GB2347518A

GB2347518A - Zoom compact camera with flexible circuit board

Info

Publication number: GB2347518A
Application number: GB0009891A
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: 2000-09-06
Anticipated expiration: 2017-01-24
Also published as: GB0009891D0; GB2347519B; GB2347518B; GB0009893D0; GB2347519A

Abstract

A zoom compact camera has a first barrel (20), which carries a shutter unit (40), arranged to telescope relative to a second barrel (19). A linear guide barrel (17) moves integrally with the second barrel (19) and is provided on the inner surface with a lead-in groove (17h). The rear of the lead-in groove (17h) includes a through hole (17i) that passes through the linear guide barrel 17. A flexible printed circuit board (6) for electrically connecting a control unit to said shutter unit is provided. The flexible printed circuit board (6) extends around the rear of the first barrel (20), extends forwardly inside the lead-in groove (17h), extends around the front end of the lead-in groove (17h), extends rearwardly along an outer face of the linear guide barrel (17), and then extends through the through hole (17i) to the inner face of the linear guide barrel (17).

Description

ZOOM COMPACT CAMERA The present invention relates to a zoom compact camera.

In a lens-shutter type of camera having a zooming function ("zoom compact camera"), a lens barrel, and, in particular, a zoom lens barrel, is often provided with at least one movable barrel that moves away from and toward the camera along the optical axis. If an electrical unit, such as a shutter unit, is housed in the movable barrel, the shutter unit must be connected to the camera in order to receive control signals. Thus, the lens barrel is provided with a flexible printed circuit board (FPC) between the shutter unit and the camera to allow movement of the movable barrel with respect to the camera. However, a problem arises in that, as the movable barrel moves toward the camera, the flexible printed circuit board becomes slack and can interfere with the movement of the barrels or with the light coming through the camera aperture.

One conventional measure to deal with the above problem is to provide an area for taking up and paying out the slack part of the flexible printed circuit board. However, this method requires an extra mechanism for taking up or paying out the slack, or requires extra space for storage of the slack.

Another measure is to provide a flexible printed circuit board that is formed with a spiral spring-like shape that is arranged around the inner diameter of the lens barrel such that as the movable barrel extends the flexible printed circuit board expands like a spring, and as the movable barrel retracts, the flexible printed circuit board also retracts like a spring being compressed. However, this method requires that the lens barrel have a diameter that is sufficient to accommodate the flexible printed circuit board such that the flexible printed circuit board does not interfere with the light coming through the camera aperture.

It is therefore an object of the present invention to provide an improved zoom compact camera in which an electrical unit in a movable barrel can be electrically connected to a control unit at the camera body in a simple and compact way.

According to one aspect of the invention there is provided a zoom compact camera that includes a camera body, a first movable barrel, a second movable barrel, a housing, an electrical unit (such as a shutter unit) mounted on the first movable barrel, and a flexible printed circuit board for connecting the electrical unit with a control unit at the camera body.

The first movable barrel and the second movable barrel are concentrically arranged to telescope during zooming and the housing guides the second movable barrel. The flexible printed circuit board is arranged such that it extends with a predetermined length from said electrical unit around a rear end of said second movable barrel to the front of said housing.

The camera is further arranged such that, during movement of the first movable barrel, the second movable barrel, and the third movable barrel, the relative amount and speed of movement along the optical axis of the first movable barrel with respect to the second movable barrel are set to be substantially equal to the relative amount and speed of movement along the optical axis of the second movable barrel with respect to the housing.

If the movable barrels move in this exemplary manner, the shape of the flexible printed circuit board adjusts without slacking. That is, as the shutter unit moves forward with the movement of the first movable barrel the flexible printed circuit board is pulled forward. However, since the first movable barrel is moving relative to the second movable barrel at the same rate that the second movable barrel is moving relative to the housing, an equivalent amount of the flexible printed circuit board is fed from the part of the flexible printed circuit board that runs between the second movable barrel and the housing. Thus, any slacking of the flexible printed circuit board is prevented and there is no need to provide a receiving part for receiving the slack, thus providing a more compact camera.

In particular, if a spring support is provided at the rear end of the second movable barrel, such that the spring support supports the flexible printed circuit board and urges the flexible printed circuit board rearward, the flexible printed circuit board will be guided with no slack.

Alternatively, where the second movable barrel houses a linear guide member that moves integrally with the second movable barrel along the optical axis, the linear guide member may be provided with the spring support.

In a particular exemplary structure, the housing is formed as a third movable barrel that houses a linear guide barrel that moves integrally with the third movable barrel along the optical axis. The linear guide barrel is provided on an inner face thereof with a lead-in groove that extends parallel to the optical axis for receiving the flexible printed circuit board. The use of a lead-in groove ensures that the flexible printed circuit board does not interfere with the movements of various parts in the lens barrel.

In another exemplary structure, a through hole is formed at a rear part of the lead-in groove, and a portion of the flexible printed circuit board is arranged such that it extends around a rear end of the second movable barrel, extends forwardly inside the lead-in groove, extends around a front of said lead-in groove, extends rearwardly along an outer face of said linear guide barrel, and extends through said through hole to the inner face of said linear guide barrel. This arrangement further secures the flexible printed circuit board in position to ensure that the flexible printed circuit board does not interfere with the movement of various parts in the camera and minimizes the amount of space used by the flexible printed circuit board.

Preferably, in all of the above noted exemplary structures, the movement speeds of the first movable barrel and the second movable barrel are respectively varied in a linear manner.

Also, in all of the above exemplary structures, the flexible printed circuit board may be secured at or near the front of the housing, and, may be secured to the housing (the third movable barrel) or the outer face of the linear guide barrel by, for example, double-sided tape.

In another preferred embodiment, the zoom compact camera includes a camera body, a movable lens barrel, an electrical unit (such as a shutter unit), a flexible printed circuit board for providing an electrical link between the electrical unit and a control unit at the camera body, and a fixed lens barrel that supports the movable lens barrel in a manner enabling movement of the movable lens barrel along the optical axis.

In particular, the flexible printed circuit board has at least one annular ring portion with a predetermined inner diameter.

In a preferred arrangement, the annular ring portion includes two annular rings that have an electrical connection at a first position on a circumferential edge thereof. In this case, the two annular rings are attached at one side but can separate at an opposite side such that the annular rings expand and contract in a bellows-like manner when the movable lens barrel moves forward and rearward, respectively, along the optical axis.

With this arrangement, the two annular rings fold and unfold in coordination with the movement of the movable barrel such that there is no slack in the flexible printed circuit board. Further, the use of an annular arrangement allows circuit patterns in the flexible printed circuit board to be split into two paths around the semi-circular halves of the annular portion such that the width of the annular portion is half of the width of the other portions of the flexible printed circuit board. Thus, the annular portion does not interfere with the light entering the camera aperture.

In a particular exemplary structure, the flexible printed circuit board may further include a first rectilinear part and a second rectilinear part. The first rectilinear portion having an electrical connection to one of the two annular rings at a second position opposite to said first position and the second rectilinear portion having an electrical connection to the other of the two annular rings at a corresponding third position on the other of the two annular rings. With this arrangement, the two annular rings are supported by the first rectilinear portion and the second rectilinear portion and are folded and unfolded, as described above, by the movement of the first rectilinear portion and the second rectilinear portion.

