GB2309531A

GB2309531A - Flexible printed circuit board housing structure for a camera

Info

Publication number: GB2309531A
Application number: GB9701483A
Authority: GB
Inventors: Hiroshi Nomura; Kazuyoshi Azegami; Takamitsu Sasaki
Original assignee: Asahi Kogaku Kogyo Co Ltd
Current assignee: Pentax Corp
Priority date: 1996-01-26
Filing date: 1997-01-24
Publication date: 1997-07-30
Anticipated expiration: 2017-01-24
Also published as: GB2309531B; GB9701483D0

Abstract

A camera body has a fixed lens barrel block (12) slidably locating a barrel (16) to move along the optical axis. A curved wall (80a) of a film chamber (80) and a wall (12q) of the barrel block together with a fixing part (12m) define a space (81). A relief hole (12k) is formed in the barrel block to open into this space and a spring (82) is located in the space. The spring is attached to a portion (6f, 6g) of a flexible printed circuit board (6) which passes through the relief hole so that slack in the portion of the flexible printed circuit board is urged to be housed in the space.

Description

Flexible Printed Circuit Board Housing Structure for a Camera The present invention relates to a flexible printed circuit board housing structure for a camera.

A camera that is provided with a movable barrel includes a flexible printed circuit board (FPC) to electrically connect electrical units, such as a shutter or the like, on the movable barrel to a control unit on the camera such that control signals can be transmitted and received.

As the movable barrel moves, the flexible printed circuit board will sometimes be slack. In this case, the flexible printed circuit board may interfere with the movement of the movable barrel or with light passing through the camera aperture.

In order to avoid the problems caused by slack in the flexible printed circuit board, a housing structure can be provided on the movable barrel or on the camera body in which the slack in the flexible printed circuit board is taken up or paid out. However, methods of taking up and paying out the slack in the flexible printed circuit board are typically complicated and require a large number of additional components. Furthermore, the provision of such a housing structure makes the size of the movable barrel or the camera larger.

It is therefore an object of the present invention to provide an improved flexible printed circuit board housing structure that is small and has a simple arrangement.

According to one aspect of the present invention, there is provided a flexible printed circuit board housing structure for a camera. In particular, the camera includes a movable barrel and a flexible printed circuit board. The movable barrel is movable along the optical axis of the camera and the flexible printed circuit board is connected between an electrical unit on the movable barrel and a control unit on the camera.

The flexible printed circuit board housing structure includes an FPC housing space and a spring mechanism.

The FPC housing space is formed on the camera for storage of the flexible printed circuit board.

The spring mechanism is provided in the FPC housing space such that the spring mechanism applies an urging force to urge the flexible printed circuit board into the FPC housing space.

Preferably, the spring mechanism urges the flexible printed circuit board in a direction perpendicular to the optical axis of said camera.

In a particular case, an end of the flexible printed circuit board may be fixed to the FPC housing space, and a slot, which is a predetermined length, may be formed lengthwise on a part of the flexible printed circuit board that is located inside the FPC housing space near to the fixed end of the flexible printed circuit board. Further, the spring mechanism may include a spring bearing pin that is movably fitted into the slot and the urging force of the spring mechanism is applied to the flexible printed circuit board via the spring bearing pin.

With the arrangement above, the flexible printed circuit board is urged into the FPC housing space using a simple spring mechanism and further, since the spring urges the flexible printed circuit board perpendicular to the optical axis and the action of the spring mechanism acts on a lengthwise slot on the flexible printed circuit board, the range of movement of the spring mechanism is small in relation to the amount of flexible printed circuit board urged into the FPC housing space such that less space is required for the spring mechanism.

Also preferably, the FPC housing space is formed to include a curved surface which is positioned such that, as the spring mechanism urges the flexible printed circuit board into the FPC housing space, the flexible printed circuit board curves around the curved surface. Using a curved surface to curve the flexible printed circuit board allows a greater length of the printed circuit board to be urged into the FPC housing space than if the flexible printed circuit board were straight.

According to another aspect of the present invention, the flexible printed circuit board housing structure may be applied to a camera that includes a control unit, a film chamber, a camera aperture, a stationary barrel, a movable barrel, and a flexible printed circuit board.

The stationary barrel is positioned in front of the camera aperture and the movable barrel is supported on the stationary barrel in a manner enabling movement in the optical axis direction. The movable barrel houses an electrical unit and the flexible printed circuit board is connected between the electrical unit and the control unit.

In this case, the flexible printed circuit board housing structure includes an FPC housing space and an FPC relief hole.

The FPC housing space may be formed between the stationary barrel and a substantially cylindrical outer face of the film chamber and the FPC relief hole may be formed in the stationary barrel to pass through the stationary barrel to the FPC housing space.

In particular, the flexible printed circuit board may be lead via the FPC relief hole to the FPC housing space.

In this aspect of the invention, the term "film chamber" may be, for example, a cartridge chamber for storing unexposed film or as a wind-up chamber for storing exposed film.

In this way, the FPC housing space may be formed in otherwise unused space ("dead space"), that is, the space between the substantially cylindrical outer face of the film chamber and the stationary barrel, so that the size of the camera is not increased in providing the FPC housing space.

Preferably, the FPC relief hole is formed at a position which is a middle point of the range of movement of the movable barrel. This arrangement ensures that slack in the flexible printed circuit board is adequately taken up without undue stress on the flexible printed circuit board.

Further preferably, the FPC housing space is provided with a spring mechanism that applies an urging force to urge the flexible printed circuit board into the FPC housing space.

As above, preferably, the spring mechanism urges the flexible printed circuit board in a direction perpendicular to the optical axis of said camera.

Also, as above, in a particular case, an end of the flexible printed circuit board is fixed to the FPC housing space, and a slot, which is a predetermined length, is formed lengthwise on a part of the flexible printed circuit board that is located inside the FPC housing space near to the fixed end of the flexible printed circuit board.

Further, the spring mechanism includes a spring bearing pin that is movably fitted into the slot and the urging force of the spring mechanism is applied to the flexible printed circuit board via the spring bearing pin.

