Lens unit and camera module

Abstract

To provide a lens unit and a camera module that can regulate lens decentration from an optical axis by correctly centering and positioning a lens in a lens tube and without causing the lens and lens tube to be in direct contact with each other.SOLUTION: A lens unit 11 has a lens support part 80 for supporting a lens 14 in a fitting condition. The lens support part 80 has a non-contact region 70 formed of at least a lens tube 12 in which the lens tube 12 and the lens 14 are not in contact with each other, and a positioning and supporting region 72 in which the lens 14 is supposed with respect to the lens tube 12 and positioned concentrically with an optical axis O. The thickness of the positioning and supporting region 72 along the radial direction is set to be thinner than that of the non-contact region 70.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention particularly relates to a lens unit and a camera module that constitute an in-vehicle camera mounted on a vehicle such as an automobile.

Background Art

[0002] In recent years, in-vehicle cameras have been mounted on automobiles to support parking or prevent collisions by image recognition, and attempts have also been made to apply them to autonomous driving. In addition, such a camera module such as an in-vehicle camera generally includes a lens unit having a lens group in which a plurality of lenses are arranged along an optical axis, a lens barrel (barrel) that houses and holds the lens group, and a diaphragm member disposed between at least one pair of lenses in the lens group (see, for example, Patent Document 1).

[0003] In a lens unit, generally, as shown in FIG. 9, a plurality of lenses 101, 102, 103, 104, 105 that constitute a lens group L are incorporated into an inner accommodation space S of a lens barrel 123 so as to be stacked in order from the image side (the lower side in FIG. 9) toward the object side (the upper side in FIG. 9). In this case, in order to prevent the lenses from shifting due to vibration, shock, etc., and resulting in deterioration of resolution performance or deviation of the optical axis, generally, these lenses 101, 102, 103, 104, 105 are directly fitted (or lightly press-fitted) to the inner surface of the lens barrel 123 using the inner surface shape of the lens barrel 123.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, in a state where the lens is directly brought into contact with and fitted into the lens barrel within the lens barrel like this, if there is a difference in the linear expansion coefficient (thermal expansion rate) between the lens barrel and the lens, especially in a high-temperature environment, the lens inside the lens barrel may receive a compressive stress from the lens barrel due to the thermal expansion of the lens, and the surface shape of the lens may be deformed.

[0006] Therefore, in order to suppress such deformation of the lens, it is conceivable to provide a gap between the lens and the lens barrel. However, in that case, the lens may rattle, resulting in deterioration of the resolution performance and deviation of the optical axis, leading to deterioration of the optical performance.

[0007] The present invention has been made in view of the above circumstances, and an object thereof is to provide a lens unit and a camera module that can suppress the compressive stress received by the lens from the lens barrel due to its thermal expansion, accurately center and position the lens within the lens barrel, and regulate the eccentricity of the lens with respect to the optical axis.

Means for Solving the Problems

[0008] In order to solve the above problems, the present invention provides a lens unit including a cylindrical lens barrel that forms an inner accommodation space for accommodating and holding a lens, and a lens group incorporated in the inner accommodation space of the lens barrel, in which a plurality of lenses are arranged along the optical axis, having a lens support portion that supports the lens in a fitted state, the lens support portion is at least formed by the lens barrel, and has a non-contact region where the lens barrel and the lens do not contact each other, and a positioning support region that supports the lens with respect to the lens barrel and positions it concentrically with the optical axis, the positioning support region is characterized in that the thickness along the radial direction is set thinner than that of the non-contact region.

[0009] According to the above configuration of the present invention, the lens support portion that supports the lens in a fitted state has a non-contact region where the lens barrel and the lens do not contact each other, and a positioning support region that supports the lens with respect to the lens barrel and positions it concentrically with the optical axis. Moreover, the thickness along the radial direction of the positioning support region is set to be thinner than that of the non-contact region. In other words, while ensuring a non-contact region where the lens does not contact the lens barrel, in the positioning support region where the lens can directly or indirectly receive compressive stress from the lens barrel during thermal expansion of the lens, the thickness of the lens support portion is set to be thin. Therefore, the thermal expansion of the lens can be effectively released not only in the non-contact region but also in the positioning support region, thereby relaxing the compressive stress acting on the lens and suppressing the deformation of the lens surface shape associated with the compressive stress. Further, although the lens support portion has a non-contact region where the lens barrel and the lens do not contact each other, since the lens can be reliably supported with respect to the lens barrel by the positioning support region and positioned concentrically with the optical axis, there is no risk that the lens will rattle, resulting in deterioration of resolution performance, deviation of the optical axis, and deterioration of optical performance.