Examples 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 exploded perspective view showing the major parts of a flexible printed circuit board guiding structure of the zoom lens barrel; Fig. 13 is an enlarged perspective view showing the rectilinear guide member of the zoom lens barrel; Fig. 14 is a cross-section showing a spring support at an end of the rectilinear guide member of the zoom lens barrel; Fig. 15 is an external perspective view showing the condition of the flexible printed circuit board of the first embodiment in relation to the first movable barrel; Fig. 16 is an external perspective view showing the condition of the flexible printed circuit board of the first embodiment in relation to the second movable barrel; Fig. 17 is an external perspective view showing the condition of the flexible printed circuit board of the first embodiment in relation to the rectilinear guide barrel; Fig. 18 is an external perspective view showing the condition of the flexible printed circuit board of the first embodiment in relation to the third movable barrel; Fig. 19 is an external perspective view of a fixed lens barrel block of the zoom lens barrel; Fig. 20 is a front view of the fixed lens barrel block of the zoom lens barrel; Fig. 21 is a rear view of the fixed lens barrel block of the zoom lens barrel; Fig. 22 is a development of the rectilinear guide barrel of the zoom lens barrel; Fig. 23 is an enlarged development of major parts of the rectilinear guide barrel of the zoom lens barrel; Fig. 24 is a development of the second movable barrel of the zoom lens barrel; Fig. 25 is an enlarged development of major parts of the second movable barrel of the zoom lens barrel; Fig. 26 is a graph showing the correlation between the rotation angle of the third movable barrel of the zoom lens barrel and the respective amounts of extensions of the first and second movable barrels of the zoom lens barrel; Fig. 27 is a sectional view of an upper part of the zoom lens barrel in a maximum extended state showing the flexible printed circuit board of the second embodiment ; Fig. 28 is a sectional view of an upper part of the zoom lens barrel in a housed state showing the flexible printed circuit board of the second embodiment; Fig. 29 is a plan view of the flexible printed circuit board of the second embodiment; and Fig. 30 is a perspective view of the flexible printed circuit board of the second embodiment.

Preferred Embodiments of a lens-shutter type of camera having a zooming function (referred to as a"zoom compact camera"or a"zoom lens camera") will be described below.

Common parts in the figures bear common reference numerals.

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 0. In the zoom lens barrel 10, two lens groups are provided, namely a front lens group Li 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 Li and the rear lens group L2, rearwardly or forwardly. In the following explanation, forward and rearward movements of the lens groups LI 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 LI 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 LI 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 LI 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 Li 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 O 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 O, with the third movable barrel 16 rotating relative to the linear guide barrel 17. The first movable barrel 20 moves along the optical axis O with rotation thereof being restricted. The second movable barrel 19 moves along the optical axis O, 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 LI 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 O, 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 31a 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 17c each projecting away from the optical axis O 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 O 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 17c with the corresponding linear guide grooves 12b, formed parallel to the optical axis O.

A contacting terminal 9 is fixed to one of the engaging projections 17c, namely 17cl. 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 O.

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 O 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 O 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 O as a whole, and in addition are capable of relatively rotating around the optical axis O. 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 19b 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 19b, 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 19b 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 O, 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 19c, 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 formed slits provided in the circumferential direction. An encoder for detecting whether the rear lens group driving motor 30 is rotating and for detecting an amount of rotation of the rear lens group driving motor 30 comprises the photointerrupter 57 and the 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 O 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 LI 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 LI 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 O. 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 O 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 O 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 LI 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 LI 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 LI and the rear lens group L2 to the respective initial positions which they were at prior to a shutter release.

A first embodiment of a zoom compact camera having a flexible printed circuit board guiding structure is now described with reference to Figs. 8,9, and 12-26.

As shown in Figs. 12 and 19, 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 supporting part 32 supports at the rear thereof the whole optical unit driving motor 25 and at the front thereof a gear train 26 comprising a plurality of gears as shown in Fig. 10.

The FPC fixing part 12m is formed projecting sideways 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 O 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. 15) to the plurality of fixing protrusions 12n.

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.

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 O and guides the flexible printed circuit board 6. 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, as shown in Fig. 13, the annular part 22a further includes a guide groove 22i, which allows the passage of and rectilinearly guides the flexible printed circuit board 6.

In Fig. 13, the flexible printed circuit board is shown using phantom lines to show its position in the guide groove 22i.

The annular part 22a also supports a spring support part 70, which resiliently supports the flexible printed circuit board 6. 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. 14.

As shown in 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 is compressed inside 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 O.

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 (see, for example, Fig. 13) 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 rectilinear guide barrel 17 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 U-shaped 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. 15-18).

Further, the flexible printed circuit board 6 is fixed with respect to the linear guide barrel 17 by securing the third rectilinear segment 6e to the outer face 17j of the linear guide barrel 17 by, for example, double-coated tape 73 (Fig. 12).

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, is bent forward once at the rear end of the second movable barrel 19, is lead forward inside the FPC lead-in groove 17h of the linear guide barrel 17, is bent backward along the outer face 17j of the linear guide barrel 17 from. the front end of the FPC lead-in guide 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.

