JP2007093715A - Lens driving mechanism, lens unit and imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the positional accuracy of a movable lens without increasing power consumption; and also to smooth operations. <P>SOLUTION: The lens driving mechanism is provided with: two lead screws 53 and 53 rotated in an axial direction by the driving force of two driving motors 18 and 19; respective pairs of nut parts 56 and 56 which are respectively screwed on the two lead screws and positioned separately in the shaft direction of the lead screw, and at least either of which is coupled with a movable part 10; and two energizing means 59 and 59 respectively energizing the respective pairs of nut parts so as to separate in the shaft direction of the lead screw. The movable part is provided with two mount parts 34 and 42 having mount recessed parts 34b and 42b respectively, and at least either of the two energizing means is provided with an elastic contact part 59c. By inserting the elastic contact part and either pair of nut parts in the mount recessed part, making the elastic contact part elastically contact with the inner surface of the mount part and also making either pair of nut parts contact with the inner surface of the mount part, the movable part is slidably coupled with the elastic contact part and the nut parts. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a technical field regarding a lens driving mechanism, a lens unit, and an imaging apparatus. More specifically, the present invention relates to a technical field in which a biasing unit that biases a pair of nuts that are screwed into a lead screw in a direction separating in the axial direction of the lead screw is provided to improve the positional accuracy of the movable lens and smooth the operation. .

  A lens unit equipped with a lens drive mechanism for moving a lens holder for holding a movable lens in the optical axis direction of the movable lens or in a direction perpendicular to the optical axis direction is a variety of video cameras, still cameras, mobile phones, etc. It is incorporated in the imaging device.

  In such an imaging apparatus, a movable lens constitutes a movable part together with a lens holder that holds the movable lens, and the movable part is moved in two directions orthogonal to the optical axis direction by a lens driving mechanism to cause image shake of the display screen. Some are configured to perform blur correction to correct the above. In addition, depending on the type of the imaging device, there is a configuration in which a blur correction is performed by moving an imaging device such as a CCD (Charge Coupled Device) in two directions orthogonal to the optical axis direction by a lens driving mechanism. .

  In such a lens driving mechanism, the lead screw is rotated by a driving force of a stepping motor or the like, and a nut portion that is screwed to the lead screw is connected to a lens holder that holds the movable lens, and the nut portion is connected to the lead screw. There is one in which the movable lens is moved in the optical axis direction by being sent in a direction corresponding to the rotation direction (see, for example, Patent Document 1).

  In the lens driving mechanism described in Patent Document 1, one guide shaft is inserted into a compression coil spring, a wall portion to which one end portion of the guide shaft is attached, and a bearing portion (bearing sleeve) provided on the lens holder. A compression coil spring is disposed between the two. By using the compression coil spring in this way and urging the lens holder to one side in the axial direction of the guide shaft by the spring force of the compression coil spring, the lens holder is caused by a so-called backlash that is a gap between the lead screw and the nut. I try to prevent rattling.

JP 2004-341392 A

  However, in the conventional imaging apparatus described above, a compression coil spring is disposed between the mounting wall to which one end of the guide shaft is attached and the bearing portion, and the lens holder is biased to one side in the axial direction of the guide shaft. Therefore, the urging force of the compression coil spring against the movable part varies depending on the position of the lens holder in the optical axis direction.

  Therefore, in order to prevent rattling of the lens holder due to backlash, it is necessary to design each part on the basis of the position of the lens holder where the biasing force by the compression coil spring is minimized, and the amount of contraction of the compression coil spring increases and the biasing force When the torque increases, the torque of the stepping motor must be set to a magnitude that can overcome this strong urging force, which increases the power consumption.

  In addition, when the lead screw is rotated by the driving force of a stepping motor or the like and the movable part is moved in two directions, ie, a first direction and a second direction orthogonal to the optical axis direction, blur correction is performed. In this case, it is necessary to smoothly move the movable part independently in the first direction and the second direction.

  Accordingly, an object of the present invention is to overcome the above-described problems, to improve the positional accuracy of the movable lens without increasing power consumption, and to facilitate the operation.

  In order to solve the above-described problems, the lens driving mechanism, the lens unit, and the imaging device of the present invention are rotated around the axis by two driving motors serving as driving sources and the driving force of the two driving motors, respectively. Two lead screws, a pair of nuts screwed into the two lead screws and spaced apart in the axial direction of the lead screw and at least one connected to the movable part, and the pair of nuts Provided with two urging means for urging the portion in a direction separating from each other in the axial direction of the lead screw, and provided with two attachment portions each having an attachment concave portion on the movable part, and at least one of the two urging means being elastic. Provide a contact portion, insert the elastic contact portion and one nut portion into the mounting recess, make the elastic contact portion elastically contact the inner surface of the mounting portion, and remove one nut portion. In contact with the inner surface of the part is obtained by slidably coupled to the movable portion with respect to the elastic contact portion and the nut portion.

  Therefore, in the lens driving mechanism, the lens unit, and the imaging apparatus according to the present invention, a constant urging force is applied to the movable part via the nut part by the urging unit regardless of the position of the movable part.

