Encoder, lens-implement and digital camera

All members of a lens-implement are arranged in a rectangular space of a main lens frame. A lens prism is fixed, three movable lens frames for zoom and focusing inserted the two guide shafts are arranged, and a image capturing lens is fixed top-to-bottom seriatim occupying the horizontal ⅔ portion of the rectangular space, and the image capturing device is arranged at foot portion. A zoom motor is arranged at the back of the lens prism, and a zoom shaft cam, a diaphragm/shutter, a focusing ultrasonic linear motor, and a magnetic sensor are arranged along the lens frames.

CROSS REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority from the prior Japanese Application No. 2003-172159, No. 2003-172142, No. 2003-172154, No. 2003-172169, filed Jun. 17, 2003, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a simple architectonics high-precision encoder, a slim lens-implement using the encoder, and a digital camera using the lens-implement.

2. Description of the Related Art

Conventionally, with a growing demand for a smaller and slimmer digital camera in the digital camera market, a slim lens-implement incorporated into a digital camera has been required.

As one of the methods of providing a slimmer lens-implement, a lens-implement based on a bent-optical-axis optical system has been proposed. For a slimmer device, the Applicant has proposed a lens-implement configured by arranging in parallel a plurality of units forming a lens-implement (for example, a patent literature 1).

For a lens-implement based on the slimmer and bent-optical-axis optical system, an electronic zoom is not demanded in the recent digital camera market, but a request for an optical zoom is growing. Therefore, a lens-implement of a bent-optical-axis optical system having a built-in optical zoom has been proposed. (For example, refer to Japanese Patent Application Laid-open No. 2003-066309, abstract, FIGS. 3 and 5; Japanese Patent Application Laid-open No. 2002-290806, claim6, paragraphs [0038] and [0041], FIGS. 2 and 3.) In the lens-implement of a conventional camera, a lens frame unit holding a lens for a zoom and focusing is freely transferred in the optical axis direction at an instruction from a control device.

Since a lens frame unit and a drive unit for driving the lens frame unit are individually manufactured, a coupling mechanism is required to transmit a driving force to transmit the driving force of the drive unit to the lens frame unit.

In this case, it is necessary to amend various displacements such as the displacement between the units, the displacement in the horizontal direction relative to the lens frame unit, etc. However, there have been the methods for coupling the units with the above-mentioned displacements easily absorbed and amended. Among them, for example, there is a configuration proposed in which a spring member that indicates elastic deformation is used for a coupling member, and the spring member has the elasticity allowing a deformation on the plane normal to the optical axis or perpendicular to the optical axis while the spring member has no elasticity in the optical axis direction. (For example, refer to Japanese Patent Application Laid-open No. Hei 09-061692, paragraph [0018], FIG. 1, and Japanese Patent Application Laid-open No. Hei 09-033782, abstract, and FIG. 1.)

As a type of encoder for continuously detecting the position, a position detection device using a magnetic resistance element is proposed. The position detection device is a high-precision, possible down sizing and capable of easily consecutive detecting transfer positions, and therefore is specifically used in detecting an amount of transfer of a lens.

In the meantime, the position detection device using the magnetic resistance element has the problem that a magnetic sensor cannot correctly read the magnetic scale unless the magnetic resistance element (magnetic sensor) and the magnetic scale can be maintained at a predetermined interval.

Accordingly, there has been the position detection device proposed by providing a simple adjusting mechanism to maintain a constant interval between the magnetic sensor and the magnetic scale (for example, see Abstract of the Disclosure, and FIG. 1 of Japanese Patent Application Laid-open No. 2000-002559.)

SUMMARY OF THE INVENTION

The lens-implement according to the present invention has the body of the implement formed by two opposing main rectangular surfaces and a planiform space enclosed by the two main surfaces provided with a plurality of optical elements along the direction of the length of the main rectangular, and includes a metal frame forming at least one main surface of the above-mentioned main surfaces, and a mold unit incorporated into the metal frame.

The lens-implement further includes: a reflective optical element for directing the optical axis of incident light by reflecting the incident light; a movable lens frame arranged on the second optical axis which is the directed optical axis, and arranged as movable along the second optical axis; and a drive unit for driving the movable lens frame. The drive unit includes a cam member as an axis with a cam portion for positioning the movable lens frame formed on the circumference; and a motor for rotating the cam member. The cam member is configured with the central axis arranged parallel to the second optical axis near the reflective optical element.

The lens-implement includes a lens frame provided as freely movable in the optical axis direction; a self-moving unit for freely moving parallel to the optical axis; and coupling unit having a movement transmission member one end of which is fixed to the self-moving unit while the other end of which touches the lens frame and a propelling member for propelling the movement transmission member to the touch portion of the lens frame with a view to coupling the self-moving unit with the lens frame.

The encoder according to the present invention includes: a magnetic sensor attached to a stationary member; a magnetic scale arranged with one portion fixed to a movable member such that relative travel can be attained with respect to the magnetic sensor with the scale face directed toward the magnetic sensor; and a pressure unit attached to the stationary member for pressing the portion not fixed to the movable member of the magnetic scale against the magnetic sensor from the opposite side of the scale surface so that the scale surface of the magnetic scale can slide against the detection unit of the magnetic sensor.

Furthermore, the digital camera is configured by loading a lens-implement with the above-mentioned encoder attached thereto.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The embodiments of the present invention are explained below by referring to the attached drawings. In the following explanation, the above-mentioned one main surface is formed by, for example, the surface of a metal frame23aand the surface of a first fixed lens frame unit15, etc. incorporated into the metal frame23a. The other opposing main surface is an open surface. The optical element is formed by, for example, a prism L1, lenses L2through L9, etc. The reflective optical element is formed by the prism L1, etc. The mold unit is formed by, for example, the first fixed lens frame unit15, a second fixed lens frame unit16, etc. One side is formed by, for example, a metal frame23b, and the other side is an open surface. A first guide member is formed by, for example, a first guide shaft65, etc., and a second guide member is formed by a second guide shaft68, etc. A first guide member support unit is formed by, for example, guide shaft support holes64(64-1,64-2), etc. and a second guide member support unit is formed by guide shaft support holes67, etc.

FIGS. 1A and 1Broughly show the configuration of the digital camera according to an embodiment of the present invention.FIG. 1Ais a perspective view of the appearance of the digital camera viewed from the front.FIG. 1Bis a perspective view showing the arrangement of the important portion inside the digital camera.

As shown inFIG. 1A, a digital camera1has a taking lens window2at the upper right corner of the front surface, and a strobe light emission window3to the left of the taking lens window2. A release button4is mounted on the left end of the top surface.

As shown inFIG. 1B, a control device comprising a circuit substrate5loaded with various electronic parts, a removable battery6, etc. are arranged in the space inside the digital camera1occupying an approximately ⅔ portion on the left inside the digital camera1. Then, a unit of a lens-implement7is arranged in the approximately ⅓ portion on the right inside the digital camera1.

The lens-implement7reflects the ray flux from the subject along a taking optical axis O1shown inFIG. 1Bthrough the taking lens window2shown inFIG. 1Aand directs it about 90° downward, and the input ray flux is led to the image pickup device comprising, for example, a CCD, etc. provided at the lower end portion of the lens-implement7along a second optical axis O2directed downward as described later, thereby generating a captured image.

FIG. 2shows the digital camera1viewed from the left side shown inFIG. 1Balong the line A-A′ through the lens-implement7shown inFIG. 1B, and shows the rough configuration of each portion of the lens unit.

As shown inFIG. 2, the lens-implement7comprises in the inside a plurality of lenses including a first fixed lens unit8comprising the prism L1and the lens L2along the second optical axis02directed downward, a first movable lens unit9comprising the lens L3and the lens L4, a second movable lens unit11comprising the lens L5, the lens L6, and the lens L7, a third movable lens unit12comprising the lens L8, and the second fixed lens unit13comprising the lens L9. An image pickup device14is provided at the end of the above-listed lenses.

