JPH10274734A - Electrical connection mechanism in lens barrel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the degree of freedom in terms of the design of a lens barrel by providing a mechanism for electrically connecting a camera main body side and a driving motor fixed in the moving frame of a lens group extended while turning in the lens barrel. SOLUTION: The 1st end and the 2nd end of the curved part 62 of a flexible flat cable are respectively fixed in the driving motor 20 and a supporting part arranged on a virtual cylindrical surface with a photographing optical axis as an axial center. The 1st end of the curved part 62 is positioned on a plane including the photographing optical axis and fixed in the motor 20 in a state where its tangential direction is in parallel with the photographing optical axis. The 2nd end is positioned on the plane orthogonal to the photographing optical axis and fixed in the supporting part in a state where its tangential direction is aligned with the tangential direction of the virtual cylindrical surface 50. The length of the curved part 62 is set nearly equal to length leading to the supporting part from the motor 20 spirally along the virtual cylindrical surface 50 in a state where the motor 20 and the supporting part are most separated in a photographing optical axis direction.

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 plurality of lens groups, and more particularly, to a lens barrel having a movable frame rotatably extended in such a barrel and a camera body. Electrical connection mechanism between them.

[0002]

2. Description of the Related Art There is known a lens barrel which includes a plurality of lens groups and performs zooming or the like by relative movement of each lens group in the optical axis direction. As a lens group in such a lens barrel, there are a lens group (hereinafter, referred to as a rotating lens group) which is extended while being rotated in the optical axis direction, and a lens group (which is straightly extended without being rotated). Less than,
Straight lens group).

On the other hand, when a drive motor for driving a shutter mechanism or an aperture mechanism is disposed in a lens barrel, this drive unit is generally fixed to a moving frame of any of the lens groups.

When the drive motor is fixed to the straight lens group, the electrical connection between the drive motor and the camera body is relatively easy. However, providing the drive motor in the rotating lens group requires a wiring system. This has not been done so far due to problems such as twisting. However, in many cases, it is preferable to fix the drive motor to the rotating lens group due to the design of the lens barrel.

In such a case, the design must be changed in order to avoid fixing the drive motor to the rotating lens group, and the degree of freedom in designing the lens barrel is limited.

[0006]

Accordingly, a technical problem to be solved by the present invention is that an electric motor and a camera body fixed to a moving frame of a lens group which is extended while being rotated in a lens barrel are electrically connected. The purpose of the present invention is to provide a mechanism for connecting the lens barrel, thereby increasing the design freedom of the lens barrel.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in order to effectively solve the above problems, and provides an electric connection mechanism having the following configuration.

That is, the electric connection mechanism of the present invention electrically connects the drive motor fixed to the lens group rotating frame and the circuit board fixed to the lens barrel body using a flexible flat cable. Connect. Then, the circuit board is further electrically connected to the camera body. Here, the “lens group rotation moving frame” is a frame that holds the rotation lens group and guides the movement of the lens group in the lens barrel, and moves integrally with the rotation lens group. It is.

The flexible flat cable includes an arch-shaped curved portion whose first end is fixed to a drive motor and whose second end is fixed to a supporting portion which is immovable with respect to the lens barrel main body. The drive motor and the support are each located on an imaginary cylindrical surface whose axis is the photographing optical axis.

[0010] The first end of the curved portion of the flexible flat cable is fixed to the drive motor with its tangential direction being parallel to the photographing optical axis and positioned in a plane including the photographing optical axis. On the other hand, the second end portion is fixed to the supporting portion with its tangential direction coinciding with the tangential direction of the virtual cylindrical surface and located in a plane perpendicular to the photographing optical axis. In a state where the drive motor and the support portion are farthest from each other in the photographing optical axis direction, the curved portion of the flexible flat cable has a length from the drive motor to the support portion spirally along the virtual cylindrical surface. Have.

In the electrical connection mechanism having the above structure, a drive motor (for example, a drive motor such as an aperture unit or a shutter unit disposed in the lens barrel) fixed to the lens group rotating frame is provided. The flexible flat cable that communicates with the side is always accommodated in a limited cylindrical area along the virtual cylindrical surface when the lens group rotation moving frame is rotated and extended. Therefore, if any cylindrical member that moves in the optical axis direction within the lens barrel is arranged along this virtual cylindrical surface, the flexible flat cable excessively contacts the cylindrical member when the lens barrel expands and contracts. And the flexible flat cable can be favorably accommodated in the lens barrel. That is, it is possible to fix the drive motor also to the lens group rotation moving frame, so that the degree of freedom in designing the lens barrel can be increased.

In the electrical connection mechanism according to the present invention, a straight portion may be provided to be continuous with the first end of the curved portion of the flexible flat cable, and the straight portion may be fixed to the drive motor. In this case, the linear portion extends in parallel with the photographing optical axis.

In this specification, "each end of the flexible flat cable is located in any plane", "the tangential direction is parallel to the photographing optical axis", and "the end of the flexible flat cable is "The tangent direction coincides with the tangential direction of the virtual cylindrical surface" is not necessarily a strict meaning, and it goes without saying that it is sufficient if they are substantial.

