Lens unit and image pickup apparatus

Abstract

The invention provides a lens unit and an image pickup apparatus. The lens unit includes: a holding member that holds a lens on an inner peripheral side; and a pressing member disposed on an inner periphery of the holding member, contacting a contact surface of the holding member from the optical axis direction, fixed to the holding member by a fixing member, and thereby pressing the lens against the holding member from the optical axis direction. The holding member has a first recess that is recessed toward the outside in the radial direction at at least one position in the circumferential direction. The pressing member has a second recess that is recessed toward the inside in the radial direction at at least one position in the circumferential direction. The fixing member is disposed in a region facing the first recess, the second recess, and the contact surface.

Description

Technical Field

[0001] The present disclosure relates to an imaging device such as a vehicle-mounted camera and a surveillance camera. Background Art

[0002] As mentioned above, the camera equipment commonly used in outdoor environments is required to have resistance to external impact.

[0003] Japanese Patent Publication No. 2020-27284 discloses a lens module, which includes a first lens arranged on the subject side and a fixing member for holding the first lens by pressing the first lens against the front end of the lens barrel from the subject side. The lens barrel is bonded and fixed to the fixing member. Japanese Patent Publication No. 2020-27278 discloses a lens module, which includes a lens arranged on the subject side and a fixing member for pressing the lens against the front end of the lens barrel from the subject side to fix the lens. An adhesive is filled between the contact portion of the lens and the contact lens of the fixing member.

[0004] In order to improve the impact resistance, it is effective to bond the lens to the fixing member. However, the structure of Japanese Patent Publication No. 2020-27284 is based on the premise that the fixing member is fixed to the outer periphery of the lens barrel, and the size of the lens module increases due to the radial size of the fixing member. In the structure of Japanese Patent Publication No. 2020-27278, since an adhesive is applied between the fixing member and the lens, it is necessary to assemble the lens in a manner that the adhesive does not diffuse into the optically effective area of ​​the lens, and assembly is not easy. Summary of the invention

[0005] According to one aspect of the present disclosure, a lens unit includes: a holding member that holds a lens on the inner circumference side; and a pressing member that is arranged on the inner circumference of the holding member, contacts a contact surface of the holding member from the optical axis direction, is fixed to the holding member by a fixing member, and thereby presses the lens against the holding member from the optical axis direction. The holding member has a first recess that is concave toward the radial outer side at at least one position in the circumferential direction. The pressing member has a second recess that is concave toward the radial inner side at at least one position in the circumferential direction. The fixing member is arranged in an area facing the first recess, the second recess, and the contact surface. An imaging device having the above lens unit also constitutes another aspect of the present disclosure.

[0006] Further features of the present disclosure will become apparent from the following description of exemplary embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1A , Figure 1B and Figure 1C 3 and 4 are respectively a rear view and a cross-sectional view of the lens unit according to Embodiment 1.

[0008] Figure 2 is a cross-sectional view of an imaging unit according to Embodiment 1.

[0009] Figure 3 is an exploded perspective view of the imaging unit according to Embodiment 1 as viewed from the subject side.

[0010] Figure 4 is an exploded perspective view of the imaging unit according to Embodiment 1 viewed from the image side.

[0011] Figure 5 is a perspective view of a camera according to Example 1.

[0012] Fig. 6A , Figure 6B and Figure 6C are a rear view and a cross-sectional view of a lens unit according to Embodiment 2.

[0013] Figure 7 is a cross-sectional view of an imaging unit according to Embodiment 2. DETAILED DESCRIPTION

[0014] Embodiments according to the present disclosure will now be described with reference to the accompanying drawings.

[0015] Example 1

[0016] The imaging apparatus according to Embodiment 1 is particularly suitable for use in vehicle-mounted (in-vehicle) cameras and surveillance cameras used in outdoor environments. However, the imaging apparatus according to the embodiments of the present disclosure also includes apparatuses used indoors.

