JP2012133114A - Imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging device capable of shortening a time required for reset operation and outputting a focused image at the time when the reset operation is completed.SOLUTION: Provided are a zoom stepping motor for driving a zoom lens in an optical axis direction in a displacing manner, a focus stepping motor for driving a focus lens in the optical axis direction in a displacing manner, a zoom reset switch for setting an initial reset position of the zoom stepping motor, and a focus reset switch for setting an initial reset position of the focus stepping motor. Initial reset positions R of the zoom stepping motor and the focus stepping motor are set at positions that coincide with an inflection point of a zoom tracking curve S showing a relative positional relation at the time of focusing with the zoom lens and the focus lens.

Description

  The present invention relates to an imaging apparatus.

  In recent years, an image of a subject formed by a plurality of lenses is received by an image sensor such as a charge coupled device (CCD) or a complementary metal-oxide semiconductor (CMOS) sensor, and the light received by the image sensor is photoelectrically converted. Imaging devices such as digital video cameras, digital still cameras, and surveillance cameras that are output as electrical signals and generate and record digital images corresponding to the image of the subject have become widespread.

  In such an imaging device, among a plurality of lenses arranged in the lens barrel, zooming (zooming) while moving the zoom (variator) lens in the optical axis direction, and moving the focusing lens in the optical axis direction Focusing while doing.

  Further, in the conventional imaging apparatus, a stepping motor is employed as a drive motor that drives the zoom lens in the optical axis direction and a drive motor that drives the focus lens in the optical axis direction, and pulses supplied to these stepping motors The movement amount (position) of the lens is controlled while counting the number (see, for example, Patent Documents 1 and 2).

  In general, when a stepping motor is used, since it is an open loop control, a reset operation is required to set the initial reset position of the stepping motor when the power is turned on (ON).

  In other words, when such a reset operation is not performed, the positional relationship between the zoom lens and the focus lens becomes unclear at the moment when zooming is performed, even when autofocus is in focus. The focus is out of focus.

  Here, FIG. 7 shows a zoom tracking curve (cam curve) S indicating the relative positional relationship between the zoom lens and the focus lens at the time of focusing. In the graph shown in FIG. 7, the horizontal axis indicates the position from the wide-angle (Wide) end to the telephoto (Tele) end of the zoom lens, and the vertical axis indicates the position from the closest end point to the infinite end point of the focusing lens. The tracking curve S represents the position at which the focus lens is in focus when the zoom lens is zoomed between the wide-angle (wide) end and the telephoto (tele) end.

  Since the in-focus state is maintained on the line of the zoom tracking curve S in the image pickup apparatus, the position information of the zoom lens and the focus lens driven by the zooming and focusing stepping motors described above is used as this positional information. The zoom tracking curve S is stored in advance in the stepping motor control circuit.

  On the other hand, when controlling the driving of the stepping motor, in order to accurately trace the stored zoom tracking curve S, the positions of the zoom lens and the focus lens (initial reset position) are checked every time the power is turned on. For this, an initial operation (reset operation) is required.

  In the imaging apparatus, after the positions of the zoom lens and the focus lens are confirmed by the reset operation, the stepping motor drives the zoom lens and the focus lens based on the zoom tracking curve S described above. Thus, it is possible to perform the zooming operation while maintaining the focused state.

  In order to perform such a reset operation, the imaging apparatus includes a zoom reset switch that sets an initial reset position of the zoom stepping motor and a focus reset switch that sets an initial reset position of the focus stepping motor. ing.

  In the conventional imaging apparatus, in the graph shown in FIG. 7, the initial reset position of the zoom stepping motor is located in the middle of the movable range of the zoom lens, and the initial reset position of the focus stepping motor is movable of the focus lens. The initial reset position R by the reset switch described above is set so as to be located in the middle of the range.

  In this case, the zoom lens and the focus lens can be moved to the initial reset position R in a minimum time regardless of the position at the time of the previous power shutdown (OFF). Further, the reset operation of the zoom stepping motor and the reset operation of the focus stepping motor are simultaneously performed, thereby reducing the time required for the reset operation.

JP 2006-162675 A JP 2006-122583 A

  However, in the conventional imaging apparatus described above, since the initial reset position R does not exist on the zoom tracking curve S, the focused state is not achieved when the reset operation is completed. For this reason, in the conventional imaging apparatus, after the reset operation is completed, a focusing operation for positioning the zoom lens and the focusing lens on the zoom tracking curve S is necessary. Note that Z shown in FIG. 7 represents the amount of movement of the focusing lens necessary for the focusing operation.

  Therefore, in the conventional imaging apparatus, it takes a lot of time from when the power is turned on until the reset operation is completed and an in-focus image is output by the focusing operation. In addition, an in-focus image cannot be output immediately after the power is turned on.

