JP3428354B2 - Electrical connection mechanism in the lens barrel - Google Patents

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 specifically, to a moving frame of a lens group which is rotationally extended in such a lens barrel and a camera body side. Between the electrical connection mechanism between.

[0002]

2. Description of the Related Art There is known a lens barrel which is composed of a plurality of lens groups and which performs zooming or the like by relatively moving each lens group in the optical axis direction. As the lens group in such a lens barrel, there are a lens group (hereinafter referred to as a rotating lens group) that is extended while rotating in the optical axis direction, and a lens group that is linearly extended without rotating ( Less than,
There is a straight lens group).

On the other hand, when a drive motor for driving the shutter mechanism and the diaphragm mechanism is arranged in the lens barrel, this drive unit is generally fixed to the moving frame of one of the lens groups.

When the drive motor is fixed to the linear lens group, the electric connection between the drive motor and the camera body is relatively easy. However, providing the drive motor for the rotary lens group is a wiring system. This has not been done so far because of problems such as twisting. However, due to the design of the lens barrel, it is often preferable to fix the drive motor to the rotary lens group.

In such a case, a design change must be made in order to avoid fixing the drive motor to the rotary lens group, and the degree of freedom in designing the lens barrel has been limited.

[0006]

SUMMARY OF THE INVENTION Therefore, a technical problem to be solved by the present invention is to electrically drive a drive motor fixed to a moving frame of a lens group which is extended while rotating in a lens barrel and a camera body. To provide a mechanical connection mechanism, thereby increasing the degree of freedom in designing the lens barrel.

[0007]

The present invention was devised to effectively solve the above problems, and provides an electrical connection mechanism having the following configuration.

That is, the electrical connection mechanism of the present invention electrically connects the drive motor fixed to the lens group rotation moving frame and the circuit board fixed to the lens barrel main body using a flexible flat cable. To connect. Then, the circuit board is further electrically connected to the camera body side. 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 together with the rotation lens group. Is.

The flexible flat cable includes an arch-shaped curved portion whose first end is fixed to the drive motor and whose second end is fixed to a support that is immovable with respect to the lens barrel body. The drive motor , support and
The flexible flat cable and the flexible flat cable are located on a virtual cylindrical surface having the optical axis of the photographing as an axis.

The first end of the curved portion of the flexible flat cable is fixed to the drive motor with its tangential direction 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 support portion in a state where the tangential direction thereof coincides with the tangential direction of the virtual cylindrical surface and is located in a plane orthogonal to the photographing optical axis. And the bay of flexible flat cable
In the curved part, the drive motor and the support part are the most in the shooting optical axis direction.
When separated, spirals along the virtual cylindrical surface
From the drive motor to the support. Also, with a drive motor
When the support is closest to the shooting optical axis
The curved part of the flexible flat cable is
A part overlaps in the optical axis direction along the virtual cylindrical surface. And
Flexible between states between these two states
The curved part of the flat cable runs along the above virtual cylindrical surface.
Move along the optical axis.

In the electrical connection mechanism having the above structure, a drive motor fixed to the lens group rotation moving frame (for example, a drive motor such as an aperture unit or a shutter unit arranged in the lens barrel) and a camera body. The flexible flat cable that communicates with the side is always housed in a limited cylindrical region along the virtual cylindrical surface when the lens group rotating / moving frame is rotationally extended. Therefore, if any cylindrical member that moves in the optical axis direction is placed along this virtual cylindrical surface within the lens barrel, the flexible flat cable will excessively contact the cylindrical member when the lens barrel expands and contracts. The flexible flat cable can be favorably accommodated in the lens barrel. That is, the drive motor can be fixed to the lens group rotation moving frame, and therefore, the degree of freedom in designing the lens barrel can be increased.

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

In the present specification, "each end of the flexible flat cable is located in one of the planes", "the tangential direction is parallel to the photographing optical axis", and "the end of the flexible flat cable is It goes without saying that, when the tangential direction and the tangential direction of the virtual cylindrical surface are coincident with each other, etc., they do not necessarily mean in a strict sense and if they are substantial.