[0017] Figure 5 The external appearance of the camera 100 according to the present embodiment is illustrated. The camera 100 includes an imaging unit 1 as an image pickup device and an exterior member 2 that holds the imaging unit 1. A portion of the imaging surface side of the imaging unit 1 is housed in the exterior member 2 and fixed to the exterior member 2 with screws not shown, and a portion of the subject side of the imaging unit 1 is exposed from an opening provided in the front of the exterior member 2. A gap between the opening of the exterior member 2 and the outer periphery of the imaging unit 1 is sealed with a sealing member not shown, thereby preventing water and dust from entering through the gap.

[0018] The cover 3 is fixed to the back of the outer member 2 with screws not shown. The outer member 2 and the cover 3 sandwich a sealing member not shown, thereby preventing water and dust from entering through the gap between the outer member 2 and the cover 3. In addition, the cover 3 is provided with an external interface not shown. By connecting a cable to the external interface, a video signal generated by imaging using the imaging unit 1 can be output to the outside. The external interface may have a wireless communication function for the video signal.

[0019] Figure 2The internal structure of the imaging unit 1 is illustrated. Figure 3 An exploded view of the imaging unit 1 viewed from the subject side is illustrated. Figure 4 An exploded view of the imaging unit 1 viewed from an image plane side (hereinafter referred to as a sensor side) is illustrated. Figure 2 The dot-dash line in represents the optical axis. In the following description, the direction in which the optical axis extends will be referred to as the optical axis direction, the direction perpendicular to the optical axis will be referred to as the radial direction, and the direction around the optical axis will be referred to as the circumferential direction.

[0020] The housing 4 has an opening 4a on the subject side, an opening 4b on the sensor side, and an inner peripheral threaded portion 4c provided on the inner peripheral portion, and holds the lens unit 30 on the inner peripheral side thereof. The lens unit 30 includes a lens frame 5 and lenses 6a, 6b, 6c, 6d. The lens unit 30 is inserted into the opening 4a and is held by the housing 4 by screwing the outer peripheral threaded portion 5a provided on the outer peripheral portion of the lens frame 5 into the inner peripheral threaded portion 4c provided on the inner peripheral portion of the housing 4.

[0021] For weather resistance when used outdoors, the housing 4 and the lens frame 5 may be made of metal. A peripheral groove portion 5b is formed in the outer peripheral portion of the lens frame 5 on the subject side of the outer peripheral threaded portion 5a, and an elastic body (second sealing member) 7 such as an O-ring is fitted into the peripheral groove portion 5b. The elastic body 7 seals the gap between the outer peripheral portion of the lens frame 5 and the inner peripheral portion of the housing 4 to prevent water and dust from entering through the gap therebetween.

[0022] The sensor unit 8 includes an image sensor 8a such as a CMOS sensor. The sensor unit 8 is placed inside the opening 4b of the housing 4, and is fixed to a receiver provided in the opening 4b with a screw 9. Thus, the sensor unit 8 and the lens unit 30 are held together by the housing 4. As described above, the outer peripheral threaded portion 5a of the lens unit 30 is screwed to the inner peripheral threaded portion 4c of the housing 4, and the position of the lens unit 30 relative to the sensor unit 8 in the optical axis direction can be adjusted by rotating the lens unit 30 relative to the housing 4 around the optical axis.

[0023] In the lens unit 30, the lens frame 5 as a holding member (holder) holds the lenses 6a to 6d on its inner peripheral side. Openings are formed at both the end on the subject side and the end on the sensor side of the lens frame 5. The lens 6b, the spacer 11, the elastomer 10 such as an O-ring, and the lens 6a are sequentially inserted into the inner peripheral portion of the lens frame 5 from the opening on the subject side. The front pressure ring 12 is fixed to the lens frame 5 and contacts the lens 6a arranged closest to the subject by screwing the unillustrated outer peripheral threaded portion on the outer peripheral portion of the front pressure ring 12 into the unillustrated inner peripheral threaded portion on the inner peripheral portion of the lens frame 5. Therefore, the elastomer 10 is clamped between the lens 6a and the lens frame 5, and the gap between the lens 6a and the lens frame 5 is sealed to prevent water and dust from entering through the gap.

