JP2017223829A - Lens unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens unit that enables an achievement of miniaturization of a lens, and strength securement of a lens frame without spoiling optical performances.SOLUTION: An incident side lens has: a cylindrical first outer perimeter surface; a first gradient surface that is located at a position nearer to an optical axis than the first outer perimeter surface, and makes a distance from the optical axis smaller as progressing from an incidence side to an emission side. An emitting side lens has: a cylindrical second outer perimeter surface; a second gradient surface that is located at a position nearer to the optical axis than the second outer perimeter surface, and makes a distance from the optical axis larger as progressing from the incident side to the emitting side. A lens frame has: a first frame part that has a positioning part surrounding the cylindrical outer perimeter surface of each lens, and positioning a position in the optical axis; a second frame part that surrounds the gradient surface of each lens, in which a frame inner surface part of the second frame part has: an incident side area in which a distance in a radial direction from the optical axis is smaller on the emitting side rather than that on the incident side, and which extends along the first gradient surface; and an emitting side area in which a distance in the radial direction from the optical axis is larger on the emitting side rather than that on the incident side, and which extends along the second gradient surface.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a lens unit having a lens and a lens frame that holds the lens.

  In recent years, imaging devices are mounted on various devices such as portable information terminals, and in order to contribute to the downsizing and improvement of design of such devices, there is an increasing demand for downsizing the imaging device. For example, as in Patent Document 1 to Patent Document 5, by making the peripheral shape of the lens constituting the imaging optical system a non-circular shape in which a part of a circular shape (cylinder) centered on the optical axis is omitted, The front projection area of the lens is reduced, and the entire imaging device including the lens can be reduced in size. As this type of lens having a non-circular peripheral shape, a D-cut lens having one flat cut surface on the peripheral edge, an oval lens having two flat cut surfaces on the peripheral edge, and the like are known. ing.

JP 2013-003180 A JP-A-2015-114400 JP 2006-267391 A JP 2010-243663 A JP2013-105049A

  When the lens having the cut surface as described above is used, the light reflected by the cut surface reaches the imaging surface, and flare or ghost may occur, which may reduce the image quality of the captured image. In particular, the smaller the distance from the optical axis to the cut surface in the radial direction of the lens around the optical axis, the smaller the lens, but on the other hand, the closer to the optical axis, the easier the cut surface area becomes, Increased risk of harmful reflected light. For this reason, it is necessary to form a cut surface at a position having a margin with respect to the effective range of the lens in the radial direction, and the reduction in size of the lens is restricted.

  Further, when a lens having a cut surface as described above is used for the purpose of miniaturization, a portion surrounding the outside of the cut surface of the lens is thinly formed so that the lens frame for holding the lens can be miniaturized. There are many cases. Then, ensuring the strength at this thin portion becomes an issue. Further, there is a problem that a weld line is likely to be generated when the lens frame is formed in the thin portion.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a lens unit that can realize downsizing of a lens and ensuring strength of a lens frame without impairing optical performance.

  The present invention relates to a lens unit for inserting and holding an incident side lens located on the incident side in the optical axis direction and an emission side lens located on the emission side in a holding hole of a common lens frame. The lens unit according to the first aspect of the present invention has the following configuration. The incident side lens has a first outer peripheral surface having a cylindrical shape centered on the optical axis at a peripheral edge in the radial direction centered on the optical axis, and a distance from the optical axis in the radial direction more than the first outer peripheral surface. A first inclined surface that is small and reduces the radial distance from the optical axis as it proceeds from the incident side to the exit side in the optical axis direction. The exit side lens has a second outer peripheral surface having a cylindrical shape centered on the optical axis at a peripheral edge in the radial direction centered on the optical axis, and a distance from the optical axis in the radial direction more than the second outer peripheral surface. A second inclined surface that is small and increases the distance in the radial direction from the optical axis as it proceeds from the incident side to the exit side in the optical axis direction. The lens frame includes a first frame portion that surrounds the first outer peripheral surface and the second outer peripheral surface of the incident side lens, and a second frame portion that surrounds the first inclined surface and the second inclined surface. . The first frame portion includes an incident-side positioning portion that determines the position of the incident-side lens in the optical axis direction and an emission-side positioning portion that determines the position of the emission-side lens in the optical axis direction. In the second frame portion, as the inner surface of the holding hole, the incident side region along the first inclined surface of the incident side lens positioned by the incident side positioning portion, and the second of the emission side lens positioned by the emission side positioning portion. A frame inner surface portion having an exit side region along the inclined surface is provided. The incident side area of the inner surface of the frame has a smaller radial distance from the optical axis on the exit side than the incident side in the optical axis direction, and the exit side area of the inner surface of the frame is light on the exit side than the incident side in the optical axis direction. Large radial distance from shaft.

  The incident side region of the inner surface of the frame has the same formation range in the optical axis direction and the radial direction as the first inclined surface of the incident side lens, and the inclined direction with respect to the optical axis is opposite to the first inclined surface of the incident side lens. The emission side region of the inner surface of the frame has a relationship intersecting the virtual inclined surface, and the formation range in the optical axis direction and the radial direction is the same as the second inclined surface of the emission side lens, and the inclination direction with respect to the optical axis is the emission side lens. It is preferable to have a relationship that intersects with a virtual inclined surface that is opposite to the second inclined surface.

  The incident side area of the inner surface of the frame has a planar shape substantially parallel to the first inclined surface of the incident side lens, and the emission side area of the inner surface of the frame has a planar shape substantially parallel to the second inclined surface of the emission side lens. It is preferable that

  The lens unit according to the second aspect of the present invention has the following configuration. The incident side lens has a first outer peripheral surface having a cylindrical shape centered on the optical axis at a peripheral edge in the radial direction centered on the optical axis, and a distance from the optical axis in the radial direction more than the first outer peripheral surface. A first inclined surface that is small, non-parallel and non-perpendicular to the optical axis. The exit side lens has a second outer peripheral surface having a cylindrical shape centered on the optical axis at a peripheral edge in the radial direction centered on the optical axis, and a distance from the optical axis in the radial direction more than the second outer peripheral surface. A second inclined surface that is small, non-parallel and non-perpendicular to the optical axis. The lens frame includes a first frame portion that surrounds the first outer peripheral surface and the second outer peripheral surface of the incident side lens, and a second frame portion that surrounds the first inclined surface and the second inclined surface. . The first frame portion includes an incident-side positioning portion that determines the position of the incident-side lens in the optical axis direction and an emission-side positioning portion that determines the position of the emission-side lens in the optical axis direction. The second frame portion has an inner surface portion of the holding hole as an inner surface of the holding hole, which is an intermediate portion that is smaller in the radial direction from the optical axis than the respective end portions on the incident side and the emission side in the optical axis direction. The incident side lens is held in the holding hole of the lens frame in a first direction that decreases the radial distance from the optical axis as the first inclined surface advances from the incident side to the emission side in the optical axis direction. The frame inner surface portion of the frame restricts insertion of the first inclined surface from the incident side into the holding hole when the incident side lens is opposite to the first direction in the optical axis direction. The exit side lens is held in the holding hole of the lens frame in a second direction that increases the radial distance from the optical axis as the second inclined surface advances from the entrance side to the exit side in the optical axis direction. The frame inner surface portion of the frame restricts insertion of the second inclined surface from the exit side into the holding hole when the exit side lens is opposite to the second direction in the optical axis direction.

  Further, the frame inner surface portion of the lens frame restricts insertion of the first inclined surface from the exit side into the holding hole when the entrance side lens is in the first orientation, and the exit side lens is in the second orientation. In some cases, the insertion of the second inclined surface from the incident side into the holding hole may be restricted.

  A plane substantially parallel to the first inclined surface facing the first inclined surface in a state where the incident side lens is positioned in the optical axis direction by the incident side positioning portion as a portion constituting the frame inner surface portion in the second frame portion. The incident-side inclined inner surface, and the emission-side inclined inner surface facing the second inclined surface in a state where the emission-side lens is positioned in the optical axis direction by the emission-side positioning portion and substantially parallel to the second inclined surface It is preferable to have.

  The lens unit of each aspect configures the incident side positioning portion as a plane that is substantially perpendicular to the optical axis and faces the incident side in the optical axis direction, and the incident side lens abuts on the incident side positioning portion from the incident side to the optical axis direction. It is preferable to have a first reference plane whose position at is determined. In addition, the exit side positioning portion is configured as a plane that is substantially perpendicular to the optical axis and faces the exit side in the optical axis direction, and the exit side lens is in contact with the exit side positioning portion from the exit side to determine the position in the optical axis direction. A second reference plane may be provided.

  In the lens unit of each aspect of the present invention, a light shielding member may be attached to the lens frame. For example, an exit-side light shielding member that is attached to the lens frame at a position on the exit side relative to the exit-side lens in the optical axis direction, or an incident-side light-shielding member that is attached to the lens frame at a position closer to the entrance side than the incident side lens in the optical axis direction Can be provided. The exit-side light blocking member blocks at least a part of the light that is reflected by the second inclined surface of the exit-side lens and travels toward the exit side. The incident side light blocking member blocks at least a part of the light traveling from the incident side toward the first inclined surface of the incident side lens.

  According to the present invention, the incident side lens and the exit side lens each have the second inclined surface with the first inclined surface having a shape that makes it difficult for the reflected light to reach the imaging surface. It is possible to reduce the size of the incident side lens and the exit side lens by suppressing the harmful reflected light and bringing the formation position of each inclined surface closer to the optical axis. In the lens frame, the second frame portion surrounding the first inclined surface of the incident side lens and the second inclined surface of the exit side lens has an optical axis at an intermediate portion in the optical axis direction corresponding to each inclined surface. The inner surface of the frame is reduced in the radial direction from the lens, and the strength of the second frame can be increased by increasing the thickness of the second frame without increasing the size of the lens frame. Therefore, it is possible to obtain a lens unit that realizes downsizing of the lens and ensuring the strength of the lens frame without impairing the optical performance.

It is a sectional side view of the imaging device which has 2 group lens unit to which this invention is applied. It is a disassembled perspective view of a 2 group lens unit. It is a perspective view of a 2nd group frame. It is a sectional side view of a 2 group lens unit. It is a sectional side view of the lower half part of the 2nd group lens unit which showed virtually the state where the direction of each optical axis direction of the 1st lens and the 2nd lens was reversed. It is a sectional side view of the 2 group lens unit of another embodiment. It is a sectional side view of the lens unit of the comparative example different from embodiment of this invention.

  The imaging optical system of the imaging apparatus 10 whose cross section is shown in FIG. 1 includes a first group G1, a second group G2, a third group G3, and a fourth group G4, and includes a first prism PR1 included in the first group G1. The second prism PR2 located on the image side of the fourth group G4 is a bending optical system that reflects the light beam at substantially right angles. The first group G1 includes a first lens L1, a first prism PR, and a second lens L2 in order from the subject (object) side. The second group G2 includes a first lens (incident side lens) L3 and a second lens (exit side lens) L4 in order from the subject side. The second group G2 to the fourth group G4 are each a lens group that does not include a reflecting element such as a prism. The image sensor 11 is provided at a position facing the exit surface of the second prism PR2. The optical axis passing through the first lens L1 of the first group G1 is the first optical axis O1, the optical axis passing from the second lens L2 of the first group G1 to the fourth group G4 is the second optical axis O2, and the second prism PR2. The optical axis from the first to the imaging sensor 11 is defined as a third optical axis O3. The first optical axis O1 and the third optical axis O3 are substantially parallel to each other and are substantially perpendicular to the second optical axis O2.

  The imaging device 10 has a long housing 12 in the direction along the second optical axis O2, the first group G1 is supported near one end in the longitudinal direction of the housing 12, and the fourth group G4 near the other end in the longitudinal direction. The second prism PR2 and the image sensor 11 are provided. A second group frame (lens frame) 13 and a third group frame 14 are supported in the middle of the casing 12 in the longitudinal direction. The second group frame 13 is a lens frame that holds the second group G2, and the third group frame 14 is a lens frame that holds the third group G3. The second group G2 is assembled to the second group frame 13 to form a second group lens unit 15.

  Details of the second group lens unit 15 will be described with reference to FIG. In the following description, the direction along the second optical axis O2 is defined as the optical axis direction. With the second group lens unit 15 as a reference, the side where the first group G1 is located is the incident side in the optical axis direction, and the side where the second prism PR2 is located from the third group G3 is the outgoing side in the optical axis direction. Also, the direction along the first optical axis O1 and the third optical axis O3 is the front-rear direction of the imaging apparatus 10, and the side on which the incident surface of the first lens L1 faces is the front, and the side on which the exit surface of the first lens L1 faces is the rear. And Further, a direction orthogonal to the first optical axis O1, the second optical axis O2, and the third optical axis O3 (a direction orthogonal to the paper surface of FIGS. 1 and 4) is defined as the width direction of the imaging device 10.

  As shown in FIG. 4, the first lens L3 of the second group G2 is a biconvex lens in which both the entrance surface 20 and the exit surface 21 are convex surfaces. The first lens L3 is provided with an annular peripheral portion 22 having a substantially constant thickness in the optical axis direction at the peripheral edge in the radial direction centered on the second optical axis O2. The annular peripheral portion 22 connects the incident peripheral surface 22a positioned at the peripheral edge of the incident surface 20, the reference surface (first reference surface) 22b positioned at the peripheral edge of the exit surface 21, and the incident peripheral surface 22a and the reference surface 22b. It has an outer peripheral surface (first outer peripheral surface) 22c. The incident peripheral surface 22a and the reference surface 22b are planes substantially perpendicular to the second optical axis O2, and the outer peripheral surface 22c is a cylindrical surface centered on the second optical axis O2.

  The first lens L3 has a shape in which a part of a peripheral edge facing the rear side of the imaging device 10 is cut out from a rotationally symmetric body having the second optical axis O2 as the center, and is a front-rear direction rather than a size (diameter) in the width direction. The size of is small. A cut surface (first inclined surface) 25 that connects the entrance surface 20 and the exit surface 21 is formed in the cutout portion of the first lens L3. The cut surface 25 is a plane that is non-parallel and non-perpendicular to the second optical axis O2, and is inclined so as to reduce the radial distance from the second optical axis O2 as it proceeds from the incident surface 20 to the exit surface 21. doing.

  As shown in FIG. 4, the second lens L4 of the second group G2 is a concave meniscus lens in which the curvature of the exit surface 31 that is a concave surface is larger than that of the incident surface 30 that is a convex surface. The second lens L4 is provided with an annular peripheral edge 32 having a substantially constant thickness in the optical axis direction at the peripheral edge in the radial direction centered on the second optical axis O2. A step portion 33 is formed between the annular peripheral edge portion 32 and the incident surface 31 and is located closer to the second optical axis O2 than the annular peripheral edge portion 32. The annular peripheral portion 32 connects the reference surface (second reference surface) 32a positioned at the peripheral edge of the stepped portion 33, the injection peripheral surface 32b positioned at the peripheral edge of the injection surface 31, and the reference surface 32a and the injection peripheral surface 32b. It has an outer peripheral surface (second outer peripheral surface) 32c. The reference surface 32a and the emission peripheral surface 32b are flat surfaces that are substantially perpendicular to the second optical axis O2, and the outer peripheral surface 32c is a cylindrical surface that is centered on the second optical axis O2.

  The second lens L4 has a shape in which a part of a peripheral edge facing the rear side of the imaging device 10 is cut out from a rotationally symmetric body having the second optical axis O2 as the center, and is a front-rear direction rather than a size (diameter) in the width direction. The size of is small. A cut surface (second inclined surface) 35 that connects the entrance surface 30 and the exit surface 31 is formed in the cutout portion of the second lens L4. The cut surface 35 is a plane that is non-parallel and non-perpendicular to the second optical axis O2, and is inclined so as to increase the radial distance from the second optical axis O2 as it proceeds from the incident surface 30 to the exit surface 31. doing.

  The first lens L3 and the second lens L4 have substantially the same radial size from the second optical axis O2 to the outer peripheral surface 22c and the outer peripheral surface 32c. The cut surface 25 of the first lens L3 and the cut surface 35 of the second lens L4 are formed in substantially the same range in the radial direction with the second optical axis O2 as the center.

  As shown in FIGS. 3 and 4, the second group frame 13 is formed with a holding hole 40 through which the first lens L3 and the second lens L4 are inserted in the optical axis direction. The second group frame 13 forms a holding hole 40, and a first frame portion 41 that surrounds the outer peripheral surface 22c of the annular peripheral portion 22 of the first lens L3 and the outer peripheral surface 32c of the annular peripheral portion 32 of the second lens L4. And a second frame portion 42 surrounding the cut surface 25 of the first lens L3 and the cut surface 35 of the second lens L4.

  As shown in FIG. 2 and FIG. 3, a side protrusion 43 and a side protrusion 44 that protrude from the first frame portion 41 to one side and the other side in the width direction are provided. A guide hole 45 penetrating in the optical axis direction is formed in the side protrusion 43, and the first guide shaft 16 (FIG. 1) fixedly supported in the housing 12 is inserted into the guide hole 45. A rotation restricting hole 46 penetrating in the optical axis direction is formed in the side protrusion 44, and a second guide shaft (not shown) fixedly supported in the housing 12 is inserted into the rotation restricting hole 46. . Both the first guide shaft 16 and the second guide shaft are oriented in the optical axis direction, and the second group frame 13 can move in the optical axis direction when the guide hole 45 is guided by the first guide shaft 16. Supported by The rotation of the second group frame 13 around the first guide shaft 16 is restricted by the second guide shaft and the rotation restriction hole 46.

  A lead screw 17 (FIG. 1) extending in parallel with the first guide shaft 16 is supported in the housing 12, and a nut (not shown) that engages with the lead screw 17 is a nut receiving portion 47 of the side protrusion 43. Is fitted. The lead screw 17 is rotationally driven by a motor (not shown) supported by the housing 12, and the nut moves in the optical axis direction by the rotation of the lead screw 17. A force is transmitted from the nut to the nut receiving portion 47, and the second group frame 13 moves in the optical axis direction. Although not shown in detail, the third group frame 14 is moved in the optical axis direction by the same drive mechanism as that of the second group frame 13. The imaging optical system of the imaging apparatus 10 has a variable focal length, and zooming (magnification) is performed by moving the second group G2 supported by the second group frame 13 and the third group G3 supported by the third group frame 14 in the optical axis direction. Operation is performed.

  As shown in FIGS. 2 to 4, in the second group frame 13, the inner shape of the holding hole 40 is different between the first frame portion 41 and the second frame portion 42. The inner surface of the holding hole 40 in the first frame portion 41 has a cylindrical surface 50 on the incident side, a cylindrical surface 51 on the exit side, and a regulation surface (incident side positioning portion) following the cylindrical surface 50. 52 is formed, and a regulating surface (ejecting side positioning portion) 53 is formed following the cylindrical surface 51. Both the cylindrical surface 50 and the cylindrical surface 51 are part of a cylindrical inner peripheral surface centered on the second optical axis O2, and the cylindrical surface 50 in the radial direction centered on the second optical axis O2 The inner diameter size of the cylindrical surface 51 is substantially equal. The regulation surface 52 and the regulation surface 53 are both planes substantially perpendicular to the second optical axis O2, with the regulation surface 52 facing the incident side and the regulation surface 53 facing the exit side. An intermediate protrusion 54 that protrudes toward the second optical axis O2 is formed at a position in the optical axis direction between the restriction surface 52 and the restriction surface 53.

  As shown in FIG. 3, on the incident side of the first frame portion 41, a plurality (four) of recesses 55 are formed at different positions in the circumferential direction around the second optical axis O2. Each recess 55 is recessed from the cylindrical surface 50 in the outer diameter direction (the direction away from the second optical axis O2), and is open to the end surface on the incident side of the first frame portion 41. In addition, two positioning protrusions 56 project from the end face on the incident side of the first frame portion 41.

  On the emission side of the first frame portion 41, a plurality of recesses 57 (partially shown in FIGS. 2 and 3) similar to the recesses 55 are provided. Each recess 57 is recessed from the cylindrical surface 51 toward the outer diameter direction, and is open to the end surface on the emission side of the first frame portion 41. Similarly to the positioning projection 56, two positioning projections 58 (one in each of FIGS. 1 and 2) are provided on the end face on the emission side of the first frame portion 41.

  As shown in FIGS. 1 to 4, the frame inner surface portion 60, which is the inner surface of the holding hole 40 in the second frame portion 42, has an inclined inner surface (incident side region, incident side inclined inner surface) 61 on the incident side. An inclined inner surface (an emission side region, an emission side inclined inner surface) 62 is provided on the side. The inclined inner surface 61 is a plane that decreases the radial distance from the second optical axis O2 as it proceeds from the incident side toward the emission side, and the inclined inner surface 62 is the second as it proceeds from the incident side toward the emission side. It is a plane that increases the radial distance from the optical axis O2. That is, the frame inner surface portion 60 has a substantially chevron shape in which the distance in the radial direction from the second optical axis O2 is smaller at the intermediate portion than at the end portions on the incident side and the emission side in the optical axis direction. The outer surface part located in the back side of the frame inner surface part 60 among the 2nd frame parts 42 is a planar shape substantially parallel to the 2nd optical axis O2. Therefore, the second frame portion 42 has a substantially chevron-shaped cross-sectional shape that gradually increases in thickness from the incident side and the emission side in the optical axis direction toward the intermediate portion depending on the shape of the frame inner surface portion 60 (FIG. 4). reference). The inclination angle of the inclined inner surface 61 with respect to the second optical axis O2 is substantially the same as that of the cut surface 25 of the first lens L3, and the inclination angle of the inclined inner surface 62 with respect to the second optical axis O2 is the cut surface 35 of the second lens L4. Is almost the same. That is, the inclined inner surface 61 is a plane substantially parallel to the cut surface 25, and the inclined inner surface 62 is a plane substantially parallel to the cut surface 35. An intermediate protrusion 63 that protrudes toward the second optical axis O <b> 2 is formed at a position in the optical axis direction between the inclined inner surface 61 and the inclined inner surface 62.

  As shown in FIGS. 2 and 4, the first lens L <b> 3 has a circumferential position centered on the second optical axis O <b> 2 so that the position of the cut surface 25 corresponds to the second frame portion 42, and the incident surface. 20 is directed to the incident side and the exit surface 21 is directed to the exit side (the direction of the first lens L3 in the optical axis direction is referred to as a first direction), and is inserted into the holding hole 40 from the incident side to form the second group frame. 13 is assembled. At this time, if the first lens L3 is in the direction opposite to the first direction in the optical axis direction (the incident surface 20 faces the exit side and the exit surface 21 faces the entrance side), the cut surface with respect to the second optical axis O2 25 and the inclined inner surface 61 are opposite to each other, and the boundary between the cut surface 25 and the incident surface 20 abuts on and interferes with the inclined inner surface 61, so that the insertion of the first lens L3 into the holding hole 40 is restricted. The A virtual first lens L3x which is opposite to the first direction is indicated by a one-dot chain line in FIG. The virtual cut surface 25x shown in FIG. 5 has an optical axis direction forming range and a radial direction forming range substantially the same as the cut surface 25, and the inclined direction with respect to the second optical axis O2 is an inclined surface opposite to the cut surface 25. is there. The cut surface 25x intersects the inclined inner surface 61 of the second group frame 13, and the first lens L3x cannot be inserted up to the position shown in FIG.

  Further, when the first lens L3 is inserted in the first direction with respect to the holding hole 40 from the exit side, the boundary portion between the cut surface 25 and the entrance surface 20 abuts against the inclined inner surface 62 and interferes therewith. The insertion of the first lens L3 from the side is restricted.

  The position of the first lens L3 inserted in the holding hole 40 from the incident side in the first direction is determined by the reference surface 22b coming into contact with the regulating surface 52 (see FIG. 4). In this state, there are clearances between the cut surface 25 and the inclined inner surface 61, and between the outer peripheral surface 22c of the annular peripheral edge 22 and the cylindrical surface 50, and the first lens L3 is orthogonal to the second optical axis O2. Position adjustment (alignment) in a plane can be performed. The alignment operation can be performed by inserting an instrument into the recess 55. When the alignment of the first lens L3 is completed, the concave portion 55 is filled with an adhesive, and the first lens L3 is fixed to the second group frame 13.

  With the first lens L 3 fixed in the holding hole 40, the incident side light shielding frame (incident side light shielding member) 70 is attached to the second group frame 13. As shown in FIG. 2, the incident-side light shielding frame 70 is a plate-like member that covers the incident-side surfaces of the first frame portion 41 and the second frame portion 42, and has a D-shaped optical path opening that penetrates in the optical axis direction. 71. The inner edge portion of the incident-side light shielding frame 70 facing the optical path opening 71 is a circular circular edge portion 72 centering on the second optical axis O2 in a portion corresponding to the first frame portion 41, and corresponds to the second frame portion 42. In the part, it becomes the linear edge part 73 extended in the width direction.

  The incident-side light shielding frame 70 has a positioning groove 74 and a positioning groove 75 on one side and the other side in the width direction across the optical path opening 71. By inserting the positioning projections 56 into the positioning grooves 74 and 75, the attachment position of the incident side light shielding frame 70 to the second group frame 13 is determined. The incident-side light shielding frame 70 is fixed to the second group frame 13 by means such as adhesion. As shown in FIG. 4, the incident-side light shielding frame 70 attached to the second group frame 13 is positioned on the incident side of the peripheral edge of the first lens L <b> 3 including the annular peripheral edge 22 and the cut surface 25. The incidence of light on the periphery of the lens L3 is blocked. In particular, a portion of the incident-side light shielding frame 70 along the straight edge portion 73 is located in a region on the incident side with respect to the cut surface 25, and a part of the light traveling toward the cut surface 25 can be blocked.

  As shown in FIGS. 2 and 4, the second lens L <b> 4 is aligned with the circumferential position around the second optical axis O <b> 2 so that the position of the cut surface 35 corresponds to the second frame portion 42, and the incident surface. The second group frame is inserted into the holding hole 40 from the exit side, with 30 facing the entrance side and the exit surface 31 facing the exit side (the direction of the optical axis direction of the second lens L4 is referred to as the second orientation). 13 is assembled. At this time, if the second lens L4 is opposite to the second direction in the optical axis direction (the incident surface 30 faces the exit side and the exit surface 31 faces the incident side), the cut surface with respect to the second optical axis O2 35 and the inclined inner surface 62 are inclined in directions opposite to each other, and the boundary portion between the cut surface 35 and the emission surface 31 abuts on and interferes with the inclined inner surface 62, so that the insertion of the second lens L4 into the holding hole 40 is restricted. The A virtual second lens L4x that is opposite to the second direction is indicated by a one-dot chain line in FIG. The virtual cut surface 35x shown in FIG. 5 has an optical axis direction forming range and a radial direction forming range substantially the same as the cut surface 35, and the inclined direction with respect to the second optical axis O2 is an inclined surface opposite to the cut surface 35. is there. The cut surface 35x intersects the inclined inner surface 62 of the second group frame 13, and the second lens L4x cannot be inserted to the holding hole 40 of the second group frame 13 up to the position shown in FIG.

  Further, if the second lens L4 is inserted in the second direction with respect to the holding hole 40 from the incident side, the boundary portion between the cut surface 35 and the exit surface 31 abuts against the inclined inner surface 61 and interferes therewith. The insertion of the second lens L4 from the side is restricted.

  The position of the second lens L4 inserted in the holding hole 40 from the exit side in the second direction is determined by the reference surface 32a coming into contact with the regulating surface 53 (see FIG. 4). In this state, there are clearances between the cut surface 35 and the inclined inner surface 62, between the outer peripheral surface 32c of the annular peripheral edge portion 32 and the cylindrical surface 51, and between the step portion 33 and the central protruding portion 54, respectively. The two lenses L4 can perform position adjustment (alignment) in a plane orthogonal to the second optical axis O2. The alignment operation can be performed by inserting an instrument into the recess 57. When the alignment of the second lens L4 is completed, the concave portion 57 is filled with an adhesive, and the second lens L4 is fixed to the second group frame 13.

  In the state where the second lens L4 is fixed in the holding hole 40, the diaphragm frame (emitted light shielding member) 80 is attached to the second group frame 13. As shown in FIG. 2, the diaphragm frame 80 is a plate-like member that covers the emission side surfaces of the first frame portion 41 and the second frame portion 42, and has a D-shaped optical path opening 81 penetrating in the optical axis direction. Have. The inner edge portion of the diaphragm frame 80 facing the optical path opening 81 is a circular circular edge portion 82 centered on the second optical axis O2 in the portion corresponding to the first frame portion 41, and in the portion corresponding to the second frame portion 42. The straight edge 83 extends in the width direction.

  The aperture frame 80 has a positioning groove 84 and a positioning hole 85 on one side and the other side in the width direction across the optical path opening 81. One positioning projection 58 is sandwiched by the positioning groove 84 and the other positioning projection 58 is inserted into the positioning hole 85 to determine the attachment position of the diaphragm frame 80 to the second group frame 13. The diaphragm frame 80 is fixed to the second group frame 13 by means such as adhesion. As shown in FIG. 4, the diaphragm frame 80 attached to the second group frame 13 is located on the exit side of the peripheral edge of the second lens L4 including the annular peripheral edge 32 and the cut surface 35, and the second lens L4. The light which tries to advance to the 3rd group G3 from the peripheral part of is blocked | interrupted. In particular, the portion of the diaphragm frame 80 along the straight edge 83 is located in the region on the emission side with respect to the cut surface 35 and blocks part of the light reflected by the cut surface 35 and traveling toward the imaging surface. be able to.

  As described above, in the state where the first lens L3 and the second lens L4 are assembled to the second group frame 13 from the opposite sides of the optical axis direction, the positions in the optical axis direction of the first lens L3 and the second lens L4, and the exit surface The distance between the optical axis 21 and the incident surface 30 in the optical axis direction is determined with reference to the regulation surface 52 and the regulation surface 53 in the holding hole 40 of the second group frame 13, and the second group lens unit 15 including the second group G2 is configured.

  The cut surface 25 of the first lens L3 and the cut surface 35 of the second lens L4 in the second group G2 have a structure that makes it difficult for harmful reflected light to reach the imaging surface (the light receiving surface of the imaging sensor 11). Details will be described with reference to the lens unit 15 ′ of the comparative example shown in FIG. 7. In addition, the part which uses the code | symbol common in FIG. 4 and FIG. 7 shall have a common structure (a shape and magnitude | size of a member).

  The lens unit 15 ′ of the comparative example of FIG. 7 has a cut surface 25 ′ of the first lens L3 ′ and a cut surface 35 ′ of the second lens L4 ′ that are planes substantially parallel to the second optical axis O2. Correspondingly, the frame inner surface portion 60 ′ of the holding hole 40 ′ of the second group frame 13 ′ is also different from the frame inner surface portion 60 of the holding hole 40 of the second group frame 13 of FIG. More specifically, the end position on the incident side of the cut surface 25 of the embodiment shown in FIG. 4 (the portion of the cut surface 25 having the largest distance from the second optical axis O2) is substantially parallel to the second optical axis O2. A cut surface 25 ′ in FIG. 7 is extended toward the injection side. Further, the end position on the exit side of the cut surface 35 of the embodiment shown in FIG. 4 (the portion of the cut surface 35 having the largest distance from the second optical axis O2) is incident substantially parallel to the second optical axis O2. A cut surface 35 ′ in FIG. 7 is extended toward the side. An optical axis parallel inner surface 61 ′ that is a plane substantially parallel to the second optical axis O2 is formed on the frame inner surface portion 60 ′ of the second group frame 13 ′ at a position facing the cut surface 25 ′, and the cut surface 35 ′. An optical axis parallel inner surface 62 ′, which is a plane substantially parallel to the second optical axis O2, is formed at a position opposite to. An intermediate protrusion 63 'is provided between the optical axis parallel inner surface 61' and the optical axis parallel inner surface 62 '. The distance from the tip of the intermediate protrusion 63 'to the second optical axis O2 is substantially equal to the distance from the tip of the intermediate protrusion 63 to the second optical axis O2 in the embodiment shown in FIG.

  FIG. 7 shows a light ray K11 that passes through the vicinity of the straight edge 73 and is directed to the cut surface 25 'of the first lens L3' without being blocked by the incident-side light shielding frame 70 in the lens unit 15 'of FIG. The light ray K11 is reflected by the cut surface 25 ′ and changes its direction so as to approach the second optical axis O2, exits from the exit surface 21 of the first lens L3 ′, passes through the vicinity of the intermediate protrusion 63 ′, and passes through the second. The light enters the entrance surface 30 of the lens L4 ′, exits from the exit surface 31 of the second lens L4 ′, and proceeds toward the third group G3. FIG. 7 shows a light ray K12 that passes through the vicinity of the intermediate protrusion 63 'and is directed to the cut surface 35' of the second lens L4 'without being blocked by the incident-side light shielding frame 70. The light ray K12 is reflected by the cut surface 35 ′ and changes its direction so as to approach the second optical axis O2, exits from the exit surface 31 of the second lens L4 ′, and is not blocked by the diaphragm frame 80, but is a straight edge. Proceed toward the third group G3 through 83. When the light beam reflected by the cut surface 25 ′ or the cut surface 35 ′ reaches the light receiving surface of the image sensor 11, flare or ghost may occur in the image.

  In the second group lens unit 15 of the embodiment shown in FIG. 4, in the first lens L <b> 3, the cut surface 25 is set as an inclined surface that approaches the second optical axis O <b> 2 as it proceeds from the incident side to the exit side. The incident light on the exit surface 21 is larger than the reflected light reflected by the cut surface 25 ′ of FIG. Then, when the light beam K1 having the same condition as the light beam K11 in FIG. 7 is incident on the first lens L3, the light beam reflected by the cut surface 25 of the first lens L3 is totally reflected by the exit surface 21. The inclination angle of the surface 25 is set.

  Further, in the second lens L4, the cut surface 35 is set as an inclined surface that moves away from the second optical axis O2 as it proceeds from the incident side to the emission side, so that the reflected light reflected by the cut surface 35 is cut as shown in FIG. The incident angle on the exit surface 31 is smaller than the reflected light reflected by the surface 35 ′. Then, when the light ray K2 having the same condition as the light ray K12 in FIG. 7 is incident on the second lens L4, the cut surface so that the light beam reflected by the cut surface 35 of the second lens L4 is blocked by the diaphragm frame 80. An inclination angle of 35 is set.

  As described above, in the second group lens unit 15 of the present embodiment, the cut surface 25 of the first lens L3 is provided with an inclination having a rising angle toward the incident side, and the rising angle toward the exit side is applied to the cut surface 35 of the second lens L4. By providing an inclination having the following, the reflected light on the cut surface 25 and the cut surface 35 does not easily reach the imaging surface (the light receiving surface of the imaging sensor 11), and the reflection on the cut surface 25 and the cut surface 35 is caused. Flares and ghosts can be effectively prevented. Therefore, the removal amount of the peripheral portions of the first lens L3 and the second lens L4 is increased within a range in which the effective diameter is ensured (the distance between the cut surface 25 and the cut surface 35 from the second optical axis O2 is decreased). The second group G2 and the second group frame 13 in the front-rear direction of the imaging device 10 can be reduced in size.

  In the form of FIG. 4, the diaphragm frame 80 is provided in the second group lens unit 15 to block the reflected light from the cut surface 35. However, even in the configuration without the diaphragm frame 80, the cut in the comparative example of FIG. As compared with the surface 35 ′, the flare and ghost suppression effect due to the inclination of the cut surface 35 can be obtained. Further, even in the configuration not including the incident-side light shielding frame 70, it is possible to obtain a flare and ghost suppression effect due to the inclination of the cut surface 25 as compared with the cut surface 25 'in the comparative example of FIG. For example, instead of the incident-side light shielding frame 70 and the diaphragm frame 80, a light shielding member may be disposed between the second group frame 13 and the third group frame 14, or a light shielding member may be attached to the third group frame 14. .

  The second frame portion 42 of the second group frame 13 has an inclined inner surface 61 and an inclined inner surface 62 corresponding to the inclined shapes of the cut surface 25 of the first lens L3 and the cut surface 35 of the second lens L4 in the frame inner surface portion 60. It has a mountain-shaped cross-sectional shape, and is thicker than the second frame portion 42 ′ of the second group frame 13 ′ of the comparative example shown in FIG. Therefore, the strength of the second frame portion 42 can be increased by increasing the thickness of the second frame portion 42 without increasing the size of the second group frame 13 in the front-rear direction. Further, by increasing the thickness of the second frame portion 42, when the second group frame 13 is formed of a resin or the like, weld lines are less likely to occur, and the quality and appearance of the second group frame 13 are improved. Each of the first frame portion 41 and the second frame portion 42 of the second group frame 13 has a shape that can be easily produced by a mold that is released in the optical axis direction, and the manufacturing cost can be reduced.

  In addition, since the assembling direction of the first lens L3 and the second lens L4 with respect to the second group frame 13 is determined by the cut surfaces 25 and 35 and the inclined inner surfaces 61 and 62, there is no risk of assembling the lenses L3 and L4 in the wrong direction. Contributes to improved productivity. For example, in the comparative example of FIG. 7, the cut surface 25 ′ and the optical axis parallel inner surface 61 ′ are substantially parallel even if the front and back of the first lens L <b> 3 ′ (the direction of the incident surface 20 and the exit surface 21) are reversed. Will not change. Further, even if the front and back surfaces of the second lens L4 'are reversed (the directions of the incident surface 30 and the exit surface 31), the relationship that the cut surface 35' and the optical axis parallel inner surface 62 'are substantially parallel does not change. Therefore, the first lens L 3 ′ is inserted into the holding hole 40 ′ of the second group frame 13 ′ in the direction in which the incident peripheral surface 22 a is in contact with the restriction surface 52, or the emission peripheral surface 32 b is in contact with the restriction surface 53. Incorrect orientation may cause insertion of the second lens L4 ′ into the holding hole 40 ′ of the second group frame 13 ′. On the other hand, as shown in FIG. 5, in the second group lens unit 15 of the present embodiment, the first lens L3x in a state opposite to the first direction is inserted from the incident side, or the second direction is set. Can prevent erroneous insertion of the second lens L4x in the opposite direction from the exit side.

  As described above, the second group lens unit 15 includes a cut surface in which the first lens L3 located on the incident side and the second lens L4 located on the exit side are inclined in a predetermined direction with respect to the second optical axis O2. The first lens L3 and the second lens L4 are reduced in size by having the cut surfaces 25 and 35 close to the second optical axis O2 while suppressing deterioration in image quality due to reflected light. Can be achieved. Further, the second frame portion 42 surrounding the cut surface 25 and the cut surface 35 in the second group frame 13 corresponds to each of the cut surfaces 25 and 35 and is in the radial direction from the second optical axis O2 at the intermediate portion in the optical axis direction. The inner surface portion 60 of the substantially chevron-shaped frame is reduced, and the thickness of the second frame portion 42 can be increased without increasing the size of the second group frame 13, thereby ensuring the strength. Therefore, it is possible to make the second lens unit 15 small and excellent in optical performance and strength. The second group lens unit 15 is also excellent in productivity such as ease of assembly work.

  The second group lens unit 115 shown in FIG. 6 is an embodiment in which the shape of the frame inner surface portion 160 of the second frame portion 42 is different. The frame inner surface portion 160 includes a stepped inner surface (incident side region) 161 facing the cut surface 25 of the first lens L3, a stepped inner surface (exit side region) 162 facing the cut surface 35 of the second lens L4, An intermediate protrusion 163 is provided between the stepped inner surface 161 and the stepped inner surface 162 in the optical axis direction and protrudes toward the second optical axis O2. As shown in an enlarged view in FIG. 6, the stepped inner surface 161 decreases the distance in the radial direction from the second optical axis O2 as it proceeds from the incident side toward the exit side (the inclined inner surface 61 of the previous embodiment). The optical axis parallel surface portion 161b that is a plane substantially parallel to the second optical axis O2 is formed in the middle of the inclined surface portion 161a that is a flat surface (having the same inclination as the above). The stepped inner surface 162 is an inclined plane that has a radial distance from the second optical axis O2 that increases from the incident side toward the emission side (having the same inclination as the inclined inner surface 62 of the previous embodiment). In this configuration, an optical axis parallel surface portion 162b that is a plane substantially parallel to the second optical axis O2 is formed in the middle of the surface portion 162a. The intermediate protrusion 163 has substantially the same shape as the intermediate protrusion 63 in the second group lens unit 15 of FIG.

  Each of the stepped inner surface 161 and the stepped inner surface 162 has a flat portion in the middle substantially parallel to the second optical axis O2, but the frame inner surface portion 160 as a whole is from the respective end portions on the incident side and the emission side. In the middle part, the distance from the second optical axis O2 in the radial direction is a small mountain shape. Therefore, the frame inner surface portion 160 allows the first lens L3 to be inserted into the holding hole 40 from the incident side in the first direction, like the frame inner surface portion 60 in the second group lens unit 15 of FIG. It is restricted that the lens L3 is inserted from the incident side in the opposite direction to the first direction, and that the first lens L3 is inserted from the emission side in the first direction. In addition, the frame inner surface portion 160 allows the second lens L4 to be inserted into the holding hole 40 from the exit side in the second direction, while inserting the second lens L4 from the exit side in the direction opposite to the second direction. And the insertion of the second lens L4 in the second direction from the incident side is restricted. And the thickness of the 2nd frame part 42 of the 2nd group frame 13 can be enlarged by the substantially chevron shape of the frame inner surface part 160, and intensity | strength can be ensured. That is, the inner surface shape of the second frame portion 42 of the second group frame 13 is not necessarily a planar shape that is completely parallel to the cut surface 25 of the first lens L3 and the cut surface 35 of the second lens L4. However, the stepped inner surface 161 and the stepped inner surface 162 of the frame inner surface portion 160 are compared with the inclined inner surface 61 and the inclined inner surface 62 of the frame inner surface portion 60 of FIG. 4 in a plane portion substantially parallel to the second optical axis O2. Since the thickness is reduced, the frame inner surface portion 60 in FIG. 4 is an advantageous form for securing the strength.

  As mentioned above, although demonstrated based on illustration embodiment, this invention is not limited to these embodiment, Various forms can be employ | adopted within the range of a summary. For example, in the second group lens units 15 and 115 of the embodiment, the two lenses of the first lens L3 and the second lens L4 are held in the second group frame 13, but three or more lenses are shared by a common lens frame. The present invention is also applicable to a lens unit that is held inside. Specifically, a configuration in which another lens is disposed at the position in the optical axis direction between the first lens L3 and the second lens L4, or an incident side from the first lens L3 or an exit side from the second lens L4. It is also possible to adopt a form in which these lenses are arranged. In the latter form, the position of the other lens in the optical axis direction is determined by abutting against the incident peripheral surface 22a of the first lens L3 or the exit peripheral surface 32b of the second lens L4, or the incident peripheral surface 22a or the exit surface. The position of another lens in the optical axis direction can be determined by interposing a spacing member (spacer) between the peripheral surface 32b.

  In the second group lens units 15 and 115 of the embodiment, the incident side lens is a first lens L3 having a biconvex lens, and the exit side lens is a second lens L4 having a concave meniscus lens. The shape of the lens and the exit side lens is not limited to this. Further, not a single lens but also a bonded lens can be applied as an entrance side lens and an exit side lens.

  In the embodiment, the sizes in the radial direction around the second optical axis O2 (radial positions of the outer peripheral surface 22c and the outer peripheral surface 32c and radial positions of the cut surface 25 and the cut surface 35) are substantially the same. The first lens L3 and the second lens L4 are held in the second group frame 13. According to this configuration, the second group lens units 15 and 115 that can be accommodated in the housing 12 of the imaging device 10 with good space efficiency by reducing the unevenness of the outer surface shape of the first frame portion 41 and the second frame portion 42 of the second group frame 13. Can be. However, the present invention can also be applied to lens units of a type in which the incident side lens and the emission side lens have different radial sizes.

  Each of the first lens L3 and the second lens L4 in the embodiment is a so-called D-cut lens having a cut-out shape with the cut surfaces 25 and 35 only at one place in the circumferential direction. In addition, the exit side lens can arbitrarily set the number of inclined surfaces (cut surfaces) in the circumferential direction. For example, an oval lens having two inclined surfaces (cut surfaces) in a substantially symmetrical relationship with respect to the optical axis, or a lens having three or more inclined surfaces (cut surfaces) with different positions in the circumferential direction is adopted. You can also

  In the second group lens units 15 and 115 of the embodiment, the first lens L3 and the second lens L4 are bonded and fixed to the second group frame 13 after alignment, but in the present invention, on the incident side with respect to the lens frame. The means for fixing the lens and the exit side lens is not limited to adhesion, and any fixing means or fixing structure can be adopted.

  The second group lens units 15 and 115 of the embodiment are located on the second optical axis O2 of the bending optical system in the imaging apparatus 10, but the lens unit that constitutes an optical system that is not such a bending optical system is also used. The present invention can be applied. In addition, the second group lens units 15 and 115 of the embodiment are movable in the optical axis direction, but the present invention can also be applied to lens units that are not movable. Furthermore, the present invention is applicable to lens units other than the second group G2 in the optical system.

DESCRIPTION OF SYMBOLS 10 Imaging device 11 Imaging sensor 12 Housing 13 2 group frame (lens frame)
14 3rd group frame 15 2nd group lens unit 16 1st guide shaft 17 Lead screw 20 Incident surface 21 Ejection surface 22 Annular peripheral part 22a Incident peripheral surface 22b Reference surface (1st reference surface)
22c outer peripheral surface (first outer peripheral surface)
25 Cut surface (first inclined surface)
30 entrance surface 31 exit surface 32 annular peripheral edge 32a reference surface (second reference surface)
32b Injection peripheral surface 32c Outer peripheral surface (second outer peripheral surface)
35 Cut surface (second inclined surface)
33 Step portion 40 Holding hole 41 First frame portion 42 Second frame portion 43 44 Side protrusion 45 Guide hole 46 Rotation restriction hole 47 Nut receiving portion 50 51 Tubular surface 52 Restriction surface (incident side positioning portion)
53 Restriction surface (Injection side positioning part)
54 intermediate protrusion 55 57 recess 56 58 positioning projection 60 frame inner surface 61 inclined inner surface (incident side region, incident side inclined inner surface)
62 Inclined inner surface (Ejection side area, Ejection side inclined inner surface)
63 Intermediate protrusion 70 Incident side light shielding frame (incident side light shielding member)
71 Optical path opening 72 Circular edge 73 Linear edge 74 75 Positioning groove 80 Diaphragm frame (emitted light shielding member)
81 optical path opening 82 circular edge 83 linear edge 84 positioning groove 85 positioning hole 115 second group lens unit 160 frame inner surface 161 stepped inner surface (incident side region)
162 Stepped inner surface (injection side area)
161a 162a Inclined surface portion 161b 162b Optical axis direction plane portion 163 Intermediate protrusion G1 First group G2 Second group G3 Third group G4 Fourth group L1 First lens L2 Second lens L3 First lens (incident side lens)
L4 Second lens (exit side lens)
O1 First optical axis O2 Second optical axis (optical axis)
O3 Third optical axis PR1 First prism PR2 Second prism

Claims (9)

An incident side lens located on the incident side in the optical axis direction and an exit side lens located on the exit side;
A first outer peripheral surface having a cylindrical shape centered on the optical axis, provided at a peripheral edge in the radial direction centered on the optical axis in the incident side lens, and the first outer peripheral surface in the radial direction than the first outer peripheral surface. A planar first inclined surface having a small distance from the optical axis and decreasing the radial distance from the optical axis as it proceeds from the incident side to the exit side in the optical axis direction;
A second outer peripheral surface having a cylindrical shape centered on the optical axis, provided on a peripheral edge in the radial direction centered on the optical axis in the emission side lens, and the second outer peripheral surface in the radial direction than the second outer peripheral surface. A planar second inclined surface having a small distance from the optical axis and increasing the radial distance from the optical axis as it proceeds from the incident side to the exit side in the optical axis direction;
A first frame portion having a holding hole for inserting at least the entrance side lens and the exit side lens therein, surrounding the first outer peripheral surface and the second outer peripheral surface, and the first inclined surface And a lens frame having a second frame portion surrounding the outside of the second inclined surface;
An incident-side positioning unit that determines the position of the incident-side lens in the optical axis direction, and an emission-side positioning unit that determines the position of the emission-side lens in the optical axis direction; The inner surface of the holding hole is configured by the second frame portion, and is positioned by the incident side region along the first inclined surface of the incident side lens positioned by the incident side positioning portion, and positioned by the emission side positioning portion. An exit-side region along the second inclined surface of the exit-side lens, and the entrance-side region is a distance in the radial direction from the optical axis at the exit side than the entrance side in the optical axis direction. The inner surface of the frame having a smaller distance from the optical axis on the exit side than on the incident side in the optical axis direction.
A lens unit comprising: The lens unit according to claim 1, wherein
The incident side region of the inner surface of the frame has a virtual range in which the formation range in the optical axis direction and the radial direction is the same as the first inclined surface, and the inclined direction with respect to the optical axis is opposite to the first inclined surface. It intersects with the inclined surface,
The emission side region of the inner surface of the frame has a virtual range in which the optical axis direction and the radial direction are formed in the same range as the second inclined surface, and the inclined direction with respect to the optical axis is opposite to the second inclined surface. A lens unit that intersects the inclined surface.   3. The lens unit according to claim 1, wherein the incident side region of the inner surface portion of the frame has a planar shape substantially parallel to the first inclined surface of the incident side lens, and the emission of the inner surface portion of the frame. The side region is a lens unit having a planar shape substantially parallel to the second inclined surface of the emission side lens. An incident side lens located on the incident side in the optical axis direction and an exit side lens located on the exit side;
A first outer peripheral surface having a cylindrical shape centered on the optical axis, provided at a peripheral edge in the radial direction centered on the optical axis in the incident side lens, and the first outer peripheral surface in the radial direction than the first outer peripheral surface. A flat first inclined surface having a small distance from the optical axis and non-parallel and non-perpendicular to the optical axis;
A second outer peripheral surface having a cylindrical shape centered on the optical axis, provided on a peripheral edge in the radial direction centered on the optical axis in the emission side lens, and the second outer peripheral surface in the radial direction than the second outer peripheral surface. A planar second inclined surface having a small distance from the optical axis and non-parallel and non-perpendicular to the optical axis;
A first frame portion having a holding hole for inserting at least the entrance side lens and the exit side lens therein, surrounding the first outer peripheral surface and the second outer peripheral surface, and the first inclined surface And a lens frame having a second frame portion surrounding the outside of the second inclined surface;
An incident-side positioning unit that determines the position of the incident-side lens in the optical axis direction, and an emission-side positioning unit that determines the position of the emission-side lens in the optical axis direction; The inner surface of the holding hole is configured by the second frame portion, and the inner surface of the frame is smaller in the radial direction from the optical axis at the intermediate portion than the respective end portions on the incident side and the emission side in the optical axis direction. Part;
Have
The incident side lens has a first orientation that reduces the radial distance from the optical axis as the first inclined surface advances from the incident side to the exit side in the optical axis direction. The frame inner surface portion is held in the holding hole, and the frame inner surface portion has the first lens from the incident side into the holding hole when the incident side lens is opposite to the first direction in the optical axis direction. And the exit side lens has a radial distance from the optical axis as the second inclined surface advances from the entrance side to the exit side in the optical axis direction. The lens frame is held in the holding hole of the lens frame in a second direction to be enlarged, and the inner surface of the frame is emitted when the emission side lens is opposite to the second direction in the optical axis direction. Restricting insertion of the second inclined surface into the holding hole from the side To do;
Lens unit characterized by   5. The lens unit according to claim 4, wherein the frame inner surface portion restricts insertion of the first inclined surface from the exit side into the holding hole when the incident side lens is in the first direction. A lens unit for restricting insertion of the second inclined surface from the incident side into the holding hole when the exit side lens is in the second direction. The lens unit according to claim 4 or 5, wherein the inner surface of the frame is
A planar incident-side inclined inner surface facing the first inclined surface in a state where the incident-side lens is positioned in the optical axis direction by the incident-side positioning portion; and substantially parallel to the first inclined surface; A flat exit-side inclined inner surface that is substantially parallel to the second inclined surface and faces the second inclined surface in a state where the exit-side lens is positioned in the optical axis direction by the exit-side positioning unit;
A lens unit. The lens unit according to any one of claims 1 to 6,
The incident-side positioning portion is a flat surface that is substantially perpendicular to the optical axis and faces the incident side in the optical axis direction, and the incident-side lens is in contact with the incident-side positioning portion from the incident side. A first reference plane whose position in the direction is determined,
The exit side positioning portion is a plane that is substantially perpendicular to the optical axis and faces the exit side in the optical axis direction, and the exit side lens contacts the exit side positioning portion from the exit side to the optical axis. A lens unit having a second reference surface whose position in the direction is determined.   The lens unit according to any one of claims 1 to 7, wherein the lens unit is attached to the lens frame at a position closer to the exit side than the exit side lens in the optical axis direction, and is reflected by the second inclined surface. A lens unit having an exit-side light blocking member that blocks at least part of light traveling toward the exit side.   9. The lens unit according to claim 1, wherein the lens unit is attached to the lens frame at a position closer to the incident side than the incident side lens in the optical axis direction, and the first inclined surface from the incident side. A lens unit comprising an incident-side light blocking member that blocks at least a part of the light traveling toward.

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