  On the other hand, in the graph shown in FIG. 7, when the initial reset position R ′ is positioned on the zoom tracking curve S, the focused state is maintained when the reset operation is completed by design. It is possible to output a matched image.

  However, there are individual differences in the lenses, and the focal length of each lens group slightly deviates from its design value due to the design error of each lens and its stacking. In addition, due to variations in the mounting position of the image sensor, the focus position of the zoom lens deviates from the design value. As a result, the zoom tracking curve of the zoom lens has a deviation from the design value.

  For this reason, an error X of about ± 0.2 mm may actually occur in the mounting position of the reset switch. In this case, the initial reset position R ′ has a large positional deviation Y ′ from the zoom tracking curve S, so that a minute blur occurs in the image output when the reset operation is completed. Therefore, also in this case, after the reset operation is completed, a focusing operation for positioning the zoom lens and the focus lens on the zoom tracking curve S is required.

  The present invention has been proposed in view of such a conventional situation, and an imaging apparatus capable of outputting an in-focus image immediately after the reset operation is completed while reducing the time required for the reset operation. The purpose is to provide.

  In order to achieve the above object, an imaging apparatus according to the present invention includes a plurality of lenses including a zooming lens and a focusing lens, a lens barrel body in which the plurality of lenses are arranged in the optical axis direction, and zooming. Zoom lens holding member that holds the lens for focusing, focus lens holding member that holds the focusing lens, zoom lens driving mechanism that drives the zoom lens holding member to be displaced in the optical axis direction, and focus lens holding member A focus lens drive mechanism for moving the lens in the optical axis direction, a zoom reset switch for setting an initial reset position of the zoom lens drive mechanism, and a focus reset switch for setting an initial reset position of the focus lens drive mechanism The initial reset position of the zoom lens drive mechanism and the focus lens drive mechanism But wherein it is set at a position that matches the inflection point of the zoom tracking curve showing the relative positional relationship at the time of focusing of the zoom lens and the focusing lens.

  As described above, in the imaging apparatus according to the present invention, the initial reset positions of the zoom lens drive mechanism and the focus lens drive mechanism are shown in a relative positional relationship when the zoom lens and the focus lens are in focus. Even if there is a reset switch installation error by setting it to a position that matches the inflection point of the zoom tracking curve, the position shift of the initial reset position from the zoom tracking curve is in focus after the reset operation is completed. It can be reduced to a level that does not require action. Therefore, in this imaging apparatus, it is possible to output an in-focus image immediately after the reset operation is completed while shortening the time required for the reset operation.

FIG. 1 is a perspective view showing an appearance of an imaging apparatus to which the present invention is applied. FIG. 2 is an exploded perspective view showing the configuration of the imaging apparatus shown in FIG. FIG. 3 is a sectional view showing the internal structure of the image pickup apparatus shown in FIG. 1 at the wide end position. 4 is a sectional view showing the internal structure of the imaging apparatus shown in FIG. 1 at the tele end position. FIG. 5 is a sectional view showing the internal structure of the image pickup apparatus shown in FIG. 1 at the initial reset position. FIG. 6 is a graph for explaining the relationship between the initial reset position and the zoom tracking curve of the present invention. FIG. 7 is a graph for explaining the relationship between a conventional initial reset position and a zoom tracking curve.

Hereinafter, an imaging apparatus to which the present invention is applied will be described in detail with reference to the drawings.
1 is a perspective view showing an appearance of an imaging apparatus 1 to which the present invention is applied, FIG. 2 is an exploded perspective view showing a configuration of the imaging apparatus 1 shown in FIG. 1, and FIG. 3 is shown in FIG. 4 is a sectional view showing the internal structure of the imaging device 1 at the wide end position, FIG. 4 is a sectional view showing the internal structure of the imaging device 1 shown in FIG. 1 at the tele end position, and FIG. FIG. 2 is a partial cross-sectional view showing an internal structure at an initial reset position of the imaging apparatus 1 shown in FIG.

  The imaging apparatus 1 to which the present invention is applied includes a mirror in which a plurality (14 in this example) of lenses L1 to L14 are arranged side by side in the optical axis direction, as shown in FIGS. An inner focus type zoom lens is configured by a plurality of lenses L <b> 1 to L <b> 14 that are provided with a barrel main body 2 and are arranged on the barrel main body.

