JPH0584914U - Brush position adjustment device for zoom lens barrel - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a brush position adjusting device for a zoom lens barrel capable of flexibly adjusting a relative position between a code plate and a brush. A focal length change due to zooming is detected by a code plate fixed to one or the other of the linear movement member and the fixed member and a brush in contact with the code plate, and the detected focal length information is transmitted through the FPC board to the camera body. In the zoom lens barrel that transmits to the side, the brush support member having the brush and the code plate, respectively, a fixing member,
A linear movement member that linearly moves in the optical axis direction along with zooming is provided, and spring means for urging the brush support member in a direction of separating from the fixed member and a brush support member against the spring means are provided. A brush position adjusting device provided with a mounting screw for supporting a fixed member.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention detects a change in focal length due to zooming by means of a code plate fixed to one or the other of the rectilinear movement member and the fixed member and a brush in contact with the code plate, and the detected focal length information is transmitted via the FPC board to the camera. The present invention relates to a brush position adjusting device for a zoom lens barrel that is transmitted to the body side.

[0002]

[Prior art and its problems]

 For example, in a lens barrel that zooms by driving a cam ring, as a means for detecting the focal length during zooming, a zoom code plate attached to the fixed ring of the lens that converts the focal length into an electrical signal, and zooming. A zoom brush is used, which is provided on a cam ring that rotates at times and makes sliding contact with the zoom code plate as the cam ring rotates. A pattern contact is formed on the zoom code plate, and during zooming, the zoom brush rotates with the cam ring and slides on the zoom code plate, which causes a digital signal corresponding to the focal length to be sent to the camera operation control circuit side. Is output. Based on the detected focal length information, data corresponding to the focal length at that time is input to the camera operation control circuit from the data table prepared for each variable information. Therefore, if the installation positions of the zoom brush and zoom code plate are not set to the correct reference positions, the rotational position of the cam ring with respect to the fixed ring of the lens will not be set, which may cause an error in the focal length during zooming. become.

However, in the conventional zoom lens barrel, a zoom code plate is attached along the circumferential direction of the outer peripheral surface of the fixed ring, and the zoom brush fixed to the cam ring is fixed on the zoom code plate. It is configured to rotate in the circumferential direction of the ring, and it has been extremely difficult to make fine adjustments to the optimum reference position by shifting the relative positions of the zoom code plate and the zoom brush, for example, when manufacturing a product. For this reason, it is necessary to set the position of the zoom code plate and the zoom brush slidingly in contact with the zoom code plate and their shapes with extremely high accuracy, which also causes a cost increase.

[0004]

[The purpose of the device]

 The present invention has been made based on the above awareness, and provides a brush position adjusting device for a zoom lens barrel capable of flexibly adjusting the relative position between the code plate and the brush. The purpose is to

[0005]

[Outline of the device]

 The present invention that achieves the above object, therefore, changes the focal length change due to zooming by a linearly moving member that moves linearly in the direction of the optical axis with zooming, and a code plate that is fixed to one or the other of the fixing members and a contact with the code plate. In the zoom lens barrel that detects the detected focal length information through the FPC board to the camera body side, the brush support member having the brush and the code plate are moved straight with the fixed member. Each of the members is provided with a spring means for urging the brush supporting member in a direction to separate it from the fixing member, and a mounting screw for supporting the brush supporting member on the fixing member against the spring means. Have.

[0006]

【Example】

 The present invention will be described below with reference to the illustrated embodiments. First, the entire zoom lens barrel to which the present invention is applied will be described with reference to FIGS.

A helicoid ring 12 is fixed to a fixed lens barrel 11 integrated with the camera body, and a female multi-thread screw 12 a of the helicoid ring 12 is attached to a male multi-thread screw 10 a formed on the outer peripheral surface of the cam ring 10. Are screwed together. A female multi-start screw 10b and an inner cam groove 10c are formed inside the cam ring 10, and a male multi-start screw 13a of the front lens barrel 13 is screwed into the female multi-start screw 10b. Light shielding plates 25, 26 having openings 25d, 26d corresponding to the apertures are located at the rear end of the cam ring 10, respectively, and a positioning recess 25a formed above the light shielding plates 25, 26. , 26a and the positioning recess 15b of the linear guide ring 15 are fitted with the guide portions 23b of the linear guide 23 fixed to the camera body side. Light-shielding plates 25 and 26 are fixed to the linear guide ring 15 with the positioning recesses 25a and 26a aligned with the positioning recess 15b, and the cam ring 10 is rotatably fitted to the linear guide ring 15. Be touched. The straight guide 23 is fixed to the fixing member 24 fixed to the camera body side by a screw 22 so that the guide portion 23b is projected along the optical axis direction.

A shutter holding frame 13c having a rear end portion of an annular shutter unit 16 fixed thereto is fixed to the front lens group cylinder 13, and a helicoid ring 17 integrally provided on the inner peripheral portion of the shutter unit 16. A front lens group frame 18 that holds the front lens group is screwed into this. The shutter unit 16 has its drive pin 16a engaged with a driven pin 18a integrated with the front lens group frame 18. As is well known, the drive pin 16a is rotationally driven by an angle according to the distance measurement signal from the distance measuring device, and this rotation is transmitted to the front lens group frame 18 via the driven pin 18a, and the front lens group frame 18 ( While the front lens unit L1) rotates, it moves in the optical axis direction for focusing. The shutter unit 16 opens and closes the shutter blade 16b according to the brightness signal of the subject. In addition, 13f in FIG. 11 is a lens aperture.

The rear group lens frame 19 supporting the rear group lens L2 has a cam pin 19a protruding in the radial direction, and the cam pin 19a is fitted in the inner cam groove 10c formed on the inner surface of the cam ring 10. waiting. The rear lens group frame 19 and the shutter holding frame 13c are linearly guided by a linear guide surface 15a formed on the linear guide ring 15. FIG. 11 shows the rectilinear guide surface 15a of the rectilinear guide ring 15 and the rectilinear guide surface 19b of the rear lens group frame 19 which are engaged with each other.

The cam pin 19a of the rear lens group frame 19 is fitted into the recess 13b formed in the rear end surface of the front lens barrel 13 during assembly. This is a structure for fitting the cam pin 19a into the inner cam groove 10c at the same time when the male multiple thread 13a on the outer periphery of the front lens barrel 13 is screwed into the female multiple thread 10b of the cam ring 10. After the assembling, the front group lens barrel 13 moves in the optical axis direction independently of each other by the rotation of the cam ring 10, the front group lens barrel 13 following the multiple threads 10b and 13a, and the rear group lens frame 19 following the cam groove 10c.

That is, in the zoom lens barrel having the above structure, when the cam ring 10 is rotationally driven, the cam ring 10 itself moves in the optical axis direction in accordance with the relationship between the male multiple thread 10a and the female multiple thread 12a. At the same time, the front group lens barrel 13 (front group lens L1) is moved to the optical axis by the screwing relationship between the female multi-thread screw 10b and the male multi-thread screw 13a and the linear guide mechanism of the shutter holding frame 13c and the linear guide ring 15. Go straight in the direction. Also, when the cam ring 10 rotates, the relationship between the cam groove 10c on the inner surface of the cam ring 10 and the cam pin 19a provided on the rear lens group frame 19 and the rectilinear guide mechanism of the rear lens group frame 19 and the rectilinear guide ring 15 cause the rear lens group to move. The zoom frame 19 (rear group lens L2) moves in the optical axis direction for zooming.

The cam ring 10 is formed with a male multi-thread screw 10a and a plurality of threads of gears 10d parallel to each other, which are located at the rear part of the cam ring 10 (see FIG. 11). The gear 10d is composed of a spur gear whose teeth are parallel to the axis of the cam ring 10 and is inclined in the same direction as the mountain direction of the male multi-thread screw 10a. A single thread ridge 10a 'is formed on the male multi-thread screw 10a. In other words, the male multi-thread screw 10a is cut off at a part of its circumferential direction except for one thread 10a ', and the cut portion is provided with the gear 10d. In this embodiment, the male multi-start screw 10a is a triple-start screw, and a gear 10d is provided at the cut-out portion of the two-start screw. The axially formed lengths s of these male thread 10a, one thread 10a 'and gear 10d are the same.

On the inner surface of the helicoid ring 12, a female multi-thread screw 12a and a clearance groove (not shown) corresponding to the male multi-thread screw 10a of the cam ring 10, the single thread 10a 'and the triple gear 10d, respectively. Etc. are formed. That is, the gear 10d moves without contact in the clearance groove when the cam ring 10 rotates in accordance with the engagement of the male multi-thread screw 10a (thread 10a ') and the female multi-thread screw 12a.

The helicoid ring 12 has a notch 12d on its side surface, and a pinion (not shown) located in the notch 12d meshes with the gear 10d. This pinion has an axial length that allows it to mesh with the three gears 10d at the same time, but at the front and rear moving ends of the cam ring 10, only the rearmost and frontmost gears 10d, respectively. Mesh with. The pinion is located at a fixed position in the cutout 12d and is rotationally driven by a drive motor (not shown).

The adjusting device is provided on the inner surface of the zoom mechanism zoomed by the rotation of the rotationally driven cam ring 10 and the inner surface of the front lens group barrel 13 (the straight moving member) that moves straight in the optical axis direction by the zoom mechanism. A zoom code plate (code plate) 36 provided, a brush support member 40 having a zoom brush 41 (brush) that contacts the zoom code plate 36 and detects the current focal length, and the brush support member 40. The brush position adjusting device for adjusting the position in the optical axis direction and the cam ring 10 whose reference rotational position changes with the adjustment of the brush position by the brush position adjusting device are at predetermined predetermined rotating positions. And a cam ring position confirmation means for confirming that.

As shown in FIG. 5, pattern contacts are formed on the zoom code plate 36, and during zooming, the zoom code plate 36 moves forward and backward along with the front lens barrel 13 in the optical axis direction to zoom. Since the position of the brush 41 is changed, a digital signal corresponding to the current focal length is output to the camera operation control circuit (not shown) based on this position. Based on this focal length signal, data corresponding to the focal length at that time is input to the camera operation control circuit from the data table prepared for each variable information.

An insertion groove 13e is formed in a part of the inner peripheral surface of the front lens barrel 13 in parallel with the optical axis O. One end of the zoom code plate 36 is provided on the side of the insertion groove 13e near the photographing opening 13f. An engagement protrusion 13d for engaging the positioning hole 36a formed in the portion is formed. The position of the zoom code plate 36 is determined in parallel with the optical axis direction by engaging the positioning hole 36a with the engaging protrusion 13d, and the back surface thereof is fixed by being stuck to the insertion groove 13e.

As shown in FIG. 7, the brush support member 40 constituting the brush position adjusting device is made of a synthetic resin material formed in an inverted L shape in a side view, and is made of a straight guide ring 15 (fixing member). It has a contact portion 40b that should contact the support portion 15c formed in part, and a positioning portion 40c that positions and supports the four zoom brushes 41 corresponding to the pattern contacts of the zoom code plate 36. .. The support portion 15c has an insertion hole 33 into which the mounting screw 31 is inserted, and the contact portion 40b has a female screw hole 40a corresponding to the insertion hole 33. Further, the zoom brush 41 has an output side terminal 41a at one end which should come into contact with the terminal 37a of the flexible substrate 37 when the brush support member 40 is attached to the support portion 15c by the attachment screw 31. It has an input side terminal 41b slidably contacting with 6 at the other end.

A spring insertion hole 32 is formed adjacent to the screw insertion hole 33 in the support portion 15c so as to penetrate toward the contact portion 40b similarly to the screw insertion hole 33 (FIG. 11). In the spring insertion hole 32, the separation spring 30 (spring means) whose one end is in contact with the brush supporting member 40 and the other end is in contact with the light shielding plate 25 is contracted, so that the brush supporting member 40 is While being supported by the support portion 15c, the support portion 15c is urged in a direction away from the support portion 15c. In the assembled state, the screw insertion hole 33 is exposed from an insertion hole 26c formed in the light shield plate 26 so as to correspond to the screw insertion hole 33 of the linear guide ring 15, and the insertion hole 26c is the aperture A (see FIG. 7)), the screw insertion hole 33 can be exposed when the back cover (not shown) is opened. As a result, when the mounting screw 31 is rotated in an appropriate direction and tightened or loosened in a state where the brush supporting member 40 is supported by the supporting portion 15c, the brush supporting member corresponding to the rotation amount of the mounting screw 31. 40, that is, the input side terminal 41b can be slid with respect to the zoom code plate 36. Therefore, the relative position between the zoom code plate 36 and the zoom brush 41 can be easily adjusted by opening the back cover (not shown) of the camera and rotating the mounting screw 41 appropriately. It is not necessary to set the precision with respect to the positions and shapes of the zoom code plate and the zoom brush like the above, and it is possible to expect cost reductions accompanying this.

