Flanged lens

Abstract

Provided is technology capable of improving the weather resistance of a flanged lens. This flanged lens has: a lens having a convex curved surface; and an annular flange protruding from the entire outer periphery of the convex curved surface. The flanged lens has an annular light-shielding plate that constitutes at least a portion of the flange and extends along the entire outer periphery of the convex curved surface. The lens includes a transparent first glass. The light-shielding plate contains an inorganic material.

Description

Flange-mounted lens

[0001] The present disclosure relates to flanged lenses.

[0002] The flanged lens described in Patent Document 1 has a lens and a flange. The flanged lens is made of two different plastic materials (see

[0046] of Patent Document 1). A transparent plastic material is used for the active area of ​​the lens. A transparent glass material can also be used instead of the transparent plastic material (see

[0050] of Patent Document 1). A light-absorbing material is used for at least a portion of the flange.

[0003] International Publication No. 2020 / 118243

[0004] If the effective area of ​​the lens is made of plastic material, the optical characteristics will change significantly with temperature changes. Therefore, it is preferable that the effective area of ​​the lens is made of glass material. However, since the light-absorbing material that constitutes at least a part of the flange is made of plastic material, it is easily deteriorated by moisture.

[0005] An embodiment of the present disclosure provides a technique that can improve the weather resistance of a flanged lens.

[0006] A flanged lens according to one embodiment of the present disclosure includes a lens having a convex curved surface and an annular flange protruding from the entire outer periphery of the convex curved surface. The flanged lens also includes an annular light-shielding plate that forms at least a portion of the flange and follows the entire outer periphery of the convex curved surface. The lens includes a transparent first glass. The light-shielding plate includes an inorganic material.

[0007] According to an embodiment of the present disclosure, the weather resistance of a flanged lens can be improved.

[0008] FIG. 1(A) is a cross-sectional view of a flange-attached lens according to one embodiment, and FIG. 1(B) is a plan view of the flange-attached lens according to one embodiment. FIG. 2 is a cross-sectional view showing an example of a method for manufacturing the flange-attached lens shown in FIG. 1. FIG. 3(A) is a cross-sectional view of a flange-attached lens according to a first modified example, and FIG. 3(B) is a plan view of the flange-attached lens according to the first modified example. FIG. 4 is a cross-sectional view showing an example of a method for manufacturing the flange-attached lens shown in FIG. 3. FIG. 5(A) is a cross-sectional view of a flange-attached lens according to a second modified example, and FIG. 5(B) is a plan view of the flange-attached lens according to the second modified example. FIG. 6 is a cross-sectional view showing an example of a method for manufacturing the flange-attached lens shown in FIG. 5. FIG. 7(A) is a cross-sectional view of a flange-attached lens according to a third modified example, and FIG. 7(B) is a plan view of the flange-attached lens according to the third modified example. FIG. 8 is a cross-sectional view showing an example of a method for manufacturing the flange-attached lens shown in FIG. 7. FIG. 9(A) is a cross-sectional view of a flange-attached lens according to a fourth modified example, and FIG. 9(B) is a plan view of the flange-attached lens according to the fourth modified example. FIG. 10 is a cross-sectional view showing an example of a method for manufacturing the flanged lens shown in FIG.

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In each drawing, the same or similar components are denoted by the same reference numerals, and their description may be omitted. In the specification, the symbol "to" indicating a range of values ​​means that the values ​​before and after it are included as the lower and upper limits. The range of values ​​includes the range rounded up or down.

[0010] A flange-fitted lens 10 according to one embodiment will be described with reference to Figures 1(A) and 1(B). The flange-fitted lens 10 comprises a lens 20 having a convex curved surface 21 and an annular flange 30 protruding from the entire outer periphery of the convex curved surface 21. The lens 20 has an optical axis 20A. The optical axis 20A coincides with the normal to the convex curved surface 21 at the center of the convex curved surface 21. Hereinafter, the direction along the optical axis 20A may be referred to as the optical axis direction. The flange-fitted lens 10 is used, for example, in the optical system of an imaging device.

[0011] The flange-equipped lens 10 has an annular light-shielding plate 40 that forms at least a portion (the entire portion in this embodiment) of the flange 30. The light-shielding plate 40 fits along the entire outer periphery of the convex curved surface 21 of the lens 20. The flange 30 and the light-shielding plate 40 may be annular, and may be circular as shown in FIG. 1(B) or polygonal, although not shown. The light-shielding plate 40 blocks light. It is preferable that the light-shielding plate 40 absorbs light.