An example of the present invention will now be described with reference to the accompanying drawings, in which: Fig. 1 is an enlarged schematic perspective view showing a part of a zoom lens barrel; Fig. 2 is a schematic perspective view showing the part of the zoom lens barrel of Fig. 1 in an engaged state; Fig. 3 is an enlarged exploded perspective view showing another part of the zoom lens barrel; Fig. 4 is a schematic perspective view illustrating a state where an AF/AE shutter unit of the zoom lens barrel is mounted to a first movable barrel; Fig. 5 is an exploded perspective view illustrating main parts of the AF/AE shutter unit of the zoom lens barrel; Fig. 6 is an external schematic perspective view of a third movable barrel of the zoom lens barrel; Fig. 7 is a front elevational view of a fixed lens barrel block of the zoom lens barrel; Fig. 8 is a sectional view of an upper part of the zoom lens barrel in a maximum extended state; Fig. 9 is a sectional view of an upper part of the zoom lens barrel in a housed state; Fig. 10 is an exploded perspective view of the overall structure of the zoom lens barrel; Fig. 11 is a block diagram of a controlling system for controlling an operation of the zoom lens barrel; Fig. 12 is an external perspective view which shows major parts of the zoom lens barrel; Fig. 13 is a sectional plan view of a flexible printed circuit board (FPC) housing structure embodying the present invention with a retracted zoom lens barrel; Fig. 14 is a sectional plan view of the FPC housing structure of Fig. 13 with an extended zoom lens barrel; Fig. 15 is an enlarged front view showing the structure of an end part of a flexible printed circuit board; Fig. 16 is an enlarged side view showing the structure of the end part of the flexible printed circuit board; Fig. 17 is a perspective view of an assembly of three barrels; Fig. 18 is an external perspective view of a fixed lens barrel block; Fig. 19 is an exploded perspective view showing the zoom lens barrel; Fig. 20 is an enlarged perspective view showing a rectilinear guide barrel of the zoom lens barrel; and Fig. 21 is a cross-section showing a spring support at an end of a rectilinear guide member of the zoom lens barrel.

An embodiment of a flexible printed circuit board housing structure is applied to a lens-shutter type zoom lens camera.

Referring to the drawings, figure 11 is a schematic representation of various elements which comprise a zoom lens camera of the present invention. The concept of the zoom lens camera will now be described with reference to Figure 11.

The zoom lens camera is provided with a zoom lens barrel 10 of a three-stage delivery type having three movable barrels, namely a first movable barrel 20, a second movable barrel 19 and a third movable barrel 16, which are concentrically arranged in this order from an optical axis O. In the zoom lens barrel 10, two lens groups are provided, namely a front lens group L1 having positive power and a rear lens group L2 having negative power.

In a camera body, a whole optical unit driving motor controller 60, a rear lens group driving motor controller 61, a zoom operating device 62, a focus operating device 63, an object distance measuring apparatus 64, a photometering apparatus 65, and an AE (i.e., automatic exposure) motor controller 66, are provided. Although the specific focusing system of the object distance measuring apparatus 64, which is used to provide information regarding the object-tocamera distance, does not form part of the present invention, one such suitable system is disclosed in commonly assigned U.S. Patent Application S.N. 08/605,759, filed on February 22, 1996, the entire disclosure of which is expressly incorporated by reference herein. Although the focusing systems disclosed in U.S. Patent Application S.N.

08/605,759 are of the so-called "passive" type, other known autofocus systems (e.g., active range finding systems such as those based on infrared light and triangulation) may be used. Similarly, a photometering system as disclosed in the above-noted U.S. Patent Application S.N. 08/605,759 could be implemented as photometering apparatus 65.

The zoom operating device 62 can be provided in the form of, for example, a manually-operable zoom operating lever (not shown) provided on the camera body or a pair of zoom buttons, e.g., a "wide" zoom button and a "tele" zoom button, (not shown) provided on the camera body. When the zoom operating device 62 is operated, the whole optical unit driving motor controller 60 drives a whole optical unit driving motor 25 to move the front lens group L1 and the rear lens group L2, rearwardly or forwardly. In the following explanation, forward and rearward movements of the lens groups L1 and L2 by the whole optical unit driving motor controller 60 (the motor 25) are referred to as the movement toward "tele" and the movement toward "wide" respectively, since forward and rearward movements of the lens groups L1 and L2 occur when the zoom operating device 62 is operated to "tele" and "wide" positions.

The image magnification of the visual field of a zoom finder 67 provided in the camera body varies sequentially with the variation of the focal length through the operation of the zoom operating device 62. Therefore, the photographer will see the variation of the set focal length through the operation of the zoom operating device 62 by observing the variation of the image magnification of the visual field of the finder. In addition, the focal length, set by the operation of the zoom operating device 62, may be seen by a value indicated on an LCD (liquid crystal display) panel (not shown) or the like.

When the focus operating device 63 is operated, the whole optical unit driving motor controller 60 drives the whole optical unit driving motor 25. At the same time the rear lens group driving motor controller 61 drives a rear lens group driving motor 30. Due to the driving of the whole optical unit driving motor controller 60 and the rear lens group driving motor controller 61, the front and rear lens groups L1 and L2 are moved to respective positions corresponding to a set focal length and a detected object distance and thereby the zoom lens is focused on the object.

Specifically, the focus operating device 63 is provided with a release button (not shown) provided on an upper wall of the camera body. A photometering switch and a release switch (both not shown) are synchronized with the release button. When the release button is half-depressed (half step), the photometering switch is turned ON, and the object distance measuring and photometering commands are respectively input to the object distance measuring apparatus 64 and the photometering apparatus 65.

When the release button is fully depressed (full step), the release switch is turned ON, and according to the result of an object distance measuring command and a set focal length, the whole optical unit driving motor 25 and the rear lens group driving motor 30 are driven, and the focusing operation, in which the front lens group L1 and the rear lens group L2 move to the focusing position, is executed.

Further, an AE motor 29 of an AF/AE (i.e., autofocus/autoexposure) shutter unit 21 (Figure 9) is driven via the AE motor controller 66 to actuate a shutter 27.

