JPH06222422A - Light leakage preventing device for camera - Google Patents

Abstract

PURPOSE:To eliminate the cause of leakage of light and also to lighten the burden on a lens barrel curtain, etc. CONSTITUTION:As to a light leakage preventing member for a camera including a ring-shaped light shielding member 2 installed so as to be slid in contact with the outer peripheral part of a photographic lens barrel 3 and a ring-shaped supporting member 1 for supporting the light shielding member 2 so as to prevent the leakage of light from a gap between an opening part installed on the front side of a camera main body and the outer peripheral part of the photographic lens barrel 3 which can be moved from the opening part in an optical axis direction, the light shielding member 2 is made of synthetic leather, and the ratio of the inside diameter of the light shielding member 2 to the outside diameter of the photographic lens barrel 3 is constituted so that the light shielding has a value between 0.9 and 0.95 in the case that the photographic lens barrel =1, and also, the ratio of the inside diameter of the supporting member 1 to the outside diameter of the photographic lens barrel 3 is constituted so as to satisfy the following inequality, and the supporting member 1 has a value between 1 and 1.05 in the case that the photographic lens barrel 3=1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light leakage prevention device for a camera in which a lens barrel is movable in an optical axis direction from an opening in the front surface of the camera body.

[0002]

2. Description of the Related Art Conventionally, these light leakage prevention devices for cameras prevent light from leaking from a gap between an opening of a camera body and an outer peripheral portion of a taking lens barrel which is movably provided in the opening along the optical axis. In order to prevent this, a ring-shaped light shielding member is provided so as to be slidably contactable with the outer peripheral portion of the taking lens. Then, as the material used for the light shielding member, there is flocked paper, rubber, cloth, or a combination of these materials.

[0003]

However, some flocked papers, rubbers, cloths, or combinations of these materials may cause light leakage, and in order to prevent light leakage with these materials, It has been necessary to increase the area where the light blocking member contacts the taking lens barrel (hereinafter referred to as the curtain contact area). Therefore, the frictional resistance generated between the taking lens barrel and the light blocking member becomes large, and the motor for driving the taking lens barrel and the light blocking member are burdened.

Further, no particular consideration has been given to the ratio of the inner diameter of the support member, the outer diameter of the taking lens barrel, and the inner diameter of the light shielding member. For this reason, if the ratio of the inner diameter of the core metal to the outer diameter of the taking lens barrel becomes larger than a certain amount, a sufficient curtain contact area cannot be obtained, which causes light leakage. If the ratio of the inner diameter of the core metal to the outer diameter of the barrel is smaller than a certain amount, the curtain contact area can be increased, but when the shooting lens barrel is driven, the area between the shooting lens barrel and the light blocking member is Increases the frictional resistance caused by, and in the worst case, the taking lens barrel stops.
If the ratio of the inner diameter of the light-shielding member to the outer diameter of the taking lens barrel increases to some extent or more, a sufficient curtain contact area cannot be obtained as in the above case, and light leakage cannot be completely prevented. If the ratio is smaller than a certain amount, the same problem as described above occurs, and the ratio of the outer diameter of the taking lens barrel to the inner diameter of the core metal and the inner diameter of the light shielding member is determined within a certain range. If not, there is a problem that the inner edge of the light shielding member is flexibly deformed due to the influence of humidity and temperature and the load of the light shielding member on the lens barrel, and light leakage occurs.

Therefore, in order to solve the above problems, it is an object of the present invention to eliminate the cause of light leakage and reduce the frictional resistance generated between the taking lens barrel and the light blocking member.

[0006]

In order to solve the above-mentioned problems, the present invention will be described with reference to FIGS. 1, 2 and 3. In the present invention, an opening provided in the front surface of the camera body and the opening are provided. A ring-shaped light shielding member (2) slidably provided on the outer peripheral portion of the taking lens barrel (3) that is movable in the optical axis direction in order to prevent light leakage from the gap. In a light leakage prevention member for a camera, including a ring-shaped support member (1) for supporting the light blocking member, the light blocking member (2) is formed of synthetic leather, and the inner diameter dimension (A )
And the outer diameter dimension (B) of the taking lens barrel is set such that the outer diameter dimension of the taking lens barrel is 1, the inner diameter dimension of the light shielding member is 0.9 or more and 0.95 or less. And the ratio of the inner diameter dimension (C) of the support member to the outer diameter dimension (B) of the taking lens barrel is 1 when the outer diameter dimension of the taking lens barrel is 1. The inner diameter of the support member was set to a value exceeding 1 and 1.05 or less.

[0007]

According to the present invention, the light-shielding member is formed of synthetic leather, and the ratio of the inner diameter of the light-shielding member to the outer diameter of the taking lens barrel and the inner diameter of the supporting member and the outside of the taking lens barrel are used. The special consideration was given to the ratio with the diameter, so that the curtain contact area with the outer periphery of the taking lens barrel can be sufficiently obtained and the inner edge of the curtain can be prevented from being deformed, and the opening of the camera body and the taking lens barrel can be prevented. It is possible to prevent light from leaking from the gap between the outer peripheral portion and the outer peripheral portion and reduce the frictional resistance generated between the taking lens barrel and the light blocking member.

[0008]

1 is an exploded perspective view of an embodiment of the present invention, and FIG. 2 is a vertical sectional view of this embodiment. In the camera of this embodiment, a taking lens barrel 3 (hereinafter referred to as a barrel) is incorporated in an opening provided on the front surface of the camera body 5, and the barrel 3 is provided with a helicoid screw 3a. The helicoid cylinder 4 is also provided with a helicoid screw 4a.

The helicoid screw 3a on the lens barrel side and the helicoid screw 4a on the helicoid barrel 4 mesh with each other. Therefore, by rotating the lens barrel 3 about the optical axis, the lens barrel 3 is moved along the optical axis direction 100 from the opening of the camera body 5 by the action of the helicoid screws 3a and 4a. Incidentally, a taking lens 6 is inserted in the lens barrel 3, and the taking lens 6 is fixedly held by the lens barrel 3 by a lens pressing ring 7.

A lens barrel curtain 2 slidably in contact with the outer peripheral portion of the lens barrel 3 is provided in a gap between the opening of the camera body 5 and the outer peripheral portion of the lens barrel 3. The lens barrel curtain 2 is made of synthetic leather and has a circular ring shape. The cored bar 1 for supporting the lens barrel curtain 2 also has a circular ring shape and is integrally bonded at the end surface of the lens barrel curtain 2.

The lens barrel curtain 2 and the core metal 1 are fitted to the outer peripheral portion of the lens barrel 3 as shown in FIG. 2, and at that time, the core metal 1 is positioned on the helicoid cylinder 4 side. It is provided so as to be sandwiched between the end surface of the helicoid cylinder 4 and the inner wall surface of the camera body 5. Therefore, even if the lens barrel 3 is moved with respect to the helicoid cylinder 4 in the optical axis direction, the lens barrel 3 slides on the outer peripheral portion of the lens barrel 3 without leaking light from the light blocking member.

FIG. 3 is a sectional view comparing the inner diameter A of the lens barrel curtain 2, the outer diameter B of the lens barrel 3 and the inner diameter C of the core metal. In the present embodiment, as shown in FIG. 3, the respective ratios of the inner diameter dimension A of the lens barrel curtain, the inner diameter dimension C of the core metal, and the outer diameter dimension B of the taking lens barrel are A: C: B = 0.
It is configured as 92: 1.04: 1. By the way, in this embodiment, the material of the lens barrel curtain 2 is "Bell Sade", which is a synthetic leather. The synthetic leather used in this example is different from the rubber used in the past.
Since the amount of deformation is large even with a weak force, the friction resistance with respect to the lens barrel is small even if the curtain contact area is large, and the lens barrel, the motor for driving the lens barrel, and the lens barrel curtain itself are not burdened.