The prism L1of the first fixed lens unit8reflects and directs about 90° downwards the ray flux from the subject input along the taking optical axis O1through the above-mentioned taking lens window2, and the prism which changes the direction of the ray flux along the second optical axis O2is laminated with a normal lens into an incorporated unit. The resultant unit is held with the lens L2in the first fixed lens frame unit15and fixed in the lens-implement7. The lens can be incorporated with the prism without lamination. The second fixed lens unit13is held in the second fixed lens frame unit16, and fixed in the lens-implement7.

The first fixed lens frame unit15and the second fixed lens frame unit16are formed as resin molds as incorporated at the end in the direction of the length of the metal frame which is described later and has an L-character shaped section normal to the second optical axis02.

A first movable lens frame17holding the first movable lens unit9, a second movable lens frame18holding the second movable lens unit11, and a third movable lens frame19holding the third movable lens unit12are mounted between the first fixed lens frame unit15and the second fixed lens frame unit16.

The first movable lens frame17, the second movable lens frame18, and the third movable lens frame19respectively hold the first movable lens unit9, the second movable lens unit11, and the third movable lens unit12in a way such that they can be independently movable along the second optical axis O2directed substantially normal to the prism L1.

The first movable lens unit9and the second movable lens unit11are mounted to change the focal distance of the ray flux of the subject input along the second optical axis O2of the optical system of the lens-implement7. That is, the first movable lens frame17and the second movable lens frame18respectively holding the first movable lens unit9and the second movable lens unit11are mounted to adjust the zoom ratio of the lens system.

The third movable lens unit12is mounted to adjust the focusing position in which the above-mentioned ray flux forms an image on the image pickup device14. That is, the third movable lens frame19for holding the third movable lens unit12is mounted as a lens frame for focusing as freely movable in the direction of the second optical axis O2.

A diaphragm position (which can be a shutter position)21is set between the first movable lens unit9and the second movable lens unit11.

The lens unit is configured such that the thickness (depth) of the unit can be the smallest possible, and a part or all of the front or back along the second optical axis O2(the backward portion of the digital camera1in the example shown inFIG. 2) of the frame structures of the first fixed lens frame unit15, the second movable lens frame18, and the third movable lens frame19respectively supporting the first fixed lens unit8, second movable lens unit11, and the third movable lens unit12respectively including the lenses L2, L5, and L8having relatively large diameters are cut out to form the cut out portions15-1,18-1, and19-1.

For the second and the third movable lens frames18and19, the strengths of which become weak by the amount of the cut frame walls, and which do not have another reinforced portion unlike the first fixed lens frame15, a convex part which protrudes externally and will be described later, is provided on a side opposite to the cut parts with reference to the second optical axis O2, namely, on the frame walls on the top surface. The reason why the frame walls of the second and the third movable lens frames18and19on the top surface look slightly thick inFIG. 1Bis that the cross sections of the convex parts are depicted.

Additionally, since the whole of the third movable lens frame19is thin and weak in the direction of a width, it can be possibly insufficient to make reinforcement only with the above described convex parts. Therefore, a protruding part19-2is provided to wrap from a lens barrel part formed on a side opposite to the cut part19-1formed at the bottom of the lens L8toward the left hand side, which is out of range of the effective light beam of the lens L8.

FIG. 3is a exploded perspective view of the lens-implement7viewed from the front of the digital camera1.

FIG. 4is a exploded perspective view of the lens-implement7viewed from the back of the digital camera1.

InFIGS. 3 and 4, the components also shown inFIGS. 1 and 2are assigned the same reference numerals assigned inFIGS. 1 and 2.

As shown inFIGS. 3 and 4, the lens-implement7comprises a main fixed lens frame22. When all components shown inFIG. 3or4are mounted and stored inside and outside the main fixed lens frame22, the entire components form the outline of the body of the implement formed by two opposing rectangular main surfaces and the rectangular parallelepiped space enclosed by the two main surfaces.

The main fixed lens frame22forms at least one main surface of the above-mentioned two main surfaces. With the configuration of the lens-implement7, the other main surface is open. On side of the rectangular parallelepiped space enclosed by the main surface formed by the metal frame23aand the other open main surface is also formed by the metal frame23bmounted substantially normal to the metal frame23a.

The side in the direction normal to the length (upper side direction normal to the length inFIGS. 3 and 4) is formed by a metal frame23cmounted substantially normal to the metal frame23aof the main surface and the metal frame23bon the side in the direction of the length.

Thus, a metal frame23(23a,23b) forms an L-shaped frame by a section normal to the direction of the length (also the direction of the second directed optical axis O2) as one main surface and a side in the direction of the length to produce a frame of an ideal structure having sufficient rigidity using a small amount of material.

At one end portion in the direction of the length of the metal frame23, a fixed mold unit is incorporated into the metal frame23in an outsert molding. These two fixed mold units are the first fixed lens frame unit15and the second fixed lens frame unit16shown inFIG. 2.

The first fixed lens frame unit15includes the prism L1shown inFIG. 2and the lens L2omitted inFIGS. 3 and 4in a fixed state. The second fixed lens frame unit16fixedly holds the lens L9shown inFIG. 2but omitted inFIGS. 3 and 4.

Between the first fixed lens frame unit15and the second fixed lens frame unit16, the three movable lens frames also shownFIG. 2(the first movable lens frame17, the second movable lens frame18, and the third movable lens frame19) are arranged.

These three movable lens frames and the above-mentioned two fixed lens frames are provided with an adhesive catch unit24(refer toFIG. 3) for holding and fixing each lens. The adhesive catch unit24is a small space portion formed between the circumferential side of a fixed lens and the lens frame.

The adhesive catch units of the third movable lens frame19and the second fixed lens frame unit16cannot be seen inFIG. 3because they are hidden. The adhesive catch unit of the first fixed lens frame unit15is described later.

Before the above-mentioned three movable lens frames are incorporated, a zoom shaft cam25is arranged close to side portion in the direction of the length on the open side of the main fixed lens frame22and the side of the first fixed lens frame unit15. The zoom shaft cam25has a large diameter part having the bottom of the cam groove of the cam member and forming the circumferential side, and a small diameter part26(26a,26b) coaxially projected from both ends of the large diameter part. A gear27is fixed to the small diameter part26aprojected to the end portion opposite the image pickup device14.

The zoom shaft cam25passes the small diameter part26athrough a bearing engagement hole28formed in the incorporated and fused portion with the metal frame23cof the first fixed lens frame unit15, pulls it downwards with the small diameter part26bengaged into the bearing hole formed in the first fixed lens frame unit15not seen inFIG. 3because it is hidden, and allows the small diameter part26ato be engaged with a shaft bearing29in the bearing engagement hole28. Thus, the zoom shaft cam25can be supported as rotating for the first fixed lens frame unit15.

A small convex portion31having a further smaller diameter is formed at the projection of the small diameter part26aof the zoom shaft cam25. The convex portion31projects upward and outside from the shaft bearing29when the small diameter part26ais engaged with the shaft bearing29. By pressing the convex portion31with the propelling force of a propelling leaf spring32, the zoom shaft cam25is positioned by the upper and lower bearings, and held stably.

The propelling leaf spring32is configured by three curved leg portions32-1separated from the substantially rectangular body downward along the cutting line, and then horizontally bent at each tip portion, a holder piece32-2formed by cutting out the central portion of the body, and a propelling spring unit32-3extended from the body and having a convex portion projecting toward the pickup device near the tip.

On the other hand, on the metal frame23c, three cutout portions33are formed in the positions corresponding to the three curved leg portions32-1of the propelling leaf spring32, and a convex portion34corresponding to the holder piece32-2of the propelling leaf spring32is formed substantially at the center surrounded by the three cutout portions33.

When the body of the propelling leaf spring32is pushed into the metal frame23cwith the thee curved leg portions32-1of the propelling leaf spring32engaged with the three cutout portions33of the metal frame23c, the tip of the holder piece32-2is engaged in the circumferential side of the convex portion34, the propelling leaf spring32is positioned outside the metal frame23c, the convex portion31of the zoom shaft cam25is pressed with propelling force by the convex portion at the tip of the propelling spring unit32-3, thereby performing the positioning.