[0010] Further, in the above configuration of the present invention, the lens support portion may be formed by an annular insertion member that is inserted between the lens barrel and the outer peripheral side surface of the lens and the inner surface of the lens barrel to position the lens concentrically with the optical axis without contacting the lens barrel. In that case, the insertion member may have a lens fitting portion that fits with the lens without contacting the lens barrel to form a positioning support region, and a lens barrel fitting portion that fits with the lens barrel without contacting the lens to form a non-contact region together with the lens barrel.

[0011] In this way, by inserting an annular insertion member having a lens fitting portion that fits with the lens without contacting the lens barrel and a lens barrel fitting portion that fits with the lens barrel without contacting the lens between the outer peripheral side surface of the lens and the inner surface of the lens barrel, and positioning the lens concentrically with the optical axis without contacting the lens barrel by this insertion member, that is, by not directly contacting and fitting the lens with the lens barrel over the entire circumference within the lens barrel, even if there is a difference in their linear expansion coefficients (thermal expansion rates) between the lens barrel and the lens, the lens will not be affected by the lens barrel accordingly. That is, for example, in a high-temperature environment, even if the lens inside the lens barrel thermally expands, the lens will not receive compressive stress from the lens barrel. Therefore, it is possible to regulate the eccentricity of the lens and suppress the deformation of the lens. Also, since the insertion member is configured to fit with both the lens and the lens barrel, a gap that allows the lens to move is not formed between the lens barrel and the lens. Therefore, it is possible to avoid a situation where the lens rattles, resulting in deterioration of resolution performance, deviation of the optical axis, and deterioration of optical performance.

[0012] In the above configuration, it is preferable that the insertion member has a linear expansion coefficient (thermal expansion rate) equivalent to that of the lens it supports. According to this, it is possible to prevent the lens from receiving compressive stress from the insertion member during its expansion as it fits with the insertion member. Also, the insertion member is preferably formed of a material that can absorb the expansion of the lens, for example, a material having a lower flexural modulus at room temperature than the lens material. Furthermore, the insertion member may be incorporated into the lens barrel, for example, in a state of being fitted around the outer periphery of the lens. This particularly enables smooth incorporation of the lens into the lens barrel via the insertion member, especially in an incorporated configuration where a diaphragm is inserted between the lenses.

[0013] Further, in the above configuration of the present invention, in a cross-section orthogonal to the optical axis, the lens fitting portion of the insertion member may be in point contact with the lens, and the lens barrel fitting portion of the insertion member may be in line contact with the lens barrel. According to this, while minimizing the stress received by the lens from the insertion member, the support of the lens by the lens barrel via the insertion member can be performed reliably and stably. However, both the lens fitting portion and the lens barrel fitting portion may be in line contact or may be in point contact.

[0014] Further, in the above configuration of the present invention, the insertion member may alternately have a lens fitting portion and a lens barrel fitting portion along its circumferential direction. According to this, the supporting force of the lens by the insertion member (lens support stability), as well as the fitting force (stress) received by the lens barrel and the lens from the insertion member, can be evenly dispersed in the circumferential direction, and a mechanically preferable structural form of the lens unit can be realized. Of course, it is not always necessary for the lens fitting portion and the lens barrel fitting portion to be alternately arranged.

[0015] Further, in the above configuration of the present invention, the lenses adjacent to each other in the optical axis direction may have the same circumferential positions of the lens fitting portion and the lens barrel fitting portion of the insertion member, or may have different circumferential positions from each other. If the circumferential positions of the lens fitting portion and the lens barrel fitting portion of the insertion member are different from each other among the lenses adjacent to each other in the optical axis direction, the dispersion of the stress along the optical axis direction can be achieved, and a mechanically preferable structural form of the lens unit can be realized.

[0016] Note that in the above configuration, the materials of the lens barrel and the lens, the form of incorporating the lens, the inner surface shape of the lens barrel, etc. can be arbitrarily set. For example, the inner surface of the lens barrel for incorporating and supporting the lens may have a circular cross-section or may have a polygonal cross-section. Regardless of the shape of the cross-section, the insertion member having the above configuration can be effectively inserted between the lens and the lens barrel.

[0017] Further, a camera module according to the present invention is characterized by including the lens unit. According to such a configuration, the effects of the lens unit described above can be obtained in the camera module.