During the shutter action, the AE motor controller 66 drives the AE motor 29 to open shutter blades 27a of the shutter 27 for a specified period of time according to the photometering information output from the photometering apparatus 65.

When the zoom operating device 62 is operated, the zoom operating device 62 drives the whole optical unit driving motor 25 to move the front and rear lens groups L1 and L2 together as a whole in the direction of the optical axis 0 (optical axis direction). Simultaneous with such a movement, the rear lens group driving motor 30 may also be driven via the rear lens group driving motor controller 61 to move the rear lens group L2 relative to the front lens group L1.

However, this is not performed under the conventional concept of zooming, in which the focal length is varied sequentially while keeping an in-focus condition. When the zoom operating device 62 is operated, the front lens group L1 and the rear lens group L2 is moved in the optical axis direction without varying the distance therebetween, by driving only the whole optical unit driving motor 25.

During the zooming operation, an in-focus condition cannot be obtained at all times with respect to an object located at a specific distance. However, this is not a problem in a lens-shutter type camera, since the image of the object is not observed through the photographing optical system, but through the finder optical system that is provided separate from the photographing optical system, and it is sufficient that the in-focus condition is obtained when the shutter is released. Thus, when the release button is fully depressed, the focusing operation (focus adjusting operation) is carried out by moving at least one of the whole optical unit driving motor 25 and the rear lens group driving motor 30. In such a manner, since each of the two lens groups L1, L2 can be driven independently, when the focus operating device 63 is operated, the position of the lens groups L1, L2 can be flexibly controlled.

An embodiment of the zoom lens barrel using the above concept will now be described mainly with reference to Figures 9 and 10.

The overall structure of the zoom lens barrel 10 will firstly be described.

The zoom lens barrel 10 is provided with the first movable barrel 20, the second movable barrel 19, the third movable barrel 16, and a fixed lens barrel block 12. The third movable barrel 16 is engaged with a cylindrical portion 12p of the fixed lens barrel block 12, and moves along the optical axis 0 upon being rotated. The third movable barrel 16 is provided on an inner periphery thereof with a linear guide barrel 17, which is restricted in rotation. The linear guide barrel 17 and the third movable barrel 16 move together as a whole along the optical axis 0, with the third movable barrel 16 rotating relative to the linear guide barrel 17. The first movable barrel 20 moves along the optical axis 0 with rotation thereof being restricted. The second movable barrel 19 moves along the optical axis 0, while rotating relative to the linear guide barrel 17 and the first movable barrel 20. The whole optical unit driving motor 25 is secured to the fixed lens barrel block 12. A shutter mounting stage 40 is secured to the first movable barrel 20. The AE motor 29 and the rear lens group driving motor 30 are mounted on the shutter mounting stage 40. The front lens group L1 and the rear lens group L2 are respectively supported by a lens supporting barrel (lens supporting annular member) 34 and a lens supporting barrel 50.

The fixed lens barrel block 12 is fixed in front of an aperture plate 14 fixed to the camera body. The aperture plate 14 is provided at a centre thereof with a rectangular shaped aperture 14a which forms the limits of each frame exposed. The fixed lens barrel block 12 is provided on an inner periphery of the cylindrical portion 12p thereof with a female helicoid 12a, and also a plurality of linear guide grooves 12b each extending parallel to the optical axis 0, i.e. extending in the optical axis direction. At the bottom of one of the linear guide grooves 12b, namely 12b', a code plate 13a having a predetermined code pattern is fixed. The code plate 13a extends in the optical axis direction and extends along substantially the whole of the length of the fixed lens barrel block 12. The code plate 13a is part of a flexible printed circuit board 13 positioned outside the fixed lens barrel block 12.

In the fixed lens barrel block 12, a gear housing 12c, which is recessed outwardly from an inner periphery of the cylindrical portion 12p of the fixed lens barrel block 12 in a radial direction while extending in the optical axis direction, is provided as shown in Figure 7 or 10. In the gear housing 12c, a driving pinion 15 extending in the optical axis direction is rotatably positioned. Opposing ends of an axial shaft 7 of the driving pinion 15 are respectively rotatably supported by a supporting hollow 4 provided in the fixed lens barrel block 12, and a supporting hollow 3la provided on a gear supporting plate 31 fixed on the fixed lens barrel block 12 by set screws (not shown).

Part of the teeth of the driving pinion 15 project inwardly from the inner periphery of the cylindrical portion of the fixed lens barrel block 12 so that the driving pinion 15 meshes with an outer peripheral gear 16b of the third movable barrel 16 as shown in Figure 7.

On an inner periphery of the third movable barrel 16, a plurality of linear guide grooves 16c, each extending parallel to the optical axis 0, are formed. At an outer periphery of the rear end of the third movable barrel 16, a male helicoid 16a and the aforementioned outer peripheral gear 16b are provided as shown in Figure 6. The male helicoid 16a engages with the female helicoid 12a of the fixed lens barrel block 12. The outer peripheral gear 16b engages with the driving pinion 15. The driving pinion 15 has an axial length sufficient to be capable of engaging with the outer peripheral gear 16b throughout the entire range of movement of the third movable barrel 16 in the optical axis direction.

As shown in Figure 10, the linear guide barrel 17 is provided on a rear part of an outer periphery thereof with a rear end flange 17d. The rear end flange 17d has a plurality of engaging projections 17e each projecting away from the optical axis 0 in a radial direction. The linear guide barrel 17 is further provided, in front of the rear end flange 17d, with an anti-dropping flange 17e. A circumferential groove 17g is formed between the rear end flange 17d and the anti-dropping flange 17e. The antidropping flange 17e has a radius smaller than the rear end flange 17d. The anti-dropping flange 17e is provided with a plurality of cutout portions 17f. Each of the cutout portions 17f allows a corresponding engaging projection 16d to be inserted into the circumferential groove 17g, as shown in Figure 9.

The third movable barrel 16 is provided on an inner periphery of the rear end thereof with the plurality of engaging projections 16d. Each of the engaging projections 16d projects towards the optical axis 0 in a radial direction. By inserting the engaging projections 16d into the circumferential groove 17g, through the corresponding cutout portions 17f, the engaging projections 16d are positioned in the circumferential groove 17g between the flanges 17d and 17e (See Figure 9). By rotating the third movable barrel 16 relative to the linear guide barrel 17, the engaging projections 16d are engaged with the linear guide barrel 17.

