CA1312758C - Lens driving apparatus - Google Patents
Lens driving apparatusInfo
- Publication number
- CA1312758C CA1312758C CA000566619A CA566619A CA1312758C CA 1312758 C CA1312758 C CA 1312758C CA 000566619 A CA000566619 A CA 000566619A CA 566619 A CA566619 A CA 566619A CA 1312758 C CA1312758 C CA 1312758C
- Authority
- CA
- Canada
- Prior art keywords
- lens
- cam
- lens holder
- cam disk
- optical axis
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B7/00—Mountings, adjusting means, or light-tight connections, for optical elements
- G02B7/02—Mountings, adjusting means, or light-tight connections, for optical elements for lenses
- G02B7/04—Mountings, adjusting means, or light-tight connections, for optical elements for lenses with mechanism for focusing or varying magnification
- G02B7/10—Mountings, adjusting means, or light-tight connections, for optical elements for lenses with mechanism for focusing or varying magnification by relative axial movement of several lenses, e.g. of varifocal objective lens
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
- G03B5/00—Adjustment of optical system relative to image or object surface other than for focusing
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
- G03B2205/00—Adjustment of optical system relative to image or object surface other than for focusing
- G03B2205/0046—Movement of one or more optical elements for zooming
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Lens Barrels (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A lens moving apparatus for use with a power zoom lens unit that enables a macro operation and offers reduced lens unit size has a single cam groove in a cam disk that is driven to rotate in a plane parallel to an optical axis. A
compensator lens holding member is moved parallel to the optical axis directly by the cam groove and an upraised pin is provided on the cam disk for engagement with a cam groove formed in the holding member for a variator lens, so that the variator lens is also moved parallel to the optical axis by the driving disk. The cam groove on the variator lens holding member is formed to permit movement of the compensator lens independently of the variator lens.
A lens moving apparatus for use with a power zoom lens unit that enables a macro operation and offers reduced lens unit size has a single cam groove in a cam disk that is driven to rotate in a plane parallel to an optical axis. A
compensator lens holding member is moved parallel to the optical axis directly by the cam groove and an upraised pin is provided on the cam disk for engagement with a cam groove formed in the holding member for a variator lens, so that the variator lens is also moved parallel to the optical axis by the driving disk. The cam groove on the variator lens holding member is formed to permit movement of the compensator lens independently of the variator lens.
Description
1 3 1 275~ 7217/27460 BA~K~7ROUND OF TH~ INVENTION
Field of the Invention This invention relates generally to a lens moving apparatus wherein two lenses are individually moved with a a certain mutual relationship parallel to the optical axis to effect zooming and, more particularly, to such lens moving apparatus that includes a small-size zoom lens unit suitable for use with a video camera.
Description of the Background A conventional zoom lens unit for use with a video camera normally includes a so-called variator lens and a compensator lens both disposed between a focus lens and a so-called master lens. The variator lens and the compensator lens are mounted for individual movement with a desired mutual relationship parallel to the optical axis to effect a zooming operation. In such conventional apparatus, the individual movements of the variator lens and the compensator lens for such zooming operation are provided by a helicoid gear incorporated in a cylindrical lens holder.
In the conventional arrangement, the helicoid gear necessarily has a diameter substantially equal to the diameter of the focus lens. ~ccordingly, it is a drawback that the conventional zoom lens unit has a comparatively large size due to the required presence of the helicoid gear, even though the individual variator lens and the compensator lens are of comparatively smaller size.
1 3 I 2758 7217/27~60 Furthermore, where a power zoom system is employed, it is necessarv to mount the ~oom drive motor on the outside of the power zoom systeml which also results in the entire lens unit having a very large size.
One arrangement which attempts to eliminate such drawbacks is described in U.S. patent No. 4,853,827. In the optical lens moving mechanism disclosed in that patent, a plane cam is mounted for pivotal motion in a plane parallel to the optical axis of the lens system, and first and second lens groups are individually moved parallel to the optical axis by means of two cam grooves formed in the plane çam.
In order to increase the stroke or length of movement of the first lens group in the optical system of that patent, the size of the plane cam must be increased, which hinders the efforts in reducing the size of the entire arrangement.
Furthermore, because the two cam grooves are provided on the common plane cam, steps must be taken to prevent any interference between the two cams. Accordingly, one drawback of that disclosed arrangement is that the degree of freedom in designing the lens system is diminished when it is required to have two cams on the same flat surface o~ the plane cam.
Another drawback of known lens systems of this type is that it is very difficult to realize a structure to enable movement of only one of the lens groups, while maintaining the other in a stationary condition, in order to effect macro photography.
