Lens unit and camera module

Abstract

This lens unit includes a first lens disposed on a subject side, and a second lens disposed on an imaging surface side. The first lens and the second lens are disposed in a direction of an optical axis. The first lens and the second lens are in contact with each other at least at three or more locations and are in contact with each other outside optically effective regions of the lenses. In the lens unit, a cross section of a portion where at least one of the first lens and the second lens contacts the other of the first lens and the second lens, the cross section being taken along a plane including the optical axis and the portion, has a convex shape toward the other lens.

Description

Lens unit and camera module

[0001] The present disclosure relates to a lens unit and a camera module.

[0002] In the lens unit described in Patent Document 1, a sixth lens element, which is located closest to the image, and a fifth lens element, which is located closest to the object, are housed in a lens barrel in a state of contact with each other. The sixth lens element is a cemented lens element. The fifth lens element is press-fitted into the center hole of an annular holder.

[0003] The sixth lens has an annular protrusion on the outer periphery of the lens surface facing the object. The annular protrusion has a tip surface at its tip that is perpendicular to the optical axis. The lens barrel contacts the sixth lens from the radially outer side. This positions the sixth lens in the radial direction. Furthermore, an annular support surface provided on the inner periphery of the lens barrel abuts the sixth lens from the image side. This positions the sixth lens in the optical axis direction.

[0004] The fifth lens includes a lens body having a lens surface and a flange surrounding the lens body from the outer periphery. The flange has an annular vertical surface on the image side that is perpendicular to the optical axis. The fifth lens is positioned in the radial direction via the holder when the inner peripheral surface of the lens barrel contacts the holder from the radial outside. The fifth lens is placed on the sixth lens, and the tip surface of the annular protrusion of the sixth lens comes into surface contact with the vertical surface, thereby positioning the fifth lens in the optical axis direction.

[0005] Japanese Patent Application Laid-Open No. 2021-005022

[0006] In the above lens unit, the fifth lens is positioned radially via a holder, and therefore the accuracy of the positioning of the holder within the lens barrel affects the accuracy of the alignment of the sixth lens and the fifth lens.

[0007] The technology of the present disclosure has been developed in consideration of the above facts, and aims to provide a lens unit and a camera module that can align two adjacent lenses simply by bringing the two lenses into contact.

[0008] In order to achieve the above-mentioned object, a first aspect of the technology of the present disclosure is a lens unit comprising a first lens arranged on the subject side and a second lens arranged on the imaging surface side, the first lens and the second lens being arranged in the direction of the optical axis, the first lens and the second lens being in contact with each other in at least three locations and outside the optically effective area of ​​the lenses, wherein a cross section of a portion where at least one of the first lens and the second lens is in contact with the other in a plane including the optical axis and the portion has a convex shape toward the other.

[0009] A second aspect is a camera module including the lens unit of the first aspect.

[0010] According to the technology of the present disclosure, the centering of two adjacent lenses can be performed simply by bringing the two lenses into contact with each other.

[0011] 1 is a perspective view of the appearance of a lens unit to which the technology of the present disclosure is applied. FIG. 2 is a cross-sectional view of the lens unit. FIG. 3 is an exploded perspective view of the lens unit. FIG. 4 is an exploded perspective view of lenses L3 and L4 as viewed from the object side. FIG. 5 is an exploded perspective view of lenses L3 and L4 as viewed from the image side. FIG. 6 is an exploded perspective view of lenses L5 and L6 as viewed from the object side. FIG. 7 is an exploded perspective view of lenses L5 and L6 as viewed from the image side. FIG. 8 is a perspective view of a holder, lens L5, and lens L6. FIG. 9 is a cross-sectional view of a first lens barrel. FIG. 10 is a perspective view of a second lens barrel as viewed from the object side. FIG. 11 is a cross-sectional view of the second lens barrel. FIG. 12 is a cross-sectional view of lens L5 and object-side lens L61. FIG. 13 is a cross-sectional view of lens L5 and object-side lens L61 in a modified example. FIG. 14 is a view showing how lens L5 and object-side lens L61 come into contact at three locations and also outside the optically effective areas of the lenses. FIG. 15 is a view showing how lens L5 and object-side lens L61 come into contact at three locations and also outside the optically effective areas of the lenses in a modified example. 1 is a diagram showing a contact portion 37N12 of the object-side lens L61 in a further modified example. It is a diagram showing a state in which a portion 24H on the object-side lens L61 side in the effective area of ​​the lens L5 is positioned closer to the image side X2 than a contact portion 37N1 of the object-side lens L61 that contacts the lens L5. It is a partial cross-sectional view showing an example in which a cross section of a contact portion where the object-side lens L61 is in contact with the lens L5 in an embodiment, taken on a plane including the optical axis and the contact portion, has a convex shape (curved shape (arcuate shape)) toward the lens L5. It is a partial cross-sectional view showing an example in which a cross section of a contact portion where the object-side lens L61 is in contact with the lens L5 in a plane including the optical axis and the contact portion, has a convex shape (curved shape (elliptical arc shape)) toward the lens L5 in a first modified example. It is a partial cross-sectional view showing an example in which a cross section of a contact portion where the object-side lens L61 is in contact with the lens L5, taken on a plane including the optical axis and the contact portion, has a convex shape (curved shape (shape in which the curvature of the curved line changes)) toward the lens L5. This is a partial cross-sectional view showing an example in which the cross section of the contact portion where the object-side lens L61 comes into contact with the lens L5, in a plane including the optical axis and the contact portion, has an angular shape protruding toward the lens L5 (the intersection angle of the two sides forming the corner in the angular shape is an acute angle).1 is a partial cross-sectional view showing an example of a contact portion where the object-side lens L61 and the lens L5 are in contact, the cross section of which, in a plane including the optical axis and the contact portion, is an angular shape protruding toward the lens L5 (the intersection angle of the two sides forming the angle in the angular shape is an obtuse angle). FIG. 2 is a partial cross-sectional view showing an example of a contact portion where the lens L5 and the object-side lens L61 are in contact, the cross section of which, in a plane including the optical axis and the contact portion, is an angular shape protruding toward the object-side lens L61 (the intersection angle of the two sides forming the angle in the angular shape is an acute angle). FIG. 3 is a partial cross-sectional view showing an example of a contact portion where the lens L5 and the object-side lens L61 are in contact, the cross section of which, in a plane including the optical axis and the contact portion, is an angular shape protruding toward the object-side lens L61 (the intersection angle of the two sides forming the angle in the angular shape is an acute angle). FIG. 4 is a partial cross-sectional view showing an example of a contact portion where the lens L5 and the object-side lens L61 are in contact, the cross section of which, in a plane including the optical axis and the contact portion, is a convex shape (curved shape (shape in which the curvature of the curved line changes)) toward the object-side lens L61. 1 is a partial cross-sectional view showing an example in which a cross section of a contact portion where the lens L5 is in contact with the object-side lens L61, taken on a plane including the optical axis and the contact portion, has a convex shape (curved shape (elliptical arc shape)) toward the object-side lens L61. FIG. 2 is a partial cross-sectional view showing an example in which a cross section of a contact portion where the lens L5 is in contact with the object-side lens L61, taken on a plane including the optical axis and the contact portion, has a convex shape (curved shape (arc shape)) toward the object-side lens L61. FIG. 3 is a partial cross-sectional view showing an example in which a cross section of a contact portion where the lens L5 is in contact with the object-side lens L61, taken on a plane including the optical axis and the contact portion, has an angular shape protruding toward the object-side lens L61 (the intersection angle of two sides forming the corner in the angular shape is an obtuse angle), and a cross section of a portion where the object-side lens L61 is in contact with the lens L5, taken on a plane including the optical axis and the portion, has a convex shape (curved shape (arc shape)) toward the lens L5. This is a partial cross-sectional view showing an example in which the cross section of the contact portion where lens L5 comes into contact with object-side lens L61 in a plane including the optical axis and the contact portion has an angular shape that protrudes toward the object-side lens L61 (the intersection angle of the two sides that form the corner in the angular shape is an acute angle), and the cross section of the contact portion where object-side lens L61 comes into contact with lens L5 in a plane including the optical axis and the contact portion has a convex shape (curved shape (elliptical arc shape)) toward lens L5.1 is a partial cross-sectional view showing an example in which a cross section of a contact portion where the lens L5 is in contact with the object-side lens L61, taken on a plane including the optical axis and the contact portion, has a convex shape (curved shape (shape with a changing curvature of the curved line)) toward the object-side lens L61, and a cross section of a contact portion where the object-side lens L61 is in contact with the lens L5, taken on a plane including the optical axis and the contact portion, has a convex shape (curved shape (shape with a changing curvature of the curved line)) toward the lens L5. FIG. 1 is a partial cross-sectional view showing an example in which a cross section of a contact portion where the lens L5 is in contact with the object-side lens L61, taken on a plane including the optical axis and the contact portion, has a convex shape (curved shape (elliptical arc shape)) toward the object-side lens L61, and a cross section of a contact portion where the object-side lens L61 is in contact with the lens L5, taken on a plane including the optical axis and the contact portion, has an angular shape protruding toward the lens L5 (the intersection angle of two sides forming the corner in the angular shape is an acute angle). 1 is a partial cross-sectional view showing an example in which a cross section of a contact portion where the lens L5 is in contact with the object-side lens L61, taken along a plane including the optical axis and the contact portion, has a convex shape (curved shape (arcuate shape)) toward the object-side lens L61, and a cross section of a contact portion where the object-side lens L61 is in contact with the lens L5, taken along a plane including the optical axis and the contact portion, has an angular shape protruding toward the lens L5 (the intersection angle of two sides forming the angle in the angular shape is an obtuse angle).

