Lens unit

Abstract

The lens unit includes: a plurality of lenses arranged along an optical axis of the lens unit, the plurality of lenses including at least one resin lens; a lens barrel accommodating the plurality of lenses, the lens barrel including a fitting receiving portion; and a pressing member configured to press the plurality of lenses housed in the lens barrel. The at least one resin lens includes a fitting portion that can be fitted to the fitting receiving portion. The fitting portion and the fitting receiving portion each have: a tapered cross-sectional shape along the optical axis; and a shape of a circle centered on the optical axis in a plane orthogonal to the optical axis. The diameter of the circle varies depending on the position on the optical axis.

Description

Technical Field

[0001] The present disclosure relates to a lens unit. Background Art

[0002] A lens unit is known, which includes a plurality of lenses arranged along an optical axis, including at least one resin lens; a lens barrel accommodating the plurality of lenses; and a pressing member for pressing the plurality of lenses accommodated in the lens barrel. This lens unit is used in a camera mounted on a moving body such as a car or a drone, or in a surveillance camera set in a building.

[0003] In order to suppress the performance change of the lens unit caused by the deformation of the resin lens, the following structure is proposed: by forming the resin lens by a lens portion serving as a lens and a flange portion on the outside thereof, stress can be concentrated on the flange portion (for example, Patent Document 1).

[0004] However, the structure of Patent Document 1 may cause a change in the performance of the lens unit due to a change in its state from the state at the time of assembly.

[0005] For example, Patent Document 1 discloses a structure of a lens unit including a lens barrel accommodating a plurality of lenses, the plurality of lenses including a first lens arranged on the object side and a second lens adjacent to the first lens on the image side. In addition, in the lens unit, an elastic member in contact with the first lens and the second lens is provided between the first lens and the second lens.

[0006] However, in the configuration of the lens unit disclosed in Patent Document 1, there are cases where the performance of the lens unit varies due to changes in the shapes or positions of the plurality of lenses.

[0007] Citation list

[0008] Patent Literature

[0009]

PTL1

[0010] Technical issues

[0011] An object of the present invention is to provide a lens unit capable of suppressing a change in state during assembly.

[0012] Solutions to the problem

[0013] A lens unit includes: a plurality of lenses arranged along the optical axis of the lens unit, the plurality of lenses including at least one resin lens; a lens barrel for storing the plurality of lenses, the lens barrel including a fitting receiving portion; and a pressing member configured to press the plurality of lenses stored in the lens barrel. The at least one resin lens includes a fitting portion that can be fitted into the fitting receiving portion. The fitting portion and the fitting receiving portion each have: a conical cross-sectional shape along the optical axis; and a circular shape centered on the optical axis in a plane orthogonal to the optical axis. The diameter of the circle varies depending on the position on the optical axis.

[0014] A lens unit includes: a plurality of lenses arranged along the optical axis of the lens unit, the plurality of lenses including at least two resin lenses; a lens barrel to accommodate the plurality of lenses; and a pressing member configured to press the plurality of lenses accommodated in the lens barrel. The at least two resin lenses include: a first resin lens; and a second resin lens adjacent to the first resin lens. The first resin lens includes a fitting receiving portion. The second resin lens includes a fitting portion that can be fitted into the fitting receiving portion. The fitting portion and the fitting receiving portion each have: a conical cross-sectional shape along the optical axis; and a circular shape centered on the optical axis in a plane orthogonal to the optical axis. The diameter of the circle varies depending on the position on the optical axis.

[0015] Effects of the Invention

[0016] The embodiments of the present disclosure realize a lens unit which reduces or prevents a change in its state from a state at the time of assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings are intended to describe embodiments of the present disclosure and should not be interpreted as limiting the scope thereof. Unless explicitly noted, the accompanying drawings should not be considered to be drawn to scale. Moreover, throughout the several views, the same or similar reference numerals represent the same or similar components.

[0018] [ Figure 1 ]

[0019] Figure 1 It is a longitudinal sectional view of the lens unit of the first embodiment.

[0020] [ Figure 2 ]

[0021] Figure 2 yes Figure 1 A plan view of a resin lens included in a lens unit.

[0022] [ Figure 3 ]

[0023] Figure 3It is a longitudinal sectional view of a lens unit of a comparative example.

[0024] [ Figure 4 ]

[0025] Figure 4 It is a longitudinal sectional view of the lens unit of the second embodiment.

[0026] [ Figure 5 ]

[0027] Figure 5 yes Figure 4 A plan view of a second resin lens included in the lens unit.

[0028] [ Figure 6 ]

[0029] Figure 6 It is a longitudinal sectional view of the lens unit of the third embodiment.

[0030] [ Figure 7 ]

[0031] Figure 7 yes Figure 6 A plan view of a resin lens included in a lens unit. DETAILED DESCRIPTION

[0032] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0033] In describing the embodiments shown in the drawings, specific terms are used for clarity. However, the disclosure of this specification is not intended to be limited to the specific terms selected, and it should be understood that each specific component includes all technical equivalents having similar functions, operating in a similar manner and achieving similar results.

[0034] A lens unit according to an embodiment of the present disclosure is described in detail with reference to the accompanying drawings.

[0035] In order to realize the above technical ideas, the lens unit 1000 of the embodiment of the present invention is described below, but the present invention is not limited to the following embodiments. For example, in the following description, the size, material, shape, relative position of the configured components, etc. of the components are used as examples for description. Unless otherwise specified, the scope of the present disclosure is not limited to this. For example, in order to illustrate in the accompanying drawings, the size of these components and the relative positions of these components may be exaggerated. In the following description given with reference to the accompanying drawings, the same figure marks represent the same components, and repeated descriptions may be appropriately simplified or omitted.

[0036] First embodiment

[0037] Configuration Example of Lens Unit 100

[0038] Reference Figure 1 and Figure 2 , the structure of the lens unit 100 of the first embodiment is described. Figure 1 It is a longitudinal sectional view showing the structure of the lens unit 100 . Figure 2 yes Figure 1 1 is a plan view of the resin lens 2 in the lens unit 100 as viewed from the negative direction of the Z axis (hereinafter referred to as the −Z direction). Figure 2 The direction indicated by the arrow Z in is the positive direction along the Z axis (hereinafter referred to as the +Z direction). The -Z direction is the direction opposite to the +Z direction.

[0039] like Figure 1 As shown, the lens unit 100 includes a lens barrel 1 , a resin lens 2 , a light shielding portion 3 , a spacer ring 4 , a glass lens 5 , and a pressing member 6 .

[0040] The lens barrel 1 has a fitting receiving portion B that accommodates a resin lens 2 and a glass lens 5. The material of the lens barrel 1 is metal, such as aluminum. However, the material of the lens barrel 1 may be resin.

[0041] In this embodiment, the lens barrel 1 is formed in a hollow substantially cylindrical shape. The lens barrel 1 accommodates a resin lens 2, a light shielding portion 3, a spacer ring 4, and a glass lens 5 in order therein. The lens barrel 1 has a small diameter portion 11 and a contact surface 12.

[0042] The small diameter portion 11 is annularly provided on a part of the inner side of the lens barrel 1. The inner diameter of the small diameter portion 11 is smaller than the outer diameter of the resin lens 2 accommodated in the lens barrel 1. The small diameter portion 11 has a fitting receiving portion B.

[0043] The fitting receiving portion B has a tapered shape, and its diameter changes with respect to the optical axis C depending on the position along the direction of the optical axis C. In other words, the fitting receiving portion B has a tapered cross-sectional shape on the optical axis C, and has a circular shape with respect to the optical axis C in a plane orthogonal to the optical axis C, and the diameter of the circle varies depending on the position on the optical axis. In the present embodiment, the fitting receiving portion B has a substantially conical shape in which the diameter of the circle with respect to the optical axis C increases toward the direction of the image formed by the lens unit 100 (i.e., the -Z direction).

[0044] The contact surface 12 of the small diameter portion 11 is a surface substantially perpendicular to the optical axis C of the lens unit 100 . The resin lens 2 housed in the lens barrel 1 is in contact with the contact surface 12 .

[0045] The resin lens 2 and the glass lens 5 correspond to a plurality of lenses arranged along the optical axis C.

[0046] In this embodiment, the resin lens 2 is made of resin. The glass lens 5 is made of glass. However, the lens unit 100 may include a resin lens different from the resin lens 2 instead of the glass lens 5 .

[0047] At least a portion of the outer periphery of the resin lens 2 is formed in a substantially cylindrical shape. The outer diameter of the substantially cylindrical shape of the resin lens 2 is smaller than the inner diameter of the lens barrel 1. Thus, there is a gap (air layer) between the resin lens 2 and the lens barrel 1, and the resin lens 2 is accommodated in the lens barrel 1.

[0048] The resin lens 2 has a lens portion 21 and a flange portion 22. The lens portion 21 has an optical axis C at the center thereof, and functions as a lens for light incident on the resin lens 2.

[0049] The flange portion 22 is located outside the lens portion 21. The flange portion 22 does not function as a lens for light incident on the resin lens 2. The flange portion 22 includes a fitting portion A, a first portion 221, and a second portion 222.

[0050] The fitting portion A can be embedded in the fitting receiving portion B. The diameter of the conical shape of the fitting portion A is slightly smaller than the diameter of the conical shape of the fitting receiving portion B as a whole. The fitting portion A is formed on the surface of the flange portion 22, which is closer to the object (than other surfaces of the flange portion) in the direction toward the object (i.e., in the +Z direction). The fitting portion A has a conical shape whose diameter centered on the optical axis C varies according to the position in the direction of the optical axis C. In other words, the cross-sectional shape of the fitting portion A in the direction of the optical axis C is a cone, and has a circle centered on the optical axis C in a plane orthogonal to the optical axis C, and the diameter of the circle varies depending on the position on the optical axis. In the present embodiment, the fitting portion A has a roughly conical shape in which the diameter of the circle centered on the optical axis C increases toward the -Z direction.

[0051] The first portion 221 is an annular portion in contact with the lens barrel 1. The lens barrel 1 is an example of a first member. The first portion 221 is a surface of the flange portion 22 formed on the +Z direction side and substantially perpendicular to the optical axis C. The first portion 221 is in contact with an annular region of the surface of the small diameter portion 11 of the lens barrel 1 substantially perpendicular to the optical axis C.

[0052] The second portion 222 is an annular portion, and abuts against the spacer ring 4 on the opposite side of the first portion 221 along the optical axis C. The spacer ring 4 is an example of a second component. The second portion 222 is a surface of the flange portion 22 formed on the -Z direction side and substantially orthogonal to the optical axis C. The spacer ring 4 has a surface substantially orthogonal to the optical axis C, and the surface abuts against the second portion 222 in an annular region via the light shielding portion 3.

[0053] like Figure 2As shown in FIG. 1 , in the resin lens 2, the second portion 222 is located between the fitting portion A and the first portion 221 in a direction orthogonal to the optical axis C. In other words, the positional relationship among the fitting portion A, the first portion 221, and the second portion 222 is as follows: the fitting portion A, the second portion 222, and the first portion 221 in the order of leaving the optical axis C.

[0054] like Figure 1 As shown, the light shielding part 3 shields the disturbance light and the undesired reflected light incident on the lens unit 100. For example, the light shielding part 3 is a sheet-like component with a thickness of about several tens of μm. The material of the light shielding part 3 is not particularly limited, and resin or metal can be used. In addition, the light shielding part 3 may not be used.

[0055] The spacer ring 4 limits the distance between the resin lens 2 and the glass lens 5 to a predetermined distance.

[0056] The spacer ring 4 is formed in a substantially cylindrical shape and is housed in the lens barrel 1 while supporting the glass lens 5 therein. The outer diameter of the spacer ring 4 is slightly smaller than the inner diameter of the lens barrel 1. Thus, the spacer ring 4 is mounted on the lens barrel 1. The material of the spacer ring 4 is not limited to any specific material, and resin or metal may be used.

[0057] The pressing member 6 presses the resin lens 2 and the glass lens 5 housed in the lens barrel 1. The pressing member 6 has a first threaded portion at a portion of its exterior. The pressing member 6 presses the spacer ring 4 supporting the resin lens 2, the light shielding portion 3, and the glass lens 5 by connecting the first threaded portion of the pressing member 6 to the second threaded portion on the inner side of the lens barrel 1 and the end portion on the -Z direction side of the lens barrel 1. By pressing the pressing member 6 of the spacer ring 4, the resin lens 2, the light shielding portion 3, and the glass lens 5 are fixed to the lens barrel 1. The material of the pressing member 6 is not limited to any specific material, but resin or metal can be used.

[0058] Operation of the lens unit 100

[0059] Hereinafter, the operation of the lens unit and the method of assembling the lens unit 100 will be described.

[0060] When assembling the lens unit 100 , first, the resin lens 2 is inserted into the lens barrel 1 . The first portion 221 of the resin lens 2 comes into contact with the contact surface 12 of the small diameter portion 11 of the lens barrel 1 .

[0061] Before the pressing force is applied by the pressing member 6, a slight gap exists between the fitting portion A of the resin lens 2 and the fitting receiving portion B of the lens barrel 1. By providing such a gap, the resin lens 2 is positioned in the radial direction.

[0062] Then, the spacer ring 4 is inserted into the lens barrel 1. The spacer ring 4 has a surface substantially perpendicular to the optical axis C, and the surface contacts the second portion 222 of the resin lens 2 via the light shielding portion 3. Then, the spacer ring 4 supports the glass lens 5 inside.

[0063] Next, by connecting the first threaded portion of the pressing member 6 to the second threaded portion of the lens barrel 1, a pressing force in the direction of the optical axis C is applied to the resin lens 2. The pressing force is transmitted through the components housed in the lens barrel 1 and then applied to the resin lens 2. In the resin lens 2, a pressing force F is applied to the second portion 222 from the spacer ring 4. As a reaction to the pressing force F, a resistance force N in the opposite direction to the pressing force F is generated in the first portion 221 of the resin lens 2.

[0064] The second portion 222 is closer to the optical axis C than the first portion 221. At the relative position of the first portion 221 and the second portion 222, moments M1 and M2 are applied to the resin lens 2. The resin lens 2 is deformed by the moments M1 and M2, so that the center of the resin lens 2 protrudes in the +Z direction.

[0065] The deformation of the resin lens 2 fills the gap between the fitting portion A and the fitting receiving portion B, so that the fitting portion A and the fitting receiving portion B are in contact with each other. Through the contact between the fitting portion A and the fitting receiving portion B, the resistance N2 from the fitting portion A acts on the resin lens 2, and the resistance N is balanced with the moment M1 and the moment M2. By balancing the resistance N with the moments M1 and M2 in this way, the deformation of the resin lens 2 caused by the ambient temperature of the lens unit 100, the passage of time, etc. can be suppressed.

[0066] The larger the taper angle of the fitting portion A and the fitting receiving portion B (that is, the larger the inclination angle of each surface of the fitting portion A and the fitting receiving portion B relative to the optical axis C), the closer the action direction of the resistance N2 (the direction of the resistance N2) is to the direction parallel to the optical axis C. In this structure, since the relatively small resistance N2 can be balanced with the moments M1 and M2, it is preferred that the inclination angle of each surface of the fitting portion A and the fitting receiving portion B relative to the optical axis C is relatively large.

[0067] Comparative Example

[0068] Hereinafter, comparative examples of the lens unit will be described.

[0069] In recent years, lens units using resin lenses have been increasingly used in vehicle applications that require performance in a wide temperature range. As such lens units, there is a known lens unit that supports lenses from both sides and fixes them to a lens barrel.

[0070] The shape of the resin lens changes significantly with temperature or over time. Therefore, during assembly, that is, when manufacturing the lens unit, it is preferred to set the pressure applied to the resin lens as high as possible to prevent insufficient pressure during use of the lens unit. However, since the resin lens is softer than the glass lens, the amount of deformation increases when the pressing force is large. The deformation of the lens changes the performance of the lens unit. Therefore, a lens unit is needed that can maintain the pressing force applied to the resin lens during use and can suppress performance changes caused by the deformation of the resin lens.

[0071] Figure 3 1 is a longitudinal sectional view showing the structure of a lens unit 100X of a comparative example. The lens unit 100X includes a first light shielding portion 7, a resin lens 2X, a first lens 5X, a second light shielding portion 8, a spacer ring 4X, a second lens 9, and a pressing member 6X. These members are arranged in this order along the optical axis CX and housed in a lens barrel 1X.

[0072] The resin lens 2X and the first lens 5X are made of resin. The second lens 9 is made of glass. At least a portion of the outer periphery of the resin lens 2X and the first lens 5X is formed into a roughly cylindrical shape. The roughly cylindrical outer diameter of the resin lens 2X and the first lens 5X is smaller than the inner diameter of the lens barrel 1X. Thus, there is a gap (air layer) between the resin lens 2X and the first lens 5X and the lens barrel 1X, and the resin lens 2X and the first lens 5X are stored in the lens barrel 1.

[0073] The resin lens 2X has a first lens portion 21X and a first flange portion 22X. The first lens portion 21X is located at the central portion of the resin lens 2X and functions as a lens for light incident on the resin lens 2X. The first flange portion 22X is located outside the first lens portion 21X. The first flange portion 22X has a first surface (i.e., a surface on the +Z side) that presses the lens barrel 1X on the +Z side in the direction along the optical axis CX. The first flange portion 22X has a second surface (i.e., a surface on the -Z side) on the -Z side that presses the first lens 5X in the direction along the optical axis CX.

[0074] The first lens 5X includes a second lens portion 51X and a second flange portion 52X. The second lens portion 51X is located at the center of the first lens 5X and functions as a lens for light incident on the first lens 5X. The second flange portion 52X is located outside the second lens portion 51X. The second flange portion 52X includes a first surface on the +Z side (i.e., the surface on the +Z side) and presses the resin lens 2X in the direction along the optical axis CX. The second flange portion 52X includes a second surface on the -Z side (i.e., the surface on the -Z side) and presses the spacer ring 4X in the direction along the optical axis CX.

[0075] The spacer ring 4X is formed into a substantially cylindrical shape and supports the second lens 9 inside. The spacer ring 4X limits the first lens 5X and the second lens 9 to a predetermined interval (distance). The outer diameter of the spacer ring 4X is slightly smaller than the inner diameter of the lens barrel 1X. Thus, there is a small gap between the spacer ring 4X and the lens barrel 1X, and the spacer ring 4X can be embedded in the lens barrel 1X.

[0076] The first light shielding portion 7 and the second light shielding portion 8 respectively block disturbance light incident on the lens unit 100X and undesired light reflected within the lens unit 100X.

[0077] The pressing member 6X has a first threaded portion at a portion of its exterior. The pressing member 6X presses the components housed in the lens barrel 1X by engaging the first threaded portion with a second threaded portion formed inside the lens barrel 1X.

[0078] When assembling the lens unit 100X, before inserting the resin lens 2X into the lens barrel 1X, first insert the first light shielding portion 7 into the lens barrel 1X, make the first light shielding portion 7 contact with the lens barrel 1X, and make the first light shielding portion 7 interposed between the lens barrel 1X and the resin lens 2X. Thus, the resin lens 2X is positioned in the direction along the optical axis CX. The second light shielding portion 8 and the spacer ring 4X supporting the second lens 9 are also sequentially inserted into the lens barrel 1X.

[0079] The radial positioning of each component is achieved by the engagement of each component with any one of the lens barrel 1X, the first lens 5X, and the spacer ring 4X. The first lens 5X is engaged with the resin lens 2X for positioning, and the second lens 9 is engaged with the spacer ring 4X for positioning. Among these components, the components other than the first lens 5X and the second lens 9 are installed in the lens barrel 1X for positioning.

[0080] After the components are positioned, they are pressed by the pressing member 6X, and the components housed in the lens barrel 1X are fixed to the lens barrel 1X.

[0081] Lens deformation during assembly of lens unit 100X

[0082] When the lens unit 100X is assembled, if a pressing force is applied to the lens, the lens is deformed. More specifically, the lens is compressed by pressing in the direction along the optical axis CX. If the deformation caused by this compression is unbalanced with the moment applied to the lens, the lens may bend.

[0083] The deformation of the lens is determined by the moment of inertia of the section according to the lens shape and the moment applied to the lens. Since the moment of inertia of the section depends on the thickness of the lens, the thinner the lens is, the greater the deformation of the lens due to its deflection becomes. The deflection of the lens prevents the flange portion from completely absorbing the deformation of the lens, thus deforming the lens portion.

[0084] It is also possible to adjust the application position of the pressing force to each lens and the lens barrel 1X to cancel the moment, thereby reducing the lens deformation. However, due to manufacturing errors of the lens and the lens barrel 1X, the moment may not be successfully cancelled, which causes the deformation of the lens.

[0085] For example, when a 1X flatness error of a lens or a lens barrel is large as a manufacturing error, the radial position where pressure is applied changes, and the deformation direction and deformation amount of the lens change.

[0086] In addition to manufacturing errors, changes in the amount of deformation caused by the pressing force are also factors that hinder the proper offset of the moment. Although the pressing force is managed by the torque, the pressing force fluctuates due to the deviation of the tightening torque and the error in the relationship between the pressing force and the torque. The amount of deformation is proportional to the pressing force, which means that as the deviation of the pressing force is large, the change in the amount of deformation increases.

[0087] When the lens unit 100X is mounted on an imaging device having an imaging element, the relative position of the imaging element and the lens unit 100X can be adjusted to correct the performance variation of the lens unit 100X. However, if the lens is deformed due to the above reasons, the lens cannot be properly corrected and the performance of the lens unit 100X varies.

[0088] Lens deformation caused by ambient temperature changes

[0089] When the ambient temperature around the lens unit 100X changes, each member in the lens unit 1X including the lens unit 100X expands or contracts according to its linear thermal expansion coefficient.

[0090] The pressure applied to each member varies with the difference in the amount of expansion or contraction between the members.

[0091] The amount of deflection of the lens is proportional to the pressing force. This means that, as the deformation state of the lens when assembling the lens unit 100X deviates, the amount of deflection of the lens changes with the ambient temperature around the lens unit 100X. In the state of the lens when assembled, the greater the deflection of the lens unit 100X, the greater its deformation. In addition, the smaller the deflection of the lens unit 100X, the smaller its deformation. As a result, the variation in deformation between multiple lens units 100X increases according to the variation in deformation during assembly.

[0092] In addition, any expansion difference between the lens and the components in contact with the lens will generate shear force due to friction in the radial direction. The local occurrence of such shear force leads to an imbalance of moment, which causes the lens to bend. Therefore, even if the deformation amount is small when assembling the lens unit 100X, the lens will be greatly deformed due to changes in ambient temperature, which will affect the performance of the lens unit 100X.

[0093] Time-dependent variation of lens deformation

[0094] Since the resin lens has viscoelasticity, it is preferred to consider the effects of stress relaxation and creep deformation. Stress relaxation refers to the phenomenon that stress is relaxed over time under a state of applied stress. Through this stress relaxation, the pressing force applied to the lens unit 100X can be relaxed. Since the deflection of the lens is roughly proportional to the pressing force, the deformation of the resin lens sometimes changes over time depending on the deformation state of the resin lens when assembling the lens unit 100X.

[0095] Creep deformation is a phenomenon in which deformation changes when a constant force is applied. Since the stress distribution inside the resin lens changes according to the shape of the resin lens when the lens unit 100X is assembled, the deformation amount of the resin lens may change over time due to creep deformation.

[0096] In addition to the above-mentioned deformation, in a lens unit including a resin lens, the axial offset of the lens may increase. In a lens unit including a resin lens, the difference in linear expansion coefficient between the lens barrel and the resin lens is greater than the difference in linear expansion coefficient between the glass lens and the lens barrel. In order to prevent the resin lens from becoming pressed into a state caused by the expansion of the resin lens in the radial direction when the ambient temperature around the lens unit changes, it is preferred to increase the gap in the radial direction. Therefore, during assembly, the lens will produce an axial offset corresponding to the gap relative to the lens barrel. In addition, due to changes in the ambient temperature around the lens unit or changes over time in the lens unit, the components housed in the lens barrel may move in the gap sometimes. This movement may cause the axial offset of the lens in the radial direction to become larger relative to when assembled.

[0097] Effects of the lens unit 100 of the first embodiment

[0098] The lens unit 100 of the present embodiment includes a resin lens 2, a glass lens 5 (a plurality of lenses), a fitting receiving portion B, a lens barrel 1, and a pressing member 6 (pressing member). The lens barrel 1 accommodates the resin lens 2 and the glass lens 5. The pressing member 6 presses the resin lens 2 and the glass lens 5 accommodated in the lens barrel 1. In addition, a fitting portion A is formed on the lens 2 to fit with the fitting receiving portion B. The fitting portion A and the fitting receiving portion B each have a conical shape having different diameters of a circle around the optical axis C along the optical axis C. That is, the fitting portion A and the fitting receiving portion B respectively have a conical shape in a cross-sectional shape in the optical axis direction, a circular shape with the optical axis C as the center in a plane orthogonal to the optical axis C, and the diameters of the above circles are different in the fitting portion A and the fitting receiving portion B according to different positions along the optical axis direction.

[0099] The resin lens 2 housed in the lens barrel 1 and positioned by fitting the fitting portion A into the fitting receiving portion B is pressed and deformed by the pressing member 6 when the lens unit 100 is assembled. The deformation of the resin lens 2 fills the gap between the fitting portion A and the fitting receiving portion B, so that the fitting portion A and the fitting receiving portion B contact each other. Thus, further deformation of the resin lens 2 can be suppressed, and the performance change of the lens unit 100 caused by the deformation can be suppressed. In addition, even if the pressing force of the pressing member 6 changes, the deformation amount of the resin lens 2 can be suppressed from increasing, and the performance change of the lens unit 100 caused by the change of the pressing force can be suppressed.

[0100] Even with changes in pressing force due to temperature changes, sensitivity to deformation due to pressing force can be reduced by balancing the moment when assembling the lens unit 100. This can reduce variations in the amount of change in the resin lens between the plurality of lens units 100.

[0101] As the ambient temperature around the lens unit 100 changes, the difference in expansion between the components of the lens unit 100 may cause friction at the contact portion between the components. In either case, a balance between the resistance N and the moment can be achieved, and the shape change of the resin lens 2 can be suppressed. Therefore, in the lens design, the deformation amount of the resin lens 2 predicted by the structural analysis when designing the lens unit 100 can be used to design the lens in consideration of the deformation amount of the resin lens 2.

[0102] The deformation of the resin lens 2 of the lens unit 100 is less sensitive to changes in the pressing force. Therefore, even if creep deformation caused by changes in the pressing force and stress relaxation occurs over time after the lens unit 100 is assembled, the change in the amount of deformation of the resin lens 2 can be reduced. With respect to creep deformation, since the deviation in the shape change of the resin lens 2 during assembly is small among the plurality of lens units 100, the change in the amount of deformation of the resin lens 2 caused by creep deformation is reduced.

[0103] In the lens unit 100, during assembly, the fitting receiving portion B of the lens barrel 1 is brought into contact with the fitting portion A of the resin lens 2, and a force is applied in the radial direction to the contact portion. Thus, the radial movement of the resin lens 2 is restricted. By bringing the fitting receiving portion B into contact with the fitting portion A, the radial movement amount of the first resin lens is reduced regardless of temperature changes or changes over time. Thus, the lens unit 100 with less axial deviation and less eccentricity of the resin lens 2 can be realized.

[0104] The embodiments of the present disclosure realize a lens unit which reduces or prevents a change in its state from a state at the time of assembly.

[0105] The plurality of lenses is not limited to two lenses, and may be three or more lenses. The number of resin lenses is not limited to one, and may be two or more. In addition, the tapered shape of the fitting portion A and the fitting receiving portion B is not limited to a shape that expands in diameter in the -Z direction, and may be a shape that expands in diameter in the +Z direction.

[0106] In the present embodiment, the resin lens 2 has a lens portion 21 and a flange portion 22 formed on the outer side of the lens portion 21. The flange portion 22 has a fitting portion A. Thus, the flange portion 22 can be actively deformed relative to the deformation of the resin lens 2, and the deformation of the lens portion 21 can be suppressed. According to the structure of the present embodiment, a lens unit 100 capable of suppressing performance changes can be provided. However, the present disclosure is not limited to such a configuration.

[0107] In this embodiment, the resin lens 2 has an annular first portion 221 that abuts against the lens barrel 1 (first component), and an annular second portion 222 that abuts against the spacer ring 4 (second component) and is on the opposite side of the first portion 221 in the direction along the optical axis C. In the resin lens 2, the second portion 222 is located between the fitting portion A and the first portion 221 in the direction orthogonal to the optical axis C. Thus, the resistance N and the pressing force F can be applied to the resin lens 2 at different positions in the radial direction, so the moment applied to the resin lens 2 can be reduced.

[0108] Second embodiment

[0109] Reference Figure 1 and Figure 2 , the structure of the lens unit of the second embodiment is described. In addition, the same reference numerals are given to the same structural elements as those of the first embodiment, and repeated descriptions are appropriately omitted. This is also the case in the other embodiments described below.

[0110] Figure 4 1 is a longitudinal sectional view showing the structure of a lens unit 100 a according to the second embodiment. Figure 5 From the -Z direction Figure 4 1 is a plan view of a second resin lens 30 included in the lens unit 100a.

[0111] like Figure 4 As shown, the lens unit 100a includes a second resin lens 30 and a light shielding portion 40. The first resin lens 2a, the second resin lens 30, and the glass lens 5 correspond to a plurality of lenses arranged along the optical axis C.

[0112] At least a portion of the outer periphery of the first resin lens 2a is formed in a substantially cylindrical shape. The outer diameter of the substantially cylindrical shape of the first resin lens 2a is smaller than the inner diameter of the lens barrel 1. Thus, the first resin lens 2a is accommodated in the lens barrel 1 with a gap therebetween.

[0113] The first resin lens 2a has a lens portion 21a and a flange portion 22a. The lens portion 21a has an optical axis C at its center, and functions as a lens for light incident on the first resin lens 2a.

[0114] The flange portion 22a is located outside the lens portion 21a. The flange portion 22a does not function as a lens for light incident on the first resin lens 2a. The flange portion 22a includes a fitting receiving portion E.

[0115] The fitting receiving portion E has a tapered shape whose diameter around the optical axis C varies depending on the position along the optical axis C. In the present embodiment, the fitting receiving portion E has a substantially conical shape in which the diameter of a circle around the optical axis C increases toward the -Z direction.

[0116] At least a portion of the outer periphery of the second resin lens 30 is formed in a substantially cylindrical shape. The outer diameter of the substantially cylindrical shape of the second resin lens 30 is smaller than the inner diameter of the lens barrel 1. Thus, the second resin lens 30 is accommodated in the lens barrel 1 with a gap therebetween.

[0117] The second resin lens 30 has a lens portion 31 and a flange portion 32. The lens portion 31 has an optical axis C at the center thereof, and functions as a lens for light incident on the second resin lens 30.

[0118] The flange portion 32 is located outside the lens portion 31. The flange portion 32 does not function as a lens for light incident on the second resin lens 30. The flange portion 32 includes a fitting portion D, a first portion 321, and a second portion 322.

[0119] The fitting portion D can be fitted into the fitting receiving portion E. The diameter of the tapered shape of the fitting portion D is slightly smaller than the diameter of the tapered shape of the fitting receiving portion E as a whole. The fitting portion D is formed on the surface on the +Z side of the flange portion 32. In the present embodiment, the fitting portion D has a substantially conical shape in which the diameter of a circle centered on the optical axis C increases toward the -Z direction.

[0120] The first portion 321 is annular and contacts the first resin lens 2a. The first resin lens 2a is an example of a first component. The first portion 321 is a side surface of the flange portion 32, formed toward the +Z direction, and substantially orthogonal to the optical axis C. The first portion 321 contacts the annular region of the surface of the first resin lens 2a substantially orthogonal to the optical axis C.

[0121] The second portion 322 is annular and abuts against the spacer ring 4 on the opposite side of the first portion 321 on the optical axis C. The second portion 322 is another side surface of the flange portion 32, formed toward the -Z direction, and substantially orthogonal to the optical axis C. The spacer ring 4 has a surface substantially orthogonal to the optical axis C, and the surface abuts against the second portion 322 in an annular region via the light shielding portion 40.

[0122] like Figure 5 As shown in FIG. 1 , in the second resin lens 30, the second portion 322 is located between the fitting portion D and the first portion 321 in a direction orthogonal to the optical axis C. In other words, the positional relationship among the fitting portion D, the first portion 321, and the second portion 322 is as follows: the fitting portion D, the second portion 322, and the first portion 321 in the order of leaving the optical axis C.

[0123] like Figure 4 As shown, the light shielding portion 40 shields the interfering light and the undesired reflected light incident on the lens unit 100a. For example, the light shielding portion 40 is a sheet-like component with a thickness of about tens of μm. The material of the light shielding portion 40 is not limited to any specific material, and resin or metal can be used. In addition, the light shielding portion 40 may not be used.

[0124] In the lens unit 100 of the first embodiment described above, the metal interlocking receiving portion B is interlocked with the resin interlocking portion A. In contrast, in the present embodiment, the interlocking receiving portion E and the interlocking portion D are both formed of resin. In this structure, when the ambient temperature around the lens unit 100a changes, the expansion difference between the interlocking portion D and the interlocking receiving portion E becomes smaller. Thus, the contact state between the interlocking portion D and the interlocking receiving portion E can be maintained with a smaller pressing force. In addition, since the shear force caused by the expansion difference at the contact point between the interlocking portion D and the interlocking receiving portion E is also small, the amount of deformation of each of the first resin lens 2a and the second resin lens 30 due to changes in the ambient temperature can be reduced.

[0125] Effects other than the above are the same as those of the first embodiment.

[0126] Third embodiment

[0127] Reference Figure 6 and Figure 7 , the structure of the lens unit of the third embodiment is described. Figure 6 1 is a longitudinal sectional view showing the structure of a lens unit 100 b according to the third embodiment. Figure 7 From the -Z direction Figure 6 FIG. 1 is a plan view of a resin lens 2b included in a lens unit 100b.

[0128] like Figure 6 As shown, the lens unit 100b has a lens barrel 1b and a resin lens 2b.

[0129] The lens barrel 1 b has a fitting receiving portion Bb and accommodates the resin lens 2 b and the glass lens 5 .

[0130] The material of the lens barrel 1b is metal such as aluminum, etc. However, the material of the lens barrel 1b may be resin or the like.

[0131] In this embodiment, the lens barrel 1b is formed in a hollow substantially cylindrical shape, and houses therein a resin lens 2b, a light shielding portion 3, a spacer ring 4, and a glass lens 5 in order. The lens barrel 1b includes a small diameter portion 11b and a contact surface 12b.

[0132] The small diameter portion 11b is annularly provided on a part of the inner side of the lens barrel 1. The inner diameter of the small diameter portion 11b is smaller than the outer diameters of the resin lens 2b and the glass lens 5 housed in the lens barrel 1. The small diameter portion 11b has a fitting receiving portion Bb.

[0133] The fitting receiving portion Bb has a tapered shape whose diameter around the optical axis C varies depending on the position along the direction of the optical axis C. In the present embodiment, the fitting receiving portion Bb has a substantially conical shape in which the diameter of a circle around the optical axis C increases toward the +Z direction.

[0134] The contact surface 12b of the small diameter portion 11b is a surface substantially perpendicular to the optical axis C of the lens unit 100b. The resin lens 2b housed in the lens barrel 1b is in contact with the contact surface 12b.

[0135] At least a portion of the outer periphery of the resin lens 2b is formed in a substantially cylindrical shape. The outer diameter of the substantially cylindrical shape of the resin lens 2b is smaller than the inner diameter of the lens barrel 1b. Thus, the first resin lens 2b is accommodated in the lens barrel 1b with a gap therebetween.

[0136] The first resin lens 2b has a lens portion 21b and a flange portion 22b. The lens portion 21b has an optical axis C at its center, and functions as a lens for light incident on the first resin lens 2b.

[0137] The flange portion 22b is located outside the lens portion 21b. The flange portion 22b does not function as a lens for light incident on the resin lens 2b. The flange portion 22b includes a fitting portion Ab, a first portion 221b, and a second portion 222b.

[0138] The fitting portion Ab can be fitted into the fitting receiving portion Bb. The diameter of the tapered shape of the fitting portion Ab is slightly smaller than the overall diameter of the tapered shape of the fitting receiving portion Bb. The fitting portion Ab is formed on the surface on the +Z side of the flange portion 22b. In the present embodiment, the fitting portion Ab has a substantially conical shape in which the diameter of a circle centered on the optical axis C varies depending on the position along the direction of the optical axis C.

[0139] The first portion 221b is annular and contacts the lens barrel 1b. The lens barrel 1b is an example of a first member. The first portion 221b is a surface of the flange portion 22b that faces the +Z direction and is substantially perpendicular to the optical axis C. The first portion 221b contacts the surface of the small diameter portion 11 of the lens barrel 1b that is substantially perpendicular to the optical axis C in an annular region.

[0140] The second portion 222b is annular and contacts the spacer ring 4 on the opposite side of the first portion 221b in the direction of the optical axis C. The second portion 222b is a surface of the flange portion 22b that is formed toward the -Z direction and is substantially orthogonal to the optical axis C. The spacer ring 4 has a surface substantially orthogonal to the optical axis C, which contacts the annular region via the light shielding portion 3 relative to the second portion 222b.

[0141] like Figure 7 As shown, in the resin lens 2b, the second portion 222b is located between the fitting portion Ab and the first portion 221 in a direction orthogonal to the optical axis C. In other words, the positional relationship among the fitting portion Ab, the first portion 221b, and the second portion 222b is: in order of approaching the optical axis C, the first portion 221b, the second portion 222b, and the fitting portion Ab.

[0142] The positional relationship between the interlocking portion D, the first portion 321 and the second portion 322 is as follows: in the order of leaving from the optical axis C, they become the interlocking portion D, the second portion 322 and the first portion 321.

[0143] The moment M1b and the moment M2a represent the moments applied to the resin lens 2b. Figure 1 The moment M1 in is opposite, that is, it points in the +Z direction. The moment M2a is Figure 1 The moment M2 in is opposite, that is, it points in the +Z direction.

[0144] The lens unit 100 b exerts the same effects as the lens unit 100 of the first embodiment.

[0145] The following are aspects of the present disclosure that are intended to achieve the desired performance:

[0146] Aspect 1

[0147] A lens unit includes: a plurality of lenses arranged along the optical axis of the lens unit, the plurality of lenses including at least one resin lens; a lens barrel for storing the plurality of lenses, the lens barrel including a fitting receiving portion; and a pressing member configured to press the plurality of lenses stored in the lens barrel. The at least one resin lens includes a fitting portion that can be fitted into the fitting receiving portion. The fitting portion and the fitting receiving portion each have: a conical cross-sectional shape along the optical axis; and a circular shape centered on the optical axis in a plane orthogonal to the optical axis. The diameter of the circle varies depending on the position on the optical axis.

[0148] Aspect 2

[0149] In the lens unit according to aspect 1, the at least one resin lens further comprises: a lens portion; and a flange portion located outside the lens portion in a radial direction from the optical axis in the plane. The flange portion includes the fitting portion.

[0150] Aspect Three

[0151] In the lens unit according to aspect one or aspect two, the lens barrel includes a first member. The lens unit further includes a second member housed in the first member. The at least one resin lens further includes: a first portion having an annular shape, the first portion contacts the first member at one end of the optical axis of the at least one resin lens; and a second portion having an annular shape, the second portion contacts the second member at the other end of the optical axis of the at least one resin lens. The second portion is radially located between the fitting portion and the first portion.

[0152] Aspect 4

[0153] In the lens unit according to the first aspect, the fitting receiving portion has a conical shape whose diameter increases toward the pressing member on the optical axis.

[0154] Aspect 5

[0155] A lens unit includes: a plurality of lenses arranged along the optical axis of the lens unit, the plurality of lenses including at least two resin lenses; a lens barrel to accommodate the plurality of lenses; and a pressing member configured to press the plurality of lenses accommodated in the lens barrel. The at least two resin lenses include: a first resin lens; and a second resin lens adjacent to the first resin lens. The first resin lens includes a fitting receiving portion. The second resin lens includes a fitting portion that can be fitted into the fitting receiving portion. The fitting portion and the fitting receiving portion each have: a conical cross-sectional shape along the optical axis; and a circular shape centered on the optical axis in a plane orthogonal to the optical axis. The diameter of the circle varies depending on the position on the optical axis.

[0156] Aspect 6

[0157] In the lens unit according to aspect 5, the first resin lens includes: a first lens portion; and a first flange portion, located outside the first lens portion in the radial direction from the optical axis in the plane, the first flange portion including the fitting receiving portion. The second resin lens further includes: a second lens portion; and a second flange portion, located outside the second lens portion in the radial direction, the second flange portion including the fitting portion.

[0158] Aspect 7

[0159] In the lens unit according to aspect 5 or aspect 6, the first resin lens is a first member. The lens unit further includes a second member housed in the lens barrel. The second resin lens further includes: a first portion having an annular shape at one end of the second resin lens along the optical axis and contacting the first member; and a second portion having an annular shape at the other end opposite to the first portion along the optical axis and contacting the second member. The second portion is located between the fitting portion and the first portion in a direction orthogonal to the optical axis.

[0160] Aspect 8

[0161] In the lens unit according to aspect 5, the fitting receiving portion has a conical shape whose diameter increases toward the pressing member on the optical axis.

[0162] The above embodiments are illustrative and do not limit the present invention. Therefore, many additional modifications and variations are possible based on the above teachings. For example, within the scope of the present invention, the elements and / or characteristics of different illustrative embodiments can be combined and / or replaced with each other.

[0163] This patent application is based upon and claims the benefit of priority from Japanese patent application No. 2022-080957 filed with the Japan Patent Office on May 17, 2022, the disclosure of which is incorporated herein in its entirety by reference.

[0164] Reference numerals list

[0165] 1. 1b tube

[0166] 11, 11b small diameter section

[0167] 12, 12b contact surface

[0168] 2.2b resin lens

[0169] 2a The first resin lens

[0170] 21, 21a, 21b lens portion

[0171] 22, 22a, 22b flange portion

[0172] 221, 221b Part 1

[0173] 222, 222b Part 2

[0174] 3. 40 shading part

[0175] 4 Spacer Rings

[0176] 5. Glass lens

[0177] 6 Pressing member

[0178] 30 Second resin lens

[0179] 31 Lens Department

[0180] 32 flange

[0181] 321 Part 1

[0182] 322 Part 2

[0183] 100, 100a, 100b lens unit

[0184] A, Ab, D chimeric part

[0185] B, Bb, E chimeric acceptor

[0186] C optical axis

[0187] F Pressing force

[0188] M1, M2, M1b, M2b torque

[0189] N resistance

Claims

1. A lens unit, comprising: A plurality of lenses are arranged along the optical axis of the lens unit, wherein the plurality of lenses include at least one resin lens; A lens barrel for accommodating the plurality of lenses, wherein the lens barrel comprises a fitting receiving portion; as well as A pressing member is configured to press the plurality of lenses housed in the lens barrel, wherein the at least one resin lens includes a fitting portion that can be fitted into the fitting receiving portion, The fitting portion and the fitting receiving portion each have: a tapered cross-sectional shape along the optical axis; and The shape of a circle centered on the optical axis in a plane orthogonal to the optical axis, The diameter of the circle varies depending on the position on the optical axis.

2. The lens unit according to claim 1, in, The at least one resin lens further comprises: a lens portion; and a flange portion located outside the lens portion in a radial direction from the optical axis in the plane, The flange portion includes the fitting portion.

3. The lens unit according to claim 1 or 2, in, The lens barrel comprises a first member, The lens unit further includes a second member received in the first member, The at least one resin lens further comprises: a first portion having a ring shape, the first portion contacting the first member at one end of the optical axis of the at least one resin lens; as well as a second portion having a ring shape, the second portion contacting the second member at the other end of the optical axis of the at least one resin lens, The second portion is located between the fitting portion and the first portion in a radial direction.

4. The lens unit according to claim 1, in, The fitting receiving portion has a conical shape whose diameter increases toward the pressing member on the optical axis.

5. A lens unit, comprising: A plurality of lenses are arranged along the optical axis of the lens unit, wherein the plurality of lenses include at least two resin lenses; A lens barrel for storing the plurality of lenses; as well as A pressing member is configured to press the plurality of lenses housed in the lens barrel, Wherein, the at least two resin lenses include: a first resin lens; and a second resin lens adjacent to the first resin lens, The first resin lens includes a fitting receiving portion, The second resin lens includes a fitting portion that can be fitted into the fitting receiving portion. The fitting portion and the fitting receiving portion each have: a tapered cross-sectional shape along the optical axis; and The shape of a circle centered on the optical axis in a plane orthogonal to the optical axis, The diameter of the circle varies depending on the position on the optical axis.

6. The lens unit according to claim 5, in, The first resin lens comprises: a first lens portion; and a first flange portion located outside the first lens portion in a radial direction from the optical axis in the plane, the first flange portion including the fitting receiving portion, and The second resin lens further comprises: a second lens portion; and The second flange portion is located outside the second lens portion in the radial direction, and the second flange portion includes the fitting portion.

7. The lens unit according to claim 5 or 6, in, The first resin lens is a first member, The lens unit further includes a second member received in the lens barrel, The second resin lens further comprises: a first portion having a ring shape at one end of the second resin lens along the optical axis and contacting the first member; as well as a second portion having a ring shape at the other end opposite to the first portion along the optical axis and contacting the second member, The second portion is located between the fitting portion and the first portion in a direction orthogonal to the optical axis.

8. The lens unit according to claim 5, in, The fitting receiving portion has a conical shape whose diameter increases toward the pressing member on the optical axis.

Images