JPH03150512A - Lens barrel - Google Patents

Abstract

PURPOSE:To reduce the cost by arranging and fixing a flat plate type substrate where electric accessory components in a 1st space and arranging a guide rod and a driving means in a 2nd space. CONSTITUTION:An electric accessory member 7 is held in part of the space formed between an external barrel 6 and a lens holding frame 4 by a mount 1 and a fixation member 5 without impeding the movement of the lens holding frame 4. Then two rod type lens holding frame guide members 2 and 3 are provided and the guide member 2 serves as a driving mechanism for linear extension. The guide member 3 is held in parallel to the optical axis and engages the cut 4b of the lens holding frame 4 slidably. Therefore, a device which extends a photography optical system out linearly and the flat plate type substrate where the electric accessory member 7 is mounted can be ar ranged in the mutually opposite spaces, so the outward appearance can be made small. Further, a low-cost hard circuit board is usable as the electric accessory member 7. Consequently, the cost is reducible.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a lens barrel incorporating an electrical component.

[Prior Art] In recent years, electronic cameras, video cameras, and the like have come to be equipped with actuators and various sensors for autofocus driving, aperture driving, etc., as they become more automated and electronic.

When various functions are added in this way, the amount of information transmitted between the lens side and the camera body side increases, but it is important to simplify the mechanism and develop systems such as interchangeable lenses and various parts. For this purpose, it is required to change the mechanical part of the information transmission mechanism between the lens and the camera body to an electrical connection as much as possible. For this reason, actuators and various sensors are built into the lens, and necessary electrical circuits are mounted inside the lens barrel.

A conventional example of such a lens barrel is the
There is a lens barrel for an electronic camera shown in No. 1-21176. In this example, a flexible circuit board is used as the electric circuit, and is mounted by wrapping it around the outer periphery of the portion of the lens fixing frame that is inserted into the camera body.

Another conventional example, as shown in Fig. 9, is to provide a mounting space outside the cylinder of the lens barrel in a bulging shape, and place a rigid flat plate such as a printed circuit board therein. Some are mounted with a shaped circuit board (hereinafter simply referred to as a rigid circuit board).

To briefly explain the configuration example shown in FIG. 9, the figure shows a cross-sectional view of rice grains when a lens barrel formed as a video camera is viewed from the camera side.

In this figure, 27 is the lens L4 closest to the camera side.
This lens holding frame 27 is provided with a sleeve 27a and a notch 27b.
7b is engaged with a guide member 25 that guides the movement of the lens holding frame parallel to the photographing optical axis, and a sleeve 278
A guide member 26 similar to the guide member 25 described above passes through.

These guide members 25 and 26 are each fixed to a fixed part of the lens barrel, and the lens holding frame 27 is guided by these guide members and slides, and is capable of eight movements in the optical axis direction, but perpendicular to the optical axis. Rotation is not possible within this plane.

Further, a cam barrel 28 is fitted inside the fixed barrel 30 fixed to the lens barrel, and when the cam barrel 28 rotates, the rollers 29 provided on the outer periphery of the lens holding frame 27 are rotated. A predetermined focusing operation is performed by moving the lens holding frame 27 in the optical axis direction guided by a cam groove 28a provided in the cam cylinder 28.

Furthermore, an electrical component 31 such as a hard circuit board is fixed to a part of the outer circumference of the fixed tube 30 with screws, etc., and an outer tube 32 is attached to cover this electrical component 31 and the fixed tube 30. The portion covering the electrical component 31 has a shape in which the outer cylinder protrudes outward.

[Problem to be solved by the invention] However, regarding the above-mentioned conventional example, for example,
Since the lens barrel of No. 176 uses a flexible circuit board, it has the disadvantage that it is extremely costly compared to the case where a rigid circuit board is used. Furthermore, when mounting the flexible circuit board, the flexible circuit board is wrapped around the outer periphery of the lens fixing frame and attached.
The disadvantage is that the assembly work is complicated.