1 3 1 27 5 8 7~17/27~60 OBJECTS_AND SUMMARY OF TF.IE INVENTION
Accordingly, it is an object of the present invention to provide a lens moving apparatus that can eliminate the deects inherent in the prior art.
Another ob~ect of the present invention is to provide a lens moving apparatus wherein a zoom lens unit i5 made compact, and a variator lens and a compensator lens can make independent desired movements for enabling macro photographic operations.
In accordance with an aspect of the present invention, there is provided a lens moving apparatus that comprises a driving or cam disk mounted on a frame of the lens system for rotation in a plane parallel to the optical axis of the lens s~stem. A cam groove and an engaging pin are provided on a top surface of the driving disk, a first lens holder is supported for movement along the frame parallel with the optical axis, and a cam follower is provided thereon for engaging the cam groove on the driving disk. A second lens holder is also supported for movement along the frame parallel with the opt~cal axis and a guide is provided thereon for engagement with th~ engaging pin formed on the driving disk.
With the lens moving apparatus of the present invention, only the cam groove for moving the first lens holder, that is, for moving the so-called ,-ompensator lens, is provided on the cam disk, so that one cam groove can not interfere with another cam used for driving the second lens 1 31 2758 72l7/27460 holder. The sin~le cam on the cam disk can take forms differerlt than a groove. Accordingly, the two lenses that are associated with the first second lens holders can make individual and independent movements as required.
Furthermore, the first lens holder, on which a compensator lens may be mounted, can be moved without moving the second lens holder, on which a variator lens may be mounted, thereby enabling the lens system to be used in a macro operation for close-up photography. In addition, the driving torque for the cam disk can be reduced and, consequently, further miniaturization of the lens driving system can be attained.
The above and other objects, features, and advantages of the present invention will become apparent from the following detailed description of illustrative embodiments that are to be read in con~unction with the accompanying drawings~ in which like reference numerals represent the same or similar elements.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a p~rspective view of a portion of a zoom mechanism in the optical system of a ~ideo camera accoraing to the present invention;
FigO ~ is a cross-sectional view of the entire optical system of the video camera;
Fig. 3 is a bottom plan view showing a driving system of a zoom mechanism in the optical system of Fig~ 2;
1 31 275~ 72~7/27460 Fig. 4 is a front elevational view of the optical system of Fig. 2;
Fig. 5 is a rear elevational view of the optical system of Fig. 2;
Fig~ 6 is a bottom plan view of the optical system of Fig. 2 performing a wide-angle operation;
Fig. 7 is a side elevational sectional view of the optical system of Fig. 6;
Fig. 8 is a bottom plan vlew of the optical system of Fig. 2 performing a telP-angle operation;
Fig. 9 is a side elevational view in partial cross-section of the optical system of Fig. 8;
Fig. 10 is a bottom plan view of the optical system of Fig. 2 performing macro operation; and Fig. 11 is a side elevational view in partial cross-section of the optical system of Fig. 10.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Initially, Figs. 2 and 3 represent an optical system of a video camera that includes a focus lens 10 that is provided at a forward end of the system and that is supported on a holding member 11. Focus lens holding member 11 is supported on a frame 14 by means of a pair of guide rods 12 and 13. A threaded portion 15 is formed on the inner end of guide rod 12, and the threaded portion is maintained in threaded engagement with a tapped sleeve lÇ
that is adjacent the frame. A pulley 17 is fitted onto 1 3 1 2 7 5 ~ 7217/27460 the outer surface of sleeve 16 and is coupled b~ a belt (not shown) with a focus motor (not shown) mounted on frame 1 near pulley 17. In this manner pulley 17 may be driven ~
the focus motor to move focus lens 10 by action o threaded portion 15 acting like a leacl screw.
A variator lens 20 and a compensator lens 21 are disposed on frame 14 at the rear of locus lens 10. Lenses 20 and 21 are firmly mounted on a pair of holding members 22 and 23, respectivel~. Holding members 22 and 23 are supported by means of three guide rods 24, 25, and 26 shown clearly in Fig.l.
Referring then to Fig. 1, holding member 22, on which variator lens 20 is mounted, is supported by means of guide rods 24 and 26, whereas holding member 23, on which compensator lens 21 is mounted, is supported by means of guide rods 25 and 26.