Thus, the zoom shaft cam25is arranged near the prism L1held by the first fixed lens frame unit15with the central axis arranged in the direction of the length of the main fixed lens frame22, that is, parallel to the second optical axis O2, and is arranged with at least a part in the axis direction placed adjacent to the side of the prism L1.

Then, a zoom motor unit35is arranged in the space of the substantially triangular pillar formed by the slope of the first fixed lens frame unit15holding the reverse side of the reflective face of the prism L1and the metal frame23c, and a reduction gear train36is engaged with the gear27of the zoom shaft cam25. The zoom motor unit35is fixed to the first fixed lens frame unit15by the two holders (refer toFIG. 4) of a gear shaft fixing part37and a holding plate fixing part38screwed on a positioning hole39and a holding hole41formed in the first fixed lens frame unit15. The engagement between the reduction gear train36and the gear27of the zoom shaft cam25is described later in detail.

After the process above, an aperture/shutter unit42is assembled to the main fixed lens frame22. The aperture/shutter unit42(seeFIG. 2) comprises an aperture/shutter part43having an aperture which controls the amount of passing light of reflection light forming the second optical axis O2, and a shutter, and rotary solenoids44and45which respectively drive the aperture and the shutter of the aperture/shutter part43in a mechanical manner.

The aperture/shutter part43is arranged in the diaphragm position (shutter position)21shown inFIG. 2, and the two rotary solenoids44and45are arranged below the zoom shaft cam25. The aperture/shutter unit42is described later in detail.

Furthermore, an ultrasonic linear motor46and a magnetic sensor unit47for movably driving the third movable lens frame19are arranged below the aperture/shutter unit42as overlapping each other in the short side direction of the main fixed lens frame22.

Thus, the ultrasonic linear motor46is arranged on the taking side (in front of the body, that is, the side from whichFIG. 1Bis obtained) in the position in a direct extension of the axis of the zoom shaft cam25.

The magnetic sensor unit47(refer toFIG. 4) comprises a magnetic sensor holder48, a magnetic sensor49, a magnetic scale51, and a propelling spring52.

The above-mentioned ultrasonic linear motor46and the magnetic sensor unit47are described later in detail.

Thus, after each of the above-mentioned members is arranged, the first movable lens frame17, the second movable lens frame18, and the third movable lens frame19to which the movable lens units (9,11, and12, but omitted inFIGS. 3 and 4) shown inFIG. 2are fixed using an adhesive agent are mounted.

Then, for the circumferences of the lens holders of the first, second, and third movable lens frames17,18, and19, the surface before and after (relative to the lens-implement7shown inFIG. 1B) the digital camera1about the second optical axis O2is formed flat, thereby realizing a slim movable lens frame incorporated into the lens-implement7.

Furthermore, for a further reduction in the thickness of the frame structures at the rear portion (the upper left portion shown inFIG. 3, the lower right portion shown inFIG. 4) of the lens frame holding a lens of the lens the second and third movable lens frames18and19corresponding to the flat circumferential side portion at the rear of the lens are cut out to form the cutout portion18-1,19-1(refer toFIGS. 2,3, and4), and a flat circumferential side portion of the rear of the lens is exposed.

The first movable lens frame17, the second movable lens frame18, and the third movable lens frame19(refer toFIG. 4) are respectively provided with a bearings53(53-1,53-2, and53-3), and the bearings53are provided with guide holes54(54-1,54-2, and54-3).

Additionally, the first movable lens frame17, the second movable lens frame18, and the third movable lens frame19are provided with U-shaped cutout portions55(55-1,55-2, and55-3) at the tip opposite the above-mentioned bearing53.

Furthermore, a light reflective member59is attached and arranged at a step portion58formed in boundary between a front end outer surface56opposite the rear end portion having the bearing53of the first movable lens frame17and the U-shaped cutout portion55(refer toFIG. 3) and a side portion57on which the bearing53is arranged.

Furthermore, cam followers61(61-1,61-2) are respectively formed at the portion provided as incorporated into the bearing53-1of the first movable lens frame17and in a portion which is provided to extend integrally with the bearing53-2of the second movable lens frame18.

In addition, a light reflective member62is attached to the side horizontally extending on the bearing53-3of the third movable lens frame19.

Convex portions63(63-2,63-3) for reinforcement as explained by referring toFIG. 2are formed in the second movable lens frame18and the third movable lens frame19on the front end outer surface opposite the rear end portion having the bearing53and the U-shaped cutout portion55.

The convex portion63is provided to reinforce the strength of the lens frame from which the frame structure is cut out to make a slim implement as described above.

A first guide shaft65both ends of which are supported by guide shaft support holes64(64-1,64-2) formed at the corner closest to the side of the aperture and the main surface of the aperture of the first fixed lens frame unit15and the second fixed lens frame unit16respectively is inserted into guide holes54of the three movable lens frames.

Thus, the first, second, and third movable lens frames17,18, and19(that is, the three movable lens units9,11, and12) are supported as movable in the direction of the optical axis O2.

Since the guide shaft support hole64(64-1,64-2) supporting the first guide shaft65are formed at the corner closest to the side and the main surface of the aperture, the first guide shaft65is arranged at the closest possible outermost portion where the open side and the open main surface cross, inner main body of the lens implement7formed by main fixed lens frame22. Thus, by the first guide shaft65arranged in the closest possible outermost position supporting the bearing53, the three movable lens frames can be arranged in the narrow rectangular parallelepiped space in the body of the implement without waste.

When the first guide shaft65is inserted, a compression spring66having propelling force is externally engaged in the first guide shaft65, and intervenes between the bearing53-1of the first movable lens frame17and the bearing53-2of the second movable lens frame18.

Before the assembly of the above-mentioned three movable lens frames, the second guide shaft68, both ends of which are supported by the other two guide shafts support holes67(refer toFIG. 4) formed in the position closest to the closed side and the main surface of the aperture configured in the metal frame23bof the first fixed lens frame unit15and the second fixed lens frame unit16, is arranged.

The second guide shaft68is positioned on the emission side of the prism L1held in the first fixed lens frame unit15. In detail, as shown inFIG. 5(b), it is arranged in the above-mentioned position by the guide shaft support hole67formed in the projection range in the emission side direction of the prism L1, out of the effective optical range of the ray flux on the emission side, and near the effective optical range.

In the assembly of the above-mentioned three movable lens frames, after the U-shaped cutout portions55(55-1,55-2, and55-3) are supported as engaged in the second guide shaft68from the side and as freely sliding on it, each movable lens frame is rotated inward along on the second guide shaft68, and the cam follower61arranged in the first movable lens frame17and the second movable lens frame18is caught in the cam groove of the zoom shaft cam25as freely sliding and making intrusion.

That is, the cams (the cam grooves with which the cam followers61-1and61-2are engaged) corresponding to a plurality of lens frames (the first movable lens frame17and the second movable lens frame18in this example) are formed in the zoom shaft cam25.

Simultaneously, the front end outer surface56(refer toFIG. 3) of the first movable lens frame17, which forms one main surface of the metal frame23a, is arranged on the reverse of the metal frame23a, and the reinforcing convex portions63formed on the front end outer surfaces of the second movable lens frame18and the third movable lens frame19are engaged in an aperture69formed in the metal frame23a.

The aperture69is formed as a above and below long aperture depending on the travel stroke of the movable lens to avoid the interference with the movable lens (refer to the lenses L5through L8shown inFIG. 2) which travels as the second movable lens frame18and the third movable lens frame19, that is, to avoid the interference with the travel of the convex portion63.

Then, the first guide shaft65is inserted into the guide hole54of the bearing53of each movable lens frame and the guide shaft support hole64at both end portions. Thus, the two guide shafts (65and68) are adjacent to the zoom shaft cam25, and is arranged parallel to the axis of the zoom shaft cam25.

Thus, since the axial members are arranged adjacent and parallel to each other, the implement can be downsized.

