Lens and lens unit

Abstract

To provide a resin lens capable of reducing tangential angle at an outer peripheral end of a concave lens surface.SOLUTION: A lens unit 10 comprises: a first lens 1; a second lens 2 adjacent to an image side X2 of the first lens 1; and a lens-barrel 7 holding the first lens 1 and the second lens 2. The first lens 1 is made of resin, and includes: a first object side lens surface 41 facing an object side X1; a first image side lens surface 42 facing an image side X2; and an image side flange face 43 surrounding the first image side lens surface 42 from outer peripheral side. The first image side lens surface 42 has a concave shape recessed toward the object side X1. The image side flange face 43 includes: an inclined surface 45 inclined to the image side X2 from the outer peripheral end of the first image side lens surface 42 toward the outer peripheral side; and a vertical surface 46 perpendicular to the optical axis L at the outer peripheral side of the inclined surface 45. The lens-barrel 7 includes a support part 23 supporting the vertical surface 46 from the image side X2.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a lens having a concave lens surface and a lens unit. [Background technology]

[0002] A lens unit having a first lens, a plurality of lenses arranged on the image side of the first lens, and a lens barrel that holds these lenses is described in Patent Document 1. In this document, the first lens has a first lens surface facing the object side, a second lens surface facing the image side, and a flange surface that surrounds the second image side lens surface from the outer periphery side. The first lens is a meniscus lens, and the first lens surface has a convex shape that protrudes toward the object side. The second lens surface has a concave shape that is recessed toward the object side. The flange surface is perpendicular to the optical axis of the first lens. A light shielding plate is attached to the flange surface. The lens barrel has a support portion that supports the flange surface of the first lens from the image side via the light shielding plate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2009-216774 A Summary of the Invention [Problem to be solved by the invention]

[0004] In a lens unit of a wide-angle optical system as described in Patent Document 1, a glass lens having a high refractive index is often used as the first lens. However, glass lenses are inferior in moldability and tend to be expensive to manufacture compared to resin lenses. Therefore, in addition to lens units designed on the premise of using a glass lens as the first lens, attempts have been made to add to the lineup lens units in which the first lens is replaced with a resin lens having a lower refractive index than glass.

[0005] When attempting to obtain the same optical characteristics as a glass lens using a resin lens, the difference in refractive index may cause the recess in the second lens surface of the lens to become deeper, causing the second lens surface to approach a hemispherical shape. In this case, the tangent angle at the outer circumferential edge of the second lens surface approaches a right angle. In other words, when the second lens surface approaches a hemispherical shape, the inclination of the tangent at the outer circumferential edge of the second lens surface approaches a state parallel to the optical axis.

[0006] Here, when the inclination of the tangent at the outer peripheral end of the second lens surface approaches a state parallel to the optical axis, the angle at which the flange surface perpendicular to the optical axis intersects with the second lens surface approaches a right angle. When the angle at which the second lens surface intersects with the flange surface approaches a right angle, it becomes difficult to separate the lens of the molded body from the mold during lens production, compared to when the angle at which the second lens surface intersects with the flange surface is smaller than the right angle. In addition, when the inclination of the tangent at the outer peripheral end of the second lens surface approaches a state parallel to the optical axis, it may be difficult to measure the shape of the second lens surface by contacting the probe with the second lens surface from the image side in the optical axis direction. That is, when the inclination of the tangent at the outer peripheral end of the second lens surface approaches a state parallel to the optical axis, when the tip of the contact portion of the conical probe is brought into contact with the outer peripheral end portion of the second lens surface, the base end side of the contact portion of the probe may interfere with the end of the second lens surface located on the object side of the measurement position, making the measurement difficult.

[0007] In view of the above problems, an object of the present invention is to provide a resin lens capable of reducing the tangent angle at the outer peripheral edge of the concave lens surface, and to provide a lens unit having such a lens. [Means for solving the problem]

[0008] In order to solve the above problems, the lens of the present invention has a first lens surface, a second lens surface facing opposite to the first lens, and a flange surface surrounding the second lens surface from an outer circumferential side, wherein the second lens surface has a concave shape recessed toward the first lens surface side, and the flange surface has an inclined surface portion that inclines from the outer circumferential end of the second lens surface toward the outer circumferential side in a direction away from the first lens surface, and a vertical surface portion on the outer circumferential side of the inclined surface portion that is perpendicular to the optical axis, and is made of resin.

[0009] According to the present invention, the flange surface surrounding the second lens surface from the outer periphery side includes an inclined surface portion inclined from the outer periphery end of the second lens surface toward the outer periphery side in a direction away from the first lens surface. Therefore, for example, compared with a case where the entire flange surface is made of a vertical surface perpendicular to the optical axis and the second lens surface is extended in the optical axis direction until it reaches the flange surface, the position of the outer periphery end of the second lens surface can be set at a position closer to the first lens surface. As a result, the tangent of the outer periphery end of the second lens surface inclines toward the optical axis toward the first lens side, so that the tangent angle of the outer periphery end can be made small. Therefore, during the manufacture of the lens, it becomes easy to release the lens of the molded body from the mold. In addition, the flange surface includes an inclined surface portion connected to the second lens surface. The inclined surface portion inclines from the outer periphery end of the second lens surface toward the outer periphery side in a direction away from the first lens surface. As a result, the angle at which the second lens surface and the flange surface intersect becomes large, so that it becomes easier to release the lens of the molded body from the mold. Furthermore, according to the present invention, the tangent angle of the outer peripheral edge of the second lens surface can be made small, so that it is easy to measure the shape of the second lens surface by contacting a probe with the second lens surface from the image side in the optical axis direction. That is, since the tangent angle of the outer peripheral edge of the second lens surface can be made small, it is possible to prevent the base end side of the contact portion of the probe from interfering with the edge of the second lens surface located on the object side of the measurement position when the tip of the contact portion of the conical probe is brought into contact with the outer peripheral edge portion of the second lens surface.

[0010] In the present invention, the tangent angle of the outer circumferential edge of the second lens surface may be equal to or less than 72°. This makes it easy to measure the second lens surface with a shape measuring machine that uses a probe to measure the shape of the lens surface.

[0011] In the present invention, the vertical surface portion and the inclined surface portion may be adjacent to each other in a radial direction, and the inclined surface portion may be smoothly continuous with the vertical surface portion.

[0012] Next, the present invention is a lens unit having a first lens, a second lens located adjacent to the image side of the first lens, and a barrel holding the first lens and the second lens, wherein the first lens is made of resin and has a first object side lens surface facing the object side, a first image side lens surface facing the image side, and an image side flange surface surrounding the first image side lens surface from an outer circumferential side, the first image side lens surface having a concave shape recessed toward the object side, the image side flange surface having an inclined surface portion that inclines toward the image side from the outer circumferential end of the first image side lens surface toward the outer circumferential side, and a vertical surface portion perpendicular to the optical axis on the outer circumferential side of the inclined surface portion, and the barrel has a support portion that supports the vertical surface portion from the image side.

[0013] According to the present invention, the image side flange surface surrounding the first image side lens surface from the outer periphery side includes an inclined surface portion that inclines from the outer periphery end of the first image side lens surface toward the image side from the outer periphery end of the first image side lens surface toward the outer periphery side. Therefore, for example, compared to a case in which the entire image side flange surface is made of a vertical surface perpendicular to the optical axis and the first image side lens surface is extended in the optical axis direction until it reaches the image side flange surface, the position of the outer periphery end of the first image side lens surface can be set at a position closer to the first object side lens surface. As a result, the tangent to the outer periphery end of the first image side lens surface inclines toward the optical axis toward the object side, so that the tangent angle of the outer periphery end can be made small. Therefore, when the lens of the molded body is separated from the mold during lens production, The image side flange surface includes an inclined surface portion connected to the first image side lens surface. The inclined surface portion is inclined from the outer peripheral end of the first image side lens surface toward the outer peripheral side in a direction away from the first object side lens surface. This increases the angle at which the first image side lens surface and the image side flange surface intersect, making it easier to separate the lens of the molded body from the mold. Furthermore, according to the present invention, the tangent angle of the outer peripheral end of the first image side lens surface can be reduced, making it easier to measure the shape of the first image side lens surface by contacting the probe with the first image side lens surface from the image side in the optical axis direction. That is, since the tangent angle of the outer peripheral end of the first image side lens surface can be reduced, it is possible to avoid the base end side of the contact portion of the probe interfering with the end of the first image side lens surface located on the object side of the measurement position when the tip of the contact portion of the conical probe is brought into contact with the outer peripheral end portion of the first image side lens surface.

[0014] Here, in the present invention, the image side flange surface is provided with an inclined surface portion that inclines from the outer peripheral end of the first image side lens surface toward the outer peripheral side in a direction away from the first object side lens surface, so that the position of the outer peripheral end of the first image side lens surface can be set to a position close to the first object side lens surface. This makes it possible to reduce the tangent angle at the outer peripheral end of the first image side lens surface. Therefore, when an attempt is made to replace the first lens with a resin lens having a lower refractive index than glass for a lens unit designed on the premise of using a glass lens as the first lens, even if the recess of the first image side lens surface of the first lens toward the first object side lens surface becomes deeper due to the difference in refractive index, the tangent angle at the outer peripheral end of the first image side lens surface can be reduced. In addition, since the image-side flange surface is provided with an inclined surface portion that inclines from the outer circumferential end of the first image-side lens surface toward the outer circumferential side in a direction away from the first object-side lens surface, the position of the outer circumferential end of the first image-side lens surface can be set to a desired position in the optical axis direction while making the thickness (edge ​​thickness) of the portion of the first lens that is supported by the support portion of the lens barrel the same as that of the glass lens before the replacement. Therefore, for a lens unit designed on the premise of using a glass lens as the first lens, it is easy to replace the first lens with a resin lens having a lower refractive index than glass.

[0015] In the present invention, the tangent angle of the outer circumferential edge of the first image-side lens surface may be equal to or less than 72°. This makes it easy to measure the first image-side lens surface of the first lens by a shape measuring machine that uses a probe to measure the shape of the lens surface.

[0016] In the present invention, it is preferable that the vertical surface portion and the inclined surface portion are adjacent to each other in the radial direction, and that the inclined surface portion smoothly continues to the vertical surface portion.

[0017] In the present invention, the lens barrel has an annular seal member, and the lens barrel includes the support part, the annular part, and the second lens holding part in this order from the outer periphery side to the inner periphery side, the annular part has an annular opposing surface that faces the image side flange surface with a gap in the optical axis direction along the optical axis, the second lens is held by the second lens holding part and located radially inside the opposing surface, and the seal member can surround the second lens from the outer periphery side in a state compressed in the optical axis direction between the opposing surface and the flange surface. In this way, the seal member can seal the space communicating between the first image side lens surface and the second object side lens surface. Therefore, it is possible to prevent or suppress the intrusion of water vapor or the like between the first image side lens surface and the second object side lens surface.

[0018] In the present invention, the sealing member may surround the second lens from the outer periphery side in a state compressed in the optical axis direction between the opposing surface and the vertical surface portion, thereby making it possible to ensure sealing by the sealing member.

[0019] In the present invention, the seal member is an O-ring, and the image side flange surface is an extrusion pin that is in contact with the image side flange surface when the first lens is molded to release the first lens from a mold. The O-ring may have a pin mark, and the pin mark may be located on the outer circumferential side of a contact portion where the O-ring contacts the image-side flange surface. In this way, the O-ring and the pin mark do not overlap, so that sealing by the O-ring can be ensured.

[0020] In the present invention, the second lens includes a second object-side lens surface facing the object side and an object-side flange surface surrounding the first object-side lens from the outer periphery, the second object-side lens surface is located inside the first image-side lens surface when viewed from the optical axis direction along the optical axis, the object-side flange surface includes an object-side inclined surface portion inclined from the outer periphery end of the second object-side lens surface toward the image side, and a first annular corner portion where the first image-side lens surface and the inclined surface portion intersect is located on the object side of a second annular corner portion where the second object-side lens surface and the object-side inclined surface portion intersect. In this way, it is possible to prevent or suppress stray light that has passed through the first lens from entering the second lens through the object-side inclined surface portion of the object-side flange surface of the second lens and generating a ghost. Effect of the Invention

[0021] In the lens of the present invention, a flange surface surrounding the second lens surface is provided with an inclined surface portion that inclines from the outer circumferential edge of the second lens surface toward the outer circumferential side in a direction away from the first lens surface. This allows the position of the outer circumferential edge of the second lens surface to be set close to the first lens surface, thereby making it possible to reduce the tangent angle of the outer circumferential edge of the second lens surface.

[0022] In the lens unit of the present invention, the image side flange surface of the first lens is provided with an inclined surface portion that inclines from the outer peripheral end of the first image side lens surface toward the outer peripheral side in a direction away from the first object side lens surface. This allows the position of the outer peripheral end of the first image side lens surface to be set to a position close to the first object side lens surface, so that the tangent angle of the outer peripheral end of the first image side lens surface can be reduced. In addition, the image side flange surface of the first lens is provided with an inclined surface portion that inclines from the outer peripheral end of the first image side lens surface toward the outer peripheral side in a direction away from the first object side lens surface, so that the position of the outer peripheral end of the first image side lens surface can be set to a desired position in the optical axis direction while making the thickness (edge ​​thickness) of the part of the first lens that is supported by the support part of the lens barrel the same as that of a glass lens. Therefore, for a lens unit designed on the premise of using a glass lens as the first lens, it is easy to replace the first lens with a resin lens having a lower refractive index than glass. [Brief description of the drawings]

[0023] [Figure 1] 1 is a perspective view of a lens unit to which the present invention is applied, as viewed from the object side. [Diagram 2] 2 is a cross-sectional view taken along line AA in FIG. 1. [Diagram 3] FIG. 2 is an exploded perspective view of the lens unit of FIG. [Figure 4] FIG. 2 is a perspective view of a first lens as viewed from the image side. [Diagram 5] 4 is a partially enlarged cross-sectional view of the vicinity of an inclined surface portion of the image-side flange surface of the first lens. FIG. [Figure 6] FIG. 4 is an explanatory diagram of the manufacturing direction of the first lens. [Figure 7] 10 is an explanatory diagram of a case where the first lens does not have an inclined surface portion on the image side flange surface. FIG. [Figure 8] 13 is an explanatory diagram of a lens unit according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Lens units according to embodiments of the present invention will now be described with reference to the accompanying drawings.

[0025] (Lens unit) Fig. 1 is a perspective view of a lens unit to which the present invention is applied, as viewed from the object side. Fig. 2 is a cross-sectional view taken along line AA in Fig. 1. Fig. 3 is an exploded perspective view of the lens unit in Fig. 1. A lens unit 10 of this example is used in an imaging device mounted on an automobile or a surveillance camera. In the following description, the direction along the optical axis L of the lens unit 10 is referred to as the optical axis direction X. One side of the optical axis direction X is referred to as the object side X1, and the other side is referred to as the image side X2.

[0026] As shown in FIG. 2, the lens unit 10 of this example includes a first lens 1, a second lens 2, a third lens 3, and a fourth lens 4 in this order from the object side X1 to the image side X2. The first lens 1 and the second lens 2 each have negative power. The third lens 3 and the fourth lens 4 each have positive power. The fourth lens 4 is a cemented lens, and includes an object side lens 5 having negative power and an image side lens 6 having positive power. The lens unit 10 also includes a lens barrel 7 that holds these lenses 1 to 4. The lens unit 10 also includes an aperture 8 disposed between the third lens 3 and the fourth lens 4, and an infrared cut filter 9 disposed on the image side X2 of the fourth lens 4.

[0027] The first lens 1, the second lens 2, the third lens 3, and the fourth lens 4 constitute a wide-angle optical system having an angle of view of 180° or more. Here, the first lens 1, the second lens 2, the third lens 3, the object-side lens 5, and the image-side lens 6 are all made of resin. As shown in FIG. 2, the first lens 1 has a larger outer diameter than the second lens 2, the third lens 3, and the fourth lens 4. The second lens 2, the third lens 3, and the fourth lens 4 have smaller outer diameters in this order.

[0028] The lens barrel 7 includes a first lens barrel portion 15, a second lens barrel portion 16 located on the inner periphery side of the first lens barrel portion 15, and an annular portion 17 connecting the first lens barrel portion 15 and the second lens barrel portion 16. The first lens 1 is held by a first lens holder 21 provided at an end portion of the first lens barrel portion 15 on the object side X1. The second lens 2 to the fourth lens 4 are housed in a stacked state on the inner periphery side of the second lens barrel portion 16. The annular portion 17 connects a portion of the first lens barrel portion 15 adjacent to the image side X2 of the first lens holder 21 to an end portion of the second lens barrel portion 16 on the object side X1.

[0029] 2 and 3, the first lens holding portion 21 includes an annular wall portion 22 which is an end portion of the first barrel portion 15 on the object side X1, a support portion 23 which supports the first lens 1 from the image side X2, and a first contact portion 24 which contacts the outer periphery of the first lens 1 from the object side X1. The first contact portion 24 is provided by plastically deforming the tip portion of the first barrel portion 15 toward the inner periphery by crimping. As shown in FIG. 2, when the first lens 1 is inserted into the annular wall portion 22, its outer periphery portion is sandwiched from both sides in the optical axis direction X by the support portion 23 and the first contact portion 24, and is fixed to the first barrel portion 15.

[0030] The second barrel portion 16 is provided with an annular protrusion 31 that protrudes inward from an end portion of the image side X2. The protrusion 31 has an annular end face 31a facing the object side X1. The protrusion 31 also has an annular plate portion 32 that protrudes inward from the end portion of the image side X2. An inner diameter dimension of an inner peripheral surface portion 33 on the object side X1 than the annular end face 31a on the inner peripheral surface of the second barrel portion 16 becomes larger in a stepped manner toward the object side X1.

[0031] The object-side lens 5 of the fourth lens 4 is placed on the annular end surface 31a of the protruding portion 31. That is, the fourth lens 4 has an outer peripheral edge portion of the object-side lens 5 that protrudes more outer circumferentially than the image-side lens 6 placed on the annular end surface 31a, and the image-side X2 portion of the image-side lens 6 is disposed on the object side X1 of the annular plate portion 32 on the inner peripheral side of the protruding portion 31. The fourth lens 4 is positioned in the optical axis direction X by the object-side lens 5 being placed on the annular end surface 31a, and is positioned in the radial direction by the outer peripheral surface of the object-side lens 5 coming into contact with the inner peripheral surface portion 33 of the second barrel portion 16.

[0032] The third lens 3 is stacked on the object side X1 of the fourth lens 4 via the diaphragm 8. The third lens 3 is positioned in the optical axis direction X by being stacked on the object side X1 of the fourth lens 4. In addition, the third lens 3 is positioned in the radial direction by its outer circumferential surface coming into contact with an inner circumferential surface portion 33 of the second barrel portion 16.

[0033] The second lens 2 is stacked on the object side X1 of the third lens 3. The second lens 2 is positioned in the optical axis direction X by being stacked on the object side X1 of the third lens 3. The second lens 2 is positioned in the radial direction by its outer circumferential surface contacting the inner circumferential surface portion 33 of the second barrel portion 16. Furthermore, the second lens 2 is contacted by a second contact portion 34 provided at the tip of the second barrel portion 16 from the object side X1. The second contact portion 34 is provided by plastically deforming the tip portion of the second barrel portion 16 to the inner circumferential side by caulking. The second contact portion 34 prevents the second lens 2 from moving to the object side X1. The end portion of the object side X1 of the second barrel portion 16 is a second lens holding portion 35 that holds the second lens 2.

[0034] As shown in FIG. 2, the lens barrel 7 includes, from the outer periphery toward the inner periphery, the support portion 23 of the first lens barrel portion 15, the annular portion 17, and the second lens holding portion 35 of the second lens barrel portion 16, in this order. The annular portion 17 includes an annular facing surface 17a that faces the first lens 1 with a gap in the optical axis direction X. The second lens 2 is held by the second lens holding portion 35 and is located radially inside the facing surface 17a. An annular seal member is disposed on the facing surface 17a. The seal member is an O-ring 36. The O-ring 36 surrounds the second lens 2 from the outer periphery while being compressed in the optical axis direction X between the facing surface 17a and the first lens 1.

[0035] (1st lens, 2nd lens, and O-ring) Next, the first lens 1 (lens), the second lens 2, and the O-ring 36 will be described in detail. Fig. 4 is a perspective view of the first lens 1 as viewed from the image side X2. Fig. 5 is a partially enlarged cross-sectional view of the vicinity of the inclined surface portion of the flange surface 43 of the first lens 1. Fig. 6 is an explanatory diagram of a manufacturing method of the first lens 1.

[0036] As shown in FIG. 1, FIG. 2, FIG. 4, and FIG. 5, the first lens 1 has a first object side lens surface 41 (first lens surface) facing the object side X1, a first image side lens surface 42 (second lens surface) facing the image side X2, and an image side flange surface 43 (flange surface) surrounding the first image side lens surface 42 from the outer periphery side. The second lens surface 42 and the image side flange surface 43 face the opposite side to the first lens surface 41. The first lens 1 is a meniscus lens, and the first object side lens surface 41 has a convex shape protruding toward the object side X1. The first image side lens surface 42 has a concave shape recessed toward the object side X1. As shown in FIG. 2 and FIG. 4, the image side flange surface 43 has an inclined surface portion 45 inclined toward the image side X2 from the outer periphery end of the first image side lens surface 42 toward the outer periphery side, and a vertical surface portion 46 perpendicular to the optical axis L on the outer periphery side of the inclined surface portion 45. When viewed from the optical axis direction X, the vertical surface portion 46 overlaps with the outer circumferential portion of the first object-side lens surface 41. Moreover, the vertical surface portion 46 is located closer to the image side X2 than the first image-side lens surface 42 and the inclined surface portion 45. The outer circumferential surface 44 of the first lens 1 extends in the optical axis direction X and connects the outer circumferential end of the first object-side lens surface 41 and the outer circumferential end of the image-side flange surface 43. The outer circumferential surface 44 of the first lens 1 has a predetermined width in the optical axis direction X. In this example, the image-side flange surface 43 is painted with ink.

[0037] As shown in FIG. 4 and FIG. 5, the vertical surface portion 46 and the inclined surface portion 45 of the image side flange surface 43 are adjacent to each other in the radial direction. The inclined surface portion 45 smoothly continues to the vertical surface portion 46. More specifically, the inclined surface portion 45 includes a first tapered surface portion 45a that is inclined from the first image side lens surface 42 toward the image side X2 toward the outer periphery, a first curved surface portion 45b that is curved toward the image side X2 toward the outer periphery from the outer periphery end of the first tapered surface portion 45a, a second tapered surface portion 45c that is inclined toward the outer periphery from the outer periphery end of the first curved surface portion 45b toward the image side X2, and a second curved surface portion 45d that is curved toward the outer periphery from the outer periphery end of the second tapered surface portion 45c toward the image side X2. The outer periphery end of the second curved surface portion 45d smoothly continues to the vertical surface portion 46.

[0038] 5, the tangent angle θ1 of the outer peripheral end of the first image side lens surface 42 (the end of the first image side lens surface 42 on the image side X2) is 72° or less. The outer peripheral end of the first image side lens surface 42 is the angle at which the first image side lens surface 42 and the inclined surface portion 45 of the image side flange surface 43 intersect in the first lens 1. The tangent angle θ1 at the outer circumferential end of the first image-side lens surface 42 is the angle at which a tangent L1 at the outer circumferential end of the first image-side lens surface 42 intersects with a virtual line L2 perpendicular to the optical axis L, and is the angle from the virtual line L2 to the tangent L1 toward the object side X1, on the optical axis side of the outer circumferential end of the first image-side lens surface 42.

[0039] 4, the first lens 1 has a gate mark 47 on part of the circumferential direction of the outer circumferential surface 44. Furthermore, the first lens 1 has ejector pin marks 48 on the vertical surface portion 46 at multiple points in the circumferential direction.

[0040] That is, the first lens 1 is a resin molded product molded by injecting resin into a cavity 52 of a mold 51 as shown in FIG. 6. The mold 51 for molding the first lens 1 includes a movable mold 53 and a fixed mold 54 as shown in FIG. 6(a). The movable mold 53 advances and retreats relative to the fixed mold 54. The movable mold 53 includes an object side transfer surface 53a for transferring the first object side lens surface 41 on a surface facing the fixed mold 54 in the moving direction Y of the movable mold 53. The fixed mold 54 includes an image side transfer surface 54a for transferring the first image side lens surface 42 and the image side flange surface 43 on a surface facing the movable mold 53. The fixed mold 54 also includes a gate 55 communicating with the cavity 52 from a direction perpendicular to the moving direction of the movable mold 53. Furthermore, the fixed mold 54 includes an ejection pin 56 for releasing the molded product from the fixed mold 54. The ejection pin 56 is capable of protruding from the outer periphery of the image side transfer surface 54 a of the fixed mold 54 toward the movable mold 53 .

[0041] As shown in FIG. 6(a), the movable die 53 and the fixed die 54 are overlapped in the moving direction Y of the movable die 53, and a cavity 52 is formed between them. In the molding process of the first lens 1, first, a resin is injected into the cavity 52 through the gate 55. When the resin hardens in the cavity 52, the movable die 53 is moved in a direction away from the fixed die 54, as shown in FIG. 6(b). Thereafter, as shown in FIG. 6(c), the ejection pin 56 is caused to protrude from the image side transfer surface 54a of the fixed die 54 toward the movable die 53, and the molded body (first lens 1) is released from the fixed die 54. The gate mark 47 is a portion of the molded body where the gate 55 was connected. The ejection pin mark 48 is a mark where the ejection pin 56 was in contact when the first lens 1 was molded.

[0042] Next, as shown in FIG. 2, the second lens 2 has a second object-side lens surface 61 facing the object side X1, an object-side flange surface 62 surrounding the second object-side lens surface 61 from the outer periphery, a second image-side lens surface 63 facing the image side X2, and a second image-side flange surface 64 surrounding the second image-side lens surface 63 from the outer periphery. The second lens 2 is a meniscus lens. The second object-side lens surface 61 has a convex shape protruding toward the object side X1. The second image-side lens surface 63 has a concave shape recessed toward the object side X1. The object-side flange surface 62 has an object-side inclined surface portion 65 inclined from the outer periphery end of the second object-side lens surface 61 toward the image side X2 toward the outer periphery side, and an object-side vertical surface portion 66 extending from the outer periphery end of the object-side inclined surface portion 65 in a direction perpendicular to the optical axis L. The second image-side flange surface 64 is a plane and perpendicular to the optical axis L. The second image-side flange surface 64 abuts against the third lens 3 .

[0043] Here, as can be seen from FIG. 2 and FIG. 3, when the state in which the first lens 1 and the second lens 2 are held in the lens barrel 7 is viewed from the optical axis direction X, the second object-side lens surface 61 of the second lens 2 is located on the inner circumference of the first image-side lens surface 42 of the first lens 1. As shown in FIG. 5, the first annular corner portion 49 where the first image-side lens surface 42 and the inclined surface portion 45 of the image-side flange surface 43 intersect in the first lens 1 is located on the object side X1 from the second annular corner portion 69 where the second object-side lens surface 61 and the object-side inclined surface portion 65 of the object-side flange surface 62 intersect in the second lens 2. Also, as shown in FIG. 2, the O-ring 36 placed on the annular portion 17 is in contact with the image-side flange surface 43 of the first lens 1 and is in a state of being compressed in the optical axis direction X. The ejection pin mark 48 is located on the outer periphery side from the contact portion 36a where the O-ring 36 contacts the image-side flange surface 43.

[0044] (Action and effect) The lens unit 10 of this example includes a first lens 1, a second lens 2 located next to the image side X2 of the first lens 1, and a lens barrel 7 that holds the first lens 1 and the second lens 2. The first lens 1 is made of resin and includes a first object side lens surface 41 facing the object side X1, a first image side lens surface 42 facing the image side X2, and an image side flange surface 43 that surrounds the first image side lens surface 42 from the outer periphery side. The first image side lens surface 42 has a concave shape that is recessed toward the object side X1. The image side flange surface 43 includes an inclined surface portion 45 that inclines from the outer periphery end of the first image side lens surface 42 toward the outer periphery side toward the image side X2, and a vertical surface portion 46 that is perpendicular to the optical axis L on the outer periphery side of the inclined surface portion 45. The lens barrel 7 includes a support portion 23 that supports the vertical surface portion 46 from the image side X2.

[0045] According to this example, the image-side flange surface 43 surrounding the first image-side lens surface 42 from the outer circumferential side includes an inclined surface portion 45 that inclines from the outer circumferential end of the first image-side lens surface 42 toward the image side X2 toward the outer circumferential side. Therefore, for example, compared to a case in which the entire image-side flange surface 43 is made of a vertical surface perpendicular to the optical axis L and the first image-side lens surface 42 is extended in the optical axis direction X until it reaches the image-side flange surface 43, the outer circumferential end of the first image-side lens surface 42 can be set to a position P1 closer to the first object-side lens surface 41. As a result, the tangent L1 of the outer circumferential end of the first image-side lens surface 42 inclines toward the optical axis L toward the object side X1, and the tangent angle θ1 becomes smaller.

[0046] FIG. 7 is an explanatory diagram of a case where the first lens 1 does not have an inclined surface portion 45 on the image side flange surface 43. As shown in FIG. 7, when the entire image side flange surface 43 is made of a vertical surface perpendicular to the optical axis L and the first image side lens surface 42 is extended in the optical axis direction X until it reaches the image side flange surface 43, the outer peripheral end (first corner portion 49) of the first image side lens surface 42 is at position P2 shown in FIG. 7, which is closer to the image side X2 than position P1 shown in FIG. 5. As a result, the tangent L1 of the outer peripheral end of the first image side lens surface 42 approaches a state parallel to the optical axis L, so that the tangent angle θ2 becomes large. Here, as shown in FIG. 7, when the tangent angle θ2 becomes large, the angle of the first corner portion 49 becomes narrow. Therefore, when manufacturing the lens shown in FIG. 6, it becomes difficult to separate the lens of the molded body from the mold 51 (fixed mold 54).

[0047] In contrast, as in the first lens 1 of this example, if an inclined surface portion 45 is provided on the image side flange surface 43 surrounding the first image side lens surface 42 from the outer periphery side, inclining from the outer periphery end of the first image side lens surface 42 toward the image side X2 toward the outer periphery side, the position of the outer periphery end of the first image side lens surface 42 can be moved to a position P1 on the object side. Therefore, the tangent angle θ1 can be made small. Here, if the tangent angle θ1 is made small, the angle of the first corner portion 49 becomes wider, so that it becomes easier to separate the lens of the molded body from the mold 51 (fixed mold 54) during lens manufacturing.

[0048] Moreover, the image side flange surface 43 includes an inclined surface portion 45 connected to the first image side lens surface 42. The inclined surface portion 45 is inclined from the outer peripheral end of the first image side lens surface 42 toward the outer peripheral side in a direction away from the first object side lens surface 41. In this way, as can be seen from Fig. 5 and Fig. 7, the angle at which the first image side lens surface 42 and the image side flange surface 43 intersect (the angle of the first corner portion 49) becomes large. Therefore, it becomes easier to separate the lens of the molded body from the mold 51.

[0049] Here, when the angle at which the first image side lens surface 42 and the image side flange surface 43 intersect becomes large, it becomes easier to process the inside corner portion K1 (see FIG. 6(c)) for forming the first corner portion 49 at which the first image side lens surface 42 and the image side flange surface 43 intersect in the mold 51. That is, when the angle of the first corner portion 49 at which the first image side lens surface 42 and the image side flange surface 43 intersect approaches a right angle, the difficulty of processing the inside corner portion K1 that forms the corner portion in the mold 51 increases. In contrast, in this example, the first corner portion 49 at which the first image side lens surface 42 and the image side flange surface 43 intersect becomes large, so that the processing of the inside corner portion K1 is easier and the manufacturing of the mold 51 is easier.

[0050] Furthermore, according to this example, the tangent angle θ1 of the outer circumferential end of the first image-side lens surface 42 can be made small, so that it becomes easy to measure the shape of the first image-side lens surface 42 by bringing a probe into contact with the first image-side lens surface 42 from the image side X2 in the optical axis direction X. That is, since the tangent angle θ1 of the outer circumferential end of the first image-side lens surface 42 can be made small, it becomes possible to avoid the base end side of the contact portion 70a of the probe 70 interfering with the end of the first image-side lens surface 42 located on the object side X1 from the measurement position when the tip of the contact portion 70a of the conical probe 70 is brought into contact with the outer circumferential end portion of the first image-side lens surface 42, as shown in FIG.

[0051] In addition, in this example, the image side flange surface 43 is provided with an inclined surface portion 45 that inclines from the outer peripheral end of the first image side lens surface 42 toward the outer peripheral side in a direction away from the first object side lens surface 41, so that the position P1 of the outer peripheral end of the first image side lens surface 42 can be set to a position close to the first object side lens surface 41. This makes it possible to reduce the tangent angle θ1 at the outer peripheral end of the first image side lens surface 42. Therefore, when an attempt is made to replace the first lens 1 with a resin lens having a lower refractive index than glass for the lens unit 10 designed on the premise of using a glass lens for the first lens 1, even if the recess of the first image side lens surface 42 of the first lens 1 becomes deeper due to the difference in refractive index and the first image side lens surface 42 approaches a hemispherical shape, the tangent angle θ1 at the outer peripheral end of the first image side lens surface 42 can be reduced. Furthermore, image-side flange surface 43 is provided with inclined surface portion 45 that inclines from the outer circumferential end of first image-side lens surface 42 toward the outer circumferential side in a direction away from first object-side lens surface 41, so that position P1 of the outer circumferential end of first image-side lens surface 42 can be set to a desired position in optical axis direction X while keeping the thickness (edge ​​thickness) of the portion of first lens 1 supported by support portion 23 of barrel 7 the same as that of the glass lens before the replacement. Therefore, for lens unit 10 designed on the premise of using a glass lens for first lens 1, it is easy to replace first lens 1 with a resin lens having a lower refractive index than glass.

[0052] In this example, the tangent angle θ1 of the outer circumferential end of the first image-side lens surface 42 is equal to or smaller than 72°. In this way, it becomes easy to measure the first image-side lens surface 42 of the first lens 1 by a shape measuring machine that uses a probe 70 to measure the shape of the lens surface.

[0053] Here, position P1 of the outer circumferential edge of the first image-side lens surface 42 can be moved toward the object side X1 within a range where effective light rays passing through the first lens 1 do not pass through. Therefore, depending on the optical design of the first lens 1, the tangent angle θ1 of the outer circumferential edge of the first image-side lens surface 42 can be made smaller than 70°. In addition, the surface shape and inclination angle of the inclined surface portion 45 can be set arbitrarily.

[0054] In this example, the vertical surface portion 46 and the inclined surface portion 45 are adjacent to each other in the radial direction, and the inclined surface portion 45 smoothly continues to the vertical surface portion 46. Therefore, when the O-ring 36 comes into contact with the image side flange surface 43, the O-ring is not scratched. Also, it is easy to apply ink to the image side flange surface 43.

[0055] Furthermore, the lens unit 10 of this example has an annular O-ring 36 (sealing member). The lens barrel 7 includes the support portion 23, the annular portion 17, and the second lens holding portion 35 in this order from the outer periphery side to the inner periphery side. The annular portion 17 includes an annular opposing surface 17a that faces the image-side flange surface 43 with a gap in the optical axis direction X along the optical axis L. The second lens 2 is held by the second lens holding portion 35 and is located radially inside the opposing surface 17a. The O-ring 36 surrounds the second lens 2 from the outer periphery side in a state compressed in the optical axis direction X between the opposing surface 17a and the flange surface. This allows the O-ring 36 to seal the space communicating between the first image-side lens surface 42 and the second object-side lens surface 61. This allows water vapor and the like to be prevented or suppressed from entering between the first image-side lens surface 42 and the second object-side lens surface 61.

[0056] Furthermore, in this example, the image-side flange surface 43 has an ejector pin mark 48 where an ejector pin 56 that releases the first lens 1 from the mold 51 during molding of the first lens 1 made contact. The ejector pin mark 48 is located on the outer periphery side of a contact portion 36a where the O-ring 36 makes contact with the image-side flange surface 43. This prevents the O-ring 36 and the ejector pin mark 48 from overlapping, ensuring reliable sealing by the O-ring 36.

[0057] Further, in this example, the second lens 2 includes a second object-side lens surface 61 facing the object side X1, and an object-side flange surface 62 surrounding the second object-side lens surface 61 from the outer periphery side. When viewed from the optical axis direction X, the second object-side lens surface 61 is located inside the first image-side lens surface 42. The object-side flange surface 62 includes an object-side inclined surface portion 65 that inclines from the outer periphery side end of the second object-side lens surface 61 toward the image side X2. The first annular corner portion 49 where the first image-side lens surface 42 and the inclined surface portion 45 intersect is located closer to the object side X1 than the second annular corner portion 69 where the second object-side lens surface 61 and the object-side inclined surface portion 65 intersect. Therefore, it is possible to prevent or suppress stray light that has passed through the first lens 1 from entering the second lens 2 through the object-side inclined surface portion 65 of the object-side flange surface 62 of the second lens 2 and generating a ghost.

[0058] (Modification) FIG. 8 is an explanatory diagram of a lens unit of a modified example. In the above example, the O-ring 36 abuts against the boundary between the inclined surface portion 45 and the vertical surface portion 46 on the flange surface of the first lens. In contrast, in the lens unit 10A of the modified example shown in FIG. 8, the vertical surface portion 46 is extended toward the inner periphery side, so that the O-ring 36 (sealing member) abuts against the vertical surface portion 46. That is, the O-ring 36 surrounds the second lens 2 from the outer periphery side in a state in which it is compressed in the optical axis direction X between the opposing surface 17a and the vertical surface portion 46. Here, the other configurations of the lens unit 10A are the same as those of the lens unit 10. According to this example, the sealing by the O-ring 36 (sealing member) can be ensured.

[0059] Here, the present technology can have the following configurations. (1) A lens unit having a first lens, a second lens located adjacent to the image side of the first lens, and a barrel that holds the first lens and the second lens, wherein the first lens is made of resin and has a first object-side lens surface facing the object side, a first image-side lens surface facing the image side, and an image-side flange surface that surrounds the first image-side lens surface from an outer circumferential side, the first image-side lens surface having a concave shape that is recessed toward the object side, the image-side flange surface having an inclined surface portion that slopes from an outer circumferential end of the first image-side lens surface toward the image side from the outer circumferential side, and a vertical surface portion that is perpendicular to the optical axis on the outer circumferential side of the inclined surface portion, and the barrel has a support portion that supports the vertical surface portion from the image side.

[0060] (2) The lens unit described in (1), wherein a tangent angle of an outer peripheral edge of the first image-side lens surface is 72° or less.

[0061] (3) The lens unit described in (1) or (2), wherein the vertical surface portion and the inclined surface portion are adjacent to each other in the radial direction, and the inclined surface portion smoothly continues to the vertical surface portion.

[0062] (4) A lens unit described in any one of (1) to (3), characterized in that the lens barrel has the support portion, the annular portion, and the second lens holding portion in this order from the outer circumferential side to the inner circumferential side, the annular portion has an annular opposing surface facing the image side flange surface with a gap in the optical axis direction along the optical axis, the second lens is held by the second lens holding portion and positioned radially inside the opposing surface, and the sealing member surrounds the second lens from the outer circumferential side while being compressed in the optical axis direction between the opposing surface and the flange surface.

[0063] (5) The lens unit described in (4), wherein the sealing member surrounds the second lens from the outer periphery while being compressed in the optical axis direction between the opposing surface and the vertical surface portion.

[0064] (6) The lens unit described in (4) or (5), characterized in that the sealing member is an O-ring, the image-side flange surface has an ejection pin mark where an ejection pin that releases the first lens from a mold during molding of the first lens was in contact, and the ejection pin mark is located on the outer periphery side of the contact portion where the O-ring contacts the image-side flange surface.

[0065] (7) The lens unit described in any one of claims (1) to (6), characterized in that the second lens has a second object-side lens surface facing the object side and an object-side flange surface surrounding the first object-side lens from the outer circumferential side, the second object-side lens surface being located inside the first image-side lens surface when viewed from the optical axis direction, the object-side flange surface having an object-side inclined surface portion that inclines outer circumferentially from an end of the outer circumferential side of the second object-side lens surface toward the image side, and a first annular corner portion where the first image-side lens surface and the inclined surface portion intersect is located on the object side of a second annular corner portion where the second object-side lens surface and the object-side inclined surface portion intersect. [Explanation of symbols]

[0066] 1...first lens, 2...second lens, 3...third lens, 4...fourth lens, 5...object-side lens, 6...image-side lens, 7...lens barrel, 8...diaphragm, 9...infrared cut filter, 10...lens unit, 15...first lens barrel portion, 16...second lens barrel portion, 17...annular portion, 17a...opposing surface, 21...first lens holding portion, 22...annular wall portion, 23...support portion, 24...first contact portion, 31... Projection portion, 31a... annular end surface, 32... annular plate portion, 33... inner peripheral surface portion, 34... second contact portion, 35... second lens holding portion, 36... O-ring (sealing member), 36a... contact portion, 41... first object side lens surface (first lens surface), 42... first image side lens surface (second lens surface), 43... image side flange surface (flange surface), 44... outer peripheral surface, 45... inclined surface portion, 45a... first tape par surface portion, 45b...first curved surface portion, 45c...second tapered surface portion, 45d...second curved surface portion, 46...vertical surface portion, 47...gate mark, 48...ejector pin mark, 49...first corner portion, 51...mold, 52...cavity, 53...movable mold, 53a...object side transfer surface, 54...fixed mold, 54a...image side transfer surface, 55...gate, 56...ejector pin, 61...second object side lens surface, 62...object side flange surface, 63...second image side lens surface, 64...second image side flange surface, 65...object side inclined surface portion, 66...object side vertical surface portion, 69...second corner portion, 70...probe, 70a...contact portion, L...optical axis, L1...tangent line, L2...virtual line, P1...position of outer periphery end of first image side lens surface, X...optical axis direction, X1...object side, X2...image side, θ1...tangent angle, θ2...tangent angle

Claims

1. a first lens surface, a second lens surface facing a side opposite to the first lens, and a flange surface surrounding the second lens surface from an outer periphery side; the second lens surface has a concave shape recessed toward the first lens surface, the flange surface includes an inclined surface portion inclined from an outer circumferential end of the second lens surface toward the outer circumferential side in a direction away from the first lens surface, and a vertical surface portion perpendicular to the optical axis on the outer circumferential side of the inclined surface portion, A lens made of resin.

2. 2. The lens according to claim 1, wherein a tangent angle of the outer peripheral edge of the second lens surface is 72[deg.] or less.

3. The vertical surface portion and the inclined surface portion are adjacent to each other in a radial direction, The lens according to claim 1 , wherein the inclined surface portion smoothly connects to the vertical surface portion.

4. A lens unit having a first lens, a second lens located adjacent to the image side of the first lens, and a lens barrel that holds the first lens and the second lens, the first lens is made of resin and has a first object-side lens surface facing an object side, a first image-side lens surface facing the image side, and an image-side flange surface surrounding the first image-side lens surface from an outer periphery side, the first image-side lens surface has a concave shape recessed toward the object side, the image-side flange surface includes an inclined surface portion inclined toward the image side from an outer circumferential end of the first image-side lens surface toward the outer circumferential side, and a vertical surface portion perpendicular to the optical axis on the outer circumferential side of the inclined surface portion, The lens unit according to claim 1, wherein the lens barrel includes a support portion that supports the vertical surface portion from the image side.

5. 5. The lens unit according to claim 4, wherein a tangent angle of an outer circumferential edge of the first image-side lens surface is 72[deg.] or less.

6. The vertical surface portion and the inclined surface portion are adjacent to each other in a radial direction, 5. The lens unit according to claim 4, wherein the inclined surface portion smoothly connects to the vertical surface portion.

7. A ring-shaped seal member is provided. the lens barrel includes, from an outer periphery to an inner periphery, the support portion, an annular portion, and a second lens holding portion in this order, the annular portion includes an annular opposing surface that faces the image-side flange surface with a gap therebetween in an optical axis direction along the optical axis, the second lens is held by the second lens holder and positioned radially inward of the opposing surface, The lens unit according to claim 4 , wherein the seal member surrounds the second lens from an outer periphery side in a state where the seal member is compressed in the optical axis direction between the opposing surface and the flange surface.

8. The lens unit according to claim 7 , wherein the seal member surrounds the second lens from an outer periphery side in a state where the seal member is compressed in the optical axis direction between the opposing surface and the vertical surface portion.

9. The sealing member is an O-ring, the image-side flange surface has an ejection pin mark with which an ejection pin that releases the first lens from a mold during molding of the first lens has been in contact, 9. The lens unit according to claim 7, wherein the ejection pin mark is located on the outer circumferential side of a contact portion where the O-ring contacts the image side flange surface.

10. the second lens includes a second object-side lens surface facing the object side, and an object-side flange surface surrounding the first object-side lens from an outer periphery side, the second object-side lens surface is located inside the first image-side lens surface when viewed from an optical axis direction along the optical axis, the object-side flange surface includes an object-side inclined surface portion inclined toward the outer periphery from an end of the second object-side lens surface on the outer periphery side toward the image side, 5. The lens unit according to claim 4, wherein a first annular corner portion where the first image-side lens surface and the inclined surface portion intersect is located closer to the object side than a second annular corner portion where the second object-side lens surface and the object-side inclined surface portion intersect.

Images