[0014]

Embodiments of the present invention will be described in detail below 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 consists of four lens groups 10
The second lens group 20 is composed of 0, 200, 300, and 400.
It is a two-group focus type four-component zoom lens that performs focusing by 0. The third of this lens barrel
The lens group 300 is a rotating lens group that is extended while rotating around the optical axis during zooming.

The third lens group 300 is fixed to the third group moving frame (lens group rotation moving frame) 302 at its ball frame 301. That is, the moving frame 302 for the third lens group is also extended while rotating around the optical axis during zooming.
A guide pin 303 is fixed to the third group moving frame 302,
The guide pin 303 is connected to a predetermined drive mechanism.
Further, the diaphragm 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 leg portions 33 formed around the base plate 32 are provided. The guide pin 303 shown in FIG. 1 is fixed to the leg portion 33. Note that the illustration of the leg portion 33 is omitted in FIG.

On the lower surface of the base plate 32 in FIG.
Is provided. A drive motor 20 that operates the diaphragm mechanism 10 is arranged on the upper surface of the base plate 32. The output shaft of the drive motor 20 projects through the through hole formed in the base plate 32 to the lower surface side where the diaphragm mechanism 10 is provided, and the gear 21 fixed there operates the diaphragm mechanism 10.

The drive motor 20 is electrically connected to the camera body side using a flexible flat cable 60 (hereinafter referred to as a flat cable), and operates by receiving electric power from the camera body side. In FIG. 3, a part of the flat cable 60 is shown in a stretched 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 in the stretched state are wholly in one plane. The boundary between the curved portion 62 and the second straight portion 64 (that is, the end portion of the curved portion) is the corner portion 63. Further, the connecting portion 65 connected to the second linear portion 64 has a circuit board 40 (FIG. 1) fixed to the interchangeable lens body.
(See reference). The circuit board 40 is further electrically connected to the camera body side by a mechanism (not shown).

The behavior of the flat cable 60 when the movable 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 in which the entire lens barrel is extended, and FIGS. 4 (b-1) and (b-2) show a state in which the entire lens barrel is reduced. There is. 4 (a-1) and (b-1)
4 (a-2) and (b-2) are top views, respectively, and the upward direction in FIGS. 4 (a-2) and (b-2) is the rightward direction in FIG. Is consistent with. Further, FIG. 5 shows a side view of FIG. 4 (a-2) viewed from the arrow C direction.

As described above, the third group moving frame 302 is constructed so as to be rotationally extended. That is, in FIG.
From the states (-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 (a-2). It becomes the state of. On the contrary, FIG.
From the states (-1) and (a-2), the third-group moving frame 302 rotates in the direction of arrow A1 and is drawn in the direction of arrow B1 to obtain the state shown in FIGS. 4 (b-1) and (b-2). It becomes the state of. In addition, in FIG.
Reference numeral 401 denotes a straight-ahead guide key also shown in FIG. 1, which guides the movement of the fourth lens group 400. Straight ahead guidance key 4
01 is fixed to the fixed barrel 500 at a connecting portion 402 that is bent at a right angle. The fixed barrel 500 is fixed immovably to the interchangeable lens body, and therefore, the straight guide key 401
Is immovable 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). It should be noted that the first straight portion 61 can be omitted. In that case, the end portion of the curved portion is fixed to the side surface of the motor with the tangential direction of the curved portion parallel to the photographing optical axis.

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

As can be seen from FIGS. 4 (a-1) and 4 (b-1),
In the corner portion 63 of the curved portion 62, with the tangential direction thereof aligned with the tangential direction of the virtual cylindrical surface 50, the connecting portion 40
2 It is fixed on the upper surface. In the illustrated example,
The flat cable 60 has a corner 63 at the end of the curved portion 62.
In FIG. 1, the right-angled portion is connected to the second straight line portion 64 at a right angle, but such a right-angled portion is not always necessary. The end of the curved portion 62 has its tangential direction as a virtual cylindrical surface.
It suffices if it is fixed to the upper surface of the connecting portion 402 in a state where it is aligned with the tangential direction of 50, for example, the second straight line portion
May be connected to the end of the curved portion 62 in a state of being coincident with the tangential direction thereof. Further, in the illustrated example, the connecting portion 402 is used as the supporting portion, but the supporting portion may be immovable with respect to the interchangeable lens body, and other lens barrel constituent portions may be appropriately used.

