Lens unit and camera module

Abstract

The lens unit includes: a plurality of lenses; and a cylindrical housing member that houses the plurality of lenses. The plurality of lenses are arranged in order from the opening of the housing member, and the outermost lens, among the plurality of lenses, located on the opening side of the housing member includes: a plastic lens; an anti-reflection film disposed on at least one surface side of the plastic lens; and a hard coating layer between the plastic lens and the antireflection film. The lens unit further includes a light shielding member that shields an outer edge of the outermost lens.

Description

TECHNICAL FIELD

[0001] The present application relates to a lens unit and a camera module. BACKGROUND

[0002] In order to protect a light-transmissive plastic lens substrate, a technique is known in which a hard coat layer harder than the plastic lens substrate is overlaid on the plastic lens substrate, and an antireflection layer is provided on the surface of the hard coat layer to prevent reflection of light (see, for example, Patent Literature 1).

[0003] Patent Literature 1 describes a plastic lens used as a spectacle lens, the plastic lens including an antireflection layer on a hard coat layer that overlies a plastic lens substrate. In the plastic lens of Patent Literature 1, the antireflection layer is a multilayer film in which a low-refractive-index film composed of silicon dioxide (Si02) and a high-refractive-index film composed of silicon nitride (Si3N4) are alternately laminated, and by setting the low-refractive-index film and the high-refractive-index film of the antireflection layer to specific film thicknesses, it is possible to improve the durability quality of the plastic lens.

[0004] PRIOR ART DOCUMENTS

[0005] PATENT LITERATURE

[0006] Patent Literature 1: Japanese Published Patent Application No. 2008-76598 SUMMARY

[0007] PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] However, even the plastic lens of Patent Literature 1 can be subject to peeling of the antireflection layer or damage to the hard coat layer due to the surrounding environment, resulting in a decrease in the durability of the optical element.

[0009] The present application has been achieved in view of the above-described problems, and aims to provide a lens unit and a camera module that can improve durability.

[0010] TECHNICAL SOLUTION TO THE PROBLEM

[0011] An exemplary lens unit of the present application includes a plurality of lenses, and a cylindrical housing member that houses the plurality of lenses. The plurality of lenses are arranged in order from an opening of the housing member, and an outermost lens of the plurality of lenses on the opening side of the housing member includes a plastic lens, an antireflection film arranged on at least one face side of the plastic lens, and a hard coat layer between the plastic lens and the antireflection film. The lens unit further includes a light-shielding member that light-shields an outer edge of the outermost lens.

[0012] An exemplary camera module of the present application includes the above-described lens unit and an imaging element.

[0013] EFFECT OF THE INVENTION

[0014] The present invention can be exemplified by providing a lens unit and camera module that can improve durability. Attached Figure Description

[0015] Figure 1A This is a schematic diagram of the camera module in this embodiment.

[0016] Figure 1B yes Figure 1A A magnified view of a portion of the image.

[0017] Figure 2 yes Figure 1A A magnified view of a portion of the image.

[0018] Figure 3A This is an exploded view of the camera module in this embodiment.

[0019] Figure 3B This is a schematic diagram illustrating the manufacturing process of the camera module according to this embodiment.

[0020] Figure 3C This is a schematic diagram illustrating the camera module of this embodiment. Detailed Implementation

[0021] The lens unit and camera module according to embodiments of the present invention will now be described with appropriate reference to the accompanying drawings. In the drawings, the same or equivalent parts are labeled with the same symbols and will not be described again. The dimensions, shapes, and size relationships between constituent elements in the drawings may not be the same as the actual dimensions, shapes, and size relationships between constituent elements. In particular, the thicknesses of the lens unit, anti-reflective film, hard coating, and plastic lens in the drawings may differ significantly from the actual thicknesses of the lens unit, anti-reflective film, hard coating, and plastic lens. In this specification, the "thickness" of various parts of the optical element refers to the length of the optical element parallel to the optical axis.

[0022] The following will refer to Figure 1A and Figure 1B The camera module 200 of this embodiment will be described. Figure 1A This is a schematic diagram illustrating an example of the camera module 200 according to this embodiment. Figure 1B yes Figure 1A A magnified view of a portion of the surrounding environment. The camera module 200 captures images of the surrounding environment.

