JP2012123220A - Lens fixation structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens fixation structure, where a pair of lenses is fixed to the lens frame by caulking with a spacer to adjust a space placed between both lenses, capable of fixing a lens to a lens frame without changing a caulking position.SOLUTION: In a lens fixation structure, a cylindrical lens frame has a caulking section at one end section and a lens position reference surface on an inner circumference thereof. One lens of a pair of lenses has an edge surface opposite to the other lens and a fixation reference surface which abuts on the lens position reference surface. The one lens is fixed to the lens frame by caulking the caulking section of the lens frame in a state where the fixation reference surface abuts on the lens position reference surface. The other lens of the pair of the lenses is positioned by abutting on the one lens through a spacer placed between the one lens and an opposite end surface of the other lens opposite to the one lens.

Description

  The present invention relates to a lens fixing structure in which two sets (two) of lenses are fixed to a lens frame in a state where a spacer (spacer) for adjusting a distance is sandwiched between both lenses.

  Conventionally, a structure in which a spacer (sheet member) is sandwiched between two lenses is known as a fixing structure for fixing two adjacent lenses to a lens frame after adjusting the distance (Patent Document 1). ). In Patent Document 1, one lens (first lens) is inserted into a lens frame, its rear surface is applied to a step portion in the lens frame, and then the other lens (second lens) with a spacer interposed therebetween. Was inserted into the lens frame, and the first and second lenses with the spacer interposed between them were fixed by screwing the presser ring in contact with the front edge portion of the second lens into the front end female thread portion of the lens frame. . In Patent Document 1, workability is poor because there is an operation of screwing the presser ring into the screw portion.

JP 2008-233631 A

  On the other hand, there is a method of caulking and fixing (for example, heat caulking) as a method of easily and surely fixing the lens to the lens frame in a short time. Also in Patent Document 1, this caulking fixing method can be adopted instead of the presser ring that is screwed into the lens frame. However, since Patent Document 1 has a structure in which the first lens, the spacer, and the second lens are stacked in the optical axis direction, if the lens interval is adjusted by the thickness of the spacer, it is caulked due to the difference in the thickness of the spacer. The position will change. If the caulking is fixed while ignoring the change in the caulking position, the caulking cannot be reliably fixed. In order to securely fix by caulking, the caulking position by the caulking device has to be adjusted every time the thickness of the spacer changes, which is rather time consuming.

  The present invention has been made on the basis of the above problem awareness, and a lens fixing structure for fixing two sets of lenses to a lens frame by caulking in a state in which a spacer (spacer) for adjusting a distance is sandwiched between both lenses. The purpose of the present invention is to obtain a lens fixing structure capable of fixing the lens to the lens frame without changing the caulking position.

  The present invention is a lens fixing structure in which two sets of lenses sandwiching a spacer are inserted in a cylindrical lens frame so as to be aligned in the central axis direction of the lens frame, and the lens frame is caulked and fixed. The cylindrical lens frame has a caulking portion at one end portion in the central axis direction of the lens frame, and abuts one of the two sets of lenses on the inner peripheral portion thereof to position the lens position in the central axis direction with respect to the lens frame. A lens position reference surface to be determined; one of the two sets of lenses has an opposing end surface facing the other lens and a fixed reference surface in contact with the lens position reference surface; the one lens is fixed In the state where the reference surface is in contact with the lens position reference surface of the lens frame, the lens frame is fixed to the lens frame by caulking, and the other of the two sets of lenses is: Opposite end face with one lens It is via a spacer which is interposed between the positioning in contact with one of the lens said, is characterized by, that are fixed to the lens frame.

  The lens position reference surface of the lens frame is preferably formed on the same plane orthogonal to the optical axis.

  It is practical to provide the lens frame with a large-diameter portion and a medium-diameter portion that hold the one lens, and to form the lens position reference surface at a step portion between the large-diameter portion and the medium-diameter portion. .

  The lens frame is provided with a small-diameter portion that is smaller than the medium-diameter portion that is continuous with the medium-diameter portion and holds the other lens, and the other lens is inserted into the small-diameter portion, It is preferable to press and hold the lens via a spacer.

  The spacer is, for example, a hollow disk-shaped sheet member having a diameter smaller than the inner diameter of the medium diameter portion and larger than the inner diameter of the small diameter portion, and can be inserted into the medium diameter portion from the large diameter portion. .

  In the lens fixing structure of the present invention, one fixed reference surface and the opposing end surface of the two sets of lenses can be formed in different regions on the same plane.

  The lens frame is provided with a large-diameter portion that holds the one lens and a small-diameter portion that holds the other lens, and the lens position reference surface is formed at a step portion between the large-diameter portion and the small-diameter portion. Is preferred.

  The small-diameter portion preferably has an inner diameter that enables the position adjustment of the other lens in the direction perpendicular to the optical axis.

  According to the present invention, in a lens fixing structure in which two sets of lenses with a spacer interposed between cylindrical lens frames are inserted and the lens frames are caulked and fixed, one lens is a lens of a cylindrical lens frame. Since it is held between the position reference surface and the caulking portion, the caulking position does not change even if the thickness of the spacer is changed. The other lens is positioned via the spacer on the caulking and fixing lens, so that it can be easily positioned and fixed easily.

It is a disassembled perspective view which shows 1st Embodiment of the lens fixing structure by this invention. It is the upper half sectional view which cut the lens fixing structure longitudinally in the plane containing an optical axis in an assembly state. FIG. 5 is a longitudinal half sectional view corresponding to FIG. 2 showing a second embodiment of the lens fixing structure according to the present invention.

  1 and 2 show an embodiment of a lens fixing structure according to the present invention. This lens fixing structure is an embodiment in which the first lens group L in the forefront (subject side) of the photographing lens is held in the first group lens frame 10. The first group lens frame 10 is coupled to another lens frame when mounted on the lens barrel.

  The first lens group L is composed of two (two sets) lenses, a first lens L1 and a second lens L2, which are positioned in order from the subject side, and a spacer (sheet) between the first lens L1 and the second lens L2. Member) 20 is arranged. The front first lens L1 has a larger diameter than the rear second lens L2.

  The first group lens frame 10 made of synthetic resin has a cylindrical cylindrical portion 11, and this cylindrical portion 11 is concentric in order from the tip end on the subject side (front end in the central axis direction, front) to the rear. A lens having a large-diameter portion 12, a medium-diameter portion 13, and a small-diameter portion 14, and a stepped portion between the large-diameter portion 12 and the medium-diameter portion 13 and having a plane orthogonal to the central axis (optical axis O). A position reference surface 15 is formed. This lens position reference surface 15 is a reference position in the optical axis direction of the first lens L1. As shown in FIG. 1, the small diameter portion 14 is discontinuous in the circumferential direction. A thin-walled caulking portion (heat caulking portion) 16 having a sharp tip end is formed at the tip end portion of the large diameter portion 12. In FIG. 2, the shape of the caulking portion 16 before heat caulking is drawn with a chain line.

  A large-diameter first edge surface L1a and a small-diameter second edge surface L1b are formed in order from the front (subject) side on the edge surface (circumferential surface) of the first lens L1. The first edge surface L1a and the second edge surface L1b each have a cylindrical outer peripheral surface shape set to a diameter that can be inserted into the large diameter portion 12 and the medium diameter portion 13, and the first edge surface L1a and the second edge surface L1b. A fixed reference surface L1c having a planar shape perpendicular to the optical axis O is formed at the step portion between the surfaces L1b. This fixed reference plane L1c is a reference position in the optical axis direction of the first lens L1. Further, a planar pressing surface L1d orthogonal to the optical axis O is formed outside the effective optical surface area (annular area along the edge) on the rear surface of the first lens L1. The pressing surface L1d is an end surface facing the second lens L2.

  The large-diameter portion 12 is clamped and fixed to the lens position reference surface 15 by caulking the caulking portion 16 with the fixed reference surface L1c of the first lens L1 applied to the lens position reference surface 15. It is formed to a length that can be made. The length of the medium diameter portion 13 in the optical axis direction is such that when the fixed reference surface L1c is applied to the lens position reference surface 15, the pressing surface L1d and the step portion between the medium diameter portion 13 and the small diameter portion 14 (light It is formed so that a gap can be formed between it and the spacer 20 with sufficient play in the optical axis direction.

  The second lens L2 has a cylindrical outer peripheral surface L2a, and a reference surface L2b and a pressing surface L2c, which are planes orthogonal to the optical axis, are formed outside the effective optical surface area. ing. The reference surface L2b is an end surface facing the first lens L1. The inner diameter of the small diameter portion 14 of the first group lens frame 10 is formed to be slightly larger than the outer diameter of the edge surface L2a, and the length of the small diameter portion 14 in the optical axis direction is the thickness (edge surface) of the edge portion of the second lens L2. It is formed thinner than the length of L2a in the optical axis direction).

  The first lens L1 and the second lens L2 described above are assembled to the first group lens frame 10 (cylindrical portion 11) as follows. It is assumed that the thickness of the spacer 20 interposed between the first lens L1 and the second lens L2 is determined in advance for each lot, for example. First, a spacer 20 having a thickness selected from the front is inserted into the middle diameter portion 13 of the first group lens frame 10. Next, the first lens L1 is inserted into the large-diameter portion 12 from the subject side (front), and the distal end portion of the cylindrical portion 11 is caulked with the fixed reference surface L1c applied to the lens position reference surface 15. The part 16 is caulked (heat caulked). By this caulking, the caulking portion 16 contacts over the entire circumference of the caulking region (chamfered portion) L1e on the front side of the first lens L1, and presses the first lens L1 against the lens position reference surface 15. The solid line in FIG. 2 is the shape after heat caulking.

  Next, the second lens L2 is inserted into the small diameter portion 14 from the rear side of the cylindrical portion 11 so as to be aligned with the first lens L1 in the central axis (optical axis O) direction, and the second lens L2 is interposed via the spacer 20. The reference surface L2b is applied to the pressing surface L1d of the first lens L1. In this state, the lens pressing plate 21 is applied to the second lens L2 and attached to the rear end of the cylindrical portion 11, and the second lens L2 is pressed and held on the first lens L1 via the spacer 20. In this holding state, the second lens L2 is moved in the direction orthogonal to the optical axis O against the frictional resistance between the spacer 20 and the lens pressing plate 21, and the direction orthogonal to the optical axis. Adjust the position of. After the adjustment is completed, an adhesive is injected into the gap between the second lens L2 and the lens pressing plate 21 or the gap between the second lens L2 and the small diameter portion 14 to fix the second lens L2 to the cylindrical portion 11. As the adhesive, a photo-curing type or a thermosetting type can be used.

  In the above embodiment, the lens position reference surface 15 is formed by using the step portions of the large diameter portion 12 and the medium diameter portion 13 having different inner diameters. However, the lens position reference surface 15 is formed from the inner periphery of the cylindrical portion. It is also possible to form it by a flange part, a protrusion, a convex part or the like protruding inward.

  In the above embodiment, the first lens L1 has the first edge surface L1a and the second edge surface L1b having different diameters, and the step between the first edge surface L1a and the second edge surface L1b is formed. Although the fixed reference plane L1c orthogonal to the optical axis O is formed by using the fixed reference plane L1c, the fixed reference plane L1c may be formed in a region that does not contact the spacer 20 on the end surface facing the second lens. Absent.

  FIG. 3 shows a second embodiment of the present invention, in which the fixed reference surface L11c and the opposed end surface (pressing surface) L11d of the first lens L11 are set in different regions on the same plane. That is, in the first lens L11 of the second embodiment, the edge surface (circumferential surface) is formed as an edge surface (cylindrical surface) L11a having no step that can be inserted into the large-diameter portion 112, and its rear surface is effective. The optical axis orthogonal surface outside the optical surface region has a fixed reference surface L11c on its outer side and a pressing surface L11d on its inner side. The fixed reference surface L11c is a reference position in the optical axis direction of the first lens L11, and the pressing surface L11d is an end surface facing the second lens L22.

  The first group lens frame 110 has a cylindrical cylindrical portion 111, and the cylindrical portion 111 includes a concentric large-diameter portion 112 and a small-diameter portion 114, and is provided between the large-diameter portion 112 and the small-diameter portion 114. A lens position reference surface 115 made of a plane orthogonal to the central axis (optical axis O) is formed at the step portion. A thin-walled caulking portion (heat caulking portion) 116 with a sharp tip portion indicated by a chain line is formed over the entire circumference at the tip portion of the large diameter portion 112.

  The large-diameter portion 112 and the caulking portion 116 are formed by caulking the caulking portion 116 with the fixed reference surface L11c of the first lens L11 applied to the lens position reference surface 15, and the lens position reference surface 115. It is formed in a length that can be fixed between.

  The second lens L2 has the same shape as the second lens L2 shown in FIGS. 1 and 2, and has a cylindrical outer surface L2a. Before and after the second lens L2, light is emitted outside the effective optical surface area. A reference surface L2b and a pressing surface L2c, which are planes orthogonal to the axis, are formed. The reference surface L2b is an end surface facing the first lens L11.

  The first lens L11 and the second lens L2 described above are assembled to the first group lens frame 110 (cylindrical portion 111) as follows. It is assumed that the thickness of the spacer 20 interposed between the first lens L11 and the second lens L2 is determined in advance for each lot, for example. The first lens L11 is inserted into the large-diameter portion 112 from the caulking portion 116 side (subject side, front side), and the caulking portion 16 is caulked with the fixed reference surface L11c applied to the lens position reference surface 115 ( Heat staking). By this caulking process, the caulking portion 116 contacts the entire caulking area ((chamfered portion)) L11e on the front side of the first lens L11, and fixes the first lens L11 between the lens position reference surface 115. .

  Next, a spacer 20 of a selected thickness is inserted into the small diameter portion 14 of the first group lens frame 110 from the rear, and then the second lens L2 is inserted and the reference of the second lens L2 is inserted via the spacer 20. The surface L2b is applied to the pressing surface L11d of the first lens L11. In this state, the lens pressing plate 21 is applied to the second lens L2 and attached to the rear end of the cylindrical portion 111, and the second lens L2 is pressed and held on the first lens L11 via the spacer 20. In this state, the same position adjustment as that of the first embodiment shown in FIGS. 1 and 2 is performed, and after the adjustment is completed, the second lens L2 is fixed to the cylindrical portion 111 with an adhesive.

  In the above embodiment, the two lenses (two sets) are both single lenses, but one or both of the two sets of lenses may be a bonded lens.

10 1 group lens frame (lens frame)
DESCRIPTION OF SYMBOLS 11 Cylindrical part 12 Large diameter part 13 Medium diameter part 14 Small diameter part 15 Lens position reference surface 16 Caulking part 17 Optical axis orthogonal surface 20 Spacer 21 Lens pressing plate 111 Cylindrical part 112 Large diameter part 114 Small diameter part 115 Lens position reference Surface 116 Caulking portion L First lens group L1 First lens L1a First edge surface L1b Second edge surface L1c Fixed reference surface L1d Holding surface (opposing end surface)
L1e Caulking region L11 First lens L11a Edge surface L11c Fixed reference surface L11d Pressing surface (opposing end surface)
L11e Caulking region L2 Second lens L2a Edge surface L2b Reference surface L2c Pressing surface (opposing end surface)
O Optical axis (center axis)

Claims (8)

A lens fixing structure in which two sets of lenses sandwiching a spacer are inserted in a cylindrical lens frame so as to be aligned in the central axis direction of the lens frame, and the lens frame is caulked and fixed.
The cylindrical lens frame has a caulking portion at one end in the central axis direction of the lens frame, and a lens position in the central axis direction with respect to the lens frame by contacting one of the two sets of lenses on the inner peripheral portion thereof Having a lens position reference plane to determine
One of the two sets of lenses has a facing end surface that faces the other lens and a fixed reference surface that contacts the lens position reference surface;
The one lens is fixed to the lens frame by caulking the caulking portion of the lens frame in a state where the fixed reference surface is in contact with the lens position reference surface of the lens frame; and The other of the two sets of lenses is positioned in contact with the one lens through a spacer interposed between the lens and the opposite end surface, and is fixed to the lens frame.
Lens fixing structure characterized by   The lens fixing structure according to claim 1, wherein the lens position reference surface is formed on the same plane orthogonal to the optical axis.   3. The lens fixing structure according to claim 1, wherein the lens frame has a large-diameter portion and a medium-diameter portion that hold the one lens, and the step is provided between the large-diameter portion and the medium-diameter portion. A lens fixing structure in which a lens position reference surface is formed.   4. The lens fixing structure according to claim 3, wherein the lens frame includes a small-diameter portion that holds the other lens and has a smaller diameter than the medium-diameter portion that is continuous with the medium-diameter portion, A lens fixing structure inserted into the small-diameter portion and pressed and held by the one lens via a spacer.   5. The lens fixing structure according to claim 4, wherein the spacer is a hollow disk-shaped sheet member having a diameter smaller than an inner diameter of the medium diameter portion and larger than an inner diameter of the small diameter portion. Lens fixing structure inserted in the medium diameter part.   3. The lens fixing structure according to claim 1, wherein one fixed reference surface and the opposite end surface of the two sets of lenses are formed in different regions on the same plane.   7. The lens fixing structure according to claim 6, wherein the lens frame has a large-diameter portion that holds the one lens and a small-diameter portion that holds the other lens, and a step between the large-diameter portion and the small-diameter portion. A lens fixing structure in which the lens position reference surface is formed on the portion.   The lens fixing structure according to any one of claims 4 to 7, wherein the small diameter portion has an inner diameter capable of adjusting a position of the other lens in a direction orthogonal to the optical axis.

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