[0014]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a sectional view of a zoom lens barrel according to the present invention. This lens barrel has four lens groups 10
0, 200, 300, and 400, and the second lens group 20
This is a two-group focus type four-component zoom lens that performs focusing with 0. The third of this lens barrel
The lens group 300 is a rotating lens group that is extended while rotating about the optical axis during zooming.

The third lens group 300 is fixed to a third group moving frame (lens group rotating moving frame) 302 at its lens frame 301. That is, the third lens group moving frame 302 is also extended while rotating about the optical axis during zooming.
Guide pins 303 are fixed to the third group moving frame 302,
This guide pin 303 is connected to a predetermined drive mechanism.
The aperture mechanism 10 and its drive motor 20 are fixed to the third group moving frame 302.

FIG. 2 is a perspective view of the third group moving frame 302, and FIG. 3 is a side view thereof. The moving frame 302 is the third
A cylindrical member 31 for holding the lens group on the inner peripheral side, an annular base plate 32, and three legs 33 formed around the base plate 32 are provided. The guide pins 303 shown in FIG. 1 are fixed to the legs 33. In FIG. 3, illustration of the legs 33 is omitted.

The lower surface of the base plate 32 in FIG.
Is provided. A drive motor 20 for operating the aperture mechanism 10 is disposed on the upper surface of the base plate 32. The output shaft of the drive motor 20 protrudes through the through hole formed in the base plate 32 to the lower surface side where the aperture mechanism 10 is provided, and the gear 21 fixed thereto operates the aperture mechanism 10.

The drive motor 20 is electrically connected to the camera body using a flexible flat cable 60 (hereinafter, referred to as a flat cable), and operates by receiving power supply from the camera body. In FIG. 3, a part of the flat cable 60 is shown in an elongated state before being actually mounted in the lens barrel. Flat cable
60 includes a first straight portion 61, a curved portion 62, and a second straight portion 64, which, when stretched, lie entirely in one plane. The boundary between the curved portion 62 and the second straight portion 64 (that is, the end of the curved portion) is a corner portion 63. Further, the connecting portion 65 connected to the second linear portion 64 is connected to the circuit board 40 (FIG. 1) fixed to the interchangeable lens body.
Reference). The circuit board 40 is further electrically connected to the camera body by a mechanism (not shown).

The behavior of the flat cable 60 when the moving frame 302 is actually mounted in the lens barrel will be described with reference to FIG. FIGS. 4 (a-1) and (a-2) show a state where the entire lens barrel is extended, and FIGS. 4 (b-1) and (b-2) show a state where the entire lens barrel is elongated. I have. FIGS. 4 (a-1) and (b-1)
4 (a-2) and (b-2) are respectively shown in a top view, and the upward direction in FIGS. 4 (a-2) and (b-2) is the rightward direction in FIG. Matches. FIG. 5 is a side view of FIG. 4 (a-2) viewed from the direction of arrow C.

As described above, the third group moving frame 302 is configured to be pivotally extended. That is, FIG.
From the states of -1) and (b-2), the third-group moving frame 302 rotates in the direction of arrow A2 and is extended in the direction of arrow B2, as shown in FIGS. 4 (a-1) and 4 (a-2). State. Conversely, FIG.
From the states of -1) and (a-2), the moving frame 302 for the third group is rotated in the direction of arrow A1 and retracted in the direction of arrow B1, so that FIGS. 4 (b-1) and 4 (b-2). State. In FIG.
Reference numeral 401 denotes a straight guide key also shown in FIG. 1 for guiding the movement of the fourth lens group 400. Straight ahead key 4
01 is fixed to the fixed cylinder 500 at the connecting portion 402 bent at a right angle. The fixed barrel 500 is fixed immovably with respect to the interchangeable lens body.
Are also stationary with respect to the interchangeable lens body.

The first straight portion 61 of the flat cable 60 is
It is electrically connected to the side surface of the drive motor 20 while being positioned in a plane including the photographing optical axis, and rises straight upward from the base plate 32 (that is, parallel to the photographing optical axis). Note that the first straight portion 61 can be omitted. In this case, the end of the curved portion is fixed to the side surface of the motor with its tangential direction and the photographing optical axis being parallel.

4 (a-1) and 4 (a-2), in the lens barrel extended state, along the virtual cylindrical surface 50 having the photographing optical axis as the axis,
A curved portion 62 extends helically. And the curved portion 62
A corner 63 corresponding to a boundary between the second straight portion 64 and the vicinity thereof is fixed on the connecting portion 402 of the straight guide key 401 using a fixing means such as a double-sided tape. Connection 402
Is an elongated plate-shaped member, which is located in a plane orthogonal to the photographing optical axis. Therefore, this connection
The corner portion (end of the curved portion) fixed on 402 is also located in a plane orthogonal to the imaging optical axis. That is,
The connecting portion 402 functions as a supporting portion for the corner portion 63 and the second straight portion 64.

