JPH02118504A - Lens barrel - Google Patents

Abstract

PURPOSE:To effectively prevent infiltration of dust and water, etc., while well maintaining operability by providing a magnetic field generating means to a region where an operating ring and a lens barrel are fitted and interposing magnetic fluid in the fitting region. CONSTITUTION:Annular pole pieces 3a, 3b are provided to the inner peripheral part of the region where the operating ring 1 and the lens barrel 6 are fitted. An annular permanent magnet 4 is crimped by these pieces. The part of the lens barrel 6 facing the permanent magnet 4 is constituted of a ferromagnetic material and the magnetic fluid 5 is inserted into the gap between both. The magnetic field generating means is formed of the ferromagnetic material part of the permanent magnet 4 and the lens barrel 6. The magnetic fluid 5 forms the annular magnetic fluid film in this constitution. the magnetic fluid 5 expels and stores the nonmagnetic materials to a place where there is a magnetic field even if the operating ring 1 is rotated. The magnetic fluid thus exhibits a good sealing function. the intrusion of the dust, water, etc., is well prevented without increasing the driving torque.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a lens barrel, and particularly to a photographic camera such as a photographic camera, a television camera, and a video camera, which has good focusing and zooming operability, and which is suitable for use under harsh conditions. The present invention relates to a lens barrel that is reliable even under environmental conditions, such as having dustproof and waterproof effects.

(Prior Art) Conventionally, so-called photographic cameras such as photographic cameras, television cameras, and video cameras have been used under various environmental conditions.
For example, it is used in places such as deserts where there is a lot of sandy wind, places with a lot of dirt and dust, and studios.

For this reason, many photographic cameras are designed to withstand various environmental conditions.

For example, when photographing in an environment with a lot of dust, dirt, sand, etc., these things may enter the lens barrel.
It is designed to prevent it from adhering to the lens surface and significantly lowering the optical performance, or from getting between the lens barrel and the operating ring that holds the lens, impairing operability and making it impossible to operate. .

Conventionally, in order to prevent dirt and water from entering the lens barrel from the outside or into the gap between the operation ring and the lens barrel, for example, in the lens barrel of a TV camera shade, a lens barrel was installed in the TV camera 9 as shown in FIG. A cover 8 may be applied to the attached photographic lens 7, or a seal such as an O-ring 10 may be applied to a part of the fitting area between the operating ring l and the fixed cylinder 6, which is the intrusion area for dust, as shown in FIG. It is constructed by sealing the materials.

(Problems to be Solved by the Invention) However, the method of covering the photographing lens has problems in that it becomes difficult to carry out quick photographing operations and the camera as a whole becomes larger.

In addition, the method of sealing the mating area with a sealing material increases the driving torque during operation, making it difficult to operate, and especially when operating the operating ring with a motor, the driving torque increases.
There were problems such as it not working properly.

The present invention effectively prevents dirt, water, etc. from entering the lens barrel from the outside while maintaining good operability by providing a magnetic fluid in a part of the fitting area between the operating ring and the lens barrel. To provide a lens barrel suitable for a photographic camera, a television camera, a video camera, etc., which is protected from the heat.

(Means for solving the gap) A magnetic field generating means is provided in the vicinity of the fitting area between the operating ring that holds the lens and the lens barrel that is displaced relative to the operating ring, and the fitting area is also provided. A magnetic fluid is interposed in a part of the lens barrel, and the magnetic fluid is held by the magnetic field generating means to form a lens barrel.

(Embodiment) FIG. 1 is a schematic diagram of a main part of an embodiment of the present invention, and shows the case where it is applied to, for example, a photographing system of a television camera.

In the figure, l is an operation ring, which holds, for example, a focusing lens group 2 inside.

Reference numeral 6 denotes a fixed lens barrel, which is attached to, for example, the main body of a television camera (not shown), and is made of a ferromagnetic material at least in a portion where a magnetic fluid, which will be described later, is located.

Although the lens barrel 6 is not shown, it may hold a lens group depending on the purpose.

4 is a permanent magnet having a ring shape and is provided on the inner circumference of the operating ring l. 3a and 3b are each pole pieces,
It has a ring shape and is arranged so as to sandwich the permanent magnet 4 therebetween.

Reference numeral 5 denotes a magnetic fluid, which is provided in a gap facing the permanent magnet 4 in the fitting area between the operating ring l and the lens barrel 6.

In this embodiment, the permanent magnet 41 and the ferromagnetic lens barrel 6 constitute one element of the magnetic field generating means.

In this embodiment, the pole piece 3a with the permanent magnet 4 sandwiched therebetween is created by setting each element as described above.

A magnetic field is generated in a concentrated manner in the gap between the lens barrel 6 and the lens barrel 6, which is a ferromagnetic material. The magnetic fluid 5 injected into this gap forms an annular magnetic fluid film.

This annular magnetic fluid film functions as a seal that effectively separates and shuts off the inside and outside of the lens barrel.

Even when the operation EM1 is rotated and slid around the lens barrel 6, the magnetic fluid 5 has the ability to exclude non-magnetic materials and remain in a place where there is a magnetic field, so the inside and outside of the lens barrel are always kept in good condition. Separated and maintained.

This maintains good operability of the operating ring without increasing the driving torque when driving the operating ring, and prevents dirt and water from entering from the outside and adhering to the lens surface, reducing optical performance. This is effectively prevented.

In the embodiment shown in Fig. 1, a magnetic fluid is interposed in the fitting area between the focusing operation ring and the lens barrel, but when a zoom lens is used, part of the sliding area of the zoom ring is interposed. Even if applied to the area, the same effect as mentioned above can be obtained.

(Effects of the Invention) As described above, according to the present invention, the magnetic field generating means is provided in a part of the fitting area between the operating ring and the lens barrel that moves relative to the operating ring, and By interposing the magnetic fluid at a predetermined position, it is possible to effectively prevent dirt, water, etc. from entering the lens barrel no matter what environmental conditions it is used in, and it also ensures that the lens barrel remains in good condition. In addition to the sealing, it is possible to achieve a lens barrel that does not increase sliding torque and maintains good operability of the operating ring.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a schematic diagram of main parts of an embodiment of the present invention, FIG.
Each figure is a schematic diagram of a conventional lens barrel. In the figure, 1 is an operating ring, 2 is a lens group, 3a and 3b are pole pieces, 4 is a permanent magnet, 5 is a magnetic fluid, 6 is a lens barrel, 7 is a photographic lens, 8 is a cover, 9 is a television camera, and 1O is It's an o-ring.

Claims (1)

[Claims] (1) A magnetic field generating means is provided near the fitting area between the operating ring that holds the lens and the lens barrel that is displaced relative to the operating ring, and a magnetic fluid is interposed in a part of the fitting area. and the magnetic fluid is held by the magnetic field generating means.