Advantages of the Invention

[0018] According to the present invention, it is possible to provide a lens unit and a camera module that can accurately center and position the lens within the lens barrel while suppressing the compressive stress received by the lens from the lens barrel due to its thermal expansion, and can regulate the eccentricity of the lens with respect to the optical axis.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Modes for Carrying Out the Invention

[0020] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the lens unit of the present embodiment described below is particularly for a camera module such as an in-vehicle camera. For example, it is fixedly installed on the outer surface side of an automobile, and the wiring is drawn into the automobile and connected to a display or other devices. Also, hatching is omitted for the lenses in FIGS. 1 to 9.

[0021] FIG. 1 shows a lens unit 11 according to a first embodiment of the present invention. As shown in the figure, the lens unit 11 of the present embodiment includes, for example, a cylindrical lens barrel (barrel) 12 made of resin (which may be made of metal), and a plurality of lenses arranged in the stepped inner accommodation space S of the lens barrel 12. For example, from the object side, there are five lenses including a first lens 13, a second lens 14, a third lens 15, a fourth lens 16, and a fifth lens 17, and two aperture members 22a and 22b. In the present embodiment, the aperture members 22a and 22b are inserted between the second lens 14 and the third lens 15, and between the third lens 15 and the fourth lens 16. They are an "aperture stop" that limits the amount of transmitted light and determines the F-value, which is an indicator of brightness, or a "light-shielding stop" that shields light rays that cause ghosts or light rays that cause aberrations. An in-vehicle camera equipped with such a lens unit 11 includes the lens unit 11, a substrate having an image sensor (not shown), and an installation member (not shown) for installing the substrate on a vehicle such as an automobile.

[0022] A plurality of lenses 13, 14, 15, 16, 17 incorporated and accommodated in the inner accommodation space S of the lens barrel 12 are stacked and arranged with their respective optical axes aligned, and are arranged in a state where each lens 13, 14, 15, 16, 17 is arranged along one optical axis O, constituting a group of lens groups L used for imaging. In this case, the first lens 13 located on the object side of the lens group L is a spherical glass lens having a convex surface on the object side and a concave surface on the image side, and the other lenses 14, 15, 16, 17 are resin lenses, but are not limited thereto (for example, the first lens 13 may be a resin lens). Further, an antireflection film, a hydrophilic film, a water-repellent film, etc. are provided on the surfaces of these lenses 13, 14, 15, 16, 17 as necessary.

[0023] In addition, in the present embodiment, two fourth and fifth lenses 16, 17 located on the image side constitute a cemented lens (bonded lens) 40. The fourth and fifth lenses 16, 17 constituting such a cemented lens 40 are assembled by fitting the annular convex portion 16a on the surface facing the image side of the fourth lens 16 located on the object side with the corresponding annular concave portion 17b on the surface facing the object side of the fifth lens 17 located on the image side as shown in the figure, and are integrally fixed by an adhesive or the like.

[0024] In addition, in the present embodiment, an O-ring 26 as a seal member is inserted between the first lens 13 located on the object side and the lens barrel 12 to prevent water and dust from entering the lens group L inside the lens barrel 12. In this case, a stepped reduced-diameter portion 13d with a smaller diameter in the image-side portion of the lens 13 is provided on the outer peripheral side surface 13c of the first lens 13, and the O-ring 26 is mounted on this reduced-diameter portion 13d, and the O-ring 26 is compressed in the radial direction between the outer peripheral side surface 13c of the first lens 13 and the inner peripheral surface of the lens barrel 12, so that the object-side end portion of the lens barrel 12 is in a sealed state.

[0025] Inside the lens barrel 12, a cylindrical inner wall 12b is provided on the object side. A groove is formed between this inner wall 12b and the outer wall 12a, and an annular body 27 is provided in the groove, and an O-ring 26 is in close contact with this annular body 27. The reason for forming a groove between the inner wall 12b and the outer wall 12a is that when there is no groove and the inner wall 12b and the outer wall 12a are integrated, the wall thickness becomes thick, so when molding and cooling the resin lens barrel 12, large sink marks are generated and the dimensional accuracy is distorted. The annular body 27 is made of a substance having relatively soft elasticity, for example, Teflon is used. The annular body 27 has a function of supporting the O-ring 26 in the optical axis direction. Since the annular body 27 is a separate member from the lens barrel 12, it can be changed to an annular body 27 with different heights according to the size of the O-ring 26, ensuring that the O-ring 26 seals with an appropriate elastic force.