  Specifically, this zoom lens includes, in order from the object side (the front side of the imaging device 1), a first lens group G1 including lenses L1, L2, L3, and L4, and a first lens group including lenses L5, L6, L7, and L8. 2 lens group (zoom (variator) lens) G2, third lens group G3 consisting of lenses L9 and L10, fourth lens group (correction lens) G4 consisting of lenses L11 and L12, and lenses L13 and L14. The fifth lens group (focusing lens) G5 has a five-group lens configuration. An aperture stop SP is disposed between the second lens group G2 and the third lens group G3. The configuration of the zoom lens is not limited to the configuration of the 14 lenses in the 5 groups described above, and the number and combination of the lenses can be changed as appropriate.

  In addition, the imaging apparatus 1 converts the image of the subject formed by the plurality of lenses L1 to L14 (zoom lens) into a CCD (Charge Coupled Device) or CMOS (Complementary) attached to the rear end side of the lens barrel body 2. It is possible to generate a digital image corresponding to a subject image by photoelectrically converting the light received by the imaging element IP such as a metal-oxide semiconductor sensor and photoelectrically converting the light received by the imaging element IP. ing.

  Note that such an imaging apparatus 1 can be applied to, for example, a digital video camera, a digital still camera, a surveillance camera, and the like. The imaging apparatus 1 can record the generated digital image (moving image or still image) on a recording medium such as an HDD (Hard Disk Drive), a memory card, an optical disk, or a magnetic tape.

  The lens barrel body 2 includes a front lens barrel 3, an intermediate lens barrel 4, and a rear lens barrel 5 that are divided into three in the front-rear direction of the optical axis. Between the intermediate lens barrel 4 and the rear lens barrel 5, a diaphragm adjusting mechanism 6 for adjusting the aperture of the diaphragm SP, and a camera shake correcting mechanism 7 for driving the correction lens G4 in a direction perpendicular to the optical axis. Are integrated with each other.

  Among these, the front barrel 3 is positioned and fixed on the front side of the intermediate barrel 4 with the first lens group G1 held inside. Specifically, a plurality of positioning holes 3 a that are positioned with respect to the intermediate lens barrel 4 and screws (not shown) that are screwed to the intermediate lens barrel 4 are provided on the back side of the front lens barrel 3. A plurality of through holes 3b to be penetrated are formed. On the other hand, on the front side of the intermediate lens barrel 4, there are positioning projections 4a with which the plurality of positioning holes 3a are engaged, and a plurality of screw holes 4b with which screws passing through the plurality of through holes 3b are screwed. Is formed.

  The front lens barrel 3 is positioned with respect to the intermediate lens barrel 4 by engaging the positioning projection 4a with the positioning hole 3a, and the screw is screwed into the screw hole 4b through the through hole 3b. Thus, the intermediate lens barrel 4 is fixed to the front side.

  On the other hand, the rear barrel 5 is positioned and fixed to the back side of the intermediate barrel 4 via the holding unit 8. Specifically, a plurality of positioning projections 5 a that are positioned with respect to the holding unit 8 and screws (not shown) that are screwed to the intermediate lens barrel 4 are passed through the front side of the rear lens barrel 5. A plurality of through holes 5b are formed. On the other hand, on the back side of the holding unit 8 (camera shake correction mechanism 7), a positioning hole (not shown) with which the plurality of positioning projections 5a are engaged and a screw that penetrates the plurality of through holes 5b are passed. A plurality of through holes 8a are formed. Further, a plurality of screw holes (not shown) are formed on the back side of the intermediate barrel 4 to which screws that pass through the plurality of through holes 5b and 8a are screwed.

  The rear lens barrel 5 is positioned with respect to the holding unit 8 by engaging the positioning projection 5a with the positioning hole of the holding unit 8, and the screw of the intermediate lens barrel 4 through the through holes 5b and 8a. A screw is screwed into the hole, so that the holding unit 8 is sandwiched and fixed to the back side of the intermediate barrel 4.

  Inside the intermediate barrel 4, a zoom lens holding member 9 that holds the zoom lens G2, and a pair of guide shafts 10a and 10b that slidably support the zoom lens holding member 9 in the optical axis direction, A zoom lens drive mechanism 11 that drives the zoom lens holding member 9 to be displaced in the optical axis direction along the pair of guide shafts 10a and 10b, and a zoom reset that sets an initial reset position of the zoom lens drive mechanism 11 A switch 12 is provided.

  The zoom lens holding member 9 includes a holding frame 13 that holds the zoom lens G2 on the inside, a first support portion 14 formed with a guide hole 14a through which one guide shaft 10a is inserted, and the other guide shaft. And a second support portion 15 formed with a guide groove 15a with which 10b is engaged. Further, the first support portion 14 and the second support portion 15 are provided at positions that face each other across the optical axis of the zoom lens G <b> 2 on the outer peripheral portion of the holding frame 13.

