Lens unit

Abstract

To provide a lens unit capable of easily aligning a lens.SOLUTION: A lens unit 1 has: a plurality of lenses including a fifth lens 7; a first lens barrel member 20 housing the plurality of lens inside; a diaphragm provided between any of the plurality of lenses; and a holder 70 holding the fifth lens 7 from radially outside and held by the first lens barrel member 20. The holder 70 is provided with: a first holding member 71 held by the first lens barrel member 20; and a second holding member 72 which holds the fifth lens 7, does not contact an inner peripheral surface 220 of the first lens barrel member 20, and is rotatable around an optical axis X with respect to the first holding member 71. The first lens barrel member 20 is provided with a plurality of openings 29 provided at a position overlapping at least a part of the second holding member 72 when seen from the direction orthogonal to the optical axis X. The second holding member 72 is rotated with respect to the optical axis X, so that the fifth lens 7 is aligned.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to a lens unit capable of performing lens centering.

[0002] A lens unit used in an imaging device mounted on an automobile or a surveillance camera is described in Patent Document 1. The lens unit in the document has a plurality of lenses arranged in the optical axis direction, a holder that holds the plurality of lenses inside, and an aperture provided between any of the plurality of lenses. Of the plurality of lenses, an object-side lens adjacent to the aperture on the object side, and one of an image-side lens adjacent to the aperture on the image side are centering lenses whose positions are adjusted in a direction perpendicular to the optical axis. The holder includes a first holder that holds the centering lens inside, and a second holder that holds the first holder inside. The second holder has centering openings formed at a plurality of locations in the circumferential direction at positions that overlap with at least a part of the first holder when viewed from a direction perpendicular to the optical axis direction. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2015-175918 A Summary of the Invention [Problem to be solved by the invention]

[0004] When assembling the lens unit, the centering lens is aligned with respect to the optical axis by moving the centering lens in the X direction and the Y direction, which are perpendicular to the optical axis. This adjusts the optical performance of the lens unit. However, since it is necessary to move the lens in two axial directions that are perpendicular to the optical axis and perpendicular to each other, there is a problem that centering the centering lens is difficult.

[0005] In view of the above problems, an object of the present invention is to provide a lens unit that allows easy centering of the lens. [Means for solving the problem]

[0006] In order to solve the above problem, the lens unit of the present invention comprises a plurality of lenses arranged in an optical axis direction along an optical axis, the plurality of lenses including a centering lens, a first barrel member that houses the plurality of lenses inside, an aperture provided between any of the plurality of lenses, and a holder that holds the centering lens from the radial outside and is held by the first barrel member, wherein the holder comprises a first holding member held by the first barrel member, and a second holding member that holds the centering lens, is not in contact with the inner surface of the first barrel member, and is rotatable around the optical axis relative to the first holding member, wherein the first barrel member has a plurality of openings provided at a position that overlaps with at least a portion of the second holding member when viewed from a direction perpendicular to the optical axis, and the centering lens is centered by rotating the second holding member about the optical axis.

[0007] According to the present invention, the second holding member that holds the centering lens can be rotated from the outside of the first barrel member relative to the first holding member. Here, the center of the centering lens held by the second holding member may be eccentric with respect to the optical axis. In this case, when the second holding member is rotated around the optical axis, the amount of deviation of the centering lens changes depending on the angular position of the second holding member. Therefore, by rotating the second holding member, centering can be performed so that the amount of deviation of the centering lens is reduced. Therefore, compared to the case where the centering lens is centered by moving the centering lens in two axial directions that are perpendicular to the optical axis and perpendicular to each other, In the lens unit of the present invention, the centering of the centering lens can be easily performed.

[0008] In the present invention, it is preferable that the centering lens is a lens among the plurality of lenses that is adjacent to either one of the object side of the aperture and the image side of the aperture. In this way, it is possible to center the lens that has the greatest effect on the optical performance of the lens unit.

[0009] In the present invention, it is preferable that the holder includes a guide portion that supports the second holding member rotatably about the optical axis relative to the first holding member, which makes it easy to rotate the second holding member relative to the first holding member.

[0010] In the present invention, the guide portion comprises a first surface portion provided on one side of the first holding member and the second holding member, facing radially inward, and having an arc-shaped configuration centered on the optical axis, and a second surface portion provided on the other side of the first holding member and the second holding member, facing radially outward, and having an arc-shaped configuration centered on the optical axis, and it is preferable that the first surface portion and the second surface portion face each other in the radial direction.

[0011] In the present invention, it is preferable that the first surface portion is inclined radially outward toward the other side of the first holding member and the second holding member, and the second surface portion is inclined radially inward toward one side of the first holding member and the second holding member. In this way, it is easy to align the centers of the first holding member and the second holding member.

[0012] In the present invention, it is preferable that the holder includes an adjustment unit that moves the second holding member in the optical axis direction relative to the first holding member when the second holding member rotates relative to the first holding member. In this way, it is possible to adjust the position of the centering lens in the optical axis direction while centering the centering lens.

[0013] In the present invention, the adjustment portion may include a female thread portion provided on one side of the first retaining portion and the second retaining portion, and a male thread portion provided on the other side of the first retaining portion and the second retaining portion and screwed into the female thread portion.

[0014] In the present invention, the adjustment portion can include a cam groove provided on one side of the first retaining portion and the second retaining portion and formed spirally in the optical axis direction, and a cam pin provided on the other side of the first retaining portion and the second retaining portion and inserted into the cam groove.

[0015] In the present invention, the second holding member preferably has a recess on its outer circumferential surface. In this way, when an alignment jig is inserted through the opening and the second holding member is rotated, the tip of the jig can be fitted into the recess. This makes it easier to hold the second holding member with the jig.

[0016] In the present invention, it is preferable to have an elastic member provided between any of the lenses of the plurality of lenses. In this way, even if a force in the optical axis direction is applied to the plurality of lenses after the plurality of lenses are assembled into the first barrel member, the force in the optical axis direction applied to the plurality of lenses when the second holding member is rotated is released by compressing the elastic member in the optical axis direction. This makes it easier to rotate the second holding member.

