JP5144484B2 - Lens frame and lens removal method - Google Patents

Description

  The present invention relates to a lens frame in which a lens is fixed by thermal caulking, and more particularly to a lens frame and a lens removing method that allow a lens fixed by thermal caulking to be easily removed.

2. Description of the Related Art Conventionally, in assembling lenses used in optical equipment, a method of fixing a lens to a lens frame by applying heat and pressure to a plastic lens frame in which the lens is set, so-called heat caulking, is often performed. In Patent Document 1 below, a lens is dropped into a stepped opening provided in a cover member of a film unit with a lens, the cover member that is in contact with the outer peripheral portion of the lens is melted by laser light, and pressure is applied to the lens. In addition, a method for welding a lens to a cover member is described. Patent Document 2 below describes a thermal crimping device capable of assembling a lens to a lens frame with a fixed tightening force by measuring and monitoring a load applied to the lens.
JP 2004-020867 A JP 2008-116803 A

  When the lens is fixed to the lens frame by heat caulking, a heat caulking device as shown in FIG. 14 is used. The lens frame 10 made of an integrally molded product of plastic is placed on the cradle 11 and the lens 12 is dropped into the lens frame 10. The lens 12 is dropped while its outer peripheral surface is in sliding contact with the inner peripheral wall of the cylindrical portion 14 of the lens frame 10, and is positioned so that the optical axis of the lens 12 matches the center of the lens frame 10. When the heating head 15 is lowered, the heater chip 17 heated by the heater 16 presses the distal end portion 14 a of the cylindrical portion 14. The tip portion 14a is integrally connected to the cylindrical portion 14 as a caulking margin protruding upward from the upper surface of the lens 12 as shown in the figure, and is heated and pressed by the heater chip 17 so that the contact surface of the heater chip 17 is provided. Following the shape, the lens 12 is deformed so as to cover the outer periphery of the lens 12 from above, and the lens 12 is fixed to the lens frame 10.

  After fixing the lens 12 to the lens frame 10 in this way, the lens frame 10 is incorporated into the lens barrel through various post processes. For example, a defect occurs in the lens frame 10 during the post process, and the lens 12 itself has When no problem occurs, it is desirable to remove the lens 12 from the lens frame 10 and reuse it. In particular, if the lens 12 is an expensive glass lens, the cost reduction effect due to reuse is great. In order to remove the lens 12 from the lens frame 10 under such circumstances, conventionally, as shown in FIG. 15, a method of placing the lens frame 10 on the cradle 19 and pressing the lens 12 with a press 20 or the like is generally used. It is used.

  However, in the lens 12 that has been crimped by the thermal crimping device shown in FIG. 14, the crimping portion 21 (FIG. 15) formed by bending the crimping margin covers the outer periphery of the lens 12 over the entire circumference. In order to remove the caulking portion 21 while deforming it, the lens 12 must be strongly pressed from the opposite side by the press machine 20. For this reason, there is a concern that pressing marks of the press machine 20 may remain on the surface of the lens 12, or when the lens 12 is vigorously detached from the lens frame 10, it may collide with surrounding objects and damage a part of the lens. is there. Further, when a plurality of lenses are held on the lens frame 10 with an interval ring or the like sandwiched between them, the lenses often collide with each other and the lenses are often chipped or broken.

  The present invention has been made in view of the above circumstances, and its purpose is to allow a lens fixed to the lens frame by heat caulking to be easily removed from the lens frame and reused without requiring a special device. Another object of the present invention is to provide a lens frame and a method for removing the lens.

In order to achieve the above object, the present invention is devised on the lens frame itself so that the lens can be easily detached. For this reason, the lens frame of the present invention is provided with a cylindrical portion protruding in a cylindrical shape so as to cover the outer peripheral surface of the lens supported by the receiving surface on the receiving surface for positioning the lens in the optical axis direction. A lens frame main body formed with an opening through which the light beam passing through the lens passes through the back surface and the tip of the cylindrical portion are integrally molded and bent toward the center of the cylindrical portion by thermal caulking The caulking allowance for holding and fixing the outer peripheral portion of the lens supported by the receiving surface between the receiving surface and the cylindrical portion without penetrating from the outer peripheral surface of the cylindrical portion to the inner peripheral surface side. is formed at a predetermined depth on the outer circumferential surface and communicates the pair of grooves and the pair of grooves linear extending in a direction parallel to the optical axis toward the root side from the front end portion of the tubular portion at the root side the there in the groove of a substantially U-shaped comprising a groove extending in a direction perpendicular to the pair of grooves A substantially U-shaped groove in which the depth of the groove extending in a direction perpendicular to the pair of grooves is formed deeper than the pair of grooves, and the thickness of the corresponding cylindrical portion is partially reduced; And a crushing portion that is surrounded by the substantially U-shaped groove and is crushed from the lens frame body along the substantially U-shaped groove. The crushing portion can be removed more easily by making the depth of the groove communicating on the root side deeper than the pair of grooves and reducing the thickness of the corresponding cylindrical portion. Become.

It is desirable to provide a plurality of the crushing portions according to the lens frame or the outer diameter of the lens. Is effective. Further, it is advantageous to form a convex portion so as to protrude outward in the radial direction from the outer peripheral surface of the cylindrical portion for each crushing portion, and to make it easy to remove the crushed portion from the cylindrical portion using this convex portion. It is . Furthermore , as the crushing portion provided in the lens frame of the present invention, in addition to communicating the pair of grooves formed from the outer peripheral surface of the cylindrical portion provided with the caulking allowance as described above with the grooves formed in the cylindrical portion, It is also possible to adopt a form in which the pair of grooves are communicated with each other by a groove formed at a predetermined depth from the rear surface side of the lens frame main body. By using such a lens frame, even if the lens is firmly fixed to the lens frame with heat caulking, a simple removal method of removing the lens after crushing and removing the crushing part with a simple tool Can be taken.

  According to the present invention, the crushing portion is partially broken by crushing and removing the crushing portion, and the lens can be easily detached from the lens frame. Therefore, the lens is not damaged during removal. Therefore, even if the lens is once firmly fixed to the lens frame by heat caulking, if a problem occurs in the lens frame in the subsequent process, the lens can be removed and reused.

  In FIGS. 1 and 2 showing the lens frame of the present invention, the lens frame 24 is made by integrally molding plastic, and a receiving surface 25 for positioning the lens in the optical axis direction and an opening through which the light beam passing through the lens passes to the back side. 26 has a lens frame main body 30, and a cylindrical tube portion 31 protruding substantially perpendicularly from the receiving surface 25 is integrally formed on the lens frame main body 30. On the outer peripheral surface 31a of the cylindrical portion 31, a boss 33 protrudes at a position that divides the outer peripheral direction into three equal parts. The receiving surface 25 is not necessarily in surface contact with the lens. For example, as shown in FIG. 4, the receiving surface 25 may be a surface continuous with an edge for positioning the lens in the optical axis direction.

  The lens frame 24 is assembled into a zoom lens barrel after fixing the lens, and used as a lens unit for zooming. Therefore, a tap screw is screwed into each of the bosses 33, and a roller serving as a cam follower is rotatably supported on the rear end side of the tap screw. These rollers are engaged with cam grooves of a cam cylinder incorporated in the zoom lens barrel, and perform an action of moving the lens frame 24 holding the lens in the optical axis direction in conjunction with the rotation of the cam cylinder.

  A caulking allowance 35 for heat caulking is provided in a series on the entire circumference of the tip of the cylindrical portion 31. After the lens is assembled in the lens frame 24, the caulking allowance 35 is softened and bent toward the center side of the cylindrical portion 31 by using, for example, the heat caulking device shown in FIG. 14, and is shown in FIG. 3 and FIG. In this way, the caulking portion 38 wraps the outer peripheral portion of the lens 36 over the entire circumference. When the lens 36 is assembled into the lens frame 24, the lens 36 is inserted into the cylindrical portion 31 so as to be dropped. Since the inner diameter of the cylindrical portion 31 is determined in accordance with the outer diameter of the lens 36, the lens 36 is positioned in the in-plane direction by the cylindrical portion 31, and is positioned in the optical axis direction by the receiving surface 25. The

  When the lens 36 is dropped into the cylindrical portion 31, the caulking allowance 35 provided at the distal end portion of the cylindrical portion 31 protrudes slightly above the upper surface of the lens 36. Therefore, heat caulking is performed using the heat caulking device as described above. At this time, after the caulking allowance 35 is pressed and softened and bent by the heater chip, cooling is performed while maintaining an appropriate pressure state as it is. Therefore, in a state where the caulking allowance 35 becomes the caulking portion 38 and is solidified, the lens 36 is sandwiched and fixed between the caulking portion 38 and the receiving surface 25 so that no play occurs in the optical axis direction.

  The variable power lens unit obtained by fixing the lens 36 to the lens frame 24 in this way is incorporated in the zoom lens barrel in a later process. In this subsequent process, a roller is used for linkage with the variable power cam cylinder. The tap screw assembled with is screwed into the boss 33. This screwing operation may require a certain level of skill, and sometimes the tap screw is eccentrically screwed. If even one tap screw is eccentric and fixed to the lens frame 24, it becomes impossible to smoothly move the lens frame 24 in the optical axis direction by rotation of the cam cylinder. Can also be tilted. The boss 33 is provided with a hole 34 for guiding the tap screw. Once the tap screw is eccentrically inserted and the tap screw cannot be screwed in the correct posture, the lens frame 24 becomes an NG product.

  When such a situation occurs, since the lens frame 24 is a plastic molded product, the cost is small. However, since the lens 36 is an expensive part, it is advantageous to remove it from the lens frame 24 and reuse it. It is. For this reason, the crushing part 40 is provided in the cylindrical part 31 so that the lens 36 can be easily removed from the lens frame 24. The crushing portions 40 are provided on the outer peripheral surface 31 a of the cylindrical portion 31 at six locations that divide the outer peripheral direction into six equal parts, and can be easily cut off from the lens frame main body 30.

  These crushing portions 40 are respectively connected to a pair of linear grooves 41, 41 extending from the distal end portion of the cylindrical portion 31 to the root side where the receiving surface 25 is located, and these grooves 41, 41 are connected at the root side. The tube portion 31 is surrounded by a substantially U-shaped groove 43 including a groove 42 extending in the circumferential direction. The substantially U-shaped groove 43 is formed from the outer peripheral surface 31 a of the cylindrical portion 31 to a certain depth, and as a result, a substantially U-shaped thin portion is provided in the cylindrical portion 31. These grooves only have to be devised in the shape of the mold for molding the lens frame 24, and it is not necessary to engrave these grooves in the cylindrical portion 31 by post-processing. As shown in FIG. 2, the pair of grooves 41 is formed at a depth from the outer peripheral surface 31 a of the cylindrical portion 31 to the outside of the caulking allowance 35, but the groove 42 is formed deeper than the groove 41, The base side of the crushing part 40 is integrated with the lens frame body 30 at a thinner part.

  As described above, when an error such as an eccentric screwing of a tap screw occurs during the post-processing process and an NG product is produced as a variable power lens unit, the lens 36 is attached to the lens by a simple lens removing operation as described below. It can be separated from the frame 24. That is, as shown in FIG. 5, a simple tool 45 such as a screwdriver is inserted into the groove 42 formed in the cylindrical portion 31 of the lens frame 24. Of the three grooves constituting the substantially U-shaped groove 43, the groove 42 is formed deepest, so that the tool 45 can be inserted deeply, and the tip of the tool 45 is not aligned when it is twisted in the direction of the arrow in the figure. It will not be easily removed from the groove 42.

  By crushing the tool 45 in the direction of the arrow, the crushing portion 40 is broken along the thin portion corresponding to the substantially U-shaped groove 43. Since the caulking part 35 is thinner than the thickness of the thin part corresponding to the cylindrical part 31 or the substantially U-shaped groove 43, when the crushing part 40 is broken from the cylindrical part 31, the caulking part 35 is also It breaks along the extension line of the break line. Therefore, the crushing part 40 can be easily removed from the lens frame main body 30, and when all of the crushing parts 40 are removed, the cylindrical part 31 is divided into six in the circumferential direction as shown in FIG. The crimping portion 38 held between the two is also divided into six. The clamping force of the lens 36 by the caulking portion 38 has a practically no problem in the state where the outer peripheral portion of the lens 36 is wrapped around the entire circumference, but becomes considerably weak when divided as shown.

  After removing the crushing portion 40 in this way, for example, as shown in FIG. 7, the rod 50 is placed on the pedestal 47 with the back side of the lens frame main body 30 facing upward, and the urethane 49 is attached to the tip. When the lens 36 is pushed from above using the, the lens 36 can be easily detached from the lens frame 24.

  Further, as shown in FIG. 8, when the two lenses 36a and 36b are fixed to the lens frame 52 with the spacing ring 53 interposed therebetween, the crushing portion 40 provided in the cylindrical portion 31 is removed in exactly the same manner. After that, the tip of the tool 54 may be inserted between the receiving surface 25 and the lens 36a through the gap after the excision and bend in the direction of the arrow. Thereby, the lens 36a can be removed while deforming the caulking portion 38 whose strength is weakened, and then the lens 36b can be easily taken out. It should be noted that the lens can be removed more easily if the remaining caulking portion 38 is cut or partially cut in advance with a cutter knife or the like.

  In the said embodiment, the number of the crushing parts 40 and its arrangement | positioning are not necessarily restricted to providing six at equal intervals. For example, the lens frame 24 includes six crushing portions 40 provided at unequal intervals, three provided at equal intervals, and two sets of three sets that are equally spaced apart from each other. Depending on the outer diameter of the lens 36, the number of crushing portions 40 and the arrangement pattern can be appropriately selected. Practically, since most lenses are circular, it is desirable to provide them at positions that equally divide the circumference.

  As shown in FIGS. 9 and 10, the crushing portion 40 is formed such that a convex portion 56 protruding from the outer peripheral surface 31 a is formed on the outer peripheral surface 31 a surrounded by the substantially U-shaped groove 43. Also good. When crushing the crushing part 40, the convex part 56 may be sandwiched between things such as pliers and then torn. Although a step is provided between the pair of grooves 41 and 41 forming the substantially U-shaped groove 43 and the groove 42 connecting the grooves 41 and 41, the grooves 41 and 41 and the groove 42 are formed to have the same depth and are substantially U-shaped. The depth of the groove 43 may be uniform.

  Next, another embodiment will be described. As shown in FIGS. 11 and 12, the lens frame main body 60 is formed in the cylindrical portion 61 at a predetermined depth so as to reach the back surface 62 of the lens frame main body 60 from the front end portion side toward the rear end portion side. A pair of grooves 63, 63 and a connecting groove 64 formed at a predetermined depth from the back surface 62 so as to connect the pair of grooves at the back surface 62, as shown in FIG. A groove 65 having a substantially U-shape when viewed from above is provided. The crushing portion 70 surrounded by the groove 65 is crushed from the lens frame main body 60 along the pair of grooves 63 and 63 and the communication groove 64. Similarly to the method shown in FIG. 5, the crushing part 70 can be removed by inserting a tool into the connecting groove 64 from the back surface 62 side and prying.

1 is a perspective external view of a lens frame according to the present invention. It is sectional drawing of FIG. It is a perspective appearance figure of a lens frame where a lens was crimped. FIG. 4 is a cross-sectional view of FIG. 3. It is explanatory drawing of the method of removing a crushing part. It is a perspective appearance figure of a lens barrel which removed a crushing part. It is a schematic diagram which shows the method of removing a lens. It is a schematic diagram which shows another method of removing a lens. It is a perspective appearance figure of a lens frame provided with a crushing part in which a convex part was formed. FIG. 10 is a cross-sectional view of FIG. 9. It is the perspective view which looked at the lens frame of another embodiment from the back side. It is sectional drawing of FIG. It is the figure which looked at the lens frame shown in FIG. 11 from the back surface side. It is a schematic diagram of a thermal crimping apparatus. It is a schematic diagram explaining the conventional lens removal method.

Explanation of symbols

24, 52 Lens frame 25 Receiving surface 26 Opening 30, 60 Lens frame main body 31, 61 Tube portion 31a Outer peripheral surface 33 Boss 34 Guide hole 35 Caulking allowance 36 Lens 38 Caulking portion 40, 70 Crushing portion 41, 63 Groove 42, 64 Groove to communicate 43, 65 U-shaped groove 45, 54 Tool 56 Projection 62 Back

Claims (6)

A cylindrical portion protruding in a cylindrical shape is provided on the receiving surface for positioning the lens in the optical axis direction so as to cover the outer peripheral surface of the lens supported by the receiving surface, and penetrates the lens from the receiving surface to the back surface side. A lens frame main body formed with an aperture through which the luminous flux passed,
The lens is integrally molded at the tip of the tube, and bent toward the center of the tube by heat caulking, so that the outer periphery of the lens supported by the receiving surface is sandwiched and fixed between the receiving surface And the caulking
Formed at a predetermined depth on the outer peripheral surface of the cylindrical portion without penetrating from the outer peripheral surface of the cylindrical portion to the inner peripheral surface side, in a direction parallel to the optical axis from the distal end side to the root side of the cylindrical portion A substantially U-shaped groove comprising a pair of linear straight grooves extending and a groove extending in a direction perpendicular to the pair of grooves connecting the pair of grooves on the base side, and perpendicular to the pair of grooves A substantially U-shaped groove in which the depth of the groove extending in the direction is formed deeper than the pair of grooves, and the thickness of the corresponding cylindrical portion is partially reduced;
And the substantially enclosed by the groove of the U-shaped crushing section along the groove of the substantially U-shaped is crushed from the lens frame main body,
A lens frame comprising:   The lens frame according to claim 1, wherein a plurality of the crushing parts are provided in an outer peripheral direction of the cylindrical part.   The lens frame according to claim 2, wherein the plurality of crushing portions are provided at positions where the cylindrical portion is substantially equally divided in the outer peripheral direction.   The lens frame according to any one of claims 1 to 3, wherein the plurality of crushing portions are formed with convex portions protruding from an outer peripheral surface of the cylindrical portion. A cylindrical portion protruding in a cylindrical shape is provided on the receiving surface for positioning the lens in the optical axis direction so as to cover the outer peripheral surface of the lens supported by the receiving surface, and penetrates the lens from the receiving surface to the back surface side. A lens frame main body formed with an aperture through which the luminous flux passed,
The lens is integrally molded at the tip of the tube, and bent toward the center of the tube by heat caulking, so that the outer periphery of the lens supported by the receiving surface is sandwiched and fixed between the receiving surface And the caulking
A pair of grooves formed at a predetermined depth so as to reach the rear surface side of the lens frame body from the front end side to the rear end side of the cylindrical portion, and the pair of grooves on the rear surface side of the lens frame body A crushing portion that is surrounded by a communication groove formed at a predetermined depth from the back side of the lens frame main body so as to contact, and is crushed from the lens frame main body along the pair of grooves and the communication groove,
A lens frame comprising: Removing the lens characterized by removing the lens fixed to the lens frame according to any one of claims 1 to 5 from the lens frame after removal by crushing all or part of the crushing part.

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