Lens unit

Abstract

To provide a lens unit which can suppress occurrence of optical axis deviation of a lens of a first lens barrel and a lens of a second lens barrel even when a gap is provided between the first lens barrel and the second lens barrel.SOLUTION: A lens unit 1 has a first lens barrel 3 which stores a lens L1 and is made of a resin, and a second lens barrel 4 which stores a lens L2, is held on the inner peripheral side of the first lens barrel 3 and is made of a resin. The first lens barrel 3 includes an object side projection 110 facing an end part of an object side X1 of the second lens barrel 4 so as to position the second lens barrel 4 in a radial direction, and an object side projection 110 facing an image side part of the second lens barrel 4 so as to position the second lens barrel 4 in the radial direction. A first clearance is provided between the object side projection 110 and the second lens barrel 4. A second clearance is provided between an image side outer peripheral surface part 227 and the second lens barrel 4. The first clearance is smaller than the second clearance.SELECTED DRAWING: Figure 3

Description

[Technical field]

[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 peripheral side of the first barrel.

[0002] A lens unit in which a lens barrel that holds a lens is composed of two members, a first barrel and a second barrel, is described in Patent Document 1. In this document, the first barrel is made of resin and holds a first lens at its end portion on the object side. The second barrel is made of resin and is located on the inner circumference side of the first barrel. A plurality of lenses are housed in the second barrel. The plurality of lenses are fitted into the inner circumference of the second barrel and are located on the image side of the first lens. A gap is provided between the outer circumference surface of the second barrel and the inner circumference surface of the first barrel. The gap allows radial outward movement throughout the entire optical axis direction of the second barrel. Since the lens unit in this document has a gap between the first barrel and the second barrel, even if the lens fitted into the inner circumference of the second barrel expands due to heat, it is less likely to receive force from the first barrel. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-203907 A Summary of the Invention [Problem to be solved by the invention]

[0004] If a gap is provided between the first and second barrels to avoid problems caused by expansion of components, the optical axis of the first lens held in the first barrel and the optical axis of the second lens held in the second barrel are likely to become misaligned.

[0005] In view of the above problems, an object of the present invention is to provide a lens unit that can prevent misalignment between the optical axis of a first lens held in a first barrel and the optical axis of a second lens held in a second barrel, while avoiding problems caused by expansion of components. [Means for solving the problem]

[0006] In order to solve the above problem, the lens unit of the present invention has a first lens, a second lens arranged on the image side of the first lens, a first barrel made of resin that houses the first lens, and a second barrel made of resin that houses the second lens and is held on the inner side of the first barrel, wherein the first barrel has an object-side facing portion that faces the object-side end portion of the second barrel from the outside in the radial direction in order to position the second barrel in the radial direction, and an image-side facing portion that faces the image-side portion of the second barrel from the outside in the radial direction in order to position the second barrel in the radial direction, wherein an object-side clearance is provided between the object-side facing portion and the second barrel in the radial direction, and an image-side clearance is provided between the image-side facing portion and the second barrel in the radial direction, and the object-side clearance is smaller than the image-side clearance.

[0007] In the present invention, the object-side facing portion for positioning the second lens barrel in the radial direction in the first lens barrel has an object-side clearance between it and the object-side end portion of the second lens barrel. Also, the image-side facing portion for positioning the second lens barrel in the radial direction in the first lens barrel has an image-side clearance between it and the image-side portion of the second lens barrel. Therefore, the second lens barrel is positioned on the first lens barrel in a state in which it is not perfectly positioned in all directions in the radial direction, but has a backlash. Therefore, even if the amount of deformation of the first lens barrel and the amount of deformation of the second lens barrel due to heat or moisture absorption differs due to differences in shape, thickness, or base material between the first and second lens barrels, the difference in the amount of deformation can be calculated by using the backlash (object clearance). The deformation of the first and second barrels due to heat or moisture can be prevented or suppressed from exerting a load on the second barrel from the first barrel and from the second barrel to the first barrel. This can prevent or suppress the load from being exerted on the first lens held in the first barrel and the second lens held in the second barrel.

[0008] According to the present invention, the object side end portion of the second lens barrel is positioned radially within the range of the object side clearance on the inner periphery side of the first lens barrel. That is, the second lens barrel is positioned radially between a state in which a part of the outer periphery of the object side end portion contacts the object side facing portion of the first lens barrel and a state in which the object side end portion does not contact the object side facing portion of the first lens barrel over the entire circumference with a gap of the object side clearance. Therefore, the radial wobble of the object side end portion of the second lens barrel is the wobble of the object side clearance and is very slight. Also, the image side end portion of the second lens barrel is positioned within the range of the image side clearance on the inner periphery side of the first lens barrel. That is, the second lens barrel is positioned between a state in which a part of the outer periphery of the image side end portion contacts the image side facing portion of the first lens barrel and a state in which the image side end portion does not contact the image side facing portion of the first lens barrel over the entire circumference with a gap of the image side clearance. Therefore, any wobble in the radial direction of the image side end portion of the second lens barrel is caused by the image side clearance and is very slight.

[0009] Furthermore, the second barrel is positioned at two points, an object side end portion and an image side portion, which are spaced apart in the optical axis direction. Therefore, the optical axis of the second lens held in the second barrel is prevented from tilting relative to the optical axis of the first lens held in the first barrel. Also, the object side clearance between the object side end portion of the second barrel close to the first lens and the first barrel is smaller than the clearance between the image side portion of the second barrel and the first barrel. This prevents wobbling on the object side more than on the image side. Therefore, it is easy to prevent the optical axis of the first lens held in the first barrel from being misaligned with the optical axis of the second lens held in the second barrel.

[0010] In the present invention, the image side clearance can be 10 μm or more and 15 μm or less on one side of the optical axis. If the value is in this range, rattling between the first and second lens barrels can be suppressed. In addition, when the first and second lens barrels are deformed due to heat or moisture absorption, the load from the first lens barrel to the second lens barrel and the load from the second lens barrel to the first lens barrel can be prevented or suppressed.

[0011] In the present invention, the first lens barrel can be made of crystalline plastic containing glass fiber, and the second lens barrel can be made of amorphous plastic. Crystalline plastic has better weather resistance than amorphous plastic. Therefore, if the first lens barrel located on the outer periphery side is made of crystalline plastic, it is easy to make the lens unit have good weather resistance. On the other hand, amorphous plastic has higher hygroscopicity and a larger thermal expansion coefficient than amorphous plastic. Therefore, a difference is likely to occur between the amount of deformation of the first lens barrel and the amount of deformation of the second lens barrel, which are deformed by heat or moisture absorption. In response to such a problem, in the present invention, the difference in the amount of deformation can be absorbed by the object side clearance and the image side clearance. Therefore, when the first lens barrel and the second lens barrel are deformed by heat or moisture absorption, the load applied from the first lens barrel to the second lens barrel and the load applied from the second lens barrel to the first lens barrel can be prevented or suppressed.

[0012] In the present invention, the lens has a plurality of lenses arranged on the image side of the second lens and housed in the second barrel, and the second lens and one of the plurality of lenses can be an amorphous plastic lens. The amorphous plastic lens has a larger thermal expansion coefficient than a glass lens and is easily deformed by heat. Here, if the amorphous plastic lens is housed in the second barrel made of amorphous plastic, the difference between the amount of deformation of the second barrel deformed by heat and the amount of deformation of the lens is small. Therefore, it is possible to prevent or suppress the load from being applied to the amorphous plastic lens from the second barrel due to the difference in the expansion coefficient.

[0013] In the present invention, the second lens is located next to the image side of the first lens, and an inter-lens adhesive layer is provided between a flange surface located on the outer periphery side of the image side lens surface of the first lens and a flange portion located on the outer periphery side of the object side lens surface of the second lens, and the inter-lens adhesive layer seals the space formed between the image side lens surface of the first lens and the object side lens surface of the second lens from the outer periphery side, and the inter-lens adhesive layer can be elastic. In this way, the inter-lens adhesive layer can prevent or suppress the intrusion of water vapor or the like into the space between the image side lens surface of the first lens and the object side lens surface of the second lens. In addition, since the inter-lens adhesive layer has elasticity, even if the position of the second lens held by the second lens barrel changes due to the deformation of the second lens barrel, the inter-lens adhesive layer deforms following the displacement. Therefore, the sealing of the space communicating between the image side lens surface of the first lens and the object side lens surface of the second lens can be maintained.

[0014] In the present invention, the first lens barrel includes a protruding portion protruding from the image side portion to the inner periphery side, and the second lens barrel includes an object side abutting portion that abuts against the protruding portion from the object side, and a lens 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 lens barrel fixing portion, and the lens barrel fixing portion includes a first plastic deformation portion that bends toward the outer periphery side, and a contact portion that contacts the protruding portion on the outer periphery side of the plastic deformation portion, and the inner periphery side end surface of the protruding portion can be the image side facing portion. In this way, the protruding portion of the second lens barrel is sandwiched from both sides in the optical axis direction by the object side abutting portion and the lens barrel fixing portion provided on the second lens barrel, so that the second lens barrel can be fixed to the first lens barrel in a state where it is positioned in the optical axis direction. Also, the lens barrel fixing portion includes a first plastic deformation portion that bends toward the outer periphery side, and a contact portion that contacts the protruding portion on the outer periphery side of the plastic deformation portion. Therefore, the lens barrel fixing part can be configured to form a first plastic deformation part by crimping a part of the second lens barrel to the outer periphery, and to have the contact part of the tip of the first plastic deformation part contact the protruding part. Here, the inner peripheral end face of the protruding part is the surface facing the image side. Therefore, an image side clearance exists between the inner peripheral end face of the protruding part and the second lens barrel. Therefore, when the protruding part of the second lens barrel is sandwiched between the object side abutment part and the lens barrel fixing part provided on the second lens barrel, it is possible to prevent the attitude of the second lens barrel with respect to the first lens barrel from being determined to be an attitude in which the second lens barrel abuts against the inner peripheral end face of the protruding part.

[0015] In the present invention, the first and second barrels include an inter-barrel adhesive layer provided between the outer peripheral surface of the first barrel and the inner peripheral surface of the second barrel between the object side facing portion and the image side facing portion in the optical axis direction, and the inter-barrel adhesive layer can be elastic. In this way, the second barrel and the first barrel can be fixed by the inter-barrel adhesive layer. In addition, since the inter-barrel adhesive layer has elasticity, the first barrel 3 and the second barrel 4 can be maintained fixed even if the first barrel 3 and the second barrel 4 are deformed due to heat or moisture absorption. Effect of the Invention

[0016] In the present invention, the second barrel is positioned on the first barrel in a state where it is not completely positioned in all radial directions, but has some wobble (object side clearance and image side clearance). Therefore, the difference in the amount of deformation between the first barrel and the second barrel due to heat or the like can be absorbed by the object side clearance and the image side clearance. In addition, the second barrel is positioned within the range of the object side clearance on the object side and the range of the image side clearance on the image side. Therefore, the wobble of the second barrel relative to the first barrel is very small. In addition, the second tube portion is positioned at two points, the object side end portion and the image side portion. Therefore, the optical axis of the second lens held by the second barrel is prevented from tilting relative to the optical axis of the first lens held by the first barrel. Furthermore, the object side clearance between the object side end portion of the second barrel close to the first lens and the first barrel is smaller than the clearance between the image side portion of the second barrel and the first barrel. This suppresses wobble on the object side more than on the image side. Therefore, it is easy to suppress misalignment between the optical axis of the first lens held by the first barrel and the optical axis of the second lens held by the second barrel. [Brief description of the drawings]

[0017] [Figure 1] FIG. 2 is a perspective view of the lens unit as viewed from the object side. [Diagram 2] FIG. 2 is a perspective view of the appearance of the lens unit as viewed from the image side. [Diagram 3] FIG. 2 is a cross-sectional view of the lens unit. [Figure 4] FIG. 2 is an exploded perspective view of the lens unit. [Diagram 5] FIG. 4 is a cross-sectional view of the first lens barrel. [Figure 6] FIG. 4 is a cross-sectional view of the second unit. [Figure 7] FIG. 2 is a perspective view of the second lens barrel as viewed from the object side. [Figure 8] FIG. 2 is a perspective view of a lens unit in the middle of assembly as viewed from the image side. [Figure 9] FIG. 4 is a partially enlarged cross-sectional view of the vicinity of an optical member facing portion. [Figure 10]FIG. 11 is a cross-sectional view of a lens unit according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a lens unit to which the present invention is applied will be described with reference to the drawings.

[0019] (Overall composition) 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 the lenses in the area between two dashed double-dashed lines (around the optical axis) are omitted.

[0020] 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, as the lens barrel 2, a first lens barrel 3 and a second lens barrel 4 held on the inner periphery side of the first lens barrel 3. The lens L1 is accommodated in the first lens barrel 3. The lenses L2 to L6 are accommodated in the second lens barrel 4. The lens L1 has a larger outer diameter than the lenses L2 to L6.

[0021] As shown in Fig. 1, lens L1 and first barrel 3 constitute a first unit 50. As shown in Fig. 4, lenses L2 to L6 and second barrel 4 constitute a second unit 60. In the following description, the direction along the optical axis L of lens L1 is defined as 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.

[0022] (optical system) As shown in Figs. 1 and 3, the lens L1 is a meniscus lens having a convex shape on the object side X1. As shown in Fig. 3, the lens L1 has an annular flange surface 11 that expands 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.

[0023] The lens L2 comprises a lens body portion 13 having a lens surface, and a flange portion 14 surrounding the lens body portion 13. The lens body portion 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. The end face of the flange portion 14 on the object side X1 is provided with an annular protrusion 15 protruding toward the object side X1. The annular protrusion 15 has an annular opposing surface at its tip that faces the flange surface 11 of the lens L1 in the optical axis direction X. The lens L1 has a flange surface 11 facing the second lens 15a. An inter-lens adhesive layer 12 is interposed between the flange surface 11 of the lens L1 and the facing surface 15a of the second lens. The inter-lens adhesive layer 12 has elasticity.

[0024] 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 protruding toward the object side X1 is provided on the end surface of the flange 17 on the image side X2. The fitting portion 18 includes a fitting tapered surface 18a surrounding the optical axis L and inclining toward the inner periphery toward the image side X2, and a fitting end surface 18b extending perpendicular to the optical axis L from the end of the fitting tapered surface 18a on the image side X2 toward the inner periphery.

[0025] 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 flange portion 14 of lens L2 and flange portion 17 of lens L3.

[0026] 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 that protrudes toward the image side X2 at the center. 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 includes a fitted portion tapered surface 22a that surrounds the optical axis L and is inclined toward the inner periphery 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 with each other. The fitting portion end face 18b of the lens L3 and the fitted portion end face 22b of the lens L4 are separated in the optical axis direction X. This positions the lens L3 in the radial direction with respect to the lens L4. Also, the image side X2 end face of the outer circumferential portion of the fitting portion 18 of the flange portion 17 of the lens L3 and the object side X1 end face of the outer circumferential portion of the fitted portion 22 of the flange portion 21 of the lens L4 are in contact in the optical axis direction X. Therefore, the lens L3 is stacked on the lens L4 in the optical axis direction X.

[0027] The lens L5 has a smaller outer diameter than the lenses L2, L3, L4, and L6. The lens L5 has 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 the 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 surface of the image side X2 of the contact portion 26 is continuous without a step with the outer periphery end of the lens surface 24a of the image side X2 of the lens body 24.

[0028] A resin holder 28 is disposed radially outward of the lens L5. The holder 28 is annular. An aperture 33 is disposed between the lens L4 and the lens L5. The aperture 33 is an annular sheet, and is sandwiched between the lens L4 and the holder 28.

[0029] The object-side lens L61 includes a lens body portion 35 having a lens surface, and a flange portion 36 surrounding the lens body portion 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 portion 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 portion 36 of the object-side lens L61 includes an annular end surface 38 on the image side X2 that is perpendicular to the optical axis L.

[0030] The image-side lens L62 includes a lens body 40 having a lens surface and a lens surrounding the lens body 40. The image-side lens L62 has a flange portion 41. The lens surface on the object side X1 of the image-side lens L62 is a curved surface protruding toward the object side X1, and the lens surface on the image side X2 is a curved surface protruding 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 portion 36 of the object-side lens L61 has a portion that protrudes from the image-side lens L62 to the outer periphery.

[0031] Here, the lens L2, the lens L3, the lens L4, the object side lens L61, and the image side lens L62 are all made of resin. In this example, the lens L2, the lens L3, the lens 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.

[0032] 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 barrel 4 on the object side X1 of lens L3.

[0033] Next, a plate-shaped optical member 10 is disposed on the image side X2 of the lens L6. The optical member 10 is a bandpass 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.

[0034] (Telescope tube) FIG. 4 is an exploded perspective view of the lens unit 1. FIG. 5 is a cross-sectional view of the first barrel. As shown in FIG. 3, the lens unit 1 includes a barrel 2, which is a first barrel 3 and a second barrel 4 held on the inner periphery of the first barrel 3. The first barrel 3 and the second barrel 4 are both made of resin. The lens L1 is housed in the first barrel 3. The lenses L2 to L6 and the holder 28 are housed in the second barrel 4. The second barrel 4 is held on the inner periphery of the first barrel 3.

[0035] (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 circumferential side of the lens L2, the lens L3, the lens L4, the holder 28, the lens L5, the lens L6, and the second lens barrel 4. As shown in FIG. 5, the first lens barrel 3 has an object side step 101 at an end portion on the object side X1 of the inner circumferential surface. The first lens barrel 3 also has an annular protrusion 102 at an 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 the inner circumferential surface.

[0036] The object side step 101 includes a support surface 105 facing the object side X1, an annular wall surface 106 extending from an inner peripheral end of the support surface 105 to the image side X2, and a peripheral wall surface 107 extending from an outer peripheral end of the support surface 105 to 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 an 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.

[0037] The first lens housing portion 108 includes a peripheral wall surface 107, a support surface 105, and a crimping 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 crimping portion 109 abuts against 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 crimping portion 109 is disposed at the end of the first barrel 3 on the object side X1. The first O-ring 7 is disposed between the support surface 105 and the crimped portion 109, and is compressed in the optical axis direction X, and is formed by, for example, thermal crimping, which bends the outer peripheral edge portion of the lens L1 toward the inner peripheral side. 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.

[0038] 4 and 5, the annular wall surface 106 is provided with object-side protrusions 110 that protrude radially inward at multiple locations in the circumferential direction. In this example, the object-side protrusions 110 are provided at three locations in the circumferential direction at equal angular intervals. The object-side protrusions 110 are object-side opposing portions that face the object-side end portion (positioning surface 223 described below) of the second lens barrel 4 from the radial outside in order to position the second lens barrel 4 in the radial direction.

[0039] 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 and 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.

[0040] 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 (an image side outer peripheral surface portion 227 described later) of the second lens barrel 4 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 image side X2 of the first lens barrel 3. The image side annular surface 112 is provided with four arc ribs 119 extending in the circumferential direction at four positions spaced apart in the circumferential direction.

[0041] As shown in FIG. 5 . The intermediate step 103 has an annular step flange surface 116 facing the object side X1, and an annular step wall surface 117 extending from the inner peripheral end of the step flange surface 116 to the image side X2. In this example, the intermediate step 103 is provided with notched grooves 118 at multiple locations in the circumferential direction, which extend in the optical axis direction X and divide the step flange surface 116 and the step wall surface 117 in the circumferential direction. The notched grooves 118 are provided at three locations in the circumferential direction at equal angular intervals. Therefore, the intermediate step 103 is divided into three in the circumferential direction by the notched grooves 118. The bottom surface of the notched groove 118 is the annular wall surface 106 extending from the inner peripheral end of the support surface 105 to the image side X2, and has a tapered shape in which the inner diameter dimension decreases toward the image side X2 in the portion where the intermediate step 103 is provided. 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 barrel 3 .

[0042] 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. That is, the first lens barrel 3 and the second lens barrel 4 have 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 and on the image side X2 of the protrusion 102.

[0043] Next, as shown in Fig. 5, the first barrel 3 has three steps 121, 122, and 123 on the object side of the outer circumferential surface, the outer diameter of which decreases stepwise toward the image side X2. Furthermore, these steps have a male thread 124 on the image side X2. Here, the shape of the outer circumferential surface of the first barrel 3 is not limited to this. For example, the outer circumferential surface of the first barrel 3 may be integrally provided with an outer frame for mounting the lens unit 1 on an external device.

[0044] (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 different from that of FIG. 3 by 90° 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 the lens L2, lens L3, lens L4, lens L5, holder 28, and lens L6 on the inner circumference side. The second lens barrel 4 also holds the optical member 10 at the end of the image side X2.

[0045] The second lens barrel 4 has an object-side step 201 at an end portion on the object side X1 of its inner circumferential surface. The second lens barrel 4 also has an image-side protrusion 202 that protrudes inwardly at an 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 protrusion 202 on its inner circumferential surface, 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 member holder 204 that holds the optical member 10 on the image side X2 of the image-side protrusion 202.

[0046] The object side step 201 includes a seating surface 205 facing the object side X1, an annular wall surface 206 extending from an inner peripheral end of the seating surface 205 to the image side X2, and a peripheral wall surface 207 extending from an outer peripheral end of the seating surface 205 to the object side X1. The annular wall surface 206 is a tapered surface whose inner diameter dimension decreases toward the image side X2. In the second barrel 4, the object side X1 of the object side step 201 is a second lens housing portion 208 that houses an outer peripheral edge portion of the lens L2.

[0047] The second lens housing portion 208 includes a peripheral wall surface 207, a seating surface 205, and a crimping portion 209. The peripheral wall surface 207 is a tapered surface that is inclined 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 fitting protrusions 210A that are pressed against the lens L2 at a plurality of positions spaced apart in the circumferential direction. In this example, the fitting protrusions 210A are provided at eight positions in the circumferential direction at equal angular intervals. The fitting protrusions 210A include a pressure-bonding surface 210a that is parallel to the optical axis L at the end on the inner periphery side. The pressure-bonding surfaces 210a of the plurality of fitting protrusions 210A are pressed against the lens L2 housed in the second lens housing portion 208 from the radially outer side to position the lens L2 in the radial direction. The seating surface 205 faces the end surface of the lens L2 on the image side X2 of the flange portion 14 from the image side X2. The crimped portion 209 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. The crimped portion 209 is a plastic deformation portion provided by thermal crimping or the like that bends the end portion of the second lens barrel 4 on the object side X1 toward the inner peripheral side. Here, as shown in Fig. 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 peripheral side of the crimped portion 209.

[0048] The annular wall surface 206 of the object side step 201 extends to the image side X2 and reaches the positioning step 203. As shown in FIG. 7, the annular wall surface 206 is provided with a fitting protrusion 210B, a fitting protrusion 210C, a fitting 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 fitting protrusions 210B to 210D and the guide protrusion 220 each protrude to the inner periphery side from a plurality of positions spaced apart in the circumferential direction. The fitting protrusions 210B to 210D have a pressure contact surface parallel to the optical axis L at the inner periphery end. The guide protrusion 220 has a guide surface parallel to the optical axis L at the inner periphery end.

[0049] As shown in Fig. 6, the positioning step 203 is located in an image side portion on the inner periphery side 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 an 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 an 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 to the object side X1 and extend in an arc shape in the circumferential direction.

[0050] 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 accommodated in the second lens barrel 4 in a state where it is 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. As a result, the laminate 44 is positioned in the radial direction. The image-side lens L62 of the lens L6 bonded to the object-side lens L61 is disposed on the inner circumferential side of the stepped portion peripheral wall surface 216. The stepped portion peripheral wall surface 216 faces the image-side lens L62 with a gap therebetween in the radial direction.

[0051] 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. The lens L3 is also 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 in a state in which 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 therebetween in the radial direction.

[0052] The second O-ring 8 is disposed on the object side X1 of the multiple guide protrusions 220, radially inside 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.

[0053] Next, the second barrel 4 has an annular positioning surface 223 at the end portion of the object side X1 of the outer circumferential surface. The positioning surface 223 is located radially outward of the second lens housing portion 208. The positioning surface 223 is a surface parallel to the optical axis L and faces radially outward. When the second barrel 4 is housed on the inner circumferential side of the first barrel 3, the positioning surface 223 faces the object side protrusion 110 (object side facing portion) of the first barrel 3. As shown in FIG. 3, an object side clearance C1 is provided between the object side protrusion 110 and the positioning surface 223.

[0054] As shown in FIG. 6, the second barrel 4 has an image side step 224 on the image side portion of the outer circumferential surface. The image side step 224 has 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 to the object side X1, and an image side outer circumferential surface portion 227 extending from the outer circumferential end of the annular surface 225 to 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 surface 213 of the second barrel 4. The outer circumferential surface of the second barrel 4 has an intermediate step 228 between the positioning surface 223 and the image side step 224, close to the positioning surface 223. The intermediate step 228 has 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 protruding portion 102 of the first barrel 3 from the object side X1.

[0055] As shown in FIG. 3, when the second lens barrel 4 is housed inside the first lens barrel 3, the image side step 224 is placed on a plurality of 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.

[0056] As shown in FIG. 2, the optical member holding portion 204 is provided on the image-side annular end surface 213 of the second barrel 4. The optical member holding portion 204 includes an optical member placement surface 231 (see FIG. 3) that surrounds the central hole of the second 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 from all sides. The four guide ribs 232 include two pairs of guide ribs 232 that face each other with the central hole of the second barrel 4 in between. In addition, the optical member The holding portion 204 includes an optical element facing portion 233 that extends from an end face on the image side X2 of one pair of guide ribs 232(1) toward the inner periphery and faces, from the image side X2, the optical element 10 placed on the optical element mounting surface 231. The optical element facing portion 233 includes a plastically deformed portion 234 (second plastically deformed portion) that is bent toward the inner periphery from the end face on the image side X2 of the guide rib 232, 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.

[0057] As shown in FIG. 8, the optical member facing portion 233 is formed by forming a plastically deformed portion 234 by crimping an optical member fixing crimping margin 241 provided on an end face on the image side X2 of one pair of guide ribs 232(1) to the inner periphery, and the facing portion 235 at the tip of the plastically deformed portion 234 faces the optical member 10. A gap is provided between the facing portion 235 and the optical member 10 in the optical axis direction X. The optical member 10 is fixed to the second lens barrel 4 by an adhesive applied to its outer periphery while being held by the optical member holding portion 204. While being held by the optical member holding portion 204, the four corners of the optical member 10 have their tip portions protruding from the second lens barrel 4 to the outer periphery and overlap with the protruding portion 102 of the first lens barrel 3 when viewed from the optical axis direction X. Here, the image side annular surface 112 of the protruding portion 102 is located closer to the object side X1 than the optical member 10. Therefore, the optical member 10 does not come into contact with the first lens barrel 3.

[0058] (Tube fixing part) 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 comes into contact with 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 has a plastically deformed portion 246 (first plastically deformed portion) bent toward the outer peripheral side of the end face of the image side X2 of the guide ribs 232. portion8, the barrel fixing part 245 has a barrel fixing caulking allowance 242 provided on the end face on the image side X2 of the other pair of guide ribs 232(2) crimped to the inner periphery to form the plastic deformation part 246, and a facing part 235 at the tip of the barrel fixing caulking allowance 242 faces the optical member 10.

[0059] 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 position. The lens barrel fixing portions 245 are provided at two locations on both sides of the optical member 10, and the optical member facing portions 233 are provided at two locations on both sides of the optical member 10, at positions different from the lens barrel fixing portions 245.

[0060] (Fixing the first and second telescope tubes) When fixing the first lens barrel 3 and the second lens barrel 4, first, lenses L2 to L6 are held by the second lens barrel 4. In this state, the optical member 10 is not held by the optical member holding portion 204 of the second lens barrel 4. Also, in this state, as shown in Fig. 8, a pair of optical member fixing caulking margins 241 and a 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.

[0061] 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 circumference side 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 circumference side 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 circumference side of the object side step 101 of the first lens barrel 3.

[0062] 3, an image side clearance C2 is provided between an inner peripheral end surface 113 (image side facing portion) of the protrusion 102 of the first barrel 3 for positioning the first barrel 3 and the second barrel 4 in the radial direction and an image side outer peripheral surface portion 227 of the image side step portion 224 of the second barrel 4. Also, an object side clearance C1 is provided between an object side protrusion 110 (object side facing portion) provided on the annular wall surface 106 of the object side step portion 101 of the first barrel 3 for positioning the first barrel 3 and the second barrel 4 in the radial direction and a positioning surface 223 of the object side end portion of the second 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.

[0063] Also, 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 gap in the radial direction 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 in the first lens barrel 3 with a very slight backlash, not in a state where it is completely positioned in all directions in the radial direction.

[0064] Next, the first barrel 3 and the second barrel 4 are held by a jig so that the object side X1 faces downward (see FIG. 8). Then, the optical member 10 is placed on the optical member holding portion 204 of the second barrel 4. Here, the image-side annular surface 112 of the protruding portion 102 of the first barrel 3 is located closer to the object side X1 than the optical member placement surface 231 of the second barrel 4. Therefore, the corners of the optical member 10 protruding from the second barrel 4 to the outer periphery side do not come into contact with the first barrel 3.

[0065] Thereafter, a crimping punch having a flat punch surface is brought close to the first lens barrel 3 and the second lens barrel 4 from above (the image side X2) to crimp the pair of optical member fixing crimping margins 241 and the pair of lens barrel fixing crimping margins 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 margins 241 have an inclined surface 241a on the side opposite to the optical axis L that is inclined from the tip toward the guide rib 232 toward the outer periphery. Therefore, by the crimping punch approaching the second lens barrel 4 from the optical axis direction X, the pair of optical member fixing crimping margins 241 form an optical member facing portion 233 including 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. Moreover, the surface of the pair of barrel fixing crimping margins 242 located on the optical axis L side is an inclined surface 242a that is inclined inward from the tip toward the guide rib 232. Therefore, the pair of barrel fixing crimping margins 242 are formed by the crimping punch into barrel fixing parts 245 that include plastically deformed parts 246 that are bent toward the outer periphery and contact parts 247 that come into contact with the protrusion 102 on the outer periphery side of the plastically deformed parts 246.

[0066] 9, a height dimension H1 between the optical member mounting surface 231 and the end face of the guide rib 232 on the image side X2 is longer than a thickness dimension D1 of the optical member 10. Also, the end face 119a (protruding portion side contact surface) of the arc rib 119 is located on the image side X2 of the image side 10a (optical member side facing surface) of the optical member 10 with which the facing portion 235 of the optical member facing portion 233 faces. Therefore, when the pair of optical member fixing crimping margins 241 and the pair of lens barrel fixing crimping margins 242 are crimped with a crimping punch having a flat punch surface, the lens barrel fixing crimping margins 242 are plastically deformed toward the outer periphery and the contact portion 247 at the tip of the crimping margin 242 contacts the end face 119 of the arc rib 119 of the first lens barrel 3. Although it is in contact with 19a, a gap is provided in the optical axis direction X between the optical member 10 and a facing portion 235 at the tip of the optical member fixing caulking allowance 241 that has been plastically deformed toward the inner periphery.

[0067] When the crimping is completed, the second barrel 4 is in a state where the protruding portion 102 of the first barrel 3 is sandwiched between the annular surface 225 of the image side step portion 224 and the barrel fixing portion 245. Therefore, the second barrel 4 is fixed to the first barrel 3. In addition, the optical member 10 is mechanically prevented from falling off the second barrel 4 to the image side X2 by the optical member facing portion 233. After that, an adhesive is applied to the outer periphery of the optical member 10. As a result, the optical member 10 is fixed to the optical member holding portion 204.

[0068] Thereafter, the first lens barrel 3 and the second lens barrel 4 are turned upside down. Then, adhesive is applied to the opposing surface 15a provided on the flange portion 14 of the lens L2 held by the second lens barrel 4. Also, 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 of the first lens barrel 3 via the first O-ring 7. Then, a crimped portion 109 that is bent inwardly is formed on the end portion of the object side X1 of the first lens barrel 3. When the crimped portion 109 is formed, the first O-ring 7 is compressed in the optical axis direction X between the end face of the image side X2 of the lens L1 and the support surface 105 of the first lens barrel 3. Here, the inter-lens adhesive layer 12 in which the adhesive has hardened 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 side in the optical axis direction X. The inter-lens adhesive layer 12 has elasticity.

[0069] (Action and effect) The lens unit 1 of this example includes a lens L1, a lens L2 arranged on the image side X2 of the lens L1, a first lens barrel 3 made of resin that houses the lens L1, and a second lens barrel 4 made of resin that houses the lens L2 and is held on the inner periphery side of the first lens barrel 3. The first lens barrel 3 includes an object-side protrusion 110 (object-side facing portion) that faces the end portion of the object side X1 of the second lens barrel 4 from the outside in the radial direction in order to position the second lens barrel 4 in the radial direction, and an inner periphery side end face 113 (image-side facing portion) that faces the image side portion of the second lens barrel 4 from the outside in the radial direction in order to position the second lens barrel 4 in the radial direction. An object-side clearance C1 is provided between the object-side protrusion 110 and the second lens barrel 4 in the radial direction. An image-side clearance C2 is provided between the inner periphery side end face 113 and the second lens barrel 4 in the radial direction. The object side clearance C1 is smaller than the image side clearance C2.

[0070] According to this example, the second barrel 4 is positioned in the first barrel 3 with a backlash, not in a state where it is completely positioned in all directions in the radial direction. Therefore, even if the amount of deformation of the first barrel 3 and the amount of deformation of the second barrel 4 due to heat or moisture absorption differs due to differences in shape, thickness, or base material between the first barrel 3 and the second barrel 4, the difference in the amount of deformation can be absorbed by the backlash (object side clearance C1 and image side clearance C2). This makes it possible to prevent or suppress 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 barrel and the second barrel are deformed due to heat or moisture absorption. Therefore, it is possible to prevent or suppress the load from being applied to the lens L1 held by the first barrel 3 and the lens L2 held by the second barrel 4.

[0071] Also, according to this example, the object side X1 end portion of the second lens barrel 4 is positioned radially within the range of the object side clearance C1 on the inner periphery side of the first lens barrel 3. That is, the second lens barrel 4 is positioned radially between a state in which a part of the outer periphery of the object side X1 end portion (positioning surface 223) is in contact with the object side protrusion 110 of the first lens barrel 3, and a state in which the object side X1 end portion is not in contact with the object side protrusion 110 of the first lens barrel 3 over the entire circumference with a gap of the object side clearance C1. Therefore, the radial wobble of the object side X1 end portion of the second lens barrel 4 is only wobble of the object side clearance C1, and is very slight. Also, the image side X2 end portion (image side outer peripheral surface portion 227) of the second lens barrel 4 is positioned radially between a part of the outer periphery of the object side X1 end portion (positioning surface 223) of the second lens barrel 4 with a gap of the image side clearance C1 on the inner periphery side of the first lens barrel 3. C2. That is, the second barrel 4 is positioned between a state in which a part of the outer periphery of the end portion of the image side X2 is in contact with the image side outer peripheral surface portion 227 of the first barrel 3 and a state in which the end portion of the image side X2 is not in contact with the image side outer peripheral surface portion 227 of the first barrel 3 over the entire circumference with a gap of the image side clearance C2. Therefore, the wobble in the radial direction of the end portion of the image side X2 of the second barrel 4 is the wobble of the image side clearance C2, which is very slight.

[0072] Furthermore, the second barrel 4 is positioned at two points, an end portion of the object side X1 and an image side portion, which are separated in the optical axis direction X. Therefore, the optical axis L of the lens L2 held by the second barrel 4 is prevented from tilting relative to the optical axis L of the lens L1 held by the first barrel 3. Also, the object side clearance C1 between the end portion of the object side X1 of the second barrel 4 close to the lens L1 and the first barrel 3 is smaller than the image side clearance C2 between the image side portion of the second barrel 4 and the first barrel 3. This prevents wobbling on the object side X1 from occurring more than on the image side X2. Therefore, it is possible to prevent the optical axis L of the lens L1 held by the first barrel 3 from shifting from the optical axis L of the lens L2 held by the second barrel 4.

[0073] In this example, the image side clearance C2 is 10 μm or more and 15 μm or less on one side of the optical axis L. A value in this range can suppress wobble between the first lens barrel 3 and the second lens barrel 4. In addition, when the first lens barrel and the second lens barrel are deformed due to heat or moisture absorption, the load applied from the first lens barrel 3 to the second lens barrel 4 and the load applied from the second lens barrel 4 to the first lens barrel 3 can be prevented or suppressed.

[0074] In this example, the first barrel 3 is made of crystalline plastic containing glass fiber. The second barrel 4 is made of amorphous plastic. Crystalline plastic has better weather resistance than amorphous plastic. Therefore, if the first barrel 3 located on the outer periphery side is made of crystalline plastic, the lens unit 1 can be made to have better weather resistance. On the other hand, amorphous plastic has higher hygroscopicity and a larger thermal expansion coefficient than amorphous plastic. Therefore, a difference is likely to occur between the amount of deformation of the first barrel 3 and the amount of deformation of the second barrel 4 caused by heat or moisture absorption. To address this problem, in this example, the difference between the amount of deformation of the first barrel 3 and the amount of deformation of the second barrel 4 can be absorbed by the object side clearance C1 and the image side clearance C2. This makes it possible to prevent or suppress 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 barrel and the second barrel are deformed due to heat or moisture absorption.

[0075] Next, this example has a plurality of lenses (lenses L3, L4, L5, and L6) arranged on the image side X2 of the lens L2 and housed in the second lens barrel 4. Among these lenses L2, L3, L4, L5, and L6, the lenses L2, L3, L4, and L6 are amorphous plastic lenses. The amorphous plastic lenses have good optical properties, but have a large thermal expansion coefficient compared to glass lenses, and are easily deformed by heat. Here, if the amorphous plastic lenses are housed in the second lens barrel 4 made of amorphous plastic, the difference between the amount of deformation of the second lens barrel 4 deformed by heat and the amount of deformation of the lenses (lenses L2, L3, L4, and L6) is small. Therefore, it is possible to prevent or suppress the load from being applied to these amorphous plastic lenses from the second lens barrel 4 due to the difference in the expansion coefficient.

[0076] In this example, lens L2 is located next to the image side X2 of lens L1, and an inter-lens adhesive layer 12 is provided between a flange surface 11 located on the outer periphery of the image-side lens surface of lens L1 and an annular protrusion 15 of a flange portion 14 located on the outer periphery of the object-side lens surface of lens L2. The inter-lens adhesive layer 12 seals the space V between the image-side lens surface and the object-side lens surface on the outer periphery in the optical axis direction X. The inter-lens adhesive layer 12 has elasticity. Therefore, it is possible to prevent or suppress the intrusion of water vapor and the like into the space V between lenses L1 and L2. In addition, because inter-lens adhesive layer 12 has elasticity, even if the position of lens L2 held by second barrel 4 changes due to deformation of second barrel 4 or the like, inter-lens adhesive layer 12 deforms in response to the displacement, and can maintain the sealing of space V.

[0077] In this example, the first lens barrel 3 has a protruding portion 102 protruding from the image side portion to the inner periphery side. The second lens barrel 4 has an image side step portion 224 (object side abutment portion) that abuts against the protruding portion 102 from the object side X1, and a lens barrel fixing portion 245 that contacts the protruding portion 102 from the image side X2 and sandwiches the protruding portion 102 between the image side step portion 224. The lens barrel fixing portion 245 has a plastic deformation portion 246 that is bent toward the outer periphery side, and a contact portion 247 that contacts the protruding portion 102 on the outer periphery side of the plastic deformation portion 234. The inner periphery side end surface 113 of the protruding portion 102 is an image side facing surface that faces the image side outer periphery surface portion 227 of the second lens barrel 4 with an image side clearance C2. According to this example, the protrusion 102 of the first barrel 3 is sandwiched from both sides in the optical axis direction X by the image side step 224 and the barrel fixing part 245 provided on the second barrel 4, so that the second barrel 4 can be fixed to the first barrel 3 while being positioned in the optical axis direction X. Also, the barrel fixing part 245 can be formed by forming a plastic deformation part 246 by crimping a part of the second barrel 4 on the outer periphery side, and the contact part 247 at the tip of the plastic deformation part 246 is brought into contact with the protrusion 102. Here, the inner peripheral side end face 113 of the protrusion 102 faces the image side outer peripheral surface part 227 of the second barrel 4 with an image side clearance C2 therebetween. Therefore, when the protrusion 102 of the first lens barrel 3 is clamped by the image side step 224 and the lens barrel fixing portion 245 provided on the second lens barrel 4, it is possible to prevent the attitude of the second lens barrel 4 relative to the first lens barrel 3 from being determined in a state in which the second lens barrel 4 abuts against the inner end face 113 of the protrusion 102.

[0078] (Modification) 10 is a cross-sectional view of a modified lens unit. In the modified lens unit 1A, the first lens barrel 3 and the second lens barrel 4 are fixed with an adhesive. Therefore, the second lens barrel 4 does not have a lens barrel fixing part 245. The other configuration of the lens unit 1A is the same as that of the lens unit 1.

[0079] As shown in FIG. 10, the lens unit 1A includes an inter-barrel adhesive layer provided between the outer peripheral surface of the first lens barrel 3 and the inner peripheral surface of the second lens barrel 4. The inter-barrel adhesive layer is located between the object-side protrusion 110 (object-side facing portion) and the inner peripheral end surface 113 (image-side facing portion) of the protrusion 102 in the optical axis direction X. That is, when the second lens barrel 4 is held by the first lens barrel 3, the first lens barrel 3 and the second lens barrel 4 have a radial gap between the protrusion 102 and the object-side step 101 in the optical axis direction X. The inter-barrel adhesive layer is provided in the gap. The inter-barrel adhesive layer 250 has elasticity.

[0080] When providing the inter-barrel adhesive layer 250, before inserting the second barrel 4 into the inner periphery of the first barrel 3, adhesive is applied to the step flange surface 116 of the intermediate step 103 of the first barrel 3. When the second barrel 4 is inserted into the inner periphery of the first barrel 3, the adhesive applied to the step flange surface 116 of the intermediate step 103 of the first barrel 3 spreads to the step wall surface 117. Therefore, the inter-barrel adhesive layer 250 is formed between the step flange surface 116 of the intermediate step 103 of the first barrel 3 and the annular surface 229 of the intermediate step 228 of the second barrel 4. The inter-barrel adhesive layer 250 is also formed between the step wall surface 117 of the intermediate step 103 of the first barrel 3 and the object side outer periphery portion 226 of the second barrel 4.

[0081] According to this example, the first lens barrel 3 and the second lens barrel 4 can be fixed together by the inter-barrel adhesive layer 250. In addition, because the inter-barrel adhesive layer 250 has elasticity, the first lens barrel 3 and the second lens barrel 4 can be maintained fixed together even if the first lens barrel 3 and the second lens barrel 4 are deformed due to heat or moisture absorption.

[0082] Here, the present technology can have the following configurations. (1) a first lens, a second lens disposed on the image side of the first lens, and the first lens and a second barrel made of resin that houses the second lens and is held on the inner peripheral side of the first barrel, wherein the first barrel has an object-side facing portion that faces an object-side end portion of the second barrel from the outside in the radial direction in order to position the second barrel in the radial direction, and an image-side facing portion that faces an image-side portion of the second barrel from the outside in the radial direction in order to position the second barrel in the radial direction, an object-side clearance is provided between the object-side facing portion and the second barrel in the radial direction, and an image-side clearance is provided between the image-side facing portion and the second barrel in the radial direction, and the object-side clearance is smaller than the image-side clearance.

[0083] (2) The lens unit described in (1), wherein the image side clearance is 10 μm or more and 15 μm or less on one side.

[0084] (3) The lens unit described in (1) or (2), wherein the first barrel is made of a crystalline plastic containing glass fiber, and the second barrel is made of an amorphous plastic.

[0085] (4) The lens unit described in (3) has a plurality of lenses arranged on the image side of the second lens and housed in the second barrel, the second lens and one of the plurality of lenses being an amorphous plastic lens.

[0086] (5) The lens unit described in any of (1) to (4), characterized in that the second lens is located adjacent to the image side of the first lens, 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 a space formed between the image-side lens surface of the first lens and the object-side lens surface of the second lens from the outer periphery side, and the inter-lens adhesive layer has elasticity.

[0087] (6) A lens unit described in any of (1) to (5), characterized in that the first lens barrel has a protrusion protruding from an image side portion to the inner peripheral side, the second lens barrel has an object side abutment portion that abuts against the protrusion from the object side, and a lens barrel fixing portion that contacts the protrusion from the image side and sandwiches the protrusion between the object side abutment portion and the lens barrel fixing portion, the lens barrel fixing portion has a first plastic deformation portion that bends toward the outer peripheral side, and a contact portion that contacts the protrusion on the outer peripheral side of the plastic deformation portion, and the inner peripheral end face of the protrusion is the image side facing portion.

[0088] (7) A lens unit described in any one of (1) to (5), characterized in that the first barrel and the second barrel have an inter-barrel adhesive layer provided between the outer peripheral surface of the first barrel and the inner peripheral surface of the second barrel between the object side facing portion and the image side facing portion in the optical axis direction, and the inter-barrel adhesive layer has elasticity. [Explanation of symbols]

[0089] Reference Signs List 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 body portion, 14...flange portion, 15...annular protrusion, 15a...opposing surface, 16...lens body portion, 17...flange portion, 18...fitting portion, 18a...fitting portion tapered surface, 18b...fitting portion end surface, 20...lens 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... flange 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... laminate, 50... first unit, 60... second unit, 101... object side step portion, 102... protruding portion, 103... intermediate step portion, 105... support surface, 106... annular wall surface, 107... peripheral wall surface , 108...first lens housing portion, 109...crimping 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, 124...male thread, 201...object side step, 202...image side protrusion portion, 203...positioning step portion, 204...optical member holding portion, 205...seat surface, 206...annular wall surface, 207...circumferential wall surface, 208...second lens housing portion, 209...crimping portion, 210a...pressure bonding surface, 210A to 210D...fitting 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 peripheral surface portion, 227...image side outer peripheral surface portion, 228...intermediate step portion, 229...annular surface, 231...optical member mounting portion, 232...guide rib, 233...optical member facing portion, 234...plastic deformation portion (second plastic deformation portion), 235...facing portion, 241...optical member fixing caulking portion, 241a...inclined surface, 242...lens barrel fixing caulking portion, 242a...inclined surface, 24 5...lens barrel fixing portion, 246...plastically deformed portion (first plastically deformed portion), 247...contact portion, 250...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...lens, 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 first lens; A second lens disposed on the image side of the first lens; a first lens barrel made of resin that houses the first lens; a second lens barrel made of resin that houses the second lens and is held on the inner peripheral side of the first lens barrel; having the first lens barrel includes an object-side facing portion that faces an object-side end portion of the second lens barrel from the outside in the radial direction in order to position the second lens barrel in the radial direction, and an image-side facing portion that faces an image-side portion of the second lens barrel from the outside in the radial direction in order to position the second lens barrel in the radial direction, an object-side clearance is provided between the object-side facing portion and the second barrel in the radial direction, an image-side clearance is provided between the image-side facing portion and the second barrel in the radial direction, 13. A lens unit, comprising: a first lens unit having a first aperture and a second lens unit;

2. 2. The lens unit according to claim 1, wherein the image side clearance is 10 μm or more and 15 μm or less on one side.

3. the first lens barrel is made of a crystalline plastic containing glass fiber; The lens unit according to claim 1 , wherein the second barrel is made of amorphous plastic.

4. a plurality of lenses disposed on the image side of the second lens and housed in the second lens barrel; 4. The lens unit according to claim 3, wherein the second lens and one of the plurality of lenses are amorphous plastic lenses.

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

6. the first barrel includes a protruding portion protruding from an image side portion to an inner peripheral side, the second barrel includes an object-side contact portion that contacts 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 contact portion and the second barrel fixing portion, the lens barrel fixing portion includes a first plastic deformation portion bent toward an outer periphery and a contact portion that contacts the protrusion on the outer periphery side of the plastic deformation portion, 2. The lens unit according to claim 1, wherein an inner peripheral end face of the protruding portion is the image-side facing portion.

7. the first lens barrel and the second lens barrel include an inter-barrel adhesive layer provided between an outer circumferential surface of the first lens barrel and an inner circumferential surface of the second lens barrel between the object side facing portion and the image side facing portion in the optical axis direction, The lens unit according to claim 1 , wherein the inter-lens barrel adhesive layer has elasticity. to.

Images