JP2017173744A - Lens supporting structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a lens supporting structure capable of facilitating the handling of a lens, facilitating centering work to a lens barrel, improving positional accuracy, and suppressing an increase in an outer diameter.SOLUTION: A lens supporting structure has a lens frame which has a cylindrical portion in which at least one lens is inserted, and a plurality of lens receiving portions protrusively formed inward in a diametrical direction and separated in a circumferential direction at an end portion on the opposite side to a lens insertion side end portion of the cylindrical portion, and holds the lens; and a lens barrel in which the lens frame is inserted and fixed. The lens has a lens reference surface at an end portion on the lens receiving side. The lens frame has a position regulating surface on which the lens reference surface abuts, on the lens insertion side of the lens receiving portion. The lens barrel has a plurality of position reference surfaces abutting on the lens reference surface of the lens held by the lens frame, between the lens receiving portions adjacent to each other.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a support structure for supporting a lens (group) on a lens barrel, and in particular, facilitates handling of the lens (group), facilitates alignment work on the lens barrel, and increases positional accuracy (adjustment accuracy). The present invention relates to a lens support structure that can suppress an increase in outer diameter.

  In a lens barrel having a plurality of lens groups, a specific lens (group) of the lenses (group) is positioned as an alignment lens and then fixed within an optical axis orthogonal plane ( Patent Document 1). During this adjustment, it is desirable to prevent the operator from touching the lens (group) directly in order to avoid damaging the coating applied to the lens or scratching the lens itself. The demand is particularly high for large-diameter lenses and high-grade glass lenses.

  Conventionally, as shown in FIG. 5B, the first lens L1 ′ closest to the object is inserted into the cylindrical portion 22 ′ from the rear, and the lens surface (front surface) is at the front end of the cylindrical portion 22 ′. It is positioned and supported by contacting the formed inner flange 22f (Patent Document 2). In this conventional lens support structure, it is necessary to increase the diameter of the first lens L1 'so that the light incident on the front surface of the first lens L1' is not directed to the inner flange 22f.

JP 2012-173527 A JP 2010-8743 A

  The present invention proposes a lens support structure that meets such requirements for the prior art.

  In the present invention, in order to prevent the operator from directly touching the lens, the lens is supported on the lens frame, while the reference surface formed on the lens and the lens barrel are formed in order to increase the positional accuracy between the lens and the lens barrel. This is based on the viewpoint of direct contact with the position reference plane.

  The lens support structure according to the present invention is formed to project radially inward from a cylindrical portion into which at least one lens is inserted and an end portion of the cylindrical portion opposite to the lens insertion side end portion. A lens frame that holds the lens; and a lens barrel into which the lens frame is inserted and fixed. The lens is disposed on the lens receiving side. A lens reference surface at an end; the lens frame has a position regulating surface that abuts the lens reference surface on the lens insertion side of the lens receiving portion; and the lens barrel is adjacent to the lens A plurality of position reference surfaces that are in contact with the lens reference surface of the lens held by the lens frame;

  It is practical that a concave portion for accommodating the lens receiving portion of the lens frame is formed between the plurality of position reference planes of the lens barrel.

  In one embodiment, the lens frame holds the lens inserted in the cylindrical portion between the position regulating surface and a heat caulking portion formed at the lens insertion side end of the cylindrical portion. doing.

  The lens barrel can move the lens and the lens frame in a direction orthogonal to the optical axis in a state where the lens reference surface of the lens held in the lens frame inserted in the lens barrel is in contact with the position reference surface. It is preferable to have a loosely fitting tube portion that is loosely fitted.

  It is desirable that the lens barrel is formed with an alignment recess for holding the lens frame inserted into the lens barrel and an adhesive recess for bonding the lens frame to the lens barrel.

  It is practical that the lens barrel has a holding cylinder portion that holds a lens different from the lens of the lens frame inserted from the side opposite to the lens insertion side.

  The lens receiving portion of the lens frame is in contact with the image side surface of the at least one lens.

  Specifically, the at least one lens is the most object side lens.

  According to the lens support structure of the present invention, the possibility that an operator directly touches the lens is low, and the positional accuracy (adjustment accuracy) can be increased.

It is a disassembled perspective view which shows one Embodiment of the lens support structure by this invention. It is the disassembled perspective view seen from the direction opposite to FIG. (A) is a front view of a lens barrel, (B) is a front view of a lens frame. It is sectional drawing which follows the IV-IV line of FIG. 3 (A). (A) shows the caulking aspect of the lens frame of this invention, (B) is sectional drawing corresponding to FIG. 4 which shows the caulking aspect of the conventional lens frame.

  Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. In the present embodiment, the first lens (most object side lens, front lens single lens) L <b> 1 is fixed to the first group lens frame 20, and then aligned and fixed to the lens barrel 10. The illustrated elements are only the first lens L1, the lens barrel 10, the first group lens frame 20, and the second lens L2. Hereinafter, forward and backward are defined based on the optical axis O of the first lens L1 (second lens L2).

  As apparent from FIG. 4, the first lens L1 has a convex surface a having a large curvature radius (small curvature) on the front surface and a front circular negative surface having a concave surface b having a small curvature radius (large curvature) on the rear surface. The meniscus lens has a front large-diameter columnar surface c and a rear small-diameter columnar surface d on the outer periphery. The large-diameter columnar surface c and the small-diameter columnar surface d are cylindrical outer peripheral surfaces (cylindrical surfaces) centered on the optical axis O. Between the large-diameter columnar surface c and the small-diameter columnar surface d, a lens reference surface (optical axis orthogonal surface) s orthogonal to both the columnar surfaces c and d (optical axis O) is formed. A chamfering f is provided at the intersection between the convex surface a and the large-diameter columnar surface c.

  The first group lens frame 20 is an annular member made of a molded product of a resin material, and includes a cylindrical portion 22 having an inner cylindrical surface 21 corresponding to the large-diameter columnar surface c of the first lens L1, and the cylindrical portion 22. A flange portion 23 protruding outward in the radial direction and a rear end portion (end portion opposite to the lens insertion side) of the cylindrical portion 22 are protruded radially inward at 120 ° equidistantly in the circumferential direction. Individual lens receivers 24. The front surface of the lens receiving portion 24 (the surface on the lens insertion side) is in contact with the lens reference surface s of the first lens L1 to determine the position of the first group lens frame 20 and the first lens L1 in the optical axis direction. The surface 24a is configured. In FIG. 3B, the position restricting surface 24a is hatched. The front end portion (end portion on the lens insertion side) of the cylindrical portion 22 has a simple cylindrical shape as shown by a chain line in FIG. 4 before the first lens L1 is inserted, but as shown by a solid line in FIG. When bent along the chamfer f of the first lens L1 (caulked or heat caulked), the caulking portion 22a is formed.

  The lens barrel 10 has a large cylindrical portion 11, and a plurality of rectilinear guide protrusions 12 are formed on the outer peripheral surface of the rear portion of the large cylindrical portion 11 so as to protrude in the circumferential direction (see FIG. 3A). A lens support flange 13 is formed at the front end of the lens barrel 10 (large cylindrical portion 11) inward in the radial direction. The lens support flange 13 holds the first group lens frame 20 and the second lens L2 that hold the first lens L1, and in order from the inner diameter side, the holding cylinder portion 13a that holds the second lens L2, and the first lens. A loose fitting cylindrical portion 13b for loosely fitting the small-diameter columnar surface d of L1 and a loose fitting cylindrical portion 13c for loosely fitting the cylindrical portion 22 of the first group lens frame 20 are formed in a stepped cross section (FIG. 4).

  A radially inward position restricting flange 13a1 is formed at the front end portion of the holding cylinder portion 13a, and the position restricting flange 13a1 and the front end outer peripheral step portion g of the second lens L2 come into contact with each other to form a second portion. The position of the lens L2 in the optical axis direction is determined.

  The loose-fitting cylinder portions 13b and 13c are connected by a connecting wall 14 in the radial direction, and three position reference surfaces 14a and relief recesses 14b are arranged on the front surface of the connecting wall 14 at 120 ° in the circumferential direction. It is formed alternately. In FIG. 3A, the position reference surface 14a is hatched. The relief recess 14 b is a portion where the lens receiving portion 24 of the first group lens frame 20 is positioned in a non-contact manner (inserted or accommodated), and the position reference surface 14 a is held by the first group lens frame 20. This is the part where the reference surface (optical axis orthogonal surface) s of the lens L1 contacts.

  The lens barrel 10 is provided with a support surface 15 facing the flange portion 23 of the annular first group lens frame 20 on the outer peripheral side of the loosely fitting tube portion 13c. The support surface 15 is an optical axis orthogonal surface 15a on the inner peripheral side, an optical axis orthogonal surface 15b on the outer peripheral side, and a part projecting forward toward the outer periphery, connecting the optical axis orthogonal surface 15a and the optical axis orthogonal surface 15b. A conical inner surface 15c. An optical axis on the inner peripheral side corresponding to the optical axis orthogonal surface 15a on the inner peripheral side, the optical axis orthogonal surface 15b on the outer peripheral side, and a part of the conical inner surface 15c is provided on the flange portion 23 of the first group lens frame 20. An orthogonal surface 23a, an optical axis orthogonal surface 23b on the outer peripheral side, and a partial conical surface 23c that connects the optical axis orthogonal surface 23a and the optical axis orthogonal surface 23b and protrudes forward toward the outer periphery are formed.

  Further, the lens support flange 13 of the lens barrel 10 is partly positioned on the outer peripheral side of the conical inner surface 15c and is equally spaced by 90 ° in the circumferential direction, and each of the four alignment recesses 16 and the adhesive recesses. 17 are alternately formed.

  In the lens support structure having the above configuration, the first lens L1 is fixed to the first group lens frame 20 as described below, and then the first group lens frame 20 is positioned (aligned) to the lens barrel 10 and fixed. That is, the first lens L1 is inserted into the inner cylindrical surface 21 (cylindrical portion 22) of the first group lens frame 20 from the front, and the lens reference surface s of the first lens L1 is brought into contact with the position regulating surface 24a of the lens receiving portion 24. Make contact. In this state, the front end portion of the cylindrical portion 22 is heat caulked.

  When the caulking is completed, the operator can handle the first group lens frame 20 without touching the first lens L1, so that the possibility of damaging the first lens L1 is reduced, and the work is facilitated.

  The first group lens frame 20 to which the first lens L1 is fixed is then inserted into the loose fitting cylinder portions 13b and 13c of the lens barrel 10. At this time, the lens receiving portion 24 is aligned with the escape recess 14b. In this state, the loose fitting cylindrical portion 13b of the lens barrel 10 and the small-diameter columnar surface d of the first lens L1 are loosely fitted, and the loose fitting cylindrical portion 13c of the lens barrel 10 and the cylindrical portion 22 of the first group lens frame 20 are idle. Since the lens receiving portion 24 of the first group lens frame 20 is loosely fitted (accommodated) in the relief recess 14b of the lens barrel 10, the first group lens frame 20 (first lens L1) is freely movable in the radial direction. it can. On the other hand, since the lens reference surface s abuts on the position reference surface 14a of the first lens L1, the position in the optical axis direction and surface tilt (inclination of the optical axis) are restricted.

  While the lens reference surface s of the first lens L1 is in contact with the position reference surface 14a, the first group lens frame 20 is held by the alignment jig inserted into the alignment recess 16 of the lens barrel 10. The frame 20 is moved (aligned) in the plane orthogonal to the optical axis. After the alignment is completed, an adhesive is put into the adhesive recess 17 to fix the lens barrel 10 (lens support flange 13) and the first group lens frame 20 (first lens L1).

  As described above, in the first lens L1, the lens reference surface s behind the front surface (convex surface a) is applied to the position reference surface 14a of the lens barrel 10, so that the positioning in the optical axis direction and the inclination of the optical axis O are determined. Therefore, accurate and highly accurate optical axis direction positioning and alignment are possible, and surface tilt can be prevented with high accuracy.

  In the present embodiment, the first lens L1 is heat staked along the chamfer f at the front end of the cylindrical portion 22 with the lens reference surface s applied to the position regulating surface 24a of the first group lens frame 20. By doing so, it is fixed to the first group lens frame 20. For this reason, the caulking portion 22a is narrow enough to hold the first lens L1 in the first group lens frame 20 even if the radial width where the caulking portion 22a is in contact with the peripheral portion of the front surface (convex surface a) of the first lens L1 is narrow and the thickness is small. Strength is obtained. Since the radial width of the caulking portion 22a is narrow and thin, it can be used as an optically effective surface up to the outermost periphery of the front surface (convex surface a) of the first lens L1, and even without increasing the outer diameter of the first lens L1, A lens having a larger effective diameter than the maximum diameter can be obtained. In FIG. 5B, an inner flange 22f is formed at the front end of the cylindrical portion 22 ′, and the inner peripheral edge of the inner flange 22f on the first lens L1 side is used as the lens surface (front surface) of the first lens L1. ) Shows a conventional example (Patent Document 2). In this conventional example, the inner flange 22f blocks the light beam. Therefore, if the same effective diameter as that of the first lens L1 of the present embodiment shown in FIG. According to the embodiment, the same effective diameter can be obtained with a small-diameter lens).

  The cylindrical portion 22 of the first group lens frame 20 before the first lens L1 is inserted has a simple cylindrical shape. However, if the outer peripheral surface is tapered (tapered), the caulking operation becomes easy, and the inside of the caulking portion The thickness of the peripheral portion in the optical axis direction is reduced, and wider-angle incident light cannot be squeezed by the caulking portion.

  The second lens L2 is inserted from the rear into the holding cylinder portion 13a. The front end outer peripheral step g of the second lens L2 contacts the position restriction flange 13a1, and the position and inclination of the second lens L2 in the optical axis direction are determined. The second lens L2 has its columnar surface in contact with the inner peripheral surface of the holding cylinder portion 13a, and the position in the direction perpendicular to the optical axis is determined. In this state, an adhesive is put in an adhesive recess (not shown) formed in the holding cylinder part 13a, and the lens barrel 10 (holding cylinder part 13a) and the second lens L2 are fixed. The second lens L2 is preferably fixed to the holding cylinder portion 13a before the first group lens frame 20 is fixed to the lens barrel 10.

  In the above embodiment, the single lens is supported in the cylindrical portion 22 (inner cylindrical surface 21) of the first group lens frame 20. However, the present invention can also be applied to an aspect in which a plurality of lenses are supported with a spacer interposed therebetween. is there.

DESCRIPTION OF SYMBOLS 10 Lens barrel 11 Large cylindrical part 12 Straight guide protrusion 13 Lens support flange 13a Holding cylinder part 13a1 Position regulation flange 13b 13c Free fitting cylinder part 14 Connection wall 14a Position reference surface 14b Recessed recess (recessed part)
15 Support surface 15a 15b Optical axis orthogonal surface 15c Partially conical inner surface 16 Recess for alignment 17 Recess for adhesive 20 Group 1 lens frame (lens frame)
21 Inner cylindrical surface 22 Tubular portion 22a Caulking portion (heat caulking portion)
23 Flange portion 23a 23b Optical axis orthogonal surface 23c Partial conical surface 24 Lens receiving portion 24a Position regulating surface L1 First lens (lens)
s Lens reference plane

Claims (8)

A cylindrical portion into which at least one lens is inserted, and a plurality of circumferentially spaced lenses formed radially inwardly at an end opposite to the lens insertion side end of the cylindrical portion. A lens frame that holds the lens; and a lens barrel into which the lens frame is inserted and fixed;
The lens has a lens reference surface at an end on the lens receiving portion side;
The lens frame has a position regulating surface with which the lens reference surface abuts on the lens insertion side of the lens receiving portion; and the lens barrel is held by the lens frame between the adjacent lens receiving portions. Having a plurality of position reference surfaces in contact with the lens reference surface of the formed lens;
Lens support structure characterized by 2. The lens support structure according to claim 1, wherein a recess for accommodating the lens receiving portion of the lens frame is formed between the plurality of position reference surfaces of the lens barrel. 3. The lens support structure according to claim 1, wherein the lens frame is configured such that the lens inserted into the cylindrical portion is heat squeezed on the position-regulating surface and a lens insertion side end of the cylindrical portion. Lens support structure held between the two parts. 4. The lens support structure according to claim 1, wherein the lens reference surface of the lens held by the lens frame inserted into the lens barrel is in contact with the position reference surface. A lens support structure having a loosely fitting tube portion in which the lens and the lens frame are loosely fitted so as to be freely movable in a direction orthogonal to the optical axis. 5. The lens support structure according to claim 1, wherein the lens barrel includes an alignment recess for holding the lens frame inserted in the lens barrel, and the lens frame. The lens support structure in which the recessed part for adhesive agents for adhere | attaching on a cylinder is formed. 6. The lens support structure according to claim 1, wherein the lens barrel includes a holding cylinder portion that holds a lens different from the lens of the lens frame inserted from the side opposite to the lens insertion side. A lens support structure. 7. The lens support structure according to claim 1, wherein the lens receiving portion of the lens frame is in contact with an image side surface of the at least one lens. 8. The lens support structure according to claim 1, wherein the at least one lens is a lens closest to the object side.

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