[0012] As shown in FIG. 1B, when viewed from the optical axis direction of the lens 20, the flanged lens 10 has a transmissive region A1 and a light-shielding region A2. The transmissive region A1 transmits light. The light-shielding region A2 blocks light. The light-shielding region A2 is an area where the light-shielding plate 40 is present. The light-shielding region A2 is formed to surround the transmissive region A1. In this embodiment, the light is visible light, but it may also be ultraviolet light or infrared light. In FIG. 1B, A3 is the boundary line between the light-shielding region A2 and the transmissive region A1.

[0013] 1A, the lens 20 has an opposite surface 22 facing opposite to the convex curved surface 21. In this embodiment, the opposite surface 22 is a convex curved surface, but it may also be a flat surface. That is, the lens 20 is a biconvex lens in this embodiment, but it may also be a plano-convex lens. Furthermore, the opposite surface 22 may be a flat surface that is inclined with respect to a plane perpendicular to the optical axis direction of the lens 20.

[0014] The lens 20 includes a transparent first glass. In this embodiment, the first glass constitutes the entire lens 20, but it may constitute at least a portion of the lens 20. The first glass may constitute at least the effective area of ​​the lens 20. The effective area of ​​the lens 20 is, for example, an area through which light passes to form an image on an imaging element of an imaging device. In this embodiment, the first glass does not constitute part of the flange 30, but may constitute part of the flange 30 (specifically, the transparent substrate 50) as shown in FIG. 5(A).

[0015] As described above, the lens 20 includes a transparent first glass. Generally, glass exhibits smaller changes in optical properties (e.g., refractive index and extinction coefficient) due to temperature changes than resin. The first glass is not particularly limited, but may be, for example, soda-lime glass, borosilicate glass, aluminosilicate glass, lead glass, optical glass, synthetic quartz glass, or crystallized glass.

[0016] The glass transition point (Tg1) of the first glass is preferably 800° C. or lower. If Tg1 is 800° C. or lower, the viscosity of the first glass can be sufficiently reduced at a temperature at which cemented carbide generally used as a mold for a press does not undergo plastic deformation, and the first glass can be deformed into a desired shape.

[0017] From the viewpoint of reducing the inclusion of air bubbles, the glass transition point (Tg1) of the first glass is preferably 750° C. or lower, more preferably 700° C. or lower, and even more preferably 650° C. or lower. From the viewpoint of feasibility, the glass transition point (Tg1) of the first glass is preferably 350° C. or higher.

[0018] The light blocking plate 40 constitutes at least a part of the flange 30 (in this embodiment, the entire flange 30). The light blocking plate 40 blocks light. Preferably, the light blocking plate 40 absorbs light. The light blocking plate 40 contains an inorganic material. Inorganic materials have better weather resistance than organic materials, and can improve the weather resistance of the flange-attached lens 10. Here, weather resistance includes resistance to moisture.

[0019] The light-shielding plate 40 preferably contains second glass as an inorganic material. The content of the second glass in the light-shielding plate 40 is preferably 50% by volume or more. When the light-shielding plate 40 mainly contains the second glass, the difference in the linear expansion coefficients of the multiple materials constituting the flange-attached lens 10 can be reduced. The second glass may be partially crystallized.

[0020] The second glass is preferably, for example, opaque black glass. The black glass contains, as a coloring component, metal ions that dissolve in the black glass. The black glass contains, as a coloring component, ions of at least one element selected from Fe, Cr, Mn, Co, Ni, Ti, V, and Cu. When the second glass is black glass, the light-shielding plate 40 is obtained by processing a block of black glass. The composition of the black glass is measured by X-ray fluorescence analysis (XRF).

[0021] Black glass contains, for example, SiO 2 in mass % on an oxide basis. ２ 50% to 75% Al ２ O ３ 0% to 15%, Na ２ O: 0% to 20%, K: ２ O 0% to 20%, MgO 0% to 15%, CaO 0% to 20%, B ２ O ３ 10% to 20%, ΣRO (R is Mg, Ca, Sr, Ba, Zn) 0% to 20%, ZrO ２ 0% to 5%, Fe ２ O ３ 1.0% to 10%, CoO 0% to 1%, SO ３ ΣRO is the total content of MgO, CaO, SrO, BaO and ZnO.

[0022] Black glass is V within the range that does not impair the color. ２ O ５ , CrO, MnO, CuO, MoO ３ and CeO ２ It may contain at least one selected from the following. ２ O ５ , CrO, MnO, CuO, MoO ３ , CeO ２ The total content of is preferably 0% to 3%, more preferably 0% to 1%, expressed in mass % on the oxide basis.

[0023] Black glass can be clarified using SO as a fining agent within the range that does not impair the color. ３ , Sb ２ O ３ , SnO, Cl, and F.３ , Sb ２ O ３ The total content of SnO, Cl and F is preferably 0% to 1%, and more preferably 0% to 0.5%.

[0024] The glass transition point (Tg2) of the second glass is preferably higher than the glass transition point (Tg1) of the first glass. Tg1 and Tg2 are measured using a differential thermal analysis (DTA). If the flange-attached lens 10 has a chemically strengthened layer, the chemically strengthened layer is removed to prepare a test powder for the glass transition point.

[0025] The chemically strengthened layer is a layer into which compressive stress is introduced by exchanging alkali metal ions (e.g., Na ions) contained in the first glass or the second glass with alkali metal ions (e.g., K ions) having a larger ionic radius at a temperature equal to or lower than the glass transition point (Tg1 or Tg2).

[0026] If Tg2 is higher than Tg1, the second glass is less likely to deform due to heat than the first glass. Therefore, when the first glass and the second glass are integrated while being heated, the first glass can be deformed into a desired shape while suppressing deformation of the hole in the light-shielding plate 40, and distortion of the hole in the light-shielding plate 40 can be reduced.

[0027] It is preferable that the ratio (Tg2 / Tg1) of the glass transition temperature (Tg2) of the second glass to the glass transition temperature (Tg1) of the first glass be 1.04 or more. If the ratio (Tg2 / Tg1) is 1.04 or more, the first glass can be deformed into a desired shape while suppressing deformation of the holes in the light-shielding plate 40. The ratio (Tg2 / Tg1) is more preferably 1.07 or more. The larger the ratio (Tg2 / Tg1), the more preferable it is. However, the ratio (Tg2 / Tg1) may be 1.20 or less.

[0028] The absolute value of the difference between the average linear expansion coefficient (CTE1) of the second glass and the average linear expansion coefficient (CTE2) of the first glass (ΔCTE=|CTE1-CTE2|) is 35.8×10 －７ / °C. ΔCTE is preferably less than 35.8 × 10 －７If ΔCTE is less than 23.0×10 / °C, the stress generated by temperature change is small and the glass is less likely to break. －７ / °C or less, and particularly preferably 16.0 × 10 －７ / °C or less. The smaller ΔCTE is, the more preferable, and it may be zero. When ΔCTE is not zero, either CTE1 or CTE2 may be larger.

[0029] The average linear expansion coefficients (CTE1 and CTE2) are the average linear expansion coefficients at 20°C to 300°C. The average linear expansion coefficients are measured using a thermal mechanical analysis (TMA). If the flange-attached lens 10 has a chemically strengthened layer, the chemically strengthened layer is removed to prepare a test specimen. The size of the test specimen is, for example, 5 mm in length, 5 mm in width, and 20 mm in height. If it is difficult to cut out a test specimen from one flange-attached lens 10, the test specimen may be prepared by melting material cut out from multiple flange-attached lenses 10.

[0030] In order to suppress reflection at the interface between the first and second glasses, it is preferable to select a second glass having a refractive index close to that of the first glass. Therefore, the second glass may be transparent like the first glass. The first and second glasses may have the same composition. However, if the second glass is black glass, the first and second glasses will naturally have different compositions.

[0031] When the second glass is transparent, the light-shielding plate 40 contains a pigment dispersed in the second glass. The pigment is dispersed in the second glass without forming a solid solution in the second glass. The light-shielding plate 40 is obtained by firing a glass paste containing powder of the second glass and the pigment. The glass powder is also called glass frit. The glass paste may contain additives other than the glass powder and the pigment, such as a resin binder. The resin binder is removed before firing the glass paste.

[0032] The pigment is, for example, a black pigment. The pigment is preferably an inorganic pigment. The inorganic pigment is, for example, a metal oxide, a metal, or a carbon-based material. The carbon-based material is graphite or carbon black. Graphite is crystalline, and carbon black is amorphous. Multiple types of pigments may be used to adjust the wavelength dependency of light transmittance.

[0033] The light blocking plate 40 has a constant thickness portion 41 that has a constant thickness in the optical axis direction of the lens 20. The light transmittance in the constant thickness portion 41 is preferably 0.1% or less. The light transmission can be sufficiently suppressed in the constant thickness portion 41. The thickness of the constant thickness portion 41 is preferably 1 μm or more in order to suppress the light transmittance in the constant thickness portion 41 to 0.1% or less.

[0034] In this embodiment, the light-shielding plate 40 is made up of only the constant-thickness portion 41, but as will be described later, it may have a tapered portion 42 (see FIG. 5A ) in addition to the constant-thickness portion 41. The maximum thickness of the tapered portion 42 is preferably equal to the thickness of the constant-thickness portion 41, but it may be greater than or less than the thickness of the constant-thickness portion 41.

[0035] It is preferable that the light blocking plate 40 is formed over the entire optical axis direction of the lens 20 in at least a portion (preferably the entire) of the flange 30. In other words, it is preferable that the light blocking plate 40 has the same thickness as the flange 30 in at least a portion (preferably the entire) of the flange 30. As shown in Figure 5(A) , compared to when the light blocking plate 40 is thinner than the flange 30, the light blocking plate 40 is more likely to absorb stray light leaking from the lens 20 to the flange 30.

[0036] A method for manufacturing a flange-attached lens 10 according to one embodiment will be described with reference to Fig. 2. The flange-attached lens 10 can be manufactured using a mold 100 and a press machine 200. The mold 100 includes a first mold 101 and a second mold 102. The press machine 200 opens and closes the first mold 101 and the second mold 102. For example, the first mold 101 is a lower mold, and the second mold 102 is an upper mold, and the press machine 200 raises and lowers the second mold 102.

[0037] With the first mold 101 and the second mold 102 open, an annular light-shielding plate 40 is placed on the first mold 101. The first glass G1 is placed inside the light-shielding plate 40. The shape of the first glass G1 is not particularly limited. Thereafter, the press machine 200 lowers the second mold 102, thereby deforming the first glass G1 into a desired shape.

[0038] The mold 100 is heated to assist the deformation of the first glass G1. The heating temperature of the mold 100 is preferably equal to or higher than the glass transition point (Tg1) of the first glass G1. The heating temperature of the mold 100 is preferably equal to or lower than the softening point (Ts1) of the first glass G1 by +100°C. Ts1 is higher than Tg1.

[0039] A flanged lens 10 according to a first modified example will be described with reference to Figures 3(A) and 3(B). Differences will be mainly described below. As shown in Figure 3(B), when viewed from the optical axis direction of the lens 20, the inner periphery 40a of the light-shielding plate 40 preferably extends inside the outer periphery 21a of the convex curved surface 21. The inner periphery 40a of the light-shielding plate 40 is the boundary line A3 between the transmission region A1 and the light-shielding region A2.

[0040] When viewed from the optical axis direction of the lens 20, the effective area of ​​the lens 20 is generally located inside the outer periphery 21a of the convex curved surface 21. If the inner periphery 40a of the light-blocking plate 40 is located inside the outer periphery 21a of the convex curved surface 21, the light-blocking plate 40 can easily absorb stray light leaking from the effective area of ​​the lens 20. When viewed from the optical axis direction of the lens 20, it is more preferable that the inner periphery 40a of the light-blocking plate 40 coincides with the outer periphery of the effective area of ​​the lens 20.

[0041] 3A, the inner periphery 40a of the light blocking plate 40 is preferably sandwiched between first glass pieces on both sides along the optical axis (i.e., on both the upstream and downstream sides in the light traveling direction). By sandwiching the inner periphery 40a of the light blocking plate 40, the first glass pieces prevent the light blocking plate 40 from peeling off.

[0042] A method for manufacturing a flanged lens 10 according to a first modified example will be described with reference to Fig. 4. As shown in Fig. 4, in this modified example, the flanged lens 10 can be manufactured using a mold 100 and a press machine 200, just like in the above embodiment. The inner periphery 40a of the annular light-shielding plate 40 is inserted into a space for molding the first glass G1 into a desired shape. As the first glass G1 deforms, it sandwiches the inner periphery 40a of the light-shielding plate 40 from both sides along the optical axis direction of the lens 20.

[0043] A flanged lens 10 according to a second modification will be described with reference to Figures 5(A) and 5(B). Differences will be mainly described below. The light-shielding plate 40 preferably has a tapered portion 42. The tapered portion 42 is provided on at least a portion (preferably the entirety) of the boundary line A3 between the light-shielding region A2 and the transmission region A1 when viewed from the optical axis direction of the lens 20.

[0044] The thickness of the tapered portion 42 in the optical axis direction of the lens 20 increases from the inner periphery 40a of the light-shielding plate 40 toward the outside. As a result, the light transmittance of the tapered portion 42 decreases as the distance from the boundary line A3 increases. Compared to when the light transmittance changes discontinuously at the boundary line A3, light diffraction can be suppressed, and the generation of stray light can be suppressed.

[0045] When the light blocking plate 40 has the tapered portion 42, the constant thickness portion 41 may be disposed farther from the boundary line A3 than the tapered portion 42. It is preferable that the constant thickness portion 41 has a constant transmittance in the optical axis direction of the lens 20.

[0046] The light-shielding plate 40 may be thinner than the flange 30. In this case, the light-shielding plate 40 may be formed in advance on the transparent substrate 50. The third glass constituting the transparent substrate 50 preferably has the same composition as the first glass. Note that the third glass may have a different composition from the first glass as long as it is transparent. The third glass may have a higher glass transition point than the first glass so that the transparent substrate 50 does not deform when the first glass is formed. The third glass may have a different composition from the second glass.

[0047] As shown in FIG. 5A , the light-shielding plate 40 is provided on only one surface of the transparent substrate 50 (e.g., the surface where light enters or exits), but it may also be provided on at least one of the opposite surface, the outer surface, and the inner surface of the transparent substrate 50 in addition to one surface of the transparent substrate 50. However, if a portion of the light-shielding plate 40 is provided on the inner surface of the transparent substrate 50, the light-shielding plate 40 does not need to have a tapered portion 42. That is, the light-shielding plate 40 only needs to occupy at least a portion of the flange 30. When the light-shielding plate 40 occupies a portion of the flange 30, the position of the light-shielding plate 40 within the flange 30 may be arbitrary, and it is preferable that the light-shielding plate 40 be formed at any position that forms an annular shape as a whole. For example, portions that become the light-shielding plate 40 may be formed on portions of one surface and the other surface of the flange 30 in the optical axis direction, and the portions that become the light-shielding plate 40 as a whole may form an annular light-shielding area that captures the effective area.

[0048] A method for manufacturing the flange-attached lens 10 according to the second modified example will be described with reference to Fig. 6. As shown in Fig. 6, in this modified example, the flange-attached lens 10 can be manufactured using a mold 100 and a press machine 200, just like in the above embodiment. It is preferable that the first glass G1 is molded after the light-shielding plate 40 is formed on the transparent substrate 50.

[0049] A flanged lens 10 according to a third modification will be described with reference to Figures 7(A) and 7(B). Differences will be mainly described below. The light-shielding plate 40 preferably has a gradient concentration portion 43. The gradient concentration portion 43 is provided on at least a portion (preferably the entirety) of the boundary line A3 between the light-shielding region A2 and the transmission region A1 when viewed from the optical axis direction of the lens 20.

[0050] In the concentration gradient portion 43, the concentration of the coloring component increases from the inner periphery 40a of the light-shielding plate 40 toward the outside. The coloring component is, for example, a pigment. The pigment is separated from the second glass and dispersed in the second glass. The coloring component may be a metal ion that is solid-dissolved in the second glass.

[0051] As described above, the concentration gradient portion 43 is in contact with the boundary line A3, and the concentration of the coloring component increases with increasing distance from the boundary line A3. As a result, the light transmittance decreases with increasing distance from the boundary line A3 in the concentration gradient portion 43. This makes it possible to suppress light diffraction and the generation of stray light.

[0052] Unlike the tapered portion 42, the concentration gradient portion 43 may have a constant thickness regardless of the distance from the boundary line A3. However, similar to the tapered portion 42, the concentration gradient portion 43 may have a thickness that increases with increasing distance from the boundary line A3.

[0053] The light-shielding plate 40 may have a constant density portion 44 in addition to the gradient density portion 43. The constant density portion 44 has a constant density of the coloring component regardless of the distance from the boundary line A3. The constant density portion 44 may have a constant thickness as well as a constant density. The constant density portion 44 may be positioned farther from the boundary line A3 than the gradient density portion 43.

[0054] A method for manufacturing a flanged lens 10 according to a third modified example will be described with reference to Fig. 8. As shown in Fig. 8, in this modified example, as in the above embodiment, a flanged lens 10 can be manufactured using a mold 100 and a press machine 200. An annular light-shielding plate 40 is placed on a first mold 101, and after the first glass G1 is placed inside the light-shielding plate 40, the first glass G1 is deformed into a desired shape.

[0055] A flanged lens 10 according to a fourth modification will be described with reference to Figures 9(A) and 9(B). Differences will be mainly described below. The light-shielding plate 40 has an inorganic multilayer film 45. The inorganic multilayer film 45 is formed on a transparent substrate 50 by a PVD (Physical Vapor Deposition) method such as sputtering or a CVD (Chemical Vapor Deposition) method.

[0056] As shown in FIG. 9A, the inorganic multilayer film 45 has multiple inorganic layers 46, 47, and 48 made of different materials. The inorganic layer 46 is, for example, an absorbing layer that absorbs light of a desired wavelength. The absorbing layer is preferably a metal layer, a semimetal layer, or a semiconductor layer. The number of absorbing layers does not have to be one, but may be two or more. The absorbing layer may have a metallic luster. Therefore, it is preferable to use the absorbing layer in combination with an anti-reflection layer.

[0057] The inorganic layers 47 and 48 are, for example, anti-reflection layers that prevent light reflection. The anti-reflection layer has a refractive index different from that of the absorption layer. The difference in refractive index can be utilized to prevent light reflection. The anti-reflection layer is preferably a dielectric layer. The material of the dielectric layer is preferably an oxide, nitride, fluoride, phosphide, sulfide, arsenide, selenide, antimonide, or telluride, and more preferably an oxide or nitride. The oxide may be, for example, Al. ２ O ３ Examples of fluorides include MgF ２ The number of dielectric layers does not have to be two, but may be one, or three or more.

[0058] The antireflection layer prevents the reflection of light, thereby preventing the generation of stray light. The antireflection layer is preferably provided on both sides of the absorbing layer. However, if light is incident on only one side of the absorbing layer, the antireflection layer may be provided only on one side of the absorbing layer.

[0059] The inorganic layers 46, 47, and 48 preferably contain at least one metal element or semimetal element selected from Cr, Ni, Ti, Nb, Ta, Si, Mo, and Zr. For example, the inorganic layer 46 is a Cr layer, and the inorganic layer 47 is a Cr layer. ２ O ３ layer, and the inorganic layer 48 is SiO ２ It is a layer.

[0060] Cr, Ni, Ti, Nb, Ta, Si, Mo, and Zr have small average linear expansion coefficients, which reduces the difference in average linear expansion coefficients among the materials that make up the flange-attached lens 10, improving the durability of the flange-attached lens 10 against temperature changes. The average linear expansion coefficient of the inorganic multilayer film 45 is represented by αave below.

[0061] αave is the sum of αi × di / Σ(di), where i is a natural number between 1 and n. n is the total number of inorganic layers constituting the inorganic multilayer film 45. di is the thickness (nm) of the i-th inorganic layer. Σ(di) is the total thickness (nm) of the first to n-th inorganic layers. αi is the average linear expansion coefficient (ppm / °C) of the i-th inorganic layer at 20°C to 300°C.

[0062] αave is preferably 3 ppm / °C to 15 ppm / °C. If αave is within the above range, the difference in the average linear expansion coefficients of the multiple materials constituting the flange-attached lens 10 can be reduced, and the durability of the flange-attached lens 10 against temperature changes can be improved. αave is more preferably 5 ppm / °C to 12 ppm / °C.

[0063] It is preferable that two adjacent inorganic layers constituting the inorganic multilayer film 45 do not contain the same metal element but different valences, or the same metalloid element but different valences. For example, in this embodiment, the Cr layer and the CrO layer are adjacent to each other, but it is preferable that they are not adjacent to each other. This prevents changes in valence due to element diffusion.

[0064] Although not shown, the inorganic multilayer film 45 may form the tapered portion 42 shown in Fig. 5A. If the inorganic multilayer film 45 is formed using an overhanging mask, the tapered portion 42 can be formed by the inorganic multilayer film 45.