The fixed end segment 6h of the flexible printed circuit board 6 is connected to the control unit 75 via a second flexible printed circuit board (not shown) to make the connection to the control unit 75 shown by a dotted line in Fig. 8.

As described above, the flexible printed circuit board 6 is bent rearward at the front end of the FPC lead-in groove 17h and is then lead along the outer face 17j of the rectilinear guide barrel 17 until it is lead into the inner face of the rectilinear guide barrel 17 via the through hole 17i. Since the flexible printed circuit board 6 is held in place and guided by the FPC lead-in groove 17h on the inner side of the linear guide barrel 17 and is prevented from moving radially on the outer face 17j of the linear guide barrel 17 because it is lead through the through hole 17i, the flexible printed circuit board 6 will not interfere with the follower pin 18, which moves in and is guided by the lead groove 17b, or interfere with the movement of the second movable barrel 19 or the third movable barrel 16.

In the present embodiment, the relative distance of movement and the speed of movement of the first movable barrel 20 with respect to the second movable barrel 19 in the optical axis direction during zooming (advancing/retracting movement along the optical axis O) is set substantially equal to the relative distance of movement and speed of movement of the second movable barrel 19 with respect to the third movable barrel 16. The substantial equality is achieved by setting the engaging relationship between the third movable barrel 16 and the fixed lens barrel block 12, the inclination (lead angle) of the lead groove 17b on the rectilinear guide barrel 17, and the inclination (lead angle) of the lead groove 19c on the second movable barrel 19. Note that, the third movable barrel 16 of this embodiment could also be a stationary portion, such as a housing for guiding the second movable barrel 19.

In particular, as a non-limiting exemplary arrangement of a preferred embodiment, the amount of lead of the lead groove 19c (i. e. the amount by which the first movable barrel 20 moves) is set to 124mm and the amount of lead of the lead groove 17b (i. e. the amount by which the second movable barrel 19 moves) is set to 122.5mm. As shown in Figs. 22-25, the lead grooves 19c and 17b include linear portions with a fixed lead angle and slip groove parts 19c' and 17b'that are orthogonal to the optical axis 0 and that correspond to the lens accommodation position.

With the above arrangement, the respective amounts of extension of the first movable barrel 20 and the second movable barrel 19 are proportional to the amount of rotation of the third movable barrel 16 (and the speed of movement is proportional to the rotation speed of the whole optical unit driving motor 25). In both the linear guide barrel 17 and the second movable barrel 19, the lead starting points for extending the first movable barrel 20 and the second movable barrel 19 are hypothetical points at a position 3 from the lens-housed position when the follower protrusion 19a and the follower pin 24 are respectively positioned at the slip groove parts 17b'and 19c'.

Actually, the rectilinear guide barrel 17 does not rotate, but because the third movable barrel 16 does rotate, the relative rotation of the rectilinear guide barrel 17 with resp the follower pin 24 from the hypothetical starting points to the positions corresponding to the position at which the zoom lens is extended the most (tele end). Thus, the extension amount difference in the relative amounts of extension of the first movable barrel 20 and the second movable barrel 19, in the exemplary arrangement above, is: (124-122.5) X 70/360 z 0.3 mm The extension amount difference is compensated for by the spring support part 70. In particular, since the first U-shaped segment 6b at the rear end of the second movable barrel 19 (and the linear guide member 22) is wound around the spring support part 70, the amount of compensating movement required by the spring support part 70 in the optical axis direction is half of the actual extension amount difference, that is, for the exemplary arrangement, 0.15 mm. Thus, when the first rectilinear segment 6a of the flexible printed circuit board 6 is pulled in the optical axis direction by the first movable barrel 20 by the above extension amount difference of 0.3 mm, the spring support part 70 is moved in the optical axis direction by 0.15 mm.

That is, the spring support part 70, which is supported and urged rearward by the compression spring 71, is adjusted to allow movement by 0.15 mm forward in the optical axis direction. over this distance, the percentage change in the urging force of the compression spring 71 is set to approximately 10%.