Now, a mechanism for moving holding members 22 and 23 on which lenses 20 and 21 ar~ mounted, respectivelyr will be described with reference to Figs. 1, 2, and 3. The lens moving mechanism includes a driving or cam disk 30 supported for rotation on frame 14. A pin 31 is arranged on cam disk 30 for engagement with a cam groove 32 formed on a lower face of holding member 22 on which variator lens 20 is mounted. The upper end of cam groove 32 terminates in an actuate guide face 33, as shown in Fig. 3. A cam follower pin 34 is provided on a lower face of holding member 23 on which compensator lens 21 is mounted, and cam ollower pin 34 normally engages with a cam groove 35 formed on cam disk 30.
1 3 1 2 7 5 8 721~/274~0 A motor 36 i.s moun~ed on one side of frame 14 and a pulley 37, partially hidden in Fig. 2, is secu.red to an output power shaft (not shown) of motor 36 and is coupled to a pulley 38 by means of a be:Lt 39. A worm 40 is mounte~ on pulley 38 and is held in meshing engagement with a worm wheel 41. A driving gear 42 is mounted on worm wheel 41 and is held in meshing engagement with the teeth of a gear ~3 formed on the outer periphery of cam disk 30.
An iris unit 45, the elements of which are not shown, is disposed at the rear of compensator lens 21. A
cylindrical lens holder ~6 is mounted on frame 14 at the rear of iris unit 45, and a master lens set, shown generall~
at 47, includes a plurality of lenses and is mounted in cylindrical lens holder 46. A frame 48 is securel~ mounted at the rear end of cylindrical lens holder 46, and a charge coupled device (CCD~ imager 49 is mounted on frame 48. The relationship among cylindrical lens holder 46, frame 48, and imager 49 is shown in Fig. 5.
In the operation, particularly a zooming operation, of the lens moving apparatus as described above, ~or wide-angle operation to widen the angle of view cam disk 30 is rotated counterclockwisel relative to Fig. 6, by motor 36 by way of pulle~ 37, belt 39, pulley 38, worm 40, worm wheel 41, driving gear 42, and gear 43. Thereupon, holding member 22 i5 pushed along cam groove 32 by pin 31 on cam disk 30 to move variator lens 20 toward focus lens 10.
Simultaneouslv, compensator lens 21 is moved toward CCD
imager 49 by cam grove 35 of cam disk 30 by way of cam follower 34 affixed to holding member 23. In summary, upon wide~angle operation, variator lens 20 and compensator lens 21 are moved away from each other.
For tele-angle ope:ration to narrow the angle of view, cam disk 30 is rotated in the clockwise direction, relative to Fig. 8, so that holding member 22 is moved rearwardly by pin 31 cooperating with cam groove 35 on disk 30 to move variator lens 20 back to a position directly in front of the compensator lens 21, as shown in Figs. 8 and 9.
In summary, variator lens 20 and compensator lens 21 are both moved away from the locus lens 10 while narrowing the field of view, as in so-called tele-angle operation, In a macro operation for close-up photography, with reference to Figs. 10 and 11, cam disk 30 is rotated farther in the counterclockwise direction than the most wide-angle position thereof. ~hereupon, pin 31 on cam disk 30 is disengaged from cam groove 32 of holding member 22 and is brought into engagement with arcuate guide face 33 that is contiguous to cam groove 32. It should be noted that in this case variator lens 20 is not moved paral~el to the optical axis, because here the arcuate guide face 33 has a profile which coincides with a locus of the turning movement of pin 31. While variator lens 20 remains stationary, holding member 23, on which compensator len~ 21 is mounted, is advanced a short distance toward focus lens 20 b~ an end portion of cam groove 35 on cam disk 30. In this manner, only compensator lens 21 is moved, while variator lens 20 remains in a stationary condition, thereby enabling a macro operation of the optical system for close-up photography, that is, close-up video pictures with a video camera.
With the lens movi:ng apparatus describea above, it is possible to move compensator lens 21 directly hy cam groove 35 formed in cam disk 30 and, also, to move variator lens 20 along a path parallel to the optical axis through engagement of pin 31 mounted on cam disk 30 with cam groove 32 formed in holding member 22, as described hereinabove.
Holding members 22 and 23 for the two lenses 20 and 21, respectively, are guided for movement parallel to the optical axis by three guide rods 24 to 26. ~ccordingly, the æoom lens unit does not require a cylindrical lens holder, and it is possible to place the driving system, such as disk driving motor 36, in the space that is provided by the elimination of such a cylindrical lens holder. As a result, miniaturization of the optical system of the video camera, particularly the æoom lens unit thereof, is enabled.
Holding member 11 for focus lens 10 is guided by two guide rods 12 and 13, and focus lens 10 is moved parallel to the optical axis by threaded portion 15 of guide rod 12 to effect focusing of the optical system. Because the driving mechanism for focus lens 10 is also disposed in the surplus spacing around the outer periphery of the zoom lens unit, no component of the driving system will extend outwardly beyond the outer peripher~ of focus lens 10.
