Lens unit

Abstract

Provided is a lens unit capable of regulating movement of a second lens barrel in the optical axis direction without applying a load on a lens housed in a first lens barrel. A lens unit (1) has: a lens L1; a lens L2 that is disposed on the image side X2 of the lens L1; a first lens barrel (3) that houses the lens L1; and a second lens barrel (4) that houses the lens L2 and is held on the inner circumferential side of the first lens barrel (3). The first lens barrel (3) is provided with a protruding part (102) protruding from an image-side portion to the inner circumferential side. The second lens barrel (4) is provided with: an image-side step part (224) that abuts the protruding part (102) from the object side X1; and a lens barrel fixation part (245) that is in contact with the protruding part (102) from the image side X2 and that sandwiches the protruding part (102) between itself and the image-side step part (224).

Description

Lens unit

[0001] The present invention relates to a lens unit including a first barrel that houses a first lens, and a second barrel that houses a second lens that is arranged on the image side of the first lens on the inner periphery side of the first barrel.

[0002] Such a lens unit is described in Patent Document 1. In this document, the first lens barrel has a step portion in the middle of its inner circumferential surface in the optical axis direction. The step portion has a receiving portion facing the object side and a small diameter portion facing radially inward on the image side of the supported portion. Meanwhile, the second lens barrel (lens holding ring) has a step portion on its outer circumferential surface. The step portion has a supported portion facing the image side and an opposing portion opposing the small diameter portion. The second lens barrel is held on the inner circumferential side of the first lens barrel while being positioned in the optical axis direction, as the supported portion comes into close contact with the receiving portion in the optical axis direction.

[0003] The lens unit also includes a cap attached to the object-side end of the first barrel. The cap has a larger diameter than the first barrel and is fixed to the first barrel by being screwed onto a male thread formed on the object-side end of the first barrel. The cap includes a retaining portion that protrudes inward from the object-side end. When the cap is screwed onto the first barrel, the retaining portion abuts against the outer edge of the first lens from the object side, preventing the first lens from falling off toward the object side. The retaining portion also abuts the second barrel against a receiving portion of the first barrel via the first lens and the lens group housed in the second barrel.

[0004] Japanese Patent Application Laid-Open No. 2019-203907

[0005] In a structure such as that disclosed in Patent Document 1, in which the movement of the second barrel in the optical axis direction is restricted by a pressing portion that contacts the first lens, there is a possibility that a load will be applied to the first lens via the pressing portion.

[0006] In view of the above problems, an object of the present invention is to provide a lens unit that can restrict movement of the second lens barrel in the optical axis direction without placing a load on the lens housed in the first lens barrel.

[0007] In order to solve the above problem, the lens unit of the present invention comprises a first lens, a second lens arranged on the image side of the first lens, a first barrel that houses the first lens, and a second barrel that houses the second lens and is held on the inner side of the first barrel, wherein the first barrel has a protrusion that protrudes from the image side portion toward the inner side, and the second barrel has an object-side abutment that abuts against the protrusion from the object side, and a barrel fixing part that contacts the protrusion from the image side and sandwiches the protrusion between it and the object-side abutment.

[0008] In this invention, the protruding portion of the first lens barrel is sandwiched from both sides in the optical axis direction by the object-side abutment portion and the lens barrel fixing portion provided on the second lens barrel. Therefore, movement of the second lens barrel in the optical axis direction can be restricted without placing a load on the lenses housed in each lens barrel. Furthermore, because the object-side abutment portion of the second lens barrel abuts against the protruding portion of the first lens barrel, the position of the second lens barrel in the optical axis direction relative to the first lens barrel can be determined.

[0009] In the present invention, the lens barrel fixing part can include a first plastically deformed part that bends outwardly and a contact part that contacts the protrusion on the outer periphery of the plastically deformed part. That is, the lens barrel fixing part can be configured such that the first plastically deformed part is formed by crimping a part of the second lens barrel outwardly, and the contact part at the tip of the first plastically deformed part is brought into contact with the protrusion.

[0010] In the present invention, the second lens barrel may include an image-side step portion at an image-side portion of its outer peripheral surface, the image-side step portion having an annular surface facing the image side and an image-side outer peripheral surface portion extending from an inner peripheral end of the annular surface toward the image side, the annular surface being the object-side abutment portion, and an image-side clearance being provided between the image-side outer peripheral surface portion and the protrusion in the radial direction. In this way, when the protrusion of the first lens barrel is sandwiched between the object-side abutment portion and the lens barrel fixing portion provided on the second lens barrel, it is possible to prevent the orientation of the second lens barrel relative to the first lens barrel from being determined as a state in which the second lens barrel abuts against the inner peripheral end face of the protrusion.

[0011] In the present invention, the first lens barrel has an object-side facing portion that faces the object-side end portion of the second lens barrel from the outside in the radial direction, and an object-side clearance is provided between the object-side facing portion and a facing surface portion of the outer peripheral surface of the second lens barrel that faces the object-side facing portion in the radial direction, and the position of the object-side end portion of the second lens barrel in the radial direction is defined within the range of the object-side clearance, and the position of the image-side outer peripheral surface portion in the radial direction is defined within the range of the image-side clearance. In this way, the orientation of the second lens barrel relative to the first lens barrel can be defined within the range of the object-side clearance and the image-side clearance. Furthermore, because there is an object-side clearance and an image-side clearance between the first lens barrel and the second lens barrel, even if the second lens barrel expands due to heat or moisture absorption, the effects of this expansion can be absorbed by these clearances.

[0012] In the present invention, an inter-lens adhesive layer may be provided between a flange surface located on the outer periphery of the image-side lens surface of the first lens and a flange portion located on the outer periphery of the object-side lens surface of the second lens, the inter-lens adhesive layer sealing the space formed between the image-side lens surface and the object-side lens surface from the outer periphery, and the inter-lens adhesive layer may be elastic. This can prevent or suppress the intrusion of water vapor and the like from the outside into the space formed between the image-side lens surface and the object-side lens surface in the optical axis direction. Furthermore, if the inter-lens adhesive layer is elastic, even if the second lens barrel expands due to heat or moisture absorption and causes a slight displacement of the second lens, the inter-lens adhesive layer deforms in response to the displacement, thereby maintaining the sealing of the space communicating between the first image-side lens surface and the second object-side lens surface.

[0013] In the present invention, the second lens barrel may include an optical element holding portion that holds the optical element at the image-side end portion, the optical element holding portion including an optical element mounting surface on which the optical element is placed from the image side, and an optical element facing portion that faces the optical element placed on the optical element mounting surface from the image side, the optical element facing portion including a second plastically deformed portion that bends toward the inner periphery and a facing portion that faces the optical element on the inner periphery of the plastically deformed portion. This configuration can mechanically prevent the optical element held at the image-side end portion of the second lens barrel from falling off toward the image side. Furthermore, the optical element facing portion may be formed by caulking a portion of the second lens barrel toward the inner periphery, with the facing portion of the tip facing the optical element.

[0014] In the present invention, the lens barrel fixing portion and the optical member facing portion can be made visible when viewed from the image side, and by doing so, a caulking punch can be pressed against the lens barrel fixing portion fixing portion and the optical member facing portion from the image side of the second lens barrel to provide them.

[0015] In the present invention, the first plastically deformed portion and the second plastically deformed portion can be at the same height in the optical axis direction along the optical axis, and the protrusion-side contact surface of the protrusion with which the contact portion of the barrel fixing portion contacts can be located closer to the image than the optical element-side facing surface with which the facing portion of the optical element-facing portion faces. Since the first plastically deformed portion and the second plastically deformed portion are at the same height, the barrel fixing portion and the optical element-facing portion can be simultaneously formed using a crimping punch with a flat punch surface. Furthermore, the protrusion-side contact surface of the protrusion with which the contact portion of the barrel fixing portion contacts is located closer to the image than the optical element-side facing surface with which the facing portion of the optical element-facing portion faces. Therefore, when the barrel fixing portion and the optical element-facing portion are simultaneously formed using a crimping punch with a flat punch surface, the facing portion of the optical element-facing portion can be pressed against the optical element-side facing surface, preventing or suppressing damage to the optical element.

[0016] In the present invention, the lens barrel fixing portions may be provided at two locations on either side of the optical member, and the optical member opposing portions may be provided at two locations on either side of the optical member, at positions different from the lens barrel fixing portions.

[0017] In the present invention, the lens barrel fixing portion may extend from the second lens barrel toward the outer periphery and be welded to the protruding portion. That is, the lens barrel fixing portion may be formed by melting a portion of the second lens barrel, extending it toward the first lens barrel, and welding it to the protruding portion.

[0018] In the lens unit of the present invention, the protruding portion of the first lens barrel is sandwiched from both sides in the optical axis direction by the object-side abutment portion and the lens barrel fixing portion provided on the second lens barrel. Therefore, movement of the second lens barrel in the optical axis direction can be restricted without placing a load on the lenses housed in each lens barrel. Furthermore, because the object-side abutment portion of the second lens barrel abuts against the protruding portion of the first lens barrel, the position of the second lens barrel in the optical axis direction relative to the first lens barrel can be determined.

[0019] 1 is an external perspective view of the lens unit when viewed from the object side; FIG. 2 is an external perspective view of the lens unit when viewed from the image side; FIG. 3 is a cross-sectional view of the lens unit; FIG. 4 is an exploded perspective view of the lens unit; FIG. 5 is a cross-sectional view of the first lens barrel; FIG. 6 is a cross-sectional view of the second unit; FIG. 7 is a perspective view of the second lens barrel when viewed from the object side; FIG. 8 is a perspective view of the lens unit in the middle of assembly when viewed from the image side; FIG. 9 is a partially enlarged cross-sectional view of the vicinity of the optical member opposing portion; FIG. 10 is a perspective view of a modified lens unit when viewed from the image side.

[0020] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a lens unit to which the present invention is applied will be described with reference to the drawings.

[0021] (Overall Configuration) Fig. 1 is a perspective view of the appearance of a lens unit to which the present invention is applied, as viewed from the object side. Fig. 2 is a perspective view of the lens unit, as viewed from the image side. Fig. 3 is a cross-sectional view of the lens unit. In Fig. 3, the shapes of each lens in the area between two dashed double-dashed lines (around the optical axis) are omitted.

[0022] The lens unit 1 shown in FIG. 1 is used in an imaging device mounted on an automobile or a surveillance camera. As shown in FIG. 3, the lens unit 1 includes, from the object side to the image side, a lens L1 (first lens), a lens L2 (second lens), a lens L3 (third lens), a lens L4 (fourth lens), a lens L5 (fifth lens), and a lens L6 (sixth lens), in this order. The lens L6 is a cemented lens, and includes, from the object side to the image side, an object-side lens L61 and an image-side lens L62, in this order. The lens unit 1 also includes a lens barrel 2, which includes a first lens barrel 3 and a second lens barrel 4 held on the inner periphery of the first lens barrel 3. The lens L1 is housed in the first lens barrel 3. The lenses L2 to L6 are housed in the second lens barrel 4. The lens L1 has a larger outer diameter than the lenses L2 to L6.

[0023] As shown in Fig. 1, lens L1 and first lens barrel 3 constitute a first unit 50. As shown in Fig. 4, lenses L2 to L6 and second lens barrel 4 constitute a second unit 60. In the following description, the direction along the optical axis L of lens L1 is referred to as the optical axis direction X. The optical axis L of lens L1 is the optical axis L of lens unit 1. The object side X1 in the optical axis direction X is the side where lens L1 is located, and the image side X2 is the side where lens L6 is located.

[0024] (Optical System) As shown in Figures 1 and 3, the lens L1 is a meniscus lens having a convex shape on the object side X1. As shown in Figure 3, the lens L1 has an annular flange surface 11 that extends in a direction perpendicular to the optical axis L on the outer periphery of the image-side lens surface L1a. A first O-ring 7 is disposed on the image side X2 of the flange surface 11 of the lens L1. The lens L1 is made of glass or resin. In this example, it is made of glass.

[0025] The lens L2 includes a lens body 13 having a lens surface, and a flange 14 surrounding the lens body 13. The lens body 13 is a meniscus lens having a convex shape on the object side X1. The object-side lens surface L2a of the lens L2 protrudes toward the object side X1. An annular protrusion 15 protruding toward the object side X1 is provided on the end face of the flange 14 on the object side X1. The annular protrusion 15 includes, at its tip, an annular opposing surface 15a that faces the flange surface 11 of the lens L1 in the optical axis direction X. An inter-lens adhesive layer 12 is interposed between the flange surface 11 of the lens L1 and the opposing surface 15a of the second lens. The inter-lens adhesive layer 12 is elastic.

[0026] The lens L3 includes a lens body 16 having a lens surface and a flange 17 surrounding the lens body 16. The lens body 16 is a meniscus lens having a convex shape on the image side X2. An annular fitting portion 18 that protrudes toward the object side X1 is provided on the end surface of the flange 17 on the image side X2. The fitting portion 18 surrounds the optical axis L and includes a fitting portion tapered surface 18a that slopes inward toward the image side X2, and a fitting portion end surface 18b that extends perpendicular to the optical axis L from the end of the fitting portion tapered surface 18a on the image side X2 toward the inner periphery.

[0027] An elastic member is disposed between the lens L2 and the lens L3 in the optical axis direction X. The elastic member is a second O-ring 8. The second O-ring 8 is compressed in the optical axis direction X between the flange portion 14 of the lens L2 and the flange portion 17 of the lens L3.

[0028] The lens L4 includes a lens body 20 having a lens surface and a flange 21 surrounding the lens body 20. The lens surface on the object side X1 of the lens body 20 of the lens L4 is a curved surface that protrudes toward the object side X1. The lens surface on the image side X2 of the lens body 20 includes a curved surface portion at its center that protrudes toward the image side X2. The end surface on the object side X1 of the flange 21 is provided with a fitted portion 22 into which the fitting portion 18 of the lens L3 fits. The fitted portion 22 surrounds the optical axis L and includes a fitted portion tapered surface 22a that slopes inward toward the image side X2, and a fitted portion end surface 22b that extends perpendicular to the optical axis L from the end of the image side X2 of the fitted portion tapered surface 22a toward the inner periphery. The fitted portion tapered surface 18a of the lens L3 and the fitted portion tapered surface 22a of the lens L4 are in surface contact. The fitting portion end face 18b of lens L3 and the fitted portion end face 22b of lens L4 are spaced apart in the optical axis direction X. This positions lens L3 in the radial direction relative to lens L4. Furthermore, the image-side end face X2 of the outer peripheral portion of fitting portion 18 of flange portion 17 of lens L3 and the object-side end face X1 of the outer peripheral portion of fitted portion 22 of flange portion 21 of lens L4 come into contact in the optical axis direction X. Therefore, lens L3 is stacked on lens L4 in the optical axis direction X.

[0029] Lens L5 has a smaller outer diameter than lenses L2, L3, L4, and L6. Lens L5 includes a lens body 24 having a lens surface and a flange 25 surrounding the lens body 24. The lens body 24 is a biconvex lens. The image side X2 of the flange 25 is a contact portion 26 that contacts lens L6 from the object side X1. A cross section of the contact portion 26 cut along the optical axis L is an arc that curves toward the object side X1 toward the outer periphery. The image side X2 surface of the contact portion 26 is continuous without a step with the outer periphery edge of the lens surface 24a of the image side X2 of the lens body 24.

[0030] A resin holder 28 is disposed radially outward of lens L5. Holder 28 is annular. An aperture 33 is disposed between lens L4 and lens L5. The aperture 33 is an annular sheet and is sandwiched between lens L4 and holder 28.

[0031] The object-side lens L61 includes a lens body 35 having a lens surface and a flange 36 surrounding the lens body 35. The lens surface on the object side X1 of the object-side lens L61 is a curved surface that curves toward the image side X2, and the lens surface on the image side X2 is a curved surface that is recessed toward the object side X1. The flange 36 of the object-side lens L61 includes a contacted portion 37 on the object side X1 with which the contact portion 26 of the lens L5 comes into contact. The contacted portion 37 is a tapered surface that extends toward the object side X1 toward the outer periphery. The contact portion 26 and the contacted portion 37 are in line contact. The flange 36 of the object-side lens L61 includes an annular end face 38 on the image side X2 that is perpendicular to the optical axis L.

[0032] The image-side lens L62 includes a lens body 40 having a lens surface and a flange 41 surrounding the lens body 40. The lens surface on the object side X1 of the image-side lens L62 is a curved surface that protrudes toward the object side X1, and the lens surface on the image side X2 is a curved surface that protrudes toward the object side X1. The image-side lens L62 is fixed to the object-side lens L61. The outer diameter of the image-side lens L62 is smaller than the outer diameter of the object-side lens L61. Therefore, when viewed from the image side X2, the flange 36 of the object-side lens L61 includes a portion that protrudes outward from the image-side lens L62.

[0033] Here, the lenses L2, L3, L4, the object-side lens L61, and the image-side lens L62 are all made of resin. In this example, the lenses L2, L3, L4, the object-side lens L61, and the image-side lens L62 are all made of amorphous plastic. The amorphous plastic is, for example, polycarbonate. The lens L5 is made of glass.

[0034] Furthermore, lens L5 is stacked on lens L6. Lens L4 is stacked on lens L6 via holder 28. Lens L6, lens L5, holder 28, and lens L4 constitute a stacked body 44. Lens L3 is stacked on lens L4 in a state where it is positioned in the radial direction by fitting into lens L4. Lens L2 is held by the second lens barrel 4 on the object side X1 of lens L3.

[0035] Next, a plate-shaped optical member 10 is disposed on the image side X2 of the lens L6. The optical member 10 is a band-pass filter. In this example, the optical member 10 is an IR cut filter. As shown in FIG. 2 , the optical member 10 has a rectangular shape when viewed from the optical axis direction.

[0036] (Lens barrel) Fig. 4 is an exploded perspective view of lens unit 1. Fig. 5 is a cross-sectional view of the first lens barrel. As shown in Fig. 3, lens unit 1 includes a lens barrel 2 made of a first lens barrel 3 and a second lens barrel 4 held on the inner periphery of first lens barrel 3. Both first lens barrel 3 and second lens barrel 4 are made of resin. Lens L1 is housed in first lens barrel 3. Lenses L2 to L6 and holder 28 are housed in second lens barrel 4. Second lens barrel 4 is held on the inner periphery of first lens barrel 3.

[0037] (First Lens Barrel and Lens L1) As shown in Fig. 4, the first lens barrel 3 has a cylindrical shape. The first lens barrel 3 is located on the outer periphery of lenses L2, L3, L4, holder 28, lenses L5, L6, and the second lens barrel 4. As shown in Fig. 5, the first lens barrel 3 has an object-side step 101 at the end portion on the object side X1 of its inner circumferential surface. The first lens barrel 3 also has an annular protrusion 102 at the end portion on the image side X2. The first lens barrel 3 also has an intermediate step 103 between the object-side step 101 and the protrusion 102 on its inner circumferential surface.

[0038] The object-side step 101 includes a support surface 105 facing the object side X1, an annular wall surface 106 extending from the inner peripheral edge of the support surface 105 toward the image side X2, and a peripheral wall surface 107 extending from the outer peripheral edge of the support surface 105 toward the object side X1. In the first lens barrel 3, the object side X1 of the object-side step 101 is a first lens housing portion 108 that houses the outer peripheral edge portion of the lens L1. The second lens barrel 4 is disposed on the inner peripheral side of the annular wall surface 106.

[0039] The first lens housing 108 includes a peripheral wall surface 107, a support surface 105, and a crimped portion 109. As shown in FIG. 3 , the peripheral wall surface 107 faces the lens L1 from the radially outer side. The support surface 105 faces the flange surface 11 of the lens L1 from the image side X2. The crimped portion 109 abuts the lens L1 from the object side X1 at a position overlapping with the support surface 105 when viewed from the optical axis direction X along the optical axis L of the lens L1. The crimped portion 109 is a plastically deformed portion formed by, for example, thermal crimping, bending the end of the first lens barrel 3 on the object side X1 toward the inner periphery. Here, the outer peripheral edge portion of the lens L1 is disposed between the support surface 105 and the crimped portion 109. The first O-ring 7 is disposed between the end face of the lens L1 on the image side X2 and the support surface 105, and is compressed in the optical axis direction X.

[0040] 4 and 5 , object-side protrusions 110 that protrude radially inward are provided at multiple locations around the circumference of the annular wall surface 106. In this example, the object-side protrusions 110 are provided at three locations around the circumference, equiangularly spaced apart. The object-side protrusions 110 are object-side facing portions that face the object-side end portion (positioning surface 223, described later) of the second lens barrel 4 from the radial outside in order to position the second lens barrel 4 in the radial direction.

[0041] As shown in Fig. 5 , the protrusion 102 includes an annular object-side annular surface 111 facing the object side X1, an image-side annular surface 112 facing the image side X2, and an inner peripheral end surface 113 extending in the optical axis direction X and connecting an inner peripheral end of the object-side annular surface 111 with an inner peripheral end of the image-side annular surface 112. As shown in Fig. 4 , the object-side annular surface 111 is provided with a plurality of ribs 114 that protrude toward the object side X1 and extend in an arc shape in the circumferential direction. In this example, the ribs 114 are provided at three positions in the circumferential direction at equal angular intervals.

[0042] Here, the rib 114 is an image-side positioning portion for positioning the second lens barrel 4 in the optical axis direction X. The inner peripheral end face 113 is an image-side facing portion that faces the image-side portion of the second lens barrel 4 (an image-side outer peripheral surface portion 227, described later) from the outside in the radial direction in order to position the second lens barrel 4 in the radial direction. As shown in FIG. 2 , the image-side annular surface 112 of the protrusion 102 is located closer to the object side X1 than the end face 115 of the first lens barrel 3 on the image side X2. The image-side annular surface 112 is provided with four circumferentially extending arc ribs 119 at four locations spaced apart in the circumferential direction.

[0043] As shown in FIG. 5 , the intermediate step portion 103 includes an annular step flange surface 116 facing the object side X1 and an annular step wall surface 117 extending from the inner circumferential end of the step flange surface 116 toward the image side X2. In this example, the intermediate step portion 103 is provided with notched grooves 118 at multiple locations around the circumference, extending in the optical axis direction X and dividing the step flange surface 116 and the step wall surface 117 in the circumferential direction. The notched grooves 118 are provided at three locations around the circumference, equiangularly spaced. Therefore, the intermediate step portion 103 is divided into three parts around the circumference by the notched grooves 118. The bottom surface of the notched groove 118 is the annular wall surface 106 extending from the inner circumferential end of the support surface 105 toward the image side X2, and the portion where the intermediate step portion 103 is provided has a tapered shape in which the inner diameter dimension decreases toward the image side X2. The annular wall surface 106 reaches the outer peripheral end of the object-side annular surface 111 of the protrusion 102 on the inner peripheral surface of the first lens barrel 3 .

[0044] Here, when the second lens barrel 4 is held by the first lens barrel 3, there is no contact between the first lens barrel 3 and the second lens barrel 4 in the radial direction between the object-side protrusion 110 and the protrusion 102 in the optical axis direction X. In other words, there is a gap in the radial direction between the object-side protrusion 110 and the protrusion 102 in the optical axis direction X. There is no contact between the first lens barrel 3 and the second lens barrel 4 in the radial direction on the object side X1 of the object-side protrusion 110 or on the image side X2 of the protrusion 102.

[0045] Next, as shown in Fig. 5, the first lens barrel 3 has three steps 121, 122, and 123 on the object side of its outer circumferential surface, the outer diameter of which decreases in a stepped manner toward the image side X2. Furthermore, these steps have male threads 124 on the image side X2. However, the shape of the outer circumferential surface of the first lens barrel 3 is not limited to this. For example, the outer circumferential surface of the first lens barrel 3 may be integrally provided with an outer frame for mounting the lens unit 1 on an external device.

[0046] (Second Lens Barrel, Lenses L2 to L6, and Optical Members) FIG. 6 is a cross-sectional view of the second unit 60. The cross-section of FIG. 6 cuts the second unit 60 at an angle 90° different from that of FIG. 3 around the axis L. FIG. 7 is a perspective view of the second lens barrel 4 as seen from the object side X1. FIG. 8 is a perspective view of the lens unit 1 in the middle of assembly as seen from the image side X2. FIG. 9 is a partially enlarged cross-sectional view of the vicinity of the optical member holding portion 204. As shown in FIG. 6, the second lens barrel 4 houses lenses L2, L3, L4, L5, holder 28, and lens L6 on its inner periphery. The second lens barrel 4 also holds an optical member 10 at its end on the image side X2.

[0047] The second lens barrel 4 has an object-side step 201 at the end portion of the inner circumferential surface on the object side X1. The second lens barrel 4 also has an image-side protrusion 202 that protrudes inward at the end portion of the image side X2. The second lens barrel 4 also has a positioning step 203 on the inner circumferential surface between the object-side step 201 and the image-side protrusion 202, and at a position closer to the image-side protrusion 202 than the object-side step 201. The second lens barrel 4 also has an optical element holder 204 that holds the optical element 10 on the image side X2 of the image-side protrusion 202.

[0048] The object-side step 201 includes a seating surface 205 facing the object side X1, an annular wall surface 206 extending from the inner peripheral edge of the seating surface 205 toward the image side X2, and a peripheral wall surface 207 extending from the outer peripheral edge of the seating surface 205 toward the object side X1. The annular wall surface 206 is a tapered surface whose inner diameter decreases toward the image side X2. In the second lens barrel 4, the object side X1 of the object-side step 201 is a second lens housing portion 208 that houses the outer peripheral edge portion of the lens L2.

[0049] The second lens housing portion 208 includes a peripheral wall surface 207, a seating surface 205, and a crimped portion 209. The peripheral wall surface 207 is a tapered surface that slopes from the seating surface 205 toward the outer periphery toward the object side X1. As shown in FIG. 7 , the peripheral wall surface 207 includes engagement protrusions 210A at multiple circumferentially spaced locations that are press-fitted to the lens L2. In this example, the engagement protrusions 210A are provided at six circumferentially spaced locations at equal angular intervals. The engagement protrusions 210A include, at their inner peripheral ends, pressure-fitting surfaces 210a that are parallel to the optical axis L. The pressure-fitting surfaces 210a of the multiple engagement protrusions 210A press-fitted to the lens L2 housed in the second lens housing portion 208 from the radially outer side, thereby positioning the lens L2 in the radial direction. The seating surface 205 faces the image-side X2 end surface of the flange portion 14 of the lens L2 from the image side X2. The crimped portion 209 abuts against the lens L2 from the object side X1 at a position that overlaps with the seating surface 205 when viewed from the optical axis direction X. The crimped portion 209 is a plastically deformed portion provided by, for example, thermal crimping, which bends the end of the second lens barrel 4 on the object side X1 toward the inner periphery. Here, as shown in Figure 6, the annular protrusion 15 provided on the flange portion 14 of the lens L2 protrudes further toward the object side X1 than the crimped portion 209 on the inner periphery side of the crimped portion 209.

[0050] The annular wall surface 206 of the object-side step 201 extends toward the image side X2 and reaches the positioning step 203. As shown in FIG. 7 , the annular wall surface 206 is provided with an engaging protrusion 210B, an engaging protrusion 210C, an engaging protrusion 210D, and a guide protrusion 220, in this order, at a predetermined interval, from the image side X2 toward the object side X1. The engaging protrusions 210B to 210D and the guide protrusion 220 each protrude toward the inner periphery from multiple locations spaced apart in the circumferential direction. The engaging protrusions 210B to 210D each have a pressure-contact surface parallel to the optical axis L at their inner periphery ends. The guide protrusion 220 has a guide surface parallel to the optical axis L at its inner periphery end.

[0051] As shown in Fig. 6, the positioning step 203 is located in the image-side portion of the inner periphery of the second lens barrel 4. The positioning step 203 includes an annular step positioning surface 215 facing the object side X1, and a step peripheral wall surface 216 extending from the inner periphery end of the step positioning surface 215 to the image side X2. The annular wall surface 206 of the object-side step 201 extends to the image side X2 and reaches the outer periphery end of the step positioning surface 215. As shown in Fig. 7, the step positioning surface 215 is provided with a plurality of positioning ribs 217 that protrude toward the object side X1 and extend in an arc shape in the circumferential direction.

[0052] As shown in FIG. 6 , the flange portion 36 of the object-side lens L61 of the lens L6 is placed on the positioning rib 217. As a result, the laminate 44 consisting of the lens L6, the lens L5, the holder 28, and the lens L4 is housed in the second lens barrel 4 while being positioned in the optical axis direction X. In addition, the fitting protrusions 210B, 210C, and 210D provided on the annular wall surface 206 are pressed against the lens L6, the holder 28, and the lens L4 from the radially outer side, respectively. This positions the laminate 44 in the radial direction. The image-side lens L62 of the lens L6 cemented to the object-side lens L61 is disposed on the inner circumferential side of the stepped peripheral wall surface 216. The stepped peripheral wall surface 216 faces the image-side lens L62 with a gap therebetween in the radial direction.

[0053] 3, the lens L3 is positioned in the radial direction by its fitting portion 18 fitting into the fitted portion 22 of the lens L4. Furthermore, the lens L3 is positioned in the optical axis direction X by being stacked on the lens L4. The guide protrusion 220 is a member for guiding the lens L3 toward the lens L4, and when the lens L3 is positioned in the radial direction by the lens L4, the guide protrusion 220 and the lens L3 face each other with a gap in the radial direction.

[0054] The second O-ring 8 is disposed on the object side X1 of the plurality of guide protrusions 220, radially inward of the annular wall surface 206 of the object-side step portion 201. As shown in Fig. 6 , the second O-ring 8 is compressed in the optical axis direction X between the lens L2 and the lens L3 housed in the second lens housing portion 208.

[0055] Next, the second lens barrel 4 has an annular positioning surface 223 at the object-side end X1 of its outer circumferential surface. The positioning surface 223 is located radially outward of the second lens housing portion 208. The positioning surface 223 is parallel to the optical axis L and faces radially outward. When the second lens barrel 4 is housed on the inner circumferential side of the first lens barrel 3, the object-side protrusion 110 (object-side facing portion) of the first lens barrel 3 faces the positioning surface 223. As shown in FIG. 3 , an object-side clearance C1 is provided between the object-side protrusion 110 and the positioning surface 223.

[0056] 6 , the second lens barrel 4 includes an image-side step 224 on the image-side portion of its outer circumferential surface. The image-side step 224 includes an annular surface 225 facing the image side X2, an object-side outer circumferential surface portion 226 extending from the outer circumferential end of the annular surface 225 toward the object side X1, and an image-side outer circumferential surface portion 227 extending from the outer circumferential end of the annular surface 225 toward the image side X2. The image-side outer circumferential surface portion 227 is connected to the outer circumferential end of the image-side annular end face 213 of the second lens barrel 4. The outer circumferential surface of the second lens barrel 4 also includes an intermediate step 228 located between the positioning surface 223 and the image-side step 224 and close to the positioning surface 223. The intermediate step 228 includes an annular surface 229 facing the image side X2. The object-side outer circumferential surface portion 226 of the image-side step 224 reaches the inner circumferential end of the annular surface 229. The image-side step 224 (annular surface 229) is an object-side contact portion that contacts the protrusion 102 of the first lens barrel 3 from the object side X1.

[0057] As shown in FIG. 3 , when the second lens barrel 4 is housed inside the first lens barrel 3, the image-side step 224 rests on the multiple ribs 114 of the protruding portion 102 of the first lens barrel 3. The image-side outer peripheral surface portion 227 faces the inner peripheral end face 113 (image-side facing portion) of the protruding portion 102 of the first lens barrel 3. An image-side clearance C2 is provided between the inner peripheral end face 113 and the image-side outer peripheral surface portion 227. The image-side clearance C2 is larger than the object-side clearance C1. The image-side clearance C2 is 10 μm or more and 15 μm or less on one side of the optical axis L.

[0058] As shown in FIG. 2 , the optical element holder 204 is provided on the image-side annular end surface 213 of the second lens barrel 4. The optical element holder 204 includes an optical element mounting surface 231 (see FIG. 3 ) that surrounds the center hole of the second lens barrel 4 in the central portion of the image-side annular end surface 213, and four guide ribs 232 that surround the image-side annular end surface 213 on all sides. The four guide ribs 232 include two sets of pairs of guide ribs 232 that face each other across the center hole of the second lens barrel 4. The optical element holder 204 also includes an optical element facing portion 233 that extends inward from the image-side X2 end surface of one set of the pair of guide ribs 232 (1) and faces the optical element 10 placed on the optical element mounting surface 231 from the image side X2. The optical element facing portion 233 includes a plastically deformed portion 234 (second plastically deformed portion) that bends from the image-side X2 end face of the guide rib 232 toward the inner periphery, and a facing portion 235 that faces the optical element 10 on the inner periphery side of the plastically deformed portion 234. The facing portion 235 faces the outer periphery of the optical element 10.

[0059] As shown in FIG. 8 , the optical element facing portion 233 is formed by crimping an optical element fixing caulking margin 241 provided on the image-side end surface X2 of one pair of guide ribs 232(1) toward the inner periphery to form a plastically deformed portion 234, with the tip facing portion 235 facing the optical element 10. A gap is provided between the facing portion 235 and the optical element 10 in the optical axis direction X. While held by the optical element holding portion 204, the optical element 10 is fixed to the second lens barrel 4 with adhesive applied to its outer periphery. While held by the optical element holding portion 204, the four corners of the optical element 10 protrude from the second lens barrel 4 at their tip portions toward the outer periphery and overlap the protrusions 102 of the first lens barrel 3 when viewed from the optical axis direction X. Here, the image-side annular surface 112 of the protrusions 102 is located closer to the object side X1 than the optical element 10. Therefore, the optical element 10 does not come into contact with the first lens barrel 3.

[0060] (Lens barrel fixing portion) Here, as shown in Fig. 2, of the four guide ribs 232 surrounding the image-side annular end face 213 on all sides, the other pair of guide ribs 232(2) is provided with a lens barrel fixing portion 245 for fixing the first lens barrel 3 and the second lens barrel 4. The lens barrel fixing portion 245 contacts the protruding portion of the first lens barrel 3 from the image side X2 when the second lens barrel 4 is housed on the inner peripheral side of the first lens barrel 3. As shown in Figs. 2 and 3, the lens barrel fixing portion 245 includes a plastically deformed portion 246 (first plastically deformed portion) that bends toward the outer peripheral side of the image-side X2 end face of the guide rib 232, and a contact portion 247 that contacts the protruding portion on the outer peripheral side of the plastically deformed portion 246. As shown in FIG. 8, the lens barrel fixing portion 245 is formed by crimping the lens barrel fixing crimping allowance 242 provided on the end face on the image side X2 of the other pair of guide ribs 232(2) toward the inner periphery to form a plastically deformed portion 246, and the opposing portion 235 at the tip of the crimping allowance 242 faces the optical element 10.

[0061] Here, when the lens unit 1 is viewed from the image side X2, the lens barrel fixing portion 245 and the optical member facing portion 233 are visible. Furthermore, in the optical axis direction X along the optical axis L, the plastically deformed portion 234 of the optical member facing portion 233 and the plastically deformed portion 246 of the lens barrel fixing portion 245 are at the same height. The lens barrel fixing portions 245 are provided in two locations on both sides of the optical member 10, and the optical member facing portions 233 are provided in two locations on both sides of the optical member 10, but at positions different from the lens barrel fixing portions 245.

[0062] (Fixing the First and Second Lens Barrels) When fixing the first and second lens barrels 3 and 4 together, first, lenses L2 to L6 are held by the second lens barrel 4. In this state, the optical element 10 is not held by the optical element holder 204 of the second lens barrel 4. Also, in this state, as shown in FIG. 8 , the pair of optical element fixing caulking margins 241 and the pair of lens barrel fixing caulking margins 242 provided at the end of the second lens barrel 4 on the image side X2 are not caulked.

[0063] Next, the second lens barrel 4 is held by the first lens barrel 3. That is, the second lens barrel 4 is inserted into the inner periphery of the first lens barrel 3 from the object side X1. When inserting the second lens barrel 4 into the first lens barrel 3, first, the image-side outer peripheral surface portion 227 of the image-side step 224 of the second lens barrel 4 is inserted into the inner periphery of the protrusion 102 of the first lens barrel 3. Next, the annular surface 225 of the image-side step 224 of the second lens barrel 4 is placed on the multiple ribs 114 of the protrusion 102 of the first lens barrel 3. In parallel with this, the object-side end portion (positioning surface 223) of the second lens barrel 4 is inserted into the inner periphery of the object-side step 101 of the first lens barrel 3.

[0064] 3 , an image-side clearance C2 is provided between the inner peripheral end surface 113 (image-side facing portion) of the protrusion 102 of the first lens barrel 3, which is used to position the first lens barrel 3 and the second lens barrel 4 in the radial direction, and the image-side outer peripheral surface portion 227 of the image-side step 224 of the second lens barrel 4. Also, an object-side clearance C1 is provided between the object-side protrusion 110 (object-side facing portion) provided on the annular wall surface 106 of the object-side step 101 of the first lens barrel 3, which is used to position the first lens barrel 3 and the second lens barrel 4 in the radial direction, and the positioning surface 223 of the object-side end portion of the second lens barrel 4. Furthermore, the image-side clearance C2 is larger than the object-side clearance C1. That is, when the second lens barrel 4 is inserted into the first lens barrel 3 from the object side X1, the image-side clearance C2 between the image-side outer peripheral surface portion 227 of the image-side step portion 224 of the second lens barrel 4, which is inserted first, is larger than the object-side clearance C1 between the positioning surface 223 of the second lens barrel 4, which is inserted later, and the object-side protrusion 110 of the first lens barrel 3. Therefore, it is easy to insert the second lens barrel 4 into the first lens barrel 3.

[0065] An image-side clearance C2 is provided between the inner peripheral end surface 113 (image-side facing portion) of the protrusion 102 of the first lens barrel 3 and the image-side outer peripheral surface portion 227 of the image-side step 224 of the second lens barrel 4. An object-side clearance C1 is provided between the object-side protrusion 110 (object-side facing portion) provided on the annular wall surface 106 of the object-side step 101 of the first lens barrel 3 and the positioning surface 223 of the object-side end portion of the second lens barrel 4. Furthermore, the first lens barrel 3 and the second lens barrel 4 have a radial gap between the object-side protrusion 110 (object-side facing portion) and the protrusion 102 in the optical axis direction X. Therefore, the second lens barrel 4 is positioned on the first lens barrel 3 with very little play, rather than being perfectly positioned in all radial directions.

[0066] Next, the first lens barrel 3 and the second lens barrel 4 are gripped with a jig and positioned so that the object side X1 faces downward (see FIG. 8 ). Then, the optical element 10 is placed on the optical element holding portion 204 of the second lens barrel 4. Here, the image-side annular surface 112 of the protruding portion 102 of the first lens barrel 3 is positioned closer to the object side X1 than the optical element placement surface 231 of the second lens barrel 4. Therefore, the corners of the optical element 10 protruding outward from the second lens barrel 4 do not come into contact with the first lens barrel 3.

[0067] Thereafter, a crimping punch having a flat punch surface is brought into contact with the first lens barrel 3 and the second lens barrel 4 from above (the image side X2) to crimp a pair of optical member fixing crimping prongs 241 and a pair of lens barrel fixing crimping prongs 242 provided at the end of the second lens barrel 4 on the image side X2. Here, as shown in FIG. 8 , the pair of optical member fixing crimping prongs 241 have inclined surfaces 241a on the side opposite the optical axis L that slope outward from the tip toward the guide rib 232. Therefore, by the crimping punch approaching the second lens barrel 4 from the optical axis direction X, the pair of optical member fixing crimping prongs 241 form optical member facing portions 233 that include plastically deformed portions 234 that bend inward and facing portions 235 that face the optical member 10 on the inner side of the plastically deformed portions 234. Furthermore, the surfaces of the pair of barrel fixing caulking margins 242 located on the optical axis L side are inclined surfaces 242a that slope inward from the tips toward the guide rib 232. Therefore, the caulking punch forms the pair of barrel fixing caulking margins 242 into barrel fixing parts 245 that include plastically deformed parts 246 that bend outward and contact parts 247 that come into contact with the protrusion 102 on the outer periphery side of the plastically deformed parts 246.

[0068] 9 , a height H1 between the optical element mounting surface 231 and the end face of the guide rib 232 on the image side X2 is longer than a thickness D1 of the optical element 10. In addition, the end face 119a (protrusion-side contact surface) of the arc rib 119 is located closer to the image side X2 than the image side surface 10a (optical element-side facing surface) of the optical element 10, which faces the facing portion 235 of the optical element facing portion 233. Therefore, when a pair of optical element fixing crimping tabs 241 and a pair of lens barrel fixing crimping tabs 242 are crimped with a crimping punch having a flat punch surface, the lens barrel fixing crimping tabs 242 are plastically deformed toward the outer periphery, and the contact portion 247 at their tip comes into contact with the end face 119a of the arc rib 119 of the first lens barrel 3, but a gap is provided in the optical axis direction X between the opposing portion 235 at the tip of the optical element fixing crimping tab 241, which has been plastically deformed toward the inner periphery, and the optical element 10.

[0069] Once the crimping is complete, the second lens barrel 4 sandwiches the protrusion 102 of the first lens barrel 3 between the annular surface 225 of the image-side step 224 and the lens barrel fixing portion 245. Therefore, the second lens barrel 4 is fixed to the first lens barrel 3. Furthermore, the optical element 10 is mechanically prevented from falling off the second lens barrel 4 to the image side X2 by the optical element facing portion 233. After that, adhesive is applied to the outer periphery of the optical element 10. As a result, the optical element 10 is fixed to the optical element holding portion 204.

[0070] Thereafter, the first lens barrel 3 and the second lens barrel 4 are inverted. An adhesive is applied to the opposing surface 15a of the flange portion 14 of the lens L2 held by the second lens barrel 4. The first O-ring 7 is placed on the support surface 105 of the first lens barrel 3. The lens L1 is then supported on the support surface 105 of the first lens barrel 3 via the first O-ring 7. A crimped portion 109 is then formed at the object-side X1 end portion of the first lens barrel 3, bending inward. Once the crimped portion 109 is formed, the first O-ring 7 is compressed in the optical axis direction X between the image-side X2 end face of the lens L1 and the support surface 105 of the first lens barrel 3. The cured adhesive, the inter-lens adhesive layer 12, seals the space V between the image-side lens surface L1a of the lens L1 and the object-side lens surface L2a of the lens L2 on the outer periphery in the optical axis direction X. The inter-lens adhesive layer 12 is elastic.

[0071] (Effects) The lens unit 1 of this example includes a lens L1, a lens L2 located on the image side X2 of the lens L1, a first lens barrel 3 housing the lens L1, and a second lens barrel 4 housing the lens L2 and held on the inner periphery of the first lens barrel 3. The first lens barrel 3 includes a protrusion 102 that protrudes inward from the image side. The second lens barrel 4 includes an image side step 224 that abuts against the protrusion 102 from the object side X1, and a lens barrel fixing portion 245 that contacts the protrusion 102 from the image side X2 and sandwiches the protrusion 102 between the image side step 224 and the first lens barrel 3. This prevents the second lens barrel 4 from moving in the optical axis direction X without applying a load to the lenses housed in each lens barrel. Furthermore, because the image side step 224 of the second lens barrel 4 abuts against the protrusion 102 of the first lens barrel 3, the position of the second lens barrel 4 in the optical axis direction X relative to the first lens barrel 3 can be determined.

[0072] Here, barrel fixing portion 245 includes plastically deformed portion 246 that bends outward, and contact portion 247 that comes into contact with protrusion 102 on the outer periphery of plastically deformed portion 246. Therefore, barrel fixing portion 245 can be configured such that plastically deformed portion 246 is formed by crimping a portion of second barrel 4 outward, and contact portion 247 at the tip of plastically deformed portion 246 comes into contact with protrusion 102.

[0073] In this example, the second lens barrel 4 includes an image-side step 224 on the image side of its outer peripheral surface. The image-side step 224 has an annular surface 225 facing the image side X2 and an image-side outer peripheral surface portion 227 (image-side facing portion) extending from the inner peripheral end of the annular end surface toward the image side X2. The annular surface 225 abuts against the protrusion 102 from the object side. In the radial direction, an image-side clearance C2 is provided between the image-side outer peripheral surface portion 227 and the inner peripheral end face 113 of the protrusion 102. Therefore, when the protrusion 102 of the first lens barrel 3 is sandwiched between the image-side step 224 and the lens barrel fixing portion 245 provided on the second lens barrel 4, the orientation of the second lens barrel 4 relative to the first lens barrel 3 can be prevented from being determined as an orientation in which the second lens barrel 4 abuts against the inner peripheral end face 113 of the protrusion 102.

[0074] Furthermore, in this example, the first lens barrel 3 has an object-side protrusion 110 (object-side facing portion) that faces the object-side end portion X1 of the second lens barrel 4 from the outside in the radial direction. An object-side clearance C1 is provided between the object-side protrusion 110 and a positioning surface 223 (facing surface portion) on the outer peripheral surface of the second lens barrel 4 that faces the object-side protrusion 110 in the radial direction. The position of the object-side X1 end portion of the second lens barrel 4 in the radial direction is defined within the range of the object-side clearance C1, and the position of the image-side end portion in the radial direction is defined within the range of the image-side clearance C2. Therefore, the attitude of the second lens barrel 4 relative to the first lens barrel 3 can be defined within the range of the object-side clearance C1 and the image-side clearance C2.

[0075] That is, the second lens barrel 4 is positioned radially between a state in which a portion of the outer periphery of the object-side X1 end portion contacts the object-side protrusion 110 of the first lens barrel 3 and a state in which the object-side X1 end portion does not contact the object-side protrusion 110 over the entire circumference, with a gap of object-side clearance C1. Therefore, any radial wobble of the object-side X1 end portion of the second lens barrel 4 is only that of the object-side clearance C1 and is very slight. Furthermore, the image-side X2 end portion of the second lens barrel 4 is positioned within the range of image-side clearance C2 on the inner periphery side of the first lens barrel 3. That is, the second lens barrel 4 is positioned between a state in which a portion of the outer periphery of the image-side X2 end portion contacts the image-side outer peripheral surface portion 227 of the first lens barrel 3 and a state in which the image-side X2 end portion does not contact the image-side outer peripheral surface portion 227 over the entire circumference, with a gap of image-side clearance C2. Therefore, the wobble in the radial direction of the end portion of the second lens barrel 4 on the image side X2 is only the wobble of the image side clearance C2, which is very slight.

[0076] Furthermore, the second tube portion is positioned at two locations spaced apart in the optical axis direction X between the object-side end portion X1 and the image-side portion. Therefore, tilt of the optical axis of the lens L2 held in the second tube 4 relative to the optical axis L of the lens L1 held in the first tube 3 is suppressed. Furthermore, the object-side clearance C1 between the object-side end portion X1 of the second tube 4 closest to the lens L1 and the first tube 3 is smaller than the image-side clearance C2 between the image-side portion of the second tube 4 and the first tube 3. This suppresses wobble on the object side X1 more than on the image side X2. Therefore, it is possible to suppress a large misalignment between the optical axis L of the lens L1 held in the first tube 3 and the optical axis of the lens L2 held in the second tube 4.

[0077] Furthermore, because there is an object-side clearance C1 and an image-side clearance C2 between the first and second barrels 3 and 4, even if the second barrel 4 expands due to heat or moisture absorption, the effects of this expansion can be absorbed by these clearances C1 and C2. That is, according to this example, the second barrel 4 is positioned to the first barrel 3 with some play, rather than being perfectly positioned in all radial directions. Therefore, even if the amount of deformation of the first and second barrels 3 and 4 due to heat or moisture absorption differs due to differences in shape, thickness, or base material between the first and second barrels 3 and 4, this difference in deformation amount can be absorbed by the play (the object-side clearance C1 and the image-side clearance C2). This prevents or reduces the load applied from the first barrel 3 to the second barrel 4 and the load applied from the second barrel 4 to the first barrel 3 when the first and second barrels deform due to heat or moisture absorption.

[0078] In this example, an inter-lens adhesive layer 12 is provided between the outer peripheral portion (flange portion 14) of the image-side lens surface L1a of the lens L1 and the outer peripheral portion (opposing surface 15a) of the object-side lens surface L2a of the lens L2. The inter-lens adhesive layer 12 seals the space V formed between the image-side lens surface 1a of the lens L1 and the object-side lens surface L2a of the lens L2 from the outer peripheral side. The inter-lens adhesive layer 12 is elastic. Therefore, it is possible to prevent or suppress the intrusion of water vapor and the like from the outside into the space V formed between the image-side lens surface 1a of the lens L1 and the object-side lens surface L2a of the lens L2 in the optical axis direction X. Here, if the inter-lens adhesive layer 12 is elastic, even if the second lens barrel 4 expands due to heat and causes slight displacement of the lens L2, the inter-lens adhesive layer 12 deforms to follow the displacement, thereby maintaining the sealing of the space V.

[0079] Next, this example has a plate-shaped optical element 10. The second lens barrel 4 has an optical element holding portion 204 that holds the optical element 10 at an end portion on the image side X2. The optical element holding portion 204 has an optical element mounting surface 231 on which the optical element 10 is placed from the image side X2, and an optical element facing portion 233 that faces the optical element 10 placed on the optical element mounting surface 231 from the image side X2. Therefore, the optical element 10 held at the end portion on the image side X2 of the second lens barrel 4 can be mechanically prevented from falling off in the optical axis direction X.

[0080] In this example, the optical member facing portion 233 includes a plastically deformed portion 234 that is bent toward the inner periphery, and a facing portion 235 that faces the optical member 10 on the inner periphery side of the plastically deformed portion 234. Therefore, the optical member facing portion 233 can be formed by caulking a portion of the second lens barrel 4 toward the inner periphery, with the plastically deformed portion 234 having the facing portion 235 at its tip facing the optical member 10.

[0081] In this example, when the lens unit 1 is viewed from the image side X2, the barrel fixing portion 245 and the optical member facing portion 233 are visible. Therefore, a caulking punch can be pressed against the second barrel 4 from the image side X2 to provide the fixing portion of the barrel fixing portion 245 and the optical member facing portion 233.

[0082] In this example, the plastically deformed portion 246 of the barrel fixing portion 245 and the plastically deformed portion 234 of the optical element facing portion 233 are at the same height in the optical axis direction X along the optical axis L. Therefore, the barrel fixing portion 245 and the optical element facing portion 233 can be formed at the same time using a crimping punch with a flat punch surface. Furthermore, the protrusion-side contact surface of the protrusion 102 (the end surface 119a of the arc rib 119) with which the contact portion 247 of the barrel fixing portion 245 comes into contact is located closer to the image side X2 than the optical element-side facing surface (the image side X2 surface of the optical element 10) with which the facing portion 235 of the optical element facing portion 233 faces. Therefore, when the barrel fixing portion 245 and the optical element facing portion 233 are formed at the same time, the facing portion 235 of the optical element facing portion 233 is pressed against the image side X2 surface of the optical element 10, which would otherwise damage the optical element 10.

[0083] 10 is a perspective view of a lens unit of a modified example as viewed from the image side. As shown in Fig. 10, in the lens unit 1A of this example, the lens barrel fixing part 245 extends from the second lens barrel 4 to the outer periphery and is welded to the protrusion 102.

[0084] In this case, of the four guide ribs 232 surrounding the image-side annular end face 213 on all sides, the other pair of guide ribs 232(2) that is not provided with the caulking allowance 241 for fixing an optical member is provided with a second-barrel-side welding allowance that protrudes in the optical axis direction X. Also, a first-barrel-side welding allowance that protrudes toward the image side X2 is provided on the image-side end face X2 of the arc rib 119 provided on the image-side annular surface 112 of the protrusion 102 of the first barrel 3. When fixing the first barrel 3 and the second barrel 4 together, first, the second barrel 4 is inserted into the first barrel 3, and the image-side step 224 of the second barrel 4 is placed on the multiple ribs 114 of the protrusion 102 of the first barrel 3. Thereafter, the welding margin of the second lens barrel 4 is melted to the outer periphery by heat from the image side X2 of the first lens barrel 3 and the second lens barrel 4, and welded to the welding margin on the first lens barrel side of the first lens barrel 3.

[0085] Even in this configuration, the second lens barrel 4 includes an image-side step 224 that abuts against the protrusion 102 from the object side X1, and a lens barrel fixing portion 245 that contacts the protrusion 102 from the image side X2. The image-side step 224 and lens barrel fixing portion 245 provided on the second lens barrel 4 sandwich the protrusion 102 of the first lens barrel 3 from both sides in the optical axis direction X, so that movement of the second lens barrel 4 in the optical axis direction X can be restricted without applying load to the lenses housed in each lens barrel. Furthermore, because the image-side step 224 of the second lens barrel 4 abuts against the protrusion 102 of the first lens barrel 3, the position of the second lens barrel 4 in the optical axis direction X relative to the first lens barrel 3 can be defined.

[0086] Here, the present technology can be configured as follows: (1) A lens unit including a first lens, a second lens arranged on the image side of the first lens, a first barrel that houses the first lens, and a second barrel that houses the second lens and is held on the inner circumferential side of the first barrel, wherein the first barrel has a protruding portion that protrudes from an image side portion toward the inner circumferential side, and the second barrel has an object-side abutting portion that abuts against the protruding portion from the object side, and a barrel fixing portion that contacts the protruding portion from the image side and sandwiches the protruding portion between the object-side abutting portion and the first barrel fixing portion.

[0087] (2) The lens unit described in (1) is characterized in that the barrel fixing portion has a first plastic deformation portion that bends toward the outer periphery and a contact portion that contacts the protrusion on the outer periphery of the plastic deformation portion.

[0088] (3) The lens unit described in (2) is characterized in that the second lens barrel has an image-side step portion at the image-side portion of its outer peripheral surface, the image-side step portion having an annular surface facing the image side and an image-side outer peripheral surface portion extending from the inner peripheral end of the annular surface toward the image side, the annular surface being the object-side abutment portion, and an image-side clearance being provided between the image-side outer peripheral surface portion and the protrusion in the radial direction.

[0089] (4) The lens unit described in (3) is characterized in that the first lens barrel has an object-side facing portion that faces the object-side end portion of the second lens barrel from the outside in the radial direction, an object-side clearance is provided between the object-side facing portion and a facing surface portion on the outer surface of the second lens barrel that faces the object-side facing portion in the radial direction, and the object-side clearance, and the position of the object-side end portion of the second lens barrel in the radial direction is defined within the range of the object-side clearance, and the position of the image-side outer surface portion in the radial direction is defined within the range of the image-side clearance.

[0090] (5) A lens unit described in any one of (1) to (4), characterized in that an inter-lens adhesive layer is provided between a flange surface located on the outer periphery of the image-side lens surface of the first lens and a flange portion located on the outer periphery of the object-side lens surface of the second lens, the inter-lens adhesive layer seals the space formed between the image-side lens surface and the object-side lens surface from the outer periphery, and the inter-lens adhesive layer has elasticity.

[0091] (6) A lens unit described in any one of (3) to (4), characterized in that it has a plate-shaped optical element, and the two barrels have an optical element holding portion that holds the optical element at the end portion on the image side, the optical element holding portion having an optical element mounting surface on which the optical element is mounted from the image side, and an optical element facing portion that faces the optical element mounted on the optical element mounting surface from the image side, and the optical element facing portion has a second plastically deformed portion that bends toward the inner circumference, and a facing portion that faces the optical element on the inner circumference side of the plastically deformed portion.

[0092] (7) The lens unit according to (6), characterized in that the lens barrel fixing portion and the optical member facing portion are visible when viewed from the image side.

[0093] (8) A lens unit as described in (6) or (7), characterized in that in the optical axis direction along the optical axis, the first plastic deformation portion and the second plastic deformation portion are at the same height position, and the protrusion-side contact surface of the protrusion with which the contact portion of the lens barrel fixing portion contacts is located closer to the image side than the optical element-side opposing surface with which the opposing portion of the optical element opposing portion faces.

[0094] (9) A lens unit described in any of (6) to (8), characterized in that the barrel fixing portions are provided at two locations on both sides of the optical element, and the optical element facing portions are provided at two locations on both sides of the optical element, at positions different from the barrel fixing portions.

[0095] (10) A lens unit according to any one of (6) to (9), characterized in that the barrel fixing portion extends from the second barrel toward the outer periphery and is welded to the protruding portion.

[0096] DESCRIPTION OF SYMBOLS 1, 1A...lens unit of this example, 2...lens barrel, 3...first lens barrel, 4...second lens barrel, 7...first O-ring, 8...second O-ring, 10...optical member, 10a...image side surface, 11...flange surface, 12...inter-lens adhesive layer, 13...lens main body portion, 14...flange portion, 15...annular protrusion, 15a...opposing surface, 16...lens main body portion, 17...flange portion, 18...fitting portion, 18a...fitting portion tapered surface, 18b...fitting portion end surface, 20...lens main body portion, 21...flange portion, 22...fitted portion, 22a...fitted portion tapered surface, 22b...fitted portion end surface, 24...lens main body portion, 24a...lens surface, 25...f Langge portion, 26...contact portion, 28...holder, 35...lens main body portion, 36...flange portion, 37...contacted portion, 38...annular end surface, 40...lens main body portion, 41...flange portion, 44...laminated body, 50...first unit, 60...second unit, 101...object side step portion, 102...protrusion portion, 103...intermediate step portion, 105...support surface, 106...annular wall surface, 107...circumferential wall surface, 108...first lens housing portion, 109...crimped portion, 110...object side protrusion, 111...object side annular surface, 112...image side annular surface, 113...image side inner wall surface, 114...rib, 115...end surface, 116...step flange surface, 117...step wall surface, 118...notched groove, 119...arc rib, 119a...end surface, 121, 122, 123...step portion, 124...male thread, 201...object side step portion, 202...image side protrusion portion, 203...positioning step portion, 204...optical element holding portion, 205...bearing surface, 206...annular wall surface, 207...circumferential wall surface, 208...second lens housing portion, 209...caulking portion, 210a...pressure-bonding surface, 210A to 210D...engaging protrusions, 213...image side annular end surface, 215...step portion positioning surface, 216...step portion peripheral wall surface, 217...positioning rib, 220...guide protrusion, 223...positioning surface, 224...image side step portion, 225...annular surface, 226...object side Outer circumferential surface portion, 227...image side outer circumferential surface portion, 228...intermediate step portion, 229...annular surface, 231...optical member mounting portion, 232...guide rib, 233...optical member facing portion, 234...plastically deformed portion (second plastically deformed portion), 235...facing portion, 241...caulking allowance for fixing optical member, 241a...inclined surface, 242...caulking allowance for fixing lens barrel, 242a...inclined surface, 245...lens barrel fixing portion, 246...plastically deformed portion (first plastically deformed portion), 247...contact portion, 250...inter-lens barrel adhesive layer, C1...object side clearance, C2...image side clearance, D1...thickness dimension of optical member, H1...height dimension of guide rib,L1 to L6... lenses, L1a... image-side lens surface, L2a... object-side lens surface, L61... object-side lens, L62... image-side lens, V... space, X... optical axis direction,

Claims

1. A lens unit comprising: a first lens; a second lens arranged on the image side of the first lens; a first barrel housing the first lens; and a second barrel housing the second lens and held on the inner periphery of the first barrel, wherein the first barrel has a protrusion protruding from an image side portion to the inner periphery, and the second barrel has an object-side abutment portion that abuts against the protrusion from the object side, and a barrel fixing portion that contacts the protrusion from the image side and sandwiches the protrusion between the object-side abutment portion and the first barrel.

2. The lens unit according to claim 1, characterized in that the lens barrel fixing portion comprises a first plastically deforming portion that is bent toward the outer periphery, and a contact portion that contacts the protrusion on the outer periphery side of the plastically deforming portion.

3. The lens unit described in claim 2, characterized in that the second lens barrel is provided with an image side step portion at the image side portion of its outer peripheral surface, the image side portion having an annular surface facing the image side and an image side outer peripheral surface portion extending from the inner peripheral end of the annular surface to the image side, the annular surface being the object side abutment portion, and an image side clearance being provided between the image side outer peripheral surface portion and the protrusion in the radial direction.

4. The lens unit described in claim 3, characterized in that the first lens barrel has an object-side facing portion that faces the object-side end portion of the second lens barrel from the outside in the radial direction, an object-side clearance is provided between an opposing surface portion of the outer peripheral surface of the second lens barrel that faces the object-side facing portion in the radial direction and the object-side facing portion, and the position of the object-side end portion of the second lens barrel in the radial direction is defined within the range of the object-side clearance, and the position of the image-side outer peripheral surface portion in the radial direction is defined within the range of the image-side clearance.

5. The lens unit described in claim 1, characterized in that an inter-lens adhesive layer is provided between a flange surface located on the outer periphery of the image-side lens surface of the first lens and a flange portion located on the outer periphery of the object-side lens surface of the second lens, the inter-lens adhesive layer seals the space formed between the image-side lens surface and the object-side lens surface from the outer periphery side, and the inter-lens adhesive layer has elasticity.

6. A lens unit as described in claim 2, further comprising a plate-shaped optical member, the second barrel having an optical member holding portion for holding the optical member at the end portion on the image side, the optical member holding portion having an optical member mounting surface on which the optical member is placed from the image side, and an optical member facing portion facing the optical member placed on the optical member mounting surface from the image side, the optical member facing portion having a second plastically deformed portion bent toward the inner circumference, and a facing portion facing the optical member on the inner circumference side of the plastically deformed portion.

7. The lens unit according to claim 6, wherein the lens barrel fixing portion and the optical member facing portion are visible when viewed from the image side.

8. The lens unit described in claim 7, characterized in that in the optical axis direction along the optical axis, the first plastic deformation portion and the second plastic deformation portion are at the same height position, and the protrusion side contact surface of the protrusion with which the contact portion of the lens barrel fixing portion contacts is located on the image side of the optical element side opposing surface with which the opposing portion of the optical element opposing portion faces.

9. The lens unit described in claim 6, characterized in that the lens barrel fixing portions are provided at two locations on both sides of the optical member, and the optical member facing portions are provided at two locations on both sides of the optical member, at positions different from the lens barrel fixing portions.

10. The lens unit according to claim 1, wherein said lens barrel fixing portion extends from said second lens barrel toward the outer periphery and is welded to said protruding portion.

Images