Optical system

Abstract

The optical system includes a compound lens including a first lens and a second lens. The first lens is made of resin, and the second lens is made of glass. When the maximum value of the thickness of the first lens is A [mm] and the minimum value of the thickness of the first lens is B [mm], the optical system satisfies conditional expressions (1) and (2). When the amount of plastic deformation when the indenter is pressed in at a load rate of 200 mN / 10 sec in a state where the ambient temperature is 25 DEG C is x [[mu] m], the resin satisfies conditional expression (3). A / B < = 10 (1) A < = 3mm (2) 1.0 [mu] m < = x < = 4.0 [mu] m (3)

Description

Technical Field

[0001] The technology of the present invention relates to an optical system including a compound lens. Background Art

[0002] Japanese Patent No. 6824424 discloses a device for manufacturing a composite lens including a base lens and a resin layer covering an optical surface shape of an optical surface of the base lens.

[0003] Japanese Patent Publication No. 07-68568 discloses a method for molding a composite optical element, wherein an energy-curable resin placed on a substrate of the optical element is pressed with a mold having a molding mask having a desired optical shape to form a resin layer, and energy is irradiated to cure the resin layer.

[0004] Japanese Patent Application Laid-Open No. 07-112491 discloses a composite optical element having aspherical resin layers made of a thermopolymerizable resin on both surfaces of a glass substrate.

[0005] Japanese Patent Application Publication No. 08-258172 discloses a method for manufacturing a plastic lens, wherein the plastic lens is molded by the following steps: a first step of partially polymerizing a specific plastic lens composition by active energy rays to make it non-fluidized; and a second step of terminating the polymerization by a heat treatment subsequent to the first step.

[0006] International Publication No. 2022 / 039143 discloses a compound capable of obtaining a cured product having a sufficiently low Abbe number and excellent transmittance, a curable resin composition containing the compound, a cured product obtained from the curable resin composition, and an optical component and a lens containing the cured product.

[0007] In Japanese Patent Gazette No. 2009-248483, a method for manufacturing a composite optical element is disclosed, the method comprising: a first discharging step of discharging a first resin onto an optical element substrate or a mold; a first irradiation step of irradiating the first resin with curing energy to cure it; a second discharging step of further discharging a second resin on the surface of the cured first resin; a stretching step of bringing the optical element substrate or the mold close to the second resin and expanding the second resin; and a second irradiation step of irradiating the expanded second resin with curing energy to cure it.

[0008] Japanese Patent Application Laid-Open No. 2003-262708 discloses a composite optical element including an element substrate and a resin layer fixed to the surface of the element substrate.

[0009] Japanese Patent Gazette No. 3071277 discloses a method for manufacturing a lens, the method being as follows: using as a base material a glass component consisting of a roughly circular plate-shaped main body and a trunk portion connected to the outer periphery of the main body in a manner that surrounds the outer periphery, and forming a resin layer having a prescribed surface shape by molding on an optical functional surface formed on the surface of the main body and having an outer diameter smaller than the outer diameter of the main body, thereby forming a lens in which glass material and resin material are integrated.

[0010] Japanese Patent No. 4632942 discloses a resin-bonded optical element including an optical element substrate and a resin layer bonded to the optical element substrate.

[0011] In Japanese Patent Gazette No. 2011-186440, a composite optical element is disclosed, which comprises: a glass substrate having a first optical functional surface on one side facing the optical axis direction and a second optical functional surface on the other side facing the optical axis direction, and having an outer peripheral surface arranged around the first optical functional surface; and a resin layer bonded to the second optical functional surface of the glass substrate.

[0012] Japanese Patent Application Laid-Open No. 05-323104 discloses a composite aspherical lens in which a synthetic resin layer having an aspherical surface is adhered and molded on the surface of a glass lens.

[0013] Japanese Patent Application Laid-Open No. 2005-060696 discloses a resin composition for a hybrid lens. The resin composition for forming a resin layer of a hybrid lens in which a resin layer is bonded to a glass lens base material contains a radical polymerizable monomer and a silane coupling agent.

[0014] Japanese Patent Application Laid-Open No. 2003-191260 discloses a device in which one surface of a glass lens is used as a resin film bonding surface and a transparent resin film is bonded to the resin film bonding surface so that the lens has predetermined characteristics.

[0015] In Japanese Patent Gazette No. 2018-151420, a lens structure is disclosed, wherein a first resin layer having an indentation elastic modulus at room temperature greater than 0MPa and less than 3000MPa is provided on a support body, a second resin layer is provided on the first resin layer, and the warping amount of the support body is 0μm to 50μm.

[0016] Japanese Patent Application Laid-Open No. 2015-219422 discloses an optical component composed of a substrate and a resin, wherein a specific formula is satisfied when the thinnest resin thickness of a main structure pattern composed of the resin is RTmin and the thickest resin thickness is RTmax. Summary of the invention

[0017] One embodiment of the technology according to the present invention provides an optical system capable of ensuring the quality of a first lens.

[0018] Means for solving technical problems

[0019] A first aspect of the technology of the present invention is an optical system including a composite lens having a first lens and a second lens, wherein:

[0020] When the first lens is formed of resin and the second lens is formed of glass, and the maximum value of the thickness of the first lens is A [mm] and the minimum value of the thickness of the first lens is B [mm],

[0021] The optical system satisfies the following conditional expressions (1) and (2):

[0022] A / B≤10 (1)

[0023] A≤3mm (2)

[0024] When the plastic deformation amount when the indenter is pressed at a load rate of 200 mN / 10 sec at an ambient temperature of 25°C is defined as x [μm],

[0025] The resin satisfies the conditional formula (3) represented by the following,

[0026] 1.0μm≤x≤4.0μm (3).

[0027] A second aspect of the technology of the present invention is, in the optical system according to the first aspect,

[0028] Satisfying the following conditional expressions (5) and (6),

[0029] A≥0.1mm (5)

[0030] B ≥ 0.02 mm (6).

[0031] A third aspect according to the technology of the present invention is the optical system according to the first aspect or the second aspect, wherein the hardness of the resin at 25° C. is 186 MPa or more and 196 MPa or less.

[0032] A fourth aspect according to the technology of the present invention is the optical system according to any one of the first to third aspects, wherein the hardness of the resin at 75° C. is 149 MPa to 164 MPa.

[0033] A fifth aspect according to the technology of the present invention is the optical system according to any one of the first to fourth aspects, wherein the elastic recovery factor of the resin at 75° C. is 59% or more and 63% or less.

[0034] A sixth aspect according to the technology of the present invention is the optical system according to any one of the first to fifth aspects, wherein the indentation elastic modulus of the resin at 25° C. is 3.5 GPa or more and 3.6 GPa or less.

[0035] A seventh aspect according to the technology of the present invention is the optical system according to any one of the first to sixth aspects, wherein the indentation elastic modulus of the resin at 75° C. is 2.4 GPa or less.

[0036] An eighth aspect according to the technology of the present invention is the optical system according to any one of the first to seventh aspects, wherein the resin has photocurability and thermosetting properties.

[0037] A ninth aspect of the technology of the present invention is an optical system according to any one of the first to eighth aspects, wherein the first lens is a lens having positive refractive power and formed of a resin, the center thickness of the first lens is d, the radius of curvature of the surface on the object side of the first lens is Rf, and the radius of curvature of the surface on the image side of the first lens is Rr.

[0038] The optical system satisfies the conditional equation (7) expressed as follows:

[0039] 0<d×(1 / Rf-1 / Rr)<0.05 (7).

[0040] A tenth aspect of the technology of the present invention is an optical system according to any one of the first to ninth aspects, comprising a front group, an aperture stop and a rear group, the front group, the aperture stop and the rear group being arranged in the order of the front group, the aperture stop and the rear group from the object side to the image side, the rear group including at least one Lp lens having positive power and formed of resin, the first lens being the Lp lens, the sum of the distance on the optical axis from the lens surface of the front group closest to the object side to the lens surface of the rear group closest to the image side in a state of focusing on an infinitely distant object and the air-converted distance on the optical axis from the lens surface of the rear group closest to the image side to the image plane being TL, and when the focal length of the Lp lens is fp,

[0041] The optical system satisfies the conditional equation (8) expressed as follows:

[0042] 0.1<TL / fp<1.2 (8).

[0043] The 11th mode involved in the technology of the present invention is an optical system involved in any one of the 1st mode to the 10th mode, comprising a front group, an aperture stop and a rear group, the front group, the aperture stop and the rear group are arranged in the order of the front group, the aperture stop and the rear group from the object side to the image side, the rear group includes at least one Lp lens having positive power and formed of resin, the first lens is the Lp lens, and the height of the principal ray of the maximum half angle of view on the surface of the object side of the Lp lens in a state of focusing on an infinitely distant object from the optical axis is set to Hpp, and the height of the on-axis marginal ray on the surface of the object side of the Lp lens in a state of focusing on an infinitely distant object from the optical axis is set to Hpm.

[0044] The optical system satisfies the conditional equation (9) expressed as follows:

[0045] 0.2<Hpp / Hpm<1.1 (9).

[0046] A twelfth aspect of the present invention is an optical system according to any one of the first to eleventh aspects, comprising a front group, an aperture stop, and a rear group.

[0047] The front group, the aperture stop, and the rear group are arranged in this order from the object side to the image side, the rear group includes at least one Lp lens having positive power and formed of resin, the first lens is the Lp lens, the radius of curvature of the image side surface of the Lp lens is set to Rr, when the point on the optical axis located at the position of the aperture stop is set to the object point in a state of focusing on an infinitely distant object, the distance on the optical axis from the image point formed by the optical system from the lens surface adjacent to the image side of the aperture stop to the image side surface of the Lp lens is set to De, and the medium closer to the image side than the image side surface of the Lp lens is calculated as air, and on the optical axis, if the image point is located at a position closer to the object side than the image side surface of the Lp lens, the sign of De is set to negative, and if the image point is located at a position closer to the image side than the image side surface of the Lp lens, the sign of De is set to positive,

[0048] The optical system satisfies the conditional equation (10) expressed as follows:

[0049] -0.9<(De-Rr) / (De+Rr)<0.9 (10).

