WO2017168959A1

WO2017168959A1 - Lens unit

Info

Publication number: WO2017168959A1
Application number: PCT/JP2017/001281
Authority: WO
Inventors: 大樹吉田; 健介益居
Original assignee: 富士フイルム株式会社
Priority date: 2016-03-29
Filing date: 2017-01-16
Publication date: 2017-10-05
Also published as: JP2019095463A

Abstract

Provided is a lens unit having: a resin lens barrel formed cylindrically and configured such that a plurality of locations in the circumferential direction thereof includes an inner wall and an outer wall that faces the inner wall in the radial direction, having a cavity interposed therebetween, and is thicker in the radial direction than the inner wall; and a lens coming in contact with the plurality of inner walls and fitting to the lens barrel.

Description

Lens unit

This disclosure relates to a lens unit.

Japanese Patent Nos. 4847020 and 5406165 disclose a lens unit in which a plurality of plastic (resin) lenses are press-fitted into a plastic (resin) lens barrel having a polygonal inner peripheral surface. ing. On the other hand, Japanese Patent Application Laid-Open No. 2006-198763 discloses a holder having a support member that can be elastically deformed as a holder for holding a component such as a lens. Japanese Patent No. 4668410 discloses a structure in which the outer peripheral portion of the lens barrel is recessed to form a thin portion, and the lens is held by this thin portion.

As in the technique disclosed in Japanese Patent No. 4847020 and Japanese Patent No. 5406165, a resin barrel may be used from the viewpoint of cost reduction and moldability. Here, when the external temperature rises, the force acting on the contact part between the lens barrel and the lens changes due to the difference in the linear expansion coefficient (thermal expansion coefficient) between the lens barrel and the lens, and the optical characteristics are maintained well. Can be difficult to do. As countermeasures, a structure using a support member that can be elastically deformed as disclosed in Japanese Patent Application Laid-Open No. 2006-198763, or a structure in which a lens is held by a thin portion as disclosed in Japanese Patent No. 4668410 is conceivable. However, these have room for improvement from the viewpoint of securing strength against external force acting on the lens barrel.

The present disclosure provides a lens unit capable of ensuring the strength of the lens barrel while maintaining good optical characteristics even when the external temperature is increased.

A first aspect of the present disclosure is a lens unit, which is formed in a cylindrical shape, and a plurality of circumferential positions are opposed to the inner wall and the inner wall in a radial direction with a hollow portion interposed therebetween and are more radial than the inner wall. And a lens barrel made of resin including a thick outer wall, and a lens fitted in the lens barrel in contact with the plurality of inner walls.

According to the lens unit according to the first aspect of the present disclosure, the plurality of circumferential positions in the lens barrel are opposed to the inner wall and the inner wall in the radial direction with the hollow portion interposed therebetween, and are thicker in the radial direction than the inner wall. It is comprised including an outer wall. As a result, the lens unit according to the first aspect suppresses a change in the force acting on the contact portion between the lens barrel and the lens by bending and deforming the inner wall of the lens barrel that is in contact with the lens during thermal expansion. it can. As a result, the lens unit according to the first aspect can suppress changes in optical characteristics even when the external temperature is increased.

Further, in the lens unit according to the first aspect, the radial thickness of the outer wall is thicker than the radial thickness of the inner wall. Thereby, in the lens unit according to the first aspect, the radial thickness of the outer wall is the same as the radial thickness of the inner wall, or the radial thickness of the outer wall is smaller than the radial thickness of the inner wall. Thus, the strength of the lens barrel can be ensured.

In the lens unit according to the second aspect of the present disclosure, in the lens unit according to the first aspect, the radial thickness of the outer wall may be larger than the radial distance between the inner wall and the outer wall.

According to the lens unit according to the second aspect of the present disclosure, the radial thickness of the outer wall is the same as the radial interval between the inner wall and the outer wall (the radial width in the cavity), or the radial direction of the outer wall. Compared with the case where the thickness of the lens is thinner than the radial width of the cavity, the strength of the lens barrel can be improved.

In the lens unit according to the third aspect of the present disclosure, in the lens unit according to the first aspect or the second aspect, the inner wall may be provided rotationally symmetrically about the optical axis.

According to the lens unit according to the third aspect of the present disclosure, it is possible to cancel the force that the lens receives from the lens barrel, and to prevent the center of the optical axis of the lens from shifting.

The lens unit according to the fourth aspect of the present disclosure may be a resin lens made of resin in the lens unit according to any one of the first to third aspects.

According to the lens unit according to the fourth aspect of the present disclosure, the resin lens has a larger thermal expansion than the lens barrel. In this case, the resin lens is thermally expanded toward the lens barrel side, but the reaction force acting on the lens from the lens barrel is reduced and the optical characteristics are favorably maintained by bending and deforming the inner wall of the lens barrel toward the cavity side. be able to. Further, in the lens unit according to the fourth aspect, the moldability can be improved as compared with the glass lens made of glass, the degree of design freedom can be increased, and the cost is lower than when the glass lens is used. Can be reduced.

In the lens unit according to the fifth aspect of the present disclosure, in the lens unit according to the fourth aspect, the hollow portion may be filled with a filler made of a material having a Young's modulus lower than that of the lens barrel.

According to the lens unit according to the fifth aspect of the present disclosure, the amount of bending deformation of the inner wall can be limited by the filler. As a result, in the lens unit according to the fifth aspect, even when the inner wall is formed thin, it is possible to prevent the inner wall from breaking due to a large amount of deformation of the inner wall during thermal expansion.

A lens unit according to a sixth aspect of the present disclosure is the lens unit according to any one of the first aspect to the third aspect. The lens is a glass lens made of glass, and the hollow portion includes a lens barrel. Alternatively, a filler having a high linear expansion coefficient may be filled.

According to the lens unit according to the sixth aspect of the present disclosure, since the thermal expansion of the lens barrel is larger than that of the glass lens, the holding power of the glass lens is reduced, while the inner wall of the lens barrel bulges to the glass lens side. Therefore, a change in force acting on the contact portion between the lens barrel and the lens can be suppressed. In the lens unit according to the sixth aspect, the inner wall can be further bulged toward the glass lens side due to the thermal expansion of the filler, and the optical characteristic is prevented from changing due to the optical axis shift of the glass lens. it can.

A lens unit according to a seventh aspect of the present disclosure is the lens unit according to any one of the first to sixth aspects. The lens is in contact with three or more inner walls when viewed from the optical axis direction. May be.

According to the lens unit according to the seventh aspect of the present disclosure, the positional accuracy when the lens is assembled to the lens barrel as compared with the case where the lens is in contact with two or less inner walls when viewed from the optical axis direction. Can be improved.

In the lens unit according to the eighth aspect of the present disclosure, in the lens unit according to any one of the first aspect to the seventh aspect, the inner peripheral surface of the barrel may be polygonal.

According to the lens unit according to the eighth aspect of the present disclosure, the portions corresponding to the inner wall of the mold for forming the lens barrel can be separately surfaced, so that the dimensional accuracy of the inner wall in contact with the lens can be increased. Easy to improve.

A lens unit according to a ninth aspect of the present disclosure is the lens unit according to any one of the first to seventh aspects. The contact portion of the inner wall with the lens is viewed from the optical axis direction. A curved surface that is recessed radially outward of the lens barrel and that makes surface contact with the lens may be formed.

According to the lens unit according to the ninth aspect of the present disclosure, the optical axis shift caused by distortion of the outer diameter of the lens, by receiving the lens with a plurality of curved surfaces, as compared with the configuration in which the lens is received with a point. The optical characteristic defect from can be suppressed.

In the lens unit according to the tenth aspect of the present disclosure, in the lens unit according to any one of the first to ninth aspects, the cavity may be closed by the inner wall and the outer wall when viewed from the optical axis direction. .

According to the lens unit according to the tenth aspect of the present disclosure, the strength of the inner wall can be increased as compared with the structure in which the hollow portion is opened to the inner wall side. In the lens unit according to the tenth aspect, the strength of the outer wall can be increased as compared with the structure in which the cavity is open to the outer wall side.

In the lens unit according to the eleventh aspect of the present disclosure, in the lens unit according to the tenth aspect, the cavity may be provided within a predetermined range of 45 degrees around the optical axis.

According to the lens unit according to the eleventh aspect of the present disclosure, the strength of the inner wall and the outer wall can be improved as compared with the case where the cavity is formed beyond the range of 45 degrees around the optical axis.

A lens unit according to a twelfth aspect of the present disclosure is the lens unit according to any one of the first to eleventh aspects, wherein a plurality of lenses are arranged along the optical axis direction inside the lens barrel. The lens barrel may be provided with an inner wall and an outer wall for a plurality of lenses.

According to the lens unit according to the twelfth aspect of the present disclosure, the optical characteristics can be favorably maintained for a plurality of lenses even when the external temperature is increased.

A lens unit according to a thirteenth aspect of the present disclosure is the lens unit according to the twelfth aspect, wherein the plurality of lenses have different outer diameters, and the inner peripheral surface of the lens barrel is an object according to the outer diameter of the lens. The diameter is increased or decreased from the side toward the image side, and a plurality of hollow portions may be provided at different positions in the radial direction of the lens barrel.

According to the lens unit according to the thirteenth aspect of the present disclosure, even when a plurality of lenses having different outer diameters are used, the force from the lens barrel acting on each lens can be made the same level.

The lens unit according to the fourteenth aspect of the present disclosure is the lens unit according to any one of the first aspect to the thirteenth aspect, and the lens unit may be a vehicle-mounted or monitoring lens unit.

According to the lens unit according to the fourteenth aspect of the present disclosure, in a lens unit used in an environment where it is likely to be exposed to high temperatures and it is difficult to maintain imaging performance, such as a monitoring camera or a vehicle-mounted camera. However, performance degradation can be reduced.

According to the above aspect of the present disclosure, it is possible to provide a lens unit that can ensure the strength of the lens barrel while maintaining good optical characteristics even when the external temperature is increased.

1 is an overall configuration diagram of a lens unit according to an exemplary embodiment. FIG. 2 is an enlarged cross-sectional view of a cut surface cut along line 2-2 in FIG. It is sectional drawing corresponding to FIG. 2 at the time of thermal expansion. It is an expanded sectional view of a lens barrel showing the 1st modification of a lens unit concerning an exemplary embodiment. It is an expanded sectional view of a lens barrel showing the 2nd modification of a lens unit concerning an exemplary embodiment. It is sectional drawing corresponding to FIG. 2 which shows the 3rd modification of the lens unit which concerns on exemplary embodiment. It is sectional drawing corresponding to FIG. 2 which shows the 4th modification of the lens unit which concerns on exemplary embodiment. It is sectional drawing corresponding to FIG. 2 which shows the 5th modification of the lens unit which concerns on exemplary embodiment.

Hereinafter, exemplary embodiments according to the present disclosure will be described with reference to the drawings. In the drawings, components having the same function are denoted by the same reference numerals, and description thereof will be omitted as appropriate. Moreover, S shown suitably in each figure shows an optical axis, and the direction along the optical axis S is described as an optical axis direction.

As shown in FIG. 1, the imaging device 100 includes a lens unit 10 and an imaging module 110. The imaging module 110 includes an imaging element 112 such as a CMOS (Complementary Metal Oxide Semiconductor) image sensor or a CCD (Charge Coupled Device) image sensor. The imaging element 112 is provided at an imaging point of the optical system of the lens unit 10. Be placed. The imaging module 110 is supported by a holder (not shown), and this holder is attached to the lens unit 10.

(Entire configuration of lens unit)
The lens unit 10 according to the present exemplary embodiment includes an optical system including a plurality of lenses and a lens barrel 50 that houses the optical system. The optical system includes a first lens 12, a second lens 14, a third lens 16, a fourth lens 18, and a fifth lens 20 arranged in order from the object side (incident side).

The first lens 12 is disposed on the most object side, and includes a lens part 12A having an optical surface and a peripheral part 12B that constitutes the outer peripheral part of the lens part 12A. The first lens 12 is a glass lens formed of glass, and the object side surface of the lens portion 12A is curved so as to be convex toward the object side. Further, the first lens 12 is formed with a step so that the image side (imaging module 110 side) is smaller in diameter than the object side, and the large-diameter portion on the object side in the peripheral edge portion 12B is formed on the lens barrel 50. It is in contact with the inner peripheral surface. On the other hand, an O-ring 22 that is a sealing material is disposed around the small-diameter portion on the image side in the peripheral portion 12B. The O-ring 22 seals between the small diameter portion of the peripheral edge portion 12B and the inner peripheral surface of the lens barrel 50.

The second lens 14 is disposed on the image side of the first lens 12 with a space coaxially with the first lens 12. The second lens 14 is a glass lens similar to the first lens 12, and includes a lens portion 14A having an optical surface and a peripheral portion 14B constituting the outer peripheral portion of the lens portion 14A. The second lens 14 has a smaller outer diameter than the first lens 12. Specifically, the outer diameter of the second lens 14 is smaller than the large diameter portion of the first lens 12 and larger than the small diameter portion of the first lens 12. Further, the image side surface of the lens portion 14 A is curved so as to be convex toward the image side, and the peripheral portion 14 B is in contact with the inner peripheral surface of the lens barrel 50.

The third lens 16 is arranged on the image side of the second lens 14 with a space coaxially with the second lens 14. The third lens 16 is a resin lens made of resin, and has the same outer diameter as that of the second lens 14. The third lens 16 includes a lens portion 16A having an optical surface and a peripheral edge portion 16B constituting the outer peripheral portion of the lens portion 16A, and the object side surface of the lens portion 16A is convex toward the object side. It is curved to be. Further, the peripheral edge portion 16 B of the third lens 16 is in contact with the inner peripheral surface of the lens barrel 50.

A fourth lens 18 is disposed coaxially with the third lens 16 on the image side of the third lens 16. The fourth lens 18 is a resin lens made of resin, and is formed with an outer diameter substantially the same as that of the third lens 16. The fourth lens 18 includes a lens portion 18A having an optical surface and a peripheral edge portion 18B that constitutes the outer peripheral portion of the lens portion 18A. The lens portion 18A is curved so that both the object side surface and the image side surface are convex. Further, the peripheral edge portion 18B of the fourth lens 18 is in contact with the peripheral edge portion 16B of the third lens 16 in the optical axis direction, and is in contact with the inner peripheral surface of the lens barrel 50.

The fifth lens 20 is arranged on the image side of the fourth lens 18 with a space coaxially with the fourth lens 18. The fifth lens 20 is a resin lens made of resin and has a smaller outer diameter than the third lens 16 and the fourth lens 18. The fifth lens 20 includes a lens portion 20A having an optical surface and a peripheral portion 20B that constitutes the outer peripheral portion of the lens portion 20A. The object side surface of the lens unit 20A is curved so as to be convex toward the object side. Further, the peripheral edge portion 20 B of the fifth lens 20 is in contact with the inner peripheral surface of the lens barrel 50.

Here, a first spacing ring 24 is disposed between the first lens 12 and the second lens 14, and a second spacing ring 26 is disposed between the second lens 14 and the third lens 16. The third spacing ring 30 is disposed between the fourth lens 18 and the fifth lens 20.

The first spacing ring 24 is formed in a substantially annular shape, and the outer peripheral surface is in contact with the inner peripheral surface of the lens barrel 50. Further, an opening 24A is formed on the object side of the first spacing ring 24, and the hole wall of the opening 24A is formed in a tapered shape so as to be positioned radially inward from the object side toward the image side. ing. On the other hand, an opening 24B having a smaller diameter than the opening 24A is formed on the image side of the first spacing ring 24. The hole wall of the opening 24B is formed in a tapered shape so as to be positioned radially inward from the object side toward the image side. Furthermore, the end of the first spacing ring 24 on the object side is in contact with the peripheral edge 12B of the first lens 12, and the end of the first spacing ring 24 on the image side is the peripheral edge of the second lens 14. 14B.

The second spacing ring 26 is formed in a substantially annular shape, and the outer peripheral surface is in contact with the inner peripheral surface of the lens barrel 50. Moreover, the opening part 26A is formed in the 2nd space | interval ring 26, and the hole wall of 26 A of opening parts is extended along the optical axis direction. Further, a protrusion 26B protruding radially inward is formed on the hole wall of the opening 26A. The end of the second spacing ring 26 on the object side is in contact with the peripheral edge 14 B of the second lens 14, and the end of the second spacing ring 26 on the image side is the peripheral edge of the third lens 16. It is in contact with 16B.

The third spacing ring 30 is formed in a substantially annular shape, and the outer peripheral surface is in contact with the inner peripheral surface of the lens barrel 50. Further, an opening 30 A is formed in the third spacing ring 30. The hole wall of the opening 30A extends along the optical axis direction, and the image side of the hole wall is reduced in diameter in the radial direction. Further, the end of the third spacing ring 30 on the object side is in contact with the peripheral edge 18B of the fourth lens 18, and the end of the third spacing ring 30 on the image side is the peripheral edge of the fifth lens 20. It is in contact with 20B. The optical system of the lens unit 10 is configured as described above, and the position of each lens in the optical axis direction is determined by the first spacing ring 24, the second spacing ring 26, and the third spacing ring 30.

(Configuration of the lens barrel 50)
Next, a configuration of the lens barrel 50 that is a main part of the present disclosure will be described.

The lens barrel 50 of the present exemplary embodiment is formed in a substantially cylindrical shape with both ends opened, and is formed by resin molding. In addition, a bottom portion 52 that extends radially inward from the inner peripheral surface of the lens barrel 50 is provided at the end of the lens barrel 50 on the image side. A through hole 50A having an optical aperture function is formed in the bottom portion 52, and the peripheral portion 20B of the fifth lens 20 is in contact with the object side surface of the bottom portion 52.

Here, as an example, the lens barrel 50 may be made of polyphenylene sulfide containing glass fiber and an inorganic filler. By making the lens barrel made of fiber reinforced plastic containing glass fiber or the like, the mechanical strength is increased. Examples of the resin used include polyamide, polyacetal, polycarbonate, polyphenylene ether, polybutylene terephthalate, polyethylene terephthalate, polyethylene, syndiotactic polystyrene, polysulfone, polyethersulfone, polyphenylene sulfide, polyarylate, polyamideimide, and polyether. It is possible to use at least one selected from the group consisting of imide, polyetheretherketone, acrylonitrile butadiene styrene, polyolefin and each modified polymer, or a polymer alloy containing at least one selected from the group. As the fiber, glass fiber, carbon fiber, fiber reinforced plastic, inorganic filler, or the like can be used.

In addition, the above resin material such as fiber reinforced plastic may contain glass fiber, carbon fiber, inorganic filler or the like, if necessary. By using a fiber reinforced plastic lens barrel containing glass fiber or the like, a lens barrel with higher mechanical strength can be obtained.

Note that the lens barrel is required to have high light-shielding properties and light-absorbing properties. The resin used is preferably black, and the resin material preferably contains a black pigment or a black dye. By constituting the lens barrel with a resin material containing a black pigment or black dye, the inner wall surface of the lens barrel can be made black, and reflection of visible light on the inner wall surface of the lens barrel can be more effectively suppressed. .

A crimping portion 50B is formed at the end of the lens barrel 50 on the object side. The caulking portion 50B is formed by heat caulking the end of the lens barrel 50 on the object side, and the caulking portion 50B prevents the optical system components from being detached from the lens barrel 50. In addition, an opening 50C through which light is incident is formed at the center portion of the crimping portion 50B.

Here, the lens barrel 50 includes a first step portion 58, a second step portion 56, and a third step portion 54 in order from the object side, and the inner portion of the lens barrel 50 at the boundary portion of each step portion. A step is formed on the peripheral surface. The first step portion 58 is formed from the end of the lens barrel 50 on the object side to the position of the second lens 14, and the inner diameter of the lens barrel 50 is the largest. Further, the first step portion 58 is formed in a circular shape or a polygonal shape as viewed from the optical axis direction, and the peripheral portion 12B of the first lens 12 is formed on the inner peripheral surface of the lens barrel 50 in the first step portion 58. It is in contact.

The second step portion 56 is formed from the position of the second lens 14 to the position of the fifth lens 20, and the inner diameter of the lens barrel 50 is smaller than that of the first step portion 58. Further, the inner peripheral surface of the lens barrel 50 in the second step portion 56 is formed in a substantially octagonal shape as viewed from the optical axis direction, as shown in FIG. Specifically, the inner peripheral surface of the lens barrel 50 in the second step portion 56 is formed by connecting the eight flat surfaces forming the sides of the octagon and the adjacent flat surfaces (the corner portions in FIG. 2). ). A plurality of peripheral edges 14B of the second lens 14, peripheral edges 16B of the third lens 16, and peripheral edges 18B of the fourth lens 18 are provided on the inner peripheral surface of the lens barrel 50 in the second step portion 56 in the circumferential direction. It touches at the place. Note that reference numeral 16 C in FIG. 2 is a gate portion formed in the third lens 16.

As shown in FIG. 1, the third step portion 54 is formed from the position of the fifth lens 20 to the bottom portion 52, and the inner diameter of the lens barrel 50 is smaller than that of the second step portion 56. Further, the inner peripheral surface of the lens barrel 50 in the third step portion 54 is formed in a substantially octagonal shape when viewed from the optical axis direction, like the second step portion 56, and the lens barrel 50 in the third step portion 54. The peripheral edge portion 20B of the fifth lens 20 is in contact with the inner peripheral surface at a plurality of locations in the circumferential direction.

Since the first step portion 58, the second step portion 56, and the third step portion 54 are formed as described above, the inner peripheral surface of the lens barrel 50 is reduced in diameter from the object side toward the image side. Yes. When the lens unit 10 is manufactured, the fifth lens 20, the third interval ring 30, the fourth lens 18, the third lens 16, the second interval ring 26, the second lens 14, the first interval ring 24, the first lens. Each part is press-fitted into the lens barrel 50 in the order of twelve, and then the object-side end portion of the lens barrel 50 is thermally crimped. In addition, a spacer or the like as a light shielding plate may be arranged.

Here, the lens barrel 50 is provided with a plurality of hollow portions 60. As an example, the cavity 60 of the exemplary embodiment is in the direction of the optical axis from the image-side end of the lens barrel 50 to a position between the third lens 16 and the second lens 14 (position of the second spacing ring 26). Is extended along.

As shown in FIG. 2, the third lens 16 is in contact with the second step portion 56 (inner peripheral surface) of the lens barrel 50 at a plurality of locations, and as an example in the present exemplary embodiment, at eight locations. It is in contact. The cavity portion 60 is provided on the outer side in the radial direction of the contact portion P with the third lens 16 in the lens barrel 50. In the present exemplary embodiment, eight cavity portions 60 are provided when viewed from the optical axis direction. It has been. The lens barrel 50 includes an inner wall 62 and an outer wall 64 that are opposed to each other in the radial direction across the cavity 60. In other words, the cavity 60 is provided between the inner wall 62 and the outer wall 64.

The inner walls 62 are provided so as to be rotationally symmetric about the optical axis S, and are provided at equal intervals around the optical axis S when viewed from the optical axis direction. Further, the eight hollow portions 60 are formed in substantially the same shape, and the length from the optical axis S to each hollow portion 60 is also substantially the same. For this reason, the pair of inner walls 62 facing each other with the optical axis S interposed therebetween have the same radial thickness.

Here, the relationship between the thickness of the inner wall 62 and the thickness of the outer wall 64 is such that the outer wall 64 is thicker in the radial direction than the inner wall 62. Specifically, the thickness T3 of the outer wall 64 is formed to be thicker than the thickness T1 of the inner wall 62 on the imaginary line connecting the optical axis S (center of the lens barrel 50) and the contact portion P.

Moreover, the radial thickness of the outer wall 64 is formed to be thicker than the radial interval between the inner wall 62 and the outer wall 64. Specifically, on the imaginary line connecting the optical axis S of the third lens 16 and the contact portion P, the thickness T3 of the outer wall 64 is the radial distance between the inner wall 62 and the outer wall 64 (the diameter of the cavity 60). (Width in the direction) is formed thicker than T2.

Furthermore, the hollow portion 60 is provided within a predetermined range of 45 degrees around the optical axis S. Specifically, a cavity is formed in a region between the imaginary line L1 and the imaginary line L2 that is extended so as to pass through the corner of the inner peripheral surface of the lens barrel 50 at an interval of 45 degrees from the optical axis S when viewed from the optical axis direction. A portion 60 is provided. Furthermore, the cavity 60 is closed by the inner wall 62 and the outer wall 64 when viewed from the optical axis direction. That is, the communication hole etc. which connect with the cavity part 60 are not formed in the inner wall 62 and the outer wall 64 seeing from the optical axis direction, but the cavity part 60 is obstruct | occluded.

In the exemplary embodiment, as an example, when the lens barrel 50 is molded, the mold part corresponding to the lens housing portion and the mold part corresponding to the cavity 60 are slid from the image side from the image side. Thus, the cavity 60 is formed. In the exemplary embodiment, only the hollow portion 60 provided on the radially outer side of the contact portion P between the third lens 16 and the lens barrel 50 has been described. However, a common cavity 60 is also provided on the radially outer side of the contact portion between the fourth lens 18 and the lens barrel 50, and the radially outer side of the contact portion between the fifth lens 20 and the lens barrel 50 is provided. In addition, a common cavity 60 is provided. That is, the lens barrel 50 is provided with an inner wall 62 and an outer wall 64 for a plurality of lenses (see FIG. 1).

(Function and effect)
Next, operations and effects of the exemplary embodiment will be described.

In the present exemplary embodiment, as shown in FIG. 2, a plurality of circumferential locations in the lens barrel 50 are opposed to the inner wall 62 and the inner wall 62 in the radial direction across the cavity 60 and more than the inner wall 62. And an outer wall 64 having a large radial thickness. That is, in the exemplary embodiment, the cavity 60 is provided on the outer side in the radial direction from the contact portion P with the third lens 16 in the lens barrel 50. The cavity 60 is located between the inner wall 62 and the outer wall 64. Here, a case where the lens unit 10 is thermally expanded due to an increase in external temperature or the like will be considered.

In this case, since the third lens 16 that is a resin lens is more thermally expanded than the lens barrel 50, a radially outward force acts on the inner wall 62 of the lens barrel 50 from the third lens 16. Here, in this exemplary embodiment, as shown in FIG. 3, the reaction force acting on the third lens 16 from the inner wall 62 due to the inner wall 62 being bent and deformed toward the cavity 60 is reduced. That is, the force from the third lens 16 is absorbed. As a result, the deformation of the third lens 16 can be suppressed, and the optical characteristics can be maintained well. Similarly, the fourth lens 18 and the fifth lens 20 are also provided with the inner wall 62, so that deformation of the lens due to thermal expansion can be suppressed. That is, this exemplary embodiment can maintain good optical characteristics for a plurality of lenses even when the external temperature is increased.

In the exemplary embodiment, as shown in FIG. 2, the outer wall 64 is formed to have a greater radial thickness than the inner wall 62. This ensures the strength of the outer wall 64 as compared with the case where the radial thickness T3 of the outer wall 64 is the same as the radial thickness T1 of the inner wall 62 or thinner than the radial thickness T1 of the inner wall 62. Can do. As described above, this exemplary embodiment can ensure the strength of the lens barrel 50 while maintaining good optical characteristics.

Furthermore, in the exemplary embodiment, the outer wall 64 is formed to be thicker in the radial direction than the radial interval T2 between the inner wall 62 and the outer wall 64. Thereby, this exemplary embodiment can improve the intensity | strength of the outer wall 64 compared with the case where the thickness T3 of the radial direction of the outer wall 64 is the same as the space | interval T2, or is thinner than the space | interval T2. That is, in the exemplary embodiment, when the lens unit 10 is fastened to a holder or a bracket (not shown), the deformation of the lens barrel 50 is suppressed even if an external force is applied from the holder or the bracket. The lens unit 10 can be used for various purposes.

Furthermore, in the present exemplary embodiment, the plurality of cavities 60 are provided rotationally symmetrically about the optical axis S, and the pair of inner walls 62 opposed across the optical axis S have the same thickness in the radial direction. It is said that. Thereby, this exemplary embodiment can cancel the force that the third lens 16 receives from the lens barrel 50, and can suppress the center of the optical axis of the third lens 16 from deviating.

In the exemplary embodiment, a resin lens is used for at least one of the lenses constituting the lens unit 10 (the third lens 16, the fourth lens 18, and the fifth lens 20). Thereby, this exemplary embodiment can improve a moldability compared with a glass lens, and can raise a design freedom. Moreover, this exemplary embodiment can reduce cost rather than the case where all the lenses are made of glass.

Further, in the exemplary embodiment, the third lens 16 is in contact with the eight inner walls 62 as viewed from the optical axis direction. Thereby, this exemplary embodiment can improve the positional accuracy when the lens is assembled to the lens barrel 50 as compared with the case where the third lens 16 is in contact with two or less inner walls 62. . In particular, by making the inner peripheral surface of the lens barrel 50 octagonal (polygonal) as in this exemplary embodiment, the contact portion P between the third lens 16 and the lens barrel 50 becomes a flat surface. For this reason, in this exemplary embodiment, surface projection is easier than in the case where the lens is held by a curved surface like a lens barrel having a circular inner peripheral surface, and dimensional accuracy is easily improved.

Furthermore, in this exemplary embodiment, since the cavity 60 is closed by the inner wall 62 and the outer wall 64 when viewed from the optical axis direction, the inner wall is compared with the structure in which the cavity 60 is opened to the inner wall 62 side. The strength of 62 can be increased. In addition, the strength of the outer wall 64 can be increased as compared with the structure in which the hollow portion 60 is opened to the outer wall 64 side. In the exemplary embodiment, since the cavity 60 is formed within a predetermined range of 45 degrees around the optical axis S, the cavity 60 does not become too large, and the strength of the inner wall 62 and the outer wall 64 is increased. It can be improved effectively.

As described above, the exemplary embodiment has been described. However, as another modified example, the shape of the cavity may be different as in the first modified example illustrated in FIG. 4 or the second modified example illustrated in FIG. 5. . Further, the shape of the inner peripheral surface of the lens barrel may be different as in the third modified example shown in FIG. 6 and the fourth modified example shown in FIG. Furthermore, you may fill a cavity with a filler like the 5th modification shown by FIG. In the following description of the modified examples, the same reference numerals are given to the same configurations as those of the exemplary embodiment, and description thereof will be omitted as appropriate.

(First modification)
As shown in FIG. 4, the lens barrel 50 constituting the lens unit 65 according to the first modification includes a first step portion (not shown), a second step portion 56, and a third step, as in the exemplary embodiment. Part 54. 4 and 5, only a part of the lens barrel 50 is shown for convenience of explanation, and illustration of the lens is omitted. Further, only one side from the optical axis S in the cross section of the lens barrel 50 is shown, and the other side from the optical axis S is not shown.

Here, a hollow portion 66 is formed in the second step portion 56 and the third step portion 54. The cavity portion 66 extends along the optical axis direction, and includes a wide portion 66A on the image side and a narrow portion 66B on the object side. The wide width portion 66A and the narrow width portion 66B are formed continuously in the optical axis direction, and the narrow width portion 66B is formed with the same width in the radial direction as the cavity portion 60 of the exemplary embodiment.

On the other hand, the wide portion 66A is formed from the boundary portion between the second step portion 56 and the third step portion 54 to the bottom portion (not shown) of the lens barrel 50, and has a larger radial width than the narrow width portion 66B. Is formed. Specifically, the wide portion 66 A is formed wider on the inner side by the level difference located at the boundary portion between the second step portion 56 and the third step portion 54.

In the first modified example configured as described above, even when the inner peripheral surface of the lens barrel 50 is reduced in diameter as it goes from the object side to the image side, the thickness of the inner wall 62 and the outer wall 64 is set to the optical axis. Can be constant in direction.

(Second modification)
As shown in FIG. 5, the lens barrel 50 constituting the lens unit 67 according to the second modification includes a first step portion (not shown), a second step portion 56, and a third step as in the exemplary embodiment. Part 54.

Here, in this modification, a plurality of cavities are provided at different positions in the radial direction of the lens barrel 50. Specifically, a first cavity portion 70 is formed in the second step portion 56, and a second cavity portion 68 is formed in the third step portion 54. The first cavity portion 70 is formed from the boundary portion between the second step portion 56 and the third step portion 54 to the boundary portion between the first step portion and the second step portion 56.

On the other hand, the second cavity portion 68 is formed from the boundary portion between the second step portion 56 and the third step portion 54 to the bottom portion (not shown) of the lens barrel 50. Further, the second cavity portion 68 is formed on the radially inner side with respect to the first cavity portion 70. The inner wall 62 inside the first cavity portion 70 and the inner wall 62 inside the second cavity portion 68 have the same thickness in the radial direction. That is, the radial thickness of the inner wall 62 with which one lens abuts is the same as the radial thickness of the inner wall 62 with which another lens with a different outer diameter abuts.

In the second modified example configured as described above, as in the first modified example, even when the inner peripheral surface of the lens barrel 50 is reduced in diameter from the object side toward the image side, the inner wall 62 Can be made constant in the optical axis direction. In addition, the outer wall 64 in the third step portion 54 can be formed thicker than in the first modification. The first cavity portion 70 and the second cavity portion 68 may be formed by sliding the mold portions corresponding to the first cavity portion 70 and the second cavity portion 68 when the lens barrel 50 is injection molded. it can.

(Third Modification)
As shown in FIG. 6, the lens barrel 74 constituting the lens unit 72 according to the third modified example is provided with eight hollow portions 60 as in the exemplary embodiment. The third lens 16 is disposed inside the lens barrel 74, and the third lens 16 and the lens barrel 74 are in contact with each other at eight contact portions P.

Here, in this modification, the eight flat surfaces forming each side of the inner peripheral surface of the lens barrel 74 are curved surfaces that protrude radially inward. For this reason, the inner wall 62 inside the cavity 60 is bulged radially inward. Other configurations are the same as those of the exemplary embodiment, and this modification has the same effects as those of the exemplary embodiment.

(Fourth modification)
Next, in the fourth modification example, as shown in FIG. 7, the lens barrel 76 constituting the lens unit 75 is provided with eight inner walls 82, and these inner walls 82 are centered on the optical axis S. As rotationally symmetric. Each of the inner walls 82 is formed to be shorter in the circumferential direction than the inner wall 62 of the above exemplary embodiment, and is curved in a surface contact with the third lens 16 by being recessed radially outward when viewed from the optical axis direction. It has a surface. Further, the third lens 16 is disposed inside the lens barrel 76, and the third lens 16 is in contact with the contact portions P respectively set on the eight inner walls 82. The cavity portion 78 is provided on the radially outer side of the contact portion P, and is located between the inner wall 82 and the outer wall 84. In addition, the relationship of the radial thickness of the inner wall 82 and the outer wall 84 is the same as that of the above exemplary embodiment.

Here, the inner peripheral surface of the lens barrel 76 is configured to include a plurality (eight) curved surfaces curved outward in the radial direction and eight concave portions 80 formed between adjacent flat surfaces. . More specifically, the curved surfaces constituting the inner peripheral surface of the lens barrel 76 are provided at equal intervals around the optical axis S, and constitute the radially inner surface of the inner wall 82. The eight curved surfaces are formed with the same length as viewed from the optical axis direction. The third lens 16 is in contact with this curved surface.

The recess 80 is formed by denting a portion between adjacent flat surfaces outward in the radial direction. Other configurations are the same as those in the exemplary embodiment. In this modification, by receiving the lens with a plurality of curved surfaces, the contact area with the lens can be increased as compared with the configuration in which the lens is received with a point as in the above exemplary embodiment. As a result, it is possible to suppress an optical characteristic defect from an optical axis shift caused by distortion of the outer diameter of the lens. Others have the same effects as the above exemplary embodiment.

(5th modification)
Next, in the fifth modified example, as shown in FIG. 8, a filler 92 is filled in the hollow portion 60 of the lens barrel 50 constituting the lens unit 90. The filler 92 is formed of a material having a Young's modulus lower than that of the material constituting the lens barrel 50.

Here, the filler 92 can be selected from the same material group as the lens barrel 50. Moreover, the Young's modulus and the linear expansion coefficient of the filler 92 can be adjusted by changing the ratio of the inorganic substance contained in the resin or changing the resin.

In this modification, the amount of bending deformation of the inner wall 62 can be limited by the filler 92. That is, the amount of flexural deformation of the inner wall 62 is small as compared to a structure in which nothing is filled in the cavity 60 (a structure containing air) as in the exemplary embodiment. As a result, even when the inner wall 62 is formed thin, it is possible to prevent the inner wall 62 from being broken due to a large amount of deformation of the inner wall 62 during thermal expansion.

As mentioned above, although exemplary embodiment and modification of this indication were explained, this indication is not limited to the above-mentioned exemplary embodiment and modification, and can change variously in the range which does not deviate from a gist. For example, in the above exemplary embodiment, the third lens 16, the fourth lens 18, and the fifth lens 20 are resin lenses, but the present invention is not limited thereto, and glass lenses may be used.

(When the third lens 16 is a glass lens)
If the third lens 16 is a glass lens, the thermal expansion of the lens barrel 50 is larger than that of the third lens 16. For this reason, when the external temperature rises, the holding force of the third lens 16 decreases, and the inner wall 62 bulges toward the third lens 16, so that the contact portion P between the lens barrel 50 and the third lens 16. It is possible to suppress a change in force acting on the.

Further, when a glass lens is used as the third lens 16, the linear expansion coefficient is higher than the material constituting the lens barrel 50 in the cavity portion 60 of the fifth modification shown in FIG. 8 instead of the filler 92. A filler may be filled. In this case, the filler filled in the cavity portion 60 is thermally expanded, so that the inner wall 62 of the lens barrel 50 is further bulged toward the third lens 16, and the third lens 16 is displaced from the optical axis, resulting in optical characteristics. The change can be suppressed.

In the exemplary embodiment and the modification described above, eight contact portions P between the lens and the lens barrel 50 are used, but the present invention is not limited to this. For example, the inner peripheral surface of the lens barrel 50 may be a hexagon or more and nine or more contact portions P may be provided. On the contrary, you may comprise so that the contact part P may be seven or less. As shown in FIG. 2, in the exemplary embodiment, the gate portion 16 C is positioned between adjacent flat surfaces, but the third lens is positioned so that the gate portion 16 C is positioned at a position facing the flat surface. If 16 is arranged, there will be seven contact portions P. Even in this case, there is an effect of suppressing the change of the optical characteristics due to the deformation of the third lens 16 and the optical axis deviation at the time of thermal expansion.

Furthermore, in the exemplary embodiment and the modification described above, the inner peripheral surface of the lens barrel 50 is reduced in diameter as it goes from the object side to the image side. However, the present invention is not limited thereto, and the inner peripheral surface of the lens barrel 50 is the object. The diameter may be increased from the side toward the image side. In this case, a lens having a larger outer diameter on the image side than on the object side is disposed.

Furthermore, in the exemplary embodiment, as shown in FIG. 2, the inner peripheral surface of the lens barrel 50 is connected to the eight flat surfaces forming the sides of the octagon and the adjacent flat surfaces. (Corner part) It comprised, but it is not limited to this. For example, it is good also as a structure which connected between the adjacent flat surfaces by the substantially circular arc-shaped connection part. In this case, stress concentration can be suppressed as compared with a configuration in which the connecting portion is a corner portion.

In the above exemplary embodiment, the shape of the cavity 60 is formed in a substantially rectangular shape when viewed from the optical axis direction, but is not limited thereto. For example, the cavity 60 may be formed in a substantially oval shape or a substantially oval shape when viewed from the optical axis direction. In this case, “the radial thickness of the inner wall” in the present disclosure is the thickness of the inner wall on the imaginary line connecting the optical axis S and the contact portion P. Similarly, the “thickness in the radial direction of the outer wall” in the present disclosure is the thickness of the outer wall on an imaginary line connecting the optical axis S and the contact portion P. Further, the “radial distance between the inner wall and the outer wall” in the present disclosure is the width of the hollow portion 60 on the imaginary line connecting the optical axis S and the contact portion P.

Furthermore, in this exemplary embodiment, the hollow portion 60 is provided on the radially outer side of all the contact portions P, but the present invention is not limited to this. For example, four cavities 60 may be provided at intervals of 90 degrees around the optical axis S when viewed from the optical axis direction, and the cavities 60 may be appropriately formed according to the strength against external force required for the lens barrel 50. The size and number may be changed.

Furthermore, in this exemplary embodiment, the cavity 60 is closed by the inner wall 62 and the outer wall 64 when viewed from the optical axis direction, but is not limited thereto. For example, a communication hole that communicates with the cavity 60 may be provided in the inner wall 62. In this case, the inner wall 62 is cantilevered when viewed from the optical axis direction. However, a structure in which the cavity 60 is closed is preferable from the viewpoint of securing the strength of the inner wall 62.

The entire disclosure of Japanese Application 2016-0665655 is incorporated herein by reference.

All documents, patent applications, and technical standards mentioned in this specification are to the same extent as if each individual document, patent application, and technical standard were specifically and individually described to be incorporated by reference, Incorporated herein by reference.

Claims

A resin that is formed in a cylindrical shape and includes a plurality of circumferential walls including an inner wall and an outer wall that is opposed to the inner wall in a radial direction with a hollow portion interposed therebetween and is thicker in the radial direction than the inner wall. A lens barrel,
A lens abutting against the plurality of inner walls and fitted into the lens barrel;
A lens unit.
2. The lens unit according to claim 1, wherein a radial thickness of the outer wall is thicker than a radial interval between the inner wall and the outer wall.
3. The lens unit according to claim 1, wherein the inner wall is provided rotationally symmetrically about the optical axis.
The lens unit according to any one of claims 1 to 3, wherein the lens is a resin lens made of resin.
The lens unit according to claim 4, wherein the hollow portion is filled with a filler made of a material having a Young's modulus lower than that of the material constituting the lens barrel.
The lens is a glass lens made of glass,
The lens unit according to any one of claims 1 to 3, wherein the hollow portion is filled with a filler having a higher linear expansion coefficient than a material constituting the lens barrel.
The lens unit according to any one of claims 1 to 6, wherein the lens is in contact with three or more inner walls as viewed from the optical axis direction.
The lens unit according to any one of claims 1 to 7, wherein an inner peripheral surface of the lens barrel has a polygonal shape.
8. A curved surface that is indented radially outward of the lens barrel when viewed from the optical axis direction and is in surface contact with the lens is formed at a contact portion of the inner wall with the lens. The lens unit according to any one of the above.
The lens unit according to any one of claims 1 to 9, wherein the cavity is closed by the inner wall and the outer wall when viewed from the optical axis direction.
The lens unit according to any one of claims 1 to 10, wherein the hollow portion is provided within a predetermined range of 45 degrees around the optical axis.
Inside the lens barrel, a plurality of the lenses are arranged along the optical axis direction,
The lens unit according to any one of claims 1 to 11, wherein the lens barrel is provided with the inner wall and the outer wall with respect to a plurality of the lenses.
The plurality of lenses have different outer diameters,
The inner peripheral surface of the lens barrel is enlarged or reduced in diameter as it goes from the object side to the image side according to the outer diameter of the lens,
The lens unit according to claim 12, wherein a plurality of the cavity portions are provided at different positions in the radial direction of the lens barrel.
The lens unit according to any one of claims 1 to 13, wherein the lens unit is an in-vehicle or monitoring lens unit.