By the support of these two guide shafts, the three movable lens frames (17,18, and19) are set as sliding vertically (in the direction of the optical axis O2), one guide shaft stops the rotation around the other guide shaft, the position normal to the optical axis O2is set in the main fixed lens frame22.

By the compression spring66externally engaged and intervening the first guide shaft65between the bearing53-1of the first movable lens frame17and the bearing53-2of the second movable lens frame18, the first movable lens frame17and the second movable lens frame18are propelled toward the opposite directions.

Thus, the cam followers61-1and61-2engaged with the cam groove of the zoom shaft cam25are pushed toward the opposite sides of the groove structure of the cam groove. Therefore, the idle generated between the cam groove and the cam follower when the zoom shaft cam25is driven for rotation can be removed. Thus, the displacement between the upward travel and the downward travel can be correctly controlled.

In the above-mentioned arrangement, the first guide shaft65is arranged adjacent parallel to the zoom shaft cam25.

Then, the image pickup device14also shown inFIG. 2is attached below the bottom of the second fixed lens frame unit16. A photosensor attachment hole71is provided in the position corresponding to the light reflective member59attached to the first movable lens frame17on the first fixed lens frame unit15located on the same plane as the metal frame23a, and a photosensor72is arranged into the photosensor attachment hole71.

The photosensor72detects the initial position of the first movable lens frame. The transfer distance of the first movable lens frame from the detected initial position can be determined by detecting the transfer position by the control device (not shown in the attached drawings) counting the number of steps of the zoom motor driven by the zoom motor unit35.

Another photosensor73is arranged in the position corresponding to the light reflective member62attached to the third movable lens frame19on the side opposite the open side of the second fixed lens frame unit16. The photosensor73detects the initial position of the third movable lens frame19by detecting the reflected light from the light reflective member62attached to the third movable lens frame19.

FIG. 5Ais an enlarged perspective view of the construction of the first fixed lens frame unit15holding the first fixed lens unit8shown inFIG. 12from a different direction.FIG. 5Bshows the view from the direction of the lens L2(in the direction of the optical axis O2). The above-mentioned configuration includes the reference numerals assigned to the components commonly shown inFIGS. 1 through 4.

As shown inFIG. 5A, the first fixed lens frame unit15is provided with the bearing engagement hole28into which the small diameter part26aof the zoom shaft cam25is inserted, and a bearing hole74which supports the other small diameter part26bof the zoom shaft cam25but is hidden and cannot be seen inFIG. 3.

FIGS. 5A and 5Bshow the first fixed lens frame unit15incorporated into the metal frame, but the metal frame is omitted in the figures. The portions of the metal frames23aand23bshown inFIGS. 3 and 4are located on the top surface and the right side inFIG. 5B.

To the first fixed lens frame unit15, the first fixed lens unit8, the zoom shaft cam25for transferring the first and second movable lens frames17and18with predetermined physical relationship along the second optical axis O2directed by the prism L1, the zoom motor unit35for rotating the zoom shaft cam25on the rotation axis, etc. are attached.

First, in the first fixed lens unit8shown inFIG. 2held by the first fixed lens frame unit15, the prism L1is located in the place not interfering with the effective optical range of the reflective face of the prism by a convex part75formed on left and right parts inside the first fixed lens frame15, as described later in detail as shown inFIG. 6A, and fixed by an adhesive filled in the space formed by the adhesive catch unit24in the portion not interfering with the effective optical range of a emission side of prism to the first fixed lens frame unit15.

The other lens L2contained in the first fixed lens unit8forms a smooth circumferential side76with the upper and lower circumferential sides cut out along the directed optical axis O2to make a slim lens-implement7. As a result, the lens L2forms an ellipse77In addition to the form of the ellipse77, in the portion holding the lens L2of the first fixed lens frame unit15, the portion corresponding to at least one (lower portion in the drawing) of the smooth circumferential sides76of the cutout portions of the lens L2formed in the ellipse77forms a cutout portion78on the plane parallel to the optical axis O2. Therefore, the lens-implement7can be further slim.

The circumferential portion excluding the smooth circumferential side76of the lens L2contained in the first fixed lens unit8is held by four convex portions79(79-1,79-2,79-3, and79-4) provided in the first fixed lens frame unit15.

As shown inFIG. 5B(refer toFIG. 5A), the guide shaft support hole67provided in the first fixed lens frame unit15to hold the second guide shaft68is formed in the place closest to the closed side and the open main surface (lower side inFIGS. 5A and 5B) configured by the metal frame23btogether with the other guide shaft support hole67not shown inFIG. 5Bas described above.

Thus, as shown inFIG. 5A, the guide shaft support hole67is positioned at the emission side (also the lens L2side) of the prism L1held by the first fixed lens frame unit15, and is formed as shown inFIG. 5Bin the projection range L1′ in the emission side direction of the outline of the prism L1, out of the effective optical range of the emission side ray flux (same range as the front side of the elliptical lens L2), and near the effective optical range.

Therefore, the second guide shaft68supported by the two opposite guide shaft support holes67are arranged in the similar positions as described above.

The guide shaft support hole64-1provided in the first fixed lens frame unit15to support the first guide shaft65shown inFIGS. 3 and 4is, as above mentioned, provided at the corner closest to the aperture side opposite the metal frame23band the aperture main surface opposite the metal frame23atogether with the other guide shaft support hole64-2provided in the second fixed lens frame unit16not shown inFIG. 5B.

Therefore, the first guide shaft65supported by the two opposite guide shaft support holes64-1and64-2is arranged in the similar position as described above.

As a result, in other words, the cross section (23aand23b) configuring an L-shaped form of the metal frame23forming part of the main fixed lens frame22is, as shown inFIG. 5B, provided on the opposite side of the first guide shaft65over the plane k or p containing the optical axis O2directed by the prism L1.

FIG. 6Ais an exploded perspective view of the material incorporated into the first fixed lens frame unit15.FIG. 6Bis a side view of the zoom motor unit35incorporated into the first fixed lens frame unit.

FIG. 6Ashows the configuration in the first fixed lens frame unit15such as the adhesive catch unit24, the convex portion75and etc. for the prism L1, which are composition inside the opposite side not shown shadily by the prism L1inFIG. 5. Furthermore, by removing the lens L2, the adhesive catch unit24, the four convex portions79and the cutout portion78for the lens L2. Although they are not shown exactly inFIG. 5.

FIG. 6Bshows a side view of the zoom motor unit35and a side sectional view of the first fixed lens frame unit15.

As shown inFIG. 6A, the first fixed lens frame unit15has a slope portion81along a reflective surface of the prism L1, and the slope portion81is provided with a small rectangular convex portion82in the position out of the effective optical range of the reflective surface of the prism L1corresponding to the lower end portion of the convex portion75for the prism L1.

To store the zoom motor unit35shown inFIG. 6Bin the space at the back of the slope portion81, and a gap as originally idle space at the back of the prism without waste, three cutout groove holes83are formed as cut out for free space of the upper corner of the zoom motor unit35.

To avoid the entry of harmful light from the back through the cutout groove hole83to the reflective surface of the prism L1, there is a visor84between the surface of the slope portion81and the reflective surface (reverse side) of the prism L1. On both ends of the visor84, a cutout portion85for engagement with the convex portion82is formed. The cutout portion85forms free space for the convex portion82, and has the function of positioning the visor84.

A motor86of the zoom motor unit35is configured by a stepping motor. As shown inFIG. 6B, the motor86is close to the slope portion81, and arranged opposite the prism L1(free space at the back) about the slope portion81. An output axis87is arranged parallel to the second optical axis O2.

FIG. 7shows the configuration of the zoom motor unit35, and the engagement between the zoom motor unit35and the zoom shaft cam25.FIG. 7shows the objects shown inFIG. 6as shown from the other side below. That is, it is a perspective view of the zoom motor unit35and the zoom shaft cam25taken out and set upside down.

As shown inFIG. 7, the zoom motor unit35is attached with a base plate88mounted on the side for which the output axis87of the motor86is provided. A plurality of gears are mounted on both surfaces and form the gear train36for transmitting the rotation of the motor86to the zoom shaft cam25.

The gear train36comprises a drive gear89attached to the output axis87of the motor86, an idle gear91directly engaged with the drive gear89, a large diameter gear92of the first reduction gear for engagement with the idle gear91, a small diameter gear93configuring the first reduction gear with the large diameter gear92, a large diameter gear94of the second reduction gear for engagement with the small diameter gear93, and a small diameter gear95composing the second reduction gear with the large diameter gear94, for direct engagement with the gear27of the zoom shaft cam25.

The zoom motor unit35is fixed with the rotation axis of the second reduction gear having the small diameter gear95for engagement with the gear27of the zoom shaft cam25incorporated into the positioning hole provided in the first fixed lens frame unit15and screwed to the first fixed lens frame unit15through an attachment hole88-2of an attachment unit88-1set after directed approximately normal to the base plate88.

In the zoom motor unit35, the drive gear89of the output axis87, the idle gear91, and the large diameter gear92of the first reduction gear are arranged on the same plane of the base plate88, and the small diameter gear93of the first reduction gear and the large diameter gear94and the small diameter gear95of the second reduction gear are arranged on the opposite surface of the idle gear91of the base plate88.

That is, the gear (small diameter gear95of the second reduction gear) directly engaged with (the gear27of) the zoom shaft cam25in the gear train36comprising a plurality of gears incorporated into the base plate88is engaged with the base plate opposite the base plate of the gear (idle gear91) directly engaged with the gear (drive gear89) of the output axis87in the gear train36.

Thus, a plurality of reduction gears are arranged on both sides of the base plate88on which the drive gear89of the output axis87parallel to the second optical axis O2is arranged, and at least one set of reduction gears is attached over both sides of the base plate88, and the small diameter gear95of the second reduction gear, which is the gear at the final stage of the gear train36on the opposite side of the base plate88relating to the drive gear89, rotates the zoom shaft cam25by the engagement of the gear27provided on the zoom shaft cam25arranged parallel to the second optical axis O2, thereby configuring the gear train36for transmission of the drive force to the zoom shaft cam25with all spur gears, and shortening the engagement between the zoom motor unit35and the zoom shaft cam25by at least one gear in the axis direction.

Thus, the configuration of the zoom motor unit35can be simplified, and the engagement between them can be realized in the smallest possible space.

By right and reverse turns of the motor86in the zoom motor unit35, the zoom shaft cam25is rotated to difference direction at a predetermined angle.

By the engagement of the cam follower61-1of the first movable lens frame17and the cam follower61-2of the second movable lens frame18(refer to.FIG. 3) with the first cam groove25-1and the second cam groove25-2formed to the outer circumference of the zoom shaft cam25, the first movable lens frame17and the second movable lens frame18(that is, the first movable lens unit9and the second movable lens unit11) travels with alternate attachment/detachment in the direction of the second optical axis O2depending on the rotation of the zoom shaft cam25, thereby performing a reducing/enlarging zoom on a subject image.

FIG. 8is a partial exploded and perspective view of the aperture/shutter unit42.FIG. 8shows the aperture/shutter unit42shown inFIG. 3viewed from substantially right above. As shown inFIG. 8, the contour of each of the rotary solenoids44and45of the aperture/shutter unit42is substantially square, with one surface (lower surface inFIG. 8) fixed to the base plate96, and is fixed to the metal frame23athrough the base plate96.

The rotary solenoid44is a drive unit for a diaphragm, provided with a long arm97extended from a clearance44-1on the side along the side of the other rotary solenoid45, and the long arm97is rotated by a predetermined range of angle.

At the tip of the long arm97, an engagement portion97-1with the diaphragm mechanism of the aperture/shutter part43is provided in an extended condition as a pin. A groove is made at the root of the long arm97from the clearance44-1, and one end of a two-legged spring98is engaged with the groove, the other end of the two-legged spring98is engaged with a spring holder hole96-1made in the base plate96.

The propelling force of the two-legged spring98propels the long arm97constantly upwards as shown inFIG. 8, that is, counterclockwise as viewed in the direction of the arrow a. The upper position of the long arm97as shown inFIG. 8is the position in which the optical filter (not shown inFIG. 8) in the engaged diaphragm mechanism is saved from the optical path.

The other rotary solenoid45is a drive unit for a shutter, and is provided with a short arm99mounted as extended outside from a clearance45-1of a side of the rotary solenoid45parallel to the long arm97. The short arm99is rotated by a predetermined range of angle.

A engagement portion99-1is also provided as a pin and engaged with the shutter open/close mechanism of the aperture/shutter part43.FIG. 8shows the state in which the short arm99stops after rotating downwards, that is, clockwise as viewed in the direction of the arrow a. This is the position in which the shutter of the shutter open/close mechanism engaged with the arm is saved from the optical path.

Then, the aperture/shutter part43is attached to the base plate96. Thus, the drive unit of the diaphragm mechanism of the aperture/shutter part43is engaged with the engagement portion97-1of the long arm97, and the drive unit of the shutter open/close mechanism of the aperture/shutter part43is engaged with the engagement portion99-1of the short arm99.

When the aperture/shutter unit42is incorporated into the metal frame23athrough the base plate96, the aperture/shutter part43is arranged in the diaphragm position21shown inFIG. 2between the first and second movable lens units9and11.

The aperture/shutter unit42is not shown in the attached drawings, but comprises a shutter for opening and closing the path of the ray flux traveling through the optical axis O2, the optical filter (ND filter) for controlling the amount of light on the image capturing surface, and the filter open/close mechanism for moving the optical filter forward and backward in the path of the ray flux.

When a voltage is applied to the rotary solenoid44through the control device of the circuit substrate5, the long arm97rotates downward against the propelling force of the two-legged spring98. In cooperation with this, the filter mechanism of the aperture/shutter part43allows the optical filter to enter the path of the ray flux, and when the application of the voltage is stopped, the propelling force of the two-legged spring98rotates the long arm97upward as shown in the figure. In cooperation with this, the filter mechanism allows the optical filter to exit the path of the ray flux.

When the voltage is applied to the rotary solenoid45in the closing direction of the shutter through the control device of circuit board5, the short arm99rotates upward. When the application of the voltage is stopped, the status is held. Thus, the shutter open/close mechanism of the aperture/shutter part43in cooperation with the short arm99closes the shutter and cut off the path of the ray flux, and the status is maintained.

On the other hand, when the voltage is applied to the rotary solenoid45in the shutter opening direction through the control device of the circuit substrate5, the short arm99is rotated downward as shown Figure. When the application of the voltage is stopped, the status is held. Thus, the shutter open/close mechanism of the aperture/shutter part43in cooperation with the short arm99opens the shutter, releases the path of the ray flux, and the status is maintained.

Described below is the ultrasonic linear motor for driving the travel of the third movable lens frame holding the third movable lens unit12for focusing.

FIG. 9Ais a exploded perspective view of the ultrasonic linear motor for use in the present example.FIG. 9Bis a perspective view showing the completion of the assembly. As shown inFIGS. 9A and 9B, an ultrasonic linear motor100comprises a rectangular vibrator (ultrasonic vibrator)101, and a plurality of (two in the example shown in the figure) projection-shaped self-moving contact parts102(102-1,102-2) adhered on the two upper and lower opposite surfaces of the vibrator101as incorporated into the vibrator101as one unit or separately adhered.

Furthermore, the ultrasonic linear motor100comprises two guide shafts103(103-1,103-2) for guiding the movement of the vibrator101opposite on the positions upper and lower the vibrator101through the self-moving contact part102, and a support portion104which sustains above whole parts positioning them.

On the support portion104, setting portions104-2are mounted on both ends of the base portion104-1as incorporated therein. Above the setting portions104-2, the fixed shaft bearing holes105adhered to and for support of the upper guide shaft103-1in the two guide shafts103are formed. Below the structure, shaft bearing long holes106are formed for support of the lower guide shaft103-2as allowing oscillation.

