Lens and lens forming die

Abstract

The utility model provides a lens which can ensure optical performance and keep part of the lens small and light. The lens is provided with: an optical function section (41) which is a press-molded product of glass, has lens surfaces (43, 44) on both sides in the optical axis direction, and has volume absorption sections (46, 47) around the lens surfaces, said volume absorption sections allowing shape errors associated with press molding; and a flange section (42) which is coupled to the optical function section and is made of a material different from that of the glass of the optical function section, the flange section having: a cylindrical section (42a) which is formed in a cylindrical shape centered on the optical axis and which is fixed so as to surround the outer peripheral surface of the optical function section; and an annular portion (42b) having a thickness in the optical axis direction smaller than the length of the cylinder portion in the optical axis direction and extending from the outer peripheral surface of the cylinder portion in the direction orthogonal to the optical axis, the length L of the cylinder portion in the optical axis direction and the width W of the annular portion in the direction orthogonal to the optical axis satisfying W / L > = 0.8.

Description

Technical Field

[0001] The utility model relates to a lens and a lens forming mold. Background Art

[0002] In recent years, it has become common to mount camera units on portable electronic devices such as smartphones, and the demand for making the camera units small and high-performance has also increased. In addition, the lens constituting the camera unit is required to meet the requirements of high optical performance, high-precision positioning of the holding member holding the lens, and to be as small and light as possible.

[0003] Usually, the lens has a lens surface, and has a flange portion at the periphery of the main body portion that performs the optical function, so that the flange portion is fixed to a retaining member and the position is specified. The position of the lens is managed according to the position in the optical axis direction, the position in the direction perpendicular to the optical axis, and the inclination relative to the optical axis of the optical system. For example, the flange portion has a plane perpendicular to the optical axis on at least one side in front and behind the optical axis direction. The position of the lens in the optical axis direction is specified based on this plane. In addition, the flange portion has a cylindrical outer peripheral surface surrounding the optical axis, and sometimes the position of the lens in the direction perpendicular to the optical axis (hereinafter referred to as the direction orthogonal to the optical axis) is specified based on this outer peripheral surface.

[0004] As another method of positioning the lens, it is also carried out as follows: the flange portion has a conical surface that is neither parallel to the optical axis nor perpendicular to the optical axis (that is, a conical surface inclined relative to the optical axis), and the position in the direction of the optical axis and the position in the direction orthogonal to the optical axis are managed together with this conical surface as a reference.

[0005] As part of miniaturization and lightening of the lens, it is desirable to reduce the thickness of the flange in the optical axis direction. However, due to the following reasons, there are restrictions on the shape and structural freedom of the flange of the glass lens, making it difficult to reduce the thickness of the flange sufficiently.

[0006] When a glass preform is pressed and molded by a molding die to manufacture a glass molded lens, a volume absorption portion is provided on the flange portion in order to absorb various errors related to the capacity of the glass preform, the supply position, the volume of the internal space (mold space) of the molding die, etc. The volume absorption portion is a portion that allows shape deviations corresponding to the above-mentioned various errors. In more detail, by setting a rounded corner portion as a curved shape in the volume absorption portion, the shape of the rounded corner portion is changed, thereby absorbing the above-mentioned various errors. The radius of curvature of the rounded corner portion of the volume absorption portion is used as the R angle value of the corner. The R angle value of the corner is set to be the minimum allowable value at the lower limit of the volume of the mold space of the changing molding die (within the range of the allowable error, the volume of the mold space is the smallest) and at the upper limit of the volume of the changing glass preform (within the range of the allowable error, the volume of the glass preform is the largest). In addition, the R angle value of the corner is set to be the center value of the design when the volume of the mold space of the molding die and the volume of the glass preform are at the center values ​​of the upper and lower changes, respectively.

[0007] The volume absorption part is a part that allows for shape deviation, so the area of ​​the volume absorption part in the flange part cannot be used for precise positioning of the lens relative to the retaining member. When the area for positioning the lens is not sufficiently ensured in the flange part, the position accuracy and stability of the lens deteriorate. Therefore, in the flange part, in addition to having a size that can achieve high-precision positioning, it is necessary to further add the size of the volume absorption part for absorbing errors during molding, which restricts the miniaturization of the flange part.

[0008] In addition, in the glass molded lens, there is a problem that the portion with a small thickness and a sharp angle change is prone to cracking and breaking. Therefore, since it is necessary to ensure the strength of the flange part itself, the thickness reduction of the flange part is restricted.

[0009] When molding a glass molded lens, the glass preform is difficult to extend when there is a small space in the molding mold, and the temperature needs to be increased to reduce the viscosity of the glass preform. Therefore, in order to form a thin flange, the glass preform is heated to a temperature higher than the temperature required to form the lens surface, which may deteriorate the accuracy and appearance quality of the lens surface.

[0010] Based on the above reasons, there are limitations on the thinning of the flange of the glass molded lens, and it is required to solve this problem. As a technology for positioning the lens without relying on the flange, it is known that a frame member (bracket) made of other materials such as metal is set on the outer periphery of the lens, and the frame member is integrated with the frame member by press molding while molding the lens (for example, Patent Documents 1, 2, 3).

[0011] Prior art literature

[0012] Patent Literature

[0013] Patent document 1: Japanese Patent Application Publication No. 3-167514;

[0014] Patent document 2: Japanese Patent No. 3679489;

[0015] Patent Document 3: Japanese Patent Application Publication No. 2008-88027.

[0016] Problems to be solved by utility models

[0017] In the invention of Patent Document 1, a glass molded lens has a flange portion including a plane perpendicular to the optical axis on the outside of the aspherical lens surface, and a metal frame member is provided on the outside of the flange portion. Therefore, the above-mentioned problem that the flange portion is difficult to be thinned due to manufacturing constraints of the glass molded lens cannot be solved.

[0018] Furthermore, in the prior art including Patent Documents 1, 2 and 3 in which a frame member is disposed on the outer peripheral side of a glass molded lens, no specific conditions for achieving miniaturization and lightness of the lens holding portion without impairing optical performance are provided with respect to the dimensional relationship between the glass molded lens and the frame member. Utility Model Content

[0019] The present invention is completed based on the above problem awareness, and its object is to provide a lens that can ensure optical performance and reduce the size and weight of the lens holding part.

[0020] Another object of the present invention is to provide a lens molding die capable of manufacturing a lens having a lens holding portion reduced in size and weight with high precision.

[0021] Solutions for solving problems

[0022] A lens in one embodiment of the present invention is characterized in that it comprises: an optical function portion, which is a glass press-molded product, having lens surfaces on both sides in the optical axis direction, and a volume absorption portion around the lens surface that allows shape errors accompanying press molding; and a flange portion, which is combined with the optical function portion and is composed of a material different from the glass of the optical function portion, the flange portion comprising: a barrel portion, which is formed into a barrel shape centered on the optical axis and is fixed to surround the outer peripheral surface of the optical function portion; and an annular portion, whose thickness in the optical axis direction is smaller than the length of the barrel portion in the optical axis direction, and which extends from the outer peripheral surface of the barrel portion in a direction orthogonal to the optical axis, and the length L of the barrel portion in the optical axis direction and the width W of the annular portion in the direction orthogonal to the optical axis satisfy the following condition (1):

[0023] (1)W / L≥0.8.

[0024] Preferably, the length L of the cylindrical portion in the optical axis direction and the width W of the annular portion in the direction perpendicular to the optical axis satisfy the following condition (2):

[0025] (2)W / L≤10.

[0026] Preferably, the flange portion is made of metal.

[0027] Preferably, the annular portion is provided to extend from one end of the outer peripheral surface of the cylindrical portion in the optical axis direction in a direction perpendicular to the optical axis.

[0028] Preferably, the inner peripheral surface of the flange portion and the cylindrical portion is blackened.

[0029] Preferably, outer surfaces of the flange portion, the cylindrical portion, and the annular portion are entirely blackened.

[0030] A lens molding mold in one embodiment of the utility model is used to press-mold the lens, and is characterized in that the lens molding mold has an upper mold and a lower mold, and the lower mold has: an annular portion holding surface, which is located around the lens forming surface of the lens surface forming the optical functional portion, and holds the annular portion of the flange portion; and an annular blocking protrusion, which is located around the annular portion holding surface, protrudes upwards than the annular portion holding surface, and defines the outer edge position of the annular portion.

[0031] Preferably, the upper mold has: a barrel forming surface, which is located around the lens forming surface of the lens surface forming the optical functional portion, and determines the position of the outer peripheral surface of the barrel of the flange portion; and a facing surface, which is located around the barrel forming surface and faces the annular portion retaining surface and the blocking protrusion of the lower mold.

[0032] Utility Model Effect

[0033] According to the utility model, a lens is composed of an optical functional portion having a lens surface and a volume absorption portion, and a flange portion arranged on the outside of the optical functional portion, wherein the flange portion comprises: a cylindrical portion, which surrounds the outer peripheral surface of the optical functional portion and is fixed; and an annular portion, which protrudes from the outer peripheral surface of the cylindrical portion in a direction perpendicular to the optical axis, and the length of the cylindrical portion in the optical axis direction and the width of the annular portion in the direction perpendicular to the optical axis also satisfy specified conditions, thereby being able to obtain a lens that can ensure optical performance and keep the lens part small and light.

[0034] Furthermore, according to the present invention, a lens molding die capable of manufacturing the above-mentioned lens with high precision can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a cross-sectional view showing a lens molding mold for press-molding a conventional glass molded lens.

[0036] Figure 2 It is a cross-sectional view showing the process of press-molding a conventional glass molded lens.

[0037] Figure 3 It is a cross-sectional view showing the process of press-molding a conventional glass molded lens.

[0038] Figure 4 This is a cross-sectional view of a conventional glass molded lens.

[0039] Figure 5 It is a cross-sectional view showing a lens molding die for press-molding the lens according to the present embodiment.