As can be seen from FIGS. 4 (a-1) and (b-1),
The curved portion 62 is connected to the connecting portion 40 in a state where the tangential direction of the
2Fixed on top. In the example shown,
The flat cable 60 is connected to a corner 63 at the end of the curved portion 62.
Is bent at a right angle and continues to the second straight line portion 64, but such a portion bent at a right angle is not necessarily required. The end of the curved portion 62 has its tangential direction set to the virtual cylindrical surface.
It is sufficient if the second linear portion 64 is fixed to the upper surface of the connecting portion 402 in a state where the tangent direction coincides with the tangential direction 50.
May be connected to the end of the curved portion 62 in a state of being coincident with its tangential direction. Further, in the illustrated example, the connecting portion 402 is used as a supporting portion, but the supporting portion may be any as long as it is immovable with respect to the interchangeable lens main body, and may use another lens barrel component as appropriate.

As can be seen from FIG. 4, the distal end of the connecting portion between the drive motor 20 and the straight guide key is arranged along the virtual cylindrical surface 50. In other words, even when the third group moving frame 302 is rotated and extended, the distance between the drive motor 20 and the leading end of the connecting portion from the photographing optical axis is always kept substantially equal. The length of the curved portion 62 of the flat cable 60 is such that the drive motor 20 and the distal end of the connection portion 40 are connected to the drive motor 20 on the peripheral surface of the virtual cylindrical surface 50 in a state where the end is farthest in the photographing optical axis direction. The distance is set to be approximately equal to the distance between the tip of the part and the spiral.

Therefore, when the drive motor 20 and the distal end of the connecting portion are farthest from each other in the direction of the photographing optical axis, when viewed from the direction of the optical axis, the curved portion 62 extends along the virtual cylindrical surface 50 in an arc shape. FIG. 4 (a-1)). And drive motor 2
When 0 and the tip of the connecting part are closest to each other in the optical axis direction
The curved portion 62 is folded along the virtual cylindrical surface 50, and when viewed from the optical axis direction, the curved portion 62 also extends in an arc along the virtual cylindrical surface 50 (see FIG. 4 (b-1)). ).

As described above, according to the present invention, even when the drive motor 20 is fixed to the moving frame that is rotated and fed, the flat cable 60 that connects the drive motor 20 and the camera body is always virtual. It will be accommodated in a limited cylindrical area along the cylindrical surface 50. Actually, any cylindrical member that moves in the optical axis direction in the lens barrel is disposed at the position of this virtual cylindrical surface (in the illustrated example, the moving frame 400a of the fourth lens group 400 is moved). )
When the lens barrel expands and contracts, the flat cable 60 can be prevented from excessively contacting the cylindrical member.

In the above description, the drive motor 20
Although the purpose of the present invention is to drive the aperture unit, the electrical connection mechanism of the present invention can be similarly applied to a case where another electric member needs to be fixed to the lens group rotation moving frame. Needless to say. For example, a drive motor when a shutter unit is arranged in a lens barrel, a drive motor for driving a specific lens group in conjunction with an AF mechanism, and the like can be considered.

[Brief description of the drawings]

FIG. 1 is a sectional view of a zoom lens barrel according to the present invention.

FIG. 2 is a perspective view of a third group moving frame used in the zoom lens barrel of FIG. 1;

FIG. 3 is a side view of the third group moving frame in FIG. 2;

FIG. 4 is an explanatory diagram illustrating a behavior of a flexible flat cable in the zoom lens barrel in FIG. 1;

FIG. 5 is a side view with respect to FIG. 4 (a-2).

[Explanation of symbols]

 10 Throttle mechanism 20 Drive motor 21 Gear 31 Cylindrical member 32 Base plate 33 Leg 40 Circuit board 50 Virtual cylindrical surface 60 Flexible flat cable 61 First straight section 62 Curved section 63 Corner section 64 Second straight section 65 Connection section 100, 200, 300, 400 Lens group 301 Ball frame 302 Moving frame for third lens group (lens group rotating frame) 303 Guide pin 401 Straight guide key 402 Connecting section 500 Fixed cylinder

Claims (2)

[Claims] 1. A drive motor fixed to a lens group rotation moving frame, which is disposed in a lens barrel and is rotated around an optical axis for photographing, and a circuit board fixed to a lens barrel main body. A flexible flat cable, wherein the flexible flat cable has a first end fixed to the drive motor and a second end fixed to the lens barrel main body. A drive motor and the support are respectively located on an imaginary cylindrical surface having the photographing optical axis as an axis, and a first end of the curve is provided. , The tangential direction is parallel to the imaging optical axis, and in a state that is located in a plane including the imaging optical axis,
The second end of the curved portion is fixed to the drive motor, and the second end of the curved portion has its tangential direction coincident with the tangential direction of the virtual cylindrical surface, and is positioned in a plane perpendicular to the photographing optical axis. When the drive motor and the support are farthest apart from each other in the optical axis direction, the curved portion of the flexible flat cable extends spirally from the drive motor to the support along the virtual cylindrical surface. An electrical connection mechanism having a length. 2. A curved portion of the flexible flat cable is fixed to a drive motor at a straight portion provided at a first end thereof, and the straight portion extends in parallel with a photographing optical axis. The electrical connection mechanism according to claim 1, wherein: