denote cylinders constituting a zoom lens barrel of the photographing lens of the camera, 4 is a fixed cylinder, 5 is a working cylinder, and 6 is a front group cylinder. The operating cylinder 5 engages with a helicoid provided on the inner periphery of the fixed cylinder 4 described later, and operates forward and backward while rotating. The front group cylinder 6 is guided by a straight cylinder (not shown) and is configured to operate forward and backward by a zoom operation without rotating. The operation of these zoom lens barrels is a well-known technique described in Japanese Patent No. 3221927 filed by the applicant of the present application and will not be described in detail. FIG. 4 is a cross section of the zoom lens barrel, showing a cross section of the engaging portion between the fixed cylinder 4 and the actuating cylinder 5 described above. A female helicoid 4 a is provided on the inner periphery of the fixed cylinder 4 and is engaged with the male helicoid 5 a of the working cylinder 5. The operating cylinder 5 receives a rotational force from a gear (not shown), and operates forward and backward while rotating by a zoom operation. A groove 4b is provided at the tip of the fixed cylinder 4, and a light shielding member 8 is disposed therein. The light shielding member 8 shields light incident from the gap (A in the figure) between the fitting portion of the fixed cylinder 4 and the working cylinder 5. Further, the light shielding member 8 is made of an elastic body such as rubber, is made slightly smaller in diameter than the outer diameter of the working cylinder 5, and is in close contact with the outer diameter of the working cylinder 5 in the assembled state.

FIG. 5 shows a cross-sectional view of the light shielding member 8. When a plurality of ribs 8 b are provided on the inner diameter portion of the light shielding member 8 and the operating cylinder 5 and the light shielding member 8 are in a sliding state during zoom operation. Even if the light shielding member 8 is deformed, it is provided for the purpose of maintaining close contact with the working cylinder 5.
No. 05-031634 No. 06-018321 Japanese Utility Model Publication No. 06-037811 Japanese Patent Registration No. 3221927

  However, in this conventional example, when the zoom lens barrel is actuated, for example, when the actuating barrel 5 is actuated in front of the camera (left side in the figure), the light shielding member 8 is also actuated forward and hits the front end surface of the groove 4b of the fixed barrel 4. If the rotation is restricted by contact, the outer circumference of the working cylinder 5 and the rib 8b of the light shielding member 8 are in a sliding state, but the outer circumference of the working cylinder 5 and the rib 8b of the light shielding member 8 are in line contact in the circumferential direction. Since sliding in a direction perpendicular to the close contact direction occurs, there is a problem that friction occurs at the contact portion between the light shielding member 8 and the working cylinder 5 and the operation becomes heavy. In addition, the light shielding member 8 is deformed by the operation in this direction, and the rib 8b is bent, and the adhesion between the outer periphery of the working cylinder 5 and the rib 8b of the light shielding member 8 cannot be maintained. .

  Therefore, in the present invention, a lens barrel that includes a photographic lens and operates the photographic lens in the optical axis direction, the lens barrel including at least a first lens barrel that is relatively disposed on the outer periphery, A second lens barrel disposed inside the first lens barrel; and a fitting portion between the first lens barrel and the second lens barrel, the first lens barrel; A ring-shaped light shielding member made of an elastic material that shields light incident from the fitting portion of the second lens barrel, and the light shielding member is formed in a spiral shape integrally with the light shielding member on the inner periphery thereof The above-described problem is to be solved by having the light-shielding rib formed on the surface.

  As described above, according to the present invention, it is possible to reduce the operation load of the zoom lens barrel with a simple configuration in which the inner rib shape of the light shielding member is a spiral shape, and the rib portion is twisted. This phenomenon can also be difficult to occur.