On the rear end of the linear guide barrel 17, an aperture plate 23 having a rectangular-shaped aperture 23a approximately the same shape as the aperture 14a, is fixed.

The relative rotation of the linear guide barrel 17 with respect to the fixed lens barrel block 12 is restricted by the slidable engagement of the plurality of engaging projections 17e with the corresponding linear guide grooves 12b, formed parallel to the optical axis 0.

A contacting terminal 9 is fixed to one of the engaging projections 17c, namely 17c'. The contacting terminal 9 is in slidable contact with the code plate 13a fixed to the bottom of the linear guide groove 12b' to generate signals corresponding to focal length information during zooming.

On the inner periphery of the linear guide barrel 17 a plurality of linear guide grooves 17a are formed, each extending parallel to the optical axis 0. A plurality of lead slots 17b are also formed on the linear guide barrel 17 as shown in Figure 10. The lead slots 17b are each formed oblique (inclined) to the optical axis 0.

The second movable barrel 19 engages with the inner periphery of the linear guide barrel 17. On the inner periphery of the second movable barrel 19, a plurality of lead grooves 19c are provided in a direction inclined oppositely to the lead slots 17b. On the outer periphery of the rear end of the second movable barrel 19 a plurality of follower projections 19a are provided. Each of the follower projections 19a has a trapezoidal cross-sectional shape projecting away from the optical axis 0 in a radial direction. Follower pins 18 are positioned in the follower projections 19a. Each follower pin 18 consists of a ring member 18a, and a centre fixing screw 18b which supports the ring member 18a on the corresponding follower projection 19a. The follower projections 19a are in slidable engagement with the lead slots 17b of the linear guide barrel 17, and the follower pins 18 are in slidable engagement with the linear guide grooves 16c of the third movable barrel 16.

With such an arrangement, when the third movable barrel 16 rotates, the second movable barrel 19 moves linearly in the optical axis direction, while rotating.

On the inner periphery of the second movable barrel 19, the first movable barrel 20 is engaged. The first movable barrel 20 is provided on an outer periphery of the rear end thereof with a plurality of follower pins 24 each engaging with the corresponding inner lead groove 19c, and at the same time the first movable barrel 20 is guided linearly by a linear guide member 22. The first movable barrel 20 is provided at the front end thereof with a decorative plate 41.

As shown in Figures 1 and 2, the linear guide member 22 is provided with an annular member 22a, a pair of guide legs 22b and a plurality of engaging projections 28. The pair of guide legs 22b project from the annular member 22a in the optical axis direction. The plurality of engaging projections 28 each project from the annular member 22a away from the optical axis 0 in a radial direction. The engaging projections 28 slidably engage with the linear guide grooves 17a. The guide legs 22b are respectively inserted into linear guides 40c defined between the inner peripheral surface of the first movable barrel 20 and the AF/AE shutter unit 21.

The annular member 22a of the linear guide member 22 is connected to the rear of the second movable barrel 19, such that the linear guide member 22 and the second movable barrel 19 are capable of moving along the optical axis 0 as a whole, and in addition are capable of relatively rotating around the optical axis 0. The linear guide member 22 is further provided on the outer periphery of the rear end thereof with a rear end flange 22d. The linear guide member 22 is further provided in front of the rear end flange 22d with an anti-dropping flange 22c. A circumferential groove 22f is formed between the rear end flange 22d and the antidropping flange 22c. The anti-dropping flange 22c has a radius smaller than the rear end flange 22d. The antidropping flange 22c is provided with a plurality of cutout portions 22e, as shown in Figure 1 or 2, each allowing a corresponding engaging projection l9b to be inserted into the circumferential groove 22f, as shown in Figure 9.

The second movable barrel 19 is provided on an inner periphery of the rear end thereof with a plurality of engaging projections l9b, each projecting towards the optical axis 0 in a radial direction. By inserting the engaging projections 19b into the circumferential groove 22f through the corresponding cutout portions 22e, the engaging projections 19b are positioned in the circumferential groove 22f between the flanges 22c and 22d. By rotating the second movable barrel 19 relative to the linear guide member 22, the engaging projections l9b are engaged with the linear guide member 22. With the above structure, when the second movable barrel 19 rotates in the forward or reverse rotational direction, the first movable barrel 20 moves linearly forwardly or rearwardly along the optical axis 0, but is restricted from rotating.

At the front of the first movable barrel 20, a barrier apparatus 35 having barrier blades 48a and 48b is mounted.

On an inner peripheral face of the first movable barrel 20 the AF/AE shutter unit 21 having the shutter 27, consisting of three shutter blades 27a, is engaged and fixed, as shown in Figure 8. The AF/AE shutter unit 21 is provided with a plurality of fixing holes 40a formed at even angular intervals on the outer periphery of the shutter mounting stage 40. Only one of the fixing holes 40a appears in each of Figures 1 through 5.

The aforementioned plurality of follower pins 24, which engage with the inner lead grooves l9c, also serve as a device for fixing the AF/AE shutter unit 21 to the first movable barrel 20. The follower pins 24 are inserted and fixed in holes 20a formed on the first movable barrel 20, and in the fixing holes 40a. With this arrangement the AF/AE shutter unit 21 is secured to the first movable barrel 20 as shown in Figure 4. In Figure 4 the first movable barrel 20 is indicated by phantom lines. The follower pins 24 may be fixed by an adhesive, or the pins 24 may be formed as screws to be screwed into the fixing holes 40a.

As illustrated in Figures 5 and 10, the AF/AE shutter unit 21 is provided with the shutter mounting stage 40, a shutter blade supporting ring 46 fixed on the rear of the shutter mounting stage 40 so as to be located inside the shutter mounting stage 40, and the lens supporting barrel 50 supported in a state of being capable of movement relative to the shutter mounting stage 40. On the shutter mounting stage 40, the lens supporting barrel 34, the AE motor 29, and the rear lens group driving motor 30, are supported. The shutter mounting stage 40 is provided with an annular member 40f having a circular aperture 40d. The shutter mounting stage 40 is also provided with three legs 40b which project rearward from the annular member 40f. Three slits are defined between the three legs 40b. Two of the slits comprise the aforementioned linear guides 40c which slidably engage with the respective pair of guide legs 22b of the linear guide member 22 so as to guide the movement of the linear guide member 22.