[0040] Figure 6 It is a cross-sectional view showing the process of press-molding the lens according to the present embodiment.

[0041] Figure 7 It is a cross-sectional view showing the process of press-molding the lens according to the present embodiment.

[0042] Figure 8 It is a cross-sectional view of the lens according to this embodiment.

[0043] Fig. 9 This is a front view of the lens of this embodiment.

[0044] Fig.10 It is a cross-sectional view of a lens unit in which the lens of this embodiment is mounted on a lens barrel.

[0045] Fig.11 It is a cross-sectional view of a lens unit in which the lens of this embodiment is mounted on a lens barrel.

[0046] Fig.12 This is a cross-sectional view showing a lens in which the inner peripheral surface of the cylindrical portion of the flange portion is blackened.

[0047] Fig.13 This is a cross-sectional view of a lens in which the outer surface of the flange portion is entirely blackened. DETAILED DESCRIPTION

[0048] First, refer to Figures 1 to 4 , the existing glass molded lens and its production are described. Figures 1 to 3 The structure and operation of the lens molding mold 10 are shown. Figure 4 The glass molded lens 20 formed by the lens molding die 10 is shown.

[0049] The lens molding mold 10 is composed of a cylindrical mold 11, a lower mold 12, and an upper mold 13. The cylindrical mold 11 is cylindrical and has an internal space surrounded by an inner peripheral surface 11a as a cylindrical surface. The central axis X1 of the lens molding mold 10 is an axis extending in the vertical direction through the center of the inner peripheral surface 11a. The lower end surface 11b and the upper end surface 11c of the cylindrical mold 11 are respectively surfaces perpendicular to the central axis X1. The internal space of the cylindrical mold 11 is through in the vertical direction and is open at the lower end surface 11b and the upper end surface 11c.

[0050] The lower mold 12 has an insertion portion 12a inserted into the internal space of the cylindrical mold 11 from below, and a large diameter portion 12b provided at the lower portion of the insertion portion 12a and having a larger diameter than the insertion portion 12a. The upper mold 13 has an insertion portion 13a inserted into the internal space of the cylindrical mold 11 from above, and a large diameter portion 13b provided at the upper portion of the insertion portion 13a and having a larger diameter than the insertion portion 13a. The outer peripheral surfaces of the insertion portion 12a and the insertion portion 13a are respectively able to slide in the up-and-down directions relative to the inner peripheral surface 11a of the cylindrical mold 11, and the movement is restricted in the direction perpendicular to the center axis X1. That is, when the lower mold 12 and the upper mold 13 are aligned so that the centers coincide with the center axis X1, the lower mold 12 and the upper mold 13 are able to move in the up-and-down directions relative to the cylindrical mold 11.

[0051] The lower mold 12 has a pressing surface 14 at the upper end of the insertion portion 12a. The pressing surface 14 has a concave lens forming surface 14a and a flange forming surface 14b located around the lens forming surface 14a. The upper mold 13 has a pressing surface 15 at the lower end of the insertion portion 13a. The pressing surface 15 has a concave lens forming surface 15a and a flange forming surface 15b located around the lens forming surface 15a.

[0052] The lower mold 12 can be inserted into the cylindrical mold 11 until the large diameter portion 12b abuts against the lower end surface 11b. The upper mold 13 can be inserted into the cylindrical mold 11 until the large diameter portion 13b abuts against the upper end surface 11c. The position where the lower mold 12 and the upper mold 13 are inserted to the deepest relative to the cylindrical mold 11 is called the pressing moving end. Figure 1 As shown, when the lower mold 12 and the upper mold 13 reach their respective pressing moving ends, the pressing surfaces 14 and 15 face each other with a specified interval in the up and down directions, forming a mold space S1 surrounded by the pressing surfaces 14 and 15 and the inner peripheral surface 11a.

[0053] When the glass molded lens 20 is molded using the lens molding mold 10, as shown in FIG. Figure 2As shown in FIG. 1 , a spherical glass preform PF1 made of glass, which is the base material of the glass molded lens 20, is placed on the pressing surface 14 of the lower mold 12. The glass preform PF1 is maintained at a position on the central axis X1 by the concave shape of the lens forming surface 14a. The lower mold 12 is maintained at the pressing moving end so that the large diameter portion 12b abuts against the lower end surface 11b, and the lower mold 12 is supported from below in a manner that the insertion portion 12a does not detach from the cylindrical mold 11. In addition, the supply of the glass preform PF1 to the pressing surface 14 can be performed in a state where the insertion portion 12a is pulled downward from the cylindrical mold 11, or it can be performed from the upper end side of the cylindrical mold 11 in a state where the insertion portion 12a is inserted into the cylindrical mold 11.

[0054] The glass preform PF1 is heated to a temperature higher than the glass transition temperature to be softened, and the upper mold 13 is pressed downward with the insertion portion 13a inserted into the cylindrical mold 11. The glass preform PF1 is pressed between the pressing surface 15 of the descending upper mold 13 and the pressing surface 14 of the lower mold 12 whose descent is restricted, and the glass preform PF1 is deformed.

[0055] When the upper die 13 descends to Figure 3 When the pressing is moved to the end shown, the glass preform PF1 becomes a shape corresponding to the mold space S1. Then, by disassembling the lens molding mold 10 after cooling to a predetermined temperature, the molded glass molded lens 20 can be taken out. The glass molded lens 20 is a lens to which the surface shapes of the pressing surface 14, the pressing surface 15 and the inner peripheral surface 11a are transferred.

[0056] The direction along the optical axis Xa of the glass molded lens 20 is referred to as the optical axis direction, and the direction perpendicular to the optical axis Xa is referred to as the optical axis orthogonal direction. The optical axis orthogonal direction can also be referred to as the radial direction of the glass molded lens 20.

[0057] like Figure 4 As shown, the glass molded lens 20 has a convex lens surface 21 to which the surface shape of the lens forming surface 14a is transferred, and a convex lens surface 22 to which the surface shape of the lens forming surface 15a is transferred, on both sides (front and back) in the optical axis direction. The glass molded lens 20 also has an annular flange portion 23 around the lens surface 21 and the lens surface 22. The flange portion 23 is a portion surrounded by a first plane 23a to which the surface shape of the flange forming surface 14b is transferred, a second plane 23b to which the surface shape of the flange forming surface 15b is transferred, and an outer peripheral surface 23c to which the surface shape of the inner peripheral surface 11a of the cylindrical mold 11 is transferred. The first plane 23a and the second plane 23b are planes perpendicular to the optical axis Xa, and the outer peripheral surface 23c is a cylindrical surface centered on the optical axis Xa.

[0058] When the glass molded lens 20 is manufactured using the lens molding mold 10, various errors may occur, such as the capacity error of the glass preform PF1, the volume error of the mold space S1 of the lens molding mold 10, and the deviation of the supply position of the glass preform PF1. The glass molded lens 20 has a volume absorbing portion 24 and a volume absorbing portion 25 at the outer peripheral corner of the flange portion 23 for absorbing the influence of these errors.

[0059] Specifically, the volume absorption portion 24 connects the first plane 23a and the outer peripheral surface 23c in a rounded shape (R-angle shape), that is, the rounded shape is located at the inner side of the angle shape when the first plane 23a and the outer peripheral surface 23c are extended according to their shapes and intersect. The volume absorption portion 25 connects the second plane 23b and the outer peripheral surface 23c in a rounded shape (R-angle shape), that is, the rounded shape is located at the inner side of the angle shape when the second plane 23b and the outer peripheral surface 23c are extended according to their shapes and intersect. The volume absorption portion 24 and the volume absorption portion 25 are portions that allow shape deviations corresponding to the various errors mentioned above. Therefore, Figure 4 The shapes of the volume absorbing parts 24 and 25 shown are examples, and the shapes of the volume absorbing parts 24 and 25 differ depending on the degree of error. In addition, by having the volume absorbing parts 24 and 25, other parts of the glass molded lens 20 can be formed with high precision.

[0060] On the other hand, the glass molded lens 20 cannot be positioned relative to the lens barrel of the lens unit at the volume absorbing portion 24 and the volume absorbing portion 25. Therefore, by providing the volume absorbing portion 24 and the volume absorbing portion 25 in the flange portion 23, the size of the surface of the flange portion 23 that serves as the reference for positioning the glass molded lens 20 becomes relatively smaller. For example, when the width of the flange portion 23 in the direction perpendicular to the optical axis is fixed, the larger the formation range of the volume absorbing portion 24 and the volume absorbing portion 25 in the direction perpendicular to the optical axis, the smaller the width of the first plane 23a and the second plane 23b in the direction perpendicular to the optical axis. When the first plane 23a and the second plane 23b are used to position the glass molded lens 20 in the direction perpendicular to the optical axis, when the width of the first plane 23a and the second plane 23b in the direction perpendicular to the optical axis becomes smaller, there is a risk that the positioning accuracy and the stability of holding will deteriorate when the glass molded lens 20 is mounted on the lens barrel of the lens unit. Furthermore, when the thickness of the flange 23 in the optical axis direction is constant, the larger the range of the volume absorbing portions 24 and 25 in the optical axis direction is, the smaller the optical axis direction length of the outer peripheral surface 23c in the flange 23 is. When the outer peripheral surface 23c is used to position the glass molded lens 20 in the direction orthogonal to the optical axis, if the optical axis direction length of the outer peripheral surface 23c becomes smaller, there is a risk that the positioning accuracy and the stability of holding will deteriorate when the glass molded lens 20 is mounted on the lens barrel of the lens unit.

[0061] Therefore, in addition to having a sufficient size for obtaining the positioning function, the flange portion 23 also needs to have a size for obtaining the error absorption function of the volume absorption portion 24 and the volume absorption portion 25, which restricts the miniaturization of the flange portion 23. In other words, concentrating the positioning function of the glass molded lens 20 and the error absorption function during molding on the flange portion 23 is one of the main reasons for restricting the miniaturization of the flange portion 23.

[0062] In addition, in general, in a glass molded lens, cracks and breakages are more likely to occur in the portion where the thickness is small and the angle changes sharply. Figure 4 In the case of the glass molded lens 20 shown, the boundary between the convex lens surface 21 and the first plane 23a, and the boundary between the convex lens surface 22 and the second plane 23b are portions that are particularly prone to cracking and breakage. Therefore, even if the flange 23 is thinned in the optical axis direction without considering the restrictions of the above-mentioned volume absorption parts 24 and 25, there is still a problem that the smaller the thickness of the flange 23, the higher the risk of cracking and breakage. Therefore, in the glass molded lens 20, from the perspective of ensuring the strength of the flange 23 itself, the miniaturization of the flange 23 (especially the thinning in the optical axis direction) is also restricted.

[0063] In addition, when molding a glass molded lens, attention must be paid to the fluidity of the glass preform within the space of the lens molding mold. Figure 1 In the mold space S1 of the lens molding mold 10 shown, the space in the center portion between the lens forming surface 14a and the lens forming surface 15a is large, and the space in the peripheral portion between the flange forming surface 14b and the flange forming surface 15b is small.

[0064] In order to make the glass preform PF1 extend in the narrow space at the periphery of the mold space S1 during pressing, the glass preform PF1 needs to be made low in viscosity. That is, in order to form a flange portion 23 thinner in the optical axis direction than the effective diameter portion (the range of the lens surface 21 and the lens surface 22) in the glass molded lens 20, the glass preform PF1 with low viscosity needs to be extended in the narrow space at the periphery of the mold space S1. Moreover, in order to make the forming portion of the flange portion 23 low in viscosity, it is necessary to increase the temperature of the glass preform PF1 to a temperature (for example, a second temperature) higher than the temperature (for example, a first temperature) required to extend the forming portion of the lens surface 21 and the lens surface 22. When the lens surface 21 and the lens surface 22 that can be formed at the first temperature are formed at a second temperature higher than the first temperature, the influence of heat shrinkage after molding becomes greater, and the accuracy and appearance quality of the lens surfaces 21 and 22 may be deteriorated compared to the case where they are formed at the first temperature.

[0065] As the flange 23 is thinner in the optical axis direction, the space for forming the flange 23 in the mold space S1 becomes smaller, and the glass preform PF1 becomes more difficult to extend. Therefore, during molding, the glass preform PF1 needs to be further reduced in viscosity (i.e., heated to a high temperature). As a result, as the flange 23 is thinner in the optical axis direction, it becomes more difficult to ensure the accuracy and appearance quality of the lens surfaces 21 and 22. In other words, from the perspective of ensuring the quality of the effective diameter portion of the glass molded lens 20 including the lens surfaces 21 and 22, the miniaturization of the flange 23 (especially the thinning in the optical axis direction) is also restricted.

[0066] In addition, as a countermeasure for the case where the glass preform PF1 is stretched at the thin and easily cracked flange portion 23, it is known to provide a mold release film to suppress cracking or to perform a surface treatment on the glass preform PF1 to make it less likely to crack. However, when a mold release film or surface treatment is performed to avoid such cracking, turbidity is easily generated on the outer surface of the glass mold-cast lens 20, and there is a problem that the surface accuracy of the outer surface of the glass mold-cast lens 20 is unstable.

[0067] When the glass molded lens 20 is molded by the lens molding mold 10, when the upper mold 13 is lowered and the glass preform PF1 is pressurized, the outer periphery of the glass preform PF1 may be bent upward due to the pressure applied to the glass preform PF1 from the lens forming surface 15a of the upper mold 13, and the outer periphery of the glass preform PF1 may contact the lens forming surface 15a before the inner periphery thereof. Alternatively, the outer periphery of the glass preform PF1 may be bent downward, and the outer periphery of the glass preform PF1 may contact the lens forming surface 14a before the inner periphery thereof. In this case, gas is sealed between the glass preform PF1 and the lens forming surface 15a, and between the glass preform PF1 and the lens forming surface 14a, and so-called bubbles are generated. Bubbles may cause the shape of the glass molded lens 20 to be defective.

[0068] In order to avoid bubbles, it is necessary to make the curvature radius of the glass preform PF1 smaller than the curvature radius of the lens forming surface 14a and the lens forming surface 15a of the lens molding mold 10 by a predetermined amount or more. However, in order to form a glass molded lens 20 of a corresponding volume including the flange portion 23, the volume of the glass preform PF1 required becomes large, and it is difficult to set the curvature radius of the glass preform PF1 small. In addition, due to the various reasons mentioned above, there is a limit to the miniaturization of the flange portion 23, and there is also a limit to the countermeasure of reducing the amount of the glass preform PF1 to avoid bubbles.

[0069] and Figure 4 Different from the glass molded lens 20 shown in the figure, there is a known glass molded lens in which a plurality of stepped shapes are provided on the flange portion to divide the positioning function portion and the volume absorption portion. In addition, there is a known glass molded lens in which a volume absorption portion is provided in a shape protruding from the positioning function portion of the flange portion in the optical axis direction. In each of these glass molded lenses, the volume absorption portion or the positioning function portion becomes a flange portion of a curved and complex shape, which is disadvantageous in strength and it is difficult to mold the positioning function portion with high precision.

[0070] In view of the various problems of the existing glass molded lenses as mentioned above, the present invention provides a lens that can ensure optical performance and keep the lens retaining part small and lightweight. In addition, a lens molding mold that can manufacture such a lens with high precision is provided. The present invention focuses on forming a lens with an optical function part and a flange part, wherein the optical function part is composed of a pressed glass product and includes a lens surface, and the flange part is composed of a material different from the glass of the optical function part and is arranged on the outside of the optical function part, and the optical function part has a necessary minimum structure for realizing the optical function and the error absorption function during molding, so that the flange part assumes the positioning function of the lens, thereby being able to solve the above-mentioned problems.

[0071] Next, refer to Figures 5 to 9, a lens and its manufacturing method to which an embodiment of the present utility model is applied are described. Figures 5 to 7 The structure and operation of the lens molding mold 30 are shown. Figure 8 and Fig. 9 The lens 40 of this embodiment is formed by the lens molding die 30. The direction along the optical axis Xb of the lens 40 is the optical axis direction, and the direction perpendicular to the optical axis Xb is the optical axis orthogonal direction.

[0072] The lens molding mold 30 is composed of a cylindrical mold 31, a lower mold 32, and an upper mold 33. The cylindrical mold 31 is cylindrical in shape and has an internal space surrounded by an inner peripheral surface 31a which is a cylindrical surface. The central axis X2 of the lens molding mold 30 is an axis extending in the up-down direction through the center of the inner peripheral surface 31a. The cylindrical mold 31 has a cylindrical mold lower end surface 31b at the lower end and a cylindrical mold upper end surface 31c at the upper end. The cylindrical mold lower end surface 31b and the cylindrical mold upper end surface 31c are respectively surfaces perpendicular to the central axis X2. The internal space of the cylindrical mold 31 is through in the up-down direction and is open at the cylindrical mold lower end surface 31b and the cylindrical mold upper end surface 31c.

[0073] The lower mold 32 has an insertion portion 32a inserted into the internal space of the cylindrical mold 31 from below and a large diameter portion 32b provided at the lower portion of the insertion portion 32a and having a larger diameter than the insertion portion 32a. The upper mold 33 has an insertion portion 33a inserted into the internal space of the cylindrical mold 31 from above and a large diameter portion 33b provided at the upper portion of the insertion portion 33a and having a larger diameter than the insertion portion 33a. The outer peripheral surfaces of the insertion portion 32a and the insertion portion 33a can slide in the up-down direction relative to the inner peripheral surface 31a of the cylindrical mold 31, and are restricted from moving in the direction perpendicular to the center axis X2. That is, in a state where the centers of the lower mold 32 and the upper mold 33 are aligned to coincide with the center axis X2, the lower mold 32 and the upper mold 33 can move in the up-down direction relative to the cylindrical mold 31.

[0074] The lower mold 32 has a lens forming surface 34, an annular portion holding surface 35, and a blocking convex portion 36 at the upper end of the insertion portion 32a. The lens forming surface 34 is a surface that participates in the formation of the optical functional portion 41 described later, and the annular portion holding surface 35 and the blocking convex portion 36 are surfaces that participate in the formation of the flange portion 42 described later. The lens forming surface 34 is a concave surface that is deepest at the center on the central axis X2 and becomes shallower toward the outer peripheral side. The annular portion holding surface 35 is a surface perpendicular to the central axis X2, and is an upward annular surface arranged around the lens forming surface 34 in an annular range centered on the central axis X2. The blocking convex portion 36 is an annular protrusion formed around the annular portion holding surface 35 and protruding upward relative to the lens forming surface 34 and the annular portion holding surface 35. The upper surface of the blocking convex portion 36 is an annular surface perpendicular to the central axis X2. The inner peripheral surface of the blocking protrusion 36 is a cylindrical surface centered on the central axis X2.

[0075] The upper mold 33 has a lens forming surface 37, a barrel forming surface 38, and a facing surface 39 at the lower end of the insertion portion 33a. The lens forming surface 37 is a surface that participates in forming the optical function portion 41 described later, and the barrel forming surface 38 and the facing surface 39 are surfaces that participate in forming the flange portion 42 described later. The lens forming surface 37 is a concave surface that is deepest at the center on the central axis X2 and becomes shallower toward the outer peripheral side. The barrel forming surface 38 is a cylindrical surface that protrudes downward from the outer edge of the lens forming surface 37, and is formed as the inner peripheral surface of a cylinder centered on the central axis X2. The facing surface 39 is a surface perpendicular to the central axis X2, and is set around the barrel forming surface 38 in an annular range centered on the central axis X2. In other words, the barrel forming surface 38 and the facing surface 39 constitute an annular protrusion that protrudes downward around the lens forming surface 37.

[0076] When the lens 40 is formed by press molding, the position where the insertion portion 32a of the lower mold 32 and the insertion portion 33a of the upper mold 33 are inserted deepest relative to the cylindrical mold 31 is called the press moving end of the lower mold 32 and the upper mold 33. Figure 5 As shown, when the lower mold 32 and the upper mold 33 reach their respective pressing moving ends, the lens forming surface 34 and the lens forming surface 37 face each other with a predetermined interval in the vertical direction, and a mold space S2 is formed between the lower mold 32 and the upper mold 33. The mold space S2 is a space surrounded by the lens forming surface 34, the annular portion holding surface 35 and the blocking convex portion 36 of the lower mold 32, and the lens forming surface 37, the barrel forming surface 38 and the facing surface 39 of the upper mold 33. The facing surface 39 faces both the annular portion holding surface 35 and the upper surface of the blocking convex portion 36.

[0077] As an example, the position where the large diameter portion 32b contacts the lower end surface 31b of the cylindrical mold is set as the pressing moving end of the lower mold 32. In addition, the position where the large diameter portion 33b contacts the upper end surface 31c of the cylindrical mold is set as the pressing moving end of the upper mold 33. Alternatively, in the upper mold 33, the pressing moving end may be determined by a structure other than the contact between the large diameter portion 33b and the upper end surface 31c of the cylindrical mold.

[0078] like Figure 8 and Fig. 9 As shown, the lens 40 is composed of a glass optical function portion 41 and a flange portion 42 surrounding the outer side of the optical function portion 41. The flange portion 42 is composed of a material different from the glass of the optical function portion 41. In this embodiment, the flange portion 42 is made of metal. The softening temperature of the metal constituting the flange portion 42 is equal to or higher than the glass transition temperature of the glass constituting the optical function portion 41. As an example, the flange portion 42 is formed of copper.

[0079] Before using the lens molding mold 30 to press-form the optical function part 41, a flange part 42 is prepared in advance, which has a cylindrical barrel part 42a centered on the optical axis Xb of the lens 40 and a ring-shaped annular part 42b extending from the outer peripheral surface of the barrel part 42a in the direction perpendicular to the optical axis. Let the length of the barrel part 42a in the optical axis direction be L, and let the thickness of the barrel part 42a in the direction perpendicular to the optical axis be t1. Let the width of the annular part 42b in the direction perpendicular to the optical axis be W, and let the thickness of the annular part 42b in the direction perpendicular to the optical axis be t2. The thickness t1 of the barrel part 42a in the direction perpendicular to the optical axis is smaller than the width W of the annular part 42b in the direction perpendicular to the optical axis. The thickness t2 of the annular part 42b in the direction perpendicular to the optical axis is smaller than the length L of the barrel part 42a in the direction perpendicular to the optical axis. The annular portion 42b extends from one end of the outer peripheral surface of the cylindrical portion 42a in the optical axis direction in a direction perpendicular to the optical axis. When the flange portion 42 is observed in a cross-sectional view along the optical axis Xb, it appears as follows: Figure 8 L-shape as shown.

[0080] When the lens 40 is formed using the lens forming mold 30, as shown in FIG. Figure 6 As shown in FIG. 1 , the flange portion 42 formed into an L-shaped cross-sectional shape is preliminarily installed inside the lens molding mold 30. The flange portion 42 is held in the lower mold 32 in a state where the lower surface of the annular portion 42b is placed on the annular portion holding surface 35 and the outer edge of the annular portion 42b faces the inner peripheral surface of the blocking protrusion 36. The annular portion 42b is held by the annular portion holding surface 35, thereby defining the position of the flange portion 42 in the direction along the central axis X2. In addition, the flange portion 42 is held in a manner of being embedded in the inner side of the blocking protrusion 36, so that the installation position of the flange portion 42 in the direction perpendicular to the central axis X2 can be easily defined. In the state where the flange portion 42 is held in the lower mold 32, the cylinder portion 42a protrudes upward from the outer edge of the lens forming surface 34, and the top end of the cylinder portion 42a is located above the upper surface of the blocking protrusion 36. In addition, the upper surface of the annular portion 42b is in a substantially flush relationship with the upper surface of the blocking protrusion 36. In addition, the upper surface of the annular portion 42 b may protrude slightly upward from the upper surface of the blocking protrusion 36 .

[0081] like Figure 6As shown, the flange portion 42 is provided inside the lens molding mold 30, and a spherical glass preform PF2 made of glass as a base material of the optical functional portion 41 is placed on the lens forming surface 34 of the lower mold 32. The glass preform PF2 is maintained in a position on the central axis X2 by the concave shape of the lens forming surface 34. The lower mold 32 is maintained at a pressing moving end so that the large diameter portion 32b abuts against the lower end surface 31b of the cylindrical mold, and the lower mold 32 is supported from below so that the insertion portion 32a does not detach from the cylindrical mold 31. In addition, the glass preform PF2 can be supplied to the lens forming surface 34 in a state where the insertion portion 32a is pulled downward from the cylindrical mold 31, or it can be supplied from the upper end side of the cylindrical mold 31 in a state where the insertion portion 32a is inserted into the cylindrical mold 31. In addition, in Figure 6 In the embodiment, the glass preform PF2 is spherical, but a glass preform having a shape other than a sphere may be used.

[0082] The glass preform PF2 is heated to a temperature higher than the glass transition temperature to be softened, and the upper mold 33 is pressed downward with the insertion portion 33a inserted into the cylindrical mold 31. The glass preform PF2 is pressed between the lens forming surface 37 of the descending upper mold 33 and the lens forming surface 34 of the lower mold 32 whose descent is restricted, and the glass preform PF2 is deformed.

[0083] When the upper die 33 is lowered to Figure 7 When the pressing movement end is shown, the glass preform PF2 becomes an optical functional part 41 having a shape corresponding to the mold space S2. In more detail, since the flange part 42 is arranged at the peripheral portion of the mold space S2, the optical functional part 41 is pressed and formed in the inner area of ​​the flange part 42 in the mold space S2, and the outer peripheral part of the optical functional part 41 is closely fixed to the inner peripheral surface of the cylinder part 42a, and the optical functional part 41 and the flange part 42 are combined.

[0084] Furthermore, when the upper mold 33 is lowered, the barrel forming surface 38 of the upper mold 33 contacts the outer peripheral surface of the barrel 42a of the flange 42, and the facing surface 39 contacts the upper surface of the annular portion 42b of the flange 42. When the upper mold 33 is moved to the pressing moving end, the pressing force acts on the flange 42 from the upper mold 33, and the flange 42 is slightly plastically deformed. In detail, the position of the outer peripheral surface of the barrel 42a is specified by the barrel forming surface 38 of the upper mold 33, and the shape of the barrel 42a is adjusted. The annular portion 42b is sandwiched between the annular portion holding surface 35 of the lower mold 32 and the facing surface 39 of the upper mold 33, forming the front and back surfaces in the optical axis direction, and the outer edge position is specified by the inner peripheral surface of the stopper convex portion 36. In this way, in the mold space S2, in addition to the optical function portion 41, the flange 42 is also press-molded and processed into a final shape.

[0085] The optical function portion 41 and the flange portion 42 are press-molded as described above, and the lens molding die 30 is disassembled after being cooled to a predetermined temperature, so that the molded lens 40 can be taken out.

[0086] The flange portion 42 may be formed of a metal having a greater thermal expansion coefficient than the material constituting the lens molding mold 30, and in a state before heating to soften the glass preform PF2, a small gap may exist between the outer edge of the annular portion 42b of the flange portion 42 and the inner side of the blocking protrusion 36 of the lower mold 32. In this case, the flange portion 42 is expanded by heating, and the flange portion 42 and the lens molding mold 30 are closely fitted by utilizing the difference in thermal expansion coefficient. Specifically, the outer edge of the annular portion 42b of the flange portion 42 is closely fitted to the inner peripheral surface of the blocking protrusion 36 by the expansion of the flange portion 42. By constructing the lens molding mold 30 in advance in such a way that the center axis X2 of the lens molding mold 30 is matched with the optical axis Xb of the molded lens 40 with high precision, the flange portion 42 expanded due to heating is isotropically fitted with the inner circumferential surface of the blocking protrusion 36, thereby improving the eccentricity accuracy relative to the lens molding mold 30, and obtaining a lens 40 in which the center position of the flange portion 42 is coaxial with the optical functional portion 41 with high precision.

[0087] As described above, the hybrid structure lens 40 is formed by the optical function portion 41 which is a glass press-molded product and the flange portion 42 made of metal. Figure 8 As shown, the optical function portion 41 of the lens 40 has a convex lens surface 43 on both sides (front and back) of the optical axis direction, which has the surface shape of the lens forming surface 34 transferred, and a convex lens surface 44 on which the surface shape of the lens forming surface 37 is transferred. The lens surface 43 and the lens surface 44 of the lens 40 of this embodiment are both aspherical aspherical lenses. In addition, the lens of the utility model is not limited to aspherical lenses, and can also be applied to spherical lenses.

[0088] The outer peripheral portion of the optical function part 41 becomes an outer peripheral surface 45 that is closely fixed to the inner peripheral surface of the barrel 42a of the flange part 42. The outer peripheral surface 45 becomes a cylindrical surface centered on the optical axis Xb by following the inner peripheral surface of the barrel 42a. The length L of the barrel 42a in the optical axis direction covers the entire length of the outer peripheral surface 45 of the optical function part 41 in the optical axis direction, and when the optical function part 41 is molded, the glass is prevented from flowing out of the barrel 42a to the outside (the annular portion 42b side of the flange part 42) in the direction orthogonal to the optical axis. Therefore, the shape of the outer peripheral surface 45 of the optical function part 41 is managed with high precision by the barrel 42a.

[0089] The outer corners of the optical function portion 41 are provided with volume absorption portions 46 and 47 for absorbing the influence of errors during molding caused by the lens molding mold 30. Errors during molding refer to volume errors of the glass preform PF2, volume errors of the mold space S2 of the lens molding mold 30, deviations in the supply position of the glass preform PF2 to the lens molding mold 30, and the like.

[0090] The volume absorption portion 46 connects the boundary portion of the lens surface 43 and the outer peripheral surface 45 in a rounded shape (R-angle shape), that is, the inner position of the angle shape when the lens surface 43 is extended according to the designed lens surface shape and intersects with the outer peripheral surface 45. The volume absorption portion 47 connects the boundary portion of the lens surface 44 and the outer peripheral surface 45 in a rounded shape (R-angle shape), that is, the inner position of the angle shape when the lens surface 44 is extended according to the designed lens surface shape and intersects with the outer peripheral surface 45. The volume absorption portion 46 and the volume absorption portion 47 are portions that allow shape deviations corresponding to the various errors mentioned above. Therefore, Figure 8 The shapes of volume absorbing portions 46 and 47 shown are just examples, and the shapes of volume absorbing portions 46 and 47 may be different depending on the degree of error.

[0091] By having the volume absorbing parts 46 and 47, it is possible to prevent errors during press molding from affecting other parts of the optical functional part 41, and it is possible to form the lens surface 43 and the lens surface 44 with high precision. In addition, the volume absorbing parts 46 and 47 are not shapes that protrude or recess sharply from the optical functional part 41, but are shapes that smoothly connect the lens surfaces 43, 44 and the peripheral surface 45, so it is not easy to cause the optical functional part 41 to be cracked or damaged by the volume absorbing parts 46 and 47.

[0092] In this way, the volume absorbing portion 46 and the volume absorbing portion 47 can absorb the error accompanying the press molding of the optical function portion 41. In addition, it is not the optical function portion 41 but the flange portion 42 that has the position reference surface for positioning the lens 40. In other words, the functions of the lens 40 are divided as follows: the flange portion 42 has a positioning function, and the optical function portion 41 has an error absorbing function during press molding.

[0093] Fig.104 shows a lens unit 50 in which a lens 40 is assembled in a lens barrel 51. The lens unit 50 has a cylindrical lens barrel 51, and a lens barrel inner space 52 is formed inside the lens barrel 51 and penetrates in the optical axis direction. In the lens barrel inner space 52, there are formed: a stopper surface 53 extending in a direction perpendicular to the optical axis; a large-diameter cylindrical surface 54 extending from the outer edge of the stopper surface 53 in the optical axis direction; and a small-diameter cylindrical surface 55 extending from the inner edge of the stopper surface 53 in the optical axis direction. The inner diameter of the large-diameter cylindrical surface 54 is larger than the outer diameter of the annular portion 42b of the flange portion 42 (i.e., the diameter of the lens 40).

[0094] With the lens surface 44 facing forward in the insertion direction, the lens 40 is inserted into the interior of the lens barrel 51 from the open end of the large-diameter cylindrical surface 54 (the end on the opposite side of the stop surface 53). When the annular portion 42b of the flange portion 42 abuts against the stop surface 53, the insertion of the lens 40 in the optical axis direction is restricted, and the position of the lens 40 in the optical axis direction is specified. In other words, the annular portion 42b constitutes a position reference surface for specifying the position of the lens 40 in the optical axis direction. By specifying the position in the optical axis direction via the annular portion 42b extending in the direction orthogonal to the optical axis, high-precision positioning with excellent stability can be achieved.

[0095] The position of the lens 40 relative to the lens barrel 51 in the direction perpendicular to the optical axis can be determined by the contact between the outer peripheral surface of the cylindrical portion 42a of the flange portion 42 and the small diameter cylindrical surface 55 of the lens barrel 51. By determining the position in the direction perpendicular to the optical axis via the cylindrical portion 42a extending in the optical axis direction, high-precision positioning with excellent stability can be achieved.

[0096] As another aspect, the position of the lens 40 relative to the lens barrel 51 in the direction perpendicular to the optical axis can be defined by the contact between the outer edge of the annular portion 42 b of the flange 42 and the large-diameter cylindrical surface 54 of the lens barrel 51 .

[0097] As another method, the following core adjustment structure may be provided: a gap capable of adjusting the position in the direction orthogonal to the optical axis is provided between the small-diameter cylindrical surface 55, the large-diameter cylindrical surface 54 and the outer peripheral portion of the flange portion 42; on this basis, when the lens 40 is fixed relative to the lens barrel 51, the position of the lens 40 in the direction orthogonal to the optical axis is specified.

[0098] The lens 40 whose position is defined in this way is fixed inside the lens barrel 51. The lens 40 can be fixed to the lens barrel 51 in various ways. For example, the flange 42 can be bonded to the stopper surface 53.

[0099] like Fig.11As shown, a screw hole 56 is formed on the limiting surface 53 of the lens barrel 51, and a through hole 57 penetrating in the optical axis direction is formed in the annular portion 42b of the flange portion 42, so that a fixing screw 58 passes through the through hole 57 of the annular portion 42b and is screwed into the screw hole 56 on the limiting surface 53, thereby fixing (screw fixing) the lens 40 to the lens barrel 51.

[0100] Alternatively, after the lens 40 is inserted into the lens barrel 51 , another fixing member is inserted into the inner space 52 of the lens barrel, and the annular portion 42 b of the flange 42 is clamped between the stopper surface 53 and the fixing member, thereby fixing the lens 40 .

[0101] exist Fig.10 and Fig.11 In the lens unit 50, an example is shown in which only the lens 40 is arranged in the lens barrel 51, but the optical system of the lens unit 50 can also be composed of a plurality of lenses. In this case, after the lens 40, the optical axis direction of another lens inserted into the lens barrel 51 can be positioned with the annular portion 42b of the flange portion 42 as a reference (contacting the annular portion 42b of the flange portion 42).

[0102] Figure 4 The flange portion 23 of the glass molded lens 20 of the comparative example shown has the following structure, with the thickness of the outermost periphery of the optically effective diameter (the outer edge portion of the lens surfaces 21 and 22) as a reference, and the thickness is maintained to extend in the direction orthogonal to the optical axis. In the glass molded lens 20, which is entirely formed of glass including the flange portion 23, when the shape is suddenly changed from the lens surfaces 21 and 22 to the flange portion 23, cracks and breakages are easily generated. In this way, there is a restriction that the entire flange portion 23 is formed based on the shape of the outermost periphery of the optically effective diameter. Furthermore, in the flange portion 23, the corresponding thickness of the volume absorption portion 24 and the volume absorption portion 25 are required on both sides of the outer peripheral surface 23c in the optical axis direction. Therefore, in the glass molded lens 20, it is difficult to reduce the thickness of the flange portion 23 in the optical axis direction. Furthermore, if the thickness of the flange 23 in the optical axis direction changes sharply in the middle of the direction perpendicular to the optical axis, the flange 23 formed of glass is easily cracked or damaged, so the thickness of the flange 23 in the optical axis direction must be uniform over the entirety. Therefore, it is difficult to achieve lightweighting by partially reducing the thickness of the flange 23 of the glass molded lens 20 or partially reducing the weight.

[0103] In order to obtain the desired optical performance, the lens 40 of this embodiment needs to have a predetermined thickness in the optical axis direction of the outermost periphery (the outer edge of the lens surfaces 43 and 44) ​​of the optical effective diameter of the optical functional portion 41. In other words, the minimum thickness in the optical axis direction of the outer peripheral surface 45 of the optical functional portion 41 is restricted by the optical performance of the lens 40. However, only a part of the optical functional portion 41 is formed of glass, and the flange portion 42 on the outside of the optical functional portion 41 can be formed of a metal of a material different from that of the optical functional portion 41. Therefore, there is no need to consider the risk of cracking or damage of the optical functional portion 41, and the flange portion 42 can be formed with a higher degree of freedom in shape.

[0104] For example, the flange portion 42 of the lens 40 does not need a shape for absorbing errors during lens molding, such as the volume absorbing portion 46 and the volume absorbing portion 47, and the flange portion 42 can be easily thinned in the optical axis direction.

[0105] Furthermore, the flange portion 42 of the lens 40 is composed of a barrel portion 42a extending in the optical axis direction along the outer peripheral surface 45 of the optical functional portion 41 and an annular portion 42b extending in the optical axis orthogonal direction from the outer peripheral surface of the barrel portion 42a. The thickness t1 of the barrel portion 42a in the optical axis orthogonal direction is smaller than the overall size of the flange portion 42 in the optical axis orthogonal direction (the width W of the annular portion 42b from the outer peripheral surface 45 of the optical functional portion 41 to the outer edge of the annular portion 42b). In addition, the thickness t2 of the annular portion 42b in the optical axis direction is smaller than the overall size of the flange portion 42 in the optical axis direction (the length L of the barrel portion 42a in the optical axis direction). In other words, the flange portion 42 is composed of a thin barrel portion 42a in the optical axis orthogonal direction and a thin annular portion 42b in the optical axis direction. Therefore, compared to a structure in which a flange portion having the same thickness as the outer peripheral surface 45 of the optical functional portion 41 in the optical axis direction is protruded in a direction orthogonal to the optical axis (such as a structure such as the flange portion 23 of the glass molded lens 20), the flange portion 42 having an L-shaped cross-section structure formed by the cylindrical portion 42a and the annular portion 42b is constructed to be more compact and lightweight.

[0106] By Figure 8 The flange portion 42 of the lens 40 of the present embodiment shown in the figure is Figure 4 By comparing the flange 23 of the glass molded lens 20 shown in FIG. 1 , it can be seen that the flange 42 of the present embodiment is a weight-reducing structure in which only a part (two sides) of the flange 23 having a rectangular cross section remains, and can achieve significant weight reduction compared to the flange 23. For example, when the optical function portion 41 of the lens 40 is formed of the same glass material as the glass molded lens 20, the lens 40 can achieve a weight reduction of about 5 to 10% compared to the glass molded lens 20.

[0107] On the other hand, Fig.10 and Fig.11As shown, the portion of the flange 42 of the lens 40 that contacts the lens barrel 51 for positioning the lens 40 has an area equal to or larger than that of the flange 23 of the glass molded lens 20 , and the lens 40 can be positioned with high precision by the flange 42 .

[0108] Therefore, when it is desired to obtain the same positional accuracy and stability with the glass molded lens 20 and the lens 40 , the flange 42 of the lens 40 can be configured to be smaller and lighter than the flange 23 of the glass molded lens 20 .

[0109] The metal flange portion 42 can easily achieve a thinning degree that is difficult to process for the glass flange portion 23 formed integrally with the glass molded lens 20. For example, a structure such as a thin cylindrical portion 42a in a direction perpendicular to the optical axis and a thin annular portion 42b in the direction of the optical axis is difficult to form with high precision using glass, and even if it can be formed with glass, it will be easily damaged. In contrast, the metal flange portion 42 has the advantage of being easily formed into a thin and high-precision shape by pressing a metal plate. In addition, the metal flange portion 42 can restore its shape through elastic deformation to a certain degree of external force, so even if the flange portion 42 is thinned, the risk of rupture or irreversible deformation is low.

[0110] In the manufacture of the lens 40 using the lens molding mold 30 described above, the flange portion 42 having the barrel portion 42a and the annular portion 42b is held in the lower mold 32, and when the optical function portion 41 is press-molded, the flange portion 42 is plastically deformed and processed into a final shape. According to this manufacturing method, the shape accuracy of the lens surfaces 43 and 44 of the optical function portion 41 and the shape accuracy of the barrel portion 42a and the annular portion 42b of the flange portion 42 are managed together by the pressing surface (lens forming surface 34, annular portion holding surface 35, blocking convex portion 36) of the lower mold 32 and the pressing surface (lens forming surface 37, barrel portion forming surface 38, facing surface 39) of the upper mold 33, so the relative shape accuracy of the optical function portion 41 and the flange portion 42 and the shape accuracy of the lens 40 as a whole can be improved.

[0111] Furthermore, since the metal flange 42 is not light-transmissive, it is possible to obtain a light-shielding effect of shielding harmful light that passes through the outer sides of the lens surfaces 43 and 44 of the lens 40. Figure 4 In the glass molded lens 20, the flange 23 has light-transmitting properties, so it is necessary to apply a light-shielding coating or a light-shielding member to the flange 23. In contrast, in the lens 40, the flange 42 itself has light-shielding properties, so there is an advantage that such a labor is not required.

[0112] Furthermore, in order to improve the light-shielding property of the flange portion 42, the outer surface of the flange portion 42 may be subjected to a blackening treatment to suppress the reflection of light. The outer surface of the flange portion 42 refers to the portion of the flange portion 42 that appears in appearance in a single body state (the state before being combined with the optical functional portion 41). The inner circumference of the barrel portion 42a that is fixed relative to the outer circumference 45 of the optical functional portion 41 in a state where the lens 40 is completed is also included in the outer surface of the flange portion 42. The blackening treatment of the outer surface is a process used to prevent the color and gloss of the metal (base metal) that is the raw material of the flange portion 42 from being directly exposed on the outer surface, thereby reducing the reflection of light. In addition, in the blackening treatment, it is not limited to making the outer surface of the flange portion 42 completely black, as long as a reflection reduction effect of a prescribed level or higher is exerted compared to the case where the base metal of the flange portion 42 is exposed. Fig.12 and Fig.13 In FIG. 1 , a portion of the outer surface of the flange portion 42 that has been subjected to blackening treatment is indicated by a thick line.

[0113] Fig.12 This is an example of blackening the inner circumference of the cylinder 42a in the flange 42. By blackening the inner circumference of the cylinder 42a that constitutes the inner surface of the optical path surrounding the optical function part 41, the inner surface reflection generated by the inner circumference of the cylinder 42a can be suppressed, and the optical performance of the lens 40 can be improved.

[0114] Fig.13 This is an example of a flange portion 42 having its outer surface blackened as a whole, where the inner circumference, outer circumference, top end surface of the cylinder portion 42a, and the front, back, and outer edge of the annular portion 42b are all blackened. In other words, the flange portion 42 is configured so that the portion (base metal) that has not been blackened is not exposed to the outside. In order to improve the effect of suppressing harmful stray light in the thin flange portion 42, the outer surface may also be blackened as a whole.

[0115] In addition, if Fig.10 , Fig.11 When the lens 40 is assembled to the lens barrel 51 as shown, in a case where the outer peripheral surface of the barrel portion 42a of the flange portion 42 is in close contact with the small diameter cylindrical surface 55 of the lens barrel 51 so that light does not enter the outer peripheral surface of the barrel portion 42a, it is also possible to choose to blacken the inner peripheral surface of the barrel portion 42a and the entire annular portion 42b instead of blackening the outer peripheral surface of the barrel portion 42a.

[0116] It is difficult to perform blackening treatment on the inner circumference of the barrel portion 42a after the optical function portion 41 and the flange portion 42 are combined. Therefore, it is sufficient to perform blackening treatment on the inner circumference of the barrel portion 42a before the optical function portion 41 is press-formed using the lens molding mold 30, that is, when the flange portion 42 is a single body.

[0117] The outer circumferential surface and the top end surface of the cylinder 42a in the flange 42 and the entire annular portion 42b can also be subjected to blackening treatment after the optical function portion 41 and the flange 42 are combined. Therefore, the portion other than the inner circumferential surface of the cylinder 42a can be subjected to blackening treatment before the press molding of the optical function portion 41 of the lens molding mold 30, or can be subjected to blackening treatment after the press molding.

[0118] As a method for blackening the outer surface of the flange portion 42, for example, oxidation by heating of the metal, chemical conversion treatment, plating treatment, etc. can be applied. Oxidation by heating of the metal is carried out by heating in an environment containing oxygen, so that the outer surface of the flange portion 42 is oxidized, the metallic luster is eliminated and it is blackened. As an example of chemical conversion treatment, the flange portion 42 is immersed in an alkaline aqueous solution to form a black oxide film (iron oxide film) on the outer surface of the flange portion 42. As an example of plating treatment, plating processing such as black nickel plating and black chromium plating is performed on the outer surface of the flange portion 42. In addition, after the optical function portion 41 is press-formed by the lens molding mold 30, since heating for softening the optical function portion 41 is not performed, the heat resistance condition is relaxed. Therefore, in the blackening treatment after press molding, a method such as applying a black paint made of synthetic resin can also be used.

[0119] like Fig. 9 As shown in the figure, an information display portion 48 may be provided on the flange portion 42. As an example of the information display portion 48, a reference mark indicating the circumferential orientation of the lens 40, a serial number of a product, a two-dimensional code containing information such as the specifications of the lens 40, etc. can be applied. The flange portion 42 made of metal is easy to provide the information display portion 48, and it is also easy to improve the visibility of the information display portion 48. The front and back surfaces of the annular portion 42b in the optical axis direction, the outer peripheral surface of the cylindrical portion 42a, etc. are suitable as the locations for providing the information display portion 48.

[0120] The optical function part 41 of the lens 40 does not have the positioning function of the lens 40, but is a structure in which the lens surface 43 and the lens surface 44 functioning as optical surfaces are connected by a simple peripheral shape (peripheral surface 45, volume absorption part 46 and volume absorption part 47). Therefore, in the optical function part 41, there is no Figure 4 There is no thin protruding portion such as the flange portion 23 in the glass molded lens 20, and there is no portion where the angle of the surface changes sharply such as the boundary between the lens surface 21 and the first plane 23a in the glass molded lens 20. Compared with the glass molded lens 20, the risk of cracking and breakage is suppressed, which is advantageous in terms of strength.

[0121] Furthermore, in the lens molding mold 30, the flange portion 42 is disposed in the peripheral area of ​​the mold space S2, and the cylindrical portion 42a blocks the extension of the glass preform PF2 to the peripheral side of the mold space S2, so that during molding, the glass preform PF2 does not need to be extended in the narrow space on the peripheral side of the mold space S2. Therefore, the extension of the glass preform PF2 in the optical effective area (lens surface 43 and lens surface 44 formed by the lens forming surface 34 and the lens forming surface 37) requiring high quality in appearance and surface accuracy can be achieved at a relatively low temperature (a value close to the glass transition temperature of the glass preform PF2). As a result, the appearance and surface accuracy of the optical function portion 41 can be improved in quality.

[0122] Furthermore, since the optical function portion 41 does not have a portion that is easily broken, such as the flange portion 23, when the optical function portion 41 is formed by the lens molding mold 30, it is not necessary to provide a release film for suppressing breakage, or special surface treatment of the glass preform PF2 (or such measures can be reduced). As a result, the outer surface of the optical function portion 41 will not be cloudy or the surface accuracy will be unstable due to the release film or surface treatment, which is also conducive to the high quality of the appearance and surface accuracy of the optical function portion 41.

[0123] Figure 4 The lens surface 21 and the lens surface 22 of the glass molded lens 20 are Figure 8 The lens surface 43 and the lens surface 44 of the lens 40 are substantially the same in design shape, but by Figure 2 and Figure 6 By comparison, it can be seen that the amount of glass preform PF2 required for forming the optical function portion 41 of the lens 40 is less than that of the glass preform PF1 used to form the glass molded lens 20. In addition, a small amount of glass preform PF2 is a spherical body with a smaller radius of curvature than that of the glass preform PF1, so compared with the lens surface 21 and the lens surface 22 of the glass molded lens 20 made from the glass preform PF1, the lens surface 43 and the lens surface 44 of the lens 40 made from the glass preform PF2 reduce the risk of bubbles generated during pressing. In addition, by using a glass preform PF2 that is smaller than the glass preform PF1, the degree of freedom of the lens design shape can be increased.

[0124] As described above, the lens 40 of this embodiment is composed of a glass optical functional portion 41 and a flange portion 42 formed of a material different from the glass of the optical functional portion 41 (metal). This ensures the high optical performance and strength of the optical functional portion 41 while taking into account the compactness and lightness of the flange portion 42. Various advantages can be obtained compared with the glass molded lens 20 represented as a comparison object.

[0125] Furthermore, as described above, by configuring the flange portion 42 with the cylindrical portion 42 a and the annular portion 42 b , the flange portion 42 can be made thin and lightweight without impairing the positioning performance of the lens 40 .

[0126] More specifically, the following conditions are preferably satisfied in the lens 40 : First, only the flange portion 42 is provided with a function of positioning the lens 40 relative to a holding member such as the lens barrel 51 of the lens unit 50 .

[0127] The optical function part 41 only has a region including the lens surface 43 and the lens surface 44 as a part that performs an optical function, an outer peripheral surface 45 fixed to the flange part 42, and a volume absorption part 46 and a volume absorption part 47 for absorbing errors during press molding of the optical function part 41, and does not have a function of positioning the lens 40 relative to a holding member such as the lens barrel 51. As a condition on the shape of the optical function part 41, not only does it not have a function of determining the position of the lens, but it also does not include a surface orthogonal to the optical axis such as the front and back surfaces of the annular part 42b of the flange part 42. In other words, the optical function part 41 does not include a shape similar to the flange part of a known glass molded lens.

[0128] like Figure 8 As shown, in the flange portion 42, the length of the cylindrical portion 42a in the optical axis direction is L, and the width of the annular portion 42b in the direction perpendicular to the optical axis is W. Here, it is preferred that the following conditions (1) and (2) are satisfied:

[0129] (1)W / L≥0.8;

[0130] (2)W / L≤10.

[0131] The barrel 42a of the flange 42 has a function of being coupled with the outer peripheral surface 45 of the optical function part 41 to make the optical function part 41 and the flange 42 coaxial. Therefore, in order to achieve high-precision coupling with respect to the optical function part 41, the barrel 42a is required to have a length L in the optical axis direction that is greater than a predetermined value. In detail, the length L in the optical axis direction of the barrel 42a is preferably equal to the length in the optical axis direction of the outer peripheral surface 45 of the optical function part 41. When the barrel 42a is too short relative to the outer peripheral surface 45 of the optical function part 41, the coupling accuracy cannot be ensured, and there is a risk that the optical function part 41 and the flange 42 are not properly coaxial. Alternatively, when the lens molding die 30 is used for press molding, there is a risk that a part of the glass preform PF2 flows out to the outer peripheral side of the barrel 42a, and the shape accuracy of the optical function part 41 is reduced.

[0132] Here, when condition (1) is excluded, the width W of the annular portion 42b in the direction perpendicular to the optical axis is insufficient compared to the length L of the barrel portion 42a in the direction of the optical axis, and the posture of the annular portion 42b is unstable when it is abutted against the stopper surface 53 of the lens barrel 51, and there is a risk that the accurate position of the lens 40 cannot be determined. Therefore, it is required to satisfy condition (1) on the basis of ensuring a sufficient and necessary length L in the direction of the optical axis for the barrel portion 42a.

[0133] Regarding the condition (1), it is more preferable that W / L≥1.5 is satisfied. In the lens 40 of the present embodiment, the value of W / L is approximately 1.5.

[0134] The outer edge of the annular portion 42b is the outermost periphery of the lens 40, so the width W of the annular portion 42b in the direction perpendicular to the optical axis affects the diameter of the lens 40. When condition (2) is excluded, there is a risk that the width W of the annular portion 42b in the direction perpendicular to the optical axis is very large compared to the length L of the barrel 42a in the direction perpendicular to the optical axis, and the diameter of the lens 40 including the flange portion 42 is too large, which hinders the miniaturization of the optical device (lens barrel 51, etc.) that accommodates the lens 40. Alternatively, when the area of ​​the annular portion 42b in the direction perpendicular to the optical axis is too wide, the difficulty of the precision management (ensuring flatness, etc.) of the surface used for positioning the annular portion 42b becomes higher, and there is a risk of adversely affecting the positioning accuracy of the lens 40 using the annular portion 42b. Therefore, considering the miniaturization of the optical device equipped with the lens 40 and the ease of management of the positional accuracy of the lens 40 in the optical device, it is preferable to satisfy condition (2).

[0135] Regarding condition (2), it is more preferable that W / L≤5 is satisfied.

[0136] However, when there is sufficient space margin inside the optical device and the restriction on the diameter size of the lens 40 is not strict, the condition (2) does not have to be satisfied.

[0137] Furthermore, when the area of ​​the annular portion 42b in the direction perpendicular to the optical axis is large, the accuracy of the positioning portion can be easily managed by providing a positioning protrusion or the like at a specific portion of the annular portion 42b. Therefore, if such a countermeasure can be taken, condition (2) can also be eliminated.

[0138] As described above, by adopting the structure of the lens 40 of this embodiment and satisfying the conditions (1) and (2), the flange portion 42 can be made smaller and lighter than a conventional glass molded lens without impairing optical performance.

[0139] The thickness t1 and t2 (plate thickness) of the cylindrical portion 42a and the annular portion 42b constituting the flange portion 42 can be set to appropriate values ​​in consideration of ease of processing, strength, etc. The thickness t1 of the cylindrical portion 42a in the direction perpendicular to the optical axis and the thickness t2 of the annular portion 42b in the direction of the optical axis of the lens 40 of this embodiment are both about 0.5 mm.

[0140] When the thickness t1 of the barrel 42a and the thickness t2 of the annular portion 42b are too large, the lightweight effect brought by the weight-reducing structure of the flange 42 having an L-shaped cross section is reduced. In addition, when the flange 42 is plastically deformed by press molding using the lens molding mold 30, if the thickness t1 of the barrel 42a and the thickness t2 of the annular portion 42b are too large, it is difficult to deform, or irregular deformation (shrinkage, etc.) occurs, and there is a risk that the shape accuracy of the flange 42 after press molding will deteriorate.

[0141] When the thickness t1 of the barrel 42a and the thickness t2 of the annular portion 42b are too small, there is a risk that the rigidity of the flange portion 42 is insufficient, and the accuracy and strength required for holding the optical function portion 41 and positioning the lens 40 cannot be obtained. For example, when the barrel 42a is too thin, there is a risk that it may deform irregularly and impair the coaxiality with the optical function portion 41. When the annular portion 42b is too thin, there is a risk that it may deform irregularly and fail to properly position the lens 40.

[0142] like Figure 8 As shown, the diameter of the entire lens 40 defined by the outer edge of the annular portion 42b of the flange portion 42 is defined as the outer diameter D. The diameter of the optical function portion 41 defined by the inner circumferential surface of the cylindrical portion 42a of the flange portion 42 (the outer circumferential surface 45 of the optical function portion 41) is defined as the surface diameter d. The diameter of the portion of the optical function portion 41 excluding the radial region forming the volume absorption portion 46 and the volume absorption portion 47 (the diameter of the optically effective lens surfaces 43 and 44) ​​is defined as the effective diameter e. The dimension of the radial region forming the volume absorption portion 46 and the volume absorption portion 47 in the direction orthogonal to the optical axis is defined as the error absorption width R. The maximum thickness of the flange portion 42 in the optical axis direction is defined by the length L of the cylindrical portion 42a in the optical axis direction.

[0143] The outer diameter D and the length L of the tube portion 42a in the optical axis direction (the maximum thickness of the flange portion 42 in the optical axis direction) preferably satisfy the following conditions (3) or (4):

[0144] (3) When 2mm≤D≤5mm,

[0145] 0.15≤L≤0.35;

[0146] (4) When D>5mm,

[0147] 0.15+(D-5)×0.03≤L≤0.15+(D-5)×0.07.

[0148] Conditions (3) and (4) represent the range of the appropriate maximum thickness of the flange 42 in the optical axis direction relative to the diameter of the lens 40. If the lower limit of conditions (3) and (4) is exceeded, there is a risk of affecting the positioning accuracy of the lens 40, the stability of holding, the strength of the flange 42, etc.

[0149] When the upper limit of conditions (3) and (4) is exceeded, the flange portion 42 becomes thicker in the optical axis direction, and the requirement for thinness is not met. For example, when the length L of the barrel portion 42a in the optical axis direction is too large, when assembled to the lens barrel 51 of the lens unit 50, the space occupied by the flange portion 42 in the optical axis direction becomes too large, and there is a risk of enlarging the lens unit 50.

[0150] Thus, by satisfying conditions (3) and (4), the flange 42 can be made thinner while ensuring the strength and accuracy of the flange 42. In other words, by using the lens 40 formed of the optical function portion 41 and the flange 42, conditions (3) and (4) can be naturally satisfied.

[0151] In the glass molded lens 20 ( Figure 4 ), when the flange portion 23 is formed with a thickness corresponding to the range of conditions (3) and (4), the probability of cracks or shape defects occurring in the flange portion 23 or its periphery will increase, or the probability of reduced positioning accuracy of the lens via the flange portion 23 will increase.

[0152] As described above, by adopting the structure of the lens 40 of the present embodiment and satisfying the conditions (3) or (4), it is possible to achieve a reduction in the thickness of the flange portion 42 compared to a conventional glass molded lens without impairing the optical performance.

[0153] In addition, as an additional condition different from the above conditions (3) and (4), from the viewpoint of the movement accuracy and stability of the lens molding die 30 during press molding, the upper limit of the length L of the barrel portion 42a of the lens 40 in the optical axis direction is preferably 40% or less of the outer diameter D. In the case where the flange portion 42 has a thickness greater than the upper limit, when the flange portion 42 is arranged inside the lens molding die 30, the fitting length of the insertion portion 33a of the upper mold 33 and the inner peripheral surface 31a of the cylindrical mold 31 and the fitting length of the insertion portion 32a of the lower mold 32 and the inner peripheral surface 31a of the cylindrical mold 31 become smaller, and the risk of the upper mold 33 and the lower mold 32 tilting relative to the central axis X2 during press molding increases. In particular, since the smaller the outer diameter D of the lens 40 is, the easier it is for each part of the lens molding die 30 to become compact, this tendency is stronger. Therefore, by setting the length L of the cylindrical portion 42a in the optical axis direction to be less than the above upper limit value, the fitting length of each part of the lens molding die 30 can be ensured, and the processing accuracy of press molding can be improved.