In addition, in the example shown in FIG. 9 above, it is impossible to arrange a hard circuit board inside the cam tube that is the feeding device for the lens holding frame 27 because of interference with the cam tube, so there is no space for mounting the circuit board. must be provided on the outer periphery of the fixed barrel, which poses the problem of increasing the external size of the lens barrel.

Furthermore, due to this mounting space, a part of the normally cylindrical lens barrel protrudes outward in a knob-like manner, which is inconvenient to operate and is also undesirable in terms of appearance. .

The present invention has been made in order to solve the problems of these conventional devices, and its purpose is to solve the problems of the conventional lens barrel as described above, and to increase the size of the lens barrel without increasing its external size. To provide a structurally simple and inexpensive lens barrel in which electrical components can be mounted.

[Means for Solving the Problems] The features of the present invention for achieving the above object include a plurality of guide rods extending in the optical axis direction inside a cylindrical outer cylinder, and a light A lens barrel including a photographing optical system supported such that movement in the axial direction is permitted but rotation about the optical axis is prevented, and a driving means for moving the photographing optical system in the optical axis direction, A plane parallel to the optical axis and parallel to the chord direction of the outer cylinder divides the space inside the outer cylinder into two in the radial direction, and a space on the opposite side of the optical axis divided by the plane is divided into two parts. A flat board carrying electrical components is fixedly arranged in one space, and the guide rod, photographing optical system, and drive means are arranged in the divided second space on the optical axis side. It is in the place where it is done.

In the above, the linear feeding device for the photographing optical system, which is composed of a guide rod and a moving means, typically prevents rotation of the photographing optical system around the optical axis but allows movement in the direction of the optical axis. An example of such a structure is one in which one of the plurality of guide rods that movably supports the optical system is provided as a threaded shaft that is screwed into a nut portion formed in the photographing optical system. In this case, since the screw shaft is used as part of the guide means of the photographing optical system, this is a preferable configuration for simplifying the apparatus.

Another example of a driving means for linearly advancing the photographing optical system is realized by a configuration in which the photographing optical system is engaged with a cam plate that is swung in a plane approximately in the chordal direction of the outer cylinder. You can also do that.

[Function] According to the present invention configured as described above, the electrical components are incorporated into the lens barrel without increasing the external shape of the lens barrel, and by using an inexpensive hard circuit board. The cost of the entire lens barrel can be reduced.

[Example] The present invention will be described in detail below based on an example shown in the drawings.

Example 1 Fig. 1 is a cross-sectional view of a part of a lens barrel of an unexamined example taken perpendicular to the optical axis, Fig. 2 is a cross-sectional view in the optical axis direction along line A-A, and Fig. 3 1A and 1B respectively show cross-sectional views in the optical axis direction along line B-B in FIG.

The lens barrel of this example is characterized by employing a screw feeding mechanism as a linear feeding device for the lens holding frame, which is the photographing optical system, and by disposing a hard circuit board inside the cylindrical outer tube.

In these figures, reference numeral 6 denotes a cylindrical outer tube of a lens barrel, and a mount 1 for coupling the lens barrel to a camera body (not shown) is fixed to the end of the lens barrel on the camera side.

Reference numeral 4 denotes a lens holding frame, which holds the lens L1, has a shape like an arcuate portion cut out from a disc in this example, and has a sleeve 4a and a notch 4b penetrating in the optical axis direction. A guide member 2 (described later) passes through the notch 4b, and a guide member 3 (described later) is engaged with the notch 4b. Further, inside the sleeve 4a, there is provided a nut portion that is screwed into a threaded portion of a guide member 2, which will be described later.

The lens holding frame guide means of this example has two rod-shaped lens holding frame guide members (hereinafter referred to as guide members) 2 and 3 (the guide member 2 of this example is a linearly extending drive member). (also serves as a mechanism). That is, the guide member 2 is provided parallel to the optical axis, and its end on the camera side is held by the mount 1, and the other end is held by the fixing member 5 fixed to the outer tube 6.
is maintained.

Like the guide member 2, the guide member 3 is held parallel to the optical axis by the mount 1 and the fixing member 5, and is slidably engaged with the notch 4b of the lens holding frame 4.