  The pair of guide shafts 10a and 10b is fixedly supported between the front lens barrel 3 and the holding unit 8 (aperture adjusting mechanism 6) at both ends thereof, so that the optical axis is located inside the intermediate lens barrel 4. Installed in parallel. In the zoom lens holding member 9, one guide shaft 10 a is inserted into the guide hole 14 a of the first support portion 14, and the other guide shaft 10 b is engaged with the guide groove 15 a of the second support portion 15. By this, it is slidably supported in a direction (optical axis direction) along the pair of guide shafts 10a and 10b.

  In addition, the pair of guide shafts 10a and 10b suppresses occurrence of rattling in the zoom lens holding member 9 due to external vibration or the like. The straight line connecting the two support portions 15 is arranged so as to be inclined by approximately 45 ° with respect to the direction of gravity (vertical direction).

  The zoom lens driving mechanism 11 includes a lead screw 17 that meshes with a rack member 16 attached to the zoom lens holding member 9 and a zoom stepping motor 18 that rotationally drives the lead screw 17.

  The lead screw 17 is formed integrally with the drive shaft of the zoom stepping motor 18, and is supported by a bracket 19 between one end and the other end. The bracket 19 is made of a flat plate member whose both ends are bent in the same direction. The zoom stepping motor 18 is fixed in a state where the lead screw 17 is passed through one end, and the lead screw 17 is attached to a bearing provided at the other end. The lead screw 17 is supported so as to be rotatable around the axis.

  The bracket 19 has a plurality of positioning holes 19 a that are positioned with respect to the intermediate lens barrel 4, and a plurality of through holes 19 b that pass through screws (not shown) that are screwed to the intermediate lens barrel 4. Is formed. On the other hand, the intermediate lens barrel 4 has a plurality of screw holes (not shown) into which the positioning projections 4c with which the plurality of positioning holes 19a are engaged and the screws that pass through the plurality of through holes 19b are screwed together. And an insertion port 4d for inserting the lead screw 17 in a state parallel to the optical axis.

  The zoom lens drive mechanism 11 has a lead screw 17 inserted through the insertion port 4d of the intermediate lens barrel 4 and the lead screw 17 is engaged with the rack member 16, and the through hole 19b of the bracket 19 is inserted. The screw is attached to the side surface side of the intermediate barrel 4 by screwing the screw into the screw hole of the intermediate barrel 4.

  Thus, in the zoom lens driving mechanism 11, the zoom stepping motor 18 rotates the lead screw 17, and the zoom lens holding member 9 is moved in the optical axis direction via the rack member 16 meshed with the lead screw 17. It is possible to drive the displacement.

  The zoom reset switch 12 includes a sensor 21 that detects a protrusion 20 provided on the zoom lens holding member 9 and a substrate 22 that holds the sensor 21. The substrate 22 has a plurality of positioning holes 22a that are positioned with respect to the intermediate lens barrel 4 and a plurality of through holes 22b that allow screws (not shown) screwed to the intermediate lens barrel 4 to pass therethrough. Is formed. On the other hand, the intermediate barrel 4 includes a positioning projection 4e with which the plurality of positioning holes 22a are engaged, a plurality of screw holes 4f into which screws that pass through the plurality of through holes 22b are screwed, and a sensor 21. An insertion port 4g for insertion into the inside is formed.

  The zoom reset switch 12 engages the positioning protrusion 4e of the intermediate lens barrel 4 with the positioning hole 22a of the substrate 22 with the sensor 21 inserted through the opening 4g of the intermediate lens tube 4, and A screw is screwed into the screw hole 4 f of the intermediate lens barrel 4 through the through-hole 22 b of the substrate 22, and is attached to the side surface side of the intermediate lens barrel 4.

  The zoom reset switch 12 has a mechanism in which the protruding portion 20 of the zoom lens holding member 9 passes through the inside of the groove portion 21 a formed in the sensor 21 as the zoom lens holding member 9 moves. In the zoom reset switch 12, the sensor 21 can detect a light shielding state in which the protruding portion 20 is located inside the groove portion 21a and a transmission state in which the protruding portion 20 is not located inside the groove portion 21a. ing. In the zoom reset switch 12, the sensor 21 detects the switching between the light shielding state and the light transmitting state, so that the initial reset position of the zoom stepping motor 18 can be set.

  Inside the rear barrel 5, a focusing lens holding member 23 that holds the focusing lens G5, and a pair of guide shafts 24a and 24b that slidably support the focusing lens holding member 23 in the optical axis direction, A focus lens drive mechanism 25 that drives the focus lens holding member 23 to be displaced in the optical axis direction along the pair of guide shafts 24a and 24b, and a focus reset that sets an initial reset position of the focus lens drive mechanism 25 A switch 26 is provided.