(First embodiment)
An embodiment of the present invention will be described with reference to FIGS. Since the conventional example has been described with reference to FIG. 2 shows a cross section of the zoom lens barrel as in FIG. 4, and the structure is the same as that of the conventional example of FIG. 4, and therefore the same component numbers are used. In other words, FIG. 2 shows a cross section of the engaging portion of the fixed cylinder 4 and the actuating cylinder 5 described above. A female helicoid 4a is provided on the inner periphery of the fixed cylinder 4 and is engaged with the male helicoid 5a of the actuating cylinder 5. Match. The operating cylinder 5 receives a rotational force from a gear (not shown), and operates forward and backward while rotating by a zoom operation. A groove 4b is provided at the tip of the fixed cylinder 4, and a light shielding member 7 is disposed therein. The light shielding member 7 shields light incident from the gap (A in the figure) between the fitting portions of the fixed cylinder 4 and the working cylinder 5. Further, the light shielding member 7 is made of an elastic body such as rubber, is made slightly smaller in diameter than the outer diameter of the working cylinder 5, and is in close contact with the outer diameter of the working cylinder 5 in the assembled state.

  FIG. 3 is a sectional view of the light shielding member 7 according to the present invention. A plurality of ribs 7 b are provided on the inner diameter portion of the light shielding member 7. The rib 7 b is formed in a spiral shape in the inner diameter portion of the light shielding member 7, and the spiral direction is the same as the female helicoid 4 a on the inner periphery of the fixed cylinder 4.

  The operation cylinder 5 rotates in FIG. 2 and is moved forward, for example, to the front of the camera (left side in the figure). The light shielding member 7 also moves forward to contact the front end surface of the groove 4b of the fixed cylinder 4. When the rotation is restricted, the outer periphery of the working cylinder 5 and the rib 7b of the light shielding member 7 are in a sliding state. The ideal form at this time will be described. If the lead of the female helicoid on the inner periphery of the fixed cylinder 4 is the same as the spiral lead of the rib 7b of the inner diameter portion of the light shielding member 7, the light shielding member 7 slides. Even in this state, since the helicoid and the lead of the rib 7b of the light shielding member 7 are the same, the helicoid slides in the line contact direction between the outer periphery of the actuating cylinder 5 and the rib 7b. An operation in the direction perpendicular to the line contact direction with 7b does not occur, and the rib 7b of the light shielding member 7 reduces the sliding load and does not cause a phenomenon such as twisting.

  In this embodiment, the rib 7b of the light shielding member 7 is set to have fewer leads than the helicoid. However, when compared with the conventional configuration in which the rib 7b is not formed in a spiral shape, the rib 7b and the actuating cylinder 5 are relatively lined. Since the sliding amount in the direction perpendicular to the contact direction is reduced, the operation load is reduced, and a phenomenon such as dripping is less likely to occur.

1 is an external view of a camera according to a first embodiment of the present invention. Cross section of zoom barrel Cross-sectional view of the light shielding member 7 Sectional view of a zoom lens barrel incorporating a conventional light shielding member 8 Sectional view of a conventional light shielding member 8

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Camera body 4 Fixed cylinder 5 Actuation cylinder 6 Front group cylinder 7 Light-shielding member

Claims (2)

A lens barrel that includes a photographic lens and operates the photographic lens in the optical axis direction. The lens barrel includes at least a first lens barrel that is disposed at a relatively outer periphery, and the first lens mirror. A second lens barrel disposed inside the barrel, and a fitting portion between the first lens barrel and the second lens barrel, the first lens barrel and the second lens mirror; A ring-shaped light shielding member made of an elastic body that shields light incident from the fitting portion of the tube,
The light shielding device for a lens barrel, wherein the light shielding member has a light shielding rib formed in a spiral shape integrally with the light shielding member on an inner periphery thereof. A lens barrel that includes a photographic lens and operates the photographic lens in the optical axis direction. The lens barrel includes at least a first lens barrel that is disposed at a relatively outer periphery, and the first lens mirror. A second lens barrel that is helicoidally coupled to the inside of the tube, and a fitting portion between the first lens barrel and the second lens barrel, the first lens barrel and the second lens A ring-shaped light shielding member made of an elastic body that shields light incident from the fitting portion of the lens barrel;
The light shielding member has a spiral light shielding rib formed integrally with the light shielding member on the inner periphery thereof in the same direction as the helical direction of the helicoids of the first lens barrel and the second lens barrel. A lens barrel light-shielding device.

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