As can be seen from FIG. 4, the tips of the connecting portions of the drive motor 20 and the linear guide key are arranged along the virtual cylindrical surface 50. That is, even when the third-group moving frame 302 is rotationally extended, the distances between the drive motor 20 and the tip of the connecting portion from the photographing optical axis are always kept substantially equal. The length of the curved portion 62 of the flat cable 60 is connected to the drive motor 20 on the peripheral surface of the virtual cylindrical surface 50 in a state where the drive motor 20 and the tip of the connecting portion 40 are farthest from each other in the shooting optical axis direction. It is set to be approximately equal to the distance connecting the tip of the part in a spiral shape.

Therefore, when the drive motor 20 and the tip of the connecting portion are most distant from each other in the photographing optical axis direction, the curved portion 62 extends in an arc shape along the virtual cylindrical surface 50 when observed from the optical axis direction ( See Fig. 4 (a-1). And drive motor 2
When 0 and the tip of the connecting part are closest to each other in the shooting 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 shape 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 movable frame that is rotationally extended, the flat cable 60 that connects the drive motor 20 and the camera body side is always virtual. It will be accommodated in a limited cylindrical region along the cylindrical surface 50. In practice, any tubular member that moves in the optical axis direction inside the lens barrel is arranged at the position of this virtual cylindrical surface (in the example shown, the moving frame 400a of the fourth lens group 400). ) But
It is possible to prevent the flat cable 60 from excessively contacting the tubular member when the lens barrel expands and contracts.

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

[Brief description of drawings]

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

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

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

4A and 4B are explanatory diagrams for explaining the behavior of the flexible flat cable in the zoom lens barrel of FIG.

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

[Explanation of symbols]

10 Aperture mechanism 20 drive motor 21 gears 31 Cylindrical member 32 base plate 33 legs 40 circuit board 50 virtual cylindrical surface 60 flexible flat cable 61 First straight line 62 curved part 63 Corner 64 Second straight part 65 connection 100, 200, 300, 400 lens group 301 ball frame 302 Third lens group moving frame (lens group rotation moving frame) 303 guide pin 401 straight ahead guidance key 402 connection 500 fixed tube

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Claims (2)

(57) [Claims] 1. A drive motor fixed to a lens group rotating / moving frame which is arranged in the lens barrel and is rotated around an image pickup optical axis, and a circuit board fixed to the lens barrel body. And a flexible flat cable for electrically connecting the first end to the drive motor and the second end immovable with respect to the lens barrel main body. Includes an arched curved section that is fixed to the support , the drive motor , the support and the flexible flat cable
Le, respectively, are located on a virtual cylindrical surface whose axial center of the photographing optical axis, a first end of the curved portion, and parallel to its tangential direction to the photographing optical axis, and includes a photographing optical axis In the state of being located in the plane,
The second end of the curved portion is fixed to the drive motor, the tangential direction of which coincides with the tangential direction of the virtual cylindrical surface, and the second end of the curved portion is positioned in a plane orthogonal to the photographing optical axis. The curved part of the flexible flat cable is fixed to the drive mode.
The monitor and the support are the farthest from each other in the shooting optical axis direction.
Supported by the drive motor spirally along the virtual cylindrical surface.
While reaching the holding part, in the state closest to the above,
A part of them overlap in the optical axis direction along the virtual cylindrical surface,
In the states between the states, the curved portion is the virtual cylinder.
An electrical connection mechanism that moves along the surface in the optical axis direction . 2. The curved portion of the flexible flat cable is fixed to a drive motor at a straight line portion provided at a first end of the flexible flat cable, and the straight line portion extends in parallel with a photographing optical axis. The electrical connection mechanism according to claim 1, wherein: