Lens and lens molding mold

Abstract

The utility model provides a lens. The lens is excellent in positioning accuracy and high in productivity. This lens is a glass press-molded article, and is provided with: an optical function section (11) having a first optical surface (12) and a second optical surface (13); a truncated-cone-shaped position reference surface (16) provided on the edge section (14), the radius of curvature of the position reference surface (16) increasing as the position reference surface (16) advances from the first optical surface side to the second optical surface side; and a volume absorption part (19) which is provided on the edge part and is positioned further inward than the outer edge (Q3) of the position reference surface in the direction orthogonal to the optical axis. Conditions (1) and (2) are satisfied when an angle (theta) of the position reference surface with respect to a plane (P) perpendicular to the optical axis, a distance (w) in a direction perpendicular to the optical axis from an outer edge (Q1) of the first optical surface to an inner edge (Q2) of the position reference surface, and a distance (d) in a direction parallel to the optical axis from the outer edge of the first optical surface to the inner edge of the position reference surface are 0 DEG < theta < 45 DEG: (1) d < w (2) d < w * tan (theta).

Description

Technical Field

[0001] The utility model relates to a lens, a lens forming mold and a manufacturing device of the lens forming mold. Background Art

[0002] A general lens has an edge at the periphery of an optical functional portion having an optical surface (lens surface), and the edge is mounted on a holding member such as a lens barrel or a lens frame. The position of the lens relative to the optical system is managed by the position in the direction of the optical axis, the position in the direction perpendicular to the optical axis (hereinafter referred to as the direction orthogonal to the optical axis), and the inclination of the optical system relative to the optical axis. For example, the edge has a plane perpendicular to the optical axis on at least one side in front and behind the optical axis direction, and the position of the lens in the direction of the optical axis is positioned based on the plane. In addition, the edge has a cylindrical outer peripheral surface surrounding the optical axis, and the position of the lens in the direction orthogonal to the optical axis is positioned based on the outer peripheral surface.

[0003] In recent years, the image pickup units mounted on portable electronic devices such as smartphones have been remarkably downsized, and lenses constituting the image pickup units are required to be small and lightweight.

[0004] Furthermore, in order to efficiently manufacture a glass lens, there is known a method of manufacturing a glass molded lens by press-molding a glass preform as a base material using a molding die (for example, Patent Documents 1 to 4).

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2005-325022;

[0008] Patent Document 2: Japanese Patent Application Publication No. 2015-147715;

[0009] Patent Document 3: Japanese Patent Application Publication No. 2017-065957;

[0010] Patent document 4: Japanese Patent Application Publication No. 2022-107530.

[0011] Problems to be solved by utility models

[0012] In order to reduce the size and weight of the lens, it is desirable to reduce the thickness of the edge portion. However, due to the following reasons, there are restrictions on the shape and structural freedom of the edge portion of the glass lens, making it difficult to reduce the thickness of the edge portion.

[0013] In a glass molded lens, a volume absorption portion is provided at the edge in order to absorb various errors related to the capacity or supply position of the glass preform, the volume of the internal space of the molding mold (mold space), etc. Since the volume absorption portion is a portion that allows shape deviation, the area of ​​the volume absorption portion in the edge cannot be used for positioning the lens relative to the retaining member. If the area for lens positioning cannot be sufficiently ensured at the edge, the position accuracy of the lens and the stability of the lens will deteriorate. Therefore, in addition to the size of the edge that can achieve high-precision positioning, the size of the volume absorption portion that absorbs errors during molding must be added, and the miniaturization of the edge is restricted.

[0014] Furthermore, in the manufacture of conventional glass mold lenses, it is difficult to form the edge portion with high precision while making the outer peripheral surface of the edge portion elongated in the optical axis direction due to the structural constraints of the molding die.

[0015] Furthermore, in the case of considering the productivity of the molding die for molding glass molded lenses, in the molding die for molding glass molded lenses in the past, the surface orientations of the portion forming the optical surface and the portion forming the peripheral surface of the edge portion are greatly different, and it is difficult to continuously form them using the same processing tool (for example, grinding tool). Thus, when manufacturing the molding die, the processing tool needs to be replaced, resulting in the problem that the accuracy of each portion of the molding die is easily deviated, and it is difficult to achieve efficient processing. Utility Model Content

[0016] The utility model is completed based on the recognition of the above problems, and its purpose is to provide a lens with excellent positioning accuracy and high productivity. In addition, the utility model aims to provide a lens molding mold and a manufacturing device of the lens molding mold that can efficiently produce such a lens.

[0017] Solutions for solving problems

[0018] The utility model is a lens, which is a glass press-molded product, characterized in that it has: an optical function part, which has a convex surface on one side facing the optical axis direction, namely a first optical surface, and a second optical surface on the other side facing the optical axis direction; a position reference surface in the shape of a truncated cone, which is arranged at the edge of the outer side of the optical function part, and the radius of curvature increases as it moves from the first optical surface side to the second optical surface side in the optical axis direction; and a volume absorption part, which is arranged at the edge and is located at a position closer to the inside in the direction orthogonal to the optical axis than the outer edge of the position reference surface, and allows shape errors associated with press molding, and the angle θ of the position reference surface relative to the surface perpendicular to the optical axis, the distance w from the outer edge of the first optical surface to the inner edge of the position reference surface in the direction perpendicular to the optical axis, and the distance d from the outer edge of the first optical surface to the inner edge of the position reference surface in the direction parallel to the optical axis, when 0°<θ<45°, meet the following conditions (1) and (2):

[0019] (1)d<w

[0020] (2)d<w·tanθ.

[0021] In addition, the utility model is a lens, which is a glass press-molded product, characterized in that it has: an optical functional portion, which has a convex surface, namely a first optical surface, on one side facing the optical axis direction, and a second optical surface on the other side facing the optical axis direction; a position reference surface in the shape of a truncated cone, which is arranged at the edge of the outer side of the optical functional portion, and the radius of curvature increases as it moves from the first optical surface side to the second optical surface side in the optical axis direction; and a volume absorption portion, which is arranged at the edge and is located at a position closer to the inside in the direction orthogonal to the optical axis than the outer edge of the position reference surface, allowing shape errors associated with press molding, and the angle θ of the position reference surface relative to the surface perpendicular to the optical axis, the distance w from the outer edge of the first optical surface to the inner edge of the position reference surface in the direction perpendicular to the optical axis, the distance d from the outer edge of the first optical surface to the inner edge of the position reference surface parallel to the optical axis, and the paraxial curvature radius R1 of the first optical surface, when the above θ is less than 90°, the following conditions (3) and condition (4) are satisfied.

[0022] (3)w·tan(θ-45°)<d<w<w·tanθ

[0023] (4)d>1.1R1·sin(θ-45°)

[0024] Preferably, the position reference plane is arranged on the outer periphery of the edge portion, and the edge portion has a curved surface with a radius of curvature that increases as it proceeds from the first optical surface side to the second optical surface side in the direction of the optical axis, or with the same radius of curvature, on the inner side of the position reference plane in the direction orthogonal to the optical axis, and the volume absorption portion is arranged at the end of the flange portion with the position reference plane as the outer peripheral surface and the curved surface as the inner peripheral surface.

[0025] The curved surface is an inner tapered surface of a truncated cone whose curvature radius increases as it moves from the first optical surface side to the second optical surface side in the optical axis direction. In this case, the position reference surface preferably has a larger inclination angle ratio with respect to a surface perpendicular to the optical axis than the inner tapered surface.

[0026] The curved surface may be a curved surface in which the radius of curvature increases as the radius of curvature advances from the first optical surface side to the second optical surface side in the optical axis direction and has a shape that is curved concavely in a cross section including the optical axis.

[0027] Preferably, there is an intermediate surface between the first optical surface and the position reference surface, and in a cross section including the optical axis, the intermediate surface is located in an area surrounded by a line segment connecting the outer edge of the first optical surface and the inner edge of the position reference surface, a straight line extending from the outer edge of the first optical surface in a direction orthogonal to the optical axis, and a straight line extending the position reference surface.

[0028] In addition, the utility model is a lens molding mold, which molds the above-mentioned lens, and is characterized by having: a mold member, which has an optical surface forming surface with a shape corresponding to the first optical surface, and a position reference surface forming surface with a shape corresponding to the position reference surface.

[0029] In addition, the utility model is a manufacturing device for manufacturing the above-mentioned lens molding mold, characterized in that it has: a grinding tool, which is cylindrical and forms both the optical surface forming surface and the position reference surface forming surface of the mold member by rotating around the central axis, and the paraxial curvature radius R1 of the first optical surface of the lens and the diameter φg of the end surface of the grinding tool satisfy the following condition (5):

[0030]

[0031] Utility Model Effect

[0032] According to the lens of the present invention, by satisfying various conditions, excellent positioning accuracy using the position reference surface can be achieved, and excellent productivity can be obtained. In addition, the lens molding mold and the manufacturing device of the lens molding mold of the present invention can efficiently produce the above-mentioned lens. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a cross-sectional view of the lens according to this embodiment.

[0034] Figure 2 This is a cross-sectional view of a portion of the lens after enlarging it.

[0035] Figure 3 This is a cross-sectional view of a molding die for press-molding the lens of this embodiment.

[0036] Figure 4 This is a cross-sectional view showing a mold for processing the lower mold of a molding die.

[0037] Figure 5 This is a cross-sectional view showing a state in which the optical surface forming surface of the lower mold is processed by a grinding tool.

[0038] Figure 6 This is a diagram for explaining the processing conditions for processing the lower die using a grinding tool.

[0039] Figure 7 This is a diagram for explaining the processing conditions for processing the lower die using a grinding tool.

[0040] Figure 8 It is a cross-sectional view showing a modified example of the flange portion of the lens.

[0041] Fig. 9 It is a cross-sectional view showing a modified example of the flange portion of the lens.

[0042] Fig.10 It is a cross-sectional view showing a modified example of the flange portion of the lens. DETAILED DESCRIPTION

[0043] Figure 1 The lens 10 shown is a glass molded lens formed by press-processing a glass material (glass preform) using a molding die 30 described later. Figure 2 This is a diagram of a part of the lens 10 magnified. The direction along the optical axis A of the lens 10 is defined as the optical axis direction, and the direction perpendicular to the optical axis A is defined as the optical axis orthogonal direction. The optical axis orthogonal direction may also be referred to as the radial direction of the lens 10.

[0044] Figure 1 and Figure 2 The shape of the lens 10 in the cross section including the optical axis A is shown. In addition, the cross section including the optical axis A refers to a cross section parallel to the optical axis A and in which the optical axis A is located. The lens 10 has rotational symmetry in which the same shape continues in the circumferential direction centered on the optical axis A, and the shape of the lens 10 in the cross section including the optical axis A is substantially the same at any position in the circumferential direction of the lens 10 (however, the deviation of the shape for error absorption in the volume absorption unit 19 described later is excluded).

[0045] The lens 10 has an optical function portion 11. A first optical surface 12 and a second optical surface 13 are formed on the optical function portion 11. The first optical surface 12 is a convex surface facing one side of the optical axis direction, i.e., a first direction A1. The second optical surface 13 is a convex surface facing the other side of the optical axis direction, i.e., a second direction A2. The first optical surface 12 and the second optical surface 13 of the lens 10 of this embodiment are both aspherical aspherical lenses. The outer edge of the first optical surface 12 (the peripheral edge in the direction orthogonal to the optical axis) is set as the optical surface outer edge Q1.

[0046] The lens 10 has an edge 14 on the outside of the optical function part 11. The edge 14 has a base 14a surrounding the optical function part 11 and a flange 14b located outside the base 14a. The base 14a is formed into an annular shape extending from the optical function part 11 in a direction generally perpendicular to the optical axis. The flange 14b protrudes in the second direction A2 relative to the base 14a and is a tapered annular portion having a predetermined inclination relative to the optical axis direction.

[0047] The edge portion 14 has an intermediate surface 15 located outside the first optical surface 12, and a position reference surface 16 located outside the intermediate surface 15 as an outer surface facing the first direction A1 side. In addition, the edge portion 14 has a flat surface 17 located outside the second optical surface 13, and an inner tapered surface 18 located outside the flat surface 17 as an outer surface facing the second direction A2 side. The intermediate surface 15 and the flat surface 17 constitute the outer surface of the base 14a. In addition, the position reference surface 16 constitutes the outer peripheral surface of the flange portion 14b, and the inner tapered surface 18 constitutes the inner peripheral surface of the flange portion 14b.

[0048] The position reference plane 16 is located at the outer periphery of the edge 14 and is in the shape of a truncated cone (the side of the truncated cone) centered at the optical axis A. The diameter of the position reference plane 16 increases as it advances in the second direction A2 (from the first optical surface 12 side to the second optical surface 13 side) in the optical axis direction. That is, the position reference plane 16 is a curved surface whose radius of curvature (the radius of curvature of a circle passing through the position reference plane 16 with the optical axis A as the center) increases as it advances in the second direction A2 in the optical axis direction. In the position reference plane 16, the boundary portion with the intermediate surface 15 is set as the position reference plane inner edge Q2, and the outer edge portion (the peripheral edge portion in the direction orthogonal to the optical axis) on the opposite side of the position reference plane inner edge Q2 is set as the position reference plane outer edge Q3. The position reference plane outer edge Q3 is located at the outermost edge in the direction orthogonal to the optical axis of the lens 10.

[0049] The intermediate surface 15 is a surface connecting the optical surface outer edge Q1 of the first optical surface 12 and the position reference surface inner edge Q2 of the position reference surface 16. The intermediate surface 15 of this embodiment is composed of an annular flat surface 15a extending from the optical surface outer edge Q1 in the direction orthogonal to the optical axis, and a tapered surface 15b extending from the flat surface 15a to the position reference surface inner edge Q2. The tapered surface 15b is a truncated cone shape (the side of the truncated cone) centered on the optical axis A, and the diameter of the tapered surface 15b increases as it advances in the second direction A2 (from the first optical surface 12 side to the second optical surface 13 side). That is, the tapered surface 15b is a curved surface whose radius of curvature (the radius of curvature of a circle passing through the tapered surface 15b with the optical axis A as the center) increases as it advances in the second direction A2 in the optical axis direction. The inclination angle of the tapered surface 15b relative to the optical axis A is greater than the inclination angle of the position reference surface 16 relative to the optical axis A. The conditions related to the shape of the intermediate surface 15 will be described later.

[0050] The flat surface 17 is a plane perpendicular to the optical axis A. The inner tapered surface 18 is a truncated cone shape (side surface of the truncated cone) centered on the optical axis A, and the diameter of the inner tapered surface 18 increases as it advances in the second direction A2 (from the first optical surface 12 side to the second optical surface 13 side) in the optical axis direction. That is, the inner tapered surface 18 is a curved surface whose radius of curvature (the radius of curvature of a circle passing through the inner tapered surface 18 with the optical axis A as the center) increases as it advances in the second direction A2 in the optical axis direction. The inner tapered surface 18 is substantially parallel to the position reference surface 16.

[0051] When the lens 10 is assembled to a holding member such as a lens barrel or a lens frame (not shown), the position reference plane 16 is brought into contact with a positioning portion (not shown) of the holding member. Since the position reference plane 16 is inclined relative to both the optical axis direction and the direction perpendicular to the optical axis, when the position reference plane 16 is brought into contact with the positioning portion of the holding member, the position of the lens 10 in the optical axis direction and the direction perpendicular to the optical axis can be determined. In addition, when the position reference plane 16 is brought into contact with the positioning portion of the holding member, the orientation of the optical axis A relative to the holding member (the inclination of the lens 10) can also be determined. Since the position reference plane 16 is located at the outer periphery of the edge 14, positioning is performed at a position away from the optical axis A, so the position and orientation of the lens 10 can be determined with high precision.

[0052] The edge portion 14 further includes a volume absorbing portion 19 between the position reference surface 16 and the inner tapered surface 18, that is, at the end of the flange portion 14b. The volume absorbing portion 19 is a portion for absorbing errors when the lens 10 is molded by a molding die 30 described later.

[0053] In the edge portion 14, the position reference surface 16 having a positioning function of the lens 10 is provided on the outer peripheral surface of the tapered flange portion 14b, and the volume absorption portion 19 having a molding error absorption function is provided at the end of the tapered flange portion 14b, so that the size of the position reference surface 16 is not restricted by the volume absorption portion 19. As a result, the positioning accuracy of the lens 10 using the position reference surface 16 can be improved. In addition, the edge portion 14 can be miniaturized and thinned.

[0054] As a lens different from the lens 10 of the present embodiment, the following type of lens is widely used, in which the edge has an optical axis orthogonal plane extending in the direction orthogonal to the optical axis, and a cylindrical outer peripheral surface centered on the optical axis A, and positioning in the optical axis direction is performed by the optical axis orthogonal plane of the edge, and positioning in the optical axis orthogonal direction is performed by the outer peripheral surface of the edge. In this type of lens, a volume absorption portion is mostly provided as an angle R portion at the junction of the optical axis orthogonal plane and the outer peripheral surface in the edge. Since the shape of the volume absorption portion is different depending on the degree of error, it cannot be used for lens positioning. That is, it is a structure in which the effective area of ​​the optical axis orthogonal plane and the outer peripheral surface used for lens positioning is reduced by the amount of the volume absorption portion. Therefore, in order to obtain the desired positioning performance, it is necessary to estimate the amount of reduction in effective area caused by the volume absorption portion, and set the size of the edge in the optical axis direction and the optical axis orthogonal direction to be large.

[0055] In contrast, in the lens 10 of the present embodiment, in the edge portion 14, the volume absorbing portion 19 is provided at the end of the flange portion 14b, and not on the extension line of the position reference plane 16 used for positioning (the outer peripheral surface of the flange portion 14b). Furthermore, the volume absorbing portion 19 is located further inward than the position reference plane outer edge Q3 of the position reference plane 16 in the direction orthogonal to the optical axis, and is located on the back side of the position reference plane 16 in the direction of the optical axis.

[0056] According to this structure, the effective area of ​​the position reference surface 16 will not be reduced by the volume absorption portion 19, and the edge portion 14 will not be enlarged in the direction orthogonal to the optical axis in order to provide the volume absorption portion 19. In addition, by concentrating the volume absorption portion 19 at the end of the flange portion 14b, the change in the expansion degree of the flange portion 14b toward the end side can be used to absorb the error during molding, so there is no need to reserve a margin for absorbing the error in the direction of the thickness of the edge portion 14 (the interval between the intermediate surface 15 and the flat surface 17, the interval between the position reference surface 16 and the inner tapered surface 18), and the edge portion 14 can be made thinner. As a result, the positioning performance using the position reference surface 16 is not impaired, and the edge portion 14 having the volume absorption portion 19 can be compactly configured.

[0057] The base 14a of the edge 14 has a flat surface 15a and a flat surface 17 on both sides of the optical axis direction, which are planes perpendicular to the optical axis A. Figure 3When the lens 10 is molded by the molding die 30, the flat surface 15a is formed by transferring the shape of a flat surface 36a which is a part of the pressing surface 34 of the lower mold 32 described later, and the flat surface 17 is formed by transferring the shape of a flat surface 40 which is a part of the pressing surface 38 of the upper mold 33 described later. If the flat surface 15a and the flat surface 17 are both planes perpendicular to the optical axis A, by examining the parallelism of the flat surface 15a and the flat surface 17, the inclination of the optical axis of the first optical surface 12 located inside the flat surface 15a and the second optical surface 13 located inside the flat surface 17 can be evaluated.

[0058] In addition, if the flat surface 15a is a plane perpendicular to the optical axis A, the optical surface forming surface 35 (refer to Figure 3 ) depth, the volume of the optical surface forming surface 35 in the lower mold 32 can be managed with high precision. Similarly, if the flat surface 17 is a plane perpendicular to the optical axis A, the optical surface forming surface 39 (refer to Figure 3 ) depth, the volume of the optical surface forming surface 39 in the upper mold 33 can be managed with high precision.

[0059] Therefore, by having flat surface 15 a and flat surface 17 which are planes perpendicular to optical axis A in base portion 14 a of edge portion 14 , the optical accuracy of first optical surface 12 and second optical surface 13 of lens 10 can be improved.

[0060] The lens 10 as an optical component has the advantages as described above. In addition, by making the position reference plane 16 of the lens 10 a conical surface inclined relative to the optical axis A, the angle difference between the first optical surface 12 and the position reference plane 16 becomes smaller. As a result, in the mold member (the lower mold 32 described later) used for press-molding the lens 10, it is easy to use a common processing tool to manufacture the part forming the first optical surface 12 and the part forming the position reference plane 16. Specifically, in the lens 10 of the above structure, by satisfying the following conditions, the productivity of the lens 10 can be improved.

[0061] like Figure 2As shown, the angle of the position reference plane 16 relative to the plane P perpendicular to the optical axis A is set to θ. Since the position reference plane 16 is a conical surface whose curvature radius increases as it advances toward the second direction A2 in the optical axis direction, 0°<θ<90°. The distance from the outer edge Q1 of the optical surface to the inner edge Q2 of the position reference plane in the direction perpendicular to the optical axis A is set to w. The distance from the outer edge Q1 of the optical surface to the inner edge Q2 of the position reference plane in the direction parallel to the optical axis A is set to d. The paraxial curvature radius of the first optical surface 12 is set to R1.

[0062] The lens 10 satisfies the following conditions (1) and (2) when 0°<θ<45° axis.

[0063] (1)d<w

[0064] (2)d <w·tanθ

[0065] The lens 10 satisfies the following conditions (3) and (4) when 45°≤θ<90°.

[0066] (3)w·tan(θ-45°)<d<w<w·tanθ

[0067] (4)d>1.1R1·sin(θ-45°)

[0068] like Figure 2 As shown, preferably, in the cross section including the optical axis A, the intermediate surface 15 of the lens 10 is included in a triangular region surrounded by the line segment La connecting the outer edge Q1 of the optical surface and the inner edge Q2 of the position reference surface, the vertical line Lb perpendicular to the optical axis A, and the extension line Lc obtained by extending the position reference surface 16. The flat surface 15a is a surface along the vertical line Lb, and the tapered surface 15b is a surface located between the line segment La and the extension line Lc, and the intermediate surface 15 satisfies this condition.

[0069] In addition, the intermediate surface between the first optical surface 12 and the position reference surface 16 is not limited to the shape of the intermediate surface 15 shown in the figure. For example, the intermediate surface can also be configured as a continuous surface with a shape close to the inclination of the line segment La in the above-mentioned area, rather than a structure divided into a flat surface 15a and a tapered surface 15b like the intermediate surface 15.

[0070] The basis of the above-mentioned conditions for the lens 10 and the relationship between the molding die 30 for molding the lens 10 and the manufacturing device for manufacturing the molding die 30 will be described in detail.

[0071] Figure 3The molding die 30 is shown. The molding die 30 is composed of a shell die 31, a lower die 32, and an upper die 33. The shell die 31 is substantially cylindrical and has an internal space surrounded by an inner peripheral surface 31a of the cylindrical surface. The central axis B of the molding die 30 is an axis that passes through the center of the inner peripheral surface 31a and extends in the vertical direction, and corresponds to the optical axis A of the lens 10 molded using the molding die 30.

[0072] The lower mold 32 has an insertion portion 32a that is inserted into the internal space of the shell mold 31 from below, and a large diameter portion 32b that is provided at the lower portion of the insertion portion 32a and has a larger diameter than the insertion portion 32a. The insertion portion 32a of the lower mold 32 can be inserted until the large diameter portion 32b abuts against the lower end surface of the shell mold 31. The upper mold 33 is inserted into the internal space of the shell mold 31 from above. The outer peripheral surface of the insertion portion 32a of the lower mold 32 and the outer peripheral surface of the upper mold 33 can slide in the vertical direction relative to the inner peripheral surface 31a of the shell mold 31, and are restricted from moving in the direction perpendicular to the central axis B. That is, in a state where the center of the lower mold 32 and the upper mold 33 are aligned with the central axis B, the lower mold 32 and the upper mold 33 can move in the vertical direction relative to the shell mold 31.

[0073] The lower mold 32 has a pressing surface 34 at the upper end of the insertion portion 32a. The pressing surface 34 has a concave optical surface forming surface 35, an intermediate surface 36 located around the optical surface forming surface 35, and a tapered surface 37 located around the intermediate surface 36. The pressing surface 34 is set to a shape that is concave relative to the upper end surface of the lower mold 32.

[0074] The upper mold 33 has a pressing surface 38 at the lower end thereof. The pressing surface 38 has a concave optical surface forming surface 39 , a flat surface 40 located around the optical surface forming surface 39 , and a tapered surface 41 located around the flat surface 40 .

[0075] When the lens 10 is molded using the molding die 30, a glass preform made of glass as a base material of the lens 10 is placed on the pressing surface 34 of the lower mold 32. The glass preform is held at a position on the central axis B by the concave shape of the optical surface forming surface 35. The lower mold 32 is held at a pressing moving end in which the large diameter portion 32b abuts against the lower end surface of the shell mold 31. The lower mold 32 is supported from below so that the insertion portion 32a does not come off the shell mold 31.

[0076] The glass preform is heated to a temperature exceeding the glass transition temperature to soften it, and is pressed downward against the upper mold 33 inserted into the shell mold 31. The glass preform is squeezed between the pressing surface 38 of the descending upper mold 33 and the pressing surface 34 of the lower mold 32 that restricts the descent, and is deformed.

[0077] When the upper die 33 is lowered to Figure 3When the pressing is performed at the end shown, the glass preform becomes a shape corresponding to the mold space between the lower mold 32 and the upper mold 33, and is molded into a lens 10 to which the surface shapes of the pressing surface 34 and the pressing surface 38 are respectively transferred. Then, after cooling to a predetermined temperature, the molding mold 30 is disassembled, and the molded lens 10 can be taken out.

[0078] The first optical surface 12 of the lens 10 is formed by the optical surface forming surface 35 of the lower mold 32 , the intermediate surface 15 of the lens 10 is formed by the intermediate surface 36 of the lower mold 32 , and the position reference surface 16 of the lens 10 is formed by the tapered surface 37 of the lower mold 32 .

[0079] The optical surface forming surface 35 is a concave surface (aspherical surface) corresponding to the convex first optical surface 12 .

[0080] The intermediate surface 36 has a flat surface 36a corresponding to the flat surface 15a of the intermediate surface 15, and a tapered surface 36b corresponding to the tapered surface 15b. The flat surface 36a is a plane perpendicular to the central axis B. The tapered surface 36b is a truncated cone shape (a side surface of a truncated cone) centered on the central axis B, and the diameter of the tapered surface 36b increases as it moves toward the top end side (upper side) of the insertion portion 32a of the lower mold 32.

[0081] The tapered surface 37 is in the shape of a truncated cone (side surface of a truncated cone) centered on the central axis B, and the diameter of the tapered surface 37 increases toward the tip side (upper side) of the insertion portion 32 a of the lower mold 32 .

[0082] The second optical surface 13 of the lens 10 is formed by the optical surface forming surface 39 of the upper mold 33 , the flat surface 17 of the lens 10 is formed by the flat surface 40 of the upper mold 33 , and the inner tapered surface 18 of the lens 10 is formed by the tapered surface 41 of the upper mold 33 .

[0083] The optical surface forming surface 39 is a concave surface (aspherical surface) corresponding to the convex second optical surface 13 .

[0084] The flat surface 40 is a plane perpendicular to the central axis B.

[0085] The tapered surface 41 is in the shape of a truncated cone (side surface of a truncated cone) centered on the central axis B, and the diameter of the tapered surface 41 decreases toward the tip side (downward) of the upper die 33 .

[0086] When the lens 10 is manufactured using the molding die 30 , various errors may occur, such as a capacity error of the glass preform, a volume error of the mold space inside the molding die 30 , and a deviation in the supply position of the glass preform.