  The focusing lens holding member 23 includes a holding frame 27 that holds the focusing lens G5, a first support portion 28 in which a guide hole 28a through which one guide shaft 24a is inserted, and the other guide shaft 24b. And a second support portion 29 formed with a guide groove 29a to be engaged. Further, the first support portion 28 and the second support portion 29 are provided at positions facing each other across the optical axis of the focusing lens G5 on the outer peripheral portion of the holding frame 27.

  The pair of guide shafts 24a and 24b is fixedly supported between the rear lens barrel 5 and the holding unit 8 (camera shake correction mechanism 7) at both ends thereof, and is parallel to the optical axis inside the rear lens barrel 4. It is attached in the state. In the focus lens holding member 23, one guide shaft 24 a is inserted into the guide hole 28 a of the first support portion 28, and the other guide shaft 24 b is engaged with the guide groove 24 a of the second support portion 29. By this, it is slidably supported in a direction (optical axis direction) along the pair of guide shafts 24a and 24b.

  In addition, the pair of guide shafts 24a and 24b suppresses the occurrence of rattling in the focus lens holding member 23 due to external vibrations or the like, so that the first support portion 28 and the first support portion 28 of the focus lens holding member 23 can be prevented. The straight line connecting the two support portions 29 is disposed so as to be inclined by approximately 45 ° with respect to the direction of gravity (vertical direction).

  In addition, the pair of guide shafts 24a and 24b and the pair of guide shafts 10a and 10b reduce the influence of external vibration and the like, so that the first support portion 14 and the second support portion 14 of the zoom lens holding member 9 are reduced. The straight line connecting the support part 15 and the straight line connecting the first support part 28 and the second support part 29 of the focusing lens holding member 23 intersect in a plane perpendicular to the optical axis. Yes.

  The focus lens driving mechanism 25 includes a lead screw 31 that meshes with a rack member 30 attached to the focus lens holding member 23, and a focus stepping motor 32 that rotationally drives the lead screw 31.

  The lead screw 31 is formed integrally with the drive shaft of the focusing stepping motor 32 and is supported by a bracket 33 between one end and the other end. The bracket 33 is made of a flat plate member whose both ends are bent in the same direction. The focus stepping motor 32 is fixed in a state where the lead screw 31 is penetrated at one end, and the lead screw 31 is attached to a bearing provided at the other end. The lead screw 31 is supported so as to be rotatable around the axis.

  The bracket 33 has a plurality of positioning holes 33a that are positioned with respect to the rear barrel 5, and a plurality of through holes 33b that pass through screws (not shown) that are screwed to the rear barrel 5. Is formed. On the other hand, the rear barrel 5 has a plurality of positioning holes (not shown) with which the plurality of positioning holes 33a are engaged, and a plurality of screw holes (with screws that pass through the plurality of through holes 33b). And an insertion port (not shown) for inserting the lead screw 31 in a state parallel to the optical axis.

  The focus lens drive mechanism 25 is inserted through the through hole 33 b of the bracket 33 in a state where the lead screw 31 is inserted into the inside through the insertion port of the rear barrel 5 and the lead screw 31 is engaged with the rack member 30. The screws are screwed into the screw holes of the intermediate lens barrel 4 to be attached to the side surface of the rear lens barrel 5.

  Thus, in the focus lens driving mechanism 25, the focus lens holding member 23 is moved in the optical axis direction via the rack member 30 meshed with the lead screw 31 while the focus stepping motor 32 rotationally drives the lead screw 31. It is possible to drive the displacement.

  The focus reset switch 26 includes a sensor 35 that detects a protrusion 34 provided on the focus lens holding member 23, and a substrate 36 that holds the sensor 35. The substrate 36 has a plurality of positioning holes 36 a that are positioned with respect to the rear barrel 5 and a plurality of through holes 36 b that pass through screws (not shown) that are screwed to the rear barrel 5. Is formed. On the other hand, the rear barrel 5 has a plurality of positioning holes (not shown) with which the plurality of positioning holes 36a are engaged, and a plurality of screw holes (with screws that pass through the plurality of through holes 36b). (Not shown) and an insertion port 5c for inserting the sensor 35 therein.

  The zoom reset switch 26 engages the positioning projection of the rear barrel 5 with the positioning hole 36a of the substrate 36 in a state where the sensor 35 is inserted into the opening 35c of the rear barrel 5 from the inside. A screw is screwed into a screw hole of the rear barrel 5 through a through-hole 36 b of 36, and is attached to the side surface side of the rear barrel 5.