Fig. 26 is a graph showing the relationship between the amount of rotation of the third movable barrel 16 and the relative amount of advance/retraction (amount of extension) of the first movable barrel 20 with respect to the second movable barrel 19 and the relative amount of advance/retraction (amount of extension) of the second movable barrel 19 with respect to the third movable barrel 16 for the exemplary arrangement. As can be seen in this graph, the respective advancing/retracting motions along the optical axis O, of the first movable barrel 20 and the second movable barrel 19 vary linearly. In other words, other than in the range of 0 -3 , the respective amounts of movement of the first movable barrel 20 and the second movable barrel 19 are proportional to the amount of rotation of the third movable barrel 16. The range from 0 -3 corresponds to the movement from the lens-housed position to the lead starting points (discussed above, and shown in Figs. 23 and 25, that is, the curved parts 19c3 and 17b3, which connect the respective horizontal parts 19cl and 17bl and the lead parts 19c2 and 17b2 of the lead grooves 19c and 17b). The point of transition from the curved part to the lead part corresponds to a rotation angle of 4.367 for the lead groove 19c and to a rotation angle of 4.848 for the lead groove 17b in the above example.

Since the first movable barrel 20 and the second movable barrel 19 are substantially equal with regard to the amount of extension for the same amount of rotation of the third movable barrel 16 (in other words, for the same time) and their respective advancing/retracting motions vary linearly, it can be understood that, during advance or retraction (during zooming), the relative amount and speed of advance/retraction along the optical axis O of the first movable barrel 20 with respect to the second movable barrel 19 is substantially equal to the relative amount and speed of advance/retraction along the optical axis O of the second movable barrel 19 with respect to the third movable barrel 16. In the above, the term"substantially equal"means that the error between the relative amount and speed of advance/retraction along the optical axis O of the first movable barrel 20 with respect to the second movable barrel 19 and the relative amount and speed of advance/retraction along the optical axis O of the second movable barrel 19 with respect to the third movable barrel 16 is approximately + 0. 3%.

As explained above, when the zoom lens barrel 10 is advanced or retracted, the relative movements of the first movable barrel 20 and of the second movable barrel movable barrel 19 prevent slack in the flexible printed circuit board 6. In particular, as shown in Fig. 9, initially, the first linear segment 6a is short, while the second linear segment 6c is long, then, during advance, the lengths of the first linear segment 6a and the second linear segment 6c vary proportionally such that at full extension, as shown in Fig. 8, the first linear segment 6a is long, while the second linear segment 6c is short. During this advance, the first U-shaped segment 6b remains in contact with the spring support part 70 and, as explained above, the spring support part 70 is resiliently mounted to compensate for any slack in the flexible printed circuit board 6 that is not controlled by the relationship of the movements of the first movable barrel 20 and the second movable barrel 19. The process is reversed during retracting.

Thus, in the present embodiment of the zoom compact camera, slack in the flexible printed circuit board 6 is prevented and a receiving part for receiving any slack is not needed allowing a more compact camera. Further, by the combination of the FPC lead-in groove 17h and the through hole 17i, the flexible printed circuit board 6 is held in position such that the flexible printed circuit board 6 does not affect or interfere with the movement of the components of the camera.

Another preferred embodiment of the zoom compact camera will now be described with reference to Figs. 27 to 30. In this embodiment, the flexible printed circuit board 6 can be described as including a number of segments, as follows: a first rectilinear segment 6a, which extends along the inner face of the second movable barrel 19 from the AF/AE shutter unit 21 mounted on the first movable barrel 20 to the rear of the linear guide member 22; a first U-shaped segment 6b, which is formed by bending the flexible printed circuit board 6 forward over the spring support part 70 and inserting the flexible printed circuit board 6 into the lead-in groove 17h at the rear of the linear guide barrel 17; a second rectilinear segment 6c, which extends frontward along the inner face of the lead-in groove 17h towards the front end of the third movable barrel 16; 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 on the linear guide barrel 17; a third rectilinear segment 6e, which extends rearward along the outer face 17j of the FPC lead-in groove 17h (between the inner face of the third movable barrel 16) toward the camera body, and is lead to the inner face of the rectilinear guide barrel 17 via the through hole 17i; a pair of annular segments 6fl and 6f2 described in detail below; a fourth rectilinear segment 6g, which extends from the annular segment 6f2 along the exterior of the fixed lens barrel block 12; 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.

As in the previous embodiment, the flexible printed circuit board 6 is fixed to the outer face 17j of the linear guide barrel 17 by the double-coated tape 73. Also, the fixed end segment 6h of the flexible printed circuit board 6 is connected to the control unit 75 via a second flexible printed circuit board (not shown).

In particular, the annular segments 6fl and 6f2 define holes hl and h2 which allow the passage of the photographing light (the light of the photographing optical system). As shown in Figs. 29 and 30, the annular segments 6fl and 6f2 iorm a"spectacle-like"form in the unfolded condition and are foldable at the middle at a joining segment 6h. The annular segment 6fl is attached to the third rectilinear segment 6e and the annular segment 6f2 is attached to the fourth rectilinear segment 6g. In particular, the annular segment 6f2 attaches to the fourth rectilinear segment 6g through a gap between the rear end of the fixed lens barrel block 12 and the aperture plate 14 such that the through hole 12k described for the first embodiment is not required.

If, for example, the flexible printed circuit board 6 is further provided with circuit patterns PI and P2 (shown in Fig. 29), which continue over the whole length of the flexible printed circuit board 6 (not shown), the patterns P1 and P2 can be split to the left and right sides of the annular segments 6fl and 6f2 as shown in Fig. 29. The arrangement of the annular segments 6fl and 6f2 in this manner provides a structure which expands and retracts between a closed position as shown in Fig. 28 and an opened position as shown in Fig. 27. That is, the annular segments 6fl and 6f2 extend and retract in a bellows-like manner (when viewed from the side of the zoom lens barrel 10) as the first movable barrel 20 advances and retracts along the optical axis O.

In particular, the use of a combination of circuit patterns P1 and P2 allows the widths (i. e. difference between outer diameters and inner diameters) of the annular segments 6fl of 6f2 to be smaller than the width of the other segments of the flexible printed circuit board 6 and, moreover, smaller than the width of a single flexible printed circuit board arranged in a spiral manner, thus taking less space within the camera. Furthermore, since the photographing light passes through the holes hl and h2 of the annular parts 6fl and 6f2, both adverse light rays at the edges of the photographing light beam and internal reflection will be reduced.

Although the structure and operation of a zoom compact camera is described herein with respect to the preferred embodiments and exemplary structures, 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 zoom compact camera comprising: a camera body having a control unit therein; a first movable barrel concentrically arranged to telescope along the optical axis relative to a second movable barrel; a linear guide barrel that moves integrally with said second movable barrel along the optical axis, the inner face of said linear guide barrel having formed thereon a lead-in groove parallel to the optical axis and said lead-in groove has a through hole formed at a rear part thereof; an electrical unit carried by a telescoping barrel other than said second barrel; a flexible printed circuit board for electrically connecting said control unit to said electrical unit, said flexible printed circuit board extending around a rear end of said first movable barrel, extending forwardly inside said lead-in groove, extending around a front end of said lead-in groove, extending rearwardly along an outer face of said linear guide barrel, and extending through said through hole to the inner face of said linear guide barrel.

2. A camera according to claim 1 further comprising another movable barrel concentrically arranged to telescope along the optical axis relative to said first movable barrel; said electrical unit being carried by said another movable barrel.

3. A camera according to claim 2 further comprising a controller for controlling the distance and speed of telescoping movement of said another movable barrel relative to said first movable barrel to be substantially equal to the distance and speed of telescoping movement of said first barrel relative to said second movable barrel.

4. A camera according to claim 3 wherein the controller varies the speed of telescoping movement of said first movable barrel and second movable barrel in a linear manner.

5. A camera according to any one of claims 1 to 4 wherein said first movable barrel further comprises a linear guide member that moves integrally with said first movable barrel along the optical axis; the camera further comprising a spring support disposed at the rear end of linear guide member for urging said flexible printed circuit board away from said linear guide member.

6. A camera according to any one of claims 1 to 5 wherein said flexible printed circuit board is secured at or near the front of said first barrel.

7. A camera according to claim 6 wherein said flexible printed circuit board is secured by double-sided tape.

8. A camera according to any one of claims 1 to 7 further comprising a housing for guiding said linear guide barrel; wherein said flexible printed circuit board extends from said control unit through a relief hole in said housing to said through hole formed at a rear part of said linear guide barrel.