The shutter mounting stage 40 supports an AE gear train 45 which transmits a rotation of the AE motor 29 to the shutter 27, a lens driving gear train 42 which transmits rotation of the rear lens group driving motor 30 to a screw shaft 43, photointerrupters 56 and 57 connected to a flexible printed circuit board 6, and rotating disks 58 and 59 having a plurality of radially fo rotating disk 59. An AE motor encoder for detecting whether the AE motor 29 is rotating and for detecting an amount of rotation of the AE motor 29 comprises the photointerrupter 56 and the rotating disk 58.

The shutter 27, a supporting member 47 which pivotally supports the three shutter blades 27a of the shutter 27, and a circular driving member 49, which gives rotative power to the shutter blades 27a, are positioned between the shutter mounting stage 40 and the shutter blade supporting ring 46 secured to the shutter mounting stage 40. The circular driving member 49 is provided with three operating projections 49a at even angular intervals which respectively engage with each of the three shutter blades 27a. As shown in Figure 5, the shutter blade supporting ring 46 is provided at a front end thereof with a circular aperture 46a and with three supporting holes 46b positioned at even angular intervals around the circular aperture 46a. Two deflection restricting surfaces 46c are formed on the outer periphery of the shutter blade supporting ring 46. Each deflection restricting surface 46c is exposed outwardly from the corresponding linear guide 40c and slidably supports the inner peripheral face of the corresponding guide leg 22b.

The supporting member 47, positioned in front of the shutter blade supporting ring 46, is provided with a circular aperture 47a aligned with the circular aperture 46a of the shutter blade supporting ring 46, and with three pivotal shafts 47b (only one of which is illustrated in Figure 10) at respective positions opposite the three supporting holes 46b. Each shutter blade 27a is provided at one end thereof with a hole 27b into which the corresponding pivotal shaft 47b is inserted so that each shutter blade 27a is rotatable about the corresponding pivotal shaft 47b. The major part of each shutter blade 27a that extends normal to the optical axis 0 from the pivoted end is formed as a light-interceptive portion. All three light-interceptive portions of the shutter blades 27a together prevent ambient light, which enters the front lens group L1, from entering the circular apertures 46a and 47a when the shutter blades 27a are closed. Each shutter blade 27a is further provided, between the hole 27b and the light-interceptive portion thereof, with a slot 27c through which the corresponding operating projection 49a is inserted. The supporting member 47 is fixed to the shutter blade supporting ring 46 in such a manner that each shaft 47b, which supports the corresponding shutter blade 27a, is engaged with the corresponding supporting hole 46b of the shutter blade supporting ring 46.

A gear portion 49b is formed on a part of the outer periphery of the circular driving member 49. The gear portion 49b meshes with one of the plurality of gears in the gear train 45 to receive the rotation from the gear train 45. The supporting member 47 is provided at respective positions close to the three pivotal shafts 47b with three arc grooves 47c each arched along a circumferential direction. The three operating projections 49a of the circular driving ring 49 engage with the slots 27c of the respective shutter blades 27a through the respective arc grooves 47c. The shutter blade supporting ring 46 is inserted from the rear of the shutter mounting stage 40 to support the circular driving ring 49, the supporting member 47 and the shutter 27, and is fixed on the shutter mounting stage 40 by set screws 90 respectively inserted through holes 46d provided on the shutter blade supporting ring 46.

Behind the shutter blade supporting ring 46, the lens supporting barrel 50, supported to be able to move relative to the shutter mounting stage 40 via guide shafts 51 and 52, is positioned. The shutter mounting stage 40 and the lens supporting barrel 50 are biased in opposite directions away from each other by a coil spring 3 fitted on the guide shaft 51, and therefore play between the shutter mounting stage 40 and the lens supporting barrel 50 is reduced. In addition, a driving gear 42a, provided as one of the gears in the gear train 42, is provided with a female thread hole (not shown) at the axial centre thereof and is restricted to move in the axial direction. The screw shaft 43, one end of which is fixed to the lens supporting barrel 50, engages with the female thread hole of the driving gear 42a. Accordingly, the driving gear 42a and the screw shaft 43 together constitute a feed screw mechanism. In such a manner, when the driving gear 42a rotates forwardly or reversely due to driving by the rear lens group driving motor 30, the screw shaft 43 respectively moves forwardly or rearwardly with respect to the driving gear 42a, and therefore the lens supporting barrel 50 which supports the rear lens group L2 moves relative to the front lens group L1.

A holding member 53 is fixed at the front of the shutter mounting stage 40. The holding member 53 holds the motors 29 and 30 between the holding member 53 and the shutter mounting stage 40. The holding member 53 has a metal holding plate 55 fixed at the front thereof by set screws (not shown). The motors 29, 30 and the photointerrupters 56, 57 are connected to the flexible printed circuit board 6.

One end of the flexible printed circuit board 6 is fixed to the shutter mounting stage 40.

After the first, second and third movable barrels 20, 19 and 16, and the AF/AE shutter unit 21 and the like are assembled, the aperture plate 23 is fixed to the rear of the linear guide barrel 17, and a supporting member 33 having a circular shape is fixed at the front of the fixed lens barrel block 12.

In the above-described embodiment of the zoom lens barrel 10, although the zoom lens optical system comprises two movable lens groups, namely the front lens group L1 and the rear lens group L2, it should be understood that the present invention is not limited to the embodiment disclosed above, but the present invention may also be applied to another type of zoom lens optical system including one or more fixed lens groups.