[0050] A thirteenth aspect of the present invention is an optical system according to any one of the first to twelfth aspects, comprising a front group, an aperture stop, and a rear group.

[0051] The front group, the aperture stop, and the rear group are arranged in this order from the object side to the image side. The rear group includes at least one Lp lens having positive power and formed of resin. The first lens is the Lp lens. When the focal length of the focus group moving along the optical axis during focusing is denoted as ffoc and the focal length of the Lp lens is denoted as fp,

[0052] The optical system satisfies the conditional equation (11) represented by the following:

[0053] 0.04<ffoc / fp<0.36 (11).

[0054] A 14th aspect of the technology of the present invention is an optical system according to any one of the 1st to 13th aspects, comprising a front group, an aperture stop, and a rear group.

[0055] The front group, the aperture stop, and the rear group are arranged in this order from the object side to the image side. The first lens is an Lp lens formed of resin having positive refractive power. When the maximum angle of view in the state of focusing on an object at infinity is ωm,

[0056] When the conditional expression (12) expressed by the following is satisfied, the rear group includes the Lp lens,

[0057] ωm≥45° (12)

[0058] When the conditional expression (13) expressed by the following is satisfied, the front group includes the Lp lens

[0059] ωm<45° (13).

[0060] A fifteenth aspect of the present invention is an optical system according to any one of the first to fourteenth aspects, comprising a front group, an aperture stop, and a rear group.

[0061] The front group, the aperture stop and the rear group are arranged in this order from the object side to the image side, the rear group includes at least one Lp lens having positive power and formed of resin, the first lens is the Lp lens, the center thickness of the Lp lens is set to A, the thickness of the composite lens in the optical axis direction at the maximum effective diameter height on both surfaces of the Lp lens is set to B, the maximum image height is set to Y, the partial dispersion ratio between the g line and the F line of the Lp lens is set to θgF, the Abbe number of the d line reference of the Lp lens is set to νd, and ΔθgF is expressed by conditional expression (15):

[0062] ΔθgF=θgF-(0.6438-0.001682×vd) (14)

[0063] The optical system satisfies the conditional equation (16) expressed as follows,

[0064] 0.004<(|AB|ΔθgF) / Y<0.020 (15).

[0065] A 16th aspect of the technology of the present invention is an optical system according to any one of the 1st to 15th aspects, comprising a front group, an aperture stop, and a rear group.

[0066] The front group, the aperture stop and the rear group are arranged in this order from the object side to the image side, the composite lens is included in the front group, and the second lens is arranged on the object side relative to the first lens.

[0067] A 17th aspect of the present invention is an optical system according to any one of the 1st to 15th aspects, comprising a front group, an aperture stop, and a rear group.

[0068] The front group, the aperture stop and the rear group are arranged in this order from the object side to the image side, the compound lens is included in the rear group, and the second lens is arranged on the image side relative to the first lens.

[0069] The 18th embodiment of the technology involved in the present invention is an optical system, which includes a composite lens having a first lens and a second lens, wherein the first lens has a convex surface and a first surface protruding radially outward from the outer peripheral edge of the convex surface of the composite lens, and the second lens has a concave surface bonded to the convex surface and a second surface protruding radially outward from the outer peripheral edge of the concave surface and bonded to the first surface, and when the length of the first surface along the radial direction is set to a [μm], the length of the second surface along the radial direction is set to b [μm], and the surface roughness of the second surface is set to Ra [μm],

[0070] The optical system satisfies the following conditional expressions (16) and (17):

[0071] a<b (16)

[0072] 5μm≤a / Ra (17). BRIEF DESCRIPTION OF THE DRAWINGS

[0073] Figure 1 It is a longitudinal sectional view showing an example of a compound lens.

[0074] Figure 2 This is a longitudinal sectional view showing an example of the dimensional relationship of a compound lens.

[0075] Figure 3 It is an explanatory diagram showing an example of a method for manufacturing a compound lens.

[0076] Figure 4 This is a longitudinal sectional view for explaining an example of the problem of the compound lens.

[0077] Figure 5This is a graph showing an example of a load-displacement curve in a micro-hardness test.

[0078] Figure 6 It is a longitudinal sectional view showing an example of an imaging lens.

[0079] Figure 7 It is a longitudinal sectional view showing an example of the distance De in the imaging lens.

[0080] Figure 8 It is a longitudinal sectional view showing an example of the height Hpp and the height Hpm in the imaging lens.

[0081] Fig. 9 This is a longitudinal sectional view showing an example of the imaging lens according to Example 1.

[0082] Fig.10 These are explanatory diagrams showing various aberrations of the imaging lens according to Example 1.

[0083] Fig.11 This is a longitudinal sectional view showing an example of an imaging lens according to Example 2.

[0084] Fig.12 It is an explanatory diagram showing various aberrations of the imaging lens according to Example 2. DETAILED DESCRIPTION

[0085] Hereinafter, an example of an embodiment of an optical system according to the technology of the present invention will be described with reference to the drawings.

[0086] In the description of this specification, "orthogonal" means orthogonal in the sense of including errors that are generally allowed in the technical field to which the technology of the present invention belongs and errors that do not violate the main purpose of the technology of the present invention, in addition to being completely orthogonal. In the description of this specification, "parallel" means parallel in the sense of including errors that are generally allowed in the technical field to which the technology of the present invention belongs and errors that do not violate the main purpose of the technology of the present invention, in addition to being completely parallel. In the description of this specification, "plane" means a plane in the sense of including errors that are generally allowed in the technical field to which the technology of the present invention belongs and errors that do not violate the main purpose of the technology of the present invention, in addition to being completely flat.

[0087] (Structure of compound lens)

[0088] First, an example of the structure of the compound lens 10 is described. As an example, Figure 1 As shown, the compound lens 10 includes a first lens 12 and a second lens 14. The first lens 12 and the second lens 14 are both formed in a circular shape when viewed in the optical axis direction of the compound lens 10. The first lens 12 is formed of resin, and the second lens 14 is formed of glass.

[0089] As an example, the first lens 12 is a concave meniscus lens and has a convex surface 16 and a concave surface 18. The convex surface 16 is formed in a convex shape, and the concave surface 18 is formed in a concave shape. The concave surface 18 is a surface located on the opposite side of the convex surface 16 in the optical axis direction of the compound lens 10. The convex surface 16 and the concave surface 18 are formed in a lens body 20 in the first lens 12. The lens body 20 is a portion that defines the effective diameter of the first lens 12.

[0090] Furthermore, the first lens 12 has a flange 22. The flange 22 protrudes from the outer peripheral edge of the lens body 20 toward the radial outer side of the compound lens 10. The flange 22 is formed in an annular shape along the outer peripheral edge of the lens body 20. The flange 22 has a first flange surface 24 and a second flange surface 26. The first flange surface 24 protrudes from the outer peripheral edge of the convex surface 16 toward the radial outer side of the compound lens 10, and the second flange surface 26 protrudes from the outer peripheral edge of the concave surface 18 toward the radial outer side of the compound lens 10. As an example, both the first flange surface 24 and the second flange surface 26 extend in a direction orthogonal to the optical axis direction of the compound lens 10. The concave surface 18 and the second flange surface 26 are formed by a mold 56 (refer to FIG. 5 ) described later. Figure 3 ) formed surface 28.

[0091] As an example, the second lens 14 is a plano-concave lens and has a plane 30 and a concave surface 32. The plane 30 is formed in a planar shape, and the concave surface 32 is formed in a concave shape. The concave surface 32 is a surface located on the opposite side of the plane 30 in the optical axis direction of the compound lens 10. The convex surface 16 of the first lens 12 is bonded to the concave surface 32. In addition, the second lens 14 has a sliding surface 34. The sliding surface 34 is formed by a rough surface with concave and convex. The sliding surface 34 protrudes from the outer peripheral edge of the concave surface 32 to the radial outer side of the compound lens 10. As an example, the sliding surface 34 extends in a direction orthogonal to the optical axis direction of the compound lens 10. A ridgeline 36 is formed between the concave surface 32 and the sliding surface 34. The ridgeline 36 is formed in a ring shape along the outer peripheral edge of the concave surface 32.

[0092] The first flange surface 24 is joined to the sliding surface 34. As an example, the first flange surface 24 is joined to the first region 34A on the concave surface 32 side of the sliding surface 34. The second region 34B of the sliding surface 34 excluding the first region 34A is used as, for example, a clamping end when the compound lens 10 is held by a holding device (not shown). That is, the portion of the compound lens 10 including the second region 34B is a held portion 38 held by the holding device.

[0093] In addition, Figure 1 In the example shown, a plano-concave lens is used as an example of the second lens 14, but the second lens 14 may be a biconcave lens having a concave surface instead of the plane 30. Furthermore, the second lens 14 may be a concave meniscus lens having a convex surface instead of the plane 30.

[0094] The compound lens 10 is an example of a "compound lens" according to the technology of the present invention. The first lens 12 is an example of a "first lens" according to the technology of the present invention. The second lens 14 is an example of a "second lens" according to the technology of the present invention. The convex surface 16 is an example of a "convex surface" according to the technology of the present invention. The concave surface 18 is an example of a "concave surface" according to the technology of the present invention. The first flange surface 24 is an example of a "first surface" according to the technology of the present invention. The sliding surface 34 is an example of a "second surface" according to the technology of the present invention. The second flange surface 26 is an example of a "third surface" according to the technology of the present invention.

[0095] (Dimensional relationship of compound lenses)

[0096] Next, the dimensional relationship of the compound lens 10 is described. As an example, Figure 2 As shown, in the following description, the length of the first flange surface 24 along the radial direction of the compound lens 10 is referred to as "length a", and the length of the sliding surface 34 along the radial direction of the compound lens 10 is referred to as "length b". In addition, the length from the first flange surface 24 to the second flange surface 26 along the optical axis direction of the compound lens 10 is referred to as "length c", and the surface roughness of the sliding surface 34 is referred to as "surface roughness Ra". The units of length a, length b, length c and surface roughness Ra are all "μm (micrometer)".