1 3 1 2 7 5 ~ 7~17/27460 Furthermore, as shown in Fig. ~, the upper and lower end portions of focus lens 10 are cut off in order to reduce the vertical dimension of the locus lens 10. Because mounting of focus lens 10 is attained not by means of a ring nut or threaded ring but by means of fastening screws 5~
mounted at four corners of holding member 11, as shown in Fig. 4, it is possible to assure a comparatively large opening for focus lens 10. Bv the combination of these structures it is possible to accommodate all of the mechanism, even including the electric driving system, within a space not greater than the outer diameter of focus lens 10, which has the upper and lower portions thereof cut off as described above, and consequently to make the entire lens arrangement compact.
In the structure according to the present embodiment, variator lens 20 is moved as holding member 22 is driven by cam groove 32 cooperating with pin 31.
Accordingly, even if cam disk 30 is rotated to a position in which a radial line passing through pin 31 extends parallel to the optical axis, a high load will not be applied to cam disk 30. If the variator lens is moved by a cam groove that is also formed on the disk in addition to the cam groove provided for the compensator lens, a high lateral pressure will be applied to the cam depending upon the rotational position of the disk, caused in part ~y the binding due to intersection of moving two separate elements. This high lateral pressure means that a very high driving toraue will ~10--1 3 1 2 7 5 ~ 7217/27~6n be re~uired to rotate the cam disk. On the contrary, with the apparatus according to the present embodiment such high lateral pressures are eliminated, and it is possible to rotate cam disk 30 wikh a lower torque, so as to move the two lenses 20 and 21 smoothly in the direction of the optical axis to effect an accurate zooming operation.
In this embodiment the cam on the cam disk is formed as a groove and the cam follower is a pin, however, the invention is equally applicable to other forms of cams and cam followers.
The above description is given on a single preferred embodiment of the invention, but it will be apparent that many modifications ancl variations could be effected by one skilled in the art without departing from the spirit or scope of the novel concepts of the invention, which should be determined by the appended claims.
Field of the Invention This invention relates generally to a lens moving apparatus wherein two lenses are individually moved with a a certain mutual relationship parallel to the optical axis to effect zooming and, more particularly, to such lens moving apparatus that includes a small-size zoom lens unit suitable for use with a video camera.
Description of the Background A conventional zoom lens unit for use with a video camera normally includes a so-called variator lens and a compensator lens both disposed between a focus lens and a so-called master lens. The variator lens and the compensator lens are mounted for individual movement with a desired mutual relationship parallel to the optical axis to effect a zooming operation. In such conventional apparatus, the individual movements of the variator lens and the compensator lens for such zooming operation are provided by a helicoid gear incorporated in a cylindrical lens holder.
In the conventional arrangement, the helicoid gear necessarily has a diameter substantially equal to the diameter of the focus lens. ~ccordingly, it is a drawback that the conventional zoom lens unit has a comparatively large size due to the required presence of the helicoid gear, even though the individual variator lens and the compensator lens are of comparatively smaller size.
1 3 I 2758 7217/27~60 Furthermore, where a power zoom system is employed, it is necessarv to mount the ~oom drive motor on the outside of the power zoom systeml which also results in the entire lens unit having a very large size.
One arrangement which attempts to eliminate such drawbacks is described in U.S. patent No. 4,853,827. In the optical lens moving mechanism disclosed in that patent, a plane cam is mounted for pivotal motion in a plane parallel to the optical axis of the lens system, and first and second lens groups are individually moved parallel to the optical axis by means of two cam grooves formed in the plane çam.
In order to increase the stroke or length of movement of the first lens group in the optical system of that patent, the size of the plane cam must be increased, which hinders the efforts in reducing the size of the entire arrangement.
Furthermore, because the two cam grooves are provided on the common plane cam, steps must be taken to prevent any interference between the two cams. Accordingly, one drawback of that disclosed arrangement is that the degree of freedom in designing the lens system is diminished when it is required to have two cams on the same flat surface o~ the plane cam.
Another drawback of known lens systems of this type is that it is very difficult to realize a structure to enable movement of only one of the lens groups, while maintaining the other in a stationary condition, in order to effect macro photography.
1 3 1 27 5 8 7~17/27~60 OBJECTS_AND SUMMARY OF TF.IE INVENTION
Accordingly, it is an object of the present invention to provide a lens moving apparatus that can eliminate the deects inherent in the prior art.
Another ob~ect of the present invention is to provide a lens moving apparatus wherein a zoom lens unit i5 made compact, and a variator lens and a compensator lens can make independent desired movements for enabling macro photographic operations.
In accordance with an aspect of the present invention, there is provided a lens moving apparatus that comprises a driving or cam disk mounted on a frame of the lens system for rotation in a plane parallel to the optical axis of the lens s~stem. A cam groove and an engaging pin are provided on a top surface of the driving disk, a first lens holder is supported for movement along the frame parallel with the optical axis, and a cam follower is provided thereon for engaging the cam groove on the driving disk. A second lens holder is also supported for movement along the frame parallel with the opt~cal axis and a guide is provided thereon for engagement with th~ engaging pin formed on the driving disk.
With the lens moving apparatus of the present invention, only the cam groove for moving the first lens holder, that is, for moving the so-called ,-ompensator lens, is provided on the cam disk, so that one cam groove can not interfere with another cam used for driving the second lens 1 31 2758 72l7/27460 holder. The sin~le cam on the cam disk can take forms differerlt than a groove. Accordingly, the two lenses that are associated with the first second lens holders can make individual and independent movements as required.
Furthermore, the first lens holder, on which a compensator lens may be mounted, can be moved without moving the second lens holder, on which a variator lens may be mounted, thereby enabling the lens system to be used in a macro operation for close-up photography. In addition, the driving torque for the cam disk can be reduced and, consequently, further miniaturization of the lens driving system can be attained.
The above and other objects, features, and advantages of the present invention will become apparent from the following detailed description of illustrative embodiments that are to be read in con~unction with the accompanying drawings~ in which like reference numerals represent the same or similar elements.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a p~rspective view of a portion of a zoom mechanism in the optical system of a ~ideo camera accoraing to the present invention;
FigO ~ is a cross-sectional view of the entire optical system of the video camera;
Fig. 3 is a bottom plan view showing a driving system of a zoom mechanism in the optical system of Fig~ 2;
1 31 275~ 72~7/27460 Fig. 4 is a front elevational view of the optical system of Fig. 2;
Fig. 5 is a rear elevational view of the optical system of Fig. 2;
Fig~ 6 is a bottom plan view of the optical system of Fig. 2 performing a wide-angle operation;
Fig. 7 is a side elevational sectional view of the optical system of Fig. 6;
Fig. 8 is a bottom plan vlew of the optical system of Fig. 2 performing a telP-angle operation;
Fig. 9 is a side elevational view in partial cross-section of the optical system of Fig. 8;
Fig. 10 is a bottom plan view of the optical system of Fig. 2 performing macro operation; and Fig. 11 is a side elevational view in partial cross-section of the optical system of Fig. 10.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Initially, Figs. 2 and 3 represent an optical system of a video camera that includes a focus lens 10 that is provided at a forward end of the system and that is supported on a holding member 11. Focus lens holding member 11 is supported on a frame 14 by means of a pair of guide rods 12 and 13. A threaded portion 15 is formed on the inner end of guide rod 12, and the threaded portion is maintained in threaded engagement with a tapped sleeve lÇ
that is adjacent the frame. A pulley 17 is fitted onto 1 3 1 2 7 5 ~ 7217/27460 the outer surface of sleeve 16 and is coupled b~ a belt (not shown) with a focus motor (not shown) mounted on frame 1 near pulley 17. In this manner pulley 17 may be driven ~
the focus motor to move focus lens 10 by action o threaded portion 15 acting like a leacl screw.
A variator lens 20 and a compensator lens 21 are disposed on frame 14 at the rear of locus lens 10. Lenses 20 and 21 are firmly mounted on a pair of holding members 22 and 23, respectivel~. Holding members 22 and 23 are supported by means of three guide rods 24, 25, and 26 shown clearly in Fig.l.
Referring then to Fig. 1, holding member 22, on which variator lens 20 is mounted, is supported by means of guide rods 24 and 26, whereas holding member 23, on which compensator lens 21 is mounted, is supported by means of guide rods 25 and 26.
Now, a mechanism for moving holding members 22 and 23 on which lenses 20 and 21 ar~ mounted, respectivelyr will be described with reference to Figs. 1, 2, and 3. The lens moving mechanism includes a driving or cam disk 30 supported for rotation on frame 14. A pin 31 is arranged on cam disk 30 for engagement with a cam groove 32 formed on a lower face of holding member 22 on which variator lens 20 is mounted. The upper end of cam groove 32 terminates in an actuate guide face 33, as shown in Fig. 3. A cam follower pin 34 is provided on a lower face of holding member 23 on which compensator lens 21 is mounted, and cam ollower pin 34 normally engages with a cam groove 35 formed on cam disk 30.