[0026] Also, with the lens group L incorporated and held in the inner accommodation space S of the lens barrel 12, the caulking portion 23 at the object-side end (the upper end portion in FIG. 1) of the lens barrel 12 is caulked radially inward, so that the first lens 13 located on the most object side of the lens group L is fixed to the object-side end of the lens barrel 12 by this caulking portion 23. Note that the fixing of the first lens 13 is not limited to the caulking portion 23, and may be performed by a fixing portion attached to the object-side end of the lens barrel 12 after the lenses 13, 14, 15, 16, 17 are accommodated in the lens barrel 12.

[0027] Also, an inner flange portion 24 having an opening smaller in diameter than the fifth lens 17 is provided at the image-side end (the lower end portion in FIG. 1) of the lens barrel 12. By this inner flange portion 24 and the caulking portion 23, a plurality of lenses 13, 14, 15, 16, 17 and diaphragm members 22a, 22b constituting the lens group L in the lens barrel 12 are held and fixed in the optical axis direction.

[0028] In addition, the lens unit 11 of the present embodiment has a lens support portion 80 that supports, in a fitted state, at least one lens constituting the lens group L, particularly, in the present embodiment, all lenses 14, 15, 17 except for one of the first lens 13 and the cemented lens, here the fourth lens 16. Specifically, in the present embodiment, as shown in FIGS. 1 and 2, the lens support portion 80 is formed by a lens barrel 12 having a circular cross section and an annular insertion member 30 inserted between the outer peripheral side surfaces 14a (15a, 17a) of the lenses 14, 15, 17 and the inner surface 12c of the lens barrel 12.

[0029] Further, the lens support portion 80 of the present embodiment formed by the lens barrel 12 and the insertion member 30 has a non-contact region 70 where the lens barrel 12 and the lenses 14, 15, 17 do not contact each other, particularly, in the present embodiment, the lens barrel 12, the insertion member 30, and the lenses 14, 15, 17 do not contact each other, and a positioning support region 72 that supports the lenses 14, 15, 17 (by the insertion member 30 in the present embodiment) with respect to the lens barrel 12 and positions them concentrically with the optical axis O.

[0030] As clearly shown in FIG. 2, the insertion member 30 that forms the lens support portion 80 together with the lens barrel 12 is fitted with the lens 14 (15, 17) without contacting the lens barrel 12 to position it concentrically with the optical axis O, and has a lens fitting portion 30a that forms a positioning support region 72 by fitting with the lens 14 (15, 17) without contacting the lens barrel 12, and a lens barrel fitting portion 30b that forms a non-contact region 70 together with the lens barrel 12 by fitting with the lens barrel 12 without contacting the lens 14 (15, 17). These lens fitting portion 30a and lens barrel fitting portion 30b may be provided at least one or more in at least a part of the circumferential direction of the annular insertion member 30. Particularly in the present embodiment, the insertion member 30 has the lens fitting portion 30a and the lens barrel fitting portion 30b continuously alternating along its circumferential direction (therefore, the non-contact region 70 and the positioning support region 72 are provided continuously alternating along the circumferential direction). Specifically, three linear lens fitting portions 30a and three substantially arc-shaped lens barrel fitting portions 30b are positioned adjacent to each other. In this case, as can be seen from FIG. 2, in a cross section orthogonal to the optical axis O, the lens fitting portion 30a of the insertion member 30 makes point contact with the lens 14 (15, 17) (in FIG. 2, the contact point is indicated by C1), and the lens barrel fitting portion 30b makes line contact with the lens barrel 12 (in FIG. 2, the line contact portion is indicated by C2). In addition, as shown enlarged in FIG. 3, the insertion member 30 is supported by a step portion 12d formed on the inner surface 12c of the lens barrel 12 at its lens barrel fitting portion 30b, and further movement in the optical axis direction toward the image side is blocked.

[0031] Also, as shown in FIG. 2, in the present embodiment, the thickness T2 along the radial direction of the positioning support region 72 formed by the insertion member 30 (in the present embodiment, the thickness T2 of the lens fitting portion 30a) is set to be thinner than the thickness T1 along the radial direction of the non-contact region 70 formed by the lens barrel 12 and the insertion member 30 (in the present embodiment, the sum of the thickness of the lens barrel 12 and the thickness of the lens barrel fitting portion 30b).

[0032] Also, as can be seen from FIG. 1, in the present embodiment, between lenses adjacent to each other in the optical axis O direction (adjacent second lens 14 and third lens 15; adjacent third lens 15 and cemented lens 40 (here, the fifth lens 17)), the circumferential positions of the lens fitting portion 30a and the lens barrel fitting portion 30b of the insertion member 30 are the same as each other. That is, when viewed from the direction of the optical axis O, the circumferential positions of the lens fitting portion 30a and the lens barrel fitting portion 30b of the insertion member 30 of each of the lenses 14, 15, 17 completely coincide.

[0033] Incidentally, the insertion member 30 preferably has the same linear expansion coefficient (thermal expansion rate) as the lens 14 (15, 17) it supports. According to this, it is possible to prevent the lens 14 (15, 17) from receiving compressive stress from the insertion member 30 during its expansion as it fits with the insertion member 30. Further, the insertion member 30 may be formed of a material capable of absorbing the expansion of the lens 14 (15, 17). Examples of the material forming the insertion member 30 include Reney and Zylon (trade names), which are nylon-based materials. Also, in the case of a resin lens barrel, it is preferable to use the same material for the insertion member 30 in order to match the linear expansion rate with the lens barrel. Further, the insertion member 30 may be incorporated into the lens barrel 12, for example, in a state of being fitted around the outer periphery of the lens 14 (15, 17).

[0034] FIG. 4 is a schematic cross-sectional view of the camera module 300 of the present embodiment having the lens unit 11 configured as described above. As shown in the figure, this camera module 300 is configured to include the lens unit 11 of FIG. 1 to which the filter 100 is attached.

[0035] The camera module 300 includes an upper case (camera case) 301 which is an exterior component, and a mount (pedestal) 302 that holds the lens unit 11. The camera module 300 also includes a seal member 303 and a package sensor (imaging element) 304.

[0036] The upper case 301 is a member that engages with a flange portion 25 provided in a flange shape on the outer peripheral surface 12a of the lens barrel 12 and exposes the object-side end of the lens unit 11 while covering the other portions. The mount 302 is disposed inside the upper case 301 and has a female screw 302a that engages with the male screw 11a of the lens unit 11. The seal member 303 is a member inserted between the inner surface of the upper case 301 and the outer peripheral surface 12a of the lens barrel 12 of the lens unit 11 and is a member for maintaining the airtightness inside the upper case 301.

[0037] The package sensor 304 is disposed inside the mount 302 and is positioned at a location where the image of an object formed by the lens unit 11 is received. Further, the package sensor 304 has a transparent cover on the outside and includes a CCD, a CMOS, etc. inside, and converts the light that is condensed and reaches through the lens unit 11 into an electrical signal. The converted electrical signal is converted into analog data or digital data that are components of the image data photographed by the camera.

[0038] As described above, according to the present embodiment, the lens support portion 80 that supports the lens 14 (15, 17) in a fitted state has a non-contact region 70 where the lens barrel 12 and the lens 14 (15, 17) do not contact each other, and a positioning support region 72 that supports the lens 14 (15, 17) with respect to the lens barrel 12 and positions it concentrically with the optical axis O. Since the thickness T2 along the radial direction of the positioning support region 72 is set to be thinner than the thickness T1 along the radial direction of the non-contact region 70, in other words, while ensuring the non-contact region 70 where the lens 14 (15, 17) does not contact the lens barrel 12, in the positioning support region 72 where the lens 14 (15, 17) can indirectly receive compressive stress from the lens barrel 12 during thermal expansion of the lens 14 (15, 17), the thickness of the lens support portion 80 is set to be thin. Therefore, the thermal expansion of the lens 14 (15, 17) can be effectively released not only in the non-contact region 70 but also in the positioning support region 72, thereby relaxing the compressive stress acting on the lens 14 (15, 17) and suppressing the deformation of the surface shape of the lens 14 (15, 17) associated with the compressive stress. Further, the lens support portion 80 can reliably support the lens 14 (15, 17) with respect to the lens barrel 12 by the positioning support region 72 and position it concentrically with the optical axis O while having the non-contact region 70 where the lens barrel 12 and the lens 14 (15, 17) do not contact each other. Therefore, there is no possibility that the lens 14 (15, 17) rattles, resulting in deterioration of resolution performance or optical axis deviation, leading to deterioration of optical performance.

[0039] In particular, in the present embodiment, an annular insertion member 30 having a lens fitting portion 30a that fits with the lens 14 (15, 17) to form a positioning support region 72 without contacting the lens barrel 12, and a lens barrel fitting portion 30b that fits with the lens barrel 12 without contacting the lens 14 (15, 17) to form a non-contact region 70 together with the lens barrel 12, is inserted between the outer peripheral side surface 14a (15a, 17a) of the lens 14 (15, 17) and the inner surface 12c of the lens barrel 12 as a member that forms a lens support portion together with the lens barrel 12. Since the lens 14 (15, 17) is positioned concentrically with the optical axis O without contacting the lens barrel 12 by this insertion member 30, that is, since the lens 14 (15, 17) is not directly contact-fitted with the lens barrel 12 over the entire circumference within the lens barrel 12, even if there is a difference in the linear expansion coefficient (thermal expansion rate) between the lens barrel 12 and the lens 14 (15, 17), the lens 14 (15, 17) will not be affected by the lens barrel 12 accordingly. That is, for example, in a high-temperature environment, even if the lens 14 (15, 17) inside the lens barrel 12 thermally expands, the lens 14 (15, 17) will not receive compressive stress from the lens barrel 12. Therefore, eccentricity of the lens 14 (15, 17) can be regulated, and deformation of the lens 14 (15, 17) can also be suppressed. Further, since the insertion member 30 is adapted to fit with both the lens 14 (15, 17) and the lens barrel 12, a gap that allows the lens 14 (15, 17) to move is not formed between the lens barrel 12 and the lens 14 (15, 17). Therefore, a situation where the lens 14 (15, 17) rattles, resulting in deterioration of resolution performance, optical axis deviation, and deterioration of optical performance, can be avoided.

[0040] Moreover, according to the present embodiment, since the insertion member 30 alternately has the lens fitting portion 30a and the lens barrel fitting portion 30b along its circumferential direction, the supporting force of the lens 14 (15, 17) by the insertion member 30 (the supporting stability of the lens 14 (15, 17)), and the fitting force (stress) received by the lens barrel 12 and the lens 14 (15, 17) from the insertion member 30 can be evenly dispersed in the circumferential direction, and a mechanically preferable structural form of the lens unit 11 can be realized.

[0041] Further, according to the present embodiment, in a cross section orthogonal to the optical axis O, the lens fitting portion 30a of the insertion member 30 is in point contact with the lens 14 (15, 17), and the lens barrel fitting portion 30b of the insertion member 30 is in line contact with the lens barrel 12. Therefore, while minimizing the stress received by the lens 14 (15, 17) from the insertion member 30, the lens 14 (15, 17) can be reliably and stably supported by the lens barrel 12 via the insertion member 30.

[0042] FIG. 5 shows a second embodiment of the present invention. As shown in the figure, in the lens unit 11A according to the present embodiment, between the lenses adjacent to each other in the optical axis O direction (the adjacent second lens 14 and third lens 15; the adjacent third lens 15 and joining lens 40 (here, the fifth lens 17)), the circumferential positions of the lens fitting portion 30a and the lens barrel fitting portion 30b of the insertion member 30 are different from each other. This is the only difference from the first embodiment in this regard. That is, when viewed from the direction of the optical axis O, the circumferential positions of the lens fitting portion 30a and the lens barrel fitting portion 30b of the insertion member 30 of each of the lenses 14, 15, 17 do not coincide. For example, at a predetermined circumferential position, in the insertion member 30 of the second lens 14, the lens barrel fitting portion 30b is located, while in the insertion member 30 of the third lens 15, the lens fitting portion 30a is located. Also, at a predetermined circumferential position, in the insertion member 30 of the third lens 15, the lens barrel fitting portion 30b is located, while in the insertion member 30 of the fifth lens 17, the lens fitting portion 30a is located.

[0043] Thus, if the circumferential positions of the lens fitting portion 30a and the lens barrel fitting portion 30b of the insertion member 30 are different from each other between the lenses adjacent to each other in the optical axis O direction, the dispersion of the stress along the optical axis O direction can be achieved, and a mechanically preferable structural form of the lens unit can be realized.

[0044] FIG. 6 shows a third embodiment of the present invention. As shown in the figure, in the lens unit 11B according to the present embodiment, the insertion member 30A has a hexagonal shape in which three linear lens fitting portions 30a that are in point contact with the lenses 14 (15, 17) and three linear lens barrel fitting portions 30b that are in line contact with the lens barrel 12A are alternately and continuously adjacent to each other along the circumferential direction so as to be inserted between the lens barrel 12A having an inner surface 12c with a hexagonal cross section and the lenses 14 (15, 17). It is different from the first and second embodiments only in this respect. Even in such an insertion member 30A, the same operational effects as those of the above-described embodiments can be achieved. Note that the shape of the inner surface 12c of the lens barrel 12A does not have to be hexagonal, and may be a quadrilateral, a pentagon, an octagon, or the like, and the insertion member 30A can have a polygonal shape corresponding thereto. In this case, in order to reduce the size of the lens barrel 12A and stably support the lenses, etc., it is preferable that the lens fitting portion 30a and the inner surface 12c of the lens barrel 12A facing the lens fitting portion 30a are parallel to each other.

[0045] Figures 7 and 8 show a fourth embodiment of the present invention. As shown in the figures, in the lens unit 11C according to the present embodiment, the lens support portion 80A that supports the lenses 14, 15, and 17 in a fitted state is formed only by the lens barrel 12B having a circular cross-section without the above-described insertion member 30 (30A). Specifically, the lens support portion 80A of the present embodiment has a non-contact region 70 where the lens barrel 12B and the lenses 14, 15, and 17 do not contact each other, and a positioning support region 72 that supports the lenses 14, 15, and 17 with respect to the lens barrel 12B (in the present embodiment, the lenses 14, 15, and 17 are directly supported by the lens barrel 12B (therefore, the lenses 14, 15, and 17 and the lens barrel 12B are in direct contact)) and is positioned concentrically with the optical axis O. The positioning support region 72 is formed by a thin-walled portion 12e of the lens barrel 12B that is substantially linear and in point contact with the lenses 14, 15, and 17, for example, in a cross-section orthogonal to the optical axis O. In this case, the thin-walled portion 12e is formed by providing a recessed groove 90 radially inward on the outer peripheral surface portion of the lens barrel 12B that forms the positioning support region 72 of the lens support portion 80A. That is, in the present embodiment, the thickness T2 along the radial direction of the portion of the lens barrel 12B that forms the positioning support region 72 (that is, the thin-walled portion 12e) is thinner than the thickness T1 along the radial direction of the portion of the lens barrel 12B that forms the non-contact region 70. Further, if the circumferential positions of the thin-walled portions 12e of the respective lenses 14, 15, and 17 are aligned (the thin-walled portions 12e are offset only in one direction), deformation of the lens barrel 12B may occur. Therefore, in the present embodiment, the formation positions of the thin-walled portions 12e are staggered for each of the lenses 14, 15, and 17. That is, the lenses adjacent to each other in the direction of the optical axis O (the adjacent second lens 14 and third lens 15; the adjacent third lens 15 and joined lens 40 (here, the fifth lens 17)) have different circumferential positions of the thin-walled portions 12e (positioning support region 72) (therefore, the circumferential positions of the non-contact region 70 are also different). For example, at a predetermined circumferential position, the thin-walled portion 12e (positioning support region 72) is positioned in the second lens 14, while the non-contact region 70 is positioned in the third lens 15.Also, at a predetermined circumferential position, the thin portion 12e (positioning and supporting region 72) is positioned in the third lens 15, while the non-contact region 70 is positioned in the fifth lens 17.

[0046] Also, in the present embodiment, the lens support portion 80A is formed such that the non-contact region 70 and the positioning and supporting region 72 are alternately and continuously provided along the circumferential direction. Further, the inner surface 12c of the lens barrel 12B forming the non-contact region 70 and the positioning and supporting region 72 are both linear in a cross-section orthogonal to the optical axis O. Therefore, the lens barrel 12B has an inner surface 12c with a polygonal cross-section (hexagonal in FIG. 8). However, the inner surface 12c of the lens barrel 12B forming the non-contact region 70 and / or the positioning and supporting region 72 may be arc-shaped. In the present embodiment, the lens support portions 80A of the lenses adjacent to each other in the optical axis direction may have the same circumferential positions of the non-contact region 70 and the positioning and supporting region 72, or may be different from each other.

[0047] As described above, also in the present embodiment, similar to the above-described embodiment, the lens support portion 80A that supports the lens 14 (15, 17) in a fitting state has a non-contact region 70 where the lens barrel 12B and the lens 14 (15, 17) do not contact each other, and a positioning support region 72 that supports the lens 14 (15, 17) with respect to the lens barrel 12B and positions it concentrically with the optical axis O. Since the thickness T2 along the radial direction of the positioning support region 72 is set to be thinner than the thickness T1 along the radial direction of the non-contact region 70, in other words, while ensuring the non-contact region 70 where the lens 14 (15, 17) does not contact the lens barrel 12B, in the positioning support region 72 where the lens 14 (15, 17) can directly receive compressive stress from the lens barrel 12B during thermal expansion of the lens 14 (15, 17), the thickness of the lens support portion 80A is set to be thin. Therefore, the thermal expansion of the lens 14 (15, 17) can be effectively released not only in the non-contact region 70 but also in the positioning support region 72, the compressive stress acting on the lens 14 (15, 17) can be relaxed, and the deformation of the surface shape of the lens 14 (15, 17) due to the compressive stress can be suppressed. Further, the lens support portion 80A can surely support the lens 14 (15, 17) with respect to the lens barrel 12B by the positioning support region 72 and position it concentrically with the optical axis O while having the non-contact region 70 where the lens barrel 12B and the lens 14 (15, 17) do not contact each other. Therefore, there is no possibility that the lens 14 (15, 17) rattles, resulting in deterioration of resolution performance or deviation of the optical axis, leading to deterioration of optical performance.

[0048] Note that the present invention is not limited to the above-described embodiment and can be implemented with various modifications without departing from the gist thereof. For example, in the present invention, the shapes of the lens, the lens barrel, the insertion member, etc. are not limited to the above-described embodiment. Further, in the above-described embodiment, the lens support portion (insertion member) is provided for the second, third, and fifth lenses. However, for example, when the fourth lens and the fifth lens are not the cemented lens 40, the lens support portion may be provided for all the lenses including the first lens and the fourth lens (an insertion member may be interposed between all the lenses and the lens barrel).

Explanation of Reference Numerals

[0049] 11, 11A, 11B, 11C lens unit 12, 12A lens barrel 12c inner surface 13, 14, 15, 16, 17 lenses 14a, 15a, 17a outer peripheral surfaces 30 insertion member 30a lens fitting portion 30b lens barrel fitting portion 70 non-contact region 72 positioning and supporting region 80, 80A lens support 300 camera module O optical axis S inner accommodation space

Claims

1. A lens unit comprising a cylindrical lens barrel that forms an inner accommodation space for accommodating and holding a lens, and a lens group incorporated in the inner accommodation space of the lens barrel, wherein a plurality of lenses are arranged along an optical axis, the lens unit further comprising an annular insertion member that is inserted between an outer peripheral side surface of the lens and an inner surface of the lens barrel to position the lens concentrically with the optical axis without contacting the lens barrel, the insertion member having a lens fitting portion that fits with the lens without contacting the lens barrel, and a lens barrel fitting portion that fits with the lens barrel without contacting the lens barrel, a thickness along a radial direction of the lens fitting portion being thinner than a sum of a thickness along a radial direction of the lens barrel fitting portion and a thickness along a radial direction of the lens barrel that fits with the lens barrel fitting portion, in a cross section orthogonal to the optical axis, the lens barrel fitting portion is in line contact with an inner surface of the lens barrel over its entire length, and the lens fitting portion extends linearly between the lens barrel fitting portions while being in point contact with the lens so as to connect the lens barrel fitting portions to each other. A lens unit characterized by this.

2. The lens unit according to claim 1, wherein the insertion member alternately has the lens fitting portion and the lens barrel fitting portion along a circumferential direction thereof.

3. The lens unit according to claim 2, wherein lens barrel fitting portions and lens fitting portions of the insertion member have the same circumferential positions for lenses adjacent to each other in an optical axis direction.

4. The lens unit according to claim 2, wherein lens barrel fitting portions and lens fitting portions of the insertion member have different circumferential positions for lenses adjacent to each other in an optical axis direction.

5. A lens unit comprising a cylindrical lens barrel that forms an inner accommodation space for accommodating and holding a lens, and a lens group incorporated in the inner accommodation space of the lens barrel, wherein a plurality of lenses are arranged along an optical axis, the lens barrel having a non-contact region that does not contact the lens, and a positioning support region that directly supports the lens and positions it concentrically with the optical axis, the positioning support region being set to have a thickness along a radial direction that is thinner than that of the non-contact region. All of the positioning support regions are in a cross-section orthogonal to the optical axis, in contact with the lens in a point contact manner so as to connect the non-contact regions, extending linearly between the non-contact regions, and having a linear outer peripheral surface connecting the arc-shaped outer peripheral surfaces of the non-contact regions and a linear inner peripheral surface connecting the linear inner peripheral surfaces of the non-contact regions. A lens unit characterized by this.

6. The lens barrel has an inner surface with a circular cross-section. The lens unit according to any one of claims 1 to 4, characterized by this.

7. The lens barrel has an inner surface with a polygonal cross-section. The lens unit according to any one of claims 1 to 5, characterized by this.

8. A camera module characterized by including the lens unit according to any one of claims 1 to 7.

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