[0154] In addition, regarding the optical function portion 41 of the lens 40 , the surface diameter d and the effective diameter e preferably satisfy any one of the following conditions (5), (6), (7), and (8).

[0155] (5) When 2 mm ≤ e ≤ 5 mm, (de) ≤ 0.5 mm;

[0156] (6) When 5 mm < e ≤ 10 mm, (de) ≤ 0.7 mm;

[0157] (7) When 10 mm < e ≤ 15 mm, (de) ≤ 0.9 mm;

[0158] (8) When 15mm<e≤20mm, (de)≤1.1mm.

[0159] Conditions (5), (6), (7), and (8) represent appropriate values ​​of the difference between the surface diameter d and the effective diameter e of the optical function portion 41. By satisfying any one of the conditions (5), (6), (7), and (8), the volume error within a range that can be assumed when the optical function portion 41 having a predetermined effective diameter e is press-molded can be reliably absorbed by the volume absorbing portion 46 and the volume absorbing portion 47, and the optical function portion 41 having the lens surface 43 and the lens surface 44 with high precision and appearance quality can be manufactured without causing molding defects.

[0160] In addition, if Figure 8 As shown, the difference between the surface diameter d and the effective diameter e of the lens 40 is substantially equal to the error absorption width R × 2. In addition, regarding the error absorption width R, it is preferable to satisfy the following conditions (9), (10), (11) or (12).

[0161] (9) When 2 mm ≤ D ≤ 5 mm, R ≤ 0.23 mm;

[0162] (10) When 5 mm < D ≤ 10 mm, R ≤ 0.35 mm;

[0163] (11) When 10 mm < D ≤ 15 mm, R ≤ 0.45 mm;

[0164] (12) When 15mm<D≤20mm, R≤0.55mm.

[0165] The dimension of the flange portion 42 in the direction perpendicular to the optical axis ( Figure 8 The width W of the annular portion 42b in the direction perpendicular to the optical axis shown can be obtained by (Dd) / 2. The lens 40 of this embodiment can realize the thinning of the flange portion 42, and a high degree of freedom is obtained in the dimensional relationship between the width W of the annular portion 42b in the direction perpendicular to the optical axis and the length L of the barrel portion 42a in the direction of the optical axis. By satisfying the following condition (13), it is easy to realize the lightweight of the lens 40 and the stabilization of the posture of the lens 40 when assembled into the lens barrel 51.

[0166] (13)0.5≤{(Dd) / 2} / L≤30.

[0167] The lower limit of {(Dd) / 2} / L in the range of condition (13) is preferably 1.0, more preferably 1.5, and even more preferably 2.0. In addition, the upper limit of {(Dd) / 2} / L in the range of condition (13) is preferably 20, more preferably 10, and even more preferably 5.

[0168] In the lens 40 of the above-mentioned embodiment, the material of the flange 42 is set to metal, but as the material of the flange of the lens to which the utility model is applied, a material other than metal can also be selected. For example, the flange can also be composed of ceramics. In this case, the thermal expansion coefficient of the ceramic constituting the flange is preferably higher than the thermal expansion coefficient of the material constituting the lens molding mold. Thus, when the optical function part of the lens is molded, the flange made of ceramic expands and fits tightly with the lens molding mold, and the eccentricity accuracy relative to the lens molding mold is improved, so that a lens in which the flange and the optical function part are coaxial with high precision can be obtained.

[0169] The flange portion 42 of the above embodiment has an L-shaped cross-sectional structure, and is formed into a shape in which an annular portion 42b is extended from one end of the barrel portion 42a in the optical axis direction, and the other end of the barrel portion 42a in the optical axis direction is completed as an end face facing the optical axis direction. The flange portion 42 of this shape has the advantage of being easy to manufacture by press working. However, a flange portion of a shape different from the flange portion 42 of the above embodiment can also be applied.

[0170] For example, as a modified example, an annular flange may be provided that protrudes from the other end of the cylindrical portion 42a in the optical axis direction (the end opposite to the end side where the annular portion 42b extends) toward the radial center side of the lens 40 (the side close to the optical axis Xb). In other words, the cross-sectional shape of the flange portion may not be Figure 8 The flange is shaped to cover a portion of the periphery of the optical function portion 41 (near the volume absorption portion 47), and can function as a light shielding portion that shields the travel of light reflected by the inner surface of the cylinder portion 42a.

[0171] As another modification, a flange portion having a structure (T-shaped cross-sectional structure) in which the annular portion 42b protrudes from a position in the middle of the tube portion 42a in the optical axis direction in a direction perpendicular to the optical axis can also be used. Figure 4 Compared with the flange portion 23 of the glass molded lens 20 shown in the figure, the effect of reducing size and weight can be obtained.

[0172] In addition, the surfaces (front and back) on both sides of the annular portion 42b of the flange portion 42 in the optical axis direction are parallel planes, but a depression or a notch may exist in a part of the annular portion 42b. In addition, the cylindrical portion 42a of the flange portion 42 in the above embodiment is a complete cylindrical shape that is continuous in the circumferential direction with the optical axis Xb as the center, and a depression or a notch may exist in the middle of the cylindrical portion 42a. In these cases, the outer diameter of the lens 40 and the size of the flange portion 42 are determined based on the remaining parts of each part of the flange portion 42 except the depression or the notch.

[0173] The implementation of the utility model is not limited to the above-mentioned implementation and its variants. Various changes, substitutions and deformations can be made within the scope of the technical purpose of the utility model. Furthermore, if the technical idea of ​​the utility model can be realized in another method through technological progress or another derived technology, the method can be used for implementation. Therefore, the scope of the claims covers all implementations that can be included in the scope of the technical idea of ​​the utility model.

[0174] Description of Reference Numerals

[0175] 30: Lens molding mold;

[0176] 31: cylindrical mold;

[0177] 32: lower die;

[0178] 33: Upper mold;

[0179] 34: lens forming surface;

[0180] 35: annular portion retaining surface;

[0181] 36: blocking convex part;

[0182] 37: lens forming surface;

[0183] 38: barrel forming surface;

[0184] 39: facing each other;

[0185] 40: Lens;

[0186] 41: optical function unit;

[0187] 42: flange portion;

[0188] 42a: barrel;

[0189] 42b: annular part;

[0190] 43: Lens surface;

[0191] 44: lens surface;

[0192] 45: outer peripheral surface;

[0193] 46: volume absorption part;

[0194] 47: volume absorption part;

[0195] 48: information display unit;

[0196] 50: lens unit;

[0197] 51: lens barrel;

[0198] 52: space inside the lens barrel;

[0199] 53: limit surface;

[0200] 54: Large diameter cylindrical surface;

[0201] 55: small diameter cylindrical surface;

[0202] 56: screw hole;

[0203] 57: through hole;

[0204] 58: screw;

[0205] L: The length of the barrel in the optical axis direction;

[0206] PF2: glass preform;

[0207] S2: mold space;

[0208] W: width of the annular portion in the direction perpendicular to the optical axis;

[0209] X2: the central axis of the lens molding mold;

[0210] Xb: optical axis;

[0211] t1: thickness of the barrel in the direction perpendicular to the optical axis;

[0212] t2: The thickness of the annular portion in the optical axis direction.

Claims

1. A lens, characterized in that: have: An optical function part which is a glass press-molded product having lens surfaces on both sides in the optical axis direction and a volume absorption part around the lens surfaces to allow for shape errors accompanying press molding; and a flange portion, which is combined with the optical function portion and is made of a material different from the glass of the optical function portion, The flange portion has: a cylindrical portion formed in a cylindrical shape with the optical axis as the center and surrounding the outer peripheral surface of the optical function portion and fixed thereto; and The annular portion has a thickness in the optical axis direction that is smaller than the length of the cylindrical portion in the optical axis direction, and is extended from the outer peripheral surface of the cylindrical portion in a direction perpendicular to the optical axis. The length L of the cylindrical portion in the optical axis direction and the width W of the annular portion in the direction perpendicular to the optical axis satisfy the following condition (1): (1)W / L≥0.

8.

2. The lens according to claim 1, characterized in that The length L of the cylindrical portion in the optical axis direction and the width W of the annular portion in the direction perpendicular to the optical axis satisfy the following condition (2): (2)W / L≤10.

3. The lens according to claim 1 or 2, characterized in that: The flange portion is made of metal.

4. The lens according to claim 1 or 2, characterized in that: The annular portion is provided to extend from one end of the outer peripheral surface of the cylindrical portion in the optical axis direction in a direction perpendicular to the optical axis.

5. The lens according to claim 1 or 2, characterized in that: The inner peripheral surface of the cylindrical portion of the flange portion is blackened.

6. The lens according to claim 1 or 2, characterized in that: The outer surfaces of the cylindrical portion and the annular portion of the flange portion are entirely blackened.

7. A lens molding mold, used for pressing and molding the lens according to claim 1 or 2, characterized in that: The lens molding mold comprises an upper mold and a lower mold, The lower mold comprises: an annular portion holding surface, which is located around a lens forming surface of the lens surface forming the optical function portion and holds the annular portion of the flange portion; and The annular blocking protrusion is located around the annular portion holding surface, protrudes upwards from the annular portion holding surface, and defines the outer edge position of the annular portion.

8. The lens molding mold according to claim 7, characterized in that: The upper mold comprises: a barrel portion forming surface which is located around a lens forming surface forming the lens surface of the optical function portion and defines a position of an outer peripheral surface of the barrel portion of the flange portion; and The facing surface is located around the cylindrical portion forming surface and faces the annular portion holding surface and the blocking convex portion of the lower mold.

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