Outside the base portion in the vicinity of both ends of the base portion104-1, convex portions107are provided in the positions corresponding to the lower guide shaft103-2inserted into the shaft bearing long holes106. The convex portions107are hollow as viewed from above, which is not clearly shown in the attached drawings though. A coil spring108is held inside the hollow portion.

At the outer bottom portion near both ends the base portion104-1of the support portion104, a convex portion107at corresponding location to a lower guide shaft103-2inserted into the shaft bearing long hole106is respectively provided, and the convex portion107is not clearly seen in the figure, but it is hollow when viewed from above, and a coil spring108is held in the hollow portion.

Then, the upper end portion of the coil spring108projecting exterior upwards from inner hollow portion propels the lower guide shaft103-2upwards in the vicinity of both end portions of the lower guide shaft103-2. Thus, the lower guide shaft103-2is held by the shaft bearing long hole106as vertically moving by the vibrating movement, which is described after, of the vibrator101held tight by the upper guide shaft103-1and the lower guide shaft103-2and the propelling force of the coil spring108.

To prevent the loss or omission of the freely moving lower guide shaft103-2from the long bearing hole106, a antiskid pin109is arranged as touching both end portions of the lower guide shaft103-2inserted to the shaft bearing long hole106, and the antiskid pin109is adhered into a pin fixing groove111formed on the outside of the aperture of the shaft bearing long hole106.

The vibrator101moves forward and backward between the setting portion104-2on both ends in the direction parallel to the guide shafts103-1and103-2indicated by the arrow b in both directions as shown inFIG. 9Bby the specific vibration movement described later and the effect of the self-moving contact part102the two guide shafts103-1and103-2.

The above-mentioned self-moving contact part102has a cutout portion having a curved surface at the curvature substantially the same as the radius of the first and second guide shaft103at the contact surface of the first and second guide shaft103. Thus, the self-moving contact part102is regulated to freely move in the direction along the first and second guide shaft103.

The ultrasonic linear motor100according to the present embodiment shown inFIG. 9Bis configured such that the vibrator101itself can be freely moved. The configuration of the vibrator101is briefly explained below.

FIG. 10shows the wiring of an electrode to the vibrator101not shown inFIGS. 9A and 9B. InFIG. 10, the direction of the vibrator101is opposite to that shown inFIGS. 9A and 9B.

The inside of the vibrator101shown inFIG. 10is not specifically shown, but two piezoelectric multilayer units112(112A,112B) like square pillar are arranged side by side, thus forming the parallelepiped vibrator101.

The configuration of the piezoelectric multilayer unit112is not shown in detail, but it is multilayer unit layered with a plurality of a thin rectangular piezoelectric sheet, made of, for example, PZT (titanium zirconate lead) etc. treated by electrode processing, and is layered with two non-electrode processed insulator layers on top and end as is held tight.

The outermost insulator layers formed in the direction of the piezoelectric layers form opposed faces of the vibrator101held tight by the two guide shafts103through the self-moving contact parts102as shown inFIG. 9, namely, upper and lower faces101-1and101-2of the vibrator101as shown inFIG. 10.

The other side of the piezoelectric multilayer unit112, that is, the face parallel to the two guide shafts103shown inFIG. 9Bof the vibrator101not facing the guide shaft103, and the face normal to the direction of the two guide shafts103are also covered with appropriate insulator layers.

Then, the vibrator101is provided with four external electrode terminals A+, A-, B+, B− for the one side101-3in the two sides not facing but parallel to the two guide shafts103as shown inFIG. 10. These external electrode terminal A+, A−, B+, B− are connected to the inner electrode of each piezoelectric layer on which the inner electrode process is performed. The electrode terminals A+ and A− are configured as A-phase electrodes, and the electrode terminals B+ and B− are configured as B-phase electrodes.

The ultrasonic elliptic vibration described later is generated in the vibrator101by the drive voltage applied from the control device to the external electrode terminals A+, A−, B+, and B−.

The self-moving contact part102formed as projections on the layer directional faces of the piezoelectric multilayer unit112, that is, prospectively on two portions in the two faces of the face101-1and the face101-2formed by the above-mentioned insulator layers of the vibrator101, is prospectively provided in an arbitrary position in which the highest level output feature of the vibrator101can be obtained, that is, in the position in which, as described after, the highest level of ultrasonic elliptic vibration of the vibrator101is performed.

Furthermore, in one side101-3of the vibrator101, in the central portion of the vibrator101, that is, in the vicinity (in this embodiment, the portion is referred to as a “node”) of the stationary point in the primary vertical vibration and the secondary curving vibration, described later, as the vibration mode, the pin member113for bringing out output power of the vibrator101is fixed to the side101-3as substantially normal.

Thus, as described later, when the traveling force is transmitted from the vibrator101to the third movable lens frame19, only the traveling force (self-moving force) can be transmitted to the third movable lens frame19without transmitting the vibration of the vibrator101to the third movable lens frame19without permission.

The pin member113for the retrieval of the traveling output can be any hollow or rigid member having a section of circle, square or any other optional shapes.

Thus, the characteristic of the shape and the material of the transmission member of the drive force for traveling the lens frame are simple construction, the production cost can be reduced, and the assemble work is very easy.

FIGS. 11A and 11Bare perspective views for explanation of the ultrasonic elliptic vibration of the vibrator101. First, when an alternating voltage about the frequency of 160 kHz is applied with the same phases to the A-phase and B-phase electrode of the vibrator101shown inFIG. 10, the primary vertical vibration is pumped to the vibrator101. When an alternating voltage about the frequency of 160 kHz is applied with the opposite phases to the A- and B-phase electrodes, the secondary curbing vibration is pumped the vibrator101.

When these vibrations are analyzed by a computer using a finite-element method, the resonant vertical vibration posture as shown inFIG. 11Aand the resonant curving vibration posture as shown inFIG. 11Bare anticipated. Then, the result of the ultrasonic vibration measurement has proved the anticipation.

The elliptic vibration composed from these vertical vibration and the curving vibration of the vibrator101works on the two guide shafts103through the four self-moving contact parts102, and, as the reaction of the work, the vibrator101moves forward and backward between the two setting portions104-2of the support portion104along the two guide shafts103. This is the operation principle of the ultrasonic linear motor according to the present invention.

In the ultrasonic linear motor100shown inFIGS. 9A and 9B, the lower guide shaft103-2in the two upper and lower guide shaft103enclosing the vibrator101vibrating as shown inFIGS. 11A and 11Bthrough the self-moving contact part102is supported by the shaft long bearing hole106of the support portion104but is not fixed, and the displacement of the both ends is suppressed by the shaft long bearing hole106in horizontal direction, but the vertical movement is propped up by the coil spring108, and can be moved within the range of the shaft long bearing hole106.

Therefore, especially when the vibrator101is close to one of the setting portion104-2between the upper and lower guide shaft103, the upper and lower guide shaft103are not relatively parallel (the sides where the vibrator101is not located are closer), and some self-moving contact parts102do not contact the guide shaft103.

However, although a part of the self-moving contact part102can be separate from the guide shaft103, it is not a definite problem for the moving operation of the vibrator101. For example, the four self-moving contact parts102(refer toFIG. 9B) contact the two guide shafts103between the two support portions104, that is, at the center of the moving operation of the vibrator101, but when the vibrator101is moved to the leftmost position, the lower left self-moving contact part102-2is somewhat upheld from the lower guide shaft103-2, and when the vibrator101is moved to the rightmost position, the lower right self-moving contact part102-2is somewhat upheld from the lower guide shaft103-2. In this case, the self-moving contact part102-2which is not upheld (lower right when it is located in the leftmost position) contacts the lower guide shaft103-2, performs a elliptic vibration, and becomes the source of the traveling force of the vibrator101. Therefore, the self-moving contact part102can obtain the traveling force of the vibrator101if any two or three units contact the upper and lower guide shaft103.

FIG. 12Ais a perspective view for explanation of the coupling method between the ultrasonic linear motor100and the third movable lens frame19.FIG. 12Bis a perspective view showing the retrieved leaf spring used in the coupling.FIG. 12Cis a perspective view of the retrieved coupling portion only.