Further, the guide member 2 has a threaded shaft with a threaded portion provided on its outer peripheral surface, and the nut portion of the sleeve 4a of the lens holding frame 4 is screwed onto this shaft, thereby forming a screw feeding mechanism, This screw shaft (squid guide member 2)
''), the lens holding frame is driven to extend linearly.

Therefore, in this example, the lens holding frame 4 can be moved in the optical axis direction by rotating the screw shaft 2 by a rotation drive means such as a motor (not shown).

By employing the screw feeding mechanism as described above, in this example, it is possible to arrange the electrical component inside the cylinder, which is another feature. That is, 7 is an electrical component such as a hard printed circuit board that is cheaper than a flexible circuit board, and by mounting electrical components, an electrical circuit necessary for the operation of the lens barrel is formed. In this example, the electrical component 7 is installed in a part of the space formed between the outer cylinder 6 and the lens holding frame 4 (i.e., an arcuate cutout of the lens holding frame). It is fixedly held by a mount 1 and a fixing member 5 in an arrangement that does not hinder movement.

Note that 9 is a contact member that forms a contact point for electrical communication between the camera body side and the lens barrel side, and one end of the piece 9' is electrically connected to the electrical component 7 via a flexible circuit board 8 for circuit connection, for example. Connected.

In this way, in this example, by employing a screw feeding mechanism as a linear feeding mechanism for the lens holding frame 4, the electrical component 7 such as a low-cost hard circuit board is placed between the outer cylinder 6 and the lens holding frame 4. It can be placed in a part of the formed space to improve space efficiency.

Furthermore, since the work of fixing the guide member 2 and the work of fixing the electrical component 7 can be done simultaneously during assembly, it has become possible to simplify the assembly work.

Example 2 This example is shown in FIGS. 4 to 6, where FIG. 4 is a sectional view of a part of the lens barrel of this example taken perpendicular to the optical axis, and FIG. 6 shows a cross-sectional view along the line C in the optical axis direction, and FIG. 6 shows a cross-sectional view in the optical axis direction along the line D--D in FIG. 1, respectively.

1 The feature of the lens barrel of this example is that a cam mechanism is adopted as the lens holding frame drive mechanism, and the other configurations are the same as in Example 1 above.

In these figures, 21 is the cylindrical outer tube of the lens barrel, and IO is the mount 10.

The lens holding frame guide means of this example is configured as follows. That is, 11, 12 and 13 are shaft-shaped guide members provided in the lens barrel parallel to the optical axis, respectively.
They are each fixedly held by a mount IO and a fixing member 22.

Reference numeral 14 denotes a lens holding frame, which holds the lens L2, cuts out two arcuate parts from the disc, and further supports the guide member 1.
The sleeve 14a has a shape in which a portion through which the guide member 2 passes is cut out, and the guide member 13 passes through the sleeve 14a.
A notch 14b that engages is provided.

Further, 15 is a lens holding frame that holds the lens L3, and has a similar shape except that the engagement between the lens holding frame 14 and the guide member 1213 is different, and the guide member 12 passes through the lens holding frame 15. A notch 15b with which the sleeve 2 15a and the guide member 13 engage are provided.

Note that the guide member 11 and the sleeve 14a of this example are not in a threaded engagement relationship and are adapted to slide relative to each other.

One of the features of this example is that the linear feeding mechanism of the lens holding frame is constructed of a cam mechanism that uses a flat cam plate and is installed in a part of the circumferential direction inside the cylindrical outer cylinder. be.

This cam mechanism will be explained below based on FIGS. 7 and 8.

FIG. 7 is a sectional view of the cam mechanism along the optical axis direction for explaining the cam mechanism of this example, and FIG. 8 is a plan view showing an example of a cam plate.

In this figure, reference numeral 16 denotes a cam plate holding plate, which is a part of the space formed between the inside of the outer cylinder 2 and the lens holding frames 14 and 15, and is a part of the space where the electrical components described below are arranged. are fixed to the mount 10 and the guide member holding member 22 at positions spaced apart in the circumferential direction, and are provided parallel to the optical axis.