[0087] exist Figure 3At the respective pressing moving ends of the lower mold 32 and the upper mold 33 shown, there is a gap 42 at the periphery of the pressing surface 34 and the pressing surface 38. At the location of the gap 42, the shape of the glass preform during molding is allowed to change, and the shape of the lens 10 changes according to the above-mentioned various errors. The part that allows the deviation of the shape corresponding to the gap 42 is the volume absorption part 19 of the edge 14 of the lens 10. Therefore, Figure 1 and Figure 2 The shape of the volume absorbing portion 19 shown is an example, and the shape of the volume absorbing portion 19 varies depending on the degree of error. In addition, by providing the volume absorbing portion 19, other portions of the lens 10 can be formed with high precision.

[0088] The lower mold 32 and the upper mold 33 are made of, for example, ceramics or superhard alloy so as to have sufficient durability in a high temperature environment during lens molding. Figure 4 The step of forming the pressing surface 34 of the lower mold 32 by the manufacturing apparatus for manufacturing the lens molding die is shown. The pressing surface 34 is formed by grinding using the grinder 50 constituting the manufacturing apparatus.

[0089] The grinding tool 50 is cylindrical and can rotate about the central axis of the cylindrical shape, that is, the rotation axis C. In the manufacturing device, the angle of the rotation axis C can be changed. The grinding tool 50 is brought into contact with the lower mold 32 with the corner portion of the boundary between the end surface 50a and the side surface 50b as the processing point S, and performs grinding while rotating about the rotation axis C.

[0090] like Figure 4 and Figure 5 As shown, when the optical surface forming surface 35 of the pressed surface 34 is formed by grinding using a grinder 50, the rotation axis C is usually tilted 45° relative to the normal K of the optical surface forming surface 35 at the position in contact with the processing point S. When grinding is performed by such a method, it is preferred that the diameter of the grinder 50, that is, the grinder diameter φg (the diameter of the end surface 50a in the direction perpendicular to the rotation axis C) satisfies the following condition (5). R1 ​​is the paraxial curvature radius of the first optical surface 12 of the lens 10 described above. Since the shape of the optical surface forming surface 35 is transferred to become the first optical surface 12, R1 is included in the size condition of the grinder 50 that forms the optical surface forming surface 35.

[0091]

[0092] By satisfying condition (5), the grinding tool 50 can process the optical surface forming surface 35 without interfering with the lower mold 32 at locations other than the processing point S. In addition, the smaller the grinding tool diameter φg is, the less likely it is that the grinding tool 50 will interfere with other parts of the lower mold 32. However, on the other hand, since the shape error of the optical surface forming surface 35 is likely to occur, it is preferred to use a grinding tool diameter φg as large as possible within the range of condition (5). In this embodiment, a grinding tool 50 with φg=1.1R1 is used.

[0093] The pressing surface 34 of the lower mold 32 includes an optical surface forming surface 35, an intermediate surface 36, and a tapered surface 37. Among them, the optical surface forming surface 35 and the tapered surface 37 require particularly strict accuracy. The optical surface forming surface 35 is a portion that forms the first optical surface 12, and the surface accuracy of the optical surface forming surface 35 is directly related to the optical performance of the lens 10. The tapered surface 37 is a portion that forms the position reference surface 16, and the surface accuracy of the tapered surface 37 has a great influence on the position accuracy of the lens 10.

[0094] Here, if the same grinding tool 50 is used to form the optical surface forming surface 35 and the tapered surface 37, there are multiple advantages. First, when manufacturing the pressed surface 34, it is not necessary to replace the processing tool at each forming position, and the production efficiency is improved. In addition, since the same grinding tool 50 is used to form, it is easy to perform overall precision management on the pressed surface 34 including the optical surface forming surface 35 and the tapered surface 37.

[0095] On the other hand, when each part of the pressed surface 34 is formed by the same mold 50, it is necessary to consider the possibility of the mold 50 interfering with the lower mold 32 at a position other than the processing point S. In particular, in the pressed surface 34 having a shape in which the center portion passing through the center axis B is the deepest and the outer peripheral side away from the center axis B is shallow, when the tapered surface 37 on the outer peripheral side is formed after the optical surface forming surface 35 on the center side is formed, it is required that the mold 50 does not contact the optical surface forming surface 35 at the stage of forming the tapered surface 37.

[0096] Figures 5 to 7 This is an enlarged cross-sectional view of the pressing surface 34 of the lower mold 32 and the mold 50 (including the cross section of the central axis B). Figures 5 to 7 Although the shape of the pressed surface 34 after completion is shown in FIG. 5 , in reality, since the processing using the mold 50 is performed in stages, each part of the pressed surface 34 is completed in sequence. For example, when processing is performed from the center side toward the peripheral side of the pressed surface 34, Figure 5 In the processing stage of the optical surface forming surface 35 shown, the intermediate surface 36 and the tapered surface 37 are not completed.

[0097] Since the first optical surface 12, the intermediate surface 15, and the position reference surface 16 of the lens 10 transfer the shape of the pressing surface 34 of the lower mold 32, the description of the conditions of the lower mold 32 is also described using the same elements (w, d, θ, R1, La, Lb, Ld) as those of the above-mentioned conditions of the lens 10. In addition, the central axis B in the description of the lower mold 32 is synonymous with the optical axis A reflected in the condition of the lens 10.

[0098] On the pressed surface 34, the outer edge of the optical surface forming surface 35 is defined as the optical surface forming surface outer edge Q11. In addition, the boundary portion of the tapered surface 37 with the intermediate surface 36 (tapered surface 36b) is defined as the tapered surface inner edge Q12, and the outer edge portion on the opposite side of the tapered surface inner edge Q12 is defined as the tapered surface outer edge Q13. The optical surface forming surface outer edge Q11 is a portion corresponding to the optical surface outer edge Q1 of the lens 10, the tapered surface inner edge Q12 is a portion corresponding to the position reference surface inner edge Q2 of the lens 10, and the tapered surface outer edge Q13 is a portion corresponding to the position reference surface outer edge Q3 of the lens 10.

[0099] The distance perpendicular to the central axis B (optical axis A) from the outer edge Q11 of the optical surface forming surface to the inner edge Q12 of the tapered surface is set as w. The distance parallel to the central axis B (optical axis A) from the outer edge Q11 of the optical surface forming surface to the inner edge Q12 of the tapered surface is set as d. The angle formed by the line segment La connecting the outer edge Q11 of the optical surface forming surface and the inner edge Q12 of the tapered surface and the vertical line Lb perpendicular to the central axis B (optical axis A) is set as ψ. The angle formed by the tapered surface 37 and the vertical line Lb is set as θ.

[0100] exist Figures 5 to 7 In the cross section shown (the cross section including the central axis B), the intermediate surface 36 of the lower mold 32 is included in a triangular region surrounded by the line segment La, the vertical line Lb, and the extended line Lc obtained by extending the tapered surface 37. The flat surface 36a is a surface along the vertical line Lb, and the tapered surface 36b is a surface located between the line segment La and the extended line Lc. The intermediate surface 36 satisfies this condition. Furthermore, the intermediate surface 15 (flat surface 15a, tapered surface 15b) of the lens 10 corresponding to the intermediate surface 36 is also included in the triangular region.

[0101] Unlike the intermediate surface 36, if the optical surface forming surface 35 and the conical surface 37 are connected via a surface passing through the outside of the above-mentioned area, the shape processing between the optical surface forming surface 35 and the conical surface 37 becomes complicated (for example, it is necessary to use a processing tool other than the mold 50), and interference between the mold 50 and the lower mold 32 is likely to occur.

[0102] Here, the pressing surface 34 of the lower mold 32 preferably satisfies the following conditions (6) and (7).

[0103] (6)ψ<45°

[0104] 7)ψ<θ

[0105] By satisfying conditions (6) and (7) for the inclination of the line segment La, which is one side of the set area of ​​the intermediate surface 36, it is possible to prevent the mold 50 from interfering with part of the intermediate surface 36 when the tapered surface 37 is formed using the mold 50. In the case of ψ ≥ 45° outside the range of condition (6) and in the case of ψ ≥ θ outside the range of condition (7), the judgment of whether the mold 50 interferes with the lower mold 32 (intermediate surface 36) becomes complicated.

[0106] Next, regarding the inclination of the tapered surface 37, the case of 0°<θ<45° ( Figure 6 ) and 45°≤θ<90°( Figure 7 In either case, when the tapered surface 37 is formed by the mold 50, the processing is performed in a state where the side surface 50b (rotation axis C) of the mold 50 is tilted 45° relative to the finished shape of the tapered surface 37 in the cross section including the central axis B of the forming die 30.

[0107] like Figure 6 and Figure 7 As shown in the figure, when the tapered surface 37 is formed in the range from the tapered surface inner edge Q12 to the tapered surface outer edge Q13, when the processing point S where the mold 50 contacts the lower mold 32 is the tapered surface inner edge Q12, the end surface 50a of the mold 50 is located at the bottom (near the optical surface forming surface 35), forming a situation where interference with the lower mold 32 is likely to occur. Therefore, it is sufficient to confirm whether there is interference between the mold 50 and the lower mold 32 at a position other than the processing point S at least when the processing point S is the tapered surface inner edge Q12.

[0108] [When 0°<θ<45°]

[0109] like Figure 6 As shown, in the case of 0°<θ<45°, if the rotation axis C (side surface 50b) of the mold 50 is tilted 45° relative to the finished shape of the tapered surface 37, when the processing point S is located at the tapered surface inner edge Q12, the farthest point T in the end surface 50a of the mold 50, which is farthest from the processing point S, is located above the processing point S (in the direction away from the pressing surface 34 along the center axis B). That is, the end surface 50a of the mold 50 is tilted in the direction away from the pressing surface 34 with the processing point S as the base end. Moreover, while the mold 50 processes the tapered surface 37 in the range from the tapered surface inner edge Q12 to the tapered surface outer edge Q13, the processing point is always at the lowest position in the end surface 50a, and the mold 50 does not contact the lower mold 32 at a portion other than the processing point S. Therefore, in the case of 0°<θ<45°, it is sufficient as long as at least the above conditions (6) and (7) are satisfied.

[0110] [When 45°≤θ<90°]

[0111] like Figure 7 As shown in the figure, when 45°≤θ<90°, if the rotation axis C (side surface 50b) of the mold 50 is tilted 45° relative to the finished shape of the tapered surface 37, the farthest point T in the end surface 50a of the mold 50, which is farthest from the processing point S, is located below the processing point S (in the direction close to the pressing surface 34 along the central axis B) when the processing point S is located at the inner edge Q12 of the tapered surface. That is, the end surface 50a of the mold 50 is tilted in the direction close to the pressing surface 34 with the processing point S as the base end. At this time, the following conditions are set so that the farthest point T does not interfere with the lower mold 32 (especially the optical surface forming surface 35).

[0112] When the rotation axis C of the grinding tool 50 is inclined 45° relative to the finished shape of the tapered surface 37, the angle between the end face 50a of the grinding tool 50 and the vertical line Lb perpendicular to the central axis B is θ-45°. The distance χ between the processing point S and the farthest point T in the direction along the central axis B (optical axis direction) is χ=φg·sin(θ-45°).

[0113] Here, by satisfying the following condition (8), the farthest point T can be prevented from contacting the lower die 32 when the processing point S is located at the inner edge Q12 of the tapered surface, thereby avoiding interference between the mold 50 and the lower die 32 .

[0114] (8)d>χ

[0115] When condition (8), i.e., d≤χ, is not satisfied, since the position of the farthest point T in the direction along the center axis B (optical axis direction) is lower than the outer edge Q11 of the optical surface forming surface (close to the lower mold 32 side), the mold 50 may interfere with the optical surface forming surface 35 of the lower mold 32.

[0116] In addition, when 45°≤θ<90°, when the processing point S is located at the inner edge Q12 of the tapered surface, it is also necessary to consider the interference between the mold 50 and the lower mold 32 near the processing point S. Near the processing point S, if there is a gap between the end surface 50a of the mold 50 and the line segment La, the mold 50 and the lower mold 32 (especially the intermediate surface 36) do not interfere.

[0117] Here, by satisfying the following condition (9), a clearance angle can be provided between the end face 50a of the mold 50 and the line segment La near the processing point S, thereby preventing the end face 50a from interfering with the lower mold 32 (particularly the intermediate surface 36).

[0118] (9)θ-45°<ψ

[0119] Summarizing the above conditions, the results are as follows. When 0°<θ<45°, it is sufficient to satisfy condition (6) ψ<45° and condition (7) ψ<θ. Based on condition (6), d<w of condition (1) is derived. Based on condition (7), d<w·tanθ of condition (2) is derived.

[0120] Therefore, when 0°<θ<45°, by satisfying condition (1) d<w and condition (2) d<w·tanθ, the pressing surface 34 of the lower mold 32 including the optical surface forming surface 35 and the tapered surface 37 can be formed using the common mold 50. Furthermore, in the lens 10 to which the shape of the pressing surface 34 of the lower mold 32 is transferred, a shape satisfying both conditions (1) and (2) can be formed.

[0121] When 45°≤θ<90°, in addition to ψ<45° of condition (6) and ψ<θ of condition (7), θ-45°<ψ of condition (9) is added. Based on these conditions, θ-45°<ψ<45°<θ is obtained, and w·tan(θ-45°)<d<w<w·tanθ of the above condition (3) is derived.

[0122] In addition, when it is less than 45°≤θ<90°, for the grinding tool diameter φg of the grinding tool 50, when φg of condition (5) is φg=1.1R1 according to bar R1, d>χ of condition (8) can be deduced, and d>1.1R1·sin(θ-45°) of the above condition (4) can be derived.

[0123] Therefore, when 45°≤θ<90, by satisfying w·tan(θ-45°)<d<w<w·tanθ1 of condition (3) and satisfying d>1.1R1·sin(θ-45°) of condition (4), it is possible to form the pressing surface 34 of the lower mold 32 including the optical surface forming surface 35 and the tapered surface 37 using the common mold 50. Furthermore, in the lens 10 to which the shape of the pressing surface 34 of the lower mold 32 is transferred, a shape satisfying both conditions (3) and (4) can be formed.

[0124] As described above, in this embodiment, for the lens 10 positioned using the tapered position reference surface 16 inclined relative to the optical axis direction and the direction perpendicular to the optical axis, and the molding die 30 (lower mold 32) for press-molding the lens 10, by satisfying the above-mentioned conditions, the pressing surface 34 including the optical surface forming surface 35 and the tapered surface 37 can be formed using the same mold 50. Thus, the lower mold 32 can be manufactured efficiently, which can contribute to improving the productivity of the lens 10 molded using the molding die 30.

[0125] In addition, the lens of the present invention is not limited to the above-mentioned embodiment, and can be changed within the scope of the gist of the present invention. Figure 1 and Figure 2 In the lens 10 shown, the position reference surface 16 constituting the outer peripheral surface of the flange portion 14 b is substantially parallel to the inner tapered surface 18 constituting the inner peripheral surface of the flange portion 14 b , but the present invention is not limited to this structure.

[0126] Figure 8 A modified example of the flange portion 14 b of the edge portion 14 of the lens 10 is shown. Figure 8 The flange portion 14b shown has an inner tapered surface 20 in a truncated cone shape centered on the optical axis A as an inner peripheral surface located on the inner side of the position reference surface 16 in the direction orthogonal to the optical axis. Like the inner tapered surface 18 of the above-mentioned embodiment, the inner tapered surface 20 is a curved surface whose radius of curvature (the radius of curvature of a circle centered on the optical axis A and passing through the inner tapered surface 20) increases as it advances in the second direction A2 (from the first optical surface 12 side to the second optical surface 13 side) in the optical axis direction.

[0127] As a difference from the above-mentioned embodiment, the inner tapered surface 20 is not parallel to the position reference surface 16, and the inclination angle θ1 of the position reference surface 16 relative to the plane P perpendicular to the optical axis A and the inclination angle θ2 of the inner tapered surface 20 relative to the plane P perpendicular to the optical axis A are in a relationship of θ1>θ2. That is, the flange portion 14b has a tapered shape in which the distance between the position reference surface 16 and the inner tapered surface 20, i.e., the thickness decreases as it moves from the inner edge side connected to the base 14a toward a certain outer edge (top end) side of the volume absorption portion 19. By configuring the flange portion 14b in this way, when the lens 10 is demolded after being press-molded using the molding die 30, it is possible to suppress the lens 10 from sticking to the upper mold 33, thereby achieving an effect of improving demolding properties.

[0128] Fig. 9 Another modified example of the flange portion 14 b of the edge portion 14 of the lens 10 is shown. Fig. 9 The flange portion 14b shown has an inner curved surface 21, which constitutes an inner peripheral surface located on the inner side of the optical axis orthogonal direction relative to the position reference surface 16. Like the inner tapered surface 18 and the inner tapered surface 20 described above, the inner curved surface 21 is a curved surface whose radius of curvature (the radius of curvature of a circle centered on the optical axis A and passing through the inner curved surface 21) increases as it advances in the second direction A2 (from the first optical surface 12 side to the second optical surface 13 side) in the optical axis direction.

[0129] like Fig. 9 As shown, the inner curved surface 21 also has a concave shape in the cross section including the optical axis A. Furthermore, the inner curved surface 21 has no step or bend between the inner curved surface 21 and the flat surface 17 , and the inner curved surface 21 and the flat surface 17 are smoothly connected.

[0130] Different from Fig. 9 The inner curved surface 21 shown, Figure 1 The inner tapered surface 18 of the flange portion 14b shown in FIG. Figure 8 The inner tapered surface 20 of the flange portion 14 b shown is a curved surface (side surface of a truncated cone) having the optical axis A as the center, and is a straight line in a cross section including the optical axis A.

[0131] The inner curved surface 21 may be an arc shape with a constant radius of curvature or a non-arc curved shape with a variable radius of curvature in the cross section including the optical axis A. In the case of an arc shape with a constant radius of curvature in the cross section including the optical axis A, the inner curved surface 21 is a concave annular surface.

[0132] In the structure where the flange portion 14b of the edge portion 14 has the inner curved surface 21, the inner curved surface 21 and the flat surface 17 are smoothly connected without any steps or bends. Therefore, the load is less likely to be concentrated on the boundary between the flat surface 17 and the inner curved surface 21, that is, the boundary between the base portion 14a and the flange portion 14b, which is conducive to ensuring the strength of the lens 10. In addition, when the glass preform is pressed to manufacture the lens 10, it is easy to make the glass flow smoothly from the base portion 14a to the flange portion 14b, thereby achieving the effect of improving the molding accuracy of the lens 10.

[0133] In addition, since there are no steps or bends between the area for forming the flat surface 17 and the area for forming the inner curved surface 21 on the pressing surface of the molding die (upper die), when manufacturing the pressing surface of the molding die (upper die), processing tools such as grinding tools can be moved in a smooth moving trajectory, thereby performing high-precision and efficient manufacturing.

[0134] Furthermore, when the inner curved surface 21 is an arc shape with a fixed radius of curvature in the cross section containing the optical axis A, when manufacturing the area for forming the inner curved surface 21 on the pressing surface of the molding mold (upper mold), the movement trajectory and movement direction of the processing tool become simple, which can improve the manufacturing efficiency of the molding mold.

[0135] Fig.10 Still another modified example of the flange portion 14 b of the edge portion 14 of the lens 10 is shown. Fig.10The flange portion 14b shown has an inner curved surface 22, and the inner curved surface 21 constitutes an inner peripheral surface located on the inner side of the position reference surface 16 in the direction orthogonal to the optical axis. The inner curved surface 22 is different from the inner conical surface 18, the inner conical surface 20, and the inner curved surface 21 described above, and is substantially parallel to the optical axis A, and is a cylindrical surface centered on the optical axis A. That is, in the inner curved surface 22, the radius of curvature (the radius of curvature of a circle centered on the optical axis A and passing through the inner curved surface 22) does not change as it advances in the second direction A2 (from the first optical surface 12 side to the second optical surface 13 side) in the optical axis direction, and the radius of curvature is the same at any position in the optical axis direction.

[0136] The inner curved surface 22 of such a shape can be used as a position reference in the direction perpendicular to the optical axis. For example, in an optical system including the lens 10, when optical elements other than the lens 10 (other lenses, spacers for determining the position of the lens, etc.) are arranged, the other optical elements can be brought into contact with the inner curved surface 22 of the lens 10 to determine the position in the direction perpendicular to the optical axis. Since the lens 10 is positioned relative to the holding member (not shown) via the position reference surface 16, the other optical elements are positioned via the lens 10.