In addition, in the above embodiment, the rear lens group L2 is supported on the AF/AE shutter unit 21, and the AE motor 29 and the rear lens group driving motor 30 are mounted to the AF/AE shutter unit 21. In this way, the structure for supporting the front and rear lens groups L1 and L2 and the structure for driving the rear lens group L2 are both simplified. Instead of adopting such a structure, the zoom lens barrel 10 may also be realized in such a manner that the rear lens group L2 is not supported by the AF/AE shutter unit 21, which is provided with the shutter mounting stage 40, the circular driving member 49, the supporting member 47, the shutter blades 27, the shutter blade supporting ring 46 and the like, and that the rear lens group L2 is supported by any supporting member other than the AF/AE shutter unit 21.

The operation of the zoom lens barrel 10, by rotation of the whole optical unit driving motor 25 and the rear lens group driving motor 30, will now be described with reference to Figures 8 and 9.

As shown in Figure 9, when the zoom lens barrel 10 is at the most retracted (withdrawn) position, i.e., the lenshoused condition, when the power switch is turned ON, the whole optical unit driving motor 25 is driven to rotate its drive shaft in the forward rotational direction by a small amount. This rotation of the motor 25 is transmitted to the driving pinion 15 through a gear train 26, which is supported by a supporting member 32 formed integral with the fixed lens barrel block 12, to thereby rotate the third movable barrel 16 in one predetermined rotational direction to advance forwardly along the optical axis 0. Therefore, the second movable barrel 19 and the first movable barrel 20 are each advanced by a small amount in the optical axis direction, along with the third movable barrel 16. In this way, the camera is in a state capable of photographing, with the zoom lens positioned at the widest position, i.e., the wide end. At this stage, due to the fact that the amount of movement of the linear guide barrel 17, with respect to the fixed lens barrel block 12, is detected through the relative sliding between the code plate 13a and the contacting terminal 9, the focal length can be detected.

In the photographable state as above described, when the aforementioned zoom operating lever is manually moved towards a "tele" side, or the "tele" zoom button is manually depressed to be turned ON, the whole optical unit driving motor 25 is driven to rotate its drive shaft in the forward rotational direction through the whole optical unit driving motor controller 60 so that the third movable barrel 16 rotates in the rotational direction to advance along the optical axis 0 via the driving pinion 15 and the outer peripheral gear 16b. Therefore, the third movable barrel 16 is advanced from the fixed lens barrel block 12 according to the relationship between the female helicoid 12a and the male helicoid 16a. At the same time, the linear guide barrel 17 moves forwardly along the optical axis 0 together with the third movable barrel 16 without relative rotation to the fixed lens barrel block 12 according to the relationship between the engaging projections 17c and the linear guide grooves 12b. At this time, the simultaneous engagement of the follower pins 18 with the respective lead slots 17b and linear guide grooves 16c causes the second movable barrel 19 to move forwardly relative to the third movable barrel 16 in the optical axis direction, while rotating together with the third movable barrel 16 in the same rotational direction relative to the fixed lens barrel block 12. The first movable barrel 20 moves forwardly along the optical axis 0 together with the AF/AE shutter unit 21, from the second movable barrel 19, without relative rotation to the fixed lens barrel block 12, due to the above-noted structures in which the first movable barrel 20 is guided linearly by the linear guide member 22 and in which the follower pins 24 are guided by the lead grooves 19c. During such movements, according to the fact that the moving position of the linear guide barrel 17 with respect to the fixed lens barrel block 12 is detected through the relative sliding between the code plate 13a and the contacting terminal 9, the focal length can be detected.

Conversely, when the zoom operating lever is manually moved towards a "wide side, or the "wide" zoom button is manually depressed to be turned ON, the whole optical unit driving motor 25 is driven to rotate its drive shaft in the reverse rotational direction through the whole optical unit driving motor controller 60 so that the third movable barrel 16 rotates in the rotational direction to retract into the fixed lens barrel block 12 together with the linear guide barrel 17. At the same time, the second movable barrel 19 is retracted into the third movable barrel 16, while rotating in the same direction as that of the third movable barrel 16, and the first movable barrel 20 is retracted into the rotating second movable barrel 19 together with the AF/AE shutter unit 21. During the above retraction driving, like the case of the advancing driving as above described, the rear lens group driving motor 30 is not driven.

While the zoom lens barrel 10 is driven during the zooming operation, since the rear lens group driving motor 30 is not driven, the front lens group L1 and the rear lens group L2 move as a whole, maintaining a constant distance between each other, as shown in Figure 8. The focal length input via the zoom code plate 13a and the contacting terminal 9 is indicated on an LCD panel (not shown) provided on the camera body.

At any focal length, when the release button is depressed by a half-step, the object distance measuring apparatus 64 is actuated to measure an object distance. At the same time the photometering apparatus 65 is actuated to measure an object brightness. Thereafter, when the release button is fully depressed, the whole optical unit driving motor 25 and the rear lens group driving motor 30 are each driven by respective amounts each corresponding to the focal length information set in advance and the object distance information obtained from the object distance measuring apparatus 64 so that the front and rear lens groups L1 and L2 are respectively moved to specified positions to obtain a specified focal length and also bring the object into focus. Immediately after the object is brought into focus, via the AE motor controller 66, the AE motor 29 is driven to rotate the circular driving member 49 by an amount corresponding to the object brightness information obtained from the photometering apparatus 65 so that the shutter 27 is driven to open the shutter blades 27a by a predetermined amount which satisfies the required exposure. Immediately after the three shutter blades 27a are opened and subsequently closed, the whole optical unit driving motor 25 and the rear lens group driving motor 30 are both driven to move the front lens group L1 and the rear lens group L2 to the respective initial positions which they were at prior to a shutter release.

An embodiment of the flexible printed circuit board housing structure is now described with reference to Figs.

8, 9 and 12-21.

As shown in Figs. 12 and 18, the fixed lens barrel block 12 is provided with a barrel portion 12p, an FPC fixing part 12m, and a supporting part 32. The supporting part 32 is formed on one side of the barrel portion 12p and the FPC fixing part 12m is formed on the other side, opposite the supporting part 32.

The FPC fixing part 12m is formed projecting sideways (i.e. toward the right as shown in Figs. 12 and 18) near the front of the barrel portion 12p. A flexible printed circuit board relief hole 12k (FPC relief hole) is formed on the barrel portion 12p to the rear of the FPC fixing part 12m.

The FPC relief hole 12k is formed parallel to the optical axis 0 and is sufficiently large to allow the flexible printed circuit board 6 to protrude outward.

The fixing part 12m is provided with a plurality of fixing protrusions 12n and the flexible printed circuit board 6 is attached to the fixing part 12m by fitting a plurality of fixing holes 6i (see, for example, Fig. 13) over the plurality of fixing protrusions 12n.

In order to guide the flexible printed circuit board 6, the rectilinear guide barrel 17 further includes, on its inner peripheral face, a flexible printed circuit board lead-in groove 17h (FPC lead-in groove), which runs parallel to the optical axis 0 and guides the flexible printed circuit board 6 (see Fig. 19). The FPC lead-in groove 17h includes a through hole 17i that passes through the linear guide barrel 17 at the rear of the FPC lead-in groove 17h.

Also, to guide the flexible printed circuit board 6, the annular part 22a further includes a guide groove 22i, which allows the passage of and rectilinearly guides the flexible printed circuit board 6 (see Fig. 19). The annular part 22a also supports a spring support part 70, which resiliently supports the flexible printed circuit board 6.

As shown in Figs. 20 and 21, the spring support part 70 includes two guiding protrusions 70c, which protrude toward the front of the camera, a spring bearing protrusion 70a, which is positioned between the two guiding protrusions 70c, and a spring housing groove 70b, which is provided at the base of the spring bearing protrusion 70a, see Fig. 21.

The rear face of the linear guide member 22 includes two sliding support holes 22h and a spring hole 22g, which is positioned between the two sliding supporting holes 22h.

The two guiding protrusions 70c are slidably fitted into the two sliding supporting holes 22h. A compression spring 71 is placed on the spring bearing protrusion 70a and is supported in the spring housing groove 70b. The spring bearing protrusion 70a is then inserted into the spring hole 22g and the spring 71 is compressed inside the spring hole 22g. The spring support part 70 also includes a guide groove 70d that substantially coincides with the guide groove 22i when the spring bearing protrusion 70a is inserted into the spring hole 22g.

With the above arrangement, the spring support part 70 is positioned at the rear of the linear guide member 22 (i.e. the rear of the first movable barrel 20) such that the flexible printed circuit board 6 is resiliently supported in a direction parallel to the optical axis 0.

Further, the retaining member 33 that is fixed at the front of the fixed lens barrel block 12 includes a stopping protrusion 33a, which engages with the front end of the fixed lens barrel block 12, and a restricting protrusion 33g, which fits into the FPC relief hole 12k from the front side (see Fig. 12). The restricting protrusion 33g guides the flexible printed circuit board 6 and restricts the rotation of the retaining member 33 with respect to the barrel part 12p of the fixed lens barrel block 12.

The flexible printed circuit board 6 connects the AF/AE shutter unit 21 with a control unit 75 (see Fig. 8) that is mounted on the camera body. The control unit 75 includes, for example, a CPU (not shown), the AE motor controller 66, the whole optical unit driving motor controller 60, the rear lens group driving motor controller 61, the object distance measuring apparatus 64, and the photometering apparatus 65.

The control unit 75 is also connected to, for example, the zoom operating device 62 and the focus operating device 63.

The flexible printed circuit board 6 is defined as including a number of segments as follows. A first rectilinear segment 6a, which extends from the AF/AE shutter unit 21 to the rear of the linear guide member 22; a first U-shaped segment 6b, which is formed by inserting the flexible printed circuit board 6 into the guide groove 22i at the rear of the rectilinear guide member 22 and bending the flexible printed circuit board 6 back towards the front over the spring support part 70; a second rectilinear segment 6c, which extends frontward along the FPC lead-in groove 17h; a second U-shaped segment 6d, which is formed by bending the flexible printed circuit board 6 toward the rear around the front end of the FPC lead-in groove 17h; a third rectilinear segment 6e, which extends rearward along an outer face 17j of the FPC lead-in groove 17h (within the inner face of the third movable barrel 16) and, near the rear end of the FPC lead-in groove 17h is lead to the inner face of the rectilinear guide barrel 17 via the through hole 17i; a third U-shaped segment 6f, which is formed to pass the flexible printed circuit board 6 through the FPC relief hole 12k of the fixed lens barrel block 12; a fourth rectilinear segment 6g, which extends from the third Ushaped segment 6f; and a fixed end segment 6h, which is fixed to the fixed part 12m at the outer side of the fixed lens barrel block 12 (see, in particular Figs. 8 and 9).

Further, the third rectilinear segment 6e of the flexible printed circuit board 6 is secured to the outer face 17j of the linear guide barrel 17 by, for example, double-coated tape 73 (Fig. 19).

In other words, the flexible printed circuit board 6 is lead rearward from the AF/AE shutter unit 21 on the inner side of the second movable barrel 19, bent forward once at the rear end of the second movable barrel 19, lead forward inside the FPC lead-in groove 17h of the linear guide barrel 17, bent backward along the outer face 17j of the linear guide barrel 17 from the front end of the FPC lead-in groove 17h, is adhered to the outer face 17j with the double-sided tape 73, is guided again to the inner face of the rectilinear guide barrel 17 via the through hole 17i, and is then bent out through the FPC relief hole 12k and attached to the fixing part 12m of the fixed lens barrel block 12.

Since the flexible printed circuit board 6 is fixed to the linear guide barrel 17 by the double-coated tape 73, when the linear guide barrel 17 extends from the barrel part 12p of the fixed lens barrel block 12, the third U-shaped segment 6f of the flexible printed circuit board 6 will be slack and may obstruct light passing through the camera (as shown by the dashed lines in Fig. 14).

In the present embodiment, the flexible printed circuit board 6 slack is stored in the otherwise unused space ("dead space") occurring around a cartridge chamber (for holding the camera film) or a spool chamber (for holding the windup spool for winding the film from said cartridge chamber).