[0017] In the present invention, it is preferable that the elastic member is provided between the lenses having the largest on-axis surface distance among the lenses of the plurality of lenses. In this way, even if the compression amount of the elastic member changes when the second holding member is rotated, the lens unit can be kept in a constant state. The optical performance is less affected.

[0018] In the present invention, the optical system can have an object-side lens arranged on the object side of the plurality of lenses, and a second barrel member that houses the object-side lens inside and holds the first barrel member inside. Effect of the Invention

[0019] According to the present invention, the second holding member that holds the centering lens can be rotated from the outside of the first barrel member relative to the first holding member. As a result, by rotating the second holding member, centering can be performed so that the amount of eccentricity of the centering lens is reduced, so the lens unit of the present invention can easily center the centering lens. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 is an external perspective view of a lens unit according to a first embodiment. [Diagram 2] 2 is a cross-sectional view of the lens unit taken along line AA in FIG. 1. [Diagram 3] FIG. 2 is an exploded perspective view of the lens unit. [Figure 4] FIG. 4 is a perspective view of a first barrel member. [Diagram 5] FIG. 2 is a perspective view of a holder according to the first embodiment. [Figure 6] FIG. 2 is an exploded perspective view of the holder of the first embodiment as viewed from the object side. [Figure 7] FIG. 2 is an exploded perspective view of the holder of the first embodiment as viewed from the image side. [Figure 8] 5A and 5B are diagrams showing the relationship between a first barrel member and a holder in the first embodiment. [Figure 9] FIG. 11 is a perspective view of a holder according to a second embodiment. [Figure 10] FIG. 11 is an exploded perspective view of the holder of the second embodiment as viewed from the object side. [Figure 11] 13 is a diagram showing the relationship between a first barrel member and a holder in the second embodiment. FIG. [Figure 12] FIG. 11 is a perspective view of a holder according to a third embodiment. [Figure 13] FIG. 11 is an exploded perspective view of a holder according to a third embodiment as viewed from the object side. [Figure 14] 13 is a diagram showing the relationship between a first barrel member and a holder in the third embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a lens unit to which the present invention is applied will be described with reference to the drawings.

[0022] Fig. 1 is an external perspective view of a lens unit of embodiment 1. Fig. 2 is a cross-sectional view of the lens unit taken along line AA in Fig. 1. Fig. 3 is an exploded perspective view of the lens unit. The lens unit 1 of this embodiment is used in an imaging device mounted in an automobile or a surveillance camera.

[0023] (Overall composition) As shown in FIG. 1, the lens unit 1 includes a first lens 3 and a lens barrel 2. As shown in FIG. 2, the lens unit 1 includes a lens group 11 including a plurality of lenses held by the lens barrel 2 on the image side X1 of the first lens 3 in the optical axis direction along the optical axis X of the first lens 3. The lens group 11 includes a second lens 4, a third lens 5, a fourth lens 6, a fifth lens 7, and a sixth lens 10 in the optical axis direction from the object side X2 to the image side X1. The sixth lens 10 is a cemented lens in which two lenses are cemented together. Each of the lenses 4 to 10 constituting the lens group 11 has an outer diameter smaller than that of the first lens 3. The lens unit 1 also includes an annular light-shielding sheet 12 disposed between the second lens 4 and the third lens 5, and an annular diaphragm 13 disposed between the fourth lens 6 and the fifth lens 7. The diaphragm 13 is also an aperture diaphragm set to define the brightness of the optical system of the lens unit 1.

[0024] (lens) The first lens 3 is made of resin or glass. As shown in FIG. It is a meniscus lens with a convex shape on the object side X2. The first lens 3 has an annular end face 3a that expands in a direction perpendicular to the optical axis X on the outer periphery of the lens surface on the image side X1. An annular elastic member 15 is disposed on the image side X1 of the end face 3a of the first lens 3. In this embodiment, the elastic member 15 is an O-ring.

[0025] The second lens 4 is made of resin. The second lens 4 includes a lens body 4a having a lens surface, and a flange 4b ​​surrounding the lens body 4a. The second lens 4 is a meniscus lens having a convex shape on the object side X2. An annular protrusion 4c protruding toward the object side X2 is provided on the end face of the flange 4b ​​on the object side X2. The tip of the annular protrusion 4c contacts the end face 3a of the first lens 3.

[0026] 2, the third lens 5 is made of resin. The third lens 5 includes a lens body 5a having a lens surface and a flange 5b surrounding the lens body 5a. The third lens 5 is a meniscus lens having a convex shape on the image side X1.

[0027] 2, an annular elastic member 16 is disposed between the second lens 4 and the third lens 5. The elastic member 16 is an O-ring. The elastic member 16 is compressed in the optical axis direction between the flange portion 4b of the second lens 4 and the flange portion 5b of the third lens 5. In this embodiment, the elastic member 16 is located between the second lens 4 and the third lens 5 via the light-shielding sheet 12. The second lens 4 and the third lens 5 are not in contact with each other, and the second lens 4 and the third lens 5 are positioned in the optical axis direction by the compression of the elastic member 16. Therefore, the axial surface distance between the second lens 4 and the third lens 5 is determined by the compression amount of the elastic member 16. Here, the axial surface distance between the second lens 4 and the third lens 5 is the largest between the lenses.

[0028] The fourth lens 6 is made of resin. As shown in Fig. 2, the fourth lens 6 includes a lens body 6a having a lens surface and a flange 6b surrounding the lens body 6a. The lens body 6a includes a curved surface protruding toward the object side X2 on the object side X2, and a curved surface protruding toward the image side X1 on the image side X1.

[0029] The fifth lens 7 (centering lens) is made of glass. As shown in FIG. 2, the fifth lens 7 has an outer diameter smaller than the second lens 4, the third lens 5, and the fourth lens 6. The fifth lens 7 includes a lens body portion 7a having a lens surface, and a flange portion 7b surrounding the lens body portion 7a. The fifth lens 7 is a biconvex lens. The fifth lens 7 is positioned between the fourth lens 6 and the sixth lens 10 while being held by an annular holder 70. Here, the diaphragm 13 is sandwiched between the fourth lens 6 and the holder 70. That is, the fifth lens 7 is a lens adjacent to the diaphragm 13 on the image side X1.

[0030] The sixth lens 10 includes an object-side lens 8 and an image-side lens 9 located on the image side X1 of the object-side lens 8. Both the object-side lens 8 and the image-side lens 9 are made of resin. The object-side lens 8 includes a lens body 8a having a lens surface and a flange 8b surrounding the lens body 8a. The lens body 8a includes a curved surface on the object side X2 that curves toward the image side X1, and a curved surface on the image side X1 that is recessed toward the object side X2. An annular protrusion 8c protruding toward the object side X2 is provided on the inner peripheral edge of an end face 81 on the object side X2 of the flange 8b. The outer peripheral surface of the annular protrusion 8c includes an inclined surface 82 that inclines toward the object side X2. Here, the end face 81, the inclined surface 82, and the end face 83 of the annular protrusion 8c are embossed. In addition, the end face 81, the inclined surface 82, and the end face 83 of the annular protrusion 8c are coated with black ink.

[0031] The image-side lens 9 includes a lens body 9a having a lens surface and a flange 9b surrounding the lens body 9a. The lens body 9a has a curved surface protruding toward the object side X2. The image-side lens 9 has a curved surface, and at the image side X1, has a curved surface that protrudes toward the image side X1. The image-side lens 9 is cemented to the object-side lens 8 in a state in which the curved surface that protrudes toward the object side X2 is inserted into the curved surface of the object-side lens 8 that is recessed toward the object side X2. The outer diameter of the image-side lens 9 is smaller than the outer diameter of the object-side lens 8. Therefore, as shown in FIG. 2, when viewed from the image side X1, the flange portion 8b of the object-side lens 8 has a portion that protrudes outward from the image-side lens 9 to the outer periphery.

[0032] Here, the outer diameter of the third lens 5, the outer diameter of the fourth lens 6, the outer diameter of the holder 70 that holds the fifth lens 7, and the outer diameter of the sixth lens 10 are slightly shorter in that order.

[0033] (Telescope tube) 2 and 3, the lens barrel 2 includes a first lens barrel member 20 that holds the lens group 11, and a second lens barrel member 30 that holds the first lens 3. The first lens barrel member 20 is housed on the inner peripheral side of the second lens barrel member 30.

[0034] The first barrel member 20 is made of a non-crystalline resin having light absorbing properties. The second barrel member 30 is made of a crystalline resin having light absorbing properties. In this embodiment, the first barrel member 20 is made of polycarbonate. The second barrel member 30 is made of a polyamide-based resin.

[0035] (Second barrel member) As shown in Figures 2 and 3, the second barrel member 30 includes a first tube portion 31 that holds the first lens 3 from the outer circumferential side, a second tube portion 32 that holds the first barrel member 20 from the outer circumferential side, an annular step portion 33 at the object side X2 end of the second tube portion 32, and an annular step portion 34 protruding from the inner circumferential side from the image side X1 end of the second tube portion 32.

[0036] The first tube portion 31 is provided with an abutment portion 35 at the end portion on the object side X2 that bends inward and abuts against the first lens 3 from the object side X2. An inner peripheral surface 36 on the object side X2 of the second tube portion 32 is provided with protrusions 360 that protrude radially inward at multiple locations in the circumferential direction. In this embodiment, the protrusions 360 are provided at three locations in the circumferential direction, equiangularly spaced apart. The protrusions 360 are positioning portions for positioning the first barrel member 20 in the radial direction.

[0037] An elastic member 15 is disposed on an end face 33a of the step portion 33 facing the object side X2. The elastic member 15 elastically deforms in the optical axis direction between the end face 3a and the end face 33a of the first lens 3. The step portion 34 abuts against the first barrel member 20 from the image side X1 to support the first barrel member 20 from the image side X1.

[0038] (First barrel member) Fig. 4 is a perspective view of the first barrel member 20. As shown in Figs. 2 to 4, the first barrel member 20 includes a first tube portion 21 that holds the second lens 4 from the outer periphery side, a second tube portion 22 that holds the third lens 5 to the sixth lens 10 from the outer periphery side, an annular step portion 23 at an end portion on the object side X2 of the second tube portion 22, an annular step portion 24 that protrudes from the inner periphery side from an end portion on the image side X1 of the second tube portion 22, an annular step portion 25 at an end portion on the image side X1 of the second tube portion 22, and a third tube portion 26 that surrounds the outer periphery side of the image-side lens 9.

[0039] The first tube portion 21 is provided at an end portion on the object side X2 with an abutment portion 27 that bends inwardly and abuts against the second lens 4 from the object side X2. The second lens 4 is placed on an end face 23a of the step portion 23 facing the object side X2 via a light blocking sheet 12. The step portion 24 abuts against a flange portion 8b of the object-side lens 8 of the sixth lens 10 from the image side X1, and supports the third lens 5 to the sixth lens 10 from the image side X1.

[0040] The step portion 25 abuts against the step portion 34 in the optical axis direction. This positions the first barrel member 20 relative to the second barrel member 30 in the optical axis direction. The third barrel portion 26 is not in contact with the image-side lens 9 of the sixth lens 10. The third barrel portion 26 has an annular plate portion 28 that protrudes radially inward at the end of the image side X1. The inner peripheral edge of the annular plate portion 28 defines a circular opening 280. An imaging element (not shown) is fixed to the surface of the image side X1 of the annular plate portion 28 so as to close the circular opening 280.

[0041] The inner peripheral surface 220 of the second tube portion 22 is slightly inclined toward the inner peripheral side toward the image side X1. As shown in FIG. 4, the inner peripheral surface 210 of the first tube portion 21 is provided with a rib 211 extending in the optical axis direction along the inner peripheral surface 210. The inner peripheral surface 220 of the second tube portion 22 is provided with a rib 221 extending in the optical axis direction along the inner peripheral surface 220. A plurality of ribs 221 are arranged in the optical axis direction. The ribs 211 and 221 are arranged at the same angular position centered on the optical axis X. As shown in FIG. 2, when the lens group 11 is housed in the first barrel member 20, the rib 211 abuts against the flange portion 5b of the second lens 4 from the radial outside to position the second lens 4 in the radial direction. When the lens group 11 is housed in the first barrel member 20, each rib 221 abuts against the flange portion 5b of the third lens 5, the flange portion 6b of the fourth lens 6, the holder 70 holding the fifth lens 7, and the flange portion 8b of the object-side lens 8 of the sixth lens 10 from the radially outer side, thereby positioning the third lens 5 to the sixth lens 10 in the radial direction.

[0042] 2 and 4, the second cylindrical portion 22 has a plurality of openings 29 provided at positions overlapping at least a portion of the second holding member 72 of the holder 70 when viewed from a direction perpendicular to the optical axis X. The openings 29 are long holes extending through the second cylindrical portion 22 in the circumferential direction. In this embodiment, four openings 29 are provided in the second cylindrical portion 22 at intervals of 90° around the optical axis X.

[0043] (holder) Fig. 5 is a perspective view of the holder 70 of the first embodiment. Fig. 6 is an exploded perspective view of the holder 70 of the first embodiment as seen from the object side X2. Fig. 7 is an exploded perspective view of the holder 70 of the first embodiment as seen from the image side X1. Fig. 8 is a diagram showing the relationship between the first barrel member 20 and the holder 70 in the first embodiment.

[0044] 5 to 8, the holder 70 includes a first holding member 71 held by the second cylinder portion 22 of the first barrel member 20, a second holding member 72 that holds the fifth lens 7, and a guide portion 75.

[0045] The first holding member 71 is annular. The first holding member 71 is press-fitted into the inner circumferential surface 220 of the second tube portion 22. An end surface 711 on the image side X1 of the first holding member 71 is in contact with an end surface 81 of the object-side lens 8. The first holding member 71 has a protruding portion 73 protruding from an inner peripheral edge portion to the object side X2. The protruding portion 73 is inclined inward toward the object side X2. The protruding portion 73 has an inner circumferential surface 731 facing radially inward and an outer circumferential surface 732 (second surface portion) facing radially outward. The inner circumferential surface 731 is in an arc shape centered on the optical axis X. In this embodiment, the inner circumferential surface 731 is annular. The outer circumferential surface 732 is in an arc shape centered on the optical axis X. In this embodiment, the outer circumferential surface 732 is annular. The outer circumferential surface 732 is inclined radially inward toward the object side X2.

[0046] The inner peripheral surface 731 is inclined radially inward toward the object side X2. The inner peripheral surface 731 has the same inclination angle as the inclined surface 82 of the object-side lens 8, and is in contact with the inclined surface 82. Here, the end surface 711 and the inner peripheral surface 731 are textured. Therefore, since the end surface 81 and the inclined surface 82 of the object-side lens 8 are also textured, the frictional resistance when the object-side lens 8 and the first holding member 71 come into contact with each other is large.

[0047] The second holding member 72 is annular. The second holding member 72 is in contact with the inner circumferential surface 220 of the second cylindrical portion 22. and is rotatable around the optical axis X with respect to the first holding member 71. The fifth lens 7 is press-fitted into the central portion of the second holding member 72. An end face 721 on the object side X2 of the second holding member 72 abuts against the flange portion 6b of the fourth lens 6 via the diaphragm 13. The second holding member 72 is provided with an inclined surface 722 inclined toward the image side X1 at the inner peripheral edge portion of the end face 721. The inclined surface 722 is provided with three cutout portions 723. An adhesive is applied to the cutout portions 723 to fix the fifth lens 7.

[0048] The second holding member 72 includes a protruding portion 74 that protrudes from an end surface 724 of the second holding member 72 on the image side X1 to the image side X1. The protruding portion 74 includes an inner peripheral surface 741 (first surface portion) facing radially inward, and an end surface 742 facing the image side X1. The inner peripheral surface 741 and the outer peripheral surface 732 face each other in the radial direction. The inner peripheral surface 741 is in the shape of a circular arc centered on the optical axis X. In this embodiment, the inner peripheral surface 741 is annular. The inner peripheral surface 741 is inclined radially outward toward the image side X1. The inner peripheral surface 741 has the same inclination angle as the outer peripheral surface 732. A slight gap is formed between the inner peripheral surface 741 and the outer peripheral surface 732. The end surface 742 abuts against an end surface 712 of the first holding member 71 facing the object side X2.

[0049] The second holding member 72 has recesses 76 on its outer circumferential surface 720. A plurality of recesses 76 are provided at equal intervals in the radial direction. In this embodiment, the recesses 76 are circular holes. Alternatively, the recesses 76 may be grooves extending in the optical axis direction.

[0050] The guide portion 75 is composed of a protruding portion 73 of the first holding member 71 and a protruding portion 74 of the second holding member 72. The guide portion 75 supports the second holding member 72 rotatably around the optical axis X with respect to the first holding member 71. Here, the inner peripheral surface 741 and the outer peripheral surface 732 are mirror-finished. Therefore, the frictional resistance when the inner peripheral surface 741 and the outer peripheral surface 732 contact each other is small. In addition, the end surface 742 and the end surface 712 are mirror-finished. Therefore, the frictional resistance when the end surface 742 and the end surface 712 contact each other is small. This makes it easy to rotate the second holding member 72 around the optical axis X with respect to the first holding member 71.

[0051] 7, the protruding portion 74 is provided with three notches 77. An adhesive is applied to the notches 77 in order to fix the first holding member 71 and the second holding member 72 together.

[0052] (Lens unit assembly) When assembling the lens unit 1, an assembly operation of making the first barrel member 20 hold the lens group 11 is performed, and then an assembly operation of making the first barrel member 20 hold the second barrel member 30 is performed.

[0053] First, the third lens 5 to the sixth lens 10 are housed in the first barrel member 20 from the object side X2, and the sixth lens 10 is supported on the step portion 24. Thereafter, the elastic member 16 and the second lens 4 are housed in the first barrel member 20, and then the end of the first barrel member 20 on the object side X2 is crimped to form the abutment portion 27. In this way, the lens group 11 is held by the first barrel member 20 from both sides in the optical axis direction.

[0054] Next, the fifth lens 7 is aligned. Specifically, an alignment jig is inserted through an opening 29 formed in the first barrel member 20, and the second holding member 72 is rotated around the optical axis X relative to the first holding member 71. When the alignment jig is inserted, the tip of the jig is fitted into the recess 76.

[0055] When aligning the fifth lens 7, monitor light is incident from the second lens 4 side, and the monitor light is detected on the image side X1. Based on the monitor results of the resolution, the angle of view, the light amount distribution, etc., the angular position of the second holding member 72 relative to the first holding member 71 is adjusted. The force in the optical axis direction applied to the lens group 11 generated when the material 72 rotates relative to the first holding member 71 is released by the elastic member 16 being compressed in the optical axis direction, so that the holding force of the lens group 11 in the optical axis direction is maintained constant.

[0056] When the alignment of the fifth lens 7 is completed, adhesive is applied to the cutout portion 77 from the opening 29. This causes adhesive to be supplied between the first holding member 71, the second holding member 72, and the first barrel member 20. For example, a photocurable adhesive is used as this adhesive. As a result, the first holding member 71, the second holding member 72, and the first barrel member 20 are fixed by the adhesive provided at a position visible through the opening 29 from the radial outside, and the first barrel member 20 is completed.

[0057] Next, adhesive is applied to step 38 on the inner circumferential surface of second barrel member 30, and first barrel member 20 is inserted into second barrel member 30. At this time, step 25 of first barrel member 20 is brought into contact with step 34 of second barrel member 30.

[0058] Next, the elastic member 15 is placed on the end face 33a of the step portion 33. Thereafter, the first lens 3 is supported on the end face 33a of the step portion 33 via the elastic member 15. Thereafter, the end of the object side X2 of the second barrel member 30 is crimped to form the abutment portion 35. Here, when the first lens 3 is held by the second barrel member 30, the end face 3a of the first lens 3 is in surface contact with the tip of the annular protrusion 4c.

[0059] (Action and effect) According to the lens unit 1 of this embodiment, the second holding member 72 that holds the fifth lens 7 can be rotated from the outside of the first barrel member 20 with respect to the first holding member 71. This allows centering of the fifth lens 7 to be performed so that the amount of decentering deviation of the fifth lens 7 is reduced by rotating the second holding member 72. Therefore, the lens unit of this embodiment makes it easier to center the fifth lens 7 compared to a case in which the lens is centered by moving the lens in two axial directions that are perpendicular to the optical axis X and perpendicular to each other.

[0060] The fifth lens 7 is a lens among the multiple lenses that is adjacent to the object side X2 of the aperture 13. This makes it possible to center the lens that has the greatest effect on the optical performance of the lens unit 1.

[0061] The holder 70 includes a guide portion 75 that supports the second holding member 72 rotatably about the optical axis X relative to the first holding member 71. This makes it easy to rotate the second holding member 72 relative to the first holding member 71.

[0062] The guide portion 75 includes an arc-shaped inner circumferential surface 741 provided on the second holding member 72, facing radially inward, and centered on the optical axis X, and an arc-shaped outer circumferential surface 732 provided on the first holding member 71, facing radially outward, and centered on the optical axis X. The inner circumferential surface 741 and the outer circumferential surface 732 face each other in the radial direction. In this case, the inner circumferential surface 741 is inclined radially outward toward the first holding member 71, and the outer circumferential surface 732 is inclined radially inward toward the second holding member 72. This makes it easy to align the centers of the first holding member 71 and the second holding member 72.

[0063] In this embodiment, the second holding member has a recess 76 on its outer circumferential surface. With this, when an alignment jig is inserted through opening 29 and second holding member 72 is rotated, the tip of the jig can be fitted into recess 76, making it easy to hold second holding member 72 with the jig.

[0064] The lens unit 1 has an elastic member 16 provided between any of the lenses among the plurality of lenses. With this, after the lens group 11 is assembled into the first barrel member 20, Even if a force in the optical axis direction is applied to lens group 11 when second holding member 72 is rotated, the force in the optical axis direction applied to lens group 11 when second holding member 72 is rotated is released by elastic member 16 being compressed in the optical axis direction, so that the second holding member can be easily rotated.

[0065] The elastic member 16 is provided between the second lens 4 and the third lens 5, which has the largest on-axis surface distance among any of the multiple lenses. In this way, even if the compression amount of the elastic member 16, i.e., the on-axis surface distance between the second lens 4 and the third lens 5, changes when the second holding member 72 is rotated, the optical performance of the lens unit 1 is unlikely to be affected.

[0066] (Embodiment 2) Next, a lens unit of the second embodiment will be described. The lens unit of the second embodiment differs from the lens unit 1 of the first embodiment in the configuration of the holder 70. Therefore, in the second embodiment, the same configurations as those of the first embodiment are given the same reference numerals and the description thereof may be omitted. Fig. 9 is a perspective view of the holder 70 of the second embodiment. Fig. 10 is an exploded perspective view of the holder 70 of the second embodiment as viewed from the object side X2. Fig. 11 is a diagram showing the relationship between the first barrel member 20 and the holder 70 in the second embodiment.

[0067] 9 to 11, the holder 70 includes a first holding member 71 held by the second tube portion 22 of the first barrel member 20, a second holding member 72 holding the fifth lens 7, a guide portion 75, and an adjustment portion 78.

[0068] The first holding member 71 is annular. The first holding member 71 is press-fitted into the inner circumferential surface 220 of the second tube portion 22. An end face 711 on the image side X1 of the first holding member 71 contacts an end face 81 of the object-side lens 8. Here, in the object-side lens 8, an end face 85 of the lens main body portion 8a, an outer circumferential surface 86 of the lens main body portion 8a, and an end face 81 of the flange portion 8b are coated with black ink.

[0069] The first holding member 71 has an inner circumferential surface 751 (first surface portion) facing radially inward. The inner circumferential surface 751 has an arc shape centered on the optical axis X. In this embodiment, the inner circumferential surface 751 is annular. A female screw portion 781 is provided on the inner circumferential surface 751.

[0070] The second holding member 72 is annular. The second holding member 72 is not in contact with the inner circumferential surface 220 of the second tube portion 22 and is rotatable around the optical axis X with respect to the first holding member 71. The second holding member 72 includes an annular main body portion 725 and a tube portion 726 protruding from the image side X1 of the main body portion 725. The fifth lens 7 is press-fitted into the central portion of the main body portion 725. The outer diameter dimension of the tube portion 726 is smaller than that of the main body portion 725. The tube portion 726 is inserted inside the first holding member 71. The tube portion 726 includes an outer peripheral surface 752 (second surface portion) facing radially outward. The inner peripheral surface 751 and the outer peripheral surface 752 face each other in the radial direction. The outer peripheral surface 752 is in the shape of a circular arc centered on the optical axis X. In this embodiment, the outer peripheral surface 752 is annular. A male screw portion 782 is provided on the outer peripheral surface 752. The male thread portion 782 is screwed into the female thread portion 781 .

[0071] An end face 721 on the object side X2 of the second holding member 72 abuts against the flange portion 6b of the fourth lens 6 via the diaphragm 13. The second holding member 72 has an inclined surface 722 that inclines toward the image side X1 on the inner circumferential edge portion of the end face 721. An adhesive is applied to the inclined surface 722 to fix the fifth lens 7.

[0072] The guide portion 75 is made up of an inner circumferential surface 751 of the first holding member 71 and an outer circumferential surface 752 of the second holding member 72. The guide portion 75 supports the second holding member 72 relative to the first holding member 71 so as to be rotatable about the optical axis X. The adjustment portion 78 is made up of a female thread portion 781 and a male thread portion 782. As a result, the adjustment portion 78 adjusts the second holding member 72 relative to the first holding member 71. When rotated, the second holding member 72 is moved in the optical axis direction.

[0073] When assembling the lens unit 1, alignment of the fifth lens 7 and focus adjustment of the first barrel member 20 are performed simultaneously. When making these adjustments, similar to the first embodiment, an alignment jig is inserted through an opening 29 formed in the first barrel member 20, and the second holding member 72 is rotated around the optical axis X relative to the first holding member 71.

[0074] When aligning the fifth lens 7 and adjusting the focus of the first barrel member 20, monitor light is incident from the second lens 4 side and detected on the image side X1, and the angular position of the second holding member 72 relative to the first holding member 71 is adjusted based on the monitor results such as resolution, angle of view, and light quantity distribution.

[0075] When the alignment of the fifth lens 7 and the focus adjustment of the first barrel member 20 are completed, adhesive is applied from the opening 29 to the gap S between the first holding member 71 and the second holding member 72. This causes the adhesive to be supplied between the first holding member 71, the second holding member 72, and the first barrel member 20. The first holding member 71, the second holding member 72, and the first barrel member 20 are fixed together by the adhesive, and the first barrel member 20 is completed.

[0076] (Action and effect) The holder 70 includes an adjustment unit 78 that moves the second holding member 72 in the optical axis direction relative to the first holding member 71 when the second holding member 72 rotates relative to the first holding member 71. In this case, the adjustment unit 78 includes a female screw portion 781 provided on the first holding member 71, and a male screw portion 782 provided on the second holding member 72 and screwed into the female screw portion 781. This makes it possible to adjust the position of the fifth lens 7 in the optical axis direction while performing centering of the fifth lens 7.

[0077] (Embodiment 3) Next, a lens unit of embodiment 3 will be described. The lens unit of embodiment 3 differs from the lens unit 1 of embodiment 1 in the configuration of the holder 70. Therefore, in embodiment 3, the same configurations as those of embodiment 1 are given the same reference numerals and descriptions thereof may be omitted. Fig. 12 is a perspective view of the holder 70 of embodiment 3. Fig. 13 is an exploded perspective view of the holder 70 of embodiment 3 as viewed from the object side X2. Fig. 14 is a diagram showing the relationship between the first barrel member 20 and the holder 70 in embodiment 3.

[0078] 12 and 13, the holder 70 includes a first holding member 71 held by the second tube portion 22 of the first barrel member 20, a second holding member 72 holding the fifth lens 7, a guide portion 75, and an adjustment portion 78.

[0079] The first holding member 71 is annular. The first holding member 71 is press-fitted into the inner circumferential surface 220 of the second tube portion 22. An end face 711 on the image side X1 of the first holding member 71 contacts an end face 81 of the object-side lens 8. Here, in the object-side lens 8, an end face 85 of the lens main body portion 8a, an outer circumferential surface 86 of the lens main body portion 8a, and an end face 81 of the flange portion 8b are coated with black ink.

[0080] The first holding member 71 has an inner circumferential surface 751 (first surface portion) facing radially inward, and a cam groove 783 formed in a spiral shape in the optical axis direction. The inner circumferential surface 751 is in the shape of a circular arc centered on the optical axis X. In this embodiment, the inner circumferential surface 751 is annular. The cam groove 783 is a groove cut out in a spiral shape from the end of the first holding member 71 on the object side X2 to the image side X1.

[0081] The second holding member 72 is annular. The second holding member 72 is in contact with the inner circumferential surface 220 of the second cylindrical portion 22. The second holding member 72 is not in contact with the first holding member 71 and is rotatable around the optical axis X with respect to the first holding member 71. The second holding member 72 includes an annular main body portion 725 and a tube portion 726 protruding from the image side X1 of the main body portion 725. The fifth lens 7 is press-fitted into the central portion of the main body portion 725. The outer diameter dimension of the tube portion 726 is smaller than that of the main body portion 725. The tube portion 726 is inserted inside the first holding member 71. The tube portion 726 includes an outer peripheral surface 752 (second surface portion) facing radially outward, and a cam pin 784 protruding radially outward. The inner peripheral surface 751 and the outer peripheral surface 752 face each other in the radial direction. The outer peripheral surface 752 is in the shape of a circular arc centered on the optical axis X. In this embodiment, the outer peripheral surface 752 is annular. The cam pin 784 is inserted into the cam groove 783.

[0082] An end face 721 on the object side X2 of the second holding member 72 abuts against the flange portion 6b of the fourth lens 6 via the diaphragm 13. The second holding member 72 has an inclined surface 722 that inclines toward the image side X1 on the inner circumferential edge portion of the end face 721. An adhesive is applied to the inclined surface 722 to fix the fifth lens 7.

[0083] The guide portion 75 is composed of an inner circumferential surface 751 of the first holding member 71 and an outer circumferential surface 752 of the second holding member 72. The guide portion 75 supports the second holding member 72 rotatably around the optical axis X relative to the first holding member 71. The adjustment portion 78 is composed of a cam groove 783 and a cam pin 784. As a result, when the second holding member 72 rotates relative to the first holding member 71, the cam pin 784 moves along the cam groove 783, thereby moving the second holding member 72 in the optical axis direction relative to the first holding member 71.

[0084] When assembling the lens unit 1, the angular position of the second holding member 72 relative to the first holding member 71 is adjusted, as in the second embodiment. When the alignment of the fifth lens 7 and the focus adjustment of the first barrel member 20 are completed, adhesive is applied from the opening 29 to the gap S between the first holding member 71 and the second holding member 72. This supplies adhesive between the first holding member 71, the second holding member 72, and the first barrel member 20. The first holding member 71, the second holding member 72, and the first barrel member 20 are fixed together by the adhesive, and the first barrel member 20 is completed.

[0085] (Action and effect) The holder 70 includes an adjustment unit 78 that moves the second holding member 72 in the optical axis direction relative to the first holding member 71 when the second holding member 72 rotates relative to the first holding member 71. In this case, the adjustment unit 78 includes a cam groove 783 that is provided in the first holding member 71 and formed in a spiral shape in the optical axis direction, and a cam pin 784 that is provided in the second holding member 72 and inserted into the cam groove 783. This makes it possible to adjust the position of the fifth lens 7 in the optical axis direction while centering the fifth lens 7.

[0086] (Other embodiments) In the first embodiment, the holder 70 includes the guide portion 75, but in other embodiments, the holder 70 does not need to include the guide portion 75. In this case, it is only necessary that the second holding member 72 is rotatable around the optical axis X relative to the first holding member 71.

[0087] In the first embodiment, the inner circumferential surface 741 (first surface portion) and the outer circumferential surface 732 (second surface portion) are inclined surfaces, but are not limited thereto. For example, in other embodiments, the inner circumferential surface 741 (first surface portion) and the outer circumferential surface 732 (second surface portion) may be surfaces extending in the optical axis direction.

[0088] In the first embodiment, the guide portion 75 is composed of the protrusion 73 of the first holding member 71 and the protrusion 74 of the second holding member 72, but is not limited to this. For example, in other embodiments, the guide portion may be composed of a protrusion provided on one side of the first holding member 71 and the second holding member 72, and a recess provided on the other side of the first holding member 71 and the second holding member 72 into which the protrusion fits. In this case, a first surface portion is provided on one side of the protrusion and the recess, and the protrusion A second surface portion is provided on the other side of the recess.

[0089] In the third embodiment, one cam groove 783 and one cam pin 784 are provided, but in other embodiments, a plurality of cam grooves 783 and a plurality of cam pins 784 may be provided. For example, when three cam grooves 783 and three cam pins 784 are provided at equal intervals, the cam grooves 783 and the cam pins 784 are exposed to the outside from four openings 29 provided at 90° intervals. In this way, the positions of the cam grooves 783 and the cam pins 784 can be confirmed from the openings 29, making it easy to apply adhesive to the cam grooves 783 and the cam pins 784 from the openings 29.

[0090] The present technology can be configured as follows.

[0091] (1) A plurality of lenses including a centering lens, the plurality of lenses being arranged in an optical axis direction along an optical axis; a first barrel member that houses the plurality of lenses therein; a diaphragm provided between any of the plurality of lenses; and a holder that holds the centering lens from a radially outer side and is held by the first barrel member; having The holder includes: a first holding member held by the first barrel member; a second holding member that holds the centering lens, is not in contact with an inner circumferential surface of the first barrel member, and is rotatable about the optical axis relative to the first holding member; Equipped with the first barrel member includes a plurality of openings provided at positions overlapping at least a portion of the second holding member when viewed from a direction perpendicular to the optical axis, A lens unit, characterized in that the second holding member is rotated about the optical axis, thereby centering the centering lens.

[0092] (2) The lens unit described in (1) is characterized in that the centering lens is a lens among the plurality of lenses that is adjacent to either the object side of the aperture or the image side of the aperture.

[0093] (3) The lens unit described in (1) or (2) is characterized in that the holder includes a guide portion that supports the second holding member rotatably around the optical axis relative to the first holding member.

[0094] (4) the guide portion includes a first surface portion provided on one side of the first holding member and the second holding member, facing radially inward, and having an arc-shaped configuration centered on the optical axis; and a second surface portion provided on the other side of the first holding member and the second holding member, facing radially outward, and having an arc-shaped configuration centered on the optical axis; The lens unit described in (3) above, wherein the first surface portion and the second surface portion face each other in a radial direction.

[0095] (5) the first surface portion is inclined radially outward toward the other side of the first holding member and the second holding member, The lens unit described in (4) is characterized in that the second surface portion is inclined radially inward toward one side of the first holding member and the second holding member.

[0096] (6) The lens unit described in any one of (3) to (5), characterized in that the holder has an adjustment portion that moves the second holding member in the optical axis direction relative to the first holding member when the second holding member rotates relative to the first holding member.

[0097] (7) The lens unit described in (6), wherein the adjustment portion comprises a female thread portion provided on one side of the first retaining portion and the second retaining portion, and a male thread portion provided on the other side of the first retaining portion and the second retaining portion and screwed into the female thread portion.

[0098] (8) The lens unit described in (6), characterized in that the adjustment portion comprises a cam groove provided on one side of the first retaining portion and the second retaining portion and formed spirally in the optical axis direction, and a cam pin provided on the other side of the first retaining portion and the second retaining portion and inserted into the cam groove.

[0099] (9) The lens unit described in any one of (1) to (8), wherein the second holding member has a recess on an outer circumferential surface.

[0100] (10) The lens unit described in any one of (1) to (9) above, further comprising an elastic member provided between any of the plurality of lenses.

[0101] (11) The lens unit described in (10) above, wherein the elastic member is provided between any of the plurality of lenses between which an on-axis surface distance is greatest.

[0102] (12) The lens unit described in any one of (1) to (11) is characterized in having an object-side lens arranged on the object side of the plurality of lenses, and a second barrel member that houses the object-side lens inside and holds the first barrel member inside. [Explanation of symbols]

[0103] 1...lens unit, 2...lens barrel, 3...first lens, 3a...end surface, 4...second lens, 4a...lens body, 4b...flange, 4c...annular protrusion, 5...third lens, 5a...lens body, 5b...flange, 6...fourth lens, 6a...lens body, 6b...flange, 7...fifth lens (centering lens), 7a...lens body, 7b...flange, 8...object-side lens, 8a...lens body, 8b...flange, 8c...annular protrusion, 9...image-side lens, 9a...lens body, 9b...flange, 10...sixth lens, 11...lens group, 12...light-shielding sheet, 15...elastic member, 16...elastic member, 20... First barrel member, 21...first barrel portion, 22...second barrel portion, 23...step portion, 23a...end surface, 24...step portion, 25...step portion, 26...third barrel portion, 27...contact portion, 28...annular plate portion, 29...opening, 30...second barrel member, 31...first barrel portion, 32...second barrel portion, 33...step portion, 33a...end surface, 34...step portion, 35...contact portion, 36...inner circumferential surface, 38...step portion, 70...holder, 71...first holding member, 72...second holding member, 73...projection portion, 74...projection portion, 75...guide portion, 76...recess, 77...notch portion, 78...adjustment portion, 81...end surface, 82...inclined surface, 83...tip surface, 85...end surface, 86...outer circumferential surface, 210...inner circumferential surface, 211...rib , 220...inner surface, 221...rib, 280...circular opening, 360...protrusion, 711...end face, 712...end face, 720...outer surface, 721...end face, 722...inclined surface, 723...notch portion, 724...end face, 725...main body portion, 726...tubular portion, 731...inner surface, 732...outer surface, 741...inner surface, 742...end face, 751...inner surface, 752...outer surface, 781...female thread portion, 782...male thread portion, 783...cam groove, 784...cam pin, S...gap, X...optical axis, X1...image side, X2...object side.

Claims

1. A plurality of lenses including a centering lens, the plurality of lenses being arranged in an optical axis direction along an optical axis; a first barrel member that houses the plurality of lenses therein; a diaphragm provided between any of the plurality of lenses; and a holder that holds the centering lens from a radially outer side and is held by the first barrel member; having The holder includes: a first holding member held by the first barrel member; a second holding member that holds the centering lens, is not in contact with an inner circumferential surface of the first barrel member, and is rotatable about the optical axis relative to the first holding member; Equipped with the first barrel member includes a plurality of openings provided at positions overlapping at least a portion of the second holding member when viewed from a direction perpendicular to the optical axis, A lens unit, characterized in that the second holding member is rotated about the optical axis, thereby centering the centering lens.

2. 2. The lens unit according to claim 1, wherein the centering lens is a lens among the plurality of lenses that is adjacent to one of the object side of the aperture and the image side of the aperture.

3. 3. The lens unit according to claim 1, wherein the holder includes a guide portion that supports the second holding member rotatably about the optical axis relative to the first holding member.

4. the guide portion includes a first surface portion provided on one side of the first holding member and the second holding member, facing radially inward, and having an arc-shaped configuration centered on the optical axis; and a second surface portion provided on the other side of the first holding member and the second holding member, facing radially outward, and having an arc-shaped configuration centered on the optical axis. The lens unit according to claim 3 , wherein the first surface portion and the second surface portion face each other in a radial direction.

5. the first surface portion is inclined radially outward toward the other side of the first holding member and the second holding member, The lens unit according to claim 4 , wherein the second surface portion is inclined radially inward toward one of the first holding member and the second holding member.

6. The lens unit according to claim 3 , wherein the holder includes an adjustment portion that moves the second holding member in the optical axis direction relative to the first holding member when the second holding member rotates relative to the first holding member.

7. The lens unit according to claim 6, characterized in that the adjustment portion comprises a female thread portion provided on one side of the first holding portion and the second holding portion, and a male thread portion provided on the other side of the first holding portion and the second holding portion and screwed into the female thread portion.

8. The adjustment portion includes a cam groove provided on one side of the first holding portion and the second holding portion and formed in a spiral shape in the optical axis direction, and a cam pin provided on the other side of the first holding portion and the second holding portion and inserted into the cam groove. The lens unit according to claim 6.

9. The lens unit according to claim 1 , wherein the second holding member has a recess on an outer circumferential surface thereof.

10. 2. The lens unit according to claim 1, further comprising an elastic member provided between any of the plurality of lenses.

11. 11. The lens unit according to claim 10, wherein the elastic member is provided between any of the plurality of lenses between which an on-axis surface distance is largest.

12. 2. The lens unit according to claim 1, further comprising: an object-side lens arranged on the object side of the plurality of lenses; and a second barrel member that houses the object-side lens therein and holds the first barrel member therein.

Images