FIG. 12Ais a perspective view of the ultrasonic linear motor100and the third movable lens frame19diagonally above from the left ofFIG. 4. In the explanation below by referring toFIGS. 12A,12B, and12C, the direction, that is, up and down, left and right, forward and backward, is based onFIGS. 12A,12B, and12C, but notFIG. 4.FIG. 12Ashows the pin member113for retrieval of the traveling output fixed as inserted inside from the center of the pin fixed face at the upper left of the vibrator101for understanding easily.

As shown inFIG. 12A, the third movable lens frame19comprises the lens frame body114for holding the third movable lens unit12, the bearing53-3, and an engagement projection unit115projecting downward from the bearing53-3. Around the center of the engagement projection unit115, a long hole116is set parallel to the second optical axis O2in the traveling direction of the lens frame body114.

The long hole116is engaged with a leaf spring117for propelling the pin member113for retrieval of traveling output to the contact portion (long hole116of the engagement projection unit115) with the third movable lens frame19.

The leaf spring117comprises a flat body unit117-1, an engagement unit117-2directed in two directions from below to the front and upward of the body unit117-1, and a propelling unit117-3directed from left of the body unit117-1to the front.

The engagement unit117-2of the leaf spring117is engaged with the engagement projection unit115by enclosing the lower end portion of the engagement projection unit115in which the long hole116of the third movable lens frame19is formed wraparound from the back. Thus, the body unit117-1of the leaf spring117tightly contacts the aperture of the long hole116, and the propelling unit117-3is inserted into a predetermined position in the long hole116from the farther side.

Between the propelling unit117-3and the left end portion of the long hole116, there is space enough for the pin member113for retrieval of traveling output to be inserted.

Between the farther surface of the third movable lens frame19and the lens frame body114and the surface of front side of the engagement projection unit115, there is space enough for the ultrasonic linear motor100to be arranged. When the ultrasonic linear motor100is arranged in the space, the pin member113for retrieval of the traveling output is inserted into the space formed between the propelling unit117-3and left end of the long hole116as shown inFIG. 12C.

The engagement prohibits the pin member113for retrieval of the traveling output from moving to the direction of the second optical axis O2in the long hole116, but allows it for idle space in moving ups and downs.

The idle space allows the displacement, etc. of the attachment positions between the vibrator101and the two guide shafts103to be absorbed.

Thus, the pin member113for retrieval of the traveling output correctly transmits the movement and the force of the vibrator101in the direction of the second optical axis O2to the third movable lens frame19, and the up and down movement by the elliptic vibration of the vibrator101is absorbed by the up and down movement in the long hole116, and is not transmitted to the third movable lens frame19. Therefore, there is no possibility of the displacement of a subject image at focusing.

Thus, according to the present embodiment, when the vibrator101is coupled with the third movable lens frame19, one point is fixed to the vibrator101, and the other point only touches the touch point (the long hole116of the engagement projection unit115) to the third movable lens frame19by the propelling force of the leaf spring117, thereby forming the coupling status by the pin member113for retrieval of the traveling output. Thus, the traveling force (drive force) of the vibrator101is transmitted to the travel of the third movable lens frame19.

According to the present embodiment, a pin of a pillar member is set as a running transmission member at the side center of the vibrator for making vertical vibration and elliptic vibration. However, the application is not limited to this, but other vibration mode or the composite of other vibration modes are used for a vibrator. In this case, the vibration of a vibrator can be transmitted to a lens frame of traveling (running) power without interference with the vibration of the vibrator so far as a pin is arranged at a common node for the vibration mode or a point where the vibration is minimized.

FIGS. 13A and 13Bare the perspective views showing the other method of coupling the ultrasonic linear motor100(the vibrator110) and the third movable lens frame. As shown inFIG. 13A, a round hole118and a long hole119are formed side by side in the direction of the second optical axis O2at the catching raised portion115of the third movable lens frame19.

In the present embodiment, the single rigid holding member200replaces the pin member113for retrieval of the traveling output and the leaf spring117. The rigid holding member200comprises a base portion201of a rectangular plate, a convex portion202(202-1,202-2) formed in two positions on the back of the base portion201, a holding portion203(203-1,203-2) provided from both end portions in longitudinal direction from side to side of the base portion201approximately on the square in the short. Inside the holding portion203, for example, a elastic member204made of silicon rubber, etc. is adhered.

The convex portion202-1is positioned by holding with the round hole118of the catching raised portion115, and the convex portion202-2is engaging with the long hole119and is suppressed the rotation, thereby the rigid holding member200is fixed by adhesion.

When an ultrasonic linear motor100is arranged in the space formed between the side beyond the main lens frame114of the third movable lens frame19and this side of the catching raised portion115, the above-mentioned rigid holding member200holds the two contour planes101-5and101-6normal to the running direction (traveling direction) of the vibrator101as shown inFIG. 13Busing the holding portion203through the elastic member204adhered to the inside, thereby coupling the vibrator101to the third movable lens frame19.

Thus, by the rigid holding member200holding the vibrator101through the elastic member204, the displacement, etc. made between the above-mentioned vibrator101and the two guide shafts103during the attachment can be absorbed, thereby preventing excess external force from being applied to the vibration characteristic of the vibrator101.

The holding portion203of the rigid holding member200enters the space between the two guide shafts103-1and103-2arranged parallel to the ultrasonic linear motor100, and encloses the vibrator101.

Thus, with the configuration shown inFIG. 13, the self-moving force (traveling force) of the vibrator101of the ultrasonic linear motor100can be transmitted to the third movable lens frame19. In addition, inFIG. 13, the rigid holding member200is provided separate from the third movable lens frame19. However, the present invention is not limited to this application, but the third movable lens frame19can be incorporated into the rigid holding member200.

FIGS. 14A and 14Bare perspective views showing another method of coupling (the vibrator101of) the ultrasonic linear motor100with the third movable lens frame19.

The configuration of the engagement projection unit115of the third movable lens frame19shown inFIG. 14Ais the same as shown inFIG. 13A. In the present embodiment, the rigid holding member200is replaced with an elastic holding member200′.

The elastic holding member200′ is entirely formed by an elastic member such as a basic portion201′, a convex portion202′ (202′-1202′-2), an holding portion203′ (203′-1,203′-2), etc. Therefore, it is not necessary to adhere the elastic member204in the holding portion203′ (203′-1,203′-2) as in the case shown inFIG. 13.

As an elastic member forming the above-mentioned elastic holding member200′, for example, polyester elastomer, etc. can be used.

With the above-mentioned configuration, the self moving force (locomotive faculty) of the vibrator101of the ultrasonic linear motor100can reach the third movable lens frame19.

When the drive transmission member to the third movable lens frame19of the vibrator101is configured as the holding member shown inFIG. 13orFIG. 14, it has advantages of that it is not necessary to perform mechanical processing for mounting the pin member113for retrieval of the traveling output on the vibrator101.

InFIGS. 13 and 14, the vibrator101is enclosed by elastic means. However, when high precision is not requested for the stop position of a mobile object (third movable lens frame19according to the present embodiment) driven by the ultrasonic linear motor100, there is no problem if there is some space between the holding member and the vibrator. In this case, it is not necessary that the holding member has to be made of an elastic member.

FIG. 15is a partial exploded perspective view showing the detailed configuration of the magnetic sensor unit47shown inFIGS. 3 and 4together with the ultrasonic linear motor100into which the magnetic sensor unit47is incorporated and the third movable lens frame19.

The magnetic sensor unit47is provided for detecting the transfer distance of the third movable lens frame19from the initial position after the photo-sensor73shown inFIG. 3detects the initial position of the third movable lens frame19.

As shown inFIG. 15, the ultrasonic linear motor100is arranged between the side of the lens frame body114of the third movable lens frame19and the engagement projection unit115as described inFIGS. 12 and 13. Then, inFIG. 15, the ultrasonic linear motor100is fixed to the metal frame23atogether with a magnetic sensor holder205(205-1,205-2).

A engaging unit206-1of a leaf spring206is engaged with the horizontal plane unit205-1of the magnetic sensor holder205, and the vertical plane unit205-2of the magnetic sensor holder205holds a magnetic sensor207. A detection unit207-1is formed to detect magnetic substantially at the center of the magnetic sensor207. From above the detection unit207-1, four electrode lead wires209are obtained with an electric connection with the magnetic sensor207enforced by an adhesive agent208.

An engaging unit210-1of a magnetic scale210is adhered to a scale holding unit115-1forming a flat portion as projecting outside (diagonally lower right inFIG. 15) at a predetermined step from the engagement projection unit115rising (in the form set below because it is viewed upside down inFIGS. 12 through 14) from the bearing53-3of the third movable lens frame19, thereby fixing the magnetic scale210to the scale holding unit115-1with the scale surface facing the detection unit207-1of the magnetic sensor207.

The magnetic scale210is formed by an elastic sheet member, for example, a resin sheet of polyester, etc. A magnetic is applied to the scale surface, and the magnetic is magnetized at predetermined intervals. To allow the magnetic sensor207to read the magnet, it is desired that the scale surface of the magnetic scale210is closest possible to the detection unit207-1of the magnetic sensor207.

The magnetic scale210is fixedly mounted on the third movable lens frame19through the scale holding unit115-1while the magnetic sensor207is fixed to the metal frame23afor which the third movable lens frame19are arranged as movable along the two guide shafts (65,68) as described above, thereby arranging the magnetic sensor207and the magnetic scale210as relatively movable.

As shown inFIG. 15, the magnetic scale210configuring the encoder and the magnetic sensor207are laid on the side of the third movable lens frame19together with the ultrasonic linear motor100moving and driving the third movable lens frame19.

Furthermore, the positional relationship between the ultrasonic linear motor100and the encoder is described below. That is, as described before, the ultrasonic linear motor100is provided between the lens frame body114of the third movable lens frame19and the engagement projection unit115where the coupling member such as the pin member113, the leaf spring117, etc. are arranged, and the magnetic sensor207is arranged substantially parallel to the second optical axis O2outside the engagement projection unit115of the third movable lens frame19. Thus, the device can be downsized.

On the reverse of the magnetic scale210, as shown inFIG. 15, it is desired that non-magnetic metal foil211with a smooth surface is adhered. The magnetic scale210to which the metal foil211is adhered is fixed to the scale holding unit115-1by the engaging unit210-1.

Furthermore, the leaf spring206is provided with a spring unit206-2extending downward from the engaging unit206-1and horizontally extending like a hook. At the end of the spring unit206-2, a dome-shaped convex portion206-3projecting toward the magnetic scale210is formed. The convex portion206-3is formed in the position corresponding to the detection unit207-1of the magnetic sensor207.

By the engaging unit206-1of the leaf spring206being fixed to the metal frame23atogether with the magnetic sensor holder205-1, the convex portion206-3of the leaf spring206presses the portion not fixed to the engaging unit210-1of the magnetic scale210, that is, a free end side210-2through the metal foil211against the detection unit207-1of the magnetic sensor207.

Thus, the scale surface of the magnetic scale210relatively moves while sliding to the detection unit207-1of the magnetic sensor207.

Thus, by the scale surface of the magnetic scale210contacts and moves to the detection unit207-1of the magnetic sensor207, the magnetic sensor207can more correctly read the scale of the magnetic scale210.

Furthermore, since the portion of the leaf spring206pressing the back of the scale surface through the metal foil211is formed by the dome-shaped convex portion206-3, the friction resistance with the metal foil211can be minimized, thereby reducing the resistance load generated by the pressure.

Since the non-magnetic metal foil211having a smooth surface is adhered to the pressed back of the scale surface, the wear by the friction with the leaf spring206can be reduced, thereby prolonging the life of the device.

FIG. 16shows an example of a variation of the above-mentioned magnetic sensor unit. The magnetic sensor unit shown inFIG. 16has a resin layer212on the back of the scale surface replacing the metal foil211adhered to the back of the scale surface of the magnetic scale210as shown inFIG. 15. The resin layer212can be formed by, for example, fluorine resin, etc. Since resin produces a smooth surface with less friction resistance, and is very smooth, the resin layer212can also reduce the resistance load generated by the pressure.

FIG. 17shows an example of a variation of a magnetic sensor unit. In the example shown inFIG. 17, the leaf spring206shown inFIGS. 15 and 16is replaced with an nonmagnetic elastic metal sheet213integrally placed on the opposite side of the scale surface of the magnetic scale210.

The elastic metal sheet213is directed at an angle θ smaller than 180° from the central point such that both ends are closer to the magnetic sensor207than the center. At the end portion of the engaging unit210-1of the magnetic scale210, it is incorporated into the magnetic scale210.

Thus, using the property of the spring of the elastic metal sheet213, the magnetic scale210is appropriately pressed against the magnetic sensor207, thereby propelling the variable portion of the scale surface of the magnetic sensor207to contact the detection unit207-1of the magnetic sensor207.

The elastic metal sheet213is not limited to metal, but can be a resin elastic sheet.

The scale holding unit115-1of the third movable lens frame19can also be configured such that the free end side of the magnetic scale210can be closer to the magnetic sensor207by inclining the magnetic scale210to be held by the scale holding unit115-1by lowering the step on the magnetic sensor207side to form the slope surface115-2inclined from upper right to lower left with one end of the magnetic scale210fixed to the slope surface115-2.

In this case, the elastic metal sheet213is adhered to the back of the magnetic scale210without bending it.

Thus, the magnetic scale210can stably contact the detecting unit207-1of the magnetic sensor207without a pressing member, etc. such as the leaf spring206shown inFIG. 15, thereby reducing the cost and downsizing the entire device.

With any configuration shown inFIGS. 15 through 17, the friction resistance between the magnetic sensor207and the magnetic scale210can be reduced by elastically pressing the magnetic scale210against the magnetic sensor207, and a desired position signal can be obtained by magnetism with a simple configuration while absorbing the displacement from the magnetic sensor207when the third movable lens frame19moves.

As described above, according to the present invention, a support portion can be configured by a metal frame and a mold unit incorporated into the metal frame, and so much so that all members are supported by the support portion comprised by metal frame and a mold part molded integral with the metal frame and are arranged without excess space along the optical axis directed almost on the square in the longitudinal direction after incoming from the short direction of the device body, the lens-implement can be slimmer and the digital camera containing the lens-implement can be the slimmer.

Since the forward-backward movement of the zoom movable lens frame can be performed by a long shaft cam having cam grooves around, the shaft cam is arranged parallel to the two guide shafts supporting the entire lens frame along the forward-backward movement of the movable lens frame for a zoom, and close to the lens frame, and the drive source of the shaft cam is arranged using the idle space on the back of the prism for bending the direction of the optical axis, the axial form members are adjacent and parallel to each other, and the drive source is arranged in the idle space. Therefore, a lens-implement and a digital camera using the lens-implement provided a zoom mechanism provided the slim structure of the lens mechanism of the bent-optical-axis optical system are able to realize to holdout.

Furthermore, since a ultrasonic linear motor with a self-moving vibrator is loaded, and the vibrator and the lens frame can be coupled with a pin member or an holding member, a lens-implement having the configuration appropriate for a ultrasonic linear motor and a simple coupling mechanism and a digital camera with the lens-implement can be provided.

Additionally, so much so that the scale surface of the magnetic scale and the detection unit of the magnetic sensor slide on each other by elastically pressing the magnetic scale against the magnetic sensor in the magnetic scale and the magnetic sensor forming an encoder, the friction resistance between the magnetic sensor and the magnetic scale can be reduced with a simple configuration, the displacement from the magnetic sensor when the movable lens frame moves is absorbed, the magnetic sensor constantly and correctly reads the magnetic scale, and a desired position signal of the movable lens frame can be obtained. Therefore, an encoder capable of detecting a correct transfer position all the time, a lens-implement having the encoder, and a digital camera having the lens-implement can be successfully provided.