[0137] As shown in the above-mentioned embodiments and variations, the structural examples of the inner circumferential surface of the flange portion 14b that is located on the inner side of the position reference surface 16 in the direction orthogonal to the optical axis are roughly divided into: a curved surface (inner conical surface 18, inner conical surface 20, inner curved surface 21) whose radius of curvature increases as it advances in the second direction A2 (from the first optical surface 12 side to the second optical surface 13 side) in the direction of the optical axis; and a curved surface (inner curved surface 22) whose radius of curvature does not change as it advances in the second direction A2 (from the first optical surface 12 side to the second optical surface 13 side) in the direction of the optical axis. In this way, a variety of structures can be selected for the inner circumferential surface of the flange portion 14b, and the most suitable shape can be used according to the conditions of importance. In addition, Figures 8 to 10 The lens 10 of each modified example shown satisfies the requirements of the lens 10 ( Figure 1 and Figure 2 ) of the conditions that have been determined.

[0138] Although the first optical surface 12 and the second optical surface 13 of the lens 10 in the above embodiment are both aspherical lenses, the lens of the present invention is not limited to aspherical lenses, but can also be applied to spherical lenses. In addition, the second optical surface 13 can also be a concave surface instead of a convex surface.

[0139] The implementation of the utility model is not limited to the above-mentioned implementation and its variants, and various changes, substitutions, and deformations can be made within the scope of the main idea of ​​the utility model. In addition, if the technical idea of ​​the utility model can be realized by other methods based on technological progress or other derived technologies, the method can also be used for implementation. Therefore, the scope of the patent claims covers all implementations that still fall within the scope of the technical idea of ​​the utility model.

[0140] Description of Reference Numerals

[0141] 10: Lens;

[0142] 11: Optical function part;

[0143] 12: first optical surface;

[0144] 13: Second optical surface;

[0145] 14: margin;

[0146] 14a: base;

[0147] 14b: flange portion;

[0148] 15: middle surface;

[0149] 15a: flat surface;

[0150] 15b: cone surface;

[0151] 16: Position reference plane;

[0152] 17: Flat surface;

[0153] 18: medial cone;

[0154] 19: volume absorption part;

[0155] 20: medial cone;

[0156] 30: molding mold (lens molding mold);

[0157] 31: Shell mold;

[0158] 32: lower mold (mold component);

[0159] 33: Upper mold;

[0160] 34: pressed surface;

[0161] 35: Optical surface forming surface;

[0162] 36: middle surface;

[0163] 36a: flat surface;

[0164] 36b: cone surface;

[0165] 37: cone surface;

[0166] 38: pressed surface;

[0167] 39: Optical surface forming surface;

[0168] 40: flat surface;

[0169] 41: cone;

[0170] 42: gap;

[0171] 50: Grinding tool (manufacturing device for lens molding mold);

[0172] 50a: end face of the grinding tool;

[0173] A: optical axis;

[0174] B: The center axis of the molding die;

[0175] C: Rotation axis of the abrasive tool;

[0176] Q1: outer edge of the optical surface;

[0177] Q2: Inner edge of position reference surface;

[0178] Q3: Outer edge of position reference surface;

[0179] Q11: The outer edge of the optical surface formation surface;

[0180] Q12: Inner edge of cone;

[0181] Q13: outer edge of cone;

[0182] S: processing point;

[0183] T: farthest point;

[0184] φg: Grinding tool diameter.

Claims

1. A lens, which is a pressed glass product, characterized in that: have: An optical function portion having a convex surface on one side facing the optical axis direction, namely a first optical surface, and a second optical surface on the other side facing the optical axis direction; a position reference surface in the shape of a truncated cone, which is provided at an edge portion of an outer side of the optical function portion, and whose curvature radius increases as it progresses from the first optical surface side to the second optical surface side in the optical axis direction; and The volume absorbing portion is provided at the edge portion and is located at a position that is further inward than the outer edge of the position reference surface in the direction perpendicular to the optical axis, and allows for shape errors associated with press molding. The angle θ of the position reference plane relative to the plane perpendicular to the optical axis, the distance w from the outer edge of the first optical surface to the inner edge of the position reference plane in the direction perpendicular to the optical axis, and the distance d from the outer edge of the first optical surface to the inner edge of the position reference plane in the direction parallel to the optical axis, when 0°<θ<45°, satisfy the following conditions (1) and (2): (1)d<w (2)d<w·tanθ.

2. A lens, which is a pressed glass product, characterized in that: have: An optical function portion having a convex surface on one side facing the optical axis direction, namely a first optical surface, and a second optical surface on the other side facing the optical axis direction; a position reference surface in the shape of a truncated cone, which is provided at an edge portion of an outer side of the optical function portion, and whose curvature radius increases as it progresses from the first optical surface side to the second optical surface side in the optical axis direction; and The volume absorbing portion is provided at the edge portion and is located at a position that is further inward than the outer edge of the position reference surface in the direction perpendicular to the optical axis, and allows for shape errors associated with press molding. The angle θ of the position reference plane relative to the plane perpendicular to the optical axis, the distance w from the outer edge of the first optical surface to the inner edge of the position reference plane in the direction perpendicular to the optical axis, the distance d from the outer edge of the first optical surface to the inner edge of the position reference plane parallel to the optical axis, and the paraxial curvature radius R1 of the first optical surface, when 45°≤θ<90°, satisfy the following conditions (3) and (4): (3)d<w·tan(θ-45°)<d<w<w·tanθ (4)d>1.1R1·sin(θ-45°).

3. The lens according to claim 1 or 2, characterized in that: The position reference surface is provided at the outer periphery of the edge portion, The edge portion has a curved surface whose radius of curvature increases as it goes from the first optical surface side to the second optical surface side in the optical axis direction, or has a constant radius of curvature, on the inner side of the position reference surface in the direction orthogonal to the optical axis. The volume absorbing portion is provided at an end portion of a flange portion having the position reference surface as an outer peripheral surface and the curved surface as an inner peripheral surface.

4. The lens according to claim 3, characterized in that The curved surface is an inner tapered surface of a truncated cone shape whose curvature radius increases as it advances from the first optical surface side to the second optical surface side in the optical axis direction.

5. The lens according to claim 4, characterized in that: The position reference surface has a larger inclination angle with respect to a surface perpendicular to the optical axis than the inner tapered surface.

6. The lens according to claim 3, characterized in that The curved surface is a curved surface in which the radius of curvature increases as the radius of curvature advances from the first optical surface side to the second optical surface side in the optical axis direction and has a shape that is curved concavely in a cross section including the optical axis.

7. The lens according to claim 1 or 2, characterized in that: An intermediate surface is provided between the first optical surface and the position reference surface, In a cross section including the optical axis, the intermediate surface is located in an area surrounded by a line segment connecting the outer edge of the first optical surface and the inner edge of the position reference plane, a straight line extending from the outer edge of the first optical surface in a direction orthogonal to the optical axis, and a straight line extending the position reference plane.

8. A lens molding mold, comprising an upper mold and a lower mold, wherein the lens according to claim 1 or 2 is molded by transferring the shapes of the pressing surfaces of the upper mold and the lower mold to a glass preform, wherein: The pressing surface of the lower mold has a first optical surface forming surface having a shape capable of transferring the first optical surface, and a position reference surface forming surface having a shape capable of transferring the position reference surface.

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