JP2010014930A - Lens barrel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a lens barrel which includes: a light quantity control member having an aperture part to be opened/closed; and a lens frame movable between a housing position at which it approaches to the light quantity control member and a photographing position at which it is separated therefrom, where part of the lens frame advances into the aperture part of the light quantity control member at the housing position, and which is further thinned and miniaturized in a housing state by devising shape of a lens supported by the lens frame, especially, a lens positioned closest to the light quantity control member side. <P>SOLUTION: In the lens barrel, a protrusive conical surface whose diameter is reduced toward the aperture part is formed on the outer peripheral surface of the lens supported by the lens frame and positioned closest to the light quantity control member side. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a lens barrel, and more particularly to a lens barrel that can be made thinner and smaller in diameter when stored.

In the lens barrel, in order to reduce the thickness (length in the optical axis direction) of the lens barrel in the stored state, an opening of a light amount control member (for example, a shutter) is opened during storage, and a lens frame that supports the lens in the opening Is stored (Patent Documents 1, 2, and 3).
JP-A-10-111444 JP 2004-347615 A Japanese Patent No. 3496667

  The present invention provides a lens barrel that employs such a storage structure, by devising the shape of the lens that is supported by the lens frame, particularly the lens positioned closest to the light quantity control member, thereby further reducing the thickness of the lens barrel in the storage state. It aims to make it possible.

  The present invention includes: a light amount control member having an opening that opens and closes; and a lens frame that is movable between a storage position approaching the light amount control member and a photographing position that is separated from the light amount control member. In the lens barrel that enters the opening of the light amount control member, a convex cone that is supported by the lens frame and reduces the diameter toward the opening on the outer peripheral surface (edge surface) of the lens located closest to the light amount control member. It is characterized by forming a surface. The convex conical surface is formed outside the effective diameter of the light quantity control member side lens.

  The lens frame is preferably formed with a concave conical surface corresponding to the convex conical surface of the light quantity control member side lens.

  The lens frame can be formed with a cylindrical portion that enters the opening of the light quantity control member around the concave conical surface at the same axial position.

  The end surface of the lens frame on the light quantity control member side is preferably an optical axis orthogonal surface. An annular light shielding member that contacts the outer peripheral edge of the light quantity control member side lens can be provided on the optical axis orthogonal surface.

  The lens barrel of the present invention is suitable when the surface on the light amount control member side of the light amount control member side lens is concave.

  The light control member side lens is preferably a resin lens, and the large-diameter side of the convex conical surface has a large diameter larger than that of the convex conical surface by making the position in the optical axis direction different from that of the convex conical surface. It is preferable to provide a radially outer peripheral portion.

  It is preferable to provide a gate for injection-molding the light quantity control member side lens on the radially outer side of the large-diameter outer peripheral portion.

  In general, the lens frame supports a plurality of lenses including the light quantity control member side lens. At this time, it is desirable to form an optical axis orthogonal surface in contact with the optical axis orthogonal surface of the other lens at the end opposite to the convex conical surface of the light amount control member side lens. The light quantity control member side lens and the other lens can be adjusted in eccentricity with their optical axis orthogonal surfaces in contact with each other, and can be fixed with their optical axis orthogonal surfaces in contact with each other.

  The light quantity control member side lens can be held by a lens frame that holds the other lens via another lens.

  The present invention includes: a light amount control member having an opening that opens and closes; and a lens frame that is movable between a storage position approaching the light amount control member and a photographing position that is separated from the light amount control member. In the lens barrel that enters the opening of the light quantity control member, a convex conical surface that reduces the diameter toward the opening is formed on the outer peripheral surface of the lens that is supported by the lens frame and located closest to the light quantity control member. Therefore, the diameter of the lens entering the opening of the light quantity control member side lens can be minimized. As a result, the diameter of the portion that enters the opening of the lens frame that supports the lens can be reduced, and the lens barrel can be further reduced in thickness and reduced in diameter when stored.

  First, a schematic structure of a zoom lens barrel 70 to which the present invention is applied will be described with reference to FIGS. The imaging optical system of the zoom lens barrel 70 includes, in order from the object (subject) side, a first lens group LG1, a second lens group LG2, a shutter (light quantity control member) S serving as an aperture, a third lens group LG3, and a low-pass filter. 25 and the image sensor 71. In the following description, the optical axis direction means a direction parallel to the optical axis O of the photographing optical system.

  The low-pass filter 25 and the image sensor 71 are unitized and fixed to the image sensor holder 23, and the image sensor holder 23 is fixed to the rear portion of the housing 22. A zoom motor 150 and an AF motor 160 are supported outside the housing 22.

  The third group lens frame 51 that holds the third lens group LG3 is supported so as to be movable in the optical axis direction with respect to the housing 22, and is driven by the AF motor 160.

  A cam ring 11 is supported inside the housing 22. The cam ring 11 is rotated by the driving force of the zoom motor 150 and moves in the optical axis direction while rotating from the lens barrel storage state (FIG. 3) to the photographing state (FIG. 4). In the zoom range (between the wide end in the upper half of FIG. 4 and the tele end in the lower half of FIG. 4), it is rotated at a fixed position in the optical axis direction.

  The first feed cylinder 13 and the straight guide ring 10 are supported with the cam ring 11 in between. The first feeding cylinder 13 and the rectilinear guide ring 10 are each guided in a straight line with respect to the housing 22 in the optical axis direction, and can be relatively rotated with respect to the cam ring 11 and move together in the optical axis direction. Are combined.

  The rectilinear guide ring 10 guides the second group lens moving frame 8 so that it can move relative to the optical axis. Inside the second group lens moving frame 8, a second group lens holding frame 2 that holds the second lens group LG2 and a shutter block 100 that holds the shutter S are supported. Further, the first feeding cylinder 13 guided linearly in the optical axis direction with respect to the housing 22 further guides the second feeding cylinder 12 so as to be relatively movable in the optical axis direction. A first lens group LG <b> 1 is supported inside the second feeding cylinder 12 via a first group lens holding frame 1.

  The second feeding cylinder 12 has a first group cam follower CF1 protruding in the inner diameter direction, and the first group cam follower CF1 is slidably fitted in a first group control cam groove CG1 formed on the outer peripheral surface of the cam ring 11. is doing. Since the second feeding cylinder 12 is guided linearly in the direction of the optical axis via the first feeding cylinder 13, when the cam ring 11 rotates, the second feeding cylinder 12, i.e., the first feeding cylinder 12, according to the shape of the first group control cam groove CG1. The lens group LG1 moves along a predetermined locus in the optical axis direction.

  The second group cam follower CF2 provided on the outer peripheral surface of the second group lens moving frame 8 is engaged with the second group control cam groove CG2 formed on the inner peripheral surface of the cam ring 11. Since the second group lens moving frame 8 is linearly guided in the optical axis direction via the straight guide ring 10, when the cam ring 11 rotates, the second group lens moving frame 8, i.e., the first group moving frame 8 according to the shape of the second group control cam groove CG2. The two lens group LG2 moves along a predetermined locus in the optical axis direction.

  A group biasing spring 27 made of a compression spring is inserted between the second group lens moving frame 8 and the second feeding cylinder 12, and the second group lens moving frame 8 and the second feeding cylinder 12 are separated from each other. Is being energized.

  The zoom lens barrel 70 having the above structure operates as follows. In the lens barrel storage state shown in FIGS. 1 and 3, the length of the optical system in the optical axis direction compared to the imaging state shown in FIGS. 2 and 4 (imaging of the image sensor 71 from the object side surface of the first lens group LG1). The distance to the surface is short. When a transition signal to the photographing state in this lens barrel storage state (for example, a main switch provided in a camera on which the zoom lens barrel 70 is mounted) is input, the zoom motor 150 is driven in the lens barrel feeding direction. The cam ring 11 is fed forward in the optical axis direction while rotating. The rectilinear guide ring 10 and the first feed cylinder 13 move forward together with the cam ring 11. When the cam ring 11 rotates, on the inner side, the second group lens moving frame 8 guided linearly through the straight guide ring 10 is predetermined in the optical axis direction due to the relationship between the second group cam follower CF2 and the second group control cam groove CG2. It is moved by the trajectory. Further, when the cam ring 11 rotates, the second feeding cylinder 12 guided linearly through the first feeding cylinder 13 on the outside of the cam ring 11 is related to the first group cam follower CF1 and the first group control cam groove CG1. Is moved along a predetermined locus in the optical axis direction.

  That is, the first lens group LG1 and the second lens group LG2 are fed out from the lens barrel retracted state by the former moving amount of the cam ring 11 with respect to the housing 22 and the second feeding cylinder 12 with respect to the cam ring 11, respectively. The latter is determined as the sum of the amount of forward movement of the cam ring 11 relative to the housing 22 and the amount of cam extension of the second group lens moving frame 8 relative to the cam ring 11. Zooming is performed by moving the first lens group LG1 and the second lens group LG2 along the photographing optical axis O while changing the air interval between them. When the lens barrel is extended from the housed state, first, the wide end extended state shown in the upper half section of FIG. 4 is obtained. When the zoom motor 150 is further driven in the lens barrel extending direction, the telephoto section shown in the lower half section of FIG. The end is extended. In the zoom region between the tele end and the wide end, the cam ring 11 rotates at the above-mentioned fixed position and does not advance or retreat in the optical axis direction. When a storage state transition signal (for example, turning off the main switch of the camera) is input, the zoom motor 150 is driven in the lens barrel storage direction, and the zoom lens barrel 70 is retracted in the opposite manner to the above-described extension operation. I do.

  Further, a barrier blade 104 capable of opening and closing the front of the first lens group LG1 is provided at the front end portion of the second feeding cylinder 12, and the barrier blade 104 is closed when the lens barrel is housed, so that the shooting state is restored. The barrier blade 104 is opened according to the feeding operation.

  The third lens group frame 51 that supports the third lens group LG3 is moved back and forth in the optical axis direction by the AF motor 160 independently of the driving of the first lens group LG1 and the second lens group LG2 by the zoom motor 150 described above. Can be made. When the optical system is in the zoom range from the wide end to the tele end, the third lens group LG3 is moved in the optical axis direction by driving the AF motor 160 according to the subject distance information obtained by the distance measuring means. Move to perform focusing.

  In the zoom lens barrel 70 described above, the shutter S (light quantity control member) supported by the shutter block 100 has a shutter blade B that opens and closes the optical axis central opening A. In the retracted state, the shutter blade B Open opening A. Such a control system for the shutter S is known. The second group lens holding frame 2 is a lens frame that moves away from the shutter S in the photographing state and moves closer to the shutter S in the housed state, and as shown in FIGS. A part enters the opening A (interference position with the shutter blade B), and the storage length can be shortened.

  The present embodiment is characterized by the structure of the second group lens holding frame 2 that moves toward and away from the shutter S. The embodiment will be described with reference to FIGS. The second group lens holding frame 2 includes three members: a lens holding frame 210, an outer frame 220, and an annular spring member (leaf spring member) 230. The lens holding frame 210 made of a synthetic resin material molding has an annular shape (cylindrical shape) as a whole, and holds (fixes) the second lens LG2 in the central cylindrical portion 211.

  As shown in FIG. 5, the second lens group LG2 has a front lens LG21 and a rear lens LG22 both made of resin, and the front lens LG21 is inserted into the central cylindrical portion 211 from the rear and has a central cylindrical shape. It is positioned by the optical axis orthogonal plane X1 formed on the inner periphery of the portion 211. Optical axis orthogonal surfaces X2 and X3 that are in contact with each other are formed on the rear end surface of the front lens LG21 and the front end surface of the rear lens LG22. By bringing both surfaces into contact with each other, the position of the rear lens LG22 in the optical axis direction can be determined. It is fixed. Further, the rear lens LG22 can perform decentering adjustment (position adjustment in the direction orthogonal to the optical axis with respect to the front lens LG21) with the optical axis orthogonal surfaces X2 and X3 being in contact with each other. The rear lens LG22 is fixed to the front lens LG21 with an adhesive G while the optical axis orthogonal surfaces X2 and X3 are in contact with each other after adjusting the eccentricity, and the adhesive G simultaneously forms the front lens LG21 and the rear lens LG22 in a central cylindrical shape. The part 211 is fixed.

  The rear lens LG22 is a lens closest to the shutter S, and has a convex conical surface (a rotationally symmetric surface about the optical axis) that decreases in diameter toward the rear (opening A of the shutter S) on the outer periphery (lens edge surface) of the rear end. ) C1 is formed. The convex conical surface C1 is formed outside the effective diameter of the rear lens LG22 (the maximum diameter through which the light beam forming the image passes), and the rear end diameter thereof is made as small as possible. The image side (shutter S side) surface of the rear lens LG22 is a concave surface. The shape of the lens located in front of the rear lens LG22 is not limited.

  The rear lens LG22 is provided with a large-diameter outer peripheral portion C4 on the front (large-diameter portion side) outer periphery of the convex conical surface C1, and when the rear lens LG22 is injection-molded on the radially outer side of the large-diameter outer peripheral portion C4. The gate (gate cutting portion) C5 (see FIG. 7) remains. In other words, the gate is formed to protrude in the radial direction on the large-diameter outer peripheral portion C4 that is different in position in the optical axis direction from the convex conical surface C1 of the rear lens LG22. For this reason, the gate is convex at the rear end portion of the rear lens LG22. The conical surface C1 can be formed to reduce the size (diameter).

  A plurality of radial protrusions 213 are integrally formed on the lens holding frame 210 so as to be positioned on the outer periphery of the central cylindrical portion 211. The surface of the radial protrusion 213 on the outer frame 220 side is an optical axis. An annular optical axis orthogonal surface 214 that is orthogonal to each other is formed. The optical axis orthogonal reference plane 214 is formed with a plurality of tapered tapered protrusions 215 that are positioned on the same circumference and project in a direction parallel to the optical axis.

  The outer frame 220 made of a synthetic resin material has a ring shape (cylindrical shape) that is larger in diameter than the lens holding frame 210 as a whole, and the second group cam follower CF2 projects from the outer periphery of the largest outer cylindrical portion. Yes. As shown in FIGS. 5 and 6, the outer frame 220 is formed with an annular optical axis orthogonal reference surface 221 with which the optical axis orthogonal reference surface 214 of the lens holding frame 210 abuts. Four tapered holes 222 corresponding to the four tapered tapered protrusions 215 of the lens holding frame 210 are formed on the reference surface 221.

  The outer frame 220 has a conical wall portion 224 that extends to the outer periphery of the rear lens LG22 behind the radial wall portion 223 having the optical axis orthogonal reference surface 221 (on the shutter S side). The conical wall 224 corresponds to the macroscopic convex conical surface formed by the central cylindrical portion 211 of the lens holding frame 210, the adhesive G, and the convex conical surface C1 of the rear lens LG22, and is on the opening A side of the shutter S. A concave conical surface C2 corresponding to the convex conical surface C1 of the rear lens LG22 (located on the outer periphery of the convex conical surface C1) is formed on the inner periphery of the rear end portion LG22. Has been. A cylindrical portion C3 that enters the opening A of the shutter S is formed in the conical wall portion 224 of the outer frame 220 at the same axial position as the concave conical surface C2. The rear end surface S1 of the outer frame 220 (conical wall portion 224) is a surface orthogonal to the optical axis, and an annular light shielding member S2 that contacts the outer peripheral edge of the rear lens LG22 is bonded to the rear end surface S1.

  The lens holding frame 210 and the outer frame 220 are positioned in the radial direction at the fitting portion therebetween, and are positioned in the thrust direction by the contact engagement between the optical axis orthogonal reference surface 214 and the optical axis orthogonal reference surface 221, and are tapered. Positioning in the rotational direction is performed by the fitting relationship between the tapered protrusion 215 and the tapered hole 222. The annular spring member 230 supports (fixes) the lens holding frame 210 and the outer frame 220 in a state where the optical axis orthogonal reference surface 214 and the optical axis orthogonal reference surface 221 are in close contact with each other. A plurality of insertion cutouts 231 positioned at the periphery of the annular spring member 230 and a cantilever spring arm 234 extending in the circumferential direction are formed on the annular spring member 230 formed of a disk-shaped leaf spring as a whole. The outer frame 220 is formed with a retaining protrusion 225 corresponding to the insertion notch 231. When the positions of the insertion notch 231 and the retaining protrusion 225 coincide with each other, the optical frame orthogonal reference plane 221 side is formed. Can move closer. After the approaching movement, relative rotation can be performed on the back surface of the retaining projection 225. When the relative rotation is performed, the front surface of the annular spring member 230 (left side in FIG. 6) and the back surface of the retaining projection portion 225 (right side). And the cantilever spring arm 234 presses and fixes the lens holding frame 210 against the outer frame 220.

  As described above, the second lens group 2 of the zoom lens barrel 70 of the present embodiment is closest to the shutter S at the storage position, and a part of the rear end thereof enters the opening A of the shutter S. Since the rear lens LG22 supported by the second lens group 2 has a convex conical surface C1 whose diameter decreases toward the opening A on the outer periphery of the rear part, the rear end part diameter can be minimized. For this reason, the outer diameter of the cylindrical portion C3 of the outer frame 220 located on the outer peripheral side of the rear lens LG22 can be made as small as possible. That is, the concave conical surface C2 of the outer frame 220 can be inclined according to the convex conical surface C1 of the rear lens LG22, and the size of the cylindrical portion C3 can be reduced according to this inclination. This is because the size of the outer frame 220 is determined according to the size of the rear lens LG22.

  Further, since the rear lens LG22 is a resin lens, there is an advantage that it can be provided at a low cost. On the other hand, there is a possibility that the influence of internal distortion or the like at the time of injection molding remains within the effective diameter and affects the photographed image. In the present embodiment, the rear lens LG22 has a large-diameter outer peripheral portion C4 having a larger diameter than the convex conical surface C3, and the molding gate C5 is formed on the outer side in the radial direction of the large-diameter outer peripheral portion C4. The gate C5 can be placed at a position sufficiently separated from the effective lens diameter without increasing the overall diameter (enlarging), and the influence of internal distortion can be made less likely to occur. Furthermore, since the surface on the shutter S side of the rear lens LG22 is a concave surface, the outermost diameter portion through which the lens effective ray passes is more likely to protrude from the lens center surface to the shutter opening side as compared to the convex surface. Although it becomes difficult to insert into the opening A further, in this embodiment, since the convex conical surface C3 is formed on the opening A side, it is inserted into the opening A even if the final surface is concave. It becomes easy.

  In the above embodiment, the shutter S is exemplified as the light amount control member. However, the diaphragm device and the ND filter device are also light amount control members having an opening portion that is an object of the present invention.

It is an external appearance perspective view of the storage state of the zoom lens barrel to which the present invention is applied. It is an external appearance perspective view of the photographing state of the zoom lens barrel. It is sectional drawing of the accommodation state of the zoom lens barrel. It is sectional drawing of the imaging state of the zoom lens barrel. From the zoom lens barrel shown in FIGS. 1 to 4, a light quantity control member (shutter) having an opening to open and close, and a lens frame movable to a storage position approaching the light quantity control member and a photographing position separating from the storage position are taken out. It is the upper half sectional view drawn. It is a disassembled perspective view which decomposes | disassembles and shows the same moving lens frame. It is the perspective view drawn from the opposite direction to Drawing 6 of the lens holding frame simple substance in the movement lens frame.

Explanation of symbols

S Shutter (light quantity control member)
A Opening C1 Convex conical surface C2 Concave conical surface C3 Cylindrical part C4 Large diameter outer peripheral part C5 Gate (gate cutting part)
S1 Rear end face (optical axis orthogonal face)
S2 annular light shielding member LG21 front lens (other lens)
LG22 Rear lens (lens closest to the light control member)
DESCRIPTION OF SYMBOLS 1 1st group lens holding frame 2 2nd group lens holding frame 210 Lens holding frame 220 Outer frame 221 Optical axis orthogonal reference surface 223 Radial direction wall part 224 Conical wall part 230 Annular spring member

Claims (12)

A light quantity control member having an opening for opening and closing; and a lens frame movable between a storage position approaching the light quantity control member and a photographing position separating from the storage position;
With
In the storage position, in the lens barrel in which a part of the lens frame enters the opening of the light amount control member,
A lens barrel characterized in that a convex conical surface whose diameter is reduced toward the opening is formed on an outer peripheral surface of a lens that is supported by the lens frame and located closest to the light quantity control member. 2. The lens barrel according to claim 1, wherein the lens frame is formed with a concave conical surface corresponding to the convex conical surface of the light quantity control member side lens. 3. The lens barrel according to claim 2, wherein the lens frame is formed with a cylindrical portion that enters into the opening of the light amount control member around the same axial position of the concave conical surface. 4. The lens barrel according to claim 1, wherein an end surface on the light amount control member side of the lens frame is an optical axis orthogonal surface. 5. 5. The lens barrel according to claim 1, wherein an annular light-shielding member that is in contact with an outer peripheral edge of the lens on the light amount control member side is provided on the surface orthogonal to the optical axis. 6. The lens barrel according to claim 1, wherein a surface on the light quantity control member side of the light quantity control member side lens is a concave surface. 7. The lens barrel according to claim 1, wherein the light quantity control member side lens is a resin lens, and the convex conical surface is positioned in the optical axis direction on the large diameter side of the convex conical surface. A lens barrel in which a large-diameter outer peripheral portion having a diameter larger than that of the convex conical surface is provided. 8. The lens barrel according to claim 7, wherein a gate at the time of injection molding is provided on a radially outer side of the large-diameter outer peripheral portion. 9. The lens barrel according to claim 1, wherein the lens frame supports a plurality of lenses including the light quantity control member side lens, and the light quantity control member side lens has a convex shape. A lens barrel in which an optical axis orthogonal surface that contacts an optical axis orthogonal surface of another lens is formed at an end opposite to the conical surface. 10. The lens barrel according to claim 9, wherein the light quantity control member side lens and the other lens can be adjusted in eccentricity in a state where the surfaces orthogonal to each other are in contact with each other. 11. The lens barrel according to claim 9, wherein the light quantity control member side lens and the other lens are fixed in a state where the optical axis orthogonal planes are in contact with each other. 12. The lens barrel according to claim 9, wherein the light amount control member side lens is held by the lens frame that holds the other lens via the other lens. Tube.

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