  The focus reset switch 26 has a mechanism in which the protrusion 34 of the focus lens holding member 23 passes through the inside of the groove 35 a provided in the sensor 35 as the focus lens holding member 23 moves. In the focus reset switch 26, the sensor 35 can detect a light shielding state in which the protruding portion 34 is located inside the groove portion 35a and a transmission state in which the protruding portion 34 is not located inside the groove portion 35a. ing. In the focus reset switch 26, the initial reset position of the focus stepping motor 32 can be set by detecting the switching between the light shielding state and the transmission state by the sensor 35.

  The aperture adjusting mechanism 6 supports a pair of shutter members 37a and 37b, and a pair of shutter members 37a and 37b that are slidable in opposite directions in the vertical direction, and have a support member 38 having an opening 38a formed thereon. And a drive motor 39 including a galvanometer that drives the pair of shutter members 37a and 37b to move in opposite directions.

  In the diaphragm adjusting mechanism 6, the pair of shutter members 37a and 37b are slid by driving of the drive motor 39, and the area where the opening 38a is shielded by the pair of shutter members 37a and 37b is changed to thereby adjust the diaphragm. It is possible to adjust the opening of the SP.

  The camera shake correction mechanism 7 includes a holding frame 40 that holds the fourth lens group G4 on the inside, a support frame 41 that supports the holding frame 40 so as to be movable in a plane orthogonal to the optical axis, and the support frame 41. And a vibration actuator 42 composed of a piezo element (PZT) or the like for driving the holding frame 40 in a direction perpendicular to the optical axis.

  In this camera shake correction mechanism, the holding frame 40 is displaced by the vibration actuator 42 with respect to the support frame 41 in a yawing (horizontal) direction and a pitching (vertical) direction orthogonal to each other in a plane orthogonal to the optical axis of the correction lens G4. While driving, it is possible to optically correct image shake due to camera shake or the like.

  The imaging element IP is mounted on the wiring board 44 with the optical filter 43 disposed on the front side. The optical filter 43 is, for example, an infrared cut filter for preventing near-infrared light from reaching the image sensor IP, a low-pass cut filter for extracting a specific spatial frequency component from the light toward the image sensor IP, or It consists of what these filters were pasted together.

  The optical filter 43 is attached to the front surface of the image sensor IP via a support member 45 that is disposed on the wiring board 44 so as to surround the periphery of the image sensor IP. In addition, the wiring board 44 on which the imaging element IP is mounted is attached to the holding plate 46. The imaging element IP is attached to the rear side of the rear barrel 5 via the holding plate 46.

  Specifically, the holding plate 46 is formed with a plurality of through holes 46 a through which screws (not shown) screwed to the rear barrel 5 are passed. On the other hand, on the back side of the rear barrel 5, a plurality of screw holes (not shown) into which screws passing through the plurality of through holes 46a are screwed, an optical filter 43, a support member 45, and an image sensor IP. And the recessed part 5d for positioning the wiring board 44 inside is formed. The imaging element IP is attached to the rear side of the rear barrel 5 by screwing a screw into the screw hole of the rear barrel 5 through the through hole 46 a of the holding plate 46.

  In the imaging apparatus 1 having the above-described structure, the zoom lens G2 is moved in the optical axis direction and zooming is performed, and the image plane of the subject imaged by the plurality of lenses L1 to L14 is changed. Focusing is performed by moving the focusing lens G5 in the direction of the optical axis so that the light receiving surface of the image sensor IP coincides. Accordingly, the focal length can be continuously changed while the image plane of the subject formed by the plurality of lenses L1 to L14 and the light receiving surface of the imaging element IP are matched.

  For example, at the wide end position shown in FIG. 3, by positioning the zoom lens G2 on the foremost side (wide end), the image of the subject imaged on the light receiving surface of the image sensor IP is set to the widest angle (wide). can do.

  On the other hand, at the tele end position shown in FIG. 4, by positioning the zoom lens G2 on the most back side (tele end), the image of the subject formed on the light receiving surface of the image sensor IP is set to the most telephoto (tele) position. can do.

  Further, in this imaging apparatus 1, image blur caused by hand shake or the like can be canceled (cancelled) by moving the correction lens G4 in a direction orthogonal to the optical axis.

  In the imaging apparatus 1, the image of the subject formed by the plurality of lenses L1 to L14 is received by the imaging element IP, and the electrical signal output from the imaging element IP is processed, whereby the subject image is obtained. Corresponding digital image data can be generated.

  By the way, in the imaging apparatus 1 to which the present invention is applied, as shown in the graph of FIG. 6, the initial reset position R between the zoom stepping motor 18 and the focus stepping motor 32 is the zoom lens G2 and the focus. The zoom lens is set at a position that coincides with the inflection point of the zoom tracking curve S indicating the relative positional relationship when the lens G5 is in focus.