Referring to Fig. 14, in particular, the fixed lens barrel block 12 is fixed to a camera body 79. The camera body 79 is provided with an integral cartridge chamber (or spool chamber) 80 and the aperture plate 14. The third movable barrel 16 is screwed into the barrel part 12p as shown in Fig. 13. With this arrangement, a space is created by a rounded outer wall face 80a of the cartridge chamber 80, an outer wall face 12q of the barrel part 12p, and a rear surface of the fixed part 12m of the fixed lens barrel block 12. This space, referred to as dead space" because it is otherwise unused, is used as an FPC housing space 81 to store the slack of the flexible printed circuit board 6.

In order to make efficient use of the FPC housing space 81, the flexible printed circuit board 6 is fed into and out of the FPC housing space 81 such that the length of the flexible printed circuit board 6 is perpendicular to the axis of the cartridge chamber 80 (parallel to the optical axis) or is wrapped against the rounded outer wall face 80a of the cartridge chamber 80. This arrangement is more efficient than, for example, the case where the flexible printed circuit board 6 is fed into and out of the FPC housing space obliquely with respect to the axis of the cartridge chamber 80.

In order to draw the flexible printed circuit board 6 into the FPC housing space 81, the FPC housing space 81 is provided with a spring mechanism 84 which pulls the flexible printed circuit board 6 inside the housing space 81. In particular, the spring mechanism 84 pulls the flexible printed circuit board 6 in a direction that is perpendicular to the optical axis 0. Alternatively, a compression spring (not shown) could be used to push the flexible printed circuit board 6 into the housing space 81.

The spring mechanism 84 includes a tension spring 82 and a spring bearing pin 83. As shown in Fig. 16, the spring bearing pin 83 includes a contacting part 83a, and a spring hooking part 83b, which is positioned at substantially the centre of the contacting part 83a. Further, the fourth rectilinear part 6g of the flexible printed circuit board 6 is formed with a lengthwise slot 6j (see Fig. 15) at a position that is near to the fixed end segment 6h, but inside the FPC housing space 81.

The tension spring 82 is hooked at one end to an anchoring protrusion 12s that is provided on the fixed part 12m, and at the other end to the spring hooking part 83b of the spring bearing pin 83. As shown in Fig. 16, the contacting part 83a has a width which is slightly less than the width of the slot 6j such that the contacting part 83a is insertable through the slot 6j to be positioned perpendicular to the lengthwise direction of the flexible printed circuit board 6. Thus, the tension spring 82 applies a force to the flexible printed circuit board 6 pulling the fourth rectilinear segment 6g into the FPC housing space 81.

The slack of the flexible printed circuit board 6 at the third U-shaped part 6f and the fourth rectilinear part 6g is thus pulled into and fed out of the FPC housing space 81 during the movement of the linear guide barrel 17.

Further, with this arrangement, since the spring bearing pin 83 pulls the fourth rectilinear part 6g while sliding along the slot 6j, the spring force is applied over a broader region and the spring extends by only a small amount.

Thus, with the present FPC housing structure, the slack in the flexible printed circuit board 6 is stored in the otherwise unused space (dead space") formed by the rounded outer wall face 80a of the cartridge chamber (or spool chamber) 80 and the outer wall face 12q and the fixed part 12m of the barrel part 12p so that the camera can be made compact. Furthermore, since the spring mechanism 84 only requires two parts (the tension spring 82 and the spring bearing pin 83), the FPC housing structure is easily assembled.

Although the structure and operation of a flexible printed circuit board housing structure is described herein with respect to the preferred embodiments, many modifications and changes can be made, the details of which will be readily apparent to a person skilled in the art.

Claims

1. A camera body comprising: a stationary housing for slidably locating a barrel therein to move along the optical axis; a film chamber for holding film, the film chamber being located adjacent said stationary housing and wherein a space is defined between a wall of said film chamber and a wall of said housing; and a relief hole formed in said housing to open into said space for enabling a flexible printed circuit board to pass through said relief hole so that a portion of said flexible printed circuit board is capable of being housed in said space.

2. A camera body according to claim 1 wherein said space for housing said portion of the flexible printed circuit board has a curved surface; wherein said curved surface is located such that the housed portion of the flexible printed circuit board curves around said curved surface.

3. A camera body according to claim 1 or 2 wherein said stationary barrel is formed to provide a range of movement of said movable barrel; and wherein said relief hole is formed at a position which is substantially a middle point of said range of movement of said movable barrel.

4. A camera body according to any preceding claim wherein said film chamber is either a cartridge chamber for storing unexposed film or a wind-up chamber for storing exposed film.

5. A combination of a camera body according to any preceding claim and a spring means; wherein the spring means is provided in said space to urge said portion of the flexible printed circuit board into the space.

6. A combination according to claim 5 wherein said spring means is located to urge said portion of the flexible printed circuit board in a direction perpendicular to said optical axis.

7. A combination according to claim 5 or 6 wherein said spring means includes a slidable attachment capable of slidably attaching to said portion of the flexible printed circuit board.

8. A combination according to claim 7 wherein said slidable attachment comprises a spring bearing pin to be attached to a slot in said portion of the flexible printed circuit board.

9. A combination according to any one of claims 5 to 8 further comprising said flexible printed circuit board.

10. A combination according to claim 9 wherein said flexible printed circuit board extends from said movable barrel, around a rear end of the movable barrel, and extends into said space.

11. A combination according to claim 10 wherein a part of said flexible printed circuit board is fixed externally of said space, and another part of said flexible printed circuit board is fixed to said movable barrel.

12. A combination according to any one of claims 9 to 11 wherein a slot of predetermined length is formed lengthwise on a part of said portion of flexible printed circuit board located inside said space.

13. A camera body in combination with a spring means, wherein the camera body comprises a stationary housing for slidably locating a barrel therein to move along the optical axis; and wherein the spring means is provided externally of said housing for urging a portion of a flexible printed circuit board in a direction laterally of said optical axis.

14. A combination according to claim 13 wherein said spring means is provided for urging said portion of the flexible printed circuit board perpendicular to said optical axis.

15. A combination according to claim 13 or 14 further comprising said movable barrel and said flexible printed circuit board; wherein said portion of said flexible printed circuit board extends from said movable barrel, around a rear end of the movable barrel, and extends to the exterior of said housing.

16. A camera body substantially as herein described with reference to figures 12 to 21.