Inside this cam plate holding plate 16, a cam plate 18 having a shape as shown in FIG. It is installed like this.

Further, the cam plate holding plate 16 is provided with a cam groove 18a and a cam groove 18b, and the roller 19 fixed to the lens holding frame 14 is provided with a cam groove 18a, and the lens holding frame 15 is provided with a cam groove 18a.
The cam groove 18b is cam-engaged with the roller 20 fixed to the roller 20.

With the cam mechanism having such a configuration, the lens holding frame can be moved by swinging the cam plate 18 around the bin 17 using a swing driving means (not shown).

The electrical component 23 in this example is a part of the space formed between the inside of the outer cylinder 21 and the lens holding frames 14 and 15, and is mounted on the mount 10 at a position that does not interfere with the swinging of the cam plate 18. It can be fixedly held by the fixing member 22.

As described above, by employing the cam mechanism for linearly extending the lens holding frames 14 and 15 in this example, it is possible to arrange the electrical component 23 such as a low-cost hard circuit board inside the circular outer cylinder. It is possible to improve space efficiency and simplify assembly work.

[Effects of the Invention] As explained above, according to the present invention, the device for linearly advancing the photographing optical system is arranged on one side (
The flat board on which electrical components are mounted can be placed in the space on the opposite side of this division.
The outer shape of the lens barrel can be made smaller than that of the conventional example, and it is also possible to prevent a part of the outer barrel from protruding outward in a knob-like manner and hindering operation.

Furthermore, since a hard circuit board, which is lower in cost than a flexible circuit board, can be used as the electrical component, the cost of the entire lens barrel can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of the lens barrel of Example 1 taken perpendicular to the optical axis, FIG. 2 is a cross-sectional view along the A-A line in the optical axis direction, and FIG. - It is a sectional view along the B line. FIG. 4 is a cross-sectional view of the lens barrel of Example 2 taken perpendicular to the optical axis, FIG. 5 is a cross-sectional view along the line C-C of the lens barrel, and FIG. - It is a sectional view along the D line. FIG. 7 is a sectional view of the cam mechanism along the optical axis direction for explaining the cam mechanism, and FIG. 8 is a plan view showing an example of a cam plate. FIG. 9 is a cross-sectional view showing an example of a conventional lens barrel. 1, lO...Mount 2.3.11.12.13...Guide member 4.14.1
5... Lens holding frame 4a, 14a, 15a, 27a - sleeve 4b
, 14b, 15b, 27b...notch 5.22...
Fixed member 6.21.32... Outer cylinder 7.23... Electrical component 8... Flexible circuit board 9.24... Contact member 18... Cam plate 18a, 18b, 28a - Cam groove 19 .20.2
9...Koro Ll, Ll, L3, L4...Lens and 4 others

Claims (1)

[Claims] 1. A plurality of guide rods extending in the optical axis direction inside the cylindrical outer cylinder, and these guide rods allow movement in the optical axis direction but prevent rotation around the optical axis. In a lens barrel including a photographing optical system supported so as to be blocked and a driving means for moving the photographing optical system in the optical axis direction, The space inside the outer cylinder is divided into two in the radial direction by a plane defined by the plane, and a flat board with electrical components mounted in the first space on the opposite side of the optical axis divided by the plane. is fixedly arranged, and the guide rod, the photographing optical system, and the driving means are arranged in the divided second space on the optical axis side. 2. In claim 1, the driving means for moving the photographing optical system in the optical axis direction is constructed by screwing a nut portion of the photographing optical system onto a rotatable screw shaft provided as one of the guide rods. A lens barrel characterized by: 3. In claim 1, the inside of the second space is further divided in the radial direction by a second plane parallel to the optical axis and in the chordal direction of the outer cylinder, and by the second plane. The guide rod and the photographing optical system are arranged in the divided space on the side of the optical axis, and the outer cylinder is swung in a plane that is approximately in the chordal direction in the space opposite to the divided optical axis. A lens barrel characterized in that a cam plate is arranged, and the cam plate and a photographing optical system are cam-engaged to constitute a means for moving the photographing optical system.