  Specifically, the graph shown in FIG. 6 is similar to the graph shown in FIG. 7 above, the horizontal axis indicates the position from the wide angle (Wide) end to the telephoto end (Tele) end, and the vertical axis indicates the focus. The zoom lens G5 indicates the position from the closest end point to the infinite end point of the zoom lens G5, and the zoom tracking curve S indicates the focus lens G5 when the zoom lens G2 is zoomed between the wide angle (wide) end and the telephoto (tele) end. Represents the position where is focused.

  In the imaging apparatus 1, since the in-focus state is maintained on the zoom tracking curve S, the zoom lens G2 and the focus lens G5 driven by the zoom stepping motor 18 and the focus stepping motor 32 described above. The zoom tracking curve S is stored in advance in a control circuit (not shown) of the stepping motors 18 and 32 as position information.

  In the imaging apparatus 1, an initial reset position R between the zoom stepping motor 18 and the focus stepping motor 32 is set every time the power is turned on to accurately trace the stored zoom tracking curve S. Reset operation is being performed.

  Here, in the imaging apparatus 1, the change position of the zoom tracking curve S depends on the switching position between the light shielding state and the transmission state in the zoom reset switch 12 and the switching position between the light shielding state and the transmission state in the focus reset switch 26. The lengths of the protrusions 20 and 34 in the axial direction and the positions of the sensors 21 and 35 are set so as to match the inflection points.

  That is, in the imaging device 1, at the initial reset position shown in FIG. 5, the zoom reset switch 12 switches between the light shielding state and the transmission state, and the focus reset switch 26 switches between the light shielding state and the transmission state. It has become.

  Thus, the initial reset position R of the zoom stepping motor 18 and the focus stepping motor 32 shown in the graph of FIG. 6 can be set to a position that matches the inflection point of the zoom tracking curve S. .

  In the imaging apparatus 1, the zoom reset switch 12 is in the transmissive state and the focus reset switch 26 is in the transmissive state at the wide end position shown in FIG. On the other hand, in the imaging apparatus 1, the zoom reset switch 12 is in a light shielding state and the focus reset switch 26 is in a transmissive state at the telephoto end position shown in FIG.

  Regarding the reset operation of the image pickup apparatus 1, when the image pickup apparatus 1 is turned on, the zoom lens G2 and the focus are changed from the state of the zoom reset switch 12 and the state of the focus reset switch 26. The position with respect to the lens G5 is determined.

  Specifically, when the zoom reset switch 12 is in the transmissive state, it is determined that the zoom lens G2 is on the wide side, and the zoom lens drive mechanism 11 moves the zoom lens G2 to the tele side. To start. On the other hand, when the zoom reset switch 12 is in the light shielding state, it is determined that the zoom lens G2 is on the telephoto side, and the zoom lens drive mechanism 11 starts moving the zoom lens G2 to the wide side. To do.

  Similarly, when the focus reset switch 26 is in the transmissive state, it is determined that the focus lens G5 is on the infinity side, and the focus lens drive mechanism 25 moves the focus lens G5 to the closest side. Start. On the other hand, when the focus reset switch 26 is in the light shielding state, it is determined that the focus lens G5 is on the close side, and the focus lens drive mechanism 25 starts to move the focus lens G5 toward the infinity side. To do.

  The zoom reset switch 12 stops the movement of the zoom lens G2 by the zoom lens driving mechanism 11 at the position where the switching between the transmission state and the light shielding state is detected. Similarly, the focus reset switch 26 stops the movement of the focus lens G5 by the focus lens driving mechanism 25 at the position where the switching between the transmission state and the light shielding state is detected.

  In the imaging apparatus 1, the initial reset position R of the zoom stepping motor 18 and the zoom reset switch 32 can be set by the reset operation as described above. Thereafter, the zoom shown in FIG. 6 described above is performed. Based on the tracking curve S, the stepping motors 18 and 32 drive the zoom lens G2 and the focus lens G5, so that the zooming operation can be accurately performed while maintaining the in-focus state. .

  Here, as shown in the graph of FIG. 6, even when the initial reset position R ′ is set on the zoom tracking curve S, an error X of about ± 0.2 mm occurs at the mounting position of the reset switches 12 and 26. At this initial reset position R ′, the positional deviation Y ′ increases from the zoom tracking curve S, so that a minute blur occurs in the image output when the reset operation is completed.

  On the other hand, in the present invention, the initial reset position R of the zoom stepping motor 18 and the focus stepping motor 32 is set to a position that matches the inflection point of the zoom tracking curve S as described above. Even when an error X occurs in the mounting positions of the reset switches 12 and 26, the positional deviation Y of the initial reset position R from the zoom tracking curve is set to a level at which it is not necessary to perform the focusing operation after the reset operation is completed. Can be reduced.

