JPH0618960A - Lens hood - Google Patents

Abstract

PURPOSE:To enhance strength and further, improve a light shielding effect, on an attachable/detachable lens hood by providing a light shielding frame part extended in the radial direction of an inside diameter side. CONSTITUTION:A bayonet pawl part 1a for attaching the hood to a lens-barrel is provided in the vicinity of the inner surface of the rear end of a hood rear part 1, and moreover, a joint part 1b is set. A hood front part 2 is formed by resin molding, and has the shape of a petal, and moreover, the light shielding frame 2a used for reinforcement, as well, is extendedly formed in the radial direction, on a rear end inner surface side. On the other hand, on the rear end part of the hood front part 2, a joint part 2b in contact with the joint part 1b in the vicinity of the front end surface of the hood rear part 1, is provided. The hood front part 2 is fixed on the hood rear part 1 by a screw 3. Therefore, the hood is divided into two bodies, regardless of the fact that the light shielding frame 2a is provided on the inner periphery of the hood, so that cost can be reduced, and the strength of the hood can be enhanced, because the light shielding frame 2a itself serves as a reinforcing rib.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens hood mounted on a lens barrel.

[0002]

2. Description of the Related Art Conventionally, in most of resin molded lens hoods used for lens barrels, the main part of the hood main body is integrally formed.

[0003]

However, in the above conventional example, (1) the strength of the hood body tends to be insufficient.

(2) When a reinforcing rib or the like is provided to reinforce the hood body, the effective reinforcing rib becomes a so-called undercut during molding, which complicates the mold structure and leads to an increase in cost.

[0005]

According to the present invention, the hood body is divided into at least two parts in the optical axis direction, at least one of the parts is a molded product made of resin, and extends radially toward the inner diameter side. By providing the projected light-shielding collar portion, it is possible to increase the strength of a detachable lens hood, and it is possible to provide a lens hood having a large light-shielding effect.

[0006]

1 to 3 show a first embodiment of the present invention.

In the figure, reference numeral 1 denotes a hood rear portion, and a bayonet claw portion 1a for attaching to a lens barrel (not shown) is provided near the inner surface of the rear end. Further, a joint portion 1b is set near the front end surface of the hood rear portion 1. 2 is made of resin in the front part of the hood, has a petal shape as shown in the development view of FIG. 3, and a light-shielding brim 2a which also functions as a reinforcement is formed in the radial direction on the inner surface of the rear end. Has been done. The peripheral shape of the light-shielding brim 2a is not a perfect circle (a circle is a quadrangle) corresponding to the shape of the photographing screen (field of view) of the lens to which the present hood is applied, as shown by the hatched portion in FIG. The shape is set to be a little crushed. At the rear end of the hood front portion 2, there is provided a joint portion 2b which is in contact with the joint portion 1b near the front end surface of the hood rear portion 1. Three
Is a screw for fixing the hood front portion 2 to the hood rear portion 1 as apparent from FIG.

In the first embodiment, although the light-shielding collar is provided on the inner peripheral surface of the hood, the hood is made into two pieces, so that the cost can be reduced and the light-shielding collar itself serves as a reinforcing rib. Since it fulfills, the strength of the hood can be increased.

FIG. 4 shows a second embodiment of the present invention and is a sectional view of a portion according to FIG. The same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

In the second embodiment, the main part of the hood is made into three bodies, and there are two parts having a light-shielding brim, and these two parts are both made of resin.

That is, the hood middle part 4 is attached to the hood rear part 1 by the screws 3, and the hood front part 5 is attached to the hood middle part 4 by the screws 6. Light-shielding collars 4a and 5a also functioning as reinforcements are formed on the hood middle portion 4 and the hood front portion 5, respectively.

Both the first and second embodiments use a bayonet to attach the lens barrel (not shown), but this is one way to attach and detach the hood. The present invention is also applicable to the case where the screwing method or the attachment with screws is used without being too much.

[0013]

As described above, according to the present invention, the main portion of the hood main body is divided and joined into at least two in the optical axis direction, and at least one of them is a molded product made of resin, and at the inner diameter side. By providing a collar for light shielding, especially in the detachable lens hood,
(1) The strength can be increased by providing the collar portion.

(2) Since the hood main body is made into two bodies, it is easy to avoid an undercut shape due to the mold structure and it does not cost much.

(3) It is easy to set a light-shielding collar portion in the inner diameter portion of the middle portion of the hood body, and the light-shielding effect can be enhanced.

(4) By dividing in the optical axis direction, the hood main body is divided into the hood tip portion and the hood mounting portion (or intermediate portion) and the like. It can be changed and it is highly versatile. And so on.

Further, the periphery of the light-shielding brim is not a perfect circle,
Since the setting is made in correspondence with the shape of the field area (for example, the shooting screen), the optical characteristics can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view including an optical axis of a lens hood as a first embodiment.

FIG. 2 is a front view of the lens hood shown in FIG.

3 is a development view of the lens hood of FIG. 1 around an optical axis.

FIG. 4 is a sectional view of a lens hood as a second embodiment.

[Explanation of symbols]

 1 Hood rear part 2,5 Hood front part 4 Hood middle part 2a, 4a, 5a Light-shielding collar part

Claims (2)

[Claims] 1. A hood main body is divided and joined into at least two or more parts in the optical axis direction, at least one of which is a molded product made of resin, and which is for light shielding extending radially toward the inner diameter side. A lens hood with a collar. 2. The lens hood according to claim 1, wherein a peripheral shape of the flange is made non-circular corresponding to a shape of a field region.