By the way, in the prior art, in order to prevent light leakage from the gap between the opening of the camera body and the outer peripheral portion of the lens barrel with the flocked paper, the area of contact with the curtain or the flocked area per area of the lens barrel curtain is Although it was necessary to consider such as increasing the amount, the synthetic leather used in this example does not require any increase in the density of flocked paper per area of the lens barrel curtain, like flocked paper. Therefore, it is effective as a material used for the lens barrel curtain.

Further, in the prior art, since the respective ratios of the inner diameter of the cored bar, the outer diameter of the lens barrel, and the inner diameter of the lens barrel curtain were not taken into consideration, light leakage is completely prevented. If it is not possible, or even if light leakage can be prevented, the frictional resistance generated between the lens barrel and the lens barrel curtain may be increased, and the lens barrel curtain may
Due to the influence of humidity and the load on the lens barrel of the lens barrel curtain, there was a problem that the inner edge of the lens barrel curtain is deformed, but according to the light leakage prevention device in the present embodiment, special consideration should be given to their ratio. As a result, the curtain contact area with respect to the outer peripheral portion of the lens barrel 3 can be sufficiently obtained, deformation of the inner diameter edge of the lens barrel curtain can be prevented, and the gap between the opening of the camera body and the outer peripheral portion of the lens barrel 3 Can be completely prevented, and the frictional resistance generated between the lens barrel 3 and the lens barrel curtain 2 can be reduced, so that the lens barrel drive is not adversely affected.

In this embodiment, the ratio of the inner diameter dimension A of the lens barrel curtain, the inner diameter dimension C of the cored bar, and the outer diameter dimension B of the taking lens barrel is A: C: B = 0. .9
Although it is configured as 2: 1.04: 1, the present invention is not limited to these values, and the inner diameter dimension A of the lens barrel curtain 2 is a value satisfying 0.9 or more and 0.95 or less. It is sufficient if the inner diameter dimension C of the core metal is more than 1 and 1.05 or less.

[0016]

According to the present invention, the light-shielding member is made of synthetic leather, and the ratio of the inner diameter of the light-shielding member to the outer diameter of the taking lens barrel and the inner diameter of the supporting member and the taking lens barrel are used. Since we paid special attention to the ratio with the outer diameter of
It is possible to obtain a sufficient curtain contact area with the outer periphery of the taking lens barrel and prevent deformation of the inner diameter edge of the light blocking member, preventing light leakage from the gap between the opening of the camera body and the outer periphery of the taking lens barrel. In addition to being able to prevent it, it is possible to reduce the frictional resistance generated between the taking lens barrel and the light blocking member.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a configuration of components used as a light leakage prevention device for a camera according to the present invention.

FIG. 2 is a vertical cross-sectional view of the camera body in a state where the lens barrel curtain according to the embodiment is incorporated.

FIG. 3 is a comparative view of the dimensions of the core metal, the dimensions of the lens barrel, and the dimensions of the barrel curtain.

[Explanation of symbols]

 1: core metal 2: lens barrel curtain 3: lens barrel 4: camera body 5: camera cover 6: shooting lens 7: lens retaining ring

Claims (1)

[Claims] 1. In order to prevent light leakage from a gap between an opening provided on the front surface of a camera body and an outer peripheral portion of a taking lens barrel movable in the optical axis direction from the opening, the outer peripheral portion of the photographing lens barrel is prevented. A light leakage prevention member for a camera, comprising a ring-shaped light-shielding member that is slidably provided; and a ring-shaped support member for supporting the light-shielding member, wherein the light-shielding member is formed of synthetic leather, The ratio of the inner diameter of the light-shielding member to the outer diameter of the taking lens barrel is 0.9 or more and 0.95 when the outer diameter of the taking lens barrel is 1. If the ratio of the inner diameter of the supporting member and the outer diameter of the taking lens barrel is 1 and the outer diameter of the taking lens barrel is 1, It becomes a value that exceeds the inner diameter dimension and exceeds 1.05. Characterized by being configured to, camera light leakage prevention device.