  The lens driving mechanism according to the present invention is a lens driving mechanism that moves a movable part having a movable lens or an imaging element in two directions of a first direction and a second direction orthogonal to the optical axis direction of the movable lens. Two source drive motors, two lead screws rotated around the axis by the driving force of the two drive motors, and screwed into the two lead screws, respectively, separated in the axial direction of the lead screw And a pair of nut portions at least one of which is connected to the movable portion, and two urging means for urging the pair of nut portions in directions away from each other in the axial direction of the lead screw. Provided, the movable part is provided with two attachment parts each having an attachment concave part, and at least one of the two urging means is provided with an elastic contact part. The nut part is inserted into the mounting recess, the elastic contact part is brought into elastic contact with the inner surface of the mounting part and one nut part is brought into contact with the inner surface of the mounting part, and the movable part is slid against the elastic contact part and the nut part. The connection is possible.

  Therefore, the urging force on the nut portion of the urging means is constant regardless of the position of the movable portion in the optical axis direction, so the driving force of the drive motor may be set to a magnitude corresponding to the constant urging force. The positional accuracy in the moving direction of the movable lens can be improved without increasing the power.

  Moreover, since the movable part is slidably connected to the elastic contact part and the nut part, the movable part can be smoothly moved independently in the first direction and the second direction.

  In the invention described in claim 2, since the urging means is arranged between the pair of nut portions, the arrangement space of the urging means can be minimized, and the lens driving mechanism can be miniaturized. be able to.

  In the invention described in claim 3, since the connecting portions for connecting the respective one end portions of the pair of nut portions are provided and the connecting portions and the pair of nut portions are integrally formed, the number of parts is reduced. be able to.

  The lens unit according to the present invention includes a movable part having a movable lens or an imaging element, and a lens driving mechanism for moving the movable part in two directions of a first direction and a second direction orthogonal to the optical axis direction of the movable lens. The lens unit includes two drive motors that serve as a drive source, two lead screws that are rotated around the axis by the drive force of the two drive motors, and screwed into the two lead screws, respectively. A pair of nut portions that are positioned apart from each other in the axial direction of the lead screw and at least one of which is connected to the movable portion; and a pair of nut portions that are spaced apart in the axial direction of the lead screw. Two urging means for urging, two attachment portions each having an attachment concave portion are provided in the movable part, and at least the two urging means are provided. An elastic contact portion is provided on one side, the elastic contact portion and one nut portion are inserted into the mounting recess, the elastic contact portion is elastically contacted with the inner surface of the mounting portion, and one nut portion is brought into contact with the inner surface of the mounting portion. The movable portion is slidably connected to the elastic contact portion and the nut portion.

  Therefore, the urging force on the nut portion of the urging means is constant regardless of the position of the movable portion in the optical axis direction, so the driving force of the drive motor may be set to a magnitude corresponding to the constant urging force. The positional accuracy in the moving direction of the movable lens can be improved without increasing the power.

  Moreover, since the movable part is slidably connected to the elastic contact part and the nut part, the movable part can be smoothly moved independently in the first direction and the second direction.

  In the invention described in claim 5, the pair of nut portions or the movable portion can be contacted respectively, and when the nut portion or the movable portion comes into contact, the movable portion is in two directions orthogonal to the optical axis direction. Since the restricting part for restricting the movement and the detection means capable of detecting the position information of the movable part with respect to the restricting part are provided, the lead screw can be prevented from biting into the nut part.

  In the invention described in claim 6, since the position detecting sensor for detecting the position of the movable part is used as the detecting means, it is easily detected whether or not the movable part has been moved to the moving end in the moving range. be able to.

  In the invention described in claim 7, since the motion detecting sensor for detecting the presence / absence and amount of movement of the movable part is used as the detecting means, whether or not the movable part has been moved to the moving end in the moving range. Can be easily detected.

  In the invention described in claim 8, since the contact detecting sensor for detecting the presence or absence of contact of the nut portion or the movable portion with the restricting portion is used as the detecting means, whether or not the movable portion has been moved to the moving end. Can be reliably detected, and the reliability of the operation can be improved.

  The imaging apparatus according to the present invention includes a movable part having a movable lens or an imaging element, and a lens driving mechanism for moving the movable part in two directions of a first direction and a second direction orthogonal to the optical axis direction of the movable lens. An imaging apparatus provided with two drive motors that serve as a drive source, two lead screws that are each rotated around an axis by the drive force of the two drive motors, and screwed into the two lead screws, respectively A pair of nut portions that are positioned apart from each other in the axial direction of the lead screw and at least one of which is connected to the movable portion; and a pair of nut portions that are spaced apart in the axial direction of the lead screw. Two urging means for urging, two attachment portions each having an attachment recess in the movable portion, and elastic contact with at least one of the two urging means The elastic contact portion and one nut portion are inserted into the mounting recess, the elastic contact portion is elastically contacted with the inner surface of the mounting portion, and one nut portion is contacted with the inner surface of the mounting portion to elastically contact the movable portion. It is characterized in that it is slidably connected to the portion and the nut portion.

  Therefore, the urging force on the nut portion of the urging means is constant regardless of the position of the movable portion in the optical axis direction, so the driving force of the drive motor may be set to a magnitude corresponding to the constant urging force. The positional accuracy in the moving direction of the movable lens can be improved without increasing the power.

  Moreover, since the movable part is slidably connected to the elastic contact part and the nut part, the movable part can be smoothly moved independently in the first direction and the second direction.

  In the invention described in claim 10, the pair of nut portions or the movable portion can be brought into contact with each other, and when the nut portion or the movable portion comes into contact, the movable portion is in two directions orthogonal to the optical axis direction. Since the restricting part for restricting the movement and the detection means capable of detecting the position information of the movable part with respect to the restricting part are provided, the lead screw can be prevented from biting into the nut part.

  The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. INDUSTRIAL APPLICABILITY The present invention can be applied to various imaging devices having a function of moving image shooting or still image shooting such as a mobile phone, a video camera, a still camera, or various lens units and lens driving mechanisms used in these imaging devices. it can.

  First, the overall configuration of the imaging apparatus 1 will be described (see FIG. 1).

  The imaging device 1 includes a camera block 2, a camera DSP (Digital Signal Processor) 3, an SDRAM (Synchronous Dynamic Random Access Memory) 4, a medium interface 5, a control block 6, an operation unit 7, an LCD (Liquid Crystal Display) 8, and an external interface 9 and the recording medium 100 is detachable.

  As the recording medium 100, various types such as a so-called memory card using a semiconductor memory, a disc-shaped recording medium such as a recordable DVD (Digital Versatile Disk) or a recordable CD (Compact Disc), and the like can be used.

  The camera block 2 includes a movable unit 10, an imaging device 11 such as a CCD (Charge Coupled Device), an A / D conversion circuit 12, a first driver 13, a second driver 14, a timing generation circuit 15, and the like.

  The movable unit 10 includes, for example, a movable lens 16 such as a correction lens for correcting camera shake and image blur, and a lens holder 17 that holds the movable lens 16. The movable portion 10 is moved in two directions (XY directions shown in FIGS. 2 and 3) orthogonal to the optical axis direction.

  As shown in FIG. 1, the image sensor 11 operates according to a drive signal from the second driver 14, captures an image of a subject captured via the movable lens 16, and is controlled by the control block 6. Based on the timing signal output from the generation circuit 15, the captured image of the subject (image information) is sent to the A / D conversion circuit 12 as an electrical signal.

  The imaging element 11 is not limited to a CCD, and other elements such as a CMOS (Complementary Metal-Oxide Semiconductor) can be used as the imaging element 11.

  The A / D conversion circuit 12 performs a CDS (Correlated Double Sampling) process on the input image information as an electric signal, maintains a good S / N ratio, and performs an AGC (Automatic Gain Control) process. All gain control, A / D (Analog / Digital) conversion, image data generation as a digital signal, and the like are performed.

  The first driver 13 sends a drive signal to drive motors 18 and 19 that respectively move the movable unit 10 in two directions orthogonal to the optical axis based on a CPU command (described later) of the control block 6.

  The second driver 14 sends a drive signal to the image sensor 11 based on the timing signal output from the timing generation circuit 15.

  The timing generation circuit 15 generates a timing signal that provides a predetermined timing in accordance with control by the control block 6.

  The camera block 2 is provided with restricting portions 20, 20,. The regulating parts 20, 20,... Are provided two apart from each other in the X direction and the Y direction, which are the moving directions of the movable part 10, for example, arranged at positions where the movable part 10 can be contacted. It serves to regulate the movement of 10 in the X and Y directions.

  The camera block 2 is provided with detection means 21 and 22 (see FIG. 1). As the detection means 21 and 22, for example, a reflective optical sensor is used. The detection means 21 and 22 detect the position of the movable portion 10 by detecting return light reflected by a detection target to be described later. This detection result is sent to the CPU. The detection means 21 and 22 are fixed to the inner surface of a lens barrel (not shown) where the movable part 10 is arranged.

  The camera DSP 3 performs signal processing such as AF (Auto Focus), AE (Auto Exposure), and AWB (Auto White Balance) on the image data input from the A / D conversion circuit 12. Image data that has undergone signal processing such as AF, AE, and AWB is data-compressed by a predetermined method, outputted to the recording medium 100 via the control block 6, and recorded as a file on the recording medium 100.

  The camera DSP 3 is provided with an SDRAM controller 23, and data is read from and written to the SDRAM 4 at a high speed by a command from the SDRAM controller 23.

  The control block 6 includes a micro processing unit (CPU) 24, a RAM (Random Access Memory) 25, a flash ROM (Read Only Memory) 26, a clock circuit 27, and other components connected via a system bus 28. It is a computer and has a function of controlling each part of the imaging device 1.

  The CPU 24 sends a command signal to the second driver 14 and the like via the first driver 13 and the timing generation circuit 15 to operate these units.

  The RAM 25 is mainly used as a work area, such as temporarily storing intermediate results of processing.

  The flash ROM 26 stores various programs executed by the CPU 24, data necessary for each process, and the like.

  The clock circuit 27 is a circuit that outputs the current date, current day, current time, shooting date and time, and the like.

  The operation unit 7 is a touch panel, a control key, or the like provided in the outer casing of the imaging device 1. A signal corresponding to an operation on the operation unit 7 is input to the CPU 24, and a command signal is sent to each unit based on the signal input by the CPU 24. Is sent out.

  The LCD 8 is controlled by, for example, an LCD controller 29 provided in the outer casing and connected to the system bus 28. Various information such as image data based on the drive signal of the LCD controller 29 is displayed on the LCD 8.

  The external interface 9 is connected to the system bus 28. The external device 200 is connected to an external device 200, for example, an external personal computer via the external interface 9, and image data is received from the personal computer and recorded on the recording medium 100, or the image data recorded on the recording medium 100 is externally stored. Can be output to a personal computer. The recording medium 100 is connected to the control block 6 via the medium interface 5 connected to the system bus 28.

  Further, by connecting an external device 200, for example, a communication module, to the external interface 9, for example, it is connected to a network such as the Internet, and various image data and other information are acquired through the network, and these data and information are acquired. The data can be recorded on the recording medium 100, or the data recorded on the recording medium 100 can be transmitted to a target partner through a network.

  The external interface 9 can be provided as a wired interface such as IEEE (Institute of Electrical and Electronics Engineers) 1394, USB (Universal Serial Bus) or the like, or can be provided as a wireless interface using light or radio waves. Is possible.

  On the other hand, the image data recorded on the recording medium 100 is read from the recording medium 100 based on an operation signal corresponding to the operation performed on the operation unit 7 by the user, and is sent to the camera DSP 3 via the medium interface 5. The

  The camera DSP 3 performs data compression decompression processing (decompression processing) on the compressed image data read out and input from the recording medium 100, and the decompressed image data is sent to the LCD controller 29 via the system bus 28. To send. The LCD controller 29 sends an image signal based on the image data to the LCD 8. An image based on the image signal is displayed on the LCD 8.

  A detection object 30 is attached to the lens holder 17 (see FIGS. 2 and 3). For example, the detection object 30 is formed long in the Y direction, and for example, a reflecting plate provided with a plurality of slit-like detection portions in the longitudinal direction is used.

  As shown in FIGS. 2 and 3, the lens holder 17 includes a lens holding portion 31 that holds the movable lens 16, a first supported portion 32 that protrudes from the side surfaces of the lens holding portion 31 to the opposite sides, and a first supported portion 32. The second supported portion 33 and the mounting portion 34 projecting from the second supported portion 33.

  Guide shafts 35, 35 extending vertically (in the Y direction shown in FIGS. 2 and 3) are inserted through the first supported portion 32 and the second supported portion 33, respectively.

  The second supported portion 33 is provided with regulated protrusions 33a and 33a that protrude vertically.

  The mounting portion 34 protrudes from the second supported portion 33 to the side, and has wall portions 34a and 34a that are spaced apart from each other in the vertical direction. A space between the wall portions 34a and 34a of the attachment portion 34 is formed as an attachment recess 34b opened in the X direction.

  The lens holder 17 is supported by the support base 36 so as to be movable in the vertical direction (Y direction).

  The support base 36 includes a base portion 37, first shaft mounting protrusions 38, 38, second shaft mounting protrusions 39, 39 provided on the left and right ends of the base portion 37, and upper and lower ends of the base portion 37. The first bearing projection 40, the second bearing projection 41 and the mounting portion 42 projecting from the first bearing projection 40 are provided.

  The base portion 37 is formed with a transmission hole (not shown) penetrating in the optical axis direction, that is, the front-rear direction.

  Both end portions of the guide shaft 35 inserted into the first supported portion 32 of the lens holder 17 are attached to the first shaft attachment projections 38, 38, respectively, and the second shaft attachment projections 39, 39 are attached to the second shaft attachment projections 39, 39, respectively. Both ends of the guide shaft 35 inserted through the second supported portion 33 of the lens holder 17 are attached. Accordingly, the lens holder 17 is supported by the support base 36 through the guide shafts 35 and 35 so as to be movable in the vertical direction (Y direction).

  The second shaft mounting protrusions 39 and 39 are provided with restricting portions 20 and 20 that protrude in directions toward each other.

  Guide shafts 43, 43 extending in the left-right direction (X direction shown in FIGS. 2 and 3) are inserted through the first bearing protrusion 40 and the second bearing protrusion 41, respectively.

  The first bearing protrusion 40 is provided with regulated protrusions 40a and 40a that protrude left and right.

  The mounting portion 42 protrudes upward from the first bearing protrusion 40 and has wall portions 42a and 42a that are spaced apart from each other on the left and right. A space between the wall portions 42a and 42a of the attachment portion 42 is formed as an attachment recess 42b opened in the Y direction.

  A detection target 44 is attached to the support base 36. The object to be detected 44 is, for example, a reflecting plate that is formed long in the X direction and is provided with a plurality of slit-like detection portions in the longitudinal direction.

  The support base 36 is supported by the fixed base 45 so as to be movable in the left-right direction (X direction). When the support base 36 is moved in the X direction with respect to the fixed base 45, the lens holder 17 and the movable lens 16 held by the lens holder 17 are moved together with the support base 36 in the X direction.

  The fixed base 45 includes a support surface portion 46, mechanism arrangement portions 47 and 48 projecting laterally from the support surface portion 46, and first shaft holding protrusions 49 and 49 provided at both upper and lower ends of the support surface portion 46, respectively. The second shaft holding protrusions 50 and 50 are fixed in a lens barrel (not shown) of the imaging device 1.

  The support surface portion 46 is formed with a light transmission hole (not shown) penetrating in the optical axis direction, that is, the front-rear direction.

  Both ends of the guide shaft 43 inserted through the first bearing protrusion 40 of the support base 36 are attached to the first shaft holding protrusions 49 and 49, respectively. Are attached to both ends of the guide shaft 43 inserted through the second bearing protrusion 41 of the support base 36, respectively. Accordingly, the support base 36 is supported by the fixed base 45 so as to be movable in the left-right direction via the guide shafts 43, 43.

  The first shaft holding protrusions 49 and 49 are provided with restricting portions 20 and 20 that protrude in directions toward each other.

  Lens drive mechanisms 51 and 52 are arranged in the mechanism arrangement portions 47 and 48, respectively (see FIGS. 2 and 3).

  The lens drive mechanisms 51 and 52 have drive motors 18 and 19 respectively as drive sources (see FIG. 4). The drive motors 18 and 19 are, for example, stepping motors, and motor shafts are provided as lead screws 53 and 53.

  The drive motor 18 (19) is attached to a bracket 54 formed in a U-shape, and the bracket 54 is fixed inside the lens barrel. The bracket 54 includes opposing surface portions 54a and 54a that are positioned to face each other in the axial direction of the lead screw 53, and a connecting surface portion 54b that connects the opposing surface portions 54a and 54a.

  In the bracket 54, the drive motor 18 (19) is attached to one opposing surface portion 54a, the lead screw 53 is positioned between the opposing surface portions 54a, 54a, and the leading end of the lead screw 53 rotates to the other opposing surface portion 54a. It is supported freely.

  An anti-rotation bar 55 is attached between the opposing surface portions 54 a and 54 a of the bracket 54 in a state parallel to the lead screw 53.

  Nuts 56 and 56 are meshed with the lead screw 53 so as to be separated from each other in the axial direction. A screw hole 57 and a support hole 58 are formed in the nut portion 56, and a screw groove 57a is formed on a surface on which the screw hole 57 is formed (see FIG. 5).

  The nuts 56 and 56 have screw grooves 57a and 57a engaged with the screw protrusions 53a of the lead screw 53 (see the enlarged view of FIG. 5), and the rotation prevention bar 55 is inserted into the support holes 58 and 58 (FIG. 4). reference). Accordingly, the nut portions 56 and 56 are screwed to the lead screw 53 and supported by the rotation preventing bar 55 so as to be slidable. The rotation prevention bar 55 serves to prevent the rotation of the nut portions 56 and 56 when the nut portions 56 and 56 are fed along with the rotation of the lead screw 53.

  A biasing means 59 is disposed between the nut portions 56 and 56. The biasing means 59 is, for example, a compression coil spring, and both ends in the axial direction are elastically contacted with the nut portions 56 and 56, respectively. Therefore, the nut portions 56 and 56 are urged by the urging means 59 in a direction away from each other in the axial direction of the lead screw 53, and the screw grooves 57a and 57a of the nut portions 56 and 56 are respectively threaded protrusions 53a of the lead screw 53. (See the enlarged view of FIG. 5). The urging force of the urging means 59 is constant regardless of the position of the lens holder 17 or the support base 36 in the moving direction because the distance between the nut portions 56 and 56 is constant.

  As shown in FIG. 4, the urging means 59 includes a coil portion 59a, an arm portion 59b protruding from one end portion of the coil portion 59a, and an elastic contact portion 59c continuous to the arm portion 59b.

  The lead screw 53 is inserted through the coil portion 59a, the arm portion 59b is attached to one nut portion 56, and the elastic contact portion 59c protrudes from the one nut portion 56 toward the lens holder 17 side.

  In the mounting portion 34 of the lens holder 17 and the mounting portion 42 of the support base 36, one nut portions 56, 56 and elastic contact portions 59c, 59c are inserted into the mounting recesses 34b, 42b, respectively, and one nut portion 56, 56 is inserted. Are slidably engaged with the inner surfaces of the one wall portions 34a and 42a, and the elastic contact portions 59c and 59c are elastically contacted with the inner surfaces of the other wall portions 34a and 42a. Therefore, the lens holder 17, the support base 36, and the nut portions 56 and 56 are slidable with respect to each other.

  In the imaging apparatus 1 configured as described above, the drive motor 18, the lead screw 53, the nut portions 56 and 56, and the urging means 59 are constituent elements of the lens drive mechanism 51 that controls movement of the movable portion 10 in the X direction. The drive motor 19, the lead screw 53, the nuts 56 and 56, and the urging means 59 are components of the lens drive mechanism 52 that controls the movement of the movable part 10 in the Y direction. The movable portion 10 is a component of the lens unit 60 (see FIG. 1).

  When the drive motor 18 is rotated in the imaging apparatus 1, the nut portions 56 and 56 are sent in a direction corresponding to the rotation direction of the drive motor 18, and the support base 36 is fixed base as the nut portions 56 and 56 move. 45 is guided by the guide shafts 43, 43 and moved in the X direction shown in FIGS. 2 and 3, which is a direction orthogonal to the optical axis direction. At this time, as described above, the elastic contact portion 59c of the urging means 59 is elastically contacted with the attachment portion 34 of the lens holder 17 and the nut portion 56 is slidably engaged. The lens holder 17 and the movable lens 16 held by the urging means 59 and the nut portion 56 are slid with respect to the support base 36 and moved in the X direction.

  The support base 36 moves in the X direction until the regulated projections 40a and 40a of the first bearing projection 40 come into contact with the regulation units 20 and 20 provided on the first shaft holding projection 49 of the fixed base 45, respectively. It is possible.

  On the other hand, when the drive motor 19 is rotated in the image pickup apparatus 1, the nut portions 56 and 56 are sent in a direction corresponding to the rotation direction of the drive motor 19, and the lens holder 17 and the nut portions 56 and 56 are moved along with the movement of the nut portions 56 and 56. The movable lens 16 held thereby is guided by the guide shafts 35 and 35 with respect to the support base 36 and moved in the Y direction shown in FIGS. 2 and 3 which is a direction orthogonal to the optical axis direction.

  The lens holder 17 moves in the Y direction until the regulated protrusions 33a and 33a of the second supported part 33 come into contact with the restricting parts 20 and 20 provided on the second shaft mounting protrusions 39 and 39 of the support base 36, respectively. It can be moved to.

  As described above, the movable lens 16 is moved in two directions orthogonal to the optical axis direction, that is, the X direction as the first direction and the Y direction as the second direction. Shake correction is performed.

  When the lens holder 17 or the support base 36 reaches the moving end, the lens holder 17 or the support base 36 is brought into contact with the restricting portions 20, 20,. It can be rotated. Therefore, when the lead screw 53, 53 is rotated when the lens holder 17 or the support base 36 is brought into contact with the restricting portions 20, 20,... And the movement of the lens holder 17 or the support base 36 is stopped, The screw protrusions 53a, 53a of the lead screws 53, 53 bite into the screw grooves 57a, 57a,... Of the nut portions 56, 56,. There is a risk of malfunctions such as malfunction of the lens driving mechanisms 51 and 52 and an increase in power consumption due to a load when rotating.

  Therefore, in the imaging apparatus 1, the following means are taken in order to prevent such a problem from occurring.

  The moving positions of the lens holder 17 and the support base 36 are always detected by the detection means 21 and 22, respectively, and the detection results are sent to the CPU 24 as needed to detect that the lens holder 17 or the support base 36 has been moved to the moving end. When this happens, the CPU 24 sends a stop signal to the drive motors 18 and 19 via the first driver 13 to stop the rotation of the drive motors 18 and 19.

  At this time, the lead screws 53 and 53 may rotate for a certain time due to a control time lag from the detection of the inertia of the drive motors 18 and 19 and the movement end of the lens holder 17 or the support base 36 to the stop of the drive motors 18 and 19. However, in the imaging apparatus 1, as described above, the screw grooves 57a and 57a of the nut portions 56 and 56 are always pressed against the screw protrusions 53a and 53a. A constant gap H always exists between the portions 53a and 53a (see the enlarged view of FIG. 5), and the lead screws 53 and 53 rotate due to inertia or the like when the lens holder 17 or the support base 36 reaches the moving end. Even on the one nut portion 56, 56 side, for example, a screw protrusion in the direction of arrow A shown in FIG. 3a, 53a are moved. Therefore, it is possible to prevent the screw protrusions 53a, 53a of the lead screws 53, 53 from getting into the screw grooves 57a, 57a,... Of the nut portions 56, 56,. Further, with respect to the other nut portions 56 and 56 side, the direction in which the screw protrusions 53a and 53a are further pressed against the screw grooves 57a and 57a by the rotation of the lead screws 53 and 53 due to the inertia of the drive motors 18 and 19, for example, 5, the urging members 59 and 59 are elastically deformed, so that the nut portion 56 moves in the direction of the elastic deformation B of the urging members 59 and 59 as the lead screw 53 rotates. Moved. Accordingly, it is possible to prevent the screw protrusions 53a and 53a from getting into the screw grooves 57a and 57a.

  As described above, whether or not the lens holder 17 or the support base 36 has been moved to the moving end in the movement range by using the position detection sensor that detects the position of the lens holder 17 or the support base 36 as the detection means 21 and 22. Can be easily detected.

  The combination of the detection objects 30 and 44 and the detection means 21 and 22 is not limited to the reflection plate and the reflection type optical sensor. For example, a combination of an MR (Magneto Resistance) magnet and an MR sensor, a magnet and a Hall element. Various combinations such as a combination of (Hall sensors) are possible.

  It is also possible to fix the detection bodies 30 and 44 and attach the detection means 21 and 22 to the lens holder 17 or the support base 36 to make them movable.

  Usable detection means 21 and 22 are not limited to position detection sensors that detect the position of the lens holder 17 or the support base 36. For example, the presence or absence and the amount of movement of the lens holder 17 or the support base 36 are determined. It is also possible to use an operation detection sensor such as an encoder to detect. Even when motion detection sensors are used as the detection means 21 and 22, the lens holder 17 or the support base 36 is located at the moving end in the movement range on the basis of the detection result regarding the presence or absence and the movement amount of the lens holder 17 or the support base 36. Whether it has been moved or not can be easily detected.

  Moreover, it is also possible to use a contact detection sensor that detects whether or not the lens holder 17 or the support base 36 is in contact with the restricting portions 20, 20,. The contact detection sensor is configured, for example, by sticking a strain gauge to each of the regulation units 20, 20,. In the case where a contact detection sensor is used as the detection means 21, 22, it is possible to reliably detect whether the lens holder 17 or the support base 36 has been moved to the moving end, and to improve the operational reliability. Can do.

  As described above, in the imaging apparatus 1, the urging force of the urging means 59 against the nut portions 56, 56 is constant regardless of the position of the lens holder 17 or the support base 36 in the moving direction. The driving force (torque) 18 and 19 may be set to a magnitude corresponding to a constant urging force, and the position accuracy in the moving direction of the movable lens 16 can be improved without increasing the power consumption.

  Further, the elastic contact portion 59c of the urging means 59 is elastically contacted with the mounting portion 34 of the lens holder 17, and the nut portion 56 is slidably engaged so that the lens holder 17 is coupled to the lens driving mechanism 52. Therefore, when the support base 36 is moved in the X direction, the lens holder 17 supported by the support base 36 and the movable lens 16 held by the support base 36 smoothly move in the X direction as the support base 36 moves. The movable unit 10 can be moved smoothly and independently in the X direction as the first direction and the Y direction as the second direction.

  Further, since the urging force by the urging means 59 is applied to the nut portions 56 and 56 in opposite directions, the lens holder 17 or the support base 36 is held at a desired position without energizing the drive motors 18 and 19. Power consumption can be reduced.

  Furthermore, in order to prevent the lead screw 53 from biting into the nut portions 56, 56, the range in which the nut portions 56, 56 do not contact the restricting portions 20, 20,. It is not necessary to set the range of movement of the lens holder 17 or the support base 36 so that the nut portions 56, 56 are in contact with the restricting portions 20, 20,. Thus, the imaging apparatus 1 can be downsized.

  Even if the lens holder 17 or the support base 36 and the nut portions 56 and 56 are slidably connected to each other as described above, even if there is an attachment error due to the component accuracy or the attachment accuracy of each part of the lens unit 60. The mounting error is absorbed by the sliding of the lens holder 17 or the support base 36 and the nut portions 56, 56, and the reliability of the operation of the lens unit 60 can be ensured.

  Further, since the urging means 59 is disposed between the pair of nut portions 56, 56, the arrangement space of the urging means 59 can be minimized, and the image pickup apparatus 1 can be reduced in size.

  In the above, an example in which the nut portions 56 and 56 are slidably engaged with both the mounting portion 34 of the lens holder 17 and the mounting portion 42 of the support base 36 is shown. Since it is not necessary to move the support base 36 in the same Y direction when moved in the Y direction by the mechanism 51, for example, the nut portion 56 is fixed to the mounting recess 42b of the mounting portion 42 by press-fitting or bonding. 56 may be connected to the support base 36.

  In the above, an example is shown in which the movement of the lens holder 17 or the support base 36 is restricted when the lens holder 17 or the support base 36 is in contact with the restricting portions 20, 20,. It is also possible to configure so that the movement of the lens holder 17 or the support base 36 is regulated by contacting the regulation parts 20, 20,.

  Furthermore, the drive motors 18 and 19 are not limited to stepping motors, and for example, ultrasonic motors can be used.

  In addition, the case where a compression coil spring is used as the biasing means 59 has been described as an example. However, the biasing means 59 is not limited to the compression coil spring, and an elastic member such as a tension coil spring, a leaf spring, or rubber is used. It is also possible to use as the biasing means 59.

  In the above, screw holes 57, 57 are formed in the nut portions 56, 56, and the lead screw 53 is inserted into the screw holes 57, 57 so that the screw grooves 57a, 57a and the screw protrusions 53a are screwed together. Yes.

  Accordingly, since the lead screw 53 is not clamped so as to be pinched from the opposite side and screwed, vibration generated based on the shaft vibration of the lead screw 53 is not easily transmitted to the lens holder 17 or the support base 36. The occurrence of image shake can be reduced.

  In addition, since it is not configured to clamp, the lead screw 53 does not drop off from the nut portions 56 and 56 due to an impact at the time of dropping or the like, and a problem such as so-called tooth skipping in which the screwing position is shifted does not occur.

  A modification of the lens driving mechanism is shown below (see FIG. 6).

  The lens driving mechanism 61 according to the modification includes a nut body 63 in which one end portions of the nut portions 56 and 56 are connected by the connecting portion 62, and the nut portions 56 and 56 and the connecting portion 62 are integrally formed. ing. The nut body 63 is formed of an elastic material, and the nut portions 56 and 56 are elastically deformable with respect to the connecting portion 62.

  Therefore, due to the urging force of the urging means 59, the nut portions 56, 56 are elastically deformed with respect to the connecting portion 62 and are urged away from each other in the axial direction of the lead screw 53, and the nut portions 56, 56 are screwed. The grooves 57a and 57a are screwed together while being pressed against the screw protrusion 53a of the lead screw 53, respectively.

  In this way, by using the nut body 63 including the nut portions 56 and 56 and the connecting portion 62, the number of parts can be reduced.

  Further, the nut portions 56 and 56 and the connecting portion 62 are integrally formed of an elastic material, and in a state where the nut portions 56 and 56 are screwed to the lead screw 53, the screw grooves 57a and 57a of the nut portions 56 and 56 are always provided. Can be configured to be screwed in a state of being pressed against the screw protrusion 53 a of the lead screw 53. If comprised in this way, since the urging | biasing means 59 is integrally formed with the nut parts 56 and 56, the reduction of the number of parts can be aimed at further.

  In the above, the example in which the movable portion 10 having the movable lens 16 is moved in the X and Y directions using the lens driving mechanisms 51, 52, and 61 to perform the blur correction is shown. However, as shown in FIG. It is also possible to perform blur correction by moving the image sensor 11 in the XY directions instead of the movable portion 10 using 51, 52, and 61. Therefore, in this case, the image sensor 11 becomes the movable portion 10A that is moved by the lens driving mechanisms 51, 52, and 61.

  The configuration for moving the image sensor 11 in the XY directions is the same as the configuration for moving the movable lens 16 in the XY directions. For example, the holder that holds the image sensor 11 is supported by the support base so as to be movable in the X or Y direction. The support base is supported by the fixed base so as to be movable in the Y direction or the X direction, the holder is moved in the X direction or the Y direction by one lens driving mechanism 61, and the support base is moved in the Y direction by the other lens driving mechanism 61. Alternatively, there is an example of moving in the X direction.

  Note that the above-described directions in the up, down, left, and right directions are for convenience of explanation, and the application of the present invention is not limited to these directions.

  The specific shapes and structures of the respective parts shown in the above-described best mode are merely examples of the implementation of the present invention, and the technical scope of the present invention is limited by these. It should not be interpreted in a general way.

FIG. 2 to FIG. 7 show the best mode of the present invention, and this figure is a block diagram showing the overall configuration of the imaging apparatus. It is an enlarged front view which shows a lens unit. It is an expansion perspective view which shows a lens unit. It is an enlarged front view which shows a lens drive mechanism partly in cross section. It is an enlarged front view which shows the screwing state of a nut part and a lead screw by making a part into a cross section. It is an enlarged front view which shows the modification of a lens drive mechanism partly in cross section. It is a conceptual diagram which shows the example which moves an image pick-up element.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Imaging device, 10 ... Movable part, 11 ... Imaging element, 16 ... Movable lens, 18 ... Drive motor, 19 ... Drive motor, 20 ... Regulatory part, 21 ... Detection means, 22 ... Detection means, 34 ... Mounting part, 34b ... Mounting recess, 42 ... Mounting portion, 42b ... Mounting recess, 51 ... Lens driving mechanism, 52 ... Lens driving mechanism, 53 ... Lead screw, 56 ... Nut portion, 59 ... Burning means, 59c ... Elastic contact portion, 60 ... Lens unit, 61 ... Lens drive mechanism, 62 ... Connection part, 10A ... Movable part

Claims (10)

A lens driving mechanism for moving a movable part having a movable lens or an imaging element in two directions of a first direction and a second direction orthogonal to the optical axis direction of the movable lens,
Two drive motors as drive sources,
Two lead screws each rotated in the direction of the axis by the driving force of the two drive motors;
A pair of nut portions that are respectively screwed into the two lead screws and spaced apart in the axial direction of the lead screw and at least one of which is connected to the movable portion;
Two urging means for urging the pair of nut portions in directions away from each other in the axial direction of the lead screw,
Two mounting portions each having a mounting recess are provided on the movable portion,
An elastic contact portion is provided on at least one of the two urging means,
The elastic contact portion and one nut portion are inserted into the mounting recess, the elastic contact portion is elastically contacted with the inner surface of the mounting portion, and the one nut portion is brought into contact with the inner surface of the mounting portion, thereby moving the movable portion to the elastic contact portion and the nut. A lens driving mechanism characterized in that it is slidably connected to the part. The lens driving mechanism according to claim 1, wherein the urging unit is disposed between a pair of nut portions. Providing a connecting portion for connecting each one end of the pair of nut portions;
The lens driving mechanism according to claim 1, wherein the connecting portion and the pair of nut portions are integrally formed. A lens unit comprising a movable part having a movable lens or an imaging device, and a lens driving mechanism for moving the movable part in two directions of a first direction and a second direction orthogonal to the optical axis direction of the movable lens. And
Two drive motors as drive sources,
Two lead screws each rotated in the direction of the axis by the driving force of the two drive motors;
A pair of nut portions that are respectively screwed into the two lead screws and spaced apart in the axial direction of the lead screw and at least one of which is connected to the movable portion;
Two urging means for urging the pair of nut portions in directions away from each other in the axial direction of the lead screw,
Two mounting portions each having a mounting recess are provided on the movable portion,
An elastic contact portion is provided on at least one of the two urging means,
The elastic contact portion and one nut portion are inserted into the mounting recess, the elastic contact portion is elastically contacted with the inner surface of the mounting portion, and the one nut portion is brought into contact with the inner surface of the mounting portion, thereby moving the movable portion to the elastic contact portion and the nut. A lens unit characterized by being slidably connected to the part. The pair of nut parts or the movable part can be brought into contact with each other, and when the nut part or the movable part comes into contact with each other, a regulating part for restricting movement of the movable part in two directions orthogonal to the optical axis direction
The lens unit according to claim 4, further comprising detection means capable of detecting position information of the movable portion with respect to the restriction portion. The lens unit according to claim 5, wherein a position detection sensor that detects a position of the movable portion is used as the detection unit. The lens unit according to claim 5, wherein an operation detection sensor that detects the presence or absence and the amount of movement of the movable part is used as the detection unit. The lens unit according to claim 5, wherein a contact detection sensor that detects presence or absence of contact with the nut portion or the restriction portion of the movable portion is used as the detection means. An imaging apparatus comprising: a movable part having a movable lens or an imaging element; and a lens driving mechanism for moving the movable part in two directions of a first direction and a second direction orthogonal to the optical axis direction of the movable lens. And
Two drive motors as drive sources,
Two lead screws each rotated in the direction of the axis by the driving force of the two drive motors;
A pair of nut portions that are respectively screwed into the two lead screws and spaced apart in the axial direction of the lead screw and at least one of which is connected to the movable portion;
Two urging means for urging the pair of nut portions in directions away from each other in the axial direction of the lead screw,
Two mounting portions each having a mounting recess are provided on the movable portion,
An elastic contact portion is provided on at least one of the two urging means,
The elastic contact portion and one nut portion are inserted into the mounting recess, the elastic contact portion is elastically contacted with the inner surface of the mounting portion, and the one nut portion is brought into contact with the inner surface of the mounting portion, thereby moving the movable portion to the elastic contact portion and the nut. An imaging device characterized by being slidably connected to a part. A regulating part for restricting movement of the movable part in two directions orthogonal to the optical axis direction when the pair of nut parts or the movable part can be brought into contact with each other and the nut part or the movable part comes into contact;
The image pickup apparatus according to claim 9, further comprising a detection unit capable of detecting position information of the movable part with respect to the restriction part.

Images