1 3 1 2 7 5 8 721~/274~0 A motor 36 i.s moun~ed on one side of frame 14 and a pulley 37, partially hidden in Fig. 2, is secu.red to an output power shaft (not shown) of motor 36 and is coupled to a pulley 38 by means of a be:Lt 39. A worm 40 is mounte~ on pulley 38 and is held in meshing engagement with a worm wheel 41. A driving gear 42 is mounted on worm wheel 41 and is held in meshing engagement with the teeth of a gear ~3 formed on the outer periphery of cam disk 30.
An iris unit 45, the elements of which are not shown, is disposed at the rear of compensator lens 21. A
cylindrical lens holder ~6 is mounted on frame 14 at the rear of iris unit 45, and a master lens set, shown generall~
at 47, includes a plurality of lenses and is mounted in cylindrical lens holder 46. A frame 48 is securel~ mounted at the rear end of cylindrical lens holder 46, and a charge coupled device (CCD~ imager 49 is mounted on frame 48. The relationship among cylindrical lens holder 46, frame 48, and imager 49 is shown in Fig. 5.
In the operation, particularly a zooming operation, of the lens moving apparatus as described above, ~or wide-angle operation to widen the angle of view cam disk 30 is rotated counterclockwisel relative to Fig. 6, by motor 36 by way of pulle~ 37, belt 39, pulley 38, worm 40, worm wheel 41, driving gear 42, and gear 43. Thereupon, holding member 22 i5 pushed along cam groove 32 by pin 31 on cam disk 30 to move variator lens 20 toward focus lens 10.
Simultaneouslv, compensator lens 21 is moved toward CCD
imager 49 by cam grove 35 of cam disk 30 by way of cam follower 34 affixed to holding member 23. In summary, upon wide~angle operation, variator lens 20 and compensator lens 21 are moved away from each other.
For tele-angle ope:ration to narrow the angle of view, cam disk 30 is rotated in the clockwise direction, relative to Fig. 8, so that holding member 22 is moved rearwardly by pin 31 cooperating with cam groove 35 on disk 30 to move variator lens 20 back to a position directly in front of the compensator lens 21, as shown in Figs. 8 and 9.
In summary, variator lens 20 and compensator lens 21 are both moved away from the locus lens 10 while narrowing the field of view, as in so-called tele-angle operation, In a macro operation for close-up photography, with reference to Figs. 10 and 11, cam disk 30 is rotated farther in the counterclockwise direction than the most wide-angle position thereof. ~hereupon, pin 31 on cam disk 30 is disengaged from cam groove 32 of holding member 22 and is brought into engagement with arcuate guide face 33 that is contiguous to cam groove 32. It should be noted that in this case variator lens 20 is not moved paral~el to the optical axis, because here the arcuate guide face 33 has a profile which coincides with a locus of the turning movement of pin 31. While variator lens 20 remains stationary, holding member 23, on which compensator len~ 21 is mounted, is advanced a short distance toward focus lens 20 b~ an end portion of cam groove 35 on cam disk 30. In this manner, only compensator lens 21 is moved, while variator lens 20 remains in a stationary condition, thereby enabling a macro operation of the optical system for close-up photography, that is, close-up video pictures with a video camera.
With the lens movi:ng apparatus describea above, it is possible to move compensator lens 21 directly hy cam groove 35 formed in cam disk 30 and, also, to move variator lens 20 along a path parallel to the optical axis through engagement of pin 31 mounted on cam disk 30 with cam groove 32 formed in holding member 22, as described hereinabove.
Holding members 22 and 23 for the two lenses 20 and 21, respectively, are guided for movement parallel to the optical axis by three guide rods 24 to 26. ~ccordingly, the æoom lens unit does not require a cylindrical lens holder, and it is possible to place the driving system, such as disk driving motor 36, in the space that is provided by the elimination of such a cylindrical lens holder. As a result, miniaturization of the optical system of the video camera, particularly the æoom lens unit thereof, is enabled.
Holding member 11 for focus lens 10 is guided by two guide rods 12 and 13, and focus lens 10 is moved parallel to the optical axis by threaded portion 15 of guide rod 12 to effect focusing of the optical system. Because the driving mechanism for focus lens 10 is also disposed in the surplus spacing around the outer periphery of the zoom lens unit, no component of the driving system will extend outwardly beyond the outer peripher~ of focus lens 10.
1 3 1 2 7 5 ~ 7~17/27460 Furthermore, as shown in Fig. ~, the upper and lower end portions of focus lens 10 are cut off in order to reduce the vertical dimension of the locus lens 10. Because mounting of focus lens 10 is attained not by means of a ring nut or threaded ring but by means of fastening screws 5~
mounted at four corners of holding member 11, as shown in Fig. 4, it is possible to assure a comparatively large opening for focus lens 10. Bv the combination of these structures it is possible to accommodate all of the mechanism, even including the electric driving system, within a space not greater than the outer diameter of focus lens 10, which has the upper and lower portions thereof cut off as described above, and consequently to make the entire lens arrangement compact.
In the structure according to the present embodiment, variator lens 20 is moved as holding member 22 is driven by cam groove 32 cooperating with pin 31.
Accordingly, even if cam disk 30 is rotated to a position in which a radial line passing through pin 31 extends parallel to the optical axis, a high load will not be applied to cam disk 30. If the variator lens is moved by a cam groove that is also formed on the disk in addition to the cam groove provided for the compensator lens, a high lateral pressure will be applied to the cam depending upon the rotational position of the disk, caused in part ~y the binding due to intersection of moving two separate elements. This high lateral pressure means that a very high driving toraue will ~10--1 3 1 2 7 5 ~ 7217/27~6n be re~uired to rotate the cam disk. On the contrary, with the apparatus according to the present embodiment such high lateral pressures are eliminated, and it is possible to rotate cam disk 30 wikh a lower torque, so as to move the two lenses 20 and 21 smoothly in the direction of the optical axis to effect an accurate zooming operation.
In this embodiment the cam on the cam disk is formed as a groove and the cam follower is a pin, however, the invention is equally applicable to other forms of cams and cam followers.
The above description is given on a single preferred embodiment of the invention, but it will be apparent that many modifications ancl variations could be effected by one skilled in the art without departing from the spirit or scope of the novel concepts of the invention, which should be determined by the appended claims.
Claims (14)
1. Apparatus for moving lenses in a lens system having a plurality of lenses, comprising:
a frame;
a cam disk mounted on said frame for rotation in a plane parallel to an optical axis of said plurality of lenses;
a cam groove and an upstanding engagement pin arranged on a flat surface of said cam disk;
a first lens holder mounted for slidable movement parallel to said optical axis and having a cam follower for engagement with said cam groove on said cam disk; and a second lens holder mounted for slidable movement parallel to said optical axis and having a guide groove for engagement with said upstanding engagement pin on said driving disk, whereby upon rotation of said cam disk said first and second lens holders are slidably moved.
a frame;
a cam disk mounted on said frame for rotation in a plane parallel to an optical axis of said plurality of lenses;
a cam groove and an upstanding engagement pin arranged on a flat surface of said cam disk;
a first lens holder mounted for slidable movement parallel to said optical axis and having a cam follower for engagement with said cam groove on said cam disk; and a second lens holder mounted for slidable movement parallel to said optical axis and having a guide groove for engagement with said upstanding engagement pin on said driving disk, whereby upon rotation of said cam disk said first and second lens holders are slidably moved.
2. Apparatus for moving lenses according to claim 1, wherein said first lens holder supports a compensator lens thereon and said second lens holder supports a variator lens thereon, and further comprising a motor and gear teeth formed on the periphery of said cam disk, whereby said cam disk is coupled with said motor for rotating said cam disk during a zooming operation.
3. Apparatus for moving lenses according to claim 2, wherein said cam groove provided on said cam disk has a zooming operation portion and a macro operation portion provided adjacent each other and wherein said guide groove provided on said second lens holder has a zooming operation portion and a macro operation portion provided adjacent each other.
4. Apparatus for moving lenses according to claim 3, wherein said macro operation portion of said guide groove has an arcuate shape substantially equal to a locus of said engagement pin during rotation of said cam disk when said cam follower engages said macrooperation portion of said cam groove, so that said first lens holder is slidably moved by rotation of said cam disk and said second lens holder remains stationary.
5. Apparatus for moving lenses according to claim 2, further comprising a third lens holder provided in front of said first lens holder and said second lens holder along said optical axis for carrying a focus lens thereon and a fourth lens holder provided in the rear of said first and second lens holders along said optical axis for carrying a master lens thereon.
6. Apparatus for moving lenses as recited in claim 5, wherein said focus lens has a substantially rectangular shape and said third lens holder is supported on a plurality of supporting rods that extend through a front wall of said frame.
7. Apparatus for moving lenses according to claim 2, further comprising guide rods having ends thereof selectively fixed and slidably mounted to said first and second lens holder and to said frame so that during said slidable movement said first and second lens holders are aligned with said optical axis.