[0097] Furthermore, the maximum value of the thickness of the first lens 12 is referred to as "maximum thickness A", and the minimum value of the thickness of the first lens 12 is referred to as "minimum thickness B". The units of the maximum thickness A and the minimum thickness are both "mm (millimeter)". The thickness of the first lens 12 is defined by the length from the convex surface 16 to the concave surface 18 along the optical axis direction of the compound lens 10. As an example, the maximum thickness A corresponds to the thickness of the first lens 12 at the center of the first lens 12. And, as an example, the minimum thickness B corresponds to the thickness of the end portion of the flange 22 side of the lens body 20.

[0098] (Applicable to compound lens size)

[0099] Next, an example of dimensions applicable to the compound lens 10 is described. The difference between the thickness of the first lens 12 at the center of the convex surface 16 and the thickness of the first lens 12 at the first flange surface 24 (i.e., the thickness of the flange 22) is greater than 0.01 mm and less than 1 mm. The effective diameter of the convex surface 16 is greater than 3 mm and less than 50 mm. The outer diameter of the second lens 14 is greater than 4 mm and less than 110 mm. The thickness of the second lens 14 at the center of the concave surface 32 is greater than 0.5 mm and less than 10 mm. The effective diameter of the concave surface 32 is greater than 3 mm and less than 50 mm. The radius of curvature of the concave surface 32 is greater than 5 mm and less than 300 mm. The radius of curvature of the convex surface 16 is the same as the radius of curvature of the concave surface 32. In addition, the above dimensions are only examples, and the dimensions of the compound lens 10 may also be dimensions other than those mentioned above.

[0100] (Applicable to materials of the first and second lenses)

[0101] Next, an example of a material suitable for the first lens 12 and the second lens 14 is described. As an example, the first lens 12 is formed of a photocurable and thermosetting resin. Specifically, the first lens 12 is formed of a mixed resin of a photocurable resin and a thermosetting resin. As the photocurable resin forming the first lens 12, for example, the curable resin described in the pamphlet of International Publication No. 2022 / 039143 can be cited.

[0102] For example, the linear expansion coefficient of the first lens 12 is 6×10 -5 / °C, the elastic modulus of the first lens 12 is 2.5×10 9 Pa. As the glass forming the second lens 14, for example, S-FPL5 manufactured by OHARA INC. can be cited. For example, the linear expansion coefficient of the second lens 14 is 0.77×10 -5 / °C, the elastic modulus of the second lens 14 is 106.7×10 9 Pa.

[0103] (Method for manufacturing compound lens)

[0104] Next, an example of a method for manufacturing the compound lens 10 is described. Figure 3In the example shown, as the resin for forming the first lens 12, a resin 50 is used. The resin 50 is a photothermosetting resin. In the manufacturing method of the composite lens 10, first, the resin 50 in an uncured state is supplied to the concave surface 32 by the supply device 52. Next, in a state where the second lens 14 is held by the clamp 54, the resin 50 is pressed toward the second lens 14 side from the side opposite to the second lens 14 by the mold 56. A molding surface 58 having a shape that is an inverted shape of the molding surface 28 is formed in the mold 56. The molding surface 28 is formed in the resin 50 by the molding surface 58.

[0105] Next, light 62 is output from a light source 60 disposed on the side opposite to the resin 50 and the mold 56. The light 62 is light in a wavelength region that cures the resin 50. The light 62 output from the light source 60 passes through the second lens 14 and is irradiated onto the resin 50. By irradiating the resin 50 with the light 62, the photocurable resin contained in the resin 50 undergoes a curing reaction, and the resin 50 becomes a semi-cured state. Next, the mold 56 is heated by the heating device 64. The heat of the mold 56 heated by the heating device 64 is transferred to the resin 50, thereby heating the resin 50. In addition, the thermosetting resin contained in the resin 50 undergoes a curing reaction, and the resin 50 becomes a cured state. By curing the resin 50, the first lens 12 integrated with the second lens 14 is formed. The composite lens 10 having the first lens 12 and the second lens 14 is manufactured by the above method.

[0106] (Issues of Compound Lenses)

[0107] Next, the subject of the compound lens 10 is described. As an example, Figure 4 As shown in FIG. 1 , a concavo-convex shape is formed on the sliding surface 34. The concavo-convex shape formed on the sliding surface 34 meshes with the concavo-convex shape formed on the first flange surface 24. The diameter φ of the concave portion 40 included in the concavo-convex shape formed on the sliding surface 34 is about 50 μm. Figure 4 In the figure, the sizes of the concavo-convex shapes are exaggerated to facilitate understanding of the concavo-convex shapes.

[0108] As an example, the sliding surface 34 is formed by grinding. In the region on the boundary side with the concave surface 32 in the sliding surface 34 (hereinafter referred to as "boundary region 34C"), a plurality of microcracks 42 are generated along with the grinding. The microcracks 42 are generated by stress concentration in the boundary region 34C when the sliding surface 34 is ground. The stress is concentrated in the boundary region 34C because the boundary region 34C is connected to the ridgeline 36. The region adjacent to the boundary region 34C (hereinafter referred to as "adjacent region 34D") is relaxed by being away from the ridgeline 36, and therefore is an area that does not include the microcracks 42.

[0109] exist Figure 4In the example shown, the first flange surface 24 is joined to the sliding surface 34 only in the boundary region 34C. That is, the first flange surface 24 is included in the range of the length of the boundary region 34C. Figure 4 In the example shown, when the first lens 12 is deformed radially inward (i.e., arrow IN side) of the composite lens 10 due to curing shrinkage and / or thermal shrinkage, the sliding surface 34 is stretched by the first flange surface 24, and cracks 44 may be generated from the sliding surface 34 toward the inside of the second lens 14 starting from the microcracks 42. When the number and / or size of the cracks 44 exceed the allowable range, the second lens 14 may be destroyed by the physical force generated by the deformation of the first lens 12.

[0110] Here, in order to suppress the force of pulling the sliding surface 34 by the first flange surface 24 , it is conceivable to reduce the value of the surface roughness Ra. However, when the value of the surface roughness Ra is reduced, light is reflected on the sliding surface 34 and optical defects may occur in the composite lens 10 .

[0111] Therefore, the compound lens 10 is required to prevent optical defects caused by reflection of light on the sliding surface 34 and damage to the second lens 14 caused by physical force caused by deformation of the first lens 12. In addition, the first lens 12 formed of resin is required to ensure quality related to optical performance.

[0112] (Examples and Comparative Examples of Compound Lenses)

[0113] Next, referring to Table 1, an example of making the length a, length c and surface roughness Ra different is described with respect to the embodiment and comparative example of the compound lens 10. As an example, the evaluation items of the embodiment and comparative example include "occurrence of cracks", "optical characteristics" and "gripability".

[0114] Regarding the "generation of cracks", the case where the cracks 44 are generated starting from the micro cracks 42 existing in the boundary area 34C of the sliding surface 34 is evaluated as "excellent", "good" or "unqualified". "Generation of cracks" is "excellent" which means that the cracks 44 are not generated and the second lens 14 can be prevented from being destroyed. "Generation of cracks" is "good" which means that although the cracks 44 are generated, the number and / or size of the cracks 44 are within the allowable range, and the second lens 14 can be prevented from being destroyed. "Generation of cracks" is "unqualified" which means that the number and / or size of the cracks 44 are outside the allowable range and the second lens 14 is destroyed.

[0115] Regarding the "optical characteristics", the optical characteristics of the compound lens 10 are evaluated as "excellent", "good" or "unqualified". The closer the sliding surface 34 is to a plane, the greater the intensity of the light reflected on the sliding surface 34, which affects the optical characteristics of the compound lens 10. "Excellent" for "optical characteristics" means that the optical characteristics of the compound lens 10 are not affected, and optical defects can be prevented from occurring in the compound lens 10. "Good" for "optical characteristics" means that although the optical characteristics of the compound lens 10 are affected, the intensity of the light reflected on the sliding surface 34 is within the allowable range, and optical defects can be prevented from occurring in the compound lens 10. "Unqualified" for "optical characteristics" means that the intensity of the light reflected on the sliding surface 34 is outside the allowable range, and optical defects occur in the compound lens 10.

[0116] Regarding "holdability", the operability when the holding portion 38 is held by the holding device is evaluated as "excellent", "good" or "unqualified". As described above, the compound lens 10 has a holding portion 38, and the conveying operation and the assembly operation are performed in a state where the holding portion 38 is held by the holding device. "Excellent" for "holdability" means that the length of the holding portion 38 is longer than the minimum length required when the holding portion 38 is held by the holding device, thereby ensuring the stability of the compound lens 10 when the holding portion 38 is held by the holding device. "Good" for "holdability" means that the length of the holding portion 38 is set to the minimum length required when the holding portion 38 is held by the holding device, thereby ensuring the stability of the compound lens 10 when the holding portion 38 is held by the holding device. "Unacceptable" for "graspability" means that the length of the grasped portion 38 is shorter than the minimum length required for the grasped portion 38 to be grasped by the grasping device, and the grasped portion 38 cannot be grasped by the grasping device.

[0117] [Table 1]

[0118] a[μm] c[μm] Ra[μm] Crack generation Optical properties Being controlled 1 Example 150 150 3 excellent excellent excellent 2 Example 150 150 20 good excellent excellent 3 Comparative Example 150 150 21 Failure excellent excellent 4 Comparative Example 150 150 22 Failure excellent excellent 5 Comparative Example 150 150 25 Failure excellent excellent 6 Comparative Example 150 150 0.4 excellent Failure excellent 7 Example 150 150 0.5 excellent good excellent 8 Example 100 150 3 good excellent excellent 9 Comparative Example 50 150 3 Failure excellent excellent 10 Example 150 200 3 excellent excellent excellent 11 Example 150 300 3 good excellent excellent 12 Comparative Example 150 350 3 Failure excellent excellent 13 Example 500 150 3 excellent excellent excellent 14 Example 800 150 3 excellent excellent excellent 15 Example 1000 150 3 excellent excellent good 16 Comparative Example 1100 150 3 excellent excellent Failure 17 Example 150 100 3 excellent excellent excellent 18 Example 150 50 3 excellent excellent excellent 19 Example 150 10 3 excellent good excellent 20 Comparative Example 150 9 3 excellent Failure excellent

[0119] According to the examples and comparative examples shown in Table 1, the compound lens 10 preferably satisfies the following conditional expressions (1), (2), and (3).

[0120] a<b (1)

[0121] 100μm≤a (2)

[0122] 0.5μm≤Ra≤20μm (3)

[0123] When the length a in the conditional expression (2) is less than 100 μm, the second lens 14 is destroyed due to the generation of the crack 44. When the length a in the conditional expression (2) is 100 μm or more, the second lens 14 can be prevented from being destroyed by suppressing the generation of the crack 44. When the length a is 100 μm or more, the factor for suppressing the generation of the crack 44 starting from the microcrack 42 existing in the boundary region 34C of the sliding surface 34 is presumably because the first flange surface 24 is bonded to the adjacent region 34D (i.e., the region not including the microcrack 42) adjacent to the boundary region 34C in addition to the boundary region 34C including the microcrack 42.

[0124] When the surface roughness Ra in the conditional expression (3) is less than 0.5 μm, the optical characteristics of the compound lens 10 are affected by the light reflected on the sliding surface 34, thereby causing optical defects in the compound lens 10. When the surface roughness Ra in the conditional expression (3) is 0.5 μm or more, the optical characteristics of the compound lens 10 are affected by the light reflected on the sliding surface 34, thereby preventing the occurrence of optical defects in the compound lens 10. When the surface roughness Ra in the conditional expression (3) exceeds 20 μm, the crack 44 is generated starting from the microcrack 42 existing in the boundary region 34C of the sliding surface 34, thereby destroying the second lens 14. When the surface roughness Ra in the conditional expression (3) is 20 μm or less, the crack 44 is suppressed from being generated starting from the microcrack 42 existing in the boundary region 34C of the sliding surface 34, thereby preventing the second lens 14 from being destroyed. When the surface roughness Ra is less than 20 μm, the factor for suppressing the generation of cracks 44 starting from microcracks 42 existing in the boundary area 34C of the sliding surface 34 is presumed to be as follows: the force of the engagement between the concavo-convex shape of the sliding surface 34 and the concavo-convex shape of the first flange surface 24 is suppressed, thereby suppressing the physical force generated in the boundary area 34C of the sliding surface 34 accompanying the deformation of the first lens 12.

[0125] In addition, regarding the destruction of the second lens 14, the influence caused by the difference in linear expansion coefficient between glass and resin is smaller than the influence caused by the elastic modulus of the resin. Moreover, the lower the elastic modulus of the resin, the less likely the crack 44 is to occur. However, as a result of in-depth research conducted by the inventors, it was experimentally confirmed that the influence caused by the length a, the length c and the surface roughness Ra is greater than the influence caused by the elastic modulus of the resin.

[0126] Furthermore, according to the examples and comparative examples shown in Table 1, the compound lens 10 preferably satisfies the following conditional expression (4).

[0127] ba≥700μm (4)

[0128] In addition, in the embodiment and comparative example of the compound lens 10, the length b is set to 1700 μm. In Table 1, the corresponding value of conditional expression (4) is 700 μm or more, which is equivalent to the length a being 1000 μm or less. When the corresponding value of conditional expression (4) is less than 700 μm, the holding device interferes with the flange 22, and the holding device cannot hold the held portion 38, making it difficult to assemble the compound lens 10 to the imaging lens. When the corresponding value of conditional expression (4) is 700 μm or more, when the holding device holds the held portion 38, the holding device is prevented from interfering with the flange 22, and the stability of the compound lens 10 is ensured. Thus, the operability when assembling the compound lens 10 to the imaging lens is ensured.

[0129] Furthermore, the compound lens 10 more preferably satisfies the following conditional expression (5).

[0130] 5≤a / Ra (5)

[0131] When the corresponding value of the conditional expression (5) is 5 or more, it is possible to more effectively prevent the occurrence of optical defects due to reflection of light on the second surface and the destruction of the second lens 14 due to the physical force caused by the deformation of the first lens 12 .

[0132] Furthermore, the compound lens 10 more preferably satisfies the following conditional expression (6).

[0133] 10μm≤c≤300μm (6)

[0134] When the length c in the conditional expression (6) is less than 10 μm, when the resin 50 is supplied to the concave surface 32 by the supply device 52, the deviation of the amount of the resin 50 cannot be allowed, and the length a is unstable. When the length c in the conditional expression (6) is greater than 10 μm, when the resin 50 is supplied to the concave surface 32 by the supply device 52, the deviation of the amount of the resin 50 can be allowed, and the length a is stable. In addition, when the length c in the conditional expression (6) exceeds 300 μm, the second lens 14 is destroyed due to the generation of the crack 44. When the length c in the conditional expression (6) is less than 300 μm, the second lens 14 can be prevented from being destroyed by suppressing the generation of the crack 44.

[0135] Furthermore, the compound lens 10 more preferably satisfies the following conditional expression (7).

[0136] 100μm≤c≤300μm (7)

[0137] When the length c in conditional expression (7) is 100 μm or more, the effect obtained when the length c is 10 μm or more is further improved. In addition, when the length c in conditional expression (7) is 100 μm or more, the first lens 12 is easier to manufacture than when the length c is less than 100 μm.

[0138] Furthermore, the compound lens 10 more preferably satisfies the following conditional expression (8).

[0139] 1μm≤Ra≤4μm (8)

[0140] When the surface roughness Ra in conditional formula (8) is 1 μm or more, the effect obtained when the surface roughness Ra is 0.5 μm or more is further improved. When the surface roughness Ra in conditional formula (8) is 4 μm or more, the effect obtained when the surface roughness Ra is 20 μm or less is further improved.

[0141] Next, referring to Table 2, an example in which the maximum thickness A and the minimum thickness B are different for the embodiments and comparative examples of the first lens 12 is described. In Table 2, as parameters, in addition to the maximum thickness A and the minimum thickness B, a thickness deviation rate A / B indicating the ratio of the maximum thickness A to the minimum thickness B is also shown. As an example, as an evaluation item for the embodiments and comparative examples, "quality of the first lens" can be cited.

[0142] Regarding the "quality of the first lens", as an example, the quality of the molded surface 28 molded by the mold 56 is evaluated as "excellent", "good" or "unsatisfactory". "Excellent" for the "quality of the first lens" means that the quality related to the optical performance of the first lens 12 can be ensured by preventing the generation of bubbles and poor transfer on the molded surface 28 when the resin 50 is molded by the mold 56. The poor transfer is caused by the insufficient pressing force based on the mold 56 relative to the portion corresponding to the maximum thickness A in the first lens 12 (hereinafter referred to as the "maximum thickness portion"). "Good" for the "quality of the first lens" means that although bubbles and / or poor transfer are generated on the molded surface 28, the number and / or size of the areas where bubbles and / or poor transfer are generated are within the allowable range, thereby ensuring the quality related to the optical performance of the first lens 12. "Unsatisfactory" for the "quality of the first lens" means that the number of areas where bubbles and / or poor transfer are generated is outside the allowable range, thereby the quality related to the optical performance of the first lens 12 is insufficient.

[0143] [Table 2]

[0144] A[mm] B[mm] A / B The quality of the first lens 1 Example 1 0.2 5 excellent 2 Example 1.8 0.2 9 excellent 3 Example 2.9 0.4 7.25 excellent 4 Example 3 0.4 7.5 good 5 Comparative Example 3.1 0.4 7.75 Failure 6 Example 0.5 0.1 5 excellent 7 Example 0.3 0.1 3 excellent 8 Example 0.1 0.03 3.3 good 9 Comparative Example 0.09 0.03 3 Failure 10 Example 0.3 0.02 1.5 good 11 Comparative Example 0.09 0.01 9 Failure 12 Example 1 0.1 10 good 13 Comparative Example 1 0.09 11 Failure

[0145] According to the examples and comparative examples shown in Table 2, the first lens 12 preferably satisfies the following conditional expressions (9) and (10).

[0146] A / B≤10(9)

[0147] A≤3mm (10)

[0148] When the thickness deviation ratio A / B in the conditional expression (9) is greater than 10, bubbles are generated on the molded surface 28, and the quality of the optical performance of the first lens 12 is insufficient. When the thickness deviation ratio A / B in the conditional expression (9) is 10 or less, the quality of the optical performance of the first lens 12 is ensured by suppressing the generation of bubbles and poor transfer on the molded surface 28. When the maximum thickness A in the conditional expression (10) is thicker than 3 mm, bubbles are generated on the molded surface 28, and the quality of the optical performance of the first lens 12 is insufficient. When the maximum thickness A in the conditional expression (10) is 3 mm or less, the quality of the optical performance of the first lens 12 is ensured by suppressing the generation of bubbles and poor transfer on the molded surface 28.

[0149] Furthermore, according to the examples and comparative examples shown in Table 2, the first lens 12 preferably satisfies the following conditional expressions (11) and (12).

[0150] A≥0.1mm (11)

[0151] B≥0.02mm (12)

[0152] When the maximum thickness A in the conditional expression (11) is less than 0.1 mm, poor transfer occurs on the molded surface 28, and the quality related to the optical performance of the first lens 12 is insufficient. When the maximum thickness A in the conditional expression (11) is 0.1 mm or more, the quality related to the optical performance of the first lens 12 is ensured by suppressing the generation of bubbles and poor transfer on the molded surface 28. When the minimum thickness B in the conditional expression (12) is less than 0.02 mm, bubbles occur on the molded surface 28, and the quality related to the optical performance of the first lens 12 is insufficient. When the minimum thickness B in the conditional expression (12) is 0.02 mm or more, the quality related to the optical performance of the first lens 12 is ensured by suppressing the generation of bubbles and poor transfer on the molded surface 28.

[0153] (Micro hardness test of resin)

[0154] Next, an example of a micro-hardness test performed on a resin suitable for the first lens 12 is described. In the micro-hardness test, for example, a dynamic ultra-micro hardness tester DUH-211S manufactured by SHIMADZU CORPORATION is used. As the indenter, a Berkovich type indenter is used. In addition, other measuring devices similar to the dynamic ultra-micro hardness tester DUH-211S manufactured by SHIMADZU CORPORATION may also be used in the micro-hardness test.

[0155] In the microhardness test, as an example of a test piece of a resin in a cured state, a flat plate-shaped test piece with a diameter of 7.4 mm and a thickness of 1.3 mm is used. The thickness of the test piece is generally set to the plastic deformation amount x (reference Figure 5 ) is about 10 times of the thickness of the resin. Therefore, the thickness of the resin does not need to be 1.3mm. For example, if the amount of plastic deformation is 5μm, the thickness of the resin can be 50μm, 100μm or 200μm, etc. Furthermore, if the thickness condition is met, the resin used for the micro hardness test does not need to be flat. The test piece is arranged in an environment where the ambient temperature is set to 25°C. As an example, the test piece is placed on a hot plate set to 25°C. 25°C is a temperature that simulates room temperature. A constant temperature bath is used instead of a hot plate, and the temperature of the constant temperature bath can be set to 25°C. The test piece is pressed in by a pressing head at a load speed of 200mN / 10sec at an ambient temperature of 25°C.

[0156] As an example, in Figure 5 The load displacement curve when the indenter is pressed into the test piece in the micro hardness test is shown in . As an example, in the micro hardness test, the state where the maximum load is applied and the state after unloading are maintained for 5 seconds, respectively, so that the test piece creeps.

[0157] Table 3 shows the relationship between the amount of plastic deformation x obtained by the micro-hardness test and the evaluation items related to the composite lens 10. The unit of the amount of plastic deformation x is "μm (micrometer)". In the micro-hardness test, the amount of plastic deformation x when the resin material is different is measured. The amount of plastic deformation x is defined as the amount of deformation remaining after the test piece creeps by keeping the unloaded state for 5 seconds. The number of tests for each material is 10 times, and the amount of plastic deformation x is calculated by the average value of the values ​​obtained in each test. As an example, as evaluation items related to the composite lens 10, "quality of coating", "environmental resistance" and "adsorption resistance" can be cited.

[0158] Regarding the "quality of the coating", the quality of the coating of the first lens 12 when AR (Anti Reflection) coating is applied to the first lens 12 is evaluated as "excellent", "good" or "unqualified". AR coating refers to a multilayer film for anti-reflection applied on the concave surface 18 of the first lens 12. AR coating is formed, for example, by vapor deposition. "Excellent" for the "quality of the coating" means that the concave surface 18 applied with AR coating is not deformed, and the quality of the coating can be ensured. "Good" for the "quality of the coating" means that although the concave surface 18 is deformed, the deformation amount of the concave surface 18 is within the allowable range, and the quality of the coating can be ensured. "Unqualified" for the "quality of the coating" means that the deformation amount of the concave surface 18 is outside the allowable range, and the quality of the coating is insufficient.

[0159] Regarding "environmental resistance", the durability of the compound lens 10 when placed in a low-temperature environment is evaluated as "excellent", "good" or "unqualified". "Excellent" for "environmental resistance" means that even when the compound lens 10 is placed in a low-temperature environment, cracks 44 will not be generated, and the second lens 14 can be prevented from being damaged. "Good" for "environmental resistance" means that when the compound lens 10 is placed in a low-temperature environment, although cracks 44 will be generated, the number and / or size of the cracks 44 are within the allowable range, and the second lens 14 can be prevented from being damaged. "Unqualified" for "environmental resistance" means that the number and / or size of the cracks 44 generated when the compound lens 10 is placed in a low-temperature environment are outside the allowable range, and the second lens 14 is damaged.

[0160] Regarding the "adsorption resistance", the scratches generated on the concave surface 18 of the first lens 12 when the concave surface 18 of the first lens 12 is adsorbed by an adsorption pad or the like in order to transport the composite lens 10 are evaluated as "excellent", "good" or "unacceptable". "Excellent" for "adsorption resistance" means that even when the concave surface 18 of the first lens 12 is adsorbed by an adsorption pad or the like, the concave surface 18 does not deform, and the quality of the first lens 12 can be ensured. "Good" for "adsorption resistance" means that when the concave surface 18 of the first lens 12 is adsorbed by an adsorption pad or the like, although the concave surface 18 is deformed, the deformation amount of the concave surface 18 is within the allowable range, and the quality of the first lens 12 can be ensured. "Unacceptable" for "adsorption resistance" means that when the concave surface 18 of the first lens 12 is adsorbed by an adsorption pad or the like, the deformation amount of the concave surface 18 is outside the allowable range, and the quality of the first lens 12 is insufficient.

[0161] [Table 3]

[0162] x[μm] Coating quality Environmental resistance Adsorption resistance 1 Example 1 excellent good excellent 2 Example 3 excellent excellent excellent 3 Example 4 good excellent good 4 Comparative Example 4.1 good excellent Failure 5 Comparative Example 4.2 good excellent Failure 6 Comparative Example 4.5 Failure excellent Failure 7 Comparative Example 5 Failure excellent Failure 8 Comparative Example 6 Failure excellent Failure 9 Comparative Example 0.9 excellent Failure excellent 10 Comparative Example 0.8 excellent Failure excellent 11 Comparative Example 0.5 excellent Failure excellent

[0163] According to the results of the microhardness test shown in Table 3, the resin preferably satisfies the following conditional formula (13).

[0164] 1.0μm≤x≤4.0μm (13)

[0165] When the amount of plastic deformation x in the conditional expression (13) is less than 1.0 μm, cracks 44 are generated, thereby destroying the second lens 14. When the amount of plastic deformation x in the conditional expression (13) is 1.0 μm or more, by suppressing the generation of cracks 44, it is possible to prevent the second lens 14 from being destroyed. When the amount of plastic deformation x in the conditional expression (13) exceeds 4.0 μm, when the concave surface 18 of the first lens 12 is adsorbed by an adsorption pad or the like, the concave surface 18 is deformed, thereby the quality of the first lens 12 is insufficient. When the amount of plastic deformation x in the conditional expression (13) is 4.5 μm or more, when AR coating is applied to the first lens 12, the concave surface 18 is deformed, thereby the quality of the first lens 12 is insufficient. When the plastic deformation amount x in conditional expression (13) is 4.0 μm or less, the concave surface 18 is prevented from being deformed even when the concave surface 18 of the first lens 12 is adsorbed by an adsorption pad or the like, and the concave surface 18 is prevented from being deformed even when AR coating is applied to the first lens 12. Thus, the quality of the first lens can be ensured.

[0166] In addition, the hardness of the resin at 25°C is preferably not less than 186 MPa and not more than 196 MPa. When the hardness of the resin at 25°C is less than 186 MPa, when the concave surface 18 of the first lens 12 is adsorbed by an adsorption pad or the like, scratches are generated on the concave surface 18. When the hardness of the resin at 25°C is not less than 186 MPa, scratches can be prevented from being generated on the concave surface 18 even when the concave surface 18 of the first lens 12 is adsorbed by an adsorption pad or the like. When the hardness of the resin at 25°C exceeds 196 MPa, the second lens 14 is destroyed by the physical force generated by the deformation of the first lens 12 in a low temperature environment or the like. When the hardness of the resin at 25°C is not more than 196 MPa, the second lens 14 can be prevented from being destroyed even in a low temperature environment or the like.

[0167] Furthermore, the hardness of the resin at 75° C. is preferably 149 MPa or more and 164 MPa or less. 75° C. is a temperature when AR coating or the like is applied to the concave surface 18 of the first lens 12. When the hardness of the resin at 75° C. is less than 149 MPa, the concave surface 18 is deformed when AR coating is applied to the first lens 12. When the hardness of the resin at 75° C. is 149 MPa or more, the concave surface 18 can be prevented from being deformed even when AR coating is applied to the first lens 12. When the hardness of the resin at 75° C. exceeds 164 MPa, when AR coating or the like is applied to the concave surface 18 of the first lens 12, the second lens 14 is broken due to the physical force generated by the deformation of the first lens 12. When the hardness of the resin at 75° C. is 164 MPa or less, even when AR coating or the like is applied to the concave surface 18 of the first lens 12, the second lens 14 is prevented from being broken due to the physical force generated by the deformation of the first lens 12.

[0168] Furthermore, the elastic recovery rate of the resin at 75°C is preferably not less than 59% and not more than 63%. When the elastic recovery rate of the resin at 75°C is less than 59%, when the concave surface 18 of the first lens 12 is adsorbed by an adsorption pad or the like, scratches are generated on the concave surface 18. When the elastic recovery rate of the resin at 75°C is not less than 59%, scratches can be prevented from being generated on the concave surface 18 even when the concave surface 18 of the first lens 12 is adsorbed by an adsorption pad or the like. When the elastic recovery rate of the resin at 75°C exceeds 63%, cracks 44 are generated, thereby destroying the second lens 14. When the elastic recovery rate of the resin at 75°C is not more than 63%, by suppressing the generation of cracks 44, destruction of the second lens 14 can be prevented.

[0169] Furthermore, the indentation modulus of the resin at 25°C is preferably greater than or equal to 3.5 GPa and less than or equal to 3.6 GPa. When the indentation modulus of the resin at 25°C is less than 3.5 GPa, the concave surface 18 is deformed when AR coating is applied to the first lens 12. When the indentation modulus of the resin at 25°C is greater than or equal to 3.5 GPa, deformation of the concave surface 18 can be prevented even when AR coating is applied to the first lens 12. When the indentation modulus of the resin at 25°C exceeds 3.6 GPa, the second lens 14 is destroyed by the physical force generated by the deformation of the first lens 12 in a low temperature environment, etc. When the indentation modulus of the resin at 25°C is less than or equal to 3.6 GPa, destruction of the second lens 14 can be prevented even in a low temperature environment, etc.

[0170] Furthermore, the indentation modulus of elasticity of the resin at 75° C. is preferably 2.2 GPa or more and 2.4 GPa or less. When the indentation modulus of elasticity of the resin at 75° C. exceeds 2.4 GPa, the second lens 14 is destroyed by the physical force generated by the deformation of the first lens 12 caused by thermal expansion. When the indentation modulus of elasticity of the resin at 75° C. is 2.4 GPa or less, even when the first lens 12 is deformed by thermal expansion, the second lens 14 can be prevented from being destroyed.

[0171] (Structure of Imaging Lens Including Compound Lens 10)

[0172] Next, an example of an imaging lens including the compound lens 10 is described. Figure 6 The state in which the imaging lens involved in one embodiment of the present invention is focused on an infinitely distant object is shown in FIG. The imaging lens is an example of an "optical system" involved in the technology of the present invention. In addition, in this specification, an object at an infinite distance is referred to as an infinitely distant object, and an object at the closest distance is referred to as a closest object. Figure 6 In the example shown, the left side is the object side and the right side is the image side.

[0173] As an example, Figure 6 , an example is shown in which an imaging lens is assumed to be applied to an imaging device and a parallel flat plate-shaped optical component PP is arranged between the imaging lens and the image plane Sim. The optical component PP is a component that is assumed to be various filters and / or cover glass, etc. The various filters are low-pass filters, infrared cut-off filters, and / or filters that cut off specific wavelength regions, etc. The optical component PP is a component that does not have optical power. It is also possible to omit the optical component PP and constitute an imaging lens.

[0174] The imaging lens has a front group GF, an aperture stop St, and a rear group GR. The front group GF, the aperture stop St, and the rear group GR are arranged in this order from the object side to the image side along the optical axis Z. According to this structure, it is advantageous to maintain miniaturization and lightness and suppress various aberrations.

[0175] As an example, the front group GF and the rear group GR of the imaging lens are configured as follows. The front group GF includes the first lens group G1. The first lens group G1 includes nine lenses, namely, lenses L11 to L19, in order from the object side to the image side. The rear group GR includes the second lens group G2 and the third lens group G3 in order from the object side to the image side. The second lens group G2 includes eight lenses, namely, lenses L21 to L28. The third lens group G3 includes one lens, namely, lens L31.

[0176] exist Figure 6 In the example shown, when focusing, the first lens group G1 and the third lens group G3 are fixed relative to the image plane Sim, and the second lens group as a whole moves along the optical axis Z in an integrated manner. The "moving in an integrated manner" mentioned here means moving the same amount in the same direction at the same time. In this specification, the group moving along the optical axis Z when focusing is referred to as the focusing group. Focusing is performed by moving the focusing group. Figure 6 The leftward arrow below the second lens group G2 shows that when focusing from an object at infinity to a nearest object, the second lens group G2 is a focusing group that moves toward the object side.

[0177] In addition, in this specification, a "lens group" is a component of an imaging lens and is a part including at least one lens divided by an air gap that changes when focusing. When focusing, each lens group is moved or fixed as a unit, and the gap between lenses in each lens group does not change. That is, in this specification, a group whose gap with adjacent groups changes when focusing and whose overall gap between adjacent lenses does not change within itself is set as one lens group.

[0178] The rear group GR of the imaging lens includes at least one Lp lens Lp made of resin and having positive refractive power bonded to the lens. By arranging the Lp lens Lp made of resin as described above in the rear group GR, it is possible to achieve a lightweight lens and to easily correct axial chromatic aberration and lateral chromatic aberration in a balanced manner. Figure 6 In the example shown, lens L24 corresponds to Lp lens Lp. Figure 6 The lens L24 of the example shown is cemented to the lens L23 and the lens L25. The image side surface of the Lp lens corresponds to a convex surface, and the object side surface of the Lp lens corresponds to a concave surface.

[0179] The Lp lens Lp preferably satisfies the following conditional expression (14). Here, the center thickness of the Lp lens Lp is set to d, the curvature radius of the surface on the object side of the Lp lens Lp is set to Rf, and the curvature radius of the surface on the image side of the Lp lens Lp is set to Rr. As an example, Figure 7 Shown in Figure 6 An enlarged view of a portion of the Lp lens Lp of the imaging lens shown. The Lp lens Lp satisfying conditional formula (14) has a shape in which d is small and Rf and Rr are close. By making the corresponding value of conditional formula (14) not be less than the lower limit, the optical focal length of the Lp lens Lp can be enhanced, thereby obtaining a higher chromatic aberration correction effect. By making the corresponding value of conditional formula (14) not be more than the upper limit, the optical focal length and thickness of the Lp lens Lp can be appropriately set, thereby easily suppressing aberration changes when the refractive index of the Lp lens Lp changes due to environmental changes such as temperature. In order to obtain better characteristics, the Lp lens Lp preferably satisfies the following conditional formula (14-1), further preferably satisfies the following conditional formula (14-2), and further preferably satisfies the following conditional formula (14-3).

[0180] 0<d×(1 / Rf-1 / Rr)<0.05 (14)

[0181] 0.0001<d×(1 / Rf-1 / Rr)<0.025 (14-1)

[0182] 0.0005<d×(1 / Rf-1 / Rr)<0.015 (14-2)

[0183] 0.0013<d×(1 / Rf-1 / Rr)<0.009 (14-3)

[0184] The imaging lens preferably satisfies the following conditional expression (15). Here, the sum of the distance on the optical axis from the lens surface closest to the object side of the front group GF to the lens surface closest to the image side of the rear group GR in the state of focusing on an infinitely distant object and the air-converted distance on the optical axis from the lens surface closest to the image side of the rear group GR to the image plane Sim is set to TL, and the focal length of the Lp lens Lp is set to fp. In addition, regarding the calculation of fp, the medium on the object side and the image side of the Lp lens Lp is performed as air. By making the corresponding value of the conditional expression (15) not be less than the lower limit, the chromatic aberration correction effect of the Lp lens Lp can be improved. By making the corresponding value of the conditional expression (15) not be more than the upper limit, the aberration change when the refractive index of the Lp lens Lp changes due to environmental changes such as temperature can be suppressed. In order to obtain better characteristics, the imaging lens preferably satisfies the following conditional expression (15-1), and further preferably satisfies the following conditional expression (15-2).

[0185] 0.1<TL / fp<1.2 (15)

[0186] 0.15<TL / fp<0.95 (15-1)

[0187] 0.25<TL / fp<0.61 (15-2)

[0188] The imaging lens preferably satisfies the following conditional expression (16). Here, the height of the principal ray 3p of the maximum half viewing angle ωm on the object side surface of the Lp lens Lp in the state of focusing on the infinitely distant object from the optical axis Z is set to Hpp. And, the height of the on-axis marginal ray 2m on the object side surface of the Lp lens Lp in the state of focusing on the infinitely distant object from the optical axis Z is set to Hpm. As an example, Figure 8 Shown in Figure 6 The height Hpp and the height Hpm in the imaging lens are shown. Figure 8 In the figure, the image plane Sim is magnified together with each light ray from the lens L24 corresponding to the Lp lens Lp. By making the corresponding value of the conditional expression (16) not less than the lower limit, it is beneficial to correct the magnification chromatic aberration. By making the corresponding value of the conditional expression (16) not more than the upper limit, it is beneficial to correct the axial chromatic aberration. In order to obtain better characteristics, the imaging lens preferably satisfies the following conditional expression (16-1), and further preferably satisfies the following conditional expression (16-2).

[0189] 0.2<Hpp / Hpm<1.1 (16)

[0190] 0.31<Hpp / Hpm<0.9 (16-1)

[0191] 0.5<Hpp / Hpm<0.72 (16-2)

[0192] The imaging lens preferably satisfies the following conditional expression (17). Here, when the point on the optical axis at the position of the aperture stop St is set as the object point in the state of focusing on an infinitely distant object, the distance on the optical axis from the image point formed by the optical system from the lens surface adjacent to the image side of the aperture stop St to the surface on the image side of the Lp lens Lp to the surface on the image side of the Lp lens Lp is set to De. As an example, Figure 7 Shown in Figure 6 The distance De in the imaging lens shown. Here, the medium closer to the image side than the image side surface of the Lp lens Lp is calculated as air De. On the optical axis, if the image point is located at a position closer to the object side than the image side surface of the Lp lens Lp, the sign of De is set to negative, and if the image point is located at a position closer to the image side than the image side surface of the Lp lens Lp, the sign of De is set to positive. By making the corresponding value of the conditional formula (17) not be below the lower limit, it is beneficial to correct the chromatic aberration of magnification. By making the corresponding value of the conditional formula (17) not be above the upper limit, it is beneficial to miniaturization. In order to obtain better characteristics, the imaging lens preferably satisfies the following conditional formula (17-1), and further preferably satisfies the following conditional formula (17-2).

[0193] -0.9<(De-Rr) / (De+Rr)<0.9 (17)

[0194] -0.7<(De-Rr) / (De+Rr)<0.5 (17-1)

[0195] -0.56<(De-Rr) / (De+Rr)<0.16 (17-2)

[0196] When the focal length of the focus group moving along the optical axis Z during focusing is set to ffoc, the imaging lens preferably satisfies the following conditional formula (18). By making the corresponding value of the conditional formula (18) not be less than the lower limit, it is beneficial to suppress the change of chromatic aberration during focusing. By making the corresponding value of the conditional formula (18) not be more than the upper limit, it is possible to suppress the change of aberration when the refractive index of the Lp lens Lp changes due to environmental changes such as temperature. In order to obtain better characteristics, the imaging lens more preferably satisfies the following conditional formula (18-1), and further more preferably satisfies the following conditional formula (18-2).

[0197] 0.04<ffoc / fp<0.36 (18)

[0198] 0.065<ffoc / fp<0.28 (18-1)

[0199] 0.094<ffoc / fp<0.22 (18-2)

[0200] When the maximum viewing angle in the state of focusing on an object at infinity is set to ωm, when the imaging lens satisfies the following conditional expression (19), the rear group GR preferably includes an Lp lens Lp. The unit of the maximum viewing angle ωm is "° (degree)". By making the corresponding value of conditional expression (19) not less than the lower limit, good optical performance can be obtained.

[0201] ωm ≥ 45°(19)

[0202] On the other hand, when the imaging lens satisfies the following conditional expression (20), the front group GF preferably includes an Lp lens Lp. Good optical performance can also be obtained by making the corresponding value of the conditional expression (20) not exceed the lower limit.

[0203] ωm<45°(20)

[0204] The center thickness of the Lp lens Lp is set to A, the thickness of the composite lens in the optical axis direction at the maximum effective diameter height on both surfaces of the Lp lens Lp is set to B, the maximum image height is set to Y, the partial dispersion ratio between the g line and the F line of the Lp lens is set to θgF, and the Abbe number of the d line reference of the Lp lens is set to vd. When AθgF is expressed by conditional formula (21), the imaging lens preferably satisfies conditional formula (22). By making the corresponding value of conditional formula (22) not be less than the lower limit, a higher chromatic aberration correction effect can be obtained. By making the corresponding value of conditional formula (22) not be more than the upper limit, even when the temperature changes, the difference in deformation between the center and the peripheral part of the Lp lens Lp can be suppressed.

[0205] ΔθgF=θgF-(0.6438-0.001682×vd) (21)

[0206] 0.004<(|AB|AθgF) / Y<0.020(22)

[0207] Moreover, (|AB|ΔθgF) / Y is more preferably larger than 0.006 and smaller than 0.014. (|AB|ΔθgF) / Y is still more preferably larger than 0.008 and smaller than 0.012.

[0208] In the imaging lens, the compound lens 10 may be included in the front group GF, and the second lens 14 may be arranged on the object side relative to the first lens 12. In addition, in the imaging lens, the compound lens 10 may be included in the rear group GR, and the second lens 14 may be arranged on the image side relative to the first lens 12.

[0209] Next, embodiments of the imaging lens of the present invention are described with reference to the accompanying drawings. In addition, the reference symbols marked on the lenses in the cross-sectional views of each embodiment are used independently in each embodiment to avoid the complication of the description and drawings caused by the increase in the number of digits of the reference symbols. Therefore, even if the same reference symbols are marked in the drawings of different embodiments, they are not necessarily the same structure.

[0210] [Example 1]

[0211] A cross-sectional view of the structure of the imaging lens according to Example 1 is shown in FIG. Fig. 9 The imaging lens according to Example 1 includes, from the object side to the image side, a first lens group having positive power, an aperture stop St, a second lens group having positive power, and a third lens group having positive power. The front group GF includes the first lens group. The rear group GR includes the second lens group and the third lens group. When focusing from an infinitely distant object to the nearest object, the first lens group and the third lens group are fixed relative to the image plane Sim, and the second lens group moves toward the object side.

[0212] The Lp lens Lp is included in the second lens component from the object side of the second lens group. This lens component is a cemented lens formed by cementing the Lp lens Lp and a negative lens in this order from the object side.

[0213] Regarding the imaging lens of Example 1, the basic lens data is shown in Table 4, the specifications and variable surface spacing are shown in Table 5, and the aspheric coefficients are shown in Table 6. The table of basic lens data is described as follows. The Sn column shows the surface number when the surface closest to the object side is set as the first surface and the number increases one by one toward the image side. The R column shows the radius of curvature of each surface. The D column shows the surface spacing on the optical axis between each surface and the surface adjacent to its image side. The Nd column shows the refractive index of each component relative to the d-line. The vd column shows the Abbe number of each component based on the d-line. In the θgF column, the partial dispersion ratio between the g-line and the F-line of the lens corresponding to the Lp lens Lp is shown. Surfaces 23 to 24 in Table 4 correspond to the Lp lens Lp.

[0214] In the table of basic lens data, the sign of the curvature radius of the surface of the shape of the convex surface facing the object side is set to positive, and the sign of the curvature radius of the surface of the shape of the convex surface facing the image side is set to negative. In the surface number column corresponding to the aperture stop St, the surface number and the term (St) are recorded. The value at the bottom of the surface spacing column in the table is the distance between the surface closest to the image side in the table and the image plane Sim. Regarding the variable surface spacing during focusing, the symbol DD[] is used, and the surface number on the object side of the interval is marked in [] and recorded in the surface spacing column.

[0215] In the data of each table, "° (degree)" is used as the unit of angle, and "mm (millimeter)" is used as the unit of length, but since the optical system can be used even if it is scaled up or scaled down, other appropriate units can also be used. In addition, in each table shown below, the values ​​obtained by rounding off with a predetermined number of digits are recorded.

[0216] [Table 4]

[0217]

[0218]

[0219] [Table 5]

[0220]

[0221] [Table 6]

[0222] Sn 1 2 12 KA -4.9999975823E+00 9.0564499476E-01 2.5371050465E+00 A3 0.0000000000E+00 0.0000000000E+00 0.0000000000E+00 A4 1.8214983670E-04 1.8388965999E-04 -6.5211177486E-05 A5 -3.4244624298E-06 -1.8762601085E-06 1.3633242991E-06 A6 -1.2301757446E-06 -1.2385930540E-06 -1.2299846544E-06 A7 2.9432370541E-08 5.6831868528E-08 2.0556710164E-07 A8 8.3614322746E-09 -6.0521473761E-09 -1.6366710547E-08 A9 -3.9140250344E-10 1.3062411976E-09 1.2029432851E-09 A10 -2.1962871606E-11 -6.4939571064E-11 3.3217765134E-10 A11 1.3915091110E-12 -2.4154579269E-12 -2.7986191823E-11 A12 5.6937541161E-14 2.9965861021E-13 8.7546237963E-13 A13 -5.6566615280E-15 -2.4642394464E-14 7.8541685018E-14 A14 1.0205912739E-16 2.4876232625E-15 -1.5015800142E-14 A15 1.6343011697E-18 -1.2497757724E-16 9.7849756602E-16 A16 -5.0315251508E-20 2.1603907341E-18 -2.2520121427E-17

[0223] Sn 13 30 31 KA 2.7612794169E+00 -4.9999923706E+00 -1.2578112734E+00 A3 0.0000000000E+00 0.0000000000E+00 0.0000000000E+00 A4 -4.4375078142E-05 -6.2769511042E-05 -4.3420069731E-07 A5 1.0292208120E-06 -1.6084967699E-05 -3.1030626290E-05 A6 -1.2628959508E-06 -2.3976158449E-07 7.5495741509E-06 A7 3.5587774346E-07 2.0472115339E-06 -6.5947958849E-07 A8 -5.7267643913E-08 -6.6393294070E-07 -1.2024285236E-08 A9 1.9176178614E-09 1.1485550600E-07 8.1095245052E-09 A10 7.4597799195E-10 -1.3010334758E-08 -7.6871341504E-10 A11 -1.0708694061E-10 1.1529399919E-09 5.7207680308E-11 A12 1.6123113957E-12 -9.8355998392E-11 -5.6441254551E-12 A13 8.4723078464E-13 8.0210706727E-12 3.8115245910E-13 A14 -9.0398540898E-14 -4.9610049476E-13 -9.8936689597E-15 A15 4.0294842301E-15 1.8489150694E-14 -1.0082645116E-16 A16 -7.1250896502E-17 -3.0203642417E-16 6.5247839855E-18

[0224] [Example 2]

[0225] The cross-sectional view of the structure of the imaging lens of Example 2 is shown in Fig.11 The imaging lens of Example 2 includes, from the object side to the image side, a first lens group having negative power, a second lens group having positive power, and a third lens group having negative power. The second lens group includes an aperture stop St. The front group GF includes the first lens group and a portion of the object side of the second lens group. The rear group GR includes the other portion of the second lens group and the third lens group. When focusing from an object at infinity to the nearest object, the first lens group and the third lens group are fixed relative to the image plane Sim, and the second lens group moves toward the object side.

[0226] The Lp lens Lp is included in the second lens component from the object side of the second lens group. This lens component is a cemented lens formed by cementing the Lp lens Lp and a negative lens in this order from the object side.

[0227] Regarding the imaging lens of Example 2, basic lens data is shown in Table 7, specifications and variable surface spacing are shown in Table 8, aspheric coefficients are shown in Table 9, and various aberration diagrams are shown in Table 10. Fig.12 The 12th and 13th surfaces in Table 7 correspond to the Lp lens Lp.

[0228] [Table 7]

[0229] Sn R D Nd vd θgF 1 -61.9356 1.5000 1.51742 52.43 2 73.4976 1.5000 *3 85.9038 7.0001 1.58313 59.46 *4 -73.9171 DD[4] 5 50.3273 5.5000 1.85150 40.78 6 -494.8646 1.5100 1.59551 39.24 7 70.5210 4.0000 8(St) ∞ 8.4049 9 -43.7729 1.2100 1.59551 39.24 10 30.5775 5.0973 1.75500 52.32 11 446.3743 4.1107 *12 -39.6052 0.7000 1.59833 20.31 0.83435 13 -34.2307 1.0000 1.59551 39.24 14 -122.8152 0.3000 *15 71.7128 5.5000 1.69350 53.20 *16 -75.0791 0.3002 17 272.6236 1.2700 1.59551 39.24 18 43.5277 11.8057 1.49700 81.54 19 -36.7266 DD

[19] 20 158.8561 8.5014 1.88300 40.76 21 -41.7059 1.5202 1.59551 39.24 22 57.9998 10.4174 23 -30.8126 1.0001 1.48749 70.24 24 -101.9347 18.1847 25 ∞ 3.2000 1.51680 64.20 26 ∞ 1.1000

[0230] [Table 8]

[0231]

[0232] [Table 9]

[0233] Sn 3 4 12 KA 1.0000000000E+00 1.0000000000E+00 1.0000000000E+00 A4 8.6904290127E-07 5.9860796378E-08 1.1308276598E-06 A6 -1.1987878195E-10 -7.2246335077E-10 -2.6508000748E-09 A8 3.5992754959E-12 5.5888485740E-12 3.2224981708E-11 A10 -1.8012445782E-14 -1.6756476564E-14 -3.1159637629E-14 A12 7.9205331672E-17 2.6863603430E-17 -1.9559123272E-16 A14 -2.1161023857E-19 -4.0164086941E-20 -4.0528177081E-19 A16 5.5185491788E-23 -6.4360277265E-24 2.9581367171E-21 A18 8.6153654828E-25 3.4852187355E-25 1.1319301414E-24 A20 -1.2011528525E-27 -5.7770438841E-28 -1.8662849379E-26

[0234] Sn 15 16 KA 1.0000000000E+00 1.0000000000E+00 A4 1.6158007609E-06 1.1103698543E-05 A6 1.7249994397E-08 1.3404604776E-08 A8 1.2697856462E-12 4.3806760569E-11 A10 -1.0145016313E-13 -1.3923488524E-13 A12 7.6980281811E-16 7.4016856579E-17 A14 -9.1138966591E-19 2.2240070362E-18 A16 -3.4281048434E-21 -3.4835878582E-21 A18 1.1769482782E-23 -1.6118651444E-23 A20 -2.8338709546E-27 4.8803969327E-26

[0235] The above embodiments and examples are used to illustrate the technology of the present invention, but the technology of the present invention is not limited to the above embodiments and examples, and various modifications are possible. For example, the radius of curvature, surface spacing, refractive index, Abbe number and aspheric coefficient of each lens are not limited to the values ​​shown in the above embodiments, and other values ​​can be used.

[0236] All documents, patent applications, and technical standards described in this specification are incorporated herein by reference to the same extent as if each document, patent application, and technical standard was specifically and individually indicated to be incorporated by reference.

[0237] Regarding the above embodiment, the following supplementary notes are further disclosed.

[0238] (Note 1)

[0239] An optical system according to a first aspect, wherein:

[0240] The first lens is formed of a photocurable and thermosetting resin.

[0241] (Note 2)

[0242] An optical system according to a first aspect, wherein:

[0243] The linear expansion coefficient of the first lens is 6×10 -5 / ℃,

[0244] The elastic modulus of the first lens is 2.5×10 9 Pa,

[0245] The linear expansion coefficient of the second lens is 0.77×10 -5 / ℃,

[0246] The elastic modulus of the second lens is 106.7×10 9 pa.

[0247] (Note 3)

[0248] An optical system according to a first aspect, wherein:

[0249] The difference between the thickness of the first lens at the center of the convex surface and the thickness of the first lens on the first surface is 0.01 mm or more and 1 mm or less,

[0250] The effective diameter of the convex surface is 3 mm or more and 50 mm or less.

[0251] The outer diameter of the second lens is not less than 4 mm and not more than 110 mm,

[0252] The thickness of the second lens at the center of the concave surface is not less than 0.5 mm and not more than 10 mm,

[0253] The effective diameter of the concave surface is 3 mm or more and 50 mm or less.

[0254] The curvature radius of the concave surface is greater than or equal to 5 mm and less than or equal to 300 mm.

Claims

1. An optical system comprising a composite lens having a first lens and a second lens, wherein: The first lens is formed of resin, The second lens is made of glass. The maximum value of the thickness of the first lens is set to A [mm], When the minimum value of the thickness of the first lens is set to B [mm], The optical system satisfies the following conditional expressions (1) and (2): A / B≤10 (1) A≤3mm(2) When the plastic deformation amount when the indenter is pressed at a load rate of 200 mN / 10 sec at an ambient temperature of 25°C is defined as x [μm], The resin satisfies the conditional formula (3) represented by the following, 1.0μm≤x≤4.0μm (3).

2. The optical system according to claim 1, which satisfies the following conditional expressions (5) and (6): A≥0.1mm(5) B≥0.02mm(6).

3. The optical system according to claim 1 or 2, wherein: The resin has a hardness at 25° C. of 186 MPa or more and 196 MPa or less.

4. The optical system according to any one of claims 1 to 3, wherein: The resin has a hardness at 75° C. of 149 MPa or more and 164 MPa or less.

5. The optical system according to any one of claims 1 to 4, wherein: The resin has an elastic recovery rate at 75° C. of 59% or more and 63% or less.

6. The optical system according to any one of claims 1 to 5, wherein: The resin has an indentation elastic modulus at 25° C. of 3.5 GPa or more and 3.6 GPa or less.

7. The optical system according to any one of claims 1 to 6, wherein: The resin has an indentation elastic modulus of 2.4 GPa or less at 75°C.

8. The optical system according to any one of claims 1 to 7, wherein: The resin has photocurability and thermosetting property.

9. The optical system according to any one of claims 1 to 8, wherein: The first lens is a lens having positive refractive power and formed of resin. The center thickness of the first lens is set to d, The curvature radius of the object-side surface of the first lens is denoted by Rf. When the curvature radius of the image-side surface of the first lens is denoted by Rr, The optical system satisfies the conditional equation (7) expressed as follows: 0 <d×(1 / Rf-1 / Rr)<0.05 (7)。 10. The optical system according to any one of claims 1 to 9, wherein: The optical system comprises a front group, an aperture stop and a rear group, The front group, the aperture stop, and the rear group are arranged in this order from the object side to the image side, The rear group includes at least one Lp lens having positive power and formed of resin, The first lens is the Lp lens, The sum of the distance on the optical axis from the lens surface closest to the object side of the front group to the lens surface closest to the image side of the rear group in a state of focusing on an infinitely distant object and the air-converted distance on the optical axis from the lens surface closest to the image side of the rear group to the image plane is set to TL, When the focal length of the Lp lens is set to fp, The optical system satisfies the conditional equation (8) expressed as follows: 0.1<TL / fp<1.2 (8).

11. The optical system according to any one of claims 1 to 10, wherein: The optical system comprises a front group, an aperture stop and a rear group, The front group, the aperture stop, and the rear group are arranged in this order from the object side to the image side, The rear group includes at least one Lp lens having positive power and formed of resin, The first lens is the Lp lens, The height of the principal ray of the maximum half viewing angle on the object side surface of the Lp lens in the state of focusing on an infinitely distant object from the optical axis is set to Hpp. When the height of the axial marginal ray from the optical axis on the object side surface of the Lp lens in a state of focusing on an infinitely distant object is denoted as Hpm, The optical system satisfies the conditional equation (9) expressed as follows: 0.2 <Hpp / Hpm<1.1 (9)。 12. An optical system according to any one of claims 1 to 11, wherein: The optical system comprises a front group, an aperture stop and a rear group, The front group, the aperture stop, and the rear group are arranged in this order from the object side to the image side, The rear group includes at least one Lp lens having positive power and formed of resin, The first lens is the Lp lens, The curvature radius of the image-side surface of the Lp lens is denoted by Rr. When the point on the optical axis located at the position of the aperture stop is set as the object point in a state where the object is focused on an infinitely distant object, the distance on the optical axis from the image point formed by the optical system from the lens surface adjacent to the image side of the aperture stop to the image side surface of the Lp lens to the image side surface of the Lp lens is set as De, When De is calculated as air, if the image point is located on the optical axis at a position closer to the object side than the image side surface of the Lp lens, the sign of De is set to negative, and if the image point is located at a position closer to the image side than the image side surface of the Lp lens, the sign of De is set to positive. The optical system satisfies the conditional equation (10) expressed as follows: -0.9<(De-Rr) / (De+Rr)<0.9 (10).

13. An optical system according to any one of claims 1 to 12, wherein: The optical system comprises a front group, an aperture stop and a rear group, The front group, the aperture stop, and the rear group are arranged in this order from the object side to the image side, The rear group includes at least one Lp lens having positive power and formed of resin, The first lens is the Lp lens, The focal length of the focus group moving along the optical axis during focusing is set to ffoc. When the focal length of the Lp lens is set to fp, The optical system satisfies the conditional equation (11) represented by: 0.04 <ffoc / fp<0.36(11)。 14. An optical system according to any one of claims 1 to 13, wherein: The optical system comprises a front group, an aperture stop and a rear group, The front group, the aperture stop, and the rear group are arranged in this order from the object side to the image side, The first lens is an Lp lens having positive refractive power and formed of resin. When the maximum angle of view when focusing on an object at infinity is ωm, When the conditional expression (12) expressed by the following is satisfied, the rear group includes the Lp lens, ωm≥45° (12) When the conditional expression (13) expressed by the following is satisfied, the front group includes the Lp lens, ωm<45° (13).

15. An optical system according to any one of claims 1 to 14, wherein: The optical system comprises a front group, an aperture stop and a rear group, The front group, the aperture stop, and the rear group are arranged in this order from the object side to the image side, The rear group includes at least one Lp lens having positive power and formed of resin, The first lens is the Lp lens, The center thickness of the Lp lens is set to A, The thickness of the composite lens in the optical axis direction at the height of the maximum effective diameter on both surfaces of the Lp lens is set to B, Set the maximum image height to Y, The partial dispersion ratio between the g-line and the F-line of the Lp lens is θgF, The d-line-based Abbe number of the Lp lens is set to vd, When ΔθgF is expressed by conditional expression (14), Δ θgF=θgF-(0.6438-0.001682×vd)(14) The optical system satisfies the conditional equation (15) expressed as follows: 0.004<(AB| ΔθgF) / Y<0.020(15).

16. An optical system according to any one of claims 1 to 15, wherein: The optical system comprises a front group, an aperture stop and a rear group, The front group, the aperture stop, and the rear group are arranged in this order from the object side to the image side, The composite lens is included in the front group, The second lens is arranged on the object side with respect to the first lens.

17. An optical system according to any one of claims 1 to 15, wherein: The optical system comprises a front group, an aperture stop and a rear group, The front group, the aperture stop, and the rear group are arranged in this order from the object side to the image side, The compound lens is included in the rear group, The second lens is arranged on the image side with respect to the first lens.

18. An optical system comprising a composite lens having a first lens and a second lens, wherein: The first lens has a convex surface and a first surface protruding from an outer peripheral edge of the convex surface toward the outside in the radial direction of the composite lens. The second lens has a concave surface bonded to the convex surface and a second surface protruding from the outer peripheral edge of the concave surface toward the outside in the radial direction and bonded to the first surface. When the length of the first surface along the radial direction is a [μm], the length of the second surface along the radial direction is b [μm], and the surface roughness of the second surface is Ra [μm], The optical system satisfies the following conditional expressions (16) and (17): a<b(16) 5μm≤a / Ra(17).

Images