[0012] [Embodiments] (Configuration) Hereinafter, an embodiment of a lens unit according to the technology of the present disclosure will be described with reference to the drawings. (Optical System) Fig. 1 is an external perspective view of a lens unit to which the technology of the present disclosure is applied. Fig. 2 is a cross-sectional view of the lens unit. Fig. 3 is an exploded perspective view of the lens unit. Fig. 4 is an exploded perspective view of lenses L3 and L4 as viewed from the object side. Fig. 5 is an exploded perspective view of lenses L3 and L4 as viewed from the image side. Fig. 6 is an exploded perspective view of lenses L5 and L6 as viewed from the object side. Fig. 7 is an exploded perspective view of lenses L5 and L6 as viewed from the image side. Fig. 8 is a perspective view of a holder, lens L5, and lens L6. Note that in Fig. 2, the shapes of the lenses in the area between the two dashed double-dashed lines (around the optical axis) are omitted.

[0013] The lens unit 1 of this example shown in FIG. 1 is used in an imaging device mounted on an automobile or a surveillance camera. As shown in FIG. 2, the lens unit 1 includes, from the object side to the image side, a lens L1, a lens L2, a lens L3, a lens L4, a lens L5, and a lens L6, 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 second lens barrel 4 is held on the inner periphery of the first lens barrel 3.

[0014] As shown in Fig. 3, lens L1 and first lens barrel 3 constitute a first unit 50. Lenses L2 to L6 and second lens barrel 4 constitute a second unit 60. Hereinafter, the direction along the optical axis L of lens L1 will be 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.

[0015] As shown in Figure 2, lens L1 has a larger outer diameter than lenses L2 to L6. In this example, lens L1 is made of glass. Lens L1 is a meniscus lens with a convex shape on the object side X1. Lens L1 has an annular end face 11 that expands in a direction perpendicular to the optical axis L on the outer periphery of the lens surface on the image side X2. A first O-ring 7 is disposed on the image side X2 of end face 11 of lens L1.

[0016] Lens L2 is made of resin. Lens L2 includes a lens body 13 with a lens surface and a flange 14 surrounding the lens body 13. Lens L2 is a meniscus lens with a convex shape on the object side X1. An annular protrusion 15 that protrudes toward the object side X1 is provided on the end face of the flange 14 on the object side X1. The tip of the annular protrusion 15 is an annular contact portion 15a that comes into surface contact with the end face of lens L1.

[0017] As shown in Figures 2, 4, and 5, the lens L3 is made of resin. The lens L3 includes a lens body 16 having a lens surface and a flange 17 surrounding the lens body 16. The lens L3 is a meniscus lens having a convex shape on the image side X2. As shown in Figure 5, an annular fitting portion 18 that protrudes toward the image side X2 is provided on the end surface of the flange 17 facing the image side X2. The fitting portion 18 surrounds the optical axis L and includes a fitting portion tapered surface 18a that is inclined 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 facing the image side X2 toward the inner periphery.

[0018] As shown in FIG. 2 , an elastic member is disposed between lens L2 and 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 lens L2 and the flange portion 17 of lens L3. In this example, a light-blocking sheet 9 made of resin is disposed between lens L2 and lens L3 in the optical axis direction X. The light-blocking sheet 9 is annular. The second O-ring 8 is located between the light-blocking sheet 9 and lens L3.

[0019] Lens L4 is made of resin. As shown in Figures 2, 4, and 5, 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 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 the center that protrudes toward the image side X2.

[0020] As shown in Fig. 4, a fitted portion 22 into which the fitting portion 18 of the lens L3 fits is provided on the object-side end surface X1 of the flange portion 21. The fitted portion 22 includes a fitted-portion tapered surface 22a that surrounds the optical axis L and inclines inward toward the image side X2, and a fitted-portion end surface 22b that extends perpendicular to the optical axis L from the image-side X2 end of the fitted-portion tapered surface 22a toward the inner periphery. As shown in Fig. 2, 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 fitted-portion end surface 18b of the lens L3 and the fitted-portion end surface 22b of the lens L4 are spaced apart in the optical axis direction X. In this example, the image-side end face X2 of the outer peripheral portion of the fitting portion 18 of the flange portion 17 of the lens L3 and the object-side end face X1 of the outer peripheral portion of the fitted portion 22 of the flange portion 21 of the lens L4 come into contact in the optical axis direction X. As a result, the lens L3 is placed on the lens L4, and the lens L3 is positioned in the optical axis direction X.

[0021] Lens L5 is made of glass. As shown in FIG. 2 , 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. Lens L5 is a biconvex lens. As shown in FIGS. 2 and 7 , the image side X2 of the flange 25 is a contacted portion 26 with which lens L6 contacts from the object side X1. A cross section of the contacted portion 26 cut along the optical axis L is an arc that curves toward the object side X1 toward the outer periphery. As shown in FIG. 7 , the image side X2 surface of the contacted portion 26 is continuous without a step with the outer periphery of the lens surface 24a of the image side X2 of the lens body 24.

[0022] As shown in FIG. 2 , a resin holder 28 is disposed radially outside the lens L5. As shown in FIG. 8 , the holder 28 is annular. The holder 28 includes a central portion 29 adjacent to the lens L5 with a gap 28 a in the radial direction, and an outer peripheral portion 30 located on the outer periphery of the central portion 29 and thicker in the optical axis direction X than the central portion 29. The object-side X1 surface of the central portion 29 inclines from the outer peripheral portion 30 toward the image side X2 as it extends from the outer peripheral portion 30 toward the inner periphery. The central portion 29 and the outer peripheral portion 30 are provided with cutouts 31 cut out from the object side X1 and the inner periphery at three locations in the circumferential direction. The bottom surfaces of the cutouts 31 (surfaces facing the object side X1) are continuous with the inner periphery edge of the central portion 29.

[0023] Here, the diaphragm 33 is disposed between the lens L4 and the lens L5. The diaphragm 33 is an annular sheet, and is sandwiched between the lens L4 and the holder 28 and supported at a predetermined position in the optical axis direction X.

[0024] The lens L6 is made of resin. That is, both the object-side lens L61 and the image-side lens L62 are made of resin. As shown in Fig. 2, 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.

[0025] As shown in FIG. 6 , the flange portion 36 of the object-side lens L61 has an inclined surface 36s on the object side X1. The inclined surface 36s is a tapered surface extending toward the object side X1 toward the outer periphery. Although not shown in FIG. 6 , the inclined surface 36s is provided with a contact portion 37N1 that contacts the contacted portion 26 of the lens L5, which will be described in detail later (see FIG. 12A ). The contacted portion 26 and the contact portion 37N1 are in point contact. The flange portion 36 of the object-side lens L61 has an annular end face 38 (see FIG. 2 ) on the image side X2 that is perpendicular to the optical axis L.

[0026] 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 image side X2. 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, as shown in FIG. 7 , 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.

[0027] As shown in FIG. 2, lens L5 is stacked on lens L6. Lens L4 is stacked on lens L6 via holder 28. Lens L4, holder 28, lens L5, and lens L6 form a stacked body 44. Lens L3 is stacked on lens L4. That is, lens L3 is stacked in stacked body 44. A plate-shaped cover 10 is disposed on the image side X2 of lens L6. (Lens Barrel) As shown in FIGS. 2 and 3, lens unit 1 includes a lens barrel 2, which includes 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. Both first lens barrel 3 and second lens barrel 4 are resin injection molded products formed by injecting resin into a mold. Lens L1 is housed in first lens barrel 3. Lenses L2 to L6 and holder 28 are housed in the second lens barrel 4. The second lens barrel 4 is held on the inner periphery of the first lens barrel 3. (First Lens Barrel and Lens L1) FIG. 9 is a cross-sectional view of the first lens barrel 3. The first lens barrel 3 is cylindrical and 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 FIGS. 3 and 9 , the first lens barrel 3 has an object-side step 101 at the object-side X1 end of its inner periphery and an image-side step 102 at the image-side X2 end. The first lens barrel 3 also has an intermediate step 103 between the object-side step 101 and the image-side step 102 in the optical axis direction X of its inner periphery.

[0028] 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 facing radially inward, 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 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.

[0029] The housing portion 108 includes a peripheral wall surface 107, a support surface 105, and a crimped portion 109. As shown in FIG. 2 , the peripheral wall surface 107 faces the lens L1 from the radially outer side. The support surface 105 faces the end face 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.

[0030] 3, 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 positioning portions that position the second lens barrel 4 in the radial direction.

[0031] 3 and 10 , the image-side step portion 102 includes an annular image-side end surface 112 facing the object side X1, and an annular image-side inner wall surface 113 extending from the inner peripheral edge of the image-side end surface 112 toward the image side X2 and reaching the image side X2 end of the first lens barrel 3. The image-side end surface 112 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 locations in the circumferential direction, equiangularly spaced apart. The ribs 114 are image-side positioning portions for positioning the second lens barrel 4 in the optical axis direction X.

[0032] The intermediate step portion 103 includes an annular step end surface 116 facing the object side X1 and an annular step wall surface 117 extending from the inner peripheral end of the step end surface 116 toward the image side X2. In this example, the intermediate step portion 103 is provided with notched grooves 118 at multiple locations in the circumferential direction, extending in the optical axis direction X and dividing the step end surface 116 and the step wall surface 117 in the circumferential direction. In this example, the notched grooves 118 are provided at three locations in the circumferential direction, equiangularly spaced. Therefore, the intermediate step portion 103 is divided into three parts in the circumferential direction by the notched grooves 118. The bottom surface (the surface facing the inner peripheral side) of the notched groove 118 is a tapered surface, and the inner diameter dimension decreases toward the image side X2. As shown in FIG. 2, the bottom surface of the notched groove 118 is continuous with an inner peripheral surface portion of the first lens barrel 3 that extends from the outer peripheral end of the image-side end face 112 of the image-side step portion 102 toward the object side X1.

[0033] As shown in FIG. 3 , the notched groove 118 is located at the same angular position as the rib 114 of the image-side step 102. The notched groove 118 is also located at the same angular position as the object-side protrusion 110 of the object-side step 101. When connecting the first lens barrel 3 and the second lens barrel 4, which is located on the inner periphery of the first lens barrel 3, adhesive is applied to the step end faces 116 of each of the three divided intermediate step portions 103. This provides a lens barrel connection adhesive layer 51 on the step end faces 116 and step wall surfaces 117. (Second Lens Barrel and Lenses L2 to L6) FIG. 10 is a perspective view of the second lens barrel 4 as seen from the object side. FIG. 11 is a cross-sectional view of the second lens barrel 4. The area surrounded by a chain line in FIG. 11 is a partially enlarged view of the area around the fitting protrusion 210. The second lens barrel 4 houses the lens L2, lens L3, lens L4, lens L5, holder 28, and lens L6 on its inner periphery.

[0034] 10 and 11 , the second lens barrel 4 has an object-side step 201 at the end portion of its inner circumferential surface on the object side X1. The second lens barrel 4 also has an image-side step 202 at the end portion on the image side X2. The second lens barrel 4 also has a positioning step 203 between the object-side step 201 and the image-side step 202, closer to the image-side step 202 than the object-side step 201. The second lens barrel 4 also has a cover holder 204 at the end portion on the image side X2 that holds the cover 10.

[0035] 11 , 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 end of the seating surface 205 toward the image side X2, and a peripheral wall surface 207 extending from the outer peripheral end of the seating surface 205 toward the object side X1. The annular wall surface 206 is a tapered surface whose inner diameter increases toward the object side X1. In the second lens barrel 4, the object side X1 of the object-side step 201 is a housing portion 208 that houses the outer peripheral edge portion of the lens L2.

[0036] The accommodation portion 208 includes a peripheral wall surface 207, a seating surface 205, and a crimped portion 209. As shown in Fig. 2, the peripheral wall surface 207 faces the lens L2 from the radially outer side. 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 109 abuts against the lens L2 from the object side X1 at a position overlapping with the seating surface 205 when viewed from the optical axis direction X.

[0037] As shown in FIG. 10 , the peripheral wall surface 207 is a tapered surface that slopes from the seating surface 205 outward toward the object side X1. The peripheral wall surface 207 has engagement protrusions 210A at multiple circumferentially spaced locations that are pressure-bonded 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 have, at their inner peripheral ends, pressure-bonding surfaces 210a that are parallel to the optical axis L. The engagement protrusions 210A also have curved surfaces 210b that curve from the pressure-bonding surfaces 210a outward toward the object side X1. The pressure-bonding surfaces 210a of the multiple engagement protrusions 210A are pressure-bonded to the lens L2 accommodated in the accommodation portion 208 from the radially outer side, thereby positioning the lens L2 in the radial direction.

[0038] As shown in Fig. 11 , the image-side step portion 202 includes an annular image-side end surface 212 facing the object side X1, and an image-side inner wall surface 213 extending from the inner peripheral end of the image-side end surface 212 to the image side X2. The image-side inner wall surface 213 is a tapered surface that slopes outward toward the image side X2. As shown in Fig. 2 , the image-side end surface 212 faces the image-side lens L62 of the lens L6 with a gap in between in the optical axis direction X. The cover holder 204 is provided on the outer peripheral side of the image-side inner wall surface 213.

[0039] 10 and 11 , the positioning step 203 includes an annular positioning surface 215 facing the object side X1, and a positioning step peripheral wall surface 216 extending from the inner peripheral end of the positioning surface 215 toward the image side X2. The 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. In this example, the positioning ribs 217 are provided at three positions in the circumferential direction, equiangularly spaced apart. The lower end of the positioning step peripheral wall surface 216 reaches the image-side end surface 212 of the image-side end surface 212. The positioning step peripheral wall surface 216 faces the image-side lens L62 of the lens L6 with a gap therebetween in the radial direction.

[0040] 2, the positioning rib 217 is a positioning portion that abuts against the flange portion 36 of the object-side lens L61 of the lens L6 from the image side X2, thereby positioning the lens L6 in the optical axis direction X. Here, the flange portion 36 of the object-side lens L61 of the lens L6 abuts against the positioning portion, so that the stacked body 44 consisting of the lens L4, holder 28, lens L5, and lens L6, and the lens L3 are positioned in the optical axis direction X.

[0041] More specifically, the holder 28 is supported from the image side X2 by the lens L6, thereby being positioned at a predetermined position in the optical axis direction X. The lens L4 is supported from the image side X2 by the holder 28, thereby being positioned at a predetermined position in the optical axis direction X. The lens L5 is positioned in the optical axis direction X and the radial direction by coming into contact with the lens L6. The lens L3 is positioned in the optical axis direction X and the radial direction by fitting into the lens L4. Here, when the lens L5 is positioned in the optical axis direction X and the radial direction, the lens L5 and the holder 28 do not come into contact. When the lenses L3 and L4 are positioned in the optical axis direction X and the radial direction, the lens L3 does not come into contact with the second lens barrel 4. The lens L3, lens L4, holder 28, and lens L5 are located between the object-side step 201 and the positioning step 203 in the optical axis direction X.

[0042] As shown in Figures 10 and 11, on the inner circumferential surface of the second lens barrel 4, an inner circumferential surface portion 4a located radially outside the object-side lens L61 of the lens L6 is a tapered surface that slopes outward toward the object side X1. The inner circumferential surface portion 4a has engagement protrusions 210B at multiple circumferentially spaced locations that are pressed against the lens L6. The engagement protrusions 210B are provided at six circumferential locations, equiangularly spaced apart. The engagement protrusions 210B have, at their inner circumferential ends, compression surfaces 210a that are parallel to the optical axis L. The engagement protrusions 210B also have curved surfaces 210b that curve outward from the compression surface 210a toward the object side X1. The compression surfaces 210a of the multiple engagement protrusions 210B are pressed against the lens L6 housed in the second lens barrel 4 from the radially outer side, thereby positioning the lens L6 in the radial direction.

[0043] Furthermore, on the inner peripheral surface of the second lens barrel 4, an inner peripheral surface portion 4b located radially outward of the holder 28 is a tapered surface that slopes outward toward the object side X1. The inner peripheral surface portion 4b has engagement protrusions 210C that are pressure-bonded to the lens L6 at multiple circumferentially spaced locations. The engagement protrusions 210C are provided at six circumferential locations, equiangularly spaced apart. The engagement protrusions 210C have, at their inner peripheral ends, pressure-bonding surfaces 210a that are parallel to the optical axis L. The engagement protrusions 210C also have curved surfaces 210b that curve outward from the pressure-bonding surfaces 210a toward the object side X1. The pressure-bonding surfaces 210a of the multiple engagement protrusions 210C are pressure-bonded from the radially outer side to the holder 28 housed in the second lens barrel 4, thereby positioning the holder 28 in the radial direction.

[0044] Furthermore, on the inner peripheral surface of the second lens barrel 4, an inner peripheral surface portion 4c located radially outside the lens L4 is a tapered surface that slopes outward toward the object side X1. The inner peripheral surface portion 4c has engagement protrusions 210D at multiple circumferentially spaced locations that press against the lens L4. The engagement protrusions 210D are provided at six circumferential locations, equiangularly spaced apart. The engagement protrusions 210D have, at their inner peripheral ends, compression surfaces 210a that are parallel to the optical axis L. The engagement protrusions 210D also have curved surfaces 210b that curve from the compression surface 210a outward toward the object side X1. The compression surfaces 210a of the multiple engagement protrusions 210D press against the lens L4 housed in the second lens barrel 4 from the radially outer side, thereby positioning the lens L4 in the radial direction.

[0045] Furthermore, on the inner peripheral surface of the second lens barrel 4, an inner peripheral surface portion 4d located radially outside the lens L3 is a tapered surface that slopes outward toward the object side X1. The inner peripheral surface portion 4d located radially outside the lens L3 is continuous without a step with the image side X2 of the annular wall surface 206 of the object-side step portion 201. The inner peripheral surface portion 4d is provided with guide protrusions 220 at multiple locations spaced apart in the circumferential direction that guide the lens L3 in the optical axis direction X. The guide protrusions 220 are provided at six locations in the circumferential direction, equiangularly spaced apart. The guide protrusions 220 are provided with a guide surface 220a at their inner peripheral end that is parallel to the optical axis L. The guide protrusions 220 are also provided with a curved surface 220b that curves outward from the crimping surface 210a toward the object side X1. When the lens L3 is fitted to the lens L4, the guide protrusions 220 are located radially outward of the lens L3, but do not come into contact with the lens L3. The guide surfaces 220a of the guide protrusions 220 face the lens L3 with a small radial gap therebetween.

[0046] Here, the second O-ring 8 is disposed on the object side X1 of the multiple guide protrusions 220, radially inward of the annular wall surface 206 of the object-side step portion 201. As shown in FIG. 2 , the second O-ring 8 is compressed in the optical axis direction X between the lens L2 and the lens L3 housed in the housing portion 208.

[0047] 11 , a first inclination angle θ1 at which the tapered inner circumferential surface portion 4a located radially outward of lens L6 is inclined with respect to the optical axis L is different from a second inclination angle θ2 at which the tapered inner circumferential surface portion 4c located radially outward of lens L4 is inclined with respect to the optical axis L. That is, the inclination of the inner circumferential surface portions 4a to 4d located radially outward of each lens and holder 28 can be set appropriately in accordance with the outer diameter of each lens or holder 28. Note that, on the inner circumferential surface of the second lens barrel 4, the inner circumferential surface portion 4a located between the object-side step 201 and the positioning step 203 is inclined overall outward toward the object side X1.

[0048] Next, the second lens barrel 4 has an annular outer surface positioning surface 223 at the object side X1 end portion of its outer surface. The outer surface positioning surface 223 is located radially outward of the housing portion 208. The outer surface positioning surface 223 faces radially outward. The second lens barrel 4 also has an outer surface image side step 224 at the image side X2 portion of its outer surface. The outer surface image side step 224 has an annular surface 225 facing the image side X2 and an outer surface portion 226 extending from the outer peripheral end of the annular surface 225 toward the object side X1. Furthermore, the second lens barrel 4 has an outer surface intermediate step 227 between the object side X1 end portion of its outer surface (outer surface positioning surface 223) and the outer surface image side step 224. The outer peripheral surface intermediate step portion 227 has an annular surface 228 facing the image side X2 and an outer peripheral surface portion 229 extending from the inner peripheral end of the annular surface 228 toward the image side X2.

[0049] (Lens L5 and Object-Side Lens L61) Next, the lens L5 and the object-side lens L61 will be described in detail. FIG. 12A is a cross-sectional view of the lens L5 and the object-side lens L61. As shown in FIG. 12A , the lens unit 1 includes a lens L5 arranged on the object side X1 and an object-side lens L61 arranged on the image side X2. The lens L5 and the object-side lens L61 are arranged in the direction of the optical axis. The lens L5 is an example of a "first lens" in the technology of the present disclosure. The object-side lens L61 is an example of a "second lens" in the technology of the present disclosure. The object side X1 is an example of a "subject side" in the technology of the present disclosure. The image side X2 is an example of an "imaging surface side" in the technology of the present disclosure.

[0050] The lens L5 and the object-side lens L61 come into contact with each other via the contacted portion 26 of the lens L5 and the contact portion 37N1 of the object-side lens L61.

[0051] A cross section of the contacted portion 26 cut along the optical axis L is an arc that curves toward the outer periphery and the image side X2.

[0052] The surface of the flange portion 36 of the object-side lens L61 facing the lens L5 is an inclined surface 36s (see also FIG. 6 ) that is inclined with respect to the optical axis L, and a contact portion 37N1 is provided on a part of the inclined surface 36s. The cross section of the contact portion 37N1 in a plane including the optical axis L and the contact portion 37N1 has a convex shape toward the lens L5, specifically, a predetermined region of the inclined surface 36s has a shape that rises toward the lens L5.

[0053] As shown in FIG. 15A , the convex cross-section of the contact portion 37N1 is curved, and the curvature of the curved line in the curved shape is constant. Specifically, the curved shape is an arc. For example, the center 37c of the arc is located on the inclined surface 36s. That is, the shape of the contact portion 37N1 is a hemisphere that rises from the inclined surface 36s toward the lens L5. Therefore, the line connecting the highest point 37m of the arc and the center 37c of the arc intersects with the inclined surface 36s, specifically, for example, is perpendicular to the inclined surface 36s. That is, the direction in which the arc rises is perpendicular to the inclined surface 36s.

[0054] The direction in which the arc rises is not limited to being perpendicular to the inclined surface 36s. For example, as shown in Fig. 12B, the direction in which the arc rises may be parallel to the optical axis L. By making the direction in which the arc rises parallel to the optical axis L in this way, it becomes easier to remove the lens 6L from the mold used to mold the resin lens L6.

[0055] 13A is a diagram showing how the lens L5 and the object-side lens L61 come into contact with each other at three locations outside the optically effective area of ​​the lenses. FIG. 13A is a diagram showing the lens L5 as viewed from the object side X1.

[0056] 13A, the lens L5 and the object-side lens L61 come into contact with each other at three locations. There are three pairs of contact portions 37N1 and contacted portions 26. The three pairs of contact portions 37N1 are located at equal intervals on a concentric circle 26C centered on the optical axis L.

[0057] As described above, the lens L5 includes a lens body 24 having a lens surface and a flange 25 surrounding the lens body 24. The lens body 24 and the flange 25 are separated by a boundary line 245K (i.e., a concentric circle centered on the optical axis L). The lens surface closer to the optical axis L than the boundary line 245K is the optically effective area, and the area outside the boundary line 245K is the area outside the optically effective area (the surface of the flange 25). The contact portion 37N1 contacts the area outside the optically effective area of ​​the lens L5 outside the boundary line 245K. The contacted portion 26 of the lens L5 also contacts the area outside the optically effective area of ​​the object-side lens L61 (the surface of the flange 36). When the contact portion 37N1 is viewed from the object-side X1 side, the shape of the contact portion 37N1 is a circle. The contact portion 37N1 contacts the contacted portion 26 at a point (i.e., position 37m (see also FIG. 15A)).

[0058] The shape of the contact portion 37N1 as viewed from the object side X1 is not limited to a circle. As shown in Fig. 13B, the shape of the contact portion 37N11 as viewed from the object side X1 may be, for example, an ellipse.

[0059] Furthermore, as shown in FIG. 13C, the shape of the contact portion 37N12 as viewed from the object side X1 may be, for example, a shape that extends further than the contact portion 37N11 along the concentric circle 26C.

[0060] The shape of the contact portion 37N12 may be a shape that extends along the concentric circle 26C and a part of the concentric circle 26C is cut off, that is, the shape of the contact portion 37N12 may be a ring shape centered on the optical axis L with a part of the ring cut out.

[0061] 13A, the lens L5 and the object-side lens L61 are in contact with each other at three locations, i.e., there are three pairs of contact portions 37N1 and contacted portions 26. The number of pairs is not limited to three. There may be three or more pairs, or there may be two or one pair.

[0062] 14, a portion 24H of the effective area of ​​the lens L5 on the object-side lens L61 side is located closer to the image side X2 than a contact portion 37N1 of the object-side lens L61 that comes into contact with the lens L5. As shown in FIG. 12A (and FIG. 12B), the flange portion 36 of the object-side lens L61 has a surface 36H that is perpendicular to the optical axis L.

[0063] (Assembly of Lens Unit) When assembling the lens unit 1, first, a second unit assembling operation is performed in which lenses L2 to L6 are housed in the second lens barrel 4. Next, a lens barrel fixing operation is performed in which the second lens barrel 4 is held and fixed to the first lens barrel 3. After that, a first unit assembling operation is performed in which lens L1 is housed in the first lens barrel 3.

[0064] In the second unit assembly operation, first, lens L6 is manufactured by cementing object-side lens L61 and image-side lens L62 outside the second lens barrel 4. Lens L5 is stacked on object-side lens L61 of lens L6, and lens L5 and object-side lens L61 are brought into point contact with each other at each of three pairs of contact portion 37N1 and contacted portion 26. Thereafter, lens L6 is vibrated until the optical axis of lens L5 coincides with optical axis L, thereby aligning lens L5 and lens L6. As a result, lens L5 and lens L6 are positioned relative to each other in the optical axis direction X and the radial direction.

[0065] Alternatively, after bringing the lens L5 and the object-side lens L61 into point contact in each of the three pairs, adhesive may be applied to the outer periphery of the lens L6 between the object-side lens L61 and the lens L5, the lens L6 may be vibrated until the optical axis of the lens L5 coincides with the optical axis L, and the adhesive may then be hardened.

[0066] In the above example, the lens L6 is vibrated to perform alignment, but the lens L6 can also be stacked on the lens L5, and the lens L5 can be vibrated to perform alignment.

[0067] After the alignment is complete, adhesive is applied between lenses L1 and L2 on the outer periphery of contact line M. This adhesive is then cured. As a result, lenses L6 and L5 are fixed together by adhesive layer 52 formed therebetween (step ST3).

[0068] Next, the lenses L5 and L6, which are fixed to each other, are housed in the second lens barrel 4 from the object side X1. At this time, as can be seen from FIG. 10 , the lens L6 is press-fitted into the inner peripheral side of a plurality of fitting protrusions 210B provided on the inner peripheral surface of the second lens barrel 4 closest to the image side X2. As a result, the pressure-bonding surfaces 210a of the fitting protrusions 210B are pressed against the lens L6 (object-side lens L61) from the radially outer side, and the lens L6 is positioned in the radial direction. In addition, the flange portion 36 of the object-side lens L61 of the lens L6 is abutted against the positioning rib 217 of the positioning step portion 203 of the second lens barrel 4. As a result, the lens L6 is positioned in the optical axis direction X. Once the lens L6 is positioned in the optical axis direction X and the radial direction, the lens L5 fixed to the lens L6 is also positioned in the optical axis direction X and the radial direction.

[0069] The holder 28 is then inserted into the second lens barrel 4 from the object side X1. At this time, the holder 28 is press-fitted into the inner periphery of the second plurality of engaging protrusions 210C from the image side X2 on the inner periphery of the second lens barrel 4. This causes the pressure-bonding surfaces 210a of the engaging protrusions 210C to press against the holder 28 from the radially outer side, positioning the holder 28 in the radial direction. Furthermore, by abutting the holder 28 against the lens L6 from the object side X1, the holder 28 is supported by the lens L6 from the image side X2 and positioned in the optical axis direction X. Here, gaps 28a are formed between the inner periphery of the holder 28 and the lens L5. Therefore, adhesive is dispensed into these gaps 28a, and the holder 28 and the lens L5 are fixed together via an adhesive layer 53 (see FIG. 8 ). In this example, the adhesive is applied to the notches 31 provided in the outer periphery 30 of the holder 28. As a result, the adhesive flows along the central portion 29 and reaches the gap 28a between the holder 28, the inner peripheral surface, and the lens L5.

[0070] Thereafter, lens L4 is housed in the second lens barrel 4 from the object side X1. At this time, lens L4 is press-fitted into the inner periphery of the third fitting protrusions 210D from the image side X2 on the inner periphery of the second lens barrel 4. As a result, the pressure-bonding surfaces 210a of the fitting protrusions 210D are pressed against the lens L4 from the radially outer side, and lens L4 is positioned in the radial direction. Furthermore, by abutting lens L4 against holder 28 from the object side X1, lens L4 is supported by holder 28 from the image side X2 and is positioned in the optical axis direction X. Here, a laminated body 44 consisting of lens L4, holder 28, lens L5, and lens L6 is formed inside the second lens barrel 4.

[0071] Next, lens L3 is housed in the second lens barrel 4 from the object side X1. At this time, lens L3 is inserted onto the inner periphery of the multiple guide protrusions 220. As a result, lens L3 is guided in the optical axis direction X in a predetermined orientation, and the fitting portion 18 of lens L3 is inserted into the fitted portion 22 of lens L4. Furthermore, lens L3, guided by the guide protrusions 220, is pushed into lens L4 from the object side X1. As a result, the fitting portion 18 of lens L3 and the fitted portion 22 of lens L4 are fitted together. When the fitting portion 18 of lens L3 and the fitted portion 22 of lens L4 are fitted together, the fitting portion tapered surface 18a of the fitting portion 18 and the fitted portion tapered surface 22a of the fitted portion 22 are in surface contact. As a result, lens L3 is positioned radially relative to lens L4. Furthermore, when the fitting portion 18 of the lens L3 and the fitted portion 22 of the lens L4 are fitted together, the outer peripheral portion of the fitting portion 18 on the flange portion 17 of the lens L3 and the outer peripheral portion of the fitted portion 22 on the flange portion 21 of the lens L4 come into contact in the optical axis direction X. This positions the lens L3 in the optical axis direction X.

[0072] Thereafter, the second O-ring 8 is placed on the flange portion 17 of the lens L3 from the object side X1. Next, the light-shielding sheet 9 is supported on the support surface 105. Furthermore, the lens L2 is supported on the support surface 105 via the light-shielding sheet 9. At this time, the lens L2 is press-fitted into the inner peripheral side of the fitting protrusion 210A that is located closest to the object side X1 on the inner peripheral surface of the second lens barrel 4. As a result, the pressure-bonding surfaces 210a of the fitting protrusions 210A are pressed against the lens L2 from the radially outer side, and the lens L2 is positioned in the radial direction. Furthermore, the lens L2 is positioned in the optical axis direction X by abutting the lens L2 against the light-shielding sheet 9 from the object side X1.

[0073] Thereafter, a crimped portion 109 that bends inward is formed at the end portion of the second lens barrel 4 on the object side X1, and the crimped portion 109 is brought into contact with the outer peripheral edge portion of lens L2 from the object side X1. In this example, the crimped portion 109 is formed by thermal crimping. This completes the second unit assembly operation. When the second unit assembly operation is complete, the second O-ring 8 is compressed in the optical axis direction X between lens L2 and lens L3.

[0074] Next, a barrel fixing operation is performed to hold the second unit 60 to the first unit 50. In this operation, as can be seen from FIGS. 3 and 9 , adhesive is applied to the step end surfaces 116 of the three intermediate step portions 103 on the inner circumferential surface of the first barrel 3. After that, the second unit 60 is inserted into the inner circumferential side of the first barrel 3 from the object side X1. Then, as can be seen from FIGS. 11 and 9 , the annular surface 225 of the outer peripheral image-side step portion 224 on the image-side portion of the outer peripheral surface of the second barrel 4 is brought into contact with the rib 114 (image-side positioning portion) of the image-side step portion 102 on the inner circumferential surface of the first barrel 3. Furthermore, the annular outer peripheral positioning surface 223 on the end portion of the second barrel 4 on the object side X1 is brought into contact with the object-side protrusion 110 on the annular wall surface 106 of the object-side step portion 101 of the first barrel 3.

[0075] Here, the inner peripheral surface of the first lens barrel 3 and the outer peripheral surface of the second lens barrel 4 face each other with a gap between them, except for the contact portion between the image-side step 102 of the second lens barrel 4 and the image-side step 102 of the first lens barrel 3, and the contact portion between the annular positioning surface 215 of the second lens barrel 4 and the object-side step 101 of the first lens barrel 3. Therefore, the second lens barrel 4 is positioned relative to the first lens barrel 3 in the optical axis direction X and the radial direction by the two contact portions.

[0076] Furthermore, when the second unit 60 is inserted into the inner periphery of the first lens barrel 3, the intermediate step portion 103 on the inner periphery of the first lens barrel 3 and the outer periphery intermediate step portion 227 on the outer periphery of the second lens barrel 4 face each other with a gap therebetween. That is, the step end face 116 of the intermediate step portion 103 of the first lens barrel 3 and the annular surface 228 of the outer periphery intermediate step portion 227 of the second lens barrel 4 face each other with a gap in the optical axis direction X. Furthermore, the step wall surface 117 of the intermediate step portion 103 of the first lens barrel 3 and the outer periphery surface portion 229 of the outer periphery intermediate step portion 227 of the second lens barrel 4 face each other with a gap in the radial direction. Here, the adhesive applied to the step end face 116 of the intermediate step portion 103 of the first lens barrel 3 spreads to the step wall surface 117 when the second unit 60 is inserted into the inner periphery of the first lens barrel 3. 2 , a lens-barrel connecting adhesive layer 51 is interposed between the step end surface 116 of the intermediate step portion 103 of the first lens-barrel 3 and the annular surface 228 of the outer peripheral surface intermediate step portion 227 of the second lens-barrel 4. In addition, a lens-barrel connecting adhesive layer 51 is interposed between the step wall surface 117 of the intermediate step portion 103 of the first lens-barrel 3 and the outer peripheral surface portion 229 of the outer peripheral surface intermediate step portion 227 of the second lens-barrel 4. The intermediate step portion 103 of the first lens-barrel 3 and the outer peripheral surface intermediate step portion 227 of the second lens-barrel 4 are an adhesive fixing portion that connects the first lens-barrel 3 and the second lens-barrel 4 via the lens-barrel connecting adhesive layer 51.

[0077] Next, in the first unit assembly operation, the first O-ring 7 is placed on the support surface 105 of the first lens barrel 3. Then, the lens L1 is supported on the support surface 105 via the first O-ring 7. After that, a crimped portion 109 that bends inward is formed at the end portion on the object side X1 of the first lens barrel 3. This causes the crimped portion 109 to abut against the outer periphery of the lens L1 from the object side X1. In this example, the crimped portion 109 is formed by thermal crimping. Once the crimped portion 109 is formed, the first O-ring 7 is compressed in the optical axis direction X between the end face on the image side X2 of the lens L1 and the support surface 105 of the first lens barrel 3.

[0078] Here, when lens L1 is held in the first lens barrel 3, the end face 11 on the image side X2 of lens L1 is in surface contact with the annular protrusion 15 provided on the flange portion 14 of lens L2 held in the second lens barrel 4.

[0079] 2 , an air passage 70 is formed between the first lens barrel 3 and the second lens barrel 4, extending from the space between the image-side X2 end 3 a of the first lens barrel 3 and the image-side X2 end 4 e of the second lens barrel 4, through a space between adjacent ribs 114 in the circumferential direction on the image-side step 102 of the first lens barrel 3, a notched groove 118 provided in the intermediate step 103 of the first lens barrel 3, and a space between adjacent object-side protrusions 110 in the circumferential direction on the annular wall surface 106 of the object-side step 101 of the first lens barrel 3. The air passage 70 communicates with the space between the lens L1 and the support surface 105, and on the inner circumferential side of the first O-ring 7.

[0080] (Effect) In this embodiment, in each of the three pairs of the contact portion 37N1 and the contacted portion 26, the lens L5 and the lens L61 are brought into point contact with each other, and then the lens L6 is vibrated until the optical axis of the lens L5 coincides with the optical axis L, thereby aligning the lens L5 and the lens L6. Thus, in this embodiment, the alignment of two adjacent lenses L5 and L6 can be performed simply by bringing the two lenses into contact.

[0081] Incidentally, when a lens unit is applied to an on-board camera, the on-board camera may be placed outside the vehicle, and the lens unit may be used in a high-temperature environment. In this case, a configuration using only a resin lens may result in degradation of captured images due to thermal expansion. To prevent image degradation, a glass lens may be used. However, since it is difficult to provide a flange portion for a glass lens as with a resin lens, conventional techniques provide a positioning holder on the radially outer side of the glass lens. When a glass lens is held by a holder, the glass lens must be positioned (aligned) with high precision. During alignment, the glass lens may be positioned by sliding it relative to other lenses. When positioning the glass lens by sliding it, if the contact area between the glass lens and other lenses is large, frictional resistance increases and alignment precision decreases.

[0082] In this embodiment, the cross section of the contact portion 37N1 in a plane including the optical axis L and the contact portion 37N1 has a convex shape toward the lens L5. Therefore, the contact area of ​​the portion where the object-side lens L61 contacts the lens L5 is smaller than that of the prior art. Therefore, if the contact area can be reduced in this way, the static friction coefficient during centering can be made smaller than that of the prior art. Therefore, in this embodiment, centering can be easily performed while the lenses L5 and L6 are in contact with each other.

[0083] In this embodiment, a portion 24H of the effective area of ​​the lens L5 on the object-side lens L61 side is located closer to the image side X2 than a contact portion 37N1 of the object-side lens L61 that contacts the lens L5. Therefore, in this embodiment, the lens L5 can be dropped into contact with the object-side lens L61, making assembly easier.

[0084] In this embodiment, the flange portion 36 of the object-side lens L61 has a surface 36H that is perpendicular to the optical axis L. Therefore, this embodiment can easily perform a black coating process that prevents stray light from reaching the object-side lens L61.

[0085] In the above-described embodiment, the cross section of the contacted portion 26 of the lens L5 cut along the optical axis L is an arc that curves toward the outer periphery and the image side X2, and the cross section of the contact portion 37N1 of the object-side lens L61 in a plane including the optical axis L and the contact portion 37N1 is also arc-shaped (see FIG. 15A ). The technology of the present disclosure is not limited to this.

[0086] (First to fourth modified examples) Figures 15B to 15E show first to fourth modified examples in which the shape of the contacted portion 26 of lens L5 is the same as the shape of the contacted portion 26 in the above embodiment, but the contact portion of object-side lens L61 has a different shape from the contact portion 37N1 in the above embodiment.

[0087] In the first modified example shown in Figure 15B, the cross section of the contact portion 37N2 where the object-side lens L61 contacts the lens L5, in a plane including the optical axis L and the contact portion 37N2, has an elliptical arc shape that rises toward the lens L5.

[0088] 15C , the cross section of the contact portion 37N3 where the object-side lens L61 contacts the lens L5, taken along a plane including the optical axis L and the contact portion 37N3, has a curved shape that rises toward the lens L5, and the curvature of the curved line of the curved shape changes. Note that the curvature of the curved line becomes smaller (or larger) as the point on the curved line becomes closer to the object side X1.

[0089] In the third modified example shown in Figure 15D, the cross section of the contact portion 37N4 at which the object-side lens L61 contacts the lens L5, in a plane including the optical axis L and the contact portion 37N4, has an angular shape that protrudes toward the lens L5, and the intersection angle of the two sides that form the corner of the angular shape is an acute angle.

[0090] 15E , a cross section of a contact portion 37N5 at which the object-side lens L61 contacts the lens L5, taken along a plane including the optical axis L and the contact portion 37N5, has an angular shape that protrudes toward the lens L5, and the intersection angle of two sides that form the corner of the angular shape is an obtuse angle. The third and fourth modifications can reduce the contact area more than the above embodiment, the first modification, and the second modification.

[0091] 16A to 16E show the fifth to ninth modified examples, respectively. In the fifth to ninth modified examples, contact portions 26N1 to 26N5 that come into contact with the object-side lens L61 are provided on the surface of the object-side lens L61 of the flange portion 25 of the lens L5. In the fifth to ninth modified examples, the surface of the flange portion 36 of the object-side lens L61 on the lens L5 side is an inclined surface 36s that is inclined with respect to the optical axis L, and the inclined surface 36s does not have a portion that is convex toward the lens L5 of the above-described embodiment. The contact portions 26N1 to 26N5 come into contact with the contacted portion 37 of the inclined surface 36s.

[0092] In the fifth modified example shown in Figure 16A, the cross section of the contact portion 26N1 where the lens L5 comes into contact with the object-side lens L61 in a plane including the optical axis L and the contact portion 26N1 has an angular shape that protrudes toward the object-side lens L61, and the intersection angle of the two sides that form the corner of the angular shape is an obtuse angle.

[0093] 16B , a cross section of a contact portion 26N2 at which the lens L5 contacts the object-side lens L61, taken along a plane including the optical axis L and the contact portion 26N2, has an angular shape that protrudes toward the object-side lens L61, and the intersection angle of two sides that form the angle in the angular shape is an acute angle. The fifth and sixth modifications can reduce the contact area more than the seventh to ninth modifications described below.

[0094] 16C , the cross section of a contact portion 26N3 where the lens L5 contacts the object-side lens L61, taken along a plane including the optical axis L and the contact portion 26N3, has a curved shape that rises toward the object-side lens L61, and the curvature of the curved line of the curved shape changes. Note that the curvature of the curved line increases (or decreases) as the point on the curved line approaches the object side X1.

[0095] In the eighth modified example shown in Figure 16D, the cross section of the contact portion 26N4 where the lens L5 comes into contact with the object-side lens L61 in a plane including the optical axis L and the contact portion 26N4 has a curved shape that rises toward the object-side lens L61, and the curved shape is an elliptical arc shape.

[0096] In the ninth modified example shown in Figure 16E, the cross section of the contact portion 26N5 where the lens L5 comes into contact with the object-side lens L61 in a plane including the optical axis L and the contact portion 26N5 has a curved shape that rises toward the object-side lens L61, and the curved shape is an arc shape.

[0097] 17A to 17E show the tenth to fourteenth modified examples, respectively. A cross section of contact portions 26N1 to 26N5 where the lens L5 contacts the object-side lens L61, taken on a plane including the optical axis L and contact portions 26N1 to 26N5, is defined as a first cross section, and a cross section of contact portions 37N1 to 37N5 where the object-side lens L61 contacts the lens L5, taken on a plane including the optical axis L and contact portions 37N1 to 37N5, is defined as a second cross section.

[0098] In the tenth modified example shown in Figure 17A, the first cross section has an angular shape that protrudes toward the object-side lens L61, and the intersection angle of the two sides that form the corner of the angular shape is an obtuse angle, and the second cross section has a curved shape that rises toward the lens L5, and the curved shape is an arc shape.

[0099] In the eleventh modified example shown in Figure 17B, the first cross section has an angular shape that protrudes toward the object-side lens L61, and the intersection angle of the two sides that form the corner in the angular shape is an acute angle, and the second cross section has a curved shape that rises toward the lens L5, and the curved shape is an elliptical arc shape.

[0100] In the twelfth modified example shown in Fig. 17C, the first cross section has a curved shape that rises toward the object-side lens L61, and the curvature of the curved line of the curved shape changes. The curvature of the curved line becomes smaller (or larger) as the point on the curved line becomes closer to the object side X1. The second cross section has a curved shape that rises toward the lens L5, and the curvature of the curved line of the curved shape changes. The curvature of the curved line becomes larger (or smaller) as the point on the curved line becomes closer to the object side X1.

[0101] In the thirteenth modified example shown in Figure 17D, the first cross section has a curved shape that rises toward the object-side lens L61, and the curved shape is an elliptical arc shape, and the second cross section has an angular shape that protrudes toward the lens L5, and the intersection angle of the two sides that form the corner in the angular shape is an acute angle.

[0102] 17E, the first cross section has a curved shape that rises toward the object-side lens L61, and the curved shape is an arc shape, and the second cross section has an angular shape that protrudes toward the lens L5, and the intersection angle of two sides that form the corner of the angular shape is an obtuse angle. The tenth to fourteenth variations can reduce the contact area of ​​the contact portion more than the above embodiment and the first to ninth variations. The tenth, eleventh, thirteenth, and fourteenth variations can reduce the contact area of ​​the contact more than the twelfth variation.

[0103] (Other Modifications) In addition to the above examples, the combinations of the contact portions of the lens L5 and the object-side lens L61 include the following combinations.

[0104] The contact portion of the lens L5 is the contact portion 26N1, and the contact portion of the object-side lens L61 is the contact portion 37N2 or the contact portion 37N3.

[0105] The contact portion of the lens L5 is the contact portion 26N2, and the contact portion of the object-side lens L61 is the contact portion 37N1 or the contact portion 37N3.

[0106] The contact portion of the lens L5 is the contact portion 26N3, and the contact portion of the object-side lens L61 is any one of the contact portions 37N1, 37N2, 37N4, and 37N5.

[0107] The contact portion of the lens L5 is the contact portion 26N4, and the contact portion of the object-side lens L61 is any one of the contact portions 37N1 to 37N3 and 37N5.

[0108] The contact portion of the lens L5 is the contact portion 26N5, and the contact portion of the object-side lens L61 is one of the contact portions 37N1 to 37N4.

[0109] In summary, the above-described embodiment and the tenth to fourteenth modifications include the following content of the technology of the present disclosure.

[0110] The first cross section has a curved shape that is convex toward the object-side lens L61 or a protruding shape that is directed toward the object-side lens L61, and the second cross section has a curved shape that is convex toward the lens L5.

[0111] Alternatively, the first cross section has a curved shape convex toward the object-side lens L61, and the second cross section has a curved shape convex toward the object-side lens L61, or a protruding shape toward the object-side lens L61.

[0112] (Imaging Device) Fig. 18 is a schematic diagram of an imaging device 350. As shown in Fig. 18, the imaging device 350 includes a lens unit 1, an imaging section 300, and a signal processing section that performs arithmetic processing on an output signal from the imaging section 300.

[0113] The imaging device 350 is an example of a "camera module" of the technology of the present disclosure.

[0114] The imaging unit 300 includes an infrared cut filter and an imaging element. The imaging element captures an image of a subject formed by the lens unit 1 and converts the image into an electrical signal, and may be, for example, a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor). The imaging element is positioned so that its imaging surface coincides with the image plane of the lens unit 1.

[0115] The image capturing device 350 can be used as an in-vehicle image capturing device, specifically, a drive recorder, for example. The image capturing device 350 captures images of the front, rear, or side of the vehicle.

[0116] A band-pass filter may be used instead of the infrared cut filter.

[0117] This embodiment can provide an imaging device with excellent optical characteristics.

[0118] (Further Other Modifications) In the embodiment and each modification described above, (lens L5, object-side lens L61) has been taken as an example of a set (an example of a "first lens" and an example of a "second lens"), but the technology of the present disclosure is not limited to this. For example, the set (an example of a "first lens" and an example of a "second lens") may be (lens L1, lens L2) and (lens L3, lens L4).

[0119] L5 Lens L61 Object-side lens 26 Contacted portion 37N1 Contact portion 350 Imaging device

Claims

1. A lens unit comprising a first lens arranged on the subject side and a second lens arranged on the imaging surface side, the first lens and the second lens arranged in the direction of the optical axis, the first lens and the second lens being in contact in at least three locations and outside the optically effective area of ​​the lenses, wherein a cross section of a portion where at least one of the first lens and the second lens contacts the other, taken on a plane including the optical axis and the portion, has a convex shape toward the other.

2. A lens unit as described in claim 1, wherein a portion of the effective area of ​​the first lens facing the second lens is located closer to the imaging surface than a portion of the second lens that contacts the first lens.

3. The lens unit according to claim 2, wherein a portion of said second lens outside said effective area has a surface perpendicular to the optical axis.

4. The lens unit according to claim 1 or 2, wherein the convex shape is a curved shape or a protruding shape.

5. The lens unit according to claim 4, wherein the curvature of the curved line in said curved shape is constant or varies.

6. The lens unit according to claim 4 or 5, wherein the curved shape is a circular arc shape or an elliptical arc shape.

7. The lens unit according to claim 4, wherein the protruding shape is an angular shape.

8. The lens unit according to claim 7, wherein an intersection angle between two sides forming a corner in the angular shape is an obtuse angle or an acute angle.

9. A lens unit as described in claim 1 or claim 2, wherein a first cross section is a cross section in a plane including the optical axis and a portion where one of the first lens and the second lens contacts the other, and a second cross section is a cross section in a plane including the optical axis and a portion where the other of the first lens and the second lens contacts the one, the first cross section has a curved shape that is convex toward the other, or a protruding shape toward the other, and the second cross section has a curved shape that is convex toward the one, or the first cross section has a curved shape that is convex toward the other, or a protruding shape toward the one.

10. A camera module comprising a lens unit according to claim 1 or 2.

Images