8. Lens moving apparatus for a lens system having a plurality of lenses, comprising:
a frame;
a cam disk mounted on said frame for rotation in a plane parallel to an optical axis of said plurality of lenses;
a cam and an upraised pin provided on a flat surface of said cam disk;
a first lens holder supported for sliding movement on said frame parallel to said optical axis and having a cam follower for engagement with said cam on said cam disk; and a second lens holder supported for sliding movement on said frame parallel to said optical axis and having a guide groove provided thereon for engagement with said upraised pin on said driving disk, whereby rotation of said cam disk imparts said sliding movement.
a frame;
a cam disk mounted on said frame for rotation in a plane parallel to an optical axis of said plurality of lenses;
a cam and an upraised pin provided on a flat surface of said cam disk;
a first lens holder supported for sliding movement on said frame parallel to said optical axis and having a cam follower for engagement with said cam on said cam disk; and a second lens holder supported for sliding movement on said frame parallel to said optical axis and having a guide groove provided thereon for engagement with said upraised pin on said driving disk, whereby rotation of said cam disk imparts said sliding movement.
9. Lens moving apparatus according to claim 8, further comprising a motor and wherein said first lens holder supports a compensator lens thereon and said second lens holder supports a variator lens thereon, and said cam disk includes gear teeth formed on the periphery thereof to be coupled with said motor for rotating said cam disk during a zooming operation.
10. Apparatus for moving lenses according to claim 9, wherein said cam provided on said cam disk has a zooming operation segment and an adjacent macro operation segment and said guide groove provided on said second lens holder has a zooming operation segment and an adjacent macro operation segment.
11. Lens moving apparatus according to claim 10, wherein said macro operation segment of said guide groove is arcuately shaped with a curvature equal to a locus of said upraised pin during rotation of said cam disk when said cam follower engages said macro operation segment of said cam, so that said compensator lens moves and said variator lens remains stationary during rotation of said cam disk.
12. Lens moving apparatus according to claim 10, further comprising a plurality of guide rods fixed to said frame for slidably supporting said first and second lens holders.
13. Lens moving apparatus according to claim 10, further comprising a third lens holder provided adjacent said first lens holder on a side opposite said second lens holder for carrying a focus lens thereon, and a fourth lens holder provided adjacent said second lens holder on a side opposite said second lens holder for carrying a master lens thereon.
14. Lens moving apparatus according to claim 13, wherein said locus lens has a substantially rectangular shape and said third lens holder is supported on a plurality of supporting rods extending through a front wall of said frame.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP118518/87 | 1987-05-15 | ||
| JP62118518A JP2832930B2 (en) | 1987-05-15 | 1987-05-15 | Lens moving device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1312758C true CA1312758C (en) | 1993-01-19 |
Family
ID=14738607
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000566619A Expired - Fee Related CA1312758C (en) | 1987-05-15 | 1988-05-12 | Lens driving apparatus |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JP2832930B2 (en) |
| KR (1) | KR880014804A (en) |
| CA (1) | CA1312758C (en) |
| DE (1) | DE3816482A1 (en) |
| GB (1) | GB2204712A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH03253826A (en) * | 1990-03-05 | 1991-11-12 | Asahi Optical Co Ltd | Automatic photographing device for camera |
| JP2004191657A (en) * | 2002-12-11 | 2004-07-08 | Sony Corp | Camera device |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5039522Y2 (en) * | 1972-05-12 | 1975-11-13 | ||
| AT343937B (en) * | 1975-08-06 | 1978-06-26 | Eumig | PANRATIC LENS |
| US4583827A (en) * | 1982-12-07 | 1986-04-22 | Matsushita Electric Industrial Co., Ltd. | Optical lens moving mechanism |
-
1987
- 1987-05-15 JP JP62118518A patent/JP2832930B2/en not_active Expired - Fee Related
-
1988
- 1988-04-15 GB GB08808895A patent/GB2204712A/en not_active Withdrawn
- 1988-05-12 CA CA000566619A patent/CA1312758C/en not_active Expired - Fee Related
- 1988-05-13 KR KR1019880005554A patent/KR880014804A/en not_active Application Discontinuation
- 1988-05-13 DE DE3816482A patent/DE3816482A1/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| GB8808895D0 (en) | 1988-05-18 |
| DE3816482A1 (en) | 1988-12-01 |
| JP2832930B2 (en) | 1998-12-09 |
| KR880014804A (en) | 1988-12-24 |
| GB2204712A (en) | 1988-11-16 |
| JPS63282712A (en) | 1988-11-18 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed |