Lens and lens unit

Abstract

The invention provides a resin lens and a lens unit capable of reducing a tangent angle at an outer peripheral end of a concave lens surface. A lens unit (10) has a first lens (1), a second lens (2) positioned next to an image side (X2) of the first lens, and a lens barrel (7) holding the first lens and the second lens. The first lens is made of resin and has 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) surrounding the first image-side lens surface from the outer peripheral side. The first image-side lens surface has a concave shape that is recessed toward the object side (X1). The image-side flange surface is provided with: an inclined surface section (45) inclined toward the image side from the outer peripheral end of the first image-side lens surface toward the outer peripheral side; and a perpendicular surface section (46) perpendicular to the optical axis (L) on the outer peripheral side of the inclined surface section. The lens barrel is provided with a support section (23) that supports the vertical surface section from the image side.

Description

Technical Field

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

[0002] Patent document 1 describes a lens unit having a first lens, a plurality of lenses arranged on the image side of the first lens, and a lens barrel holding these lenses. In the 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 surrounding the second image side lens surface from the peripheral side. The first lens is a concave-convex lens, and the first lens surface has a convex shape protruding toward the object side. The second lens surface has a concave shape recessed toward the object side. The flange surface is perpendicular to the optical axis of the first lens. A shading plate is installed on 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 shading plate. Prior art literature Patent Literature

[0003] Patent Document 1: Japanese Patent Application Publication No. 2009-216774 Summary of the invention

[0004] Problems to be solved by the invention In the lens unit of the wide-angle optical system described in Patent Document 1, the first lens is mostly made of glass with a high refractive index. However, compared with a resin lens, a glass lens has poor formability and is prone to increase manufacturing costs. Therefore, for a lens unit designed on the premise that the first lens is a glass lens, attempts have been made to replace the first lens with a resin lens with a lower refractive index than glass.

[0005] In the case of obtaining the same optical characteristics as a glass lens through a resin lens, due to the difference in refractive index, the concave of the second lens surface of the lens sometimes becomes deeper, and the second lens surface approaches a hemispherical shape. In this case, the tangent angle at the outer peripheral end of the second lens surface approaches a right angle. That is, when the second lens surface approaches a hemispherical shape, the inclination of the tangent at the outer peripheral end of the second lens surface approaches a state parallel to the optical axis.

[0006] Here, when the inclination of the tangent at the outer end of the second lens surface is close to being parallel to the optical axis, the angle at which the flange surface perpendicular to the optical axis and the second lens surface intersect is close to a right angle. When the angle at which the second lens surface and the flange surface intersect is close to a right angle, it is difficult to demold the lens of the molded body from the mold when manufacturing the lens, compared to the case where the angle at which the second lens surface and the flange surface intersect is less than a right angle. In addition, when the inclination of the tangent at the outer end of the second lens surface is close to being parallel to the optical axis, it is sometimes difficult to make the probe contact the second lens surface from the image side of the optical axis direction to measure the shape of the second lens surface. That is, when the inclination of the tangent at the outer end of the second lens surface is close to being parallel to the optical axis, when the front end of the contact portion of the conical probe is to be brought into contact with the outer end portion of the second lens surface, sometimes the base end side of the contact portion of the probe interferes with the end of the second lens surface on the object side than 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 a tangent angle at an outer peripheral end of a concave lens surface. Another object of the present invention is to provide a lens unit having such a lens.

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

[0009] According to the present invention, the flange surface surrounding the second lens surface from the outer peripheral side is provided with an inclined surface portion that is inclined from the outer peripheral end of the second lens surface toward the outer peripheral side and in a direction away from the first lens surface. Therefore, for example, compared with the case where the entire flange surface is composed of a vertical surface perpendicular to the optical axis and the second lens surface is extended along the optical axis direction to reach the flange surface, the position of the outer peripheral end of the second lens surface can be set at a position close to the first lens surface. As a result, the tangent of the outer peripheral end of the second lens surface is inclined toward the optical axis side toward the first lens side, and therefore, the tangent angle of the outer peripheral end can be reduced. Therefore, when manufacturing the lens, it is easy to demold the lens of the molded body from the mold. In addition, the flange surface is provided with an inclined surface portion connected to the second lens surface. The inclined surface portion is inclined from the outer peripheral end of the second lens surface toward the outer peripheral side and in a direction away from the first lens surface. As a result, the angle at which the second lens surface intersects with the flange surface becomes larger, and therefore, it is easier to demold the lens of the molded body from the mold. In addition, according to the present invention, since the tangent angle of the outer peripheral end of the second lens surface can be reduced, it is easy to make the probe contact the second lens surface from the image side in the optical axis direction to measure the shape of the second lens surface. That is, since the tangent angle of the outer peripheral end of the second lens surface can be reduced, when the tip of the contact portion of the conical probe is to be brought into contact with the outer peripheral end portion of the second lens surface, it is possible to avoid interference between the base end side of the contact portion of the probe and the end of the second lens surface on the object side relative to the measurement position.

[0010] In the present invention, the tangent angle of the outer peripheral end of the second lens surface may be 72° or less. In this way, the second lens surface can be easily measured by a shape measuring machine that measures the shape of the lens surface using a probe.

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

[0012] Next, the lens unit of the present invention comprises: a first lens; a second lens located next to the image side of the first lens; and a lens barrel that holds the first lens and the second lens, wherein the first lens is made of resin and comprises: 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 the outer peripheral 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 inclined toward the image side from the outer peripheral end of the first image side lens surface toward the outer peripheral side; and a vertical surface portion perpendicular to the optical axis on the outer peripheral side of the inclined surface portion, and the lens barrel has a supporting 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 peripheral side is provided with an inclined surface portion inclined toward the image side from the outer peripheral end of the first image side lens surface toward the outer peripheral side. Therefore, for example, compared with the case where the entire image side flange surface is composed of a vertical surface perpendicular to the optical axis and the first image side lens surface is extended along the optical axis direction to reach the image side flange surface, the position of the outer peripheral end of the first image side lens surface can be set at a position close to the first object side lens surface. As a result, the tangent of the outer peripheral end of the first image side lens surface is inclined toward the object side and toward the optical axis side, so that the tangent angle of the outer peripheral end can be reduced. As a result, when manufacturing the lens, it is easy to demold the lens of the molded body from the mold. In addition, the image side flange surface is provided with 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 and in the direction of separation from the first object side lens surface. As a result, the angle at which the first image side lens surface intersects with the image side flange surface becomes larger, so that it is easier to demold the lens of the molded body from the mold. Furthermore, according to the present invention, since the tangent angle of the outer peripheral end of the first image side lens surface can be reduced, it is easy to make the probe contact the first image side lens surface from the image side in the optical axis direction to measure the shape of the first image side lens surface. That is, since the tangent angle of the outer peripheral end of the first image side lens surface can be reduced, when the tip of the contact portion of the conical probe is to be brought into contact with the outer peripheral end portion of the first image side lens surface, it is possible to avoid interference between the base end side of the contact portion of the probe and the end portion of the first image side lens surface that is closer to the object side than the measurement position.

[0014] Here, in the present invention, by providing an inclined surface portion on the image side flange surface that is inclined from the outer peripheral end of the first image side lens surface toward the outer peripheral side and in a direction away from the first object side lens surface, the position of the outer peripheral end of the first image side lens surface can be set at a position close to the first object side lens surface. Thus, the tangent angle of the outer peripheral end of the first image side lens surface can be reduced. Therefore, for a lens unit designed on the premise that the first lens uses a glass lens, in the case of attempting to replace the first lens with a resin lens having a lower refractive index than glass, even if the depression of the first image side lens surface of the first lens toward the first object side lens surface side becomes deeper due to the difference in refractive index, the tangent angle of 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 is inclined from the outer peripheral end of the first image side lens surface toward the outer peripheral side and in a direction away from the first object side lens surface, the thickness (edge ​​thickness) of the portion of the first lens supported by the support portion of the lens barrel can be made the same as that of the glass lens before replacement, and the position of the outer peripheral end of the first image side lens surface can be set at a desired position in the optical axis direction. Therefore, in a lens unit designed on the premise that a glass lens is used 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 peripheral end of the first image side lens surface may be less than or equal to 72°. In this way, the first image side lens surface of the first lens can be easily measured by a shape measuring machine that measures the shape of the lens surface using a probe.

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

[0017] In the present invention, there may be an annular sealing component, the lens barrel may include the support portion, the annular portion and the second lens holding portion in sequence from the outer peripheral side to the inner peripheral side, the annular portion may include an annular opposing surface that is opposite to the image side flange surface with a gap in the optical axis direction along the optical axis, the second lens may be held in the second lens holding portion and located radially inward of the opposing surface, and the sealing component may surround the second lens from the outer peripheral side in a compressed state in the optical axis direction between the opposing surface and the image side flange surface. In this way, the sealing component may be used to seal the space connected to the first image side lens surface and the second object side lens surface. Therefore, it is possible to prevent or inhibit water vapor and the like from intruding 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 peripheral side in a state compressed in the optical axis direction between the opposing surface and the vertical surface portion. In this way, sealing can be reliably performed by the sealing member.

[0019] In the present invention, the sealing member may be an O-ring, the image side flange surface may have an ejector pin mark that contacts an ejector pin that releases the first lens from the mold when molding the first lens, and the ejector pin mark is located on the outer peripheral side of the contact portion between the O-ring and the image side flange surface. In this way, the O-ring and the ejector pin mark do not overlap, so that the O-ring can reliably perform sealing.

[0020] In the present invention, the second lens may include: a second object side lens surface facing the object side; and an object side flange surface surrounding the second object side lens surface from the outer peripheral side, 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 toward the outer peripheral side from the outer peripheral end of the second object side lens surface toward the image side, and the first annular corner portion where the first image side lens surface intersects with the inclined surface portion is located closer to the object side than the second annular corner portion where the second object side lens surface intersects with the object side inclined surface portion. In this way, it is possible to prevent or suppress the stray light that has passed through the first lens from invading the second lens via the object side inclined surface portion of the object side flange surface of the second lens and causing a ghost image. Effects of the Invention

[0021] In the lens of the present invention, the flange surface surrounding the second lens surface is provided with an inclined surface portion which is inclined from the outer peripheral end of the second lens surface toward the outer peripheral side and in a direction away from the first lens surface. Thus, the position of the outer peripheral end of the second lens surface can be set at a position close to the first lens surface, so that the tangent angle of the outer peripheral end of the second lens surface can be reduced.

[0022] In the lens unit of the present invention, an inclined surface is provided on the image side flange surface of the first lens, which is inclined from the outer peripheral end of the first image side lens surface toward the outer peripheral side and in a direction away from the first object side lens surface. As a result, the position of the outer peripheral end of the first image side lens surface can be set at a position close to the first object side lens surface, so the tangent angle of the outer peripheral end of the first image side lens surface can be reduced. In addition, since the inclined surface is provided on the image side flange surface of the first lens, which is inclined from the outer peripheral end of the first image side lens surface toward the outer peripheral side and in a direction away from the first object side lens surface, the thickness (edge ​​thickness) of the portion of the first lens supported by the support portion of the lens barrel can be made the same as that of a glass lens, and the position of the outer peripheral end of the first image side lens surface can be set at a desired position in the optical axis direction. Therefore, for a lens unit designed on the premise that the first lens uses a glass 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 This is a perspective view of a lens unit to which the present invention is applied, viewed from the object side. Figure 2 yes Figure 1 AA line section view. Figure 3 yes Figure 1 An exploded perspective view of the lens unit. Figure 4 This is a perspective view of the first lens as viewed from the image side. Figure 5 This is a partially enlarged cross-sectional view of the vicinity of the inclined surface portion of the image-side flange surface of the first lens. Figure 6 This is a diagram for explaining the manufacturing direction of the first lens. Figure 7 This is an explanatory diagram of a case where the first lens does not have an inclined surface portion on the image side flange surface. Figure 8 It is an explanatory diagram of a lens unit according to a modified example. DETAILED DESCRIPTION

[0024] Hereinafter, a lens unit according to an embodiment of the present invention will be described with reference to the drawings.

[0025] (Lens unit) Figure 1 This is a perspective view of a lens unit to which the present invention is applied, viewed from the object side. Figure 2 yes Figure 1 AA line section view. Figure 3 yes Figure 1 The lens unit 10 of this example is used for an imaging device installed in a car 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. In addition, 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] like Figure 2 As shown, 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 order from the object side X1 to the image side X2. The first lens 1 and the second lens 2 each have a negative optical power. The third lens 3 and the fourth lens 4 each have a positive optical power. The fourth lens 4 is a cemented lens, which is composed of an object side lens 5 having a negative optical power and an image side lens 6 having a positive optical power. In addition, the lens unit 10 includes a lens barrel 7 that holds these lenses 1 to 4. In addition, the lens unit 10 includes: an aperture 8 arranged between the third lens 3 and the fourth lens 4; and an infrared cut filter 9 arranged 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 a viewing angle of more than 180°. 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. Figure 2 As shown, the outer diameter of the first lens 1 is larger than that of the second lens 2, the third lens 3 and the fourth lens 4. The outer diameters of the second lens 2, the third lens 3 and the fourth lens 4 decrease in sequence.

[0028] The lens barrel 7 includes: a first lens barrel portion 15; a second lens barrel portion 16 located on the inner peripheral 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 holding portion 21 provided at an end portion on the object side X1 of the first lens barrel portion 15. The second lens 2 to the fourth lens 4 are stored in a stacked state on the inner peripheral 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 holding portion 21 to an end portion on the object side X1 of the second lens barrel portion 16.

[0029] like Figure 2 and Figure 3As shown, the first lens holding portion 21 includes: an annular wall portion 22, which is the end portion of the first lens 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 peripheral edge of the first lens 1 from the object side X1. The first contact portion 24 is provided by plastically deforming the front end portion of the first lens barrel portion 15 toward the inner peripheral side by riveting. Figure 2 As shown, the first lens 1 is inserted into the annular wall portion 22 , and its outer peripheral edge portion is clamped by the support portion 23 and the first contact portion 24 from both sides in the optical axis direction X, and is fixed to the first lens barrel portion 15 .

[0030] The second lens barrel 16 is provided with an annular protrusion 31 protruding toward the inner circumference at the end on the image side X2. The protrusion 31 has an annular end surface 31a facing the object side X1. In addition, the protrusion 31 is provided with an annular plate portion 32 protruding toward the inner circumference from the end on the image side X2 thereof. The inner diameter dimension of the inner circumference portion 33 of the inner circumference of the second lens barrel 16, which is closer to the object side X1 than the annular end surface 31a, increases in a step-like 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 outer peripheral edge portion of the object side lens 5 of the fourth lens 4 that protrudes further to the outer peripheral side than the image side lens 6 is placed on the annular end surface 31a, and the image side X2 portion of the image side lens 6 is arranged 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 contacting the inner peripheral surface portion 33 of the second lens barrel portion 16.

[0032] The third lens 3 is stacked on the object side X1 of the fourth lens 4 via the aperture 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. The third lens 3 is positioned in the radial direction by its outer peripheral surface contacting the inner peripheral surface portion 33 of the second lens barrel 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 peripheral surface contacting the inner peripheral surface portion 33 of the second lens barrel portion 16. In addition, a second contact portion 34 provided at the front end portion of the second lens barrel portion 16 contacts the second lens 2 from the object side X1. The second contact portion 34 is provided by plastically deforming the front end portion of the second lens barrel portion 16 toward the inner peripheral side by riveting. The second contact portion 34 prevents the second lens 2 from moving toward the object side X1. The end portion of the second lens barrel portion 16 on the object side X1 becomes a second lens holding portion 35 that holds the second lens 2.

[0034] like Figure 2 As shown, the lens barrel 7 includes 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 sequence from the outer peripheral side to the inner peripheral side. The annular portion 17 includes an annular relative surface 17a which is opposite to 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 relative surface 17a. An annular sealing component is arranged on the relative surface 17a. The sealing component is an O-ring 36. The O-ring 36 surrounds the second lens 2 from the outer peripheral side in a compressed state in the optical axis direction X between the relative surface 17a and the first lens 1.

[0035] (First lens, second lens and O-ring) Next, the first lens 1 (lens), the second lens 2, and the O-ring 36 will be described in detail. Figure 4 This is a perspective view of the first lens 1 as viewed from the image side X2. Figure 5 It 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 . Figure 6 It is an explanatory diagram of a method for manufacturing the first lens 1 .

[0036] like Figure 1 , Figure 2 , Figure 4 , Figure 5 As shown, 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 peripheral side. The second lens surface 42 and the image side flange surface 43 face the side opposite 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. Figure 2 , Figure 4 As shown, the image side flange surface 43 includes: an inclined surface portion 45 which is inclined toward 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 portion 46 which is perpendicular to the optical axis L on the outer peripheral side of the inclined surface portion 45. When viewed from the optical axis direction X, the vertical surface portion 46 partially overlaps with the outer peripheral side of the first object side lens surface 41. In addition, 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 peripheral surface 44 of the first lens 1 extends along the optical axis direction X, connecting the outer peripheral end of the first object side lens surface 41 and the outer peripheral end of the image side flange surface 43. The outer peripheral surface 44 of the first lens 1 has a predetermined width in the optical axis direction X. In this example, ink is applied to the image side flange surface 43.

[0037] like Figure 4 , Figure 5As shown, the vertical surface portion 46 and the inclined surface portion 45 of the image side flange surface 43 are adjacent in the radial direction. The inclined surface portion 45 is smoothly continuous with the vertical surface portion 46. In more detail, the inclined surface portion 45 includes: a first tapered surface portion 45a that is inclined toward the outer peripheral side from the first image side lens surface 42 toward the image side X2; a first curved surface portion 45b that is curved toward the image side X2 from the end portion of the outer peripheral side of the first tapered surface portion 45a; a second tapered surface portion 45c that is inclined toward the outer peripheral side from the end portion of the outer peripheral side 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 peripheral side from the end portion of the outer peripheral side of the second tapered surface portion 45c toward the image side X2. The end portion of the outer peripheral side of the second curved surface portion 45d is smoothly continuous with the vertical surface portion 46.

[0038] Here, if Figure 5 As shown, 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 less than 72°. The outer peripheral end of the first image side lens surface 42 is the annular first corner portion 49 where the first image side lens surface 42 and the inclined surface portion 45 of the image side flange surface 43 in the first lens 1 intersect. The tangent angle θ1 of the outer peripheral end of the first image side lens surface 42 is the angle at which the tangent line L1 of the outer peripheral end of the first image side lens surface 42 intersects with the imaginary line L2 perpendicular to the optical axis L, and is the angle from the imaginary line L2 toward the object side X1 to the tangent line L1 at a position closer to the optical axis than the outer peripheral end of the first image side lens surface 42.

[0039] In addition, if Figure 4 As shown, the first lens 1 has a gate mark 47 at a portion of the outer peripheral surface 44 in the circumferential direction. In addition, the first lens 1 has ejector pin marks 48 at a plurality of locations of the vertical surface portion 46 in the circumferential direction.

[0040] That is, Figure 6 As shown, the first lens 1 is a resin molded product formed by injecting resin into a mold cavity 52 of a mold 51. Figure 6 As shown in (a), the mold 51 for molding the first lens 1 includes a movable mold 53 and a fixed mold 54. The movable mold 53 moves forward and backward 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 the surface opposite to 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 the surface opposite to the movable mold 53. In addition, the fixed mold 54 includes a gate 55 that is connected to the mold cavity 52 in a direction orthogonal to the moving direction of the movable mold 53. In addition, the fixed mold 54 includes an ejector pin 56 for detaching the molded product from the fixed mold 54. The ejector pin 56 can protrude from the outer peripheral portion of the image side transfer surface 54a of the fixed mold 54 to the movable mold 53 side.

[0041] like Figure 6 As shown in (a), the movable mold 53 and the fixed mold 54 overlap in the moving direction Y of the movable mold 53, and a mold cavity 52 is formed therebetween. In the molding process of the first lens 1, first, resin is injected into the mold cavity 52 through the gate 55. When the resin is solidified in the mold cavity 52, as shown in FIG. Figure 6 As shown in (b), the movable mold 53 is moved away from the fixed mold 54. Then, as shown in Figure 6 As shown in (c), the ejector pin 56 is protruded from the image side transfer surface 54a of the fixed mold 54 to the movable mold 53 side, so that the molded body (first lens 1) is separated from the fixed mold 54. The gate mark 47 is a portion of the molded body connected to the gate 55. The ejector pin mark 48 is a mark where the ejector pin 56 contacts when the first lens 1 is molded.

[0042] Then, if Figure 2 As shown, 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 peripheral side; 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 peripheral side. 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, which is inclined toward the image side X2 from the outer peripheral end of the second object side lens surface 61 toward the outer peripheral side; and an object side vertical surface portion 66, which extends from the outer peripheral 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 is perpendicular to the optical axis L. The second image side flange surface 64 is in contact with the third lens 3.

[0043] Here, from Figure 2 and Figure 3 It can be seen that when the state in which the first lens 1 and the second lens 2 are held by the lens barrel 7 is observed from the optical axis direction X, the second object side lens surface 61 of the second lens 2 is located on the inner periphery of the first image side lens surface 42 of the first lens 1. Figure 5 As shown, the annular first corner 49 where the first image side lens surface 42 of the first lens 1 intersects the inclined surface 45 of the image side flange surface 43 is located closer to the object side X1 than the annular second corner 69 where the second object side lens surface 61 of the second lens 2 intersects the object side inclined surface 65 of the object side flange surface 62. Figure 2 As shown, the O-ring 36 placed on the annular portion 17 contacts the image side flange surface 43 of the first lens 1 and is compressed in the optical axis direction X. The ejector pin mark 48 is located on the outer peripheral side of the contact portion 36 a where the O-ring 36 contacts the image side flange surface 43 .

[0044] (Function and Effect) The lens unit 10 of this example has: 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 has: 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 surrounding the first image side lens surface 42 from the outer peripheral 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 has: an inclined surface portion 45 that is inclined toward 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 portion 46 that is perpendicular to the optical axis L on the outer peripheral side of the inclined surface portion 45. The lens barrel 7 has 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 peripheral side has an inclined surface portion 45 inclined toward the image side X2 from the outer peripheral end of the first image side lens surface 42 toward the outer peripheral side. Therefore, for example, compared with the case where the entire image side flange surface 43 is composed of a vertical surface perpendicular to the optical axis L and the first image side lens surface 42 extends in the optical axis direction X until it reaches the image side flange surface 43, the outer peripheral end of the first image side lens surface 42 can be set at a position P1 close to the first object side lens surface 41. As a result, the tangent line L1 of the outer peripheral end of the first image side lens surface 42 is inclined toward the object side X1 and toward the optical axis L side, so the tangent angle θ1 becomes smaller.

[0046] Figure 7 4 is an explanatory diagram of the first lens 1 in the case where the image side flange surface 43 does not have the inclined surface portion 45. Figure 7 As shown in the figure, when the image side flange surface 43 is composed of a vertical surface perpendicular to the optical axis L and the first image side lens surface 42 is extended to the image side flange surface 43 in the optical axis direction X, the outer peripheral end (first corner 49) of the first image side lens surface 42 becomes Figure 7 The position P2 shown is Figure 5 The position P1 shown is closer to the image side X2. As a result, the tangent line L1 of the outer peripheral end of the first image side lens surface 42 is close to being parallel to the optical axis L, so the tangent angle θ2 becomes larger. Figure 7 As shown in FIG. 1 , when the tangent angle θ2 increases, the angle of the first corner 49 becomes narrower. Figure 6 In the case of the lens shown in FIG. 1 , it is difficult to release the molded lens 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 peripheral side and inclined toward the image side X2 from the outer peripheral end of the first image side lens surface 42 toward the outer peripheral side, the position of the outer peripheral end of the first image side lens surface 42 can be moved toward the position P1 on the object side. Therefore, the tangent angle θ1 can be reduced. Here, if the tangent angle θ1 becomes smaller, the angle of the first corner portion 49 is enlarged, so that when manufacturing the lens, it becomes easy to release the molded body from the mold 51 (fixed mold 54).

[0048] 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 and away from the first object side lens surface 41. Figure 5 and Figure 7 It can be seen that 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 larger. Therefore, it becomes easier to release the molded lens from the mold 51 .

[0049] Here, if the angle at which the first image side lens surface 42 and the image side flange surface 43 intersect becomes larger, the inner corner K1 (see FIG. 1 ) of the first corner 49 for forming the intersection of the first image side lens surface 42 and the image side flange surface 43 in the mold 51 becomes larger. Figure 6 That is, when the angle of the first corner 49 where the first image side lens surface 42 and the image side flange surface 43 intersect is close to a right angle, the difficulty of processing the inner corner K1 of the corner formed in the mold 51 increases. In contrast, in this example, the first corner 49 where the first image side lens surface 42 and the image side flange surface 43 intersect is increased, so the processing of the inner corner K1 becomes easier, and the manufacture of the mold 51 becomes easier.

[0050] Furthermore, according to the present embodiment, since the tangent angle θ1 of the outer peripheral end of the first image side lens surface 42 can be reduced, the shape of the first image side lens surface 42 can be easily measured by bringing the 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 peripheral end of the first image side lens surface 42 can be reduced, Figure 7 As shown, when the tip of the contact portion 70a of the conical probe 70 is brought into contact with the outer peripheral end portion of the first image side lens surface 42, interference between the base end side of the contact portion 70a of the probe 70 and the end portion of the first image side lens surface 42 closer to the object side X1 than the measurement position can be avoided.

[0051] In addition, in this example, by providing the image side flange surface 43 with an inclined surface portion 45 inclined in a direction away from the first object side lens surface 41 from the outer peripheral end of the first image side lens surface 42 toward the outer peripheral side, the position P1 of the outer peripheral end of the first image side lens surface 42 can be set at a position close to the first object side lens surface 41. As a result, the tangent angle θ1 of the outer peripheral end of the first image side lens surface 42 can be reduced. Therefore, in the case of the lens unit 10 designed on the premise that the first lens 1 is a glass lens, when the first lens 1 is replaced with a resin lens having a lower refractive index than glass, even if the first image side lens surface 42 of the first lens 1 is deepened due to the difference in refractive index and the first image side lens surface 42 is close to a hemispherical shape, the tangent angle θ1 of the outer peripheral end of the first image side lens surface 42 can be reduced. In addition, since the image side flange surface 43 is provided with an inclined surface portion 45 which is inclined in a direction away from the first object side lens surface 41 from the outer peripheral end of the first image side lens surface 42 toward the outer peripheral side, the thickness (edge ​​thickness) of the portion of the first lens 1 supported by the support portion 23 of the lens barrel 7 can be made the same as that of the glass lens before replacement, and the position P1 of the outer peripheral end of the first image side lens surface 42 can be set at a desired position in the optical axis direction X. Therefore, for the lens unit 10 designed on the premise that the first lens 1 is a glass lens, it is easy to replace the 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 peripheral end of the first image side lens surface 42 is 72° or less. In this way, the first image side lens surface 42 of the first lens 1 can be easily measured by a shape measuring machine that measures the shape of the lens surface using the probe 70 .

[0053] Here, the position P1 of the outer peripheral end of the first image side lens surface 42 can be moved toward the object side X1 within a range where the effective light passing through the first lens 1 does not pass. Therefore, according to the optical design of the first lens 1, the tangent angle θ1 of the outer peripheral end 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 arbitrarily set.

[0054] In this example, the vertical surface 46 and the inclined surface 45 are adjacent to each other in the radial direction, and the inclined surface 45 is smoothly continuous with the vertical surface 46. Therefore, when the O-ring 36 contacts the image side flange surface 43, the O-ring 36 is not damaged. Ink can be easily applied to the image side flange surface 43.

[0055] In addition, the lens unit 10 of this example has an annular O-ring 36 (sealing member). The lens barrel 7 includes a support portion 23, an annular portion 17, and a second lens holding portion 35 in order from the outer peripheral side to the inner peripheral side. The annular portion 17 includes an annular opposing surface 17a that is opposite to 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 peripheral side in a compressed state in the optical axis direction X between the opposing surface 17a and the flange surface. Thus, the O-ring 36 can be used to seal the space connected to the first object side lens surface 42 and the second object side lens surface 61. Therefore, it is possible to prevent or suppress water vapor and the like from entering between the first object side lens surface 42 and the second object side lens surface 61.

[0056] In this example, the image side flange surface 43 includes an ejector pin mark 48 with which the ejector pin 56 for releasing the first lens 1 from the mold 51 contacts when the first lens 1 is molded. The ejector pin mark 48 is located on the outer peripheral side of the contact portion 36a where the O-ring 36 contacts the image side flange surface 43. Thus, the O-ring 36 does not overlap with the ejector pin mark 48, and thus the O-ring 36 can reliably perform sealing.

[0057] Moreover, 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 peripheral side. The second object side lens surface 61 is located on the inner side of the first image side lens surface 42 when viewed from the optical axis direction X. The object side flange surface 62 includes an object side inclined surface portion 65 inclined toward the outer peripheral side from the end portion of the outer peripheral side of the second object side lens surface 61 toward the image side X2. The annular first corner portion 49 where the first object side lens surface 42 intersects with the inclined surface portion 45 is located closer to the object side X1 than the annular second corner portion 69 where the second object side lens surface 61 intersects with the object side inclined surface portion 65. Therefore, it is possible to prevent or suppress the stray light that has passed through the first lens 1 from intruding into the second lens 2 via the object side inclined surface portion 65 of the object side flange surface 62 of the second lens 2 to generate a ghost image.

[0058] (Variation Example) Figure 8 3 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 45 and the vertical surface 46 in the flange surface of the first lens. Figure 8In the lens unit 10A of the modified example shown, the vertical surface portion 46 is extended to the inner peripheral side, and the O-ring 36 (sealing member) is brought into contact with the vertical surface portion 46. That is, the O-ring 36 surrounds the second lens 2 from the outer peripheral side in a state compressed in the optical axis direction X between the opposing surface 17a and the vertical surface portion 46. Here, the other structures of the lens unit 10A are the same as those of the lens unit 10. According to this example, it is possible to reliably perform sealing using the O-ring 36 (sealing member).

[0059] Here, the present technology can adopt the following configurations. (1) A lens unit comprising: a first lens; a second lens located next to the image side of the first lens; and a lens 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 surrounding the first image side lens surface from the outer peripheral 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 is inclined toward the image side from the outer peripheral end of the first image side lens surface toward the outer peripheral side; and a vertical surface portion that is perpendicular to the optical axis on the outer peripheral side of the inclined surface portion, the lens barrel having a support portion that supports the vertical surface portion from the image side.

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

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

[0062] (4) A lens unit according to any one of (1) to (3), wherein the lens unit has an annular sealing component, the lens barrel comprises the support portion, the annular portion and the second lens holding portion in order from the outer peripheral side to the inner peripheral side, the annular portion comprises an annular opposing surface which is opposed to 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 is located radially inside the opposing surface, and the sealing component surrounds the second lens from the outer peripheral side in a state compressed in the optical axis direction between the opposing surface and the flange surface.

[0063] (5) The lens unit according to (4), wherein the sealing member surrounds the second lens from the outer peripheral side in a state compressed in the optical axis direction between the opposing surface and the vertical surface portion.

[0064] (6) A lens unit according to (4) or (5), wherein the sealing component is an O-ring, and the image side flange surface has an ejector pin mark that contacts an ejector pin for demolding the first lens from a mold when the first lens is formed, and the ejector pin mark is located on the outer peripheral side of a contact portion where the O-ring contacts the image side flange surface.

[0065] (7) A lens unit according to any one of (1) to (6), wherein the second lens comprises: a second object side lens surface facing the object side; and an object side flange surface surrounding the second object side lens surface from the outer peripheral side, the second object side lens surface being located on the inner side of the first image side lens surface when viewed from the optical axis direction, the object side flange surface comprising an object side inclined surface portion inclined toward the outer peripheral side from an end portion of the outer peripheral 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 intersects the inclined surface portion is located closer to the object side than a second annular corner portion where the second object side lens surface intersects the object side inclined surface portion. 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…aperture; 9…infrared cut filter; 10…lens unit; 15…first barrel portion; 16…second barrel portion; 17…annular portion; 17a…opposite surface; 21…first lens holding portion; 22…annular wall portion; 23…support portion; 24…first contact portion; 31…protruding 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 tapered 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…mold 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; 66…object side vertical surface; 69…second corner portion; 70…probe; 70a…contact portion; L…optical axis; L1…tangent line; L2…imaginary line; P1…position of the outer peripheral end of the first image side lens surface; X…optical axis direction; X1…object side; X2…image side; θ1…tangent angle; θ2…tangent angle.

Claims

1. A lens, characterized in that: The invention comprises: a first lens surface; a second lens surface facing the opposite side of the first lens surface; and a flange surface surrounding the second lens surface from the outer peripheral side. The second lens surface has a concave shape that is recessed toward the first lens surface side. The flange surface includes: an inclined surface portion, which is inclined from the outer peripheral end of the second lens surface toward the outer peripheral side and in a direction away from the first lens surface; and a vertical surface portion, which is perpendicular to the optical axis on the outer peripheral side of the inclined surface portion. The lens is made of resin.

2. The lens according to claim 1, characterized in that A tangent angle of an outer peripheral end of the second lens surface is 72° or less.

3. The lens according to claim 1, characterized in that The vertical surface portion and the inclined surface portion are adjacent to each other in the radial direction, The inclined surface portion is smoothly continuous with the vertical surface portion.

4. A lens unit comprising: a first lens; a second lens located next to the image side of the first lens; and a lens barrel that holds the first lens and the second lens, characterized in that: 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 the outer peripheral side. The first image side lens surface has a concave shape that is recessed toward the object side. The image side flange surface includes: an inclined surface portion, which is inclined toward the image side from the outer peripheral end of the first image side lens surface toward the outer peripheral side; and a vertical surface portion, which is perpendicular to the optical axis on the outer peripheral side of the inclined surface portion. The lens barrel includes a support portion that supports the vertical surface portion from the image side.

5. The lens unit according to claim 4, characterized in that: A tangent angle of an outer peripheral end of the first image side lens surface is 72° or less.

6. The lens unit according to claim 4, characterized in that: The vertical surface and the inclined surface are adjacent to each other in the radial direction, The inclined surface portion is smoothly continuous with the vertical surface portion.

7. The lens unit according to claim 4, characterized in that: A ring-shaped sealing member, The lens barrel includes the support portion, the annular portion, and the second lens holding portion in order from the outer peripheral side to the inner peripheral side. The annular portion includes an annular opposing surface that opposes 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 holding portion and is located radially inward of the opposing surface. The sealing member surrounds the second lens from the outer peripheral side in a state compressed in the optical axis direction between the opposing surface and the image-side flange surface.

8. The lens unit according to claim 7, characterized in that: The sealing member surrounds the second lens from the outer peripheral side in a state of being compressed in the optical axis direction between the opposing surface and the vertical surface portion.

9. The lens unit according to claim 7 or 8, characterized in that: The sealing member is an O-ring, The image side flange surface has an ejector pin mark with which an ejector pin for releasing the first lens from the mold contacts when the first lens is molded. The ejector pin mark is located on the outer peripheral side of a contact portion where the O-ring contacts the image-side flange surface.

10. The lens unit according to claim 4, characterized in that: The second lens includes: a second object side lens surface facing the object side; and an object side flange surface surrounding the second object side lens surface from the outer peripheral side. When viewed from the optical axis direction along the optical axis, the second object side lens surface is located on the inner side of the first image side lens surface, The object side flange surface includes an object side inclined surface portion inclined toward the image side from an outer peripheral end portion of the second object side lens surface toward the image side. A first annular corner portion where the first image side lens surface intersects the inclined surface portion is located closer to the object side than a second annular corner portion where the second object side lens surface intersects the object side inclined surface portion.

Images