[0065] In the tapered portion 42, the thickness of each of the inorganic layers 46, 47, and 48 increases with increasing distance. However, only some of the inorganic layers (e.g., the absorption layer) may have varying thicknesses in the tapered portion 42, and the remaining inorganic layers (e.g., the anti-reflection layer) may have a constant thickness. This is because a change in the thickness of the anti-reflection layer reduces the anti-reflection function.

[0066] A method for manufacturing a flange-attached lens 10 according to the fourth modified example will be described with reference to Fig. 10. As shown in Fig. 10, in this modified example, as in the above embodiment, the flange-attached lens 10 can be manufactured using a mold 100 and a press machine 200. It is preferable that the first glass G1 is molded after the light-shielding plate 40 is formed on the transparent substrate 50.

[0067] The light-shielding plate 40 of the fourth modified example has only (A) the inorganic multilayer film 45, but may also have (B) a sintered body of transparent glass powder and pigment or (C) black glass in addition to the (A) inorganic multilayer film 45. The light-shielding plate 40 may have any combination of two or more (including three) selected from (A) the inorganic multilayer film 45, (B) a sintered body of transparent glass powder and pigment, and (C) black glass.

[0068] The flanged lens according to the present disclosure has been described above, but the present disclosure is not limited to the above-described embodiments. Various changes, modifications, substitutions, additions, deletions, and combinations are possible within the scope of the claims. These naturally fall within the technical scope of the present disclosure.

[0069] 10 Lens with flange 20 Lens 30 Flange 40 Light shielding plate

Claims

1. A flanged lens having a lens with a convex curved surface and an annular flange protruding from the entire outer periphery of the convex curved surface, and an annular light-shielding plate that forms at least a part of the flange and follows the entire outer periphery of the convex curved surface, wherein the lens includes a transparent first glass, and the light-shielding plate includes an inorganic material.

2. A flanged lens according to claim 1, wherein the inner periphery of the light blocking plate is recessed inside the outer periphery of the convex curved surface when viewed in the direction of the optical axis of the lens.

3. A flanged lens according to claim 2, wherein the inner periphery of the light blocking plate is sandwiched by the first glass from both sides along the optical axis direction.

4. A flanged lens according to claim 1, wherein the light blocking plate is formed over the entire optical axis direction of the lens in at least a portion of the flange.

5. A flanged lens according to claim 1, wherein the light-shielding plate includes a second glass as the inorganic material.

6. The flanged lens according to claim 5, wherein the light-shielding plate contains, as a coloring component, metal ions that are solid-dissolved in the second glass.

7. The glass transition point (Tg2) of the second glass is higher than the glass transition point (Tg1) of the first glass, and the absolute value ΔCTE (ΔCTE = |CTE1-CTE2|) of the difference between the average linear expansion coefficient (CTE2) of the second glass and the average linear expansion coefficient (CTE1) of the first glass is 35.8 × 10 －７ 7. The flanged lens of claim 6, wherein the temperature is less than 100°C.

8. The flange-equipped lens according to claim 7, wherein the ratio (Tg2 / Tg1) of the glass transition point (Tg2) of the second glass to the glass transition point (Tg1) of the first glass is 1.04 or more.

9. A flanged lens according to claim 5, wherein the light-shielding plate contains, as a coloring component, a pigment that is separate from the second glass and dispersed in the second glass.

10. The flanged lens according to claim 1, wherein the light-shielding plate includes an inorganic multilayer film.

11. A flanged lens according to claim 1, wherein the light-shielding plate has a tapered portion in which the thickness in the optical axis direction of the lens increases from the inner periphery of the light-shielding plate toward the outer periphery.

12. A flanged lens according to claim 1, wherein the light-shielding plate contains a coloring component, and the light-shielding plate has a concentration gradient portion in which the concentration of the coloring component increases from the inner periphery of the light-shielding plate toward the outer periphery.

13. The flanged lens according to claim 1, wherein the light-shielding plate has an inorganic multilayer film.

14. The flange-equipped lens according to claim 13, wherein the inorganic multilayer film has a plurality of inorganic layers made of different materials.

15. A flange-equipped lens as described in claim 13, wherein the plurality of inorganic layers comprises an absorption layer that absorbs light of a desired wavelength and an anti-reflection layer having a refractive index different from that of the absorption layer, and the anti-reflection layers are provided on both sides of the absorption layer.

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