On the other hand, as shown in FIG. 1, a sliding groove 38 for accommodating the brush supporting member 40 and the zoom brush 41 is formed in one of the three rectilinear guide surfaces 15a having the supporting portion 15c. Has been done. The sliding groove 38 is formed to have substantially the same size as the width of the brush supporting member 40, and a regulation wall 39 is formed in the substantially central portion thereof. A flat surface 15e (FIG. 2) is formed on the outer side of the supporting portion 15c, and the terminal portion 37a of the flexible substrate 37 is placed on the flat surface 15e and the zoom brush 41 is mounted on the terminal portion 37a. The output side terminal 41a is elastically contacted. When mounting the zoom brush 41 in the sliding groove 38, first, the output side terminal 41a is inserted into the flat surface 15e side, the brush support member 40 is fitted in the sliding groove 38, and the input side terminal of the zoom brush 41 is further inserted. The vicinity of 41b is brought into contact with the back surface of the regulation wall 39. At this time, the terminal portion 37a is sandwiched between the output side terminal 41a and the flat surface 15e. As a result, the zoom brush 41 is connected to the flexible substrate 37 connected to the camera operation control circuit side.

As shown in FIG. 11, guide holes 15d are formed on the left and right sides of the support portion 15c of the linear guide ring 15, and the guide holes 15d are formed on the left and right sides of the brush support member 40. By inserting the guide protrusion 40d slidably, the input side terminal 41b can be slid very smoothly with respect to the zoom code plate 36 without being displaced.

The relative positions in the optical axis direction of the zoom code plate 36 and the zoom brush 41 that is in sliding contact with the zoom code plate 36 are specific pattern contact points of the zoom code plate 36 at this focal length when a certain predetermined focal length is considered. The absolute position of the zoom brush 41 with respect to. When the zoom code plate 36 and the zoom brush 41 function properly, the zoom cord plate 36 is designed so that zooming can be properly performed as planned by the screwing relationship between the female multi-thread screw 10b and the male multi-thread screw 13a. If the relative positions of the zoom brush 41 and the rectilinear movement inner ring 15 in the optical axis direction change due to manufacturing errors or the like, the relative positions of the rectilinear guide ring 15 and the zoom code plate 36 change accordingly. However, the rotational position of the cam ring 10 that rotates in accordance with the movement of the zoom brush 41 at a predetermined focal length changes.

Therefore, the position of the zoom brush 41 in the optical axis direction is adjusted at an appropriate position of the front group lens barrel 13, for example, at the storage position where the lens barrel is contracted to the maximum, and the brush position is adjusted in accordance with the adjustment. A cam ring position confirming means capable of confirming that the cam ring 10 whose reference rotation position changes is located at a predetermined scheduled rotation position, in other words, that the cam ring 10 is at the predetermined scheduled rotation position. Is required.

The cam ring position confirmation means will be described with reference to FIGS. 6 and 7. The light shielding plates 25 and 26 have fixing screws 44 inserted into screw holes 25b and 26b formed at corresponding positions, and the fixing screws 44 are screwed into the screw holes 43 of the rectilinear guide ring 15 to cause the rectilinear movement. It is fixed to the guide ring 15. The shading plate 25 has a viewing window 25e to the left of the positioning recess 25a, and the shading plate 26 has a viewing window 26e at a position corresponding to the shading plate 25e. The light shielding plates 25 and 26 are configured to have a shape larger than a surface of the straight guide ring 15 facing rearward of the optical axis and not protruding outward from the outer peripheral edge of the cam ring 10, and the viewing windows 25e and 26e are respectively formed. The cam ring 10 is formed in a slightly elongated shape corresponding to the rear end face 10e and along the circumferential direction of the rear end face 10e. Further, on the rear end surface 10e of the cam ring 10, a mark 45 consisting of two points, which should be exposed only at the planned turning position of the cam ring 10, is formed in the peep window 26e (25e).

When the linear guide ring 15 is properly arranged with respect to the camera body, it becomes as shown in FIGS. 6 and 7 with the positioning recess 15b facing upward. For example, at the time of manufacturing, in this state, a driver (not shown) is inserted through the insertion hole 26c of the light shielding plate 26, and the mounting screw 31 screwed into the screw insertion hole 33 is turned clockwise or counterclockwise. When moved, the brush position adjusting device can be mechanically operated. At this time, the camera body assembled in a predetermined state is set in an inspection device for inspecting the accuracy of the product, and a drive motor (not shown) is driven in association with the slide of the zoom brush 41. In other words, by sliding the input side terminal 41b with respect to the zoom code plate 36, the drive motor is driven, and the cam ring 10 is rotated via the gear 10d in the same manner as when the camera assembly is completed. You can

As a result, according to the engagement of the male multi-thread screw 10a (thread 10a ') and the female multi-thread screw 12a, etc., the cam ring 10 rotates forward and backward in the optical axis direction, and the front lens group L1 and the rear lens group L1. The relative position to the lens L2 is changed and zooming is performed. At this time, the mark 45 on the rear end surface 10e of the cam ring 10 is formed at a position that should be exposed from the observation window 26e when the input side terminal 41b of the zoom brush 41 is properly positioned with respect to the zoom code plate 36. Therefore, when the mark 45 is positioned with respect to the viewing window 26e as shown in FIG. 2, the mounting screw 31 is rotated by looking through the viewing window 26e and appropriately rotating the mounting screw 31 with a driver. By stopping, it is possible to confirm that the cam ring 10 is properly positioned at the predetermined scheduled rotation position.

This confirmation operation is performed as shown in FIGS. 8A and 8B, in addition to the case where the two marks 45 are completely accommodated in the observation window 26e as shown in FIG. The entire one of the pair of marks 45 and half or more of the other mark may be accommodated in the viewing window 26 e.

The shape of the mark 45 and the shape of the viewing window 26e (25e) are not limited to the shape of this embodiment. In short, it is sufficient that the relative rotational positional relationship of the cam ring 10 with respect to the light shielding plates 25 and 26 can be visually confirmed.

[0029]

[Effect of the device]

 As described above, according to the brush position adjusting device for a zoom lens barrel of the present invention, the relative position between the cord plate and the brush can be easily adjusted by appropriately rotating the mounting screw. This eliminates the need to set the positions of the zoom code plate and the zoom brush and their shapes with high accuracy, unlike the conventional one, and the cost reduction can be expected.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a main part of a brush position adjusting device of the present embodiment.

FIG. 2 is a side sectional view showing a main part of the brush position adjusting device of FIG.

FIG. 3 is a perspective view showing a zoom code plate arrangement structure on the inner surface of the front lens barrel.

FIG. 4 is a diagram of a main part of FIG. 3 viewed from above.

FIG. 5 is a diagram showing a zoom code plate alone.

FIG. 6 is a perspective view showing a state where essential parts of the adjusting device are assembled.

FIG. 7 is a view of the adjusting device in a state where main parts are assembled, as viewed from the rear of the optical axis.

FIG. 8 is a schematic view showing a different state when the mark of the adjusting device is exposed on the peep window.

FIG. 9 is a cross-sectional view showing an example of a zoom lens barrel.

10 is a cross-sectional view of a main part of the zoom lens barrel in FIG.

11 is an exploded perspective view of a main part of the zoom lens barrel of FIG.

[Description of Reference Signs] 10 cam ring 11 fixed lens barrel 12 helicoid ring 13 front group lens barrel (straight moving member) 25a 26a positioning recess 15 straight guiding ring (fixing member) 15a straight guiding surface 15b positioning recess 15c supporting portion 15d guide hole 15e Flat surface 16 Shutter unit 17 Helicoid ring 19 Rear group lens frame 23 Linear guide 25 26 Light-shielding plate 25e 26e Viewing window 30 Separation spring (spring means) 31 Mounting screw 32 Spring insertion hole 33 Insertion hole 36 Zoom code plate (code plate) ) 37 flexible board (FPC board) 37a terminal portion 38 sliding groove 39 regulation wall 40 brush support member 40a female screw hole 40b contact portion 40c positioning portion 40d guide protrusion 41 zoom brush (brush) 41a output side terminal 41b input side terminal 45 Mark L2 Rear group lens L1 front lens group

Claims (2)

[Scope of utility model registration request] 1. A change in focal length due to zooming is detected by a rectilinear moving member that rectilinearly moves in the optical axis direction along with zooming, a code plate fixed to one or the other of the fixing members, and a brush in contact with this. In the zoom lens barrel that transmits the detected focal length information to the camera body side via the FPC board, the brush support member having the brush and the code plate are provided on the fixed member and the rectilinear movement member, respectively. A brush for a zoom lens barrel, characterized in that spring means for urging the support member away from the fixed member and mounting screws for supporting the brush support member on the fixed member against the spring means are provided. Position adjustment device. 2. The brush position adjusting device for a zoom lens barrel according to claim 1, wherein the mounting screw is provided so as to be rotationally adjustable with the back cover of the camera being opened.