JP2002258139A - Lens barrel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain the miniaturization and weight reduction of a lens barrel. SOLUTION: In the lens barrel 10C constituted by bisecting the lens barrel 20C into a front lens barrel 26 and a rear lens barrel 27 in the length direction, an aperture part 27c is formed at one part of the outer peripheral part of the rear lens barrel 29, an inverse U-shaped projected part 27d opposed to the aperture part 27c across an optical axis K is formed so as to be projected from the outer peripheral part of the rear lens barrel 27, and the end part of the bracket 57 of an iris assembly body 55 is inserted from the aperture part 27c so that an iris 50 is aligned with the optical axis K and also the end part of the bracket 57 is housed in the inside of the inverse U-shaped projected part 27d, and furthermore, at least either a motor assembly body 45 for a variable power lens or a motor assembly body 75 for a focus lens is attached along the outer peripheral part of the rear lens barrel 27 whose height is smaller than that of the inverse U-shaped projected part 27d.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens barrel used for a portable video camera or the like.

[0002]

2. Description of the Related Art In general, a lens barrel used for a portable video camera is required to be small and light, and accordingly, various structural forms have been developed.

FIG. 1 is a diagram schematically showing a general lens barrel.

In a general lens barrel 10 schematically shown in FIG. 1, a lens barrel 20 forming an external appearance is divided into two or more in order to assemble a plurality of constituent members inside as described later. However, here, the lens barrel 10
Is shown without dividing the lens barrel 20 in order to conceptually explain the above.

In the lens barrel 20, a front lens (group) 3 for photographing the subject H from the front side to the rear side.
0, a variable power lens (group) 40 movable in the optical axis direction for zooming the subject image captured by the front lens (group) 30, and an open / close mechanism for adjusting the light amount of the subject image A flexible iris 50, a fixed master lens (group) 60, and a focus lens (group) 70 movable in the optical axis direction in order to adjust the focus of the subject image in cooperation with the fixed master lens (group) 60. An optical low-pass filter 80 for preventing spurious signals due to high-frequency components of the subject image,
An image sensor 82, which is attached via an optical low-pass filter 80 and a rubber 81 and photoelectrically converts a subject image, is provided in order. The rear side of the lens barrel 20 is closed by an image sensor holder 83 for fixing the image sensor 82. I have a lid.

[0006] The subject image photographed by the front lens (group) 30, the variable power lens (group) 40, the fixed master lens (group) 60, and the focus lens (group) 70 is CCD.
When the image is formed on the image sensor 82 and the subject image is photoelectrically converted by the image sensor 82, each lens (group) 30, 40,
Reference numerals 60 and 70 use a single lens or a plurality of lens groups.

Here, in a general lens barrel 10, a method of dividing the barrel 20 into two or more is as follows.
(For example, a method of dividing into a plurality of cylinders), a method of dividing along the radial direction of the lens barrel 20 (for example, a method of dividing into a plurality of half cylinders), The method can be roughly divided into a method of dividing along the length direction and the radial direction. In the present invention, a method of dividing along the length direction of the lens barrel 20 is employed as described later. A conventional example will be described with reference to FIGS.

FIG. 2 shows an example of a conventional lens barrel.
FIG. 3 is an exploded view showing a structure in which a lens barrel is divided into two along the length direction. FIG. 3 shows a structure in a case where the lens barrel is divided into three along the length direction in another example of the conventional lens barrel. It is the exploded view shown.

First, as shown in FIG. 2, in an example of a conventional lens barrel 10A, a barrel 20A is divided into a front barrel 21 and a rear barrel 22 along the length direction. The two lens barrels 21 and 22 are mass-produced by a molding die using a resin material or a die-cast material.

The front lens barrel 21 has a front lens (group) 30 fitted in a round hole 21a formed along the optical axis K.

On the other hand, the rear barrel 22 has a large first round hole 22a formed in the front lens 30 side, which is long in the longitudinal direction. The opening 22b is formed so as to be opened with a small length in the longitudinal direction, and a small-diameter second round hole 22c is slightly formed in the longitudinal middle part following the first round hole 22a in the longitudinal direction. A third round hole 22d having a length larger than the second round hole 22c is formed following the second round hole 22c.

A first lens frame 41 in which a variable power lens (group) 40 is fitted into a large-diameter first round hole 22a formed in front of the rear barrel 22 has two long guide shafts 90.
A fixed master lens (group) 60 is fitted into a small-diameter second round hole 22c provided movably in the optical axis direction along only one side (shown only on one side) and formed at an intermediate portion in the longitudinal direction. Further, the third round hole 22 formed on the imaging device 82 side
The second lens frame 71 in which the focus lens (group) 70 is fitted into the two long guide shafts 90
Are provided so as to be movable in the optical axis direction.

At this time, the two guide shafts 90 pass through the outside of the second round hole 22c formed in the rear lens barrel 22, and form an image with the front lens barrel 21 in which the front lens (group) 30 is fitted. It is laid in parallel with the optical axis K between an image sensor holder 83 to which the element 82 is attached and a center-to-axis distance in front and behind the plane of the paper.

A variable-magnification lens motor assembly 4 is provided on the outer peripheral portion of the large-diameter first round hole 22a formed in the rear lens barrel 22.
5 and a focus lens motor assembly 75 are attached before and after the paper.

