JPH11174304A - Lens barrel and optical equipment equipped with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a lens surface from getting fogged even when the external barrel, etc., is warmed up by forming a lens holding barrel in a heat insulating structure. SOLUTION: Large-aperture lenses L1 to L3 are held on the inner periphery of the lens holding barrel/external barrel 1. The large-aperture lenses L1 to L3 are pressed along the optical axis and positioned by screwing lens pressing rings 2 to 4 made of metal such as aluminum to the inner periphery of the lens holding barrel/external barrel 1. The outer periphery of the lens holding barrel/external barrel 1 is applied with a heat-insulating coating 5 which has lower heat conductivity than that of the metal. Consequently, the heat conduction between the outside and inside of the lens barrel can be made slow. Consequently, the cooling of lenses, especially, of the large-aperture lens L2 caused by water at the time of photography in the rain and the warming of the lens holding barrel/external barrel 1, the lens pressing rings 2 to 4, and air between lenses by the heat of the hand and the human body touching the lens barrel/ thereafter, can be made slow.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens barrel having a heat insulating structure for preventing fogging of a lens.

[0002]

2. Description of the Related Art Conventionally, in a large-sized lens barrel such as a super-telephoto lens, a large-diameter lens disposed near the distal end of the barrel is directly held by an outer cylinder also serving as a lens holding barrel, or an external component. And a lens holding cylinder which is screwed to the inner periphery of the outer cylinder. The outer cylinder and the lens holding cylinder are often made of metal such as aluminum.

FIG. 10 shows an example of a conventional lens barrel. 101 is an outer cylinder which also serves as a lens holding cylinder,
L1, L2, and L3 are large-diameter lenses held on the inner periphery of the outer cylinder 101 near the tip of the lens barrel. 10
Reference numerals 2, 103, and 104 denote lens retaining rings attached to the inner periphery of the outer cylinder 101 to retain the lenses L1, L2, and L3 in the optical axis direction. These lens retaining rings are also made of metal such as aluminum. Here, since the outer cylinder and the lens holding cylinder are made of metal, when the lens barrel is wetted and the outer cylinder and the like are cooled in shooting in rainy weather, the air and the lens therein are also easily cooled, Immediately after shooting in the rain or the like, if the outer cylinder or the like is touched with a hand to wipe off water droplets attached to the outer cylinder or the like, the outer cylinder or the like and the internal air are warmed by the heat of the human body.

[0004]

However, a large-diameter lens having a large heat capacity and a low heat transfer coefficient does not easily warm up to a thick portion, so that a temperature difference occurs on the lens surface. For this reason, there is a problem that the surface of the lens which is in contact with the internal air having a large volume, which is likely to be vaporized, of the lens having the largest heat capacity is fogged, so that it becomes impossible to take a picture.

This will be described with reference to FIG. 10. When the cooled outer cylinder 101 is touched with a hand, the outer cylinder 101 is heated by heat from a human body, and the lens press rings 10, 103, Heat is transmitted to 104 and the lenses L1, L2, and L3, and further to the air between the lenses L1 and L2 and the air between the lenses L2 and L3. However, since the heat transfer coefficient of the lens is lower than that of metal or air, a temperature difference occurs on the lens surface. In particular, fogging occurs on the surface of the lens L2 having the largest heat capacity in contact with the internal air between the large volumes L2 and L3, which are likely to be steamed.

Accordingly, the present invention provides a large lens barrel such as a super-telephoto lens in which metal is used for an outer cylinder and a lens holding cylinder. It is an object of the present invention to provide a lens barrel in which the occurrence of a lens is hardly caused.

[0007]

In order to achieve the above object, according to the present invention, in a lens barrel having a lens holding tube for holding a lens at an inner periphery, the lens holding tube has a heat insulating structure.

Specifically, a material having a lower thermal conductivity than the material of the lens holding barrel is coated on the outer or inner circumferential surface of the lens holding barrel, or the lens holding barrel is coated on the outer or inner circumference of the lens holding barrel. For example, a member made of a material having a lower thermal conductivity than the material of the cylinder is provided.

Further, in a lens barrel having a lens holding tube for holding a lens on the inner periphery and an outer tube for covering the outer periphery of the lens holding tube, an air layer is formed between the lens holding tube and the outer tube. Further, a material having a lower thermal conductivity than the material of the outer cylinder is coated on the outer peripheral surface or the inner peripheral surface of the outer cylinder, or the outer cylinder or the outer peripheral surface of the outer cylinder has a higher thermal conductivity than the material of the outer cylinder. Or a member made of a low material.

[0010] By using a heat insulating structure for the lens holding cylinder and the outer cylinder as described above, the lens in the outer cylinder is hardly cooled even if it is wet in rainy weather, and the cooled outer cylinder or the like is heated by the human body. Therefore, it is possible to make it difficult for the lens to be heated even if it is heated, and it is possible to prevent clouding from occurring on the lens surface.

It is also effective to prevent the lens from fogging by providing an air layer between the outer cylinder and the lens holding cylinder with a sufficient thickness for heat insulation.

Further, according to the present invention, there is provided a lens barrel having a lens holding tube for holding a lens at an inner periphery thereof, and a lens holding member attached to the inner periphery of the lens holding tube for holding the lens in an optical axis direction. , A lens holding member made of a material having a lower thermal conductivity than the material of the lens holding cylinder,
Even if the surface of the lens holding member is coated with a material having a lower thermal conductivity than the material of the lens holding cylinder, heat transfer from the lens holding cylinder etc. to the lens can be suppressed, preventing the lens from fogging. It is.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIG. 1 shows a lens barrel according to a first embodiment of the present invention. In this drawing, L1, L2, and L3 are large-diameter lenses disposed near the tip of the lens barrel, and 1 is a lens holding cylinder and outer cylinder (hereinafter, referred to as an outer cylinder) formed of metal such as aluminum. It is. On the inner periphery of the outer cylinder 1, lenses L1,
L2 and L3 are held. Reference numerals 2, 3, and 4 denote lens retaining rings made of metal such as aluminum, which are screwed to the inner periphery of the outer cylinder 1 to form large-diameter lenses L1, L2.
2, L3 are positioned in the direction of the optical axis.

Reference numeral 5 denotes a heat insulating coating (rubber coating or the like) having a lower thermal conductivity than the metal applied to the outer periphery of the outer cylinder 1.

Since the heat transfer between the outside and the inside of the lens barrel can be slowed by applying the heat insulating coating 5 to the outer periphery of the outer cylinder 1 in this manner, it is possible to prevent water from getting wet during rain photography. Cooling the lens (especially the lens L2),
Thereafter, it is possible to delay the warming of the outer cylinder 1, the lens holding rings 2, 3, 4 and the air between the lenses by the heat of the hand (human body) touching the outer cylinder 1. Therefore, no temperature difference is generated on the surface of the large-aperture lens L2 having the largest heat capacity among the three lenses, and this lens L2
Fogging can be prevented.

In addition, the present embodiment can be implemented only by applying heat insulation coating to the outer periphery of the conventionally used outer cylinder 1, so that it is possible to prevent fogging of the lens without complicating the structure of the lens barrel. it can.

(Second Embodiment) FIG. 2 shows a second embodiment of the present invention.
1 illustrates a lens barrel according to an embodiment. Note that the basic configuration of the present embodiment is the same as that of the first embodiment, and therefore, the same components as those of the first embodiment are denoted by the same reference numerals and description thereof will be omitted.

The present embodiment differs from the first embodiment in that the inner periphery of the outer cylinder 1 is provided with a heat insulating coating (rubber coating or the like) 5 'having a lower thermal conductivity than metal.

Since the heat transfer between the outside and the inside of the lens barrel can be slowed by applying the heat insulating coating 5 'to the inner periphery of the outer cylinder 1 in this manner, the water incurred when photographing in the rain. The lens (particularly, the lens L2) is cooled by
Thereafter, it is possible to delay that the lens holding rings 2, 3, and 4 and the air between the lenses are warmed by the heat of the hand (human body) touching the outer cylinder 1. Therefore, no temperature difference is generated on the surface of the large-aperture lens L2 having the largest heat capacity among the three lenses, and the fogging of the lens L2 can be prevented.

In addition, the present embodiment can be implemented only by applying the heat insulating coating 5 'to the inner periphery of the conventionally used outer cylinder 1, so that the fogging of the lens can be prevented without complicating the structure of the lens barrel. can do.

(Third Embodiment) FIG. 3 shows a third embodiment of the present invention.
1 illustrates a lens barrel according to an embodiment. Note that the basic configuration of the present embodiment is the same as that of the first embodiment, and therefore, the same components as those of the first embodiment are denoted by the same reference numerals and description thereof will be omitted.

In the present embodiment, instead of applying heat insulation coating to the outer periphery of the outer cylinder 1 as in the first embodiment, a material (molybdenum or the like) having a lower heat transfer coefficient than metal is used for the outer periphery of the outer cylinder 1. The formed heat insulating member 6 is attached.

By providing the heat insulating member 6 on the outer periphery of the outer cylinder 1 as described above, heat transfer between the outside and the inside of the lens barrel can be slowed down. That the lens (especially lens L2) is cooled,
Thereafter, it is possible to delay the warming of the outer cylinder 1, the lens holding rings 2, 3, 4 and the air between the lenses by the heat of the hand (human body) touching the outer cylinder 1. Therefore, no temperature difference is generated on the surface of the large-aperture lens L2 having the largest heat capacity among the three lenses, and this lens L2
Fogging can be prevented.

In addition, the present embodiment can be implemented only by attaching the heat insulating member 6 to the outer periphery of the conventionally used outer cylinder 1, so that the fogging of the lens can be prevented without complicating the structure of the lens barrel. Can be.

(Fourth Embodiment) FIG. 4 shows a fourth embodiment of the present invention.
1 illustrates a lens barrel according to an embodiment. Note that the basic configuration of the present embodiment is the same as that of the first embodiment, and therefore, the same components as those of the first embodiment are denoted by the same reference numerals and description thereof will be omitted.

In the present embodiment, instead of applying heat-insulating coating to the inner periphery of the outer cylinder 1 as in the second embodiment, a material having a lower heat transfer coefficient than a metal (such as molybdenum) is applied to the inner periphery of the outer cylinder 1. ) Is attached.

In this embodiment, the lenses L1, L2, L3 are held on the inner periphery of the heat insulating member 6 ', and the lens holding rings 2, 3, 4 are screwed on the inner periphery of the heat insulating member 6'. Thus, the positioning of the lenses L1, L2, and L3 in the optical axis direction is performed.

By providing the heat insulating member 6 'on the inner periphery of the outer cylinder 1 as described above, the heat transfer between the outside and the inside of the lens barrel can be slowed down, so that the water is not wet when photographing in the rain. The cooling of the lens (particularly the lens L2) due to the above and the like, and the delay of the warming of the lens holding rings 2, 3, 4 and the air between the lenses due to the heat of the hand (human body) touching the outer cylinder 1 thereafter. it can. Therefore, no temperature difference is generated on the surface of the large-aperture lens L2 having the largest heat capacity among the three lenses, and the fogging of the lens L2 can be prevented.

In addition, the present embodiment can be implemented only by attaching the heat insulating member 6 'to the inner periphery of the conventionally used outer cylinder 1, so that the fogging of the lens can be prevented without complicating the structure of the lens barrel. can do.

(Fifth Embodiment) FIG. 5 shows a fifth embodiment of the present invention.
1 illustrates a lens barrel according to an embodiment. In this figure, L1, L2, and L3 are large-diameter lenses disposed near the tip of the lens barrel, and 11 is a lens holding cylinder formed of metal such as aluminum. Lenses L1, L2, and L3 are held on the inner periphery of the lens holding tube 11. Reference numerals 12, 13, and 14 denote lens retaining rings made of metal such as aluminum, which are screwed to the inner periphery of the lens holding cylinder 11 to form large-diameter lenses L1, L2, L.
3 is positioned in the optical axis direction.

Reference numeral 17 denotes an outer cylinder that covers the outer periphery of the lens holding cylinder 11, and is formed of a metal such as aluminum. The outer periphery of the distal end of the lens holding tube 11 is screw-connected to the inner periphery of the outer tube 17, and a fitting portion 11 a formed near the screw connection portion of the lens holding tube 11 is fitted to the inner periphery of the outer tube 17. I agree.

Here, the fitting portion 11a is provided in the lens holding cylinder 1
1 is formed at a position distant in the optical axis direction from the holding portions of the lenses L2 and L3 having a relatively large heat capacity, and a portion other than the fitting portion between the lens holding tube 11 and the outer tube 17 includes: An air layer 18 is formed.

As described above, the contact portion between the lens holding tube 11 and the outer tube 17 is separated from the holding portions of the lenses L2 and L3 having a relatively large heat capacity, and the air layer 18 is formed on the outer periphery of the holding portions of the lenses L2 and L3. By doing so, the heat transfer between the outside and the inside of the lens barrel can be slowed down.
2) is cooled, and then the lens holding cylinder 11 and the lens holding ring 1 due to the heat of the hand (human body) touching the outer cylinder 17
Heating of the air between the lenses 2, 13, 14 and the lenses can be delayed. Therefore, no temperature difference is generated on the surface of the large-aperture lens L2 having the largest heat capacity among the three lenses, and the fogging of the lens L2 can be prevented.

(Sixth Embodiment) FIG. 6 shows a sixth embodiment of the present invention.
1 illustrates a lens barrel according to an embodiment. Since the basic configuration of this embodiment is the same as that of the fifth embodiment, the same reference numerals are given to the same components as those of the fifth embodiment, and the description will not be repeated.

In the present embodiment, in addition to forming the air layer 18 between the lens holding cylinder 11 and the outer cylinder 17 as in the fifth embodiment, the material of the outer cylinder 17 ( A heat insulating coating 19 made of a material (molybdenum or the like) having a lower heat transfer coefficient than that of metal is applied. By providing the air layer 18 and the heat insulating coating 19 in this manner, the heat transfer between the outside and the inside of the lens barrel can be slowed down more than in the fifth embodiment. The fogging of the large-aperture lens L2 having the largest heat capacity among the three lenses can be more effectively prevented.

(Seventh Embodiment) FIG. 7 shows a sixth embodiment of the present invention.
1 illustrates a lens barrel according to an embodiment. Since the basic configuration of this embodiment is the same as that of the fifth embodiment, the same reference numerals are given to the same components as those of the fifth embodiment, and the description will not be repeated.

In the present embodiment, in addition to forming the air layer 18 between the lens holding cylinder 11 and the outer cylinder 17 as in the fifth embodiment, the material of the outer cylinder 17 is provided on the inner periphery of the outer cylinder 17. A heat insulating coating 19 'made of a material (molybdenum or the like) having a lower heat transfer coefficient than (metal) is applied.

By providing the air layer 18 and the heat-insulating coating 19 'in this manner, the heat transfer between the outside and the inside of the lens barrel can be slowed down more than in the fifth embodiment. Therefore, it is possible to more effectively prevent the large-aperture lens L2 having the largest heat capacity among the three lenses from fogging.

(Eighth Embodiment) FIG. 8 shows an eighth embodiment of the present invention.
1 illustrates a lens barrel according to an embodiment. Since the basic configuration of this embodiment is the same as that of the fifth embodiment, the same reference numerals are given to the same components as those of the fifth embodiment, and the description will not be repeated.

In the present embodiment, in addition to forming the air layer 18 between the lens holding cylinder 11 and the outer cylinder 17 as in the fifth embodiment, the material of the outer cylinder 17 ( A heat insulating member 20 made of a material (molybdenum or the like) having a lower heat transfer coefficient than that of metal is attached.

By providing the air layer 18 and the heat insulating member 20 in this manner, compared to the fifth embodiment,
Since the heat transfer between the outside and the inside of the lens barrel can be further reduced, it is possible to more effectively prevent the large-aperture lens L2 having the largest heat capacity among the three lenses from fogging.

(Ninth Embodiment) FIG. 9 shows a ninth embodiment of the present invention.
1 illustrates a lens barrel according to an embodiment. Since the basic configuration of this embodiment is the same as that of the fifth embodiment, the same reference numerals are given to the same components as those of the fifth embodiment, and the description will not be repeated.

In the present embodiment, in addition to forming the air layer 18 between the lens holding cylinder 11 and the outer cylinder 17 as in the fifth embodiment, the material of the outer cylinder 17 is provided on the inner periphery of the outer cylinder 17. A heat insulating member 20 'made of a material (molybdenum or the like) having a lower heat transfer coefficient than (metal) is attached.

In the present embodiment, the outer periphery of the distal end of the lens holding cylinder 11 is screwed to the screw formed on the heat insulating member 20 '.

By providing the air layer 18 and the heat insulating member 20 'together in this manner, the heat transfer between the outside and the inside of the lens barrel can be made slower than in the fifth embodiment. Therefore, it is possible to more effectively prevent the large-aperture lens L2 having the largest heat capacity among the three lenses from fogging.

In the sixth to ninth embodiments,
Although the case where the heat insulation coating or the heat insulation member is applied to the outer circumference or the inner circumference of the outer cylinder 17 has been described, the heat insulation coating or the heat insulation member may be applied to the outer circumference or the inner circumference of the lens holding cylinder 11. . Further, in the first to fourth embodiments and the sixth to ninth embodiments, the case where the heat insulating coating or the heat insulating member is provided on almost the entire outer circumference or inner circumference of the outer cylinders 1 and 17 has been described. , 17 may be provided with a heat-insulating coating or a heat-insulating member only on the portion that is most effective in preventing fogging of the lens.

In each of the above embodiments, the case where the lens holding rings 2, 3, 4, 12, 13, and 14 are made of the same metal as the outer cylinders 1 and 17 and the lens holding cylinder 11 has been described. The holding ring is made of a material (molybdenum, etc.) having a lower heat transfer coefficient than the outer cylinder or the lens holding cylinder, or a material (rubber, etc.) having a lower heat transfer rate than the outer cylinder or the lens holding tube is formed on the surface of the lens holding ring. Or the like, heat transfer between the outside and the inside of the lens barrel and heat transfer to the lens can be delayed. That is, by combining the lens holding ring with the above-described embodiments as a heat insulating structure, the effect of preventing clouding of the lens can be further enhanced.

Further, in each of the above embodiments, the lens barrel alone has been described. However, the present invention can be applied to a camera having a similar lens barrel configuration and optical equipment other than the camera (such as binoculars). .

[0049]

As described above, according to the present invention,
The lens holding tube and outer tube have a heat-insulating structure, so that the lens inside the lens tube is hardly cooled even when exposed to water in rainy weather, and even if the cooled outer tube is heated by the heat of the human body. Can be less likely to be warmed and fogging on the lens surface can be prevented.

If an air layer having a sufficient thickness for heat insulation is provided between the outer cylinder and the lens holding cylinder, or if a lens holding member provided in the lens holding cylinder is made to have a heat insulating structure, the lens can be re-formed. Fogging can be more effectively prevented.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a lens barrel according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a main part of a lens barrel according to a second embodiment of the present invention.

FIG. 3 is a sectional view of a main part of a lens barrel according to a third embodiment of the present invention.

FIG. 4 is a sectional view of a main part of a lens barrel according to a fourth embodiment of the present invention.

FIG. 5 is a sectional view of a main part of a lens barrel according to a fifth embodiment of the present invention.

FIG. 6 is a sectional view of a main part of a lens barrel according to a sixth embodiment of the present invention.

FIG. 7 is a sectional view of a main part of a lens barrel according to a seventh embodiment of the present invention.

FIG. 8 is a sectional view of a main part of a lens barrel according to an eighth embodiment of the present invention.

FIG. 9 is a sectional view of a main part of a lens barrel according to a ninth embodiment of the present invention.

FIG. 10 is a sectional view of a main part of a conventional lens barrel.

[Explanation of Signs] L1, L2, L3: Large-diameter lens 1 Lens holding tube and outer tube 11 Lens holding tube 17 Outer tube 2, 3, 4, 12, 13, 14 Lens press ring 5, 19 Insulation coating 6, 20 Insulation material

Claims (14)

[Claims] 1. A lens barrel having a lens holding barrel for holding a lens at an inner periphery thereof, wherein the lens holding barrel has a heat insulating structure. 2. The lens barrel according to claim 1, wherein a material having a lower thermal conductivity than a material of the lens holding cylinder is coated on an outer peripheral surface or an inner peripheral surface of the lens holding cylinder. 3. The lens according to claim 1, wherein a member made of a material having a lower thermal conductivity than a material of the lens holding cylinder is provided on an outer periphery or an inner periphery of the lens holding cylinder. Lens barrel. 4. A lens barrel comprising: a lens holding tube for holding a lens at an inner periphery; and an outer tube for covering the outer periphery of the lens holding tube, wherein the outer tube has a heat insulating structure. Lens barrel. 5. The lens barrel according to claim 4, wherein a material having a lower thermal conductivity than a material of the outer cylinder is coated on an outer peripheral surface or an inner peripheral surface of the outer cylinder. 6. The lens barrel according to claim 4, wherein a member made of a material having a lower thermal conductivity than a material of the outer cylinder is provided on an outer circumference or an inner circumference of the outer cylinder. . 7. A lens barrel having a lens holding tube for holding a lens on an inner periphery thereof and an outer tube for covering the outer periphery of the lens holding tube, wherein an air space is provided between the lens holding tube and the outer tube. A lens barrel characterized in that a lens barrel is formed. 8. The lens holding barrel holds a plurality of lenses, and the air layer is formed on an outer periphery of a holding part of a lens having a largest heat capacity among the plurality of lenses in the lens holding barrel. The lens barrel according to claim 7, wherein: 9. A lens barrel comprising: a lens holding barrel for holding a lens at an inner circumference; and a lens holding member attached to the inner circumference of the lens holding barrel for holding the lens in an optical axis direction. A lens barrel characterized in that the holding member has a heat insulating structure. 10. The lens barrel according to claim 9, wherein the lens holding member is made of a material having a lower thermal conductivity than a material of the lens holding barrel. 11. The lens barrel according to claim 9, wherein a material having a lower thermal conductivity than a material of the lens holding cylinder is coated on a surface of the lens holding member. 12. The lens barrel according to claim 1, wherein the lens holding barrel is made of metal. 13. The lens barrel according to claim 1, wherein the lens is a large-diameter lens held by the lens holding barrel near the tip of the lens barrel. 14. An optical apparatus comprising the lens barrel according to claim 1. Description: