JP4637724B2 - Lens moving device - Google Patents

Description

  The present invention relates to a lens moving device used in a photographing optical system of a video camera or a digital camera, a finder optical system, an optical system of an endoscope, and more specifically, a shutter mechanism, a diaphragm mechanism, or a shutter mechanism that also serves as a diaphragm. The present invention relates to a lens moving device including the above.

  2. Description of the Related Art Conventionally, in a lens moving device, a lens frame that holds a part of a photographic lens is engaged with two guide rods arranged in parallel to the photographic optical axis, so that the lens frame is parallel to the photographic optical axis. The lens barrel is detachably connected to the drive cylinder formed with a nut portion that is screwed to a feed screw that is rotated by the drive of the motor, by a connecting means such as click coupling, and the rotation of the motor A lens frame that moves in the direction of the photographic optical axis is known (Patent Document 1).

  Also, a digital camera or the like is known that uses a bending optical system in order to reduce the thickness of the body (Patent Document 2). This bending optical system is a bending zoom optical system in which the optical path is bent to the subject side and the image sensor side through a mirror. The first lens group is arranged in the subject side optical path, and the second to fifth lens groups are arranged in order from the mirror side in the optical path on the imaging element side. Among these, the first, third, and fifth lens groups are fixed. For zooming, the second and fourth lens groups are moved in parallel to the optical axis on the image sensor side to thereby change the focal length. Changes. The holding frames for holding the second and fourth lens groups are respectively engaged with a pair of guide rods arranged in parallel with the optical axis on the imaging element side, and the common guide rod can move in the optical axis direction. Guided and anti-rotation action. The pair of guide rods are disposed on both sides of the optical axis.

  A diaphragm and a shutter mechanism are fixed between the second and third lens groups. The shutter mechanism inputs the rotation of the motor to the reduction gear and decelerates, rotates the shutter lever using the rotation, and rotates the two symmetric blades by the rotation of the shutter lever. Each of the two blades rotates around one end in a state where they overlap in the direction of the optical axis, shields the shutter opening when all of them overlap each other, and shutters when a gap is formed between them. Open the opening. The shutter lever is urged by a spring to an open position where the shutter is opened, and is set to a shielding position by energizing the motor. The diaphragm mechanism is configured to perform the diaphragm action by inserting and removing the ND filter on the optical axis by using a motor drive different from that for the shutter.

  Thus, if the shutter mechanism and the diaphragm mechanism are provided separately, two motors are required, which is expensive. A shutter mechanism that also serves as an aperture is known, but the type that rotates two shutter blades each requires a speed reduction mechanism, a spring biasing mechanism, and the like, and the mechanism becomes complicated and the cost is high. Stick.

In view of this, there has been known an electric diaphragm device having a configuration in which two diaphragm blades are slid in one direction intersecting the optical axis to form a diaphragm (Patent Document 3). In this motorized diaphragm device, a pair of diaphragm blades is slidably arranged on a base plate having a shutter opening, the rotation of the motor is converted into a linear motion by the diaphragm blade drive lever, and the linear motion is directly transmitted to the diaphragm spring. Thus, the diaphragm blades are linearly moved in different directions. The aperture blade has an aperture for forming an aperture on the shutter aperture, and the aperture diameter is changed by the amount of overlap between the apertures.
JP 9-33782 A JP 2005-84654 A JP-A-10-254022

  The aperture device described in Patent Document 3 has a simple configuration and is inexpensive. This diaphragm device can also be used as a shutter device. For this reason, it has been desired to employ the diaphragm device in the bending optical system. However, in the bending optical system described in Patent Document 2, a guide rod that guides two moving lenses disposed before and after the shutter and the diaphragm device is disposed. For this reason, when the diaphragm device described above is employed in the bending optical system, there is a problem that the pair of guide rods enter the moving path of the pair of diaphragm blades, and the movement space of the diaphragm blades cannot be taken. In addition, if the diaphragm device is arranged so that the diaphragm blades move in a direction not hitting the pair of guide rods, there is a problem that the imaging optical system becomes thick and hinders downsizing.

  The present invention has been made in order to solve the above-described problem, and has been devised so that the moving path of the slidingly moving shielding plate is not limited to the guide rod that guides the movement of the moving lens, and the entire optical system is made compact. Provided is a lens moving device that can be realized.

  In order to solve the above problems, a shielding device of the present invention includes a moving lens that moves in an optical axis direction; an optical axis that is arranged in parallel with the optical axis and guides movement of the moving lens in the optical axis direction. A guide bar extending in a direction; a base plate disposed in front of or behind the optical axis with respect to the moving lens; and a pair of shielding plates disposed in an overlapping manner in the optical axis direction with respect to the base plate, For shielding provided on the optical axis of the base plate by a part of each shielding plate by linearly moving in one direction intersecting the optical axis and in different directions of the one direction. Shielding of either one of the pair of shielding plates is used in a lens moving device including: a shielding mechanism that changes a state between a state in which the opening is closed and a state in which the shielding opening is opened. The guide rod allows the movement of one shielding plate to the plate and It is provided with a long hole for inserting. The elongated hole may be a wide elongated hole that does not contact the guide bar, or may be an elongated guide hole that contacts the guide bar and guides the movement of one shielding plate.

  Since the pair of shielding plates are arranged so as to overlap with each other in the optical axis direction, a separate pressing member for pressing the pair of shielding plates between the base surface of the base plate on which any one of the shielding plates slides is required. . It is desirable to form the pressing member integrally with the base plate because of low cost. The pressing member may be configured to form a through-opening that sandwiches a pair of shielding plates with the base surface and press the opening through the opening.

  In addition, a pressing member may be provided on the optical axis, and a lens holding portion for fixing the fixed lens to a part of the pressing member on the side opposite to the base surface with the pair of shielding plates interposed therebetween may be provided integrally. Furthermore, the moving lens may be a lens group or a single lens that moves at the time of zooming, focusing, or both.

  In addition, the moving lens may be configured to be arranged before and after the shielding mechanism in the optical axis direction. In this case, it is preferable to use a guide rod having an extended length so as to guide the movement of the pair of moving lenses.

  According to the present invention, since the oblong hole through which the guide rod for guiding the movement of the moving lens is inserted is provided in the shielding plate, the moving path of the shielding plate that linearly slides in one direction intersecting the guide rod is provided. Since the space for securing the guide bar and the space for moving the shielding plate can be overlapped with each other, the entire optical system can be made compact.

  FIG. 1 shows a lens holding unit 10 built in a digital camera. The lens holding unit 10 has a configuration in which a lens moving device, an image sensor, and the like are built in the housing 11 and can be handled integrally. The lens moving device 12 includes a bending optical system 13, a diaphragm / shutter mechanism 14, a lens moving mechanism 15, and the like.

  The bending optical system 13 includes, in order from the subject side, a first lens group 16, a prism 17, and second to fifth lens groups 18 to 21, and the diaphragm / shutter mechanism 14 includes a fourth lens group. 20 and the fifth lens group 21 are fixedly disposed. The prism 17 reflects subject light taken along the first optical axis 22 passing through the center of the first lens group 16 in a right angle direction, and a second optical axis 23 orthogonal to the first optical axis 22. The light is incident on the second to fifth lens groups 18 to 21 arranged above the lens. The subject light reflected by the prism 17 forms an image on the light receiving surface of the image sensor 24. The imaging sensor 24 is, for example, a CCD, and is fixedly disposed behind the fifth lens group 21 in the direction of the second optical axis 23, and converts an image of a subject to be formed into an image signal. The first optical axis 22 is actually bent in the paper direction of FIG. 1, but is bent leftward to make the drawing easier to understand.

  In the bending optical system 13, the first, second, and fourth lens groups 16, 18, and 20 are fixed, and the third and fifth lens groups 19 and 21 move in the direction of the second optical axis 23. To do. The third lens group 19 is held by the third lens holding frame 25. The third lens holding frame 25 is integrally provided with a pair of bearing portions 28 and 29 that engage with the pair of guide rods 26 and 27. The movement direction of the pair of bearing portions 28 and 29 is guided by a pair of guide rods 26 and 27 arranged in parallel with the second optical axis 23. The pair of guide rods 26 and 27 are arranged on both sides of the second optical axis 23, and both ends are fixed by the upper and lower walls 11a and 11b of the housing 11, respectively.

  One bearing portion 28, 29 is formed with a drive portion 31 having a screw portion 30. The screw part 30 is screwed to the feed screw 32. The feed screw 32 serves as an output shaft of the first motor 33 for moving the third lens group 19. Therefore, the third lens group 19 moves in the direction of the second optical axis 23 by driving the first motor 33.

  The fifth lens group 21 is held by the fifth lens holding frame 35. Similarly to the fifth lens holding frame 35, the fifth lens holding frame 35 is integrally provided with a drive unit 39 having a pair of bearing portions 36 and 37 and a screw portion 38. The screw portion 38 is an output shaft of the second motor 40. And the second motor 40 is driven to move in the direction of the second optical axis 23. The bending optical system 13 can change the focal length by moving the third and fifth lens groups 19 and 21, and can adjust the focus by moving the fifth lens group 21.

  As shown in FIGS. 2 and 3, the diaphragm shutter mechanism 14 includes a base plate 45, a drive lever 46, an actuator 47, a pair of shutter blades (shielding plates) 48 and 49, and a fourth lens holding frame 50. It is unitized so that it can be integrated and handled as a unit. The base plate 45 has a long plate shape extending in one direction intersecting the second optical axis 23. The base plate 45 is formed with a base surface 52, a pressing portion 53, a recess 54, a shutter opening 55, and a pair of guide rod insertion holes 56 and 57.

  The base surface 52 is a surface on which one shutter blade 48 slides. The pressing portion 53 is formed on the second optical axis 23. The pair of guide rod insertion holes 56 and 57 are formed on both sides of the pressing portion 53, and the pair of guide rods 26 and 27 are inserted therethrough. One hole 57 is a positioning hole in contact with the entire circumference of the guide rod 26, and the other hole 56 is a hole for stopping rotation of the base plate 45. Thereby, the base plate 45 is positioned in one direction and a direction orthogonal to the pair of guide rods 26 and 27. Note that the positioning in the height direction is performed by the housing 11. The recess 54 is formed at the end of the base surface 52 away from the second optical axis 23, and serves as a space in which the drive lever 46 is rotatably disposed. The shutter opening 55 is disposed on the second optical axis 23 and is an opening for allowing subject light to pass behind the shutter blades 48 and 49.

  The pressing portion 53 has a shape in which a pedestal portion having a rectangular shape in plan view protrudes in the direction of the second optical axis 23 on the front surface of the shutter opening 55, and is formed on both side surfaces 60 and 61 along the one direction. The insertion openings 62 and 63 through which the pair of shutter blades 48 and 49 are inserted are formed. The insertion openings 62 and 63 are connected by a tunnel portion 64. The insertion openings 62 and 63 hold the pair of shutter blades 48 and 49 within a range that allows movement in one direction between the base surface 52 and the pair of shutter blades 48 and 49. The tunnel portion 64 has a height higher than that of the opening edges 62a and 63a, and the dimension between the base surface 52 and the opening edges 62a and 63a is equal to the thickness of the pair of shutter blades 48 and 49. Since the dimensions are the same or slightly wider than this, the friction resistance between the pair of shutter blades 48 and 49 and the base surface 52 and the opening edges 62a and 63a with respect to the pair of shutter blades 48 and 49 The frictional resistance generated between them is reduced.

  The drive lever 46 is rotated between a shield position where the actuator 47 shields the shutter opening 55 and an open position where the shutter 47 is opened. The drive lever 46 is formed with a pair of drive pins 78 and 79. The pair of drive pins 78 and 79 protrude toward the pair of shutter blades 48 and 49 from both sides of the rotation shaft. The actuator 47 is attached to the back surface of the base plate 45. The output shaft penetrates toward the base surface 52, and the drive lever 46 is fixed to the tip thereof. The actuator 47 and the drive lever 46 may be arranged on the opposite side with respect to the base plate 45. In this case, the shutter blades 48 and 49 can be prevented from coming off and the shutter blades 48 and 49 can be prevented from warping.

  The shutter blades 48 and 49 are respectively formed with aperture openings 70 and 71, a pair of elongated holes 72 to 75, and driving openings 76 and 77. The pair of long holes 72 to 75 allow the pair of guide rods 26 and 27 to be inserted therethrough and contact the guide rods 26 and 27 to guide the movement of the pair of shutter blades 48 and 49 in the one direction. A pair of drive pins 78 and 79 engage with the drive openings 76 and 77, respectively.

  When the drive lever 46 rotates to the shielding position, as shown in FIG. 4, one shutter blade 48 slides to the left of the one direction, and the other shutter blade 49 slides to the right. At this time, the pair of aperture openings 70 and 71 do not overlap with each other on the shutter opening 55, so that the shutter opening 55 is closed. When the drive lever 46 is rotated to the open position, as shown in FIG. 5, one shutter blade 48 slides to the right of the one direction, and the other shutter blade 49 slides to the left. . As a result, the pair of aperture openings 70 and 71 are completely overlapped with each other on the shutter opening 55, so that the entire shutter opening 55 is opened.

  When the drive lever 46 is rotated to a position between the shielding position and the open position, a part of the pair of aperture openings 70 and 71 overlap on the shutter opening 55 as shown in FIG. A smaller aperture is formed. The pair of aperture openings 70 and 71 are symmetrical so that the aperture diameter is substantially circular with the second optical axis 23 as the center.

  As shown in FIG. 7, the fourth lens holding frame 50 includes a fourth lens group 20 and a holding frame 100 that holds the fourth lens group 20. The holding frame 100 is integrally formed with a holding section 110 having a circular cross section that holds the fourth lens group 20 and a pair of pieces 101 and 102 protruding from the outer periphery of the holding section 110 in a direction perpendicular to the one direction. These are integrally formed of resin material by mold molding. The pair of pieces 101 and 102 has elasticity and is a part to be pressed when performing eccentricity adjustment.

  In the pressing portion 53, a holding portion 90 that holds the fourth lens holding frame 50 is formed on the upper surface. The holding portion 90 is formed with a contact surface 102 that receives the fourth lens holding frame 50 from below, an adhesion rib 103, and a passage opening 104 for allowing subject light to pass therethrough. The bonding rib 103 is formed so as to protrude one step so as to surround the outer periphery of the holding portion 110, and parts 98 and 99 are cut away to allow the pair of pieces 101 and 102 to escape.

  When the fourth lens holding frame 50 is attached to the holding unit 90, the fourth lens holding frame 50 is inserted into the contact surface 102 from above, and the pair of pieces 101 and 102 are pushed in from above to adjust eccentricity. When the position of the lens group 20 is determined, as shown in FIG. 8, an adhesive is applied and fixed between the bonding rib 103 and the holding portion 110 (reference numerals 124 to 126). Although the location to apply | coat may be arbitrary, about 3 locations are suitable. Then, after fixing, the pair of pieces 101 and 102 are cut at the cutting positions 120 and 121.

  In the above-described embodiment, the pair of elongated holes 72 to 75 are described as examples of the function of guide holes for guiding the movement of the pair of shutter blades 48 and 49. An escape hole that does not contact the guide rods 26 and 27 may be used. In this case, guide means for guiding the movement of the pair of shutter blades 48 and 49 may be provided on the base plate 45 and the shutter blades 48 and 49.

  In each of the above embodiments, the diaphragm / shutter mechanism 14 has been described. However, the present invention is not limited to this, and the diaphragm function, the shutter function, or the shielding function for blocking the photographing light at the front surface of the imaging sensor only. It is good also as the shielding mechanism which has.

  In the above embodiment, the photographing optical system is described as the bending optical system 13, but the present invention is not limited to this. Further, the third and fifth lens groups 19 and 21 arranged on both sides sandwiching the stop / shutter mechanism 14 are described as moving lenses, but the present invention is not limited to this, and only one of these lens groups is configured. There may be.

  In the above embodiment, the optical path of the lens moving device is bent using the prism, but the optical path may be bent using another member, for example, a mirror. Further, the present invention can be used even if the optical path is not a bent optical system. Further, in the present embodiment, the case where the present invention is applied to a digital camera has been described. However, the present invention is not limited to the application to a digital camera, and various optical devices such as a camera using a silver salt film and a projector are used. The present invention can also be applied to a lens moving device.

It is explanatory drawing which shows the imaging optical system of the digital camera which implemented this invention. It is a disassembled perspective view which shows the shutter mechanism also used as an aperture. It is sectional drawing which shows the shutter mechanism used as an aperture stop. It is a top view which shows the shutter mechanism used as the aperture stop in the shielding state. It is a top view which shows the shutter mechanism also as an aperture_diaphragm | restriction in an open state. It is a top view which shows the shutter mechanism used as an aperture stop in the aperture state. It is a principal part perspective view which shows a state when attaching a 4th lens holding frame to a holding | suppressing part. It is a top view which shows the position which apply | coats an adhesive agent between a 4th lens holding frame and an adhesion rib, and the cut position which cut | disconnects a pair of piece after fixation.

Explanation of symbols

13 Bending Optical System 14 Shutter / Shutter Mechanism 24 Imaging Sensor 26, 27 Guide Bar 45 Base Plate 48, 49 Shutter Blade 72-75 Slot

Claims (5)

A moving lens that moves in the direction of the optical axis;
A guide rod arranged in parallel to the optical axis and extended in the optical axis direction to guide the movement of the moving lens in the optical axis direction;
A base plate disposed before or after the moving lens in the optical axis direction;
A pair of shielding plates arranged in an optical axis direction with respect to the base plate are linearly moved in one direction intersecting the optical axis and in different directions of the one direction, A shielding mechanism whose state changes between a state in which a part of each shielding plate closes a shielding opening provided on the optical axis of the base plate and a state in which the shielding opening is opened; In the provided lens moving device,
One of the pair of shielding plates is provided with a long hole through which the one shielding plate is allowed to move and the guide rod is inserted. Mobile equipment.   The lens moving device according to claim 1, wherein the elongated hole is also used as a guide hole that contacts the guide rod and guides the movement of the one shielding plate.   The pressing member for movably pressing the pair of shielding plates between the base plate and the base surface of the base plate on which any one of the shielding plates slides is formed integrally. 3. The lens moving device according to 1 or 2.   The pressing member is disposed so as to protrude on the optical axis, and is used to fix a fixed lens that constitutes an optical system together with the moving lens on the opposite side of the base surface across the pair of shielding plates. The lens moving device according to claim 3, further comprising a lens holding portion. The moving lenses are respectively arranged before and after the optical axis direction with respect to the shielding mechanism,
5. The lens moving device according to claim 1, wherein the guide rod has a length that guides the movement of the pair of moving lenses. 6.

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