  In other words, when the initial reset position R ′ is set at a position having a slope on the zoom tracking curve S, the error on the reset position of the reset switches 12 and 26 and the error X on the zoom tracking curve S at the initial reset position R ′. The positional deviation Y from the position increases. On the other hand, since the slope near the inflection point of the zoom tracking curve S is gentle, the positional deviation Y of the initial reset position R from the zoom tracking curve S can be reduced to a level that can be almost ignored (Y <Y ′). Therefore, in the latter case, the degree of occurrence of blur is minute compared to the former case, and it is possible to shorten the time for refocusing by autofocus.

  For example, in the graph shown in FIG. 6, when the coordinates of the initial reset position R at the inflection point of the zoom tracking curve S are (19.3121, 1.95776), the zoom reset switch 16 is attached at about 0 on the wide side. If the coordinates are shifted by 2 mm and the coordinates are (19.1192, 1.63332), the error is 0.00556 mm. On the contrary, when the mounting position of the zoom reset switch 16 is shifted by about 0.2 mm toward the telephoto side and the coordinates are (19.505, 1.96706), the error is 0.00093 mm. Therefore, in any case, the error is within 10 μm, and is suppressed to such an extent that no large blur is generated.

  As described above, the imaging apparatus 1 to which the present invention is applied can output an in-focus image immediately after the reset operation is completed while reducing the time required for the reset operation.

In addition, this invention is not necessarily limited to the thing of the said embodiment, A various change can be added in the range which does not deviate from the meaning of this invention.
For example, in the imaging apparatus to which the present invention is applied, the reset operation can be performed when the power is turned off (OFF). In this case, in the reset operation when the power is turned on, the zoom reset switch 12 switches between the light shielding state and the transmission state, and the focus reset switch 26 switches between the light shielding state and the transmission state. The initial reset position R between the stepping motor 18 and the zoom reset switch 32 can be set immediately. Therefore, it is possible to further reduce the time required for the reset operation when the power is turned on and to output an in-focus image immediately after the reset operation is completed.

  In the zoom and focus lens drive mechanisms 11 and 25, the stepping motors 18 and 32 are used. However, when a drive motor that requires the reset operation is used, the stepping motors 18 and 32 are used. The present invention can be preferably used.

  DESCRIPTION OF SYMBOLS 1 ... Imaging device 2 ... Lens barrel body 3 ... Front lens barrel 4 ... Intermediate lens barrel 5 ... Rear lens barrel 6 ... Aperture adjustment mechanism 7 ... Camera shake correction mechanism 8 ... Holding unit 9 ... Lens holding member for zoom 10a, 10b ... Guide shaft 11 ... Zoom lens drive mechanism 12 ... Zoom reset switch 18 ... Zoom stepping motor 20 ... Projection 21 ... Sensor 23 ... Focus lens holding member 24a, 24b ... Guide shaft 25 ... Focus lens drive mechanism 26 ... Focus reset switch 32 ... Focus stepping motor 34 ... Projection 35 ... Sensor L1-L14 ... Lens G1 ... First lens group G2 ... Second lens group (zoom lens) G3 ... Third lens group G4 ... Fourth lens Group (correction lens) G5: Fifth lens group (focusing lens) SP: Aperture IP ... imaging element S ... zoom tracking curve R ... initial reset position

Claims (4)

A plurality of lenses including a zooming lens and a focusing lens;
A lens barrel body in which the plurality of lenses are arranged in the optical axis direction;
A zoom lens holding member for holding the zooming lens;
A focus lens holding member for holding the focus lens;
A zoom lens driving mechanism for displacing and driving the zoom lens holding member in the optical axis direction;
A focus lens driving mechanism for driving the focus lens holding member to be displaced in the optical axis direction;
A zoom reset switch for setting an initial reset position of the zoom lens driving mechanism;
A focus reset switch for setting an initial reset position of the focus lens driving mechanism;
The initial reset position of the zoom lens drive mechanism and the focus lens drive mechanism matches the inflection point of the zoom tracking curve indicating the relative positional relationship when the zoom lens and the focus lens are in focus. An image pickup apparatus that is set at a position to be operated.   The reset operation for moving the zoom lens holding member and the focus lens holding member to an initial reset position by the zoom lens driving mechanism and the focus lens driving mechanism is performed when power is turned on. The imaging apparatus according to 1.   The imaging apparatus according to claim 1, wherein the reset operation is performed when a power supply is shut off.   The imaging apparatus according to claim 1, further comprising an imaging element that captures an image of a subject formed by the plurality of lenses.

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