[0024] The lens 6c is inserted into the inner periphery of the lens frame 5 from the opening on the sensor side, and is fixed to the lens frame 5 by an adhesive as a fixing member. The lens 6d, the fixing plate 13, and an elastic body (elastic member) 14 such as an O-ring are sequentially inserted into the inner periphery of the lens frame 5 from the opening on the sensor side. The rear pressure ring 15 as a pressure member is fixed to the lens frame 5, and contacts the elastic body 14 by screwing an outer peripheral threaded portion 15a provided on the outer periphery of the rear pressure ring 15 into an inner peripheral threaded portion 5c provided on the inner periphery of the lens frame 5.

[0025] The rear pressure ring 15 is screwed into the lens frame 5 until its contact surface 15b contacts the contact surface 5e of the lens frame 5. Therefore, the elastomer 14 is clamped between the rear pressure ring 15 and the fixing plate 13, and the rear pressure ring 15 is held by the lens frame 5 in a state where the lens 6d closest to the image sensor is urged toward the subject side by the elastic force of the elastomer 14. In this structure, the lens 6d is pressed against the lens frame 5 with a force smaller than the force in the case where the rear pressure ring 15 directly presses the lens 6d toward the subject side. This structure can suppress the deformation of the lens surface of the lens 6d and prevent the degradation of the optical performance. As long as the deformation of the lens surface of the lens 6d is suppressed, the lens 6d can be held by the lens frame 5, and the rear pressure ring 15 can directly contact the lens 6d.

[0026] Figure 1A The lens unit 30 is shown as viewed from the sensor side. Figure 1B Picture shows Figure 1A AA section in. Figure 1C Picture shows Figure 1B Magnified view of area B in FIG.

[0027] A notch portion 5d is formed at a circumferential position of the inner circumferential threaded portion 5c of the lens frame 5 as a first recessed portion that is recessed outward in the radial direction. The circumferential surface within the notch portion 5d is an arc surface (a portion of a cylindrical surface) extending in the direction of the optical axis. On the other hand, a notch portion 15c is formed at a circumferential position of the outer circumferential threaded portion 15a of the rear pressure ring 15 as a second recessed portion that is recessed inward in the radial direction. A portion of the circumferential surface of the notch portion 15c on the subject side is an arc surface extending in the direction of the optical axis, and a portion thereof on the sensor side is an inclined surface (a frustum of a cone) that is inclined relative to the optical axis direction so as to be closer to the optical axis at a position close to the image sensor.

[0028] In a state where the rear pressure ring 15 is assembled to the lens frame 5 by screwing, the notch portions 15c and 5d face each other in the radial direction, that is, they are positioned in the same phase in the circumferential direction. The contact surface 5e is exposed toward the sensor side between the notch portions 15c and 5d. As a result, a space (area) V1 is formed that faces the notch portion 15c, the notch portion 5d, and the contact surface 5e and opens toward the sensor side. The adhesive AD is placed in this space V1. Therefore, the rear pressure ring 15 (notch portion 15c) is bonded and fixed to the lens frame 5 (notch portion 5d and contact surface 5e).

[0029] By providing the notch 15c with an inclined surface, the radial width of the opening of the space V1 on the sensor side is increased, and the workability of filling the adhesive in the space V1 is improved. At least one of the notches 15c and 5d may be formed so that the radial width of the space V1 increases toward the sensor side (the side opposite to the contact surface 5e in the optical axis direction).

[0030] This embodiment uses fixation using an adhesive, but the space V1 may be fixed by filling the space V1 with an elastic body such as a sealant without using an adhesive.

[0031] The circumferential length of the notch portion of either the notch portion 5d or the notch portion 15c may be longer than the circumferential length of the other. Therefore, even if the phases of the notches 5d and 15c are slightly offset due to manufacturing variations of the components, the circumferential lengths of the notches 15c and 5d facing each other to form the space V1 can be sufficiently ensured, and good bonding strength can be obtained. The notches 15c and 5d may be provided at a plurality of positions on the circumference of the rear pressure ring 15 and the lens frame 5, respectively.

[0032] Thus, the present embodiment screws the rear pressure ring 15 into the lens frame 5, miniaturizes the lens unit 30, and forms an adhesive reservoir (space V1) for fixing the rear pressure ring 15 to the lens frame 5 using an adhesive. Therefore, the adhesive AD for bonding the rear pressure ring 15 can be bonded to the lens frame 5 without moving to the lens surface of the lens 6d. In other words, the lens unit can be provided with good assembly performance (bonding workability) and the enlargement of the lens unit 30 in the radial direction can be suppressed.

[0033] In the present embodiment, the holding structure of the rear pressure ring 15 holds the lens 6d closest to the image sensor, but the same holding structure can also be applied to the front pressure ring 12 that holds the lens 6a closest to the subject.

[0034] Example 2

[0035] Embodiment 2 will now be described. Figure 7 The internal structure of the imaging unit 1000 according to Embodiment 2 is illustrated. Those elements in this embodiment corresponding to those in Embodiment 1 will be designated by the same reference numerals, and their description will be omitted. In this embodiment, the lens unit 300 having a different structure from the lens unit 30 in Embodiment 1 will be mainly described.

[0036] The lens unit 300 includes a lens frame 50 as a first holding member that directly fixes and holds the lenses 6a to 6d, and an outer frame 16 as a second holding member that holds the lens frame 50 on the inner peripheral side. Openings are provided at the end on the subject side and the end on the sensor side of each of the lens frame 50 and the outer frame 16.

[0037] The lens frame 50 is made of resin, and the outer frame 16 may be made of metal. Since the lens frame 50 is a resin component, the lenses 6a to 6d can be pressed into the inner periphery of the lens frame 50 and held thereby. Therefore, the lenses can be held with a higher positional accuracy than that of Embodiment 1 in which the lens frame 5 is a metal component. By holding the lens frame 50 with the metal outer frame 16, the lens frame 50 can be prevented from being directly exposed to an outdoor environment such as sunlight, and the weather resistance of the lens unit 300 can be improved.

[0038] The lens unit 300 is inserted into the opening 4 a of the housing 4 , and is held by the housing 4 because the outer peripheral threaded portion 16 e provided on the outer peripheral portion of the outer frame 16 is screwed into the inner peripheral threaded portion 4 c of the housing 4 .

[0039] The lens frame 50 holds the lenses 6a to 6d at its inner periphery. The lenses 6b and 6a are sequentially inserted into the inner periphery of the lens frame 50 from the opening on the subject side. The lenses 6a and 6b are fixed and held by the lens frame 50 by thermal caulking. An elastic body (first sealing member) 70 such as an O-ring is arranged in a step portion on the subject side provided at the outer periphery of the lens 6a.

[0040] The lens 6c is inserted into the inner periphery of the lens frame 50 from the opening on the sensor side. The lens 6c is fixed and held by the lens frame 50 by heat caulking. An outer peripheral threaded portion 50a is formed on the outer periphery of the lens frame 50. The lens frame 50 is held by the outer frame 16 by screwing the outer peripheral threaded portion 50a into the inner peripheral threaded portion 16a received by the inner periphery of the outer frame 16.

[0041] At this time, the elastic body 70 is sandwiched between the flange portion 16b formed as a protrusion protruding toward the inside in the radial direction at the front end (the subject side of the lens 6a arranged closest to the subject) of the outer frame 16 and the lens 6a held by the lens frame 50. This structure seals the gap between the flange portion 16b and the lens 6a, and prevents water and dust from entering through the gap.

[0042] The lens 6d, the fixing plate 13, the elastic body 14, and the rear pressure ring 15 as a pressure member are sequentially inserted from the opening on the sensor side into the inner periphery of the outer frame 16 that holds the lens frame 50. By screwing an outer peripheral threaded portion 15a provided on the outer periphery of the rear pressure ring 15 into an inner peripheral threaded portion 16c provided on the inner periphery of the outer frame 16, the rear pressure ring 15 is held by the outer frame 16 and contacts the elastic body 14.

[0043] The rear pressure ring 15 is screwed into the outer frame 16 until its contact surface 15e contacts the contact surface 50e of the lens frame 50. Therefore, similarly to Example 1, the elastomer 14 is clamped between the rear pressure ring 15 and the fixing plate 13, and the rear pressure ring 15 is held by the outer frame 16 in a state where the lens 6d closest to the sensor is urged toward the subject side by the elastic force of the elastomer 14. In this structure, the lens 6d is pressed against the lens frame 50 with a force smaller than the force in the case where the rear pressure ring 15 is directly pressed against the lens frame 50 toward the subject side. Thus, this structure can suppress deformation of the lens surface of the lens 6d and prevent degradation of optical performance. As long as deformation of the lens surface of the lens 6d is suppressed, the lens 6d can be held by the lens frame 50 in a state where the rear pressure ring 15 directly contacts the lens 6d.

[0044] Fig. 6A The lens unit 300 is shown as viewed from the sensor side. Figure 6B The diagram shows the Fig. 6A Section taken along line CC in FIG. Figure 6CPicture shows Figure 6B Magnified view of area D in FIG.

[0045] A notch 16d is formed at one circumferential position of the inner circumferential threaded portion 16c of the outer frame 16 as a first concave portion concave outward in the radial direction. The circumferential surface in the notch 16d is an arc surface (a part of a cylindrical surface) extending in the optical axis direction. As in the first embodiment, a notch 15c is formed at one circumferential position of the outer circumferential threaded portion 15a of the rear pressure ring 15 as a second concave portion concave inward in the radial direction. A part of the circumferential surface in the notch 15c on the subject side is an arc surface extending in the optical axis direction, while a part on the sensor side is an inclined surface.

[0046] In a state where the rear pressure ring 15 is screwed to the outer frame 16, the notch portions 15c and 16d are positioned so as to face each other in the radial direction (at the same phase in the circumferential direction). The contact surface 50e of the lens frame 50 is exposed toward the sensor side between the notch portions 15c and 16d. As a result, a space (area) V2 is formed that faces the notch portion 15c, the notch portion 16d, the contact surface 50e and opens toward the sensor side. The adhesive AD is placed in this space V2. Therefore, the rear pressure ring 15 (notch portion 15c) is bonded and fixed to the outer frame 16 (notch portion 16d) and the lens frame 50 (contact surface 50e).

[0047] This embodiment provides the notch portion 15c having an inclined surface, increases the width of the sensor side opening of the space V2 in the radial direction, and improves the workability of filling the adhesive in the space V2. At least one of the notch portions 15c and 16d may be formed so that the width of the space V2 in the radial direction becomes wider toward the sensor side (the side opposite to the contact surface 50e in the optical axis direction).

[0048] Regarding the circumferential length of the notch portion, one of the notch portion 16d or the notch portion 15c can be longer than the other. Therefore, even if the phases of the notch portions 16d and 15c are slightly offset due to manufacturing variations of the components, the circumferential lengths of the notch portions 16d and 15c facing each other to form the space V2 can be fully ensured, and good bonding strength can be obtained. The notch portions 15c and 16d can be respectively arranged at multiple positions on the circumference of the rear pressure ring 15 and the outer frame 16. In this embodiment, the rear pressure ring 15 is screwed into the outer frame 16, the lens unit 300 is miniaturized, and an adhesive storage portion (space V2) for bonding the rear pressure ring 15 to the outer frame 16 and the lens frame 50 is formed. Therefore, by preventing the adhesive used to bond the rear pressure ring 15 from moving to the lens surface of the lens 6d, the adhesive can bond the rear pressure ring 15 to the outer frame 16 and the lens frame 50. In other words, it is possible to provide a lens unit having good assembling performance (adhesion workability) while suppressing enlargement of the lens unit 300 in the radial direction.

[0049] Embodiment 1 and Embodiment 2 use a holding structure in which the rear pressure ring 15 is screwed to the lens frame 5 or the outer frame 16 , but another holding structure such as a bayonet connection may be used.

[0050] Each embodiment can provide a lens unit that is easy to assemble while suppressing radial enlargement, and an image pickup apparatus including the lens unit.

[0051] While the present disclosure has been described with reference to the embodiments, it is to be understood that the present disclosure is not limited to the disclosed embodiments.The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

[0052] Each embodiment can provide a lens unit that is easy to assemble while suppressing enlargement in the radial direction, and an image pickup apparatus having the lens unit.

Claims

1. A lens unit, comprising: a holding member that holds the lens on the inner peripheral side; and a pressing member arranged at the inner periphery of the holding member, contacting a contact surface of the holding member from the optical axis direction, fixed to the holding member by a fixing member and thereby pressing the lens against the holding member from the optical axis direction, The invention is characterized in that the retaining member has a first recessed portion, and the first recessed portion is recessed toward the outside in the radial direction at at least one position in the circumferential direction. wherein the pressurizing member has a second recessed portion, the second recessed portion being recessed inward in the radial direction at at least one position in the circumferential direction, and, The fixing member is arranged in a region facing the first recess, the second recess and the contact surface.

2. The lens unit according to claim 1, characterized in that: The fixing member is an adhesive.

3. The lens unit according to claim 2, characterized in that: The retaining member has an inner peripheral threaded portion, wherein the pressurizing member has an outer peripheral threaded portion, The pressurizing member is assembled to the holding member by screwing the outer peripheral threaded portion into the inner peripheral threaded portion until the pressurizing member contacts the contact surface, and the pressurizing member is fixed to the holding member by the adhesive.

4. The lens unit according to claim 2, characterized in that: The holding member includes a first holding member that fixes the lens and a second holding member that holds the first holding member on the inner peripheral side. wherein the pressing member contacts a contact surface provided on the first holding member and is fixed to the first holding member and the second holding member by the adhesive, Wherein, the first recess is arranged on the second retaining member.

5. The lens unit according to claim 4, characterized in that: The second retaining member has an inner peripheral threaded portion, wherein the pressurizing member has an outer peripheral threaded portion, and The pressurizing member is assembled to the second holding member by screwing the outer threaded portion into the inner threaded portion until the pressurizing member contacts the contact surface, and the pressurizing member is fixed to the first holding member and the second holding member by the adhesive.

6. The lens unit according to claim 4, characterized in that: the second holding member having a protrusion that protrudes toward a radially inner portion on a subject side of a lens disposed closest to the subject among the lenses held by the first holding member, The first sealing member is arranged between the protruding portion and a lens arranged closest to the object.

7. The lens unit according to claim 3, characterized in that: The first recess is provided at at least one position in the circumferential direction of the inner peripheral threaded portion. Wherein, the second recessed portion is provided at at least one position in the circumferential direction of the outer peripheral threaded portion.

8. The lens unit according to claim 1, wherein: At least one of the first recessed portion and the second recessed portion is formed such that a width of the region in the radial direction increases toward a side opposite to the contact surface in the optical axis direction.

9. The lens unit according to claim 1, wherein: A circumferential length of at least one of the first recessed portion and the second recessed portion is longer than a length of the other of the first recessed portion and the second recessed portion.

10. The lens unit according to claim 1, wherein: An elastic member is arranged between the pressing member and the lens, The pressing member presses the lens against the holding member via the elastic member.

11. A camera device, comprising: Lens unit; and an image sensor configured to form an image of a subject through the lens unit, The lens unit comprises: a holding member that holds the lens on the inner peripheral side; and a pressing member arranged at the inner periphery of the holding member, contacting a contact surface of the holding member from the optical axis direction, fixed to the holding member by a fixing member and thereby pressing the lens against the holding member from the optical axis direction, The invention is characterized in that the retaining member has a first recessed portion, and the first recessed portion is recessed toward the outside in the radial direction at at least one position in the circumferential direction. wherein the pressurizing member has a second recessed portion, the second recessed portion being recessed inward in the radial direction at at least one position in the circumferential direction, and, The fixing member is arranged in a region facing the first recess, the second recess and the contact surface.

12. The imaging device according to claim 11, further comprising a housing that holds the lens unit and the image sensor on an inner peripheral side, It is characterized in that The lens unit is held by the housing so that a position of the lens unit can be adjusted relative to the image sensor in the optical axis direction.

13. The imaging device according to claim 12, wherein: A second sealing member is arranged between an inner peripheral portion of the housing and an outer peripheral portion of the retaining member.

Images