The above-described motor assembly 45 for the variable power lens.
Is a connecting member (not shown) for converting the movement direction between the worm 47 and the first lens frame 41, which rotatably supports the worm 47 attached to the shaft of the variable-magnification lens motor 46 on the bracket 48. By coupling and converting the rotation of the worm 47 into a linear motion, the first lens frame 41 in which the variable power lens (group) 40 is fitted can linearly reciprocate in the optical axis direction.

On the other hand, the above-described focus lens motor assembly 75 also rotatably supports the worm 77 attached to the shaft of the focus lens motor 76 on the bracket 78, and the worm 77 and the second lens frame 71. The second lens frame 71 in which the focus lens (group) 70 is fitted is moved in the direction of the optical axis by converting the rotation of the worm 47 into a linear motion by connecting It can reciprocate linearly.

An iris assembly 55 is inserted into the opening 22b slightly below the fixed master lens 60 and in the opening 22b of the first round hole 22a of the rear lens barrel 22 at a portion below the right end in the drawing. Have been. At this time, the opening 22b formed in the lower part of the outer periphery of the rear barrel 22 is formed by a slide molding die that slides only this part in a direction orthogonal to the optical axis K.

In the iris assembly 55 described above, the iris motor 56 is attached to the lower end portion of the bracket 57, and the iris 50 is attached to the intermediate portion of the bracket 57 so as to coincide with the optical axis K. By transmitting the torque of 56 to the iris 50 via a transmission member (not shown), the iris 50 can be freely opened and closed.

At this time, the outer dimensions of the rear lens barrel 22 depend on the outer dimensions of the iris assembly 55. That is,
The upper end in the figure of the bracket 57 to which the iris 50 is attached is inserted from the opening 22b formed in the lower part of the rear lens barrel 22 so that the iris 50 coincides with the optical axis K.
The iris motor 56 is exposed to the outside of the outer peripheral portion of the rear lens barrel 22, and the upper end portion of the bracket 57 in the drawing is inserted just before it abuts the first round hole 22 a of the rear lens barrel 22. The diameter of the first round hole 22a of the rear barrel 22 and the diameter of the outer peripheral portion of the first round hole 22a are determined by the position of the upper end portion of the bracket 57 in the figure.

When assembling the above-described members from the direction of the arrow, the motor assembly 45 for the variable power lens and the motor assembly for the focus lens are particularly arranged along the outer peripheral portion of the first round hole 22a of the rear lens barrel 22. Since the diameter of the first round hole 22a of the rear lens barrel 22 becomes larger due to the dimension of the upper end portion of the bracket 57 of the iris assembly 55 when the three-dimensional lens 75 is mounted in an exposed state, the conventional lens is used. One example of the lens barrel 10A has a structure that cannot be reduced in size and weight.

Therefore, in order to reduce the size and weight of the conventional lens barrel 10A, the other example of the conventional lens barrel 10B shown in FIG. Along the front lens barrel 23, the middle lens barrel 24, and the rear lens barrel 25, the lens barrel is divided into three parts. Here, each of the lens barrels 23 to 25 is formed using a resin material or a die-cast material by a molding die. Mass-produced.

The front lens barrel 23 has a front lens (group) 30 fitted in a round hole 23a formed along the optical axis K.

In the middle lens barrel 24, a large-diameter first round hole 24a is formed on the variable power lens 40 side with a small length in the longitudinal direction, and the first round hole 24a follows the first round hole 24a. Round hole 24a
A second round hole 24b having a slightly smaller diameter is formed to be long, and an opening 24c is formed in a lower portion of the second round hole 24b at the right end in the drawing.
Is opened at a small length with respect to the longitudinal direction, and the second
An inverted L-shaped protruding piece 24d is provided at the upper portion on the right end of the round hole 24b in the drawing.
Faces the opening 24c via the optical axis K and the second round hole 24
It protrudes upward in the figure from the outer peripheral portion of b. At this time, the inverted L-shaped protruding piece 24d has a shape in which the L shape is inverted, and is formed with substantially the same length as the opening 24c in the longitudinal direction. Accordingly, the second round hole sandwiched between the outer peripheral portion of the first round hole 24a of the middle lens barrel 24 and the inverted L-shaped protruding piece 24d formed to protrude above the right end of the second round hole 24b in the drawing. A concave recess 24e is formed at a position lower in height than the inverted L-shaped projecting piece 24d in the outer peripheral portion of the upper part of the drawing 24b.

A first round hole 24 formed in the middle lens barrel 24 is provided.
a and a first lens frame 41 in which a variable power lens (group) 40 is fitted in the second round hole 24b along the two long guide shafts 90 (only one is shown on one side) in the optical axis direction. It is movable. At this time, the two guide shafts 90
Keeps an axial distance between the front lens barrel 23 in which the front lens (group) 30 is fitted and the imaging element holder 83 to which the imaging element 82 is attached, passing through the middle lens barrel 24. In this state, it is horizontally mounted parallel to the optical axis K, and is also used for a second lens frame 71 in which a focus lens (group) 70 described below is fitted.

The rear lens barrel 25 faces and is symmetrical with an opening 24c opened at the lower right part of the middle lens barrel 24 in the figure and an inverted L-shaped projecting piece 24d formed at the upper right part of the figure. The opening 25a and the inverted L-shaped protruding piece 25b are formed with a small length in the longitudinal direction, and subsequently, a small first round hole 25c is formed with a small length in the longitudinal direction. A second round hole 25d having a diameter larger than the first round hole 25c is formed following the first round hole 25c.

A fixed master lens (group) 60 is fitted into the first round hole 25c of the rear lens barrel 25, and a focus lens (group) 70 is further fitted into the second round hole 25d formed on the image sensor 82 side. The second lens frame 71 in which is fitted is shared by the two long guide shafts 90 and is provided movably in the optical axis direction.

When the above-described members are assembled in the direction of the arrow, particularly when the middle lens barrel 24 and the rear lens barrel 25 are joined, the lower part of the drawing is partially opened at the joint between the two lens barrels 24, 25. The iris assembly 5 having the same configuration as that described with respect to the conventional lens barrel 10A from the opened openings 24c and 25a.
5 by inserting the upper end portion of the bracket 57 provided in FIG.
While making the iris 50 coincide with the optical axis K, the iris motor 56 is exposed outside the outer peripheral portion of the rear lens barrel 25,
In addition, the upper end portion of the bracket 57 in the figure is connected to the two lens barrels
5 is accommodated in the inverted L-shaped projecting pieces 24d and 25b protruding to the upper part in the drawing, so that the concave part 24e formed in the upper outer peripheral part of the second round hole 24b of the middle barrel 24 in the drawing. Is located at a position lower in height than the inverted L-shaped projecting pieces 24d, 25b.
A variable magnification lens motor assembly 45 having the same configuration as described in FIG.
And the focus lens motor assembly 75, the lens barrel 10B is attached to the lens barrel 1 described above.
The structure is smaller and lighter than OA.

Next, in the conventional lens barrels 10A and 10B shown in FIGS. 2 and 3, a first lens frame 41 in which a variable power lens (group) 40 is fitted and a focus lens (group) 70 are fitted. A conventional mechanism for movably guiding the inserted second lens frame 71 in the optical axis direction will be described with reference to FIGS.

FIG. 4 moves the first lens frame in which the variable power lens (group) shown in FIGS. 2 and 3 is fitted and the second lens frame in which the focus lens (group) is fitted, in the optical axis direction. It is a perspective view for explaining an example of the conventional mechanism which guides freely, (A) shows the state where the 1st and 2nd lens frames are separated, and (B) shows the 1st and 2nd lens frames. FIG. 5 shows a state in which the lenses are approaching each other. FIG. 5 shows a first lens frame in which the variable power lens (group) shown in FIGS. 2 and 3 is fitted, and a second lens in which the focus lens (group) is fitted. It is a perspective view for explaining other examples of the conventional mechanism which guides a frame movably in the direction of an optical axis, (A) shows a state where the 1st and 2nd lens frames are separated, and (B) FIG. 4 is a diagram showing a state in which first and second lens frames are approaching each other.

As shown in FIG. 4A, an optical axis includes a first lens frame 41 in which a variable power lens (group) 40 is fitted and a second lens frame 71 in which a focus lens (group) 70 is fitted. The two guide shafts 90 that guide the first and second lens frames 41 and 71 when movably guided in the directions are long rods.

First, the first lens frame 41 into which the variable power lens (group) 40 is fitted is formed at one end on the near side in the drawing by passing through a round hole having substantially the same diameter as the guide shaft 90 and has a fitting length. L =
The bearing portion 41a having L1 is connected to the guide shaft 9 on the front side.
0 and has a loose fitting gap in the direction of adjusting the distance between the two guide shafts 90 (depth direction) at the other end in the depth direction of the drawing via the variable power lens 40. The first lens frame 41 has two guide shafts 90 since the free fitting bearing portion 41b having a short fitting length of the rectangular hole is slidably and loosely fitted on the guide shaft 90 on the rear side. Can reciprocate smoothly along.

On the other hand, the second lens frame 71 in which the focus lens (group) 70 is fitted has a loose fitting gap at one end on the near side in the drawing in the direction of adjusting the distance between the two guide shafts 90 (the depth direction). A loose fitting bearing 71a having a rectangular hole having a short fitting length and a rectangular hole having a short fitting length is slidably and loosely fitted on the guide shaft 90 on the front side, and is further provided with a focus lens 70 at the back of the drawing. A round hole having substantially the same diameter as the guide shaft 90 is formed at the end side so as to form a fitting length L = L1.
The second lens frame 71 can smoothly reciprocate along the two guide shafts 90 because the bearing portion 71b having the above-mentioned structure is slidably fitted to the guide shaft 90 on the back side.

Therefore, according to the above structure, the first and second
The lens frames 41 and 71 have support structures for the two guide shafts 90 symmetrical with respect to the optical axis K at the front of the paper and at the back of the paper, and the first and second lens frames 41 and 71 are provided.
Length L of the bearing portions 41a and 71b respectively formed on
L1 indicates that when the first and second lens frames 41 and 71 approach each other on the two guide shafts 90 as shown in FIG.
b, 71a.

At this time, by setting the fitting length L of the bearing portions 41a, 71b formed on the first and second lens frames 41, 71 as long as possible, the first and second lens frames 4 are formed.
Since the backlash of the lens frames 41 and 71 on the guide shaft 90 is suppressed and the tilting of the two lens frames 41 and 71 is reduced, the perpendicularity of the two lens frames 41 and 71 to the optical axis K is good, and it is easy to set the optical axis. Become.

Therefore, the fitting length L of the bearing portions 41a, 71b of the first and second lens frames 41, 71 is set to a length L2 (L2> L1) to the extent indicated by the dotted line in FIG. Although it is sufficient to extend the length, this structure cannot be extended as it is because the above-described interference occurs.

In order to improve this, FIG.
As shown in (B), by using the four guide shafts 90, the bearing portions 41a and 71b and the free-fit bearing portions 41b and 7 formed on the first and second lens frames 41 and 71, respectively.
1a can slide on each guide shaft 90 independently, so that interference at the guide shaft 90 does not occur, so that the bearing portions 41a, 71 formed on the first and second lens frames 41, 71 are fitted. Although the combined length L can be set to be as long as the length L2, the number of the guide shafts 90 is doubled, which not only increases the cost but also requires a storage space for the four guide shafts 90, so that the size and weight are reduced. However, the structure cannot be achieved.

[0037]

As described above, in the example of the conventional lens barrel 10A shown in FIG. 2, the barrel 20A is divided into a front barrel 21 and a rear barrel 22. Although the number of parts is small, it is possible to reduce the cost including the mold cost and the manufacturing cost of the two lens barrels 21 and 22, but the lens barrel 10A cannot be reduced in size and weight for the above-mentioned reason, and is improved. For this reason, in another example of the conventional lens barrel 10B shown in FIG. 3, the barrel 20B is divided into a front barrel 23, a middle barrel 24, and a rear barrel 25, and An inverted L-shaped protruding piece 24 is provided at an upper portion of the drawing of the joint portion with the rear lens barrel 25.
d, 25b are made to protrude higher than the outer peripheral portion of the middle lens barrel 24, and a concave portion 24e formed in a concave shape at the upper outer portion of the middle lens barrel 24 in the figure is formed by an inverted L-shaped projecting piece of the two lens tubes 24, 25 The variable magnification lens motor assembly 45 and the focus lens motor assembly 75 are positioned at a position lower than the heights 24d and 25b and along the concave portion 24e of the middle lens barrel 24.
By mounting the lens barrel 10B, the size and weight of the lens barrel 10B can be reduced, but by increasing the number of parts of the lens barrel 20B by one, the mold cost and the manufacturing cost of each of the lens barrels 23 to 25 are included. Cost increases, and each lens barrel 23-
Each lens (group) 40, 50, 60,
There is a problem in that the accuracy of optical axis alignment between the 70s is reduced.

Therefore, a lens barrel which is small and light even in a structure in which the lens barrel is divided into two along the length direction is desired, and furthermore, bearing portions formed on the first and second lens frames respectively. There is a demand for a lens barrel having a structure in which the number of guide shafts becomes an optimum number when the fitting length L is set as long as possible.

[0039]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and a first invention is directed to a front lens barrel in which a front lens (group) is fitted, and the front lens (group). ), A variable-magnification lens (group) movable in the optical axis direction to zoom (zoom) a subject image, an iris that can be opened and closed to adjust the amount of light of the subject image, and a fixed master lens ( Group) and a focus lens (group) movable in the optical axis direction in order to adjust the focus of the subject image in cooperation with the fixed master lens (group). In a lens barrel constituted by dividing a lens barrel into two along a length direction, a motor assembly for a variable power lens, wherein a motor for driving the variable power lens (group) is mounted on a bracket, and the focus lens Mode to drive (group) When attaching the iris and a motor for opening and closing the iris to the outer peripheral portion of the rear lens barrel, the rear lens barrel An opening is formed in a part of the outer peripheral portion of the iris assembly, and an inverted concave projecting portion facing the opening via the optical axis is formed so as to protrude from the outer peripheral portion of the rear barrel. Inserting the end of the bracket through the opening to align the iris with the optical axis and to store the end of the bracket in the inverted concave projection; At least one of the variable-magnification lens motor assembly and the focus lens motor assembly is attached along an outer peripheral portion of the lower lens barrel having a smaller height. A lens barrel.

According to a second aspect of the present invention, in the lens barrel according to the first aspect of the present invention, an outer peripheral portion of the rear barrel, which is lower in height than the inverted concave projection, is provided with the variable magnification motor. A lens barrel characterized in that an undercut is made in an R shape from the center of each of the motors attached to the assembly and the motor assembly for the focus lens to a radius slightly larger than the radius of each motor.

A third invention is a zoom lens (group).
And a focus lens (group) movably housed in the lens barrel, wherein the variable power lens (group) is fitted,
And a bearing portion having a fitting length of a predetermined length at one end side, and a short fitting length between the one end side and the other end side via the variable power lens (group) for adjusting a distance between axes. A first lens frame having a free-fit bearing portion, and the focus lens (group)
And a fitting portion having a fitting length of a predetermined length on one end side, and a short fitting length between the one end side and the other end side via the focus lens (group) and adjusting a distance between axes. A second lens frame formed with a free-fitting bearing portion, and the optical axis of the variable power lens (group) and the focus lens (group). Two attached long guide shafts, and a predetermined distance from one of the two long guide shafts, which is transversely parallel to the optical axis and is one of the two long guide shafts. A short guide shaft attached separately, and each bearing formed on the first and second lens frames is separately fitted to one and the other of the two long guide shafts. And the loose fitting bearings formed on the first and second lens frames. One of the two elongated guide shafts is loosely fitted to one of the two long guide shafts, and the other loosely fitted bearing portion is loosely fitted to one of the short guide shafts. Lens barrel.

[0042]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a lens barrel according to the present invention will be described below in detail with reference to FIGS.

FIG. 6 shows a lens barrel according to the present invention.
FIG. 7 is an exploded view showing a structure when the lens barrel is divided into two along the length direction, and FIG. 7 is a view for explaining an operation of molding the rear lens barrel shown in FIG. 6 using a molding die. FIG. 8 is a perspective view showing a state in which an iris assembly is attached to a rear lens barrel from below and a variable magnification lens motor assembly and a focus lens motor assembly are attached to the rear lens barrel from above in the lens barrel according to the present invention. FIG. 9 is a sectional view showing a state in which an iris assembly is mounted in an opening of a rear lens barrel and an inverted concave projection in a lens barrel according to the present invention, and FIG. 10 is a lens barrel according to the present invention. 5 is a cross-sectional view showing a state in which a motor assembly for a variable power lens and a motor assembly for a focus lens are attached to a concave recess formed in an outer peripheral portion of a second round hole of the rear barrel in the upper part of the figure.

For convenience of explanation, the same reference numerals are given to the same constituent members as those shown in the conventional example, and new reference numerals are given to the constituent members different from the conventional example. I will explain.

As shown in FIG. 6, in the lens barrel 10C according to the present invention, the barrel 20C is moved along the longitudinal direction of the front barrel 2C.
6 and a rear lens barrel 27.
27 is mass-produced by a molding die using a resin material or a die-cast material.

The front lens barrel 26 has a front lens (group) 30 fitted in a round hole 26a formed along the optical axis K.

In the rear lens barrel 27, a large first round hole 27a is formed on the front lens 30 side with a small length in the longitudinal direction, and is connected to the first round hole 27a. A second round hole 27b slightly smaller in diameter than the first round hole 27a is formed in an elongated shape, and an opening 27c is formed at a lower portion on the right end of the second round hole 27b in the drawing with a slight length in the longitudinal direction. In addition, an inverted concave projection 27d is opposed to the opening 27c via the optical axis K at a position above the right end in the drawing of the second round hole 27b.
It is formed so as to protrude upward in the drawing from the outer peripheral portion of the round hole 27b. At this time, the inverted concave-shaped protrusion 27d changes the concave
The opening 27c is formed in the same shape as the opening 27c in the longitudinal direction. Thereby, the second round hole sandwiched between the outer peripheral portion of the first round hole 27a of the rear barrel 27 and the inverted concave-shaped protrusion 27d formed to protrude above the right end of the second round hole 27b in the drawing. A concave concave portion 27e is provided on an outer peripheral portion of the upper portion of the drawing 27b in the drawing.
It is formed at a position lower than d.

An opening 27c formed in the rear lens barrel 27 is provided.
A small third round hole 27f is formed at an intermediate portion following the inverted concave projection 27d with a small length in the longitudinal direction, and further following the third round hole 27f. 27f
A larger-diameter fourth round hole 27g is formed to be long.

Here, when the rear barrel 27, which forms a part of the essential part of the present invention, is molded using a molding die, the rear barrel 27 is formed.
The opening 27c and the inverted concave projection 27d formed at the lower right and upper right portions of the second round hole 27b in the drawing are used to connect the slide molding die SK and the hole molding die AK as shown in FIG. Molded using.

That is, the slide molding die SK is provided with the rear barrel 2
7, a hole H having substantially the same diameter as the third small round hole 27f formed in the middle portion of the rear lens barrel 2 is formed.
7 is formed in accordance with the opening size of the opening 27c partially opened in the outer peripheral portion, and the upper portion is formed so as to reach the inside of the inverted concave projection 27d formed in the outer peripheral portion of the rear lens barrel 27. ing.

On the other hand, the hole forming die AK includes a first round hole 27a, a second round hole 27b, and a third round hole 2b formed in the rear barrel 27.
The shaft portions J1 to J3 are formed in a stepped cylindrical shape so as to obtain 7f.

When the two molds SK and AK are inserted into a molding machine (not shown), the slide molding die SK is inserted in the direction of arrow Y1 in the first step, and then the hole forming die SK is inserted in the second step. The molding die AK is inserted in the direction of the arrow X1, and the shaft J3 of the hole molding die AK is passed through the hole H of the slide molding die SK. Thereafter, the resin material or the die casting is performed in the molding machine. The rear lens barrel 27 is formed using a material or the like. Furthermore,
When pulling out both molds SK and AK from the molding machine,
In a step, the hole forming die AK is pulled out in the direction of the arrow X2, and then in a fourth step, the slide forming die SK is pulled out in the direction of the arrow Y2, whereby the second round hole 2 of the rear barrel 27 is pulled out.
An opening 27c and an inverted concave projection 27d are formed at lower and upper portions of the right end of FIG. 7b, respectively.

Referring back to FIG. 6, a first lens frame 41 in which a variable power lens (group) 40 is fitted is provided in the first round hole 27a and the second round hole 27b formed in front of the rear lens barrel 27. It is movable in the optical axis direction along two long guide shafts 90 (only one guide shaft is shown on one side). At this time, the two guide shafts 90 pass through the outside of the third round hole 27f, and the front lens barrel 26 in which the front lens (group) 30 is fitted, and the imaging element holder 83 to which the imaging element 82 is attached, and Between the two guide shafts 90 in parallel with the optical axis K while maintaining the distance between the axes before and after the plane of the drawing.
Among them, the guide shaft 90 on the back side is also used for a second lens frame 71 in which a focus lens (group) 70 described below is fitted.

A fixed master lens (group) 60 is fitted in a third round hole 27f formed in an intermediate portion of the rear lens barrel 27, and a fourth round hole 27 formed in the image pickup device 82 side.
g, the second lens frame 71 in which the focus lens (group) 70 is fitted is a long guide shaft 90 on the back side.
And is movably provided in the optical axis direction along a short guide shaft 91 newly provided on the near side as described later.

When assembling the above-described members from the direction of the arrow, as shown in FIG. 8, the iris assembly having the same configuration as that of the conventional lens barrels 10A and 10B is particularly mounted on the rear barrel 27 from below. 55, a variable magnification lens motor assembly 45 and a focus lens motor assembly 75 having the same configuration as described in the conventional lens barrels 10A and 10B are mounted from above.

As shown in FIGS. 6 and 9, the iris assembly 55 described above is configured such that the lower part of the right end of the second round hole 27b of the rear lens barrel 27 is opened from the opening 27c to the upper end of the bracket 57 as shown in FIG. The iris 50 is aligned with the optical axis K, the iris motor 56 is exposed outside the outer peripheral portion of the rear lens barrel 27, and the upper end of the bracket 57 in the drawing is the Inverted concave projection 27d protruding from the upper right part of the two round holes 27b in the figure.
Is housed inside.

Further, the above-described motor assembly 45 for the variable power lens and the motor assembly 75 for the focus lens are arranged as shown in FIG.
And as shown in FIG. 10, the second round hole 27b of the rear lens barrel 27.
Is attached to the upper left and right sides of the concave recess 27e formed in the outer peripheral portion in the upper part of the figure. At this time, the concave concave portion 27e formed on the outer periphery of the rear lens barrel 27 has a radius slightly larger than the radius of both the motors 46 and 76 from the center of the variable magnification lens motor 46 and the focus lens motor 76 mounted on the upper left and right sides. R portion 27e with undercut in R shape
The first and second 27e2 are each formed with a cutout.
Therefore, these R portions 27e1 and 27e2 are connected to the rear lens barrel 2
7 is located at a position lower than the inverted concave projection 27d protruding above the right end of the second round hole 27b in the drawing, so that the variable magnification lens motor assembly 45 and the focus lens motor assembly Since the solid 75 approaches the optical axis K, it is possible to reduce the size and weight.

In the embodiment, the motor assembly 45 for the variable power lens and the motor assembly 75 for the focus lens are described as being attached to the upper part of the outer periphery of the rear lens barrel 27. One may be attached.

In the embodiment, the rear barrel 27 has a large first round hole 27a formed in the front lens 30 side with a small length in the longitudinal direction. Subsequently, a second round hole 27b slightly smaller in diameter than the first round hole 27a is formed to be long, and further, an inverted concave-shaped protruding portion 27d is formed to protrude above the right end of the second round hole 27b in the drawing. , The second round hole 27b
A concave recess 27e is formed in the outer peripheral portion above the drawing, but is not limited thereto, and the first round hole 27a and the second round hole 2e are formed.
7b is formed in a long shape with a round hole having the same diameter, and an inverted concave-shaped protruding portion 27d is formed so as to protrude at a position above the right end of the round hole. Even if it is formed at a position lower than the portion 27d and the motor assembly 45 for the variable power lens and the motor assembly 75 for the focus lens are attached thereto, the size and weight can be reduced.

Therefore, even if the lens barrel 20C is divided into a front lens barrel 26 and a rear lens barrel 27 along the longitudinal direction, the lens barrel 1
0C can be reduced in size and weight, and the molding die is also less expensive than the three-part structure described in the other examples of the conventional lens barrel 10B.

Next, in the lens barrel 10C according to the present invention shown in FIG. 6, the first lens frame 41 in which the variable power lens (group) 40 is fitted, and the first lens frame 41 in which the focus lens (group) 70 is fitted. A mechanism for guiding the two lens frames 71 so as to be movable in the optical axis direction will be described with reference to FIGS.

FIG. 11 shows, in a lens barrel according to the present invention, a first lens frame fitted with a variable power lens (group) and a second lens frame fitted with a focus lens (group) in the optical axis direction. It is a perspective view for explaining the mechanism which guides freely, (A) shows the state where the 1st and 2nd lens frames are separated, and (B) shows the 1st and 2nd lens frames approaching each other. FIGS. 12A and 12B show a first lens frame in which a variable power lens (group) is fitted, and FIG. 12B shows a focus lens (group) in the lens barrel according to the present invention. FIG. 6 is a front view showing a second lens frame in which is fitted.

As shown in FIG. 11A, a first lens frame 41 in which a variable power lens (group) 40 is fitted, and a second lens frame 71 in which a focus lens (group) 70 is fitted, have an optical axis. When the first lens frame 41 is guided to be movable in the
The two guide shafts 90 that guide the second lens frame 71 use a long round bar, and the two guide shafts 90 and 91 that guide the second lens frame 71 share one of the above-described guide shafts 90, and the other one. A short round bar newly provided in the book is used.

First, the first lens frame 41 in which the variable power lens (group) 40 is fitted is formed through a circular hole having substantially the same diameter as the guide shaft 90 at one end on the near side in the drawing, and has a predetermined length. A bearing portion 41a having a fitting length L = L2 (L2 is longer than L1 described in the conventional example) is slidably fitted to the guide shaft 90 on the near side, and the variable power lens 40 A rectangular hole having a loose fitting gap is formed on the other end side of the illustrated rear side in the direction of adjusting the distance between the two guide shafts 90 (depth direction), and the fitting length of the rectangular hole is short. Since the fitting bearing portion 41b is loosely slidably fitted to the guide shaft 90 on the rear side, the first lens frame 41
It can smoothly reciprocate along the guide shaft 90 of the book. The front view in this case is as shown in FIG.

On the other hand, the second lens frame 71 in which the focus lens (group) 70 is fitted has a loose fitting gap at one end on the near side in the drawing in the direction for adjusting the distance between the two guide shafts 90 (the depth direction). Is formed, and the loosely-fitting bearing portion 71a having a short fitting length of the rectangular hole is slidably fitted to the newly provided short guide shaft 91 one step lower than the guide shaft 90 on the near side. At the same time, a round hole having substantially the same diameter as the guide shaft 90 is formed at the other end side in the back of the drawing via the focus lens 70 to form a predetermined fitting length L = L2 (where L2 is a conventional length). Since the bearing 71b having a length longer than L1 described in the example) is slidably fitted to the guide shaft 90 on the back side, the second
The lens frame 71 can smoothly reciprocate along the two guide shafts 90. The front view in this case is shown in FIG.
(B).

At this time, the short guide shaft 91 newly provided on the front side is provided between the side wall of the third round hole 27f (FIG. 6) of the rear lens barrel 27 and the imaging element holder 83b (FIG. 6). At a position parallel to the optical axis K. Further, the short guide shaft 91 in which the loose fitting bearing portion 71a of the second lens frame 71 is loosely fitted interferes with the long guide shaft 90 on the front side in which the bearing portion 41a of the first lens frame 41 is fitted. In order to avoid such a situation, in the figure, since they are attached at a predetermined distance in the height direction, as shown in FIG.
Even if the second lens frames 41 and 71 approach each other, they do not interfere with each other.

In the embodiment, the loose fitting bearing portion 71a of the second lens frame 71 is loosely fitted to the short guide shaft 91. However, the present invention is not limited to this. 41b is loosely fitted to the short guide shaft 91,
In addition, a structure may be employed in which the loose-fit bearing portion 71a of the second lens frame 71 is fitted to the long guide shaft 90.

Therefore, according to the above structure, the first and second
When the fitting length L of the bearing portion 71b of the lens frames 41 and 71 is set to a long length L2, two long guide shafts 9
0 and one short guide shaft 91, the first and second lens frames 41 and 71 can reciprocate without interfering with each other.
Since the backlash on the first guide shafts 90 and 91 is suppressed and the two lens frames 41 and 71 are less inclined, the perpendicularity of the two lens frames 41 and 71 with respect to the optical axis K is good and the optical axis can be easily set. Become.

[0069]

According to the lens barrel according to the present invention described in detail above, according to the lens barrel according to the first and second aspects, the lens barrel is connected to the front barrel and the rear barrel along the length direction. In particular, when the lens is divided into two parts, an opening is formed in a part of the outer peripheral part of the rear lens barrel, and the inverted concave-shaped protrusion which is opposed to the opening via the optical axis is formed in the rear mirror. Protruding from the outer peripheral part of the cylinder, inserting the end of the bracket of the iris assembly from the opening, aligning the iris with the optical axis, and storing the end of the bracket in the inverted concave projection, and further, Since at least one of the zoom lens motor assembly and the focus lens motor assembly is attached along the outer peripheral portion of the rear lens barrel having a height lower than the inverted concave projection, the lens barrel is moved in the longitudinal direction. Even if it is divided into a front lens barrel and a rear lens barrel along It is possible to reduce the capacity.

According to the lens barrel of the third aspect, when the variable power lens (group) and the focus lens (group) are movably stored in the lens barrel, the variable power lens (group) is moved. One end of the fitted first lens frame and the second lens frame fitted with the focus lens (group) are each formed with a bearing having a fitting length of a predetermined length, and are fitted on the other end. Each of the first and second lens frames is provided with one of the two long guide shafts on one and the other of the two long guide shafts. Along with separate fitting, one of the loose fitting bearings formed on the first and second lens frames is loosely fitted on one of the two long guide shafts, Since the other free-fitting bearing portion was loosely fitted on one short guide shaft, the first and second lens frames were the same. Without but which interfere even close to each other, first, for pressing the looseness on the second lens frame of the guide shaft inclination of both lens frame is reduced,
The perpendicularity of both lens frames to the optical axis becomes good, and the optical axis can be easily set.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing a general lens barrel.

FIG. 2 is an exploded view showing a structure of an example of a conventional lens barrel when the lens barrel is divided into two along a length direction.

FIG. 3 is an exploded view showing a structure of another example of a conventional lens barrel when the lens barrel is divided into two along the length direction.

FIG. 4 shows a first lens frame in which the variable power lens (group) shown in FIGS. 2 and 3 is fitted and a second lens frame in which the focus lens (group) is fitted so as to be movable in the optical axis direction. It is a perspective view for explaining an example of the conventional mechanism which guides.

FIG. 5 shows a first lens frame in which the variable power lens (group) shown in FIGS. 2 and 3 is fitted and a second lens frame in which the focus lens (group) is fitted so as to be movable in the optical axis direction. It is a perspective view for explaining other examples of the conventional mechanism which guides.

FIG. 6 is an exploded view showing a structure in a case where the lens barrel according to the present invention is divided into two along the length direction of the barrel.

FIG. 7 is a view for explaining an operation of molding the rear lens barrel shown in FIG. 6 using a molding die.

FIG. 8 is a perspective view showing a state in which an iris assembly is attached to a rear lens barrel from below and a variable-magnification lens motor assembly and a focus lens motor assembly are attached to the rear lens barrel from above in the lens barrel according to the present invention; FIG.

FIG. 9 is a cross-sectional view showing a state in which an iris assembly is mounted in the opening of the rear barrel and the inverted concave projection in the lens barrel according to the present invention.

FIG. 10 shows a lens barrel according to the present invention, in which a motor assembly for a variable power lens and a motor assembly for a focus lens are mounted in a concave concave portion formed in an outer peripheral portion of the second round hole of the rear lens barrel above the drawing. FIG. 4 is a cross-sectional view showing a state in which the state of FIG.

FIG. 11 shows a lens barrel according to the present invention, in which a first lens frame fitted with a variable power lens (group) and a second lens frame fitted with a focus lens (group) are movable in the optical axis direction. FIG. 2 is a perspective view for explaining a mechanism for guiding
(A) shows a state in which the first and second lens frames are separated from each other, and (B) shows a state in which the first and second lens frames are close to each other.

FIGS. 12A and 12B show a lens barrel according to the present invention, in which FIG. 12A shows a first lens frame fitted with a variable power lens (group), and FIG.
FIG. 3 is a front view showing a second lens frame in which a focus lens (group) is fitted.

[Explanation of symbols]

 10C: Lens barrel according to the present invention 20C: Lens barrel 26: Front lens barrel 27: Rear lens barrel 27a: First round hole 27b: Second round hole 27c: Opening 27d: Reverse concave projection 27e: Recess 27f Third round hole 27g Fourth round hole 30 Front lens 40 Variable power lens 41 First lens frame 41a Bearing 41b Free-fit bearing 45 Motor assembly for variable power lens 46 Variable Double lens motor 47 ... Warm 48 ... Bracket 50 ... Iris 55 ... Iris assembly 56 ... Iris motor 57 ... Bracket 60 ... Fixed master lens 70 ... Focus lens 71 ... Second lens frame 71a ... Free-fit bearing 71b ... Bearing Part 75: Focus lens motor assembly 76: Focus lens motor 77: Worm 78 ... Bracket 82: Image sensor 83: Image sensor holder 90: long guide shaft 91: short guide shaft

Claims (3)

[The claims] 1. A front lens barrel fitted with a front lens (group), and a variable magnification movable in an optical axis direction for zooming a subject image photographed by the front lens (group). A lens (group), an iris that can be opened and closed to adjust the amount of light of the subject image, a fixed master lens (group), and the focus of the subject image is adjusted in cooperation with the fixed master lens (group). And a focus lens (group) that is movable in the optical axis direction, and a lens barrel formed by dividing the lens barrel into two along the length direction. A motor assembly for a variable power lens in which a motor for driving the (group) is mounted on a bracket, a motor assembly for a focus lens in which a motor for driving the focus lens (group) is mounted on a bracket,
When attaching the iris and an iris assembly in which a motor for opening and closing the iris is attached to a bracket to an outer peripheral portion of the rear barrel, an opening is formed in a part of an outer peripheral portion of the rear barrel, and An inverted concave-shaped protruding portion facing the opening via the optical axis is formed so as to protrude from an outer peripheral portion of the rear lens barrel, and an end of the bracket of the iris assembly is inserted from the opening. Aligning the iris with the optical axis and storing the end of the bracket in the inverted concave projection; and furthermore, in the outer peripheral portion of the rear lens barrel having a height lower than the inverted concave projection. A lens barrel to which at least one of the variable-magnification lens motor assembly and the focus lens motor assembly is attached along. 2. The lens barrel according to claim 1, wherein an outer peripheral portion of the rear barrel, which is lower in height than the inverted concave projection, is provided with the variable magnification lens motor assembly and the focus lens motor. A lens barrel having an R-shaped undercut with a radius slightly larger than the radius of each motor from the center of each motor attached to the assembly. 3. A lens barrel in which a variable power lens (group) and a focus lens (group) are movably housed, wherein the variable power lens (group) is fitted, and a predetermined length is fitted on one end side. A first bearing portion having a combined length, and a free-fitting bearing portion having a short fitting length and adjusting a distance between axes is formed at the one end side and the other end side via the variable power lens (group). A lens frame, a bearing part fitted with the focus lens (group), and having a fitting length of a predetermined length on one end side, and fitted on the other end side via the one end side and the focus lens (group) A second lens frame having a short length and a loose fitting portion for adjusting an inter-axis distance, the variable power lens (group) and the focus lens (group);
Two elongate guide shafts mounted in parallel with respect to the optical axis, and attached at a distance from each other; and One short guide shaft attached to one of the long guide shafts at a predetermined distance, and each bearing formed on the first and second lens frames is provided. The two long guide shafts are separately fitted to one and the other, and one of the two free-fit bearings formed on the first and second lens frames has two free-fit bearings. A lens barrel, wherein one of the long guide shafts is loosely fitted and the other loosely fitted bearing portion is loosely fitted to one of the short guide shafts.