[0023] like Figure 1A As shown, the camera module 200 includes a lens unit 100 and an image sensor 210. The image sensor 210 receives light passing through the lens unit 100 and captures an image of the surrounding environment.

[0024] The lens unit 100 has an optical axis Lx. Light enters the lens unit 100 along the direction of the optical axis Lx.

[0025] The lens unit 100 includes a plurality of lenses 110. At least one of the plurality of lenses 110 is an optical element 10.

[0026] The plurality of lenses 110 include a first lens 110a, a second lens 110b, a third lens 110c, a fourth lens 110d, and a fifth lens 110e. The first lens 110a, the second lens 110b, the third lens 110c, the fourth lens 110d, and the fifth lens 110e are arranged in this order from the object side to the image side.

[0027] For example, the first lens 110a is an optical element 10. The optical element 10 has a curved shape. Typically, the optical element 10 has a spherical shape. The optical element 10 has a spherical shape centered on a central axis.

[0028] Optical element 10 has an optical axis Lx. The optical axis Lx passes through the center of the curved shape of optical element 10. Optical element 10 has a symmetrical structure about the optical axis Lx. Typically, optical element 10 has a rotationally symmetric structure centered on the optical axis Lx. Light enters optical element 10 along the direction of the optical axis Lx.

[0029] The optical element 10 includes a plastic lens 11, a hard coating 12, and an anti-reflective film 13. The plastic lens 11, the hard coating 12, and the anti-reflective film 13 are stacked in this order. Typically, the plastic lens 11, the hard coating 12, and the anti-reflective film 13 are arranged in close proximity in this order.

[0030] The plastic lens 11 is made of resin. The plastic lens 11 transmits light. Here, the plastic lens 11 has a curved shape.

[0031] An anti-reflective film 13 is disposed on at least one surface side of the plastic lens 11. The anti-reflective film 13 covers a hard coating 12. The anti-reflective film 13 suppresses the reflection of light incident on the anti-reflective film 13. The anti-reflective film 13 suppresses at least a portion of the light traveling in the direction incident on the plastic lens 11 from being reflected on the surface side of the plastic lens 11.

[0032] A hard coating 12 is located between the plastic lens 11 and the antireflective film 13. The hard coating 12 covers the plastic lens 11. The hard coating 12 has a higher hardness than the plastic lens 11. The hard coating 12 gives the plastic lens 11 scratch resistance and improves the adhesion between the plastic lens 11 and the antireflective film 13.

[0033] The lens unit 100 also includes a housing component 120, a filter 130, a sealing component 140, and a light-shielding component 150. The housing component 120 is cylindrical. Typically, the housing component 120 is cylindrical. The inner circumferential surface of the housing component 120 may be provided with irregularities.

[0034] The housing component 120 houses multiple lenses 110 and filters 130. The housing component 120 is formed of an opaque component. For example, the housing component 120 is formed of a component that does not allow visible light and ultraviolet light to pass through.

[0035] A first lens 110a, a second lens 110b, a third lens 110c, a fourth lens 110d, and a fifth lens 110e are disposed in a receiving member 120. At least a portion of at least one of the first lens 110a, second lens 110b, third lens 110c, fourth lens 110d, and fifth lens 110e may be configured to protrude from the receiving member 120. For example, the first lens 110a is configured to protrude at least a portion from the receiving member 120, while the other two lenses 110b, third lens 110c, fourth lens 110d, and fifth lens 110e are disposed within the receiving member 120. The first lens 110a is the outermost lens among the plurality of lenses 110 located on the opening side of the receiving member 120.

[0036] Here, the diameter of the first lens 110a is larger than the diameters of the second lens 110b, the third lens 110c, the fourth lens 110d, and the fifth lens 110e. The diameter of the fifth lens 110e is larger than the diameters of the second lens 110b, the third lens 110c, and the fourth lens 110d.

[0037] The filter 130 is disc-shaped. The filter 130 selectively transmits incident light. For example, the filter 130 selectively transmits light of a specific wavelength in the incident light. Here, the filter 130 is disposed in the housing member 120. For example, the imaging element 210 is disposed outside the lens unit 100.

[0038] Filter 130 is disposed on the image side of the fifth lens 110e. Filter 130 can select the wavelength of light reaching the imaging element 210. The imaging element 210 is a photoelectric conversion element that converts incident light into an electrical signal. The imaging element 210 is, for example, a CMOS image sensor or a CCD image sensor. However, the imaging element 210 is not limited to these. The imaging element 210 captures an image of a subject formed by multiple lenses 110. The imaging element 210 can be disposed on the image side of the filter 130 (lens unit 100).

[0039] The first lens 110a is a negative meniscus lens with its convex surface facing the object side. In this embodiment, the object-side surface of the first lens 110a, which is composed of convex surfaces, is spherical, and the image-side surface, which is composed of concave surfaces, is aspherical.

[0040] The second lens 110b, the third lens 110c, the fourth lens 110d, and the fifth lens 110e can be made of resin (plastic lens) or glass.

[0041] The second lens 110b, the third lens 110c, the fourth lens 110d, and the fifth lens 110e can be any of the following: a biconvex lens, a plano-convex lens, a convex meniscus lens, and a concave meniscus lens.

[0042] As described above, the lens unit 100 includes a plurality of lenses 110, at least one of which is an optical element 10, thus the degradation of the lenses 110 in the lens unit 100 can be suppressed.

[0043] Furthermore, since the first lens 110a, which includes the aforementioned plastic lens 11, hard coating 12, and anti-reflective film 13, is arranged to protrude from the housing member 120, while the remaining lenses (second lens 110b, third lens 110c, fourth lens 110d, and fifth lens 110e) are arranged inside the housing member 120, the degradation of the other lenses, except for the highly durable first lens 110a, can be suppressed.

[0044] The sealing member 140 deforms between the first lens 110a and the receiving member 120 to seal the gap between the first lens 110a and the receiving member 120. For example, the sealing member 140 is an annular elastomer. In one example, the sealing member 140 is an O-ring.

[0045] The lens unit 100 is suitable for use as a vehicle-mounted lens for photographing the area around a vehicle. For example, the lens unit 100 is used as a vehicle-mounted lens for photographing the rear or sides of a vehicle.

[0046] Since the lens unit 100 includes a sealing member 140, even if water splashes onto the lens unit 100 from the outside, water can be prevented from seeping into the interior of the lens unit 100 (i.e., the interior of the receiving member 120).

[0047] The first lens 110a includes a plastic lens 11, a hard coating 12, and an anti-reflective film 13, thereby appropriately suppressing ultraviolet rays entering the housing component 120. Therefore, it is possible to suppress the deterioration of the lens within the housing component 120.

[0048] The light-shielding member 150 blocks light from the first lens 110a. The light-shielding member 150 is annularly positioned, covering the periphery of the first lens 110a. This blocks light incident on the periphery of the first lens 110a. The light-shielding member 150 extends relative to the receiving member 120 in a direction orthogonal to the optical axis Lx. The light-shielding member 150 extends along the periphery of the first lens 110a. The light-shielding member 150 prevents the first lens 110a from detaching from the receiving member 120. The light-shielding member 150 can be a single component with the receiving member 120.

[0049] In this embodiment, the lens unit 100 includes a light-shielding member 150, which can prevent the first lens 110a from detaching from the housing member 120.

[0050] like Figure 1B As shown, the light-shielding member 150 covers the periphery of the first lens 110a. The length of the light-shielding member 150 covering the periphery of the first lens 110a is more than 0.5% and less than 10% of the diameter of the first lens 110a. Therefore, the effective diameter Ed of the first lens 110a is smaller than the diameter Ld of the first lens 110a.

[0051] For example, the diameter Ld of the first lens 110a is 1 mm or more and 100 mm or less, or it may be 2 mm or more and 50 mm or less. The length Sd of the light-shielding member 150 along the direction orthogonal to the optical axis Lx is 0.005 mm or more and 10 mm or less, or it may be 0.01 mm or more and 5 mm or less.

[0052] For example, the diameter Ld of the first lens 110a is 13.70 mm or more and 13.75 mm or less. In one example, the light-shielding member 150 covers the periphery of the first lens 110a within a length range of 0.1 mm or more and 1.0 mm or less from the outer edge of the first lens 110a. Therefore, the length Sd of the light-shielding member 150 along the direction orthogonal to the optical axis Lx is 0.1 mm or more and 1.0 mm or less. Therefore, the effective diameter Ed of the first lens 110a is 11.70 mm or more and 13.55 mm or less.

[0053] As described above, the lens unit 100 includes a plurality of lenses 110 and a cylindrical receiving member 120 for receiving the plurality of lenses 110. The plurality of lenses 110 are arranged sequentially from the opening of the receiving member 120. The outermost lens of the plurality of lenses 110 located on the opening side of the receiving member 120 includes: a plastic lens 11; an anti-reflective film 13 disposed on at least one surface side of the plastic lens 11; and a hard coating 12 located between the plastic lens 11 and the anti-reflective film 13. The lens unit 100 also includes a light-shielding member 150 for blocking light from the outer edge of the outermost lens.

[0054] By using the light-shielding component 150 to shield the outer edge of the hard coating 12, which is prone to becoming thinner, the decrease in adhesion at the interface between the antireflective film 13 and the hard coating 12 can be suppressed, as can the deterioration of the hard coating 12. This improves the weather resistance of the lens unit 100.

[0055] Generally, when a lens unit is exposed to ultraviolet radiation in an outdoor environment, the surface of the hard coating may deteriorate, leading to a decrease in adhesion at the interface between the hard coating and the antireflective film. Conversely, by providing a light-shielding member 150 on the lens unit 100 to block the outer edge of the outermost lens, even if light shines on the lens unit 100, peeling of the antireflective film 13 from the hard coating 12 and damage to the hard coating 12 can be prevented. Thus, an optical element 10 with excellent weather resistance can be provided.

[0056] In addition, since the light-shielding component 150 and the storage component 120 are a single component, the increase in the number of components used to shield the outer edge of the hard coating 12 can be suppressed.

[0057] The camera module 200 includes a lens unit 100 and an image sensor 210. This improves the weather resistance of the camera module 200.

[0058] The following will refer to Figure 2 The lens unit 100 of this embodiment is described. Figure 2 yes Figure 1A A magnified view of a portion of the image.

[0059] like Figure 2 As shown, the optical element 10 includes a plastic lens 11, a hard coating 12, and an anti-reflective film 13. The plastic lens 11, hard coating 12, and anti-reflective film 13 are stacked in this order. Typically, the plastic lens 11, hard coating 12, and anti-reflective film 13 are arranged in close contact in this order.

[0060] [Plastic Lens 11]

[0061] The plastic lens 11 transmits light. For example, the plastic lens 11 is transparent. The plastic lens 11 can also be translucent, or it can be light-transmitting.

[0062] Typically, the plastic lens 11 is made of resin. The plastic lens 11 can be composed of a single component. For example, the plastic lens 11 contains a resin having a cyclic imide structure as a ring structure. Examples of such resins include AZP manufactured by Asahi Kasei Corporation, and RM-104, RM-250, and RM-100-Z manufactured by Nippon Shokubai Corporation.

[0063] The plastic lens 11 has a curved shape. Typically, the plastic lens 11 has a spherical shape. At least one surface of the plastic lens 11 can be convex or concave. When the plastic lens 11 has a convex or concave surface, the plastic lens 11 functions as a lens (specifically, for example, a biconvex lens, a plano-convex lens, a convex meniscus lens, and a concave meniscus lens).

[0064] The plastic lens 11 may have a convex surface. For example, the radius of curvature of the plastic lens 11 is 9 mm or more and 16 mm or less.

[0065] The coefficient of thermal expansion of the plastic lens 11 is preferably 60 ppm / K or higher and 150 ppm / K or lower. This helps to suppress the influence of thermal stress between the plastic lens 11 and the anti-reflective film 13.

[0066] [Hard Coating 12]

[0067] A hard coating 12 covers the plastic lens 11. For example, the hard coating 12 covers one side (e.g., the air side) of the plastic lens 11 located on the object side in the direction of extension of the optical axis Lx. The hard coating 12 has a higher hardness than the plastic lens 11. The hard coating 12 imparts scratch resistance to the plastic lens 11 and improves the adhesion between the plastic lens 11 and the antireflective coating 13.

[0068] The hard coating 12 is translucent. For example, the hard coating 12 is transparent. The hard coating 12 can also be translucent or translucent.

[0069] The hard coating 12 may have a base layer. Typically, the base layer comprises an organic material layer or an organosilicon compound layer. In the hard coating 12, metal oxide particles may be dispersed in the base layer.

[0070] The elastic modulus of the hard coating 12 is preferably 5 GPa or higher and 12 GPa or lower. By making the elastic modulus of the hard coating 12 5 GPa or higher, damage to the plastic lens 11 can be suppressed. In addition, by making the elastic modulus of the hard coating 12 12 GPa or lower, cracks in the hard coating 12 due to temperature changes can be suppressed.

[0071] Typically, the hard coating 12 can be formed by drying the component liquid adhering to the surface of the plastic lens 11, and then curing the thin film of the component liquid using electromagnetic waves such as ultraviolet light or electron beams. The component liquid can be heated during the drying process.

[0072] In one example, the hard coating 12 can be formed by spin coating. In this case, the component liquid of the hard coating 12 is sprayed onto a plastic lens 11 that rotates at a specified rotation speed, and the component liquid of the hard coating 12 is irradiated with electromagnetic waves such as ultraviolet light or electron beams to solidify the component liquid.

[0073] Alternatively, the hard coating 12 can also be formed by an immersion method. In this case, the plastic lens 11 is immersed in the component liquid of the hard coating 12, and then the component liquid of the hard coating 12 on the plastic lens 11, which is rotating at a specified rotation speed, is cured by electromagnetic waves such as ultraviolet light or an electron beam.

[0074] When a hard coating 12 is formed on the surface of the plastic lens 11 while the plastic lens 11 is being rotated, the thickness of the hard coating 12 varies depending on the distance from the optical axis Lx. Typically, the thickness of the hard coating 12 decreases as the distance from the optical axis Lx increases.

[0075] [Anti-reflective film 13]

[0076] An antireflective film 13 covers the hard coating 12. For example, the antireflective film 13 covers the air side of the hard coating 12. The antireflective film 13 suppresses the reflection of light incident on the antireflective film 13. The antireflective film 13 suppresses at least a portion of light traveling in the direction incident on the plastic lens 11 from being reflected at the surface side of the plastic lens 11. For example, the antireflective film 13 suppresses the reflection of visible light traveling in the direction incident on the plastic lens 11 from being reflected at the surface side of the plastic lens 11.

[0077] The anti-reflective film 13 allows light to pass through. For example, the anti-reflective film 13 is transparent. The anti-reflective film 13 can also be translucent or light-transmitting.

[0078] The thickness of the antireflective film 13 is greater than 100 nm and less than 1000 nm. The thickness of the antireflective film 13 can also be greater than 200 nm and less than 900 nm, or greater than 300 nm and less than 800 nm.

[0079] The coefficient of thermal expansion of the antireflective film 13 is preferably 1 ppm / K or higher and 10 ppm / K or lower. This allows for the suppression of the effects of thermal stress between the plastic lens 11 and the antireflective film 13.

[0080] The antireflective film 13 may have a laminated film structure. For example, layers with different compositions are laminated in the antireflective film 13.

[0081] For example, the antireflective film 13 is made of inorganic oxides. Examples of inorganic oxides in the antireflective film 13 include metal oxides such as silicon oxide, titanium oxide, lanthanum titanate, tantalum oxide, and niobium oxide. For example, layers of various metal oxides are stacked in the antireflective film 13.

[0082] For example, the antireflective film 13 includes a high-refractive-index film and a low-refractive-index film. The antireflective film 13 is composed of alternating layers of high-refractive-index and low-refractive-index films.

[0083] A high-refractive-index film has a higher refractive index than a low-refractive-index film. Generally, in the visible light range, the refractive index of a high-refractive-index film is higher than that of a low-refractive-index film.

[0084] The high-refractive-index film includes silicon tetranitride (Si3N4). The low-refractive-index film includes silicon dioxide (SiO2). Thus, the high-refractive-index film contains silicon tetranitride (Si3N4), and the low-refractive-index film contains silicon dioxide (SiO2), thereby improving thermal shock resistance.

[0085] For example, a high refractive index film has a refractive index of 1.9 or higher. In one example, a high refractive index film has a refractive index of 1.9 or higher and a refractive index of 2.3 or lower.

[0086] For example, a low-refractive-index film has a refractive index greater than 1.5 and less than 1.8. In one example, a low-refractive-index film has a refractive index greater than 1.6 and less than 1.75.

[0087] The thickness of the high-refractive-index film and the low-refractive-index film is 5 nm or more and 200 nm or less. This allows for the uniform formation of the high-refractive-index film and the low-refractive-index film, and enables the arrangement of multiple high-refractive-index films and low-refractive-index films within the anti-reflective film 13. The thickness of the high-refractive-index film and the low-refractive-index film can also be 10 nm or more and 180 nm or less, or 20 nm or more and 170 nm or less.

[0088] The antireflective film 13 preferably transmits light in the visible light range while reflecting light in the ultraviolet light range. In the antireflective film 13, the average reflectance of the visible light wavelength is preferably lower than the average reflectance of the ultraviolet light wavelength.

[0089] From the viewpoint of further suppressing the influence of thermal stress between the plastic lens 11 and the anti-reflective film 13, it is preferable that the difference between the thermal expansion coefficients of the plastic lens 11 and the anti-reflective film 13 is relatively small. For example, it is preferable that the thermal expansion coefficient of the plastic lens 11 is 60 ppm / K or more and 100 ppm / K or less, and the thermal expansion coefficient of the anti-reflective film 13 is 5 ppm / K or more and 10 ppm / K or less.

[0090] like Figure 2 As shown, the plastic lens 11 has a curved shape. Here, one side of the plastic lens 11 is curved, and the other side is flat. The thickness of the plastic lens 11 varies depending on its distance from the optical axis Lx.

[0091] The thickness of the hard coating 12 varies depending on its distance from the optical axis Lx. Typically, the thickness of the hard coating 12 is greatest at the optical axis Lx, which is the center. In addition, the thickness of the hard coating 12 is typically smallest at the outer edge.

[0092] Typically, the thickness Lx2 of the outer edge of the hard coating 12 is less than the thickness Lx1 of the hard coating 12 at the optical axis Lx. However, it is preferable that the difference between the thickness Lx1 of the hard coating 12 at the optical axis Lx and the thickness Lx2 of the outer edge of the hard coating 12 is relatively small. For example, the difference between the thickness Lx1 of the hard coating 12 at the optical axis Lx and the thickness Lx2 of the outer edge of the hard coating 12 is preferably 15 μm or less, more preferably 6 μm or less.

[0093] If the thickness of the hard coating is small, the anti-reflective film may peel off from the hard coating or the hard coating may be damaged when the optical element is exposed to the outdoor environment and the adhesion at the interface between the hard coating and the anti-reflective film decreases, resulting in reduced durability of the lens unit. Therefore, within the range of the effective diameter Ed of the plastic lens 11, the minimum thickness of the hard coating 12 is preferably 2 μm or more.

[0094] For example, in the hard coating 12, the portion not covered by the light-shielding member 150 has a thickness Lx1e of 2 μm or more, while the portion of the hard coating 12 with a thickness (Lx2s) less than 2 μm is covered by the light-shielding member 150. This prevents a decrease in the durability of the optical element 10.

[0095] If the thickness of the hard coating at the optical axis Lx is large, optical distortion will occur in the optical element, and the optical characteristics of the lens unit may deteriorate. Furthermore, if the thickness of the hard coating at the optical axis Lx is further increased, the film state of the hard coating becomes uneven, and cracks may sometimes form within the hard coating. Therefore, within the effective diameter Ed of the plastic lens 11, the maximum thickness of the hard coating 12 is preferably 20 μm or less. Typically, the thickness Lx1 of the hard coating at the optical axis Lx is the maximum thickness of the hard coating 12. This suppresses the deterioration of the optical characteristics of the lens unit 100.

[0096] The lens unit 100 of this embodiment exhibits relatively small optical distortion and relatively high durability. Therefore, the optical element 10 is suitable for use in surveillance cameras or vehicle cameras. The optical element 10 can be used continuously even when the surveillance camera or vehicle camera is used in an outdoor environment for a long time.

[0097] In the lens unit 100 of this embodiment, the light-shielding member 150 blocks light from the portion of the hard coating 12 in the outermost lens where the thickness is less than 2 μm. By using the light-shielding member 150 to block light from the portion of the hard coating 12 where the thickness is less than 2 μm, the decrease in adhesion at the interface between the antireflective film 13 and the hard coating 12 can be suppressed, and the deterioration of the hard coating 12 can also be suppressed. This improves the weather resistance of the lens unit 100.

[0098] The lens unit 100 has an optical axis Lx. The thickness Lx1 of the hard coating 12 at the optical axis Lx is 2 μm or more and 20 μm or less. Thus, by making the thickness Lx1 of the hard coating 12 at the optical axis Lx 2 μm or more, peeling of the antireflective film 13 at the optical axis Lx, where a large amount of light passes through, can be suppressed. Furthermore, by making the thickness Lx1 of the hard coating 12 at the optical axis Lx 20 μm or less, optical distortion can be suppressed, and crack formation in the hard coating 12 can be suppressed. Therefore, a lens unit 100 with excellent weather resistance and suppressed degradation of optical properties can be provided.

[0099] Within the effective diameter Ed of the plastic lens 11, the minimum thickness of the hard coating 12 is 2 μm or more, and the maximum thickness of the hard coating 12 is 20 μm or less. Thus, by ensuring the minimum thickness of the hard coating 12 is 2 μm or more, the hard coating 12 can prevent the antireflective film 13 from peeling off due to temperature changes, even when exposed to outdoor environments. Furthermore, by ensuring the maximum thickness of the hard coating is 20 μm or less, optical distortion can be suppressed, and crack formation in the hard coating 12 can be prevented.

[0100] The elastic modulus of the hard coating 12 is 5 GPa or more and 12 GPa or less. In this way, by making the elastic modulus of the hard coating 12 5 GPa or more, damage to the plastic lens 11 can be prevented. In addition, by making the elastic modulus of the hard coating 12 12 GPa or less, cracks in the hard coating 12 due to temperature changes can be prevented.

[0101] The coefficient of thermal expansion of the plastic lens 11 is 60 ppm / K or higher and 150 ppm / K or lower. By making the coefficient of thermal expansion of the plastic lens 11 60 ppm / K or higher and 150 ppm / K or lower, the influence of thermal stress between the plastic lens 11 and the anti-reflective film 13 can be reduced.

[0102] The coefficient of thermal expansion of the antireflective film 13 is above 1 ppm / K and below 10 ppm / K. In this way, by making the coefficient of thermal expansion of the antireflective film 13 above 1 ppm / K and below 10 ppm / K, the influence of thermal stress between the plastic lens 11 and the antireflective film 13 can be reduced.

[0103] The coefficient of thermal expansion of the plastic lens 11 is 60 ppm / K or higher and 100 ppm / K or lower, and the coefficient of thermal expansion of the anti-reflective film 13 is 5 ppm / K or higher and 10 ppm / K or lower. By making the coefficient of thermal expansion of the plastic lens 11 60 ppm / K or higher and 100 ppm / K or lower, and the coefficient of thermal expansion of the anti-reflective film 13 5 ppm / K or higher and 10 ppm / K or lower, the influence of thermal stress between the plastic lens 11 and the anti-reflective film 13 can be further reduced.

[0104] The difference between the thickness of the portion of the hard coating 12 along the optical axis Lx and the thickness of its outer edge is less than 15 μm. In this way, by making the difference between the thickness of the portion of the hard coating 12 along the optical axis Lx and the thickness of its outer edge less than 15 μm, a relatively thin hard coating 12 can be well formed on the surface of the plastic lens 11 while the component liquid of the hard coating 12 is rotated at a specified speed.

[0105] exist Figures 1A to 2 In the optical element 10 shown, the hard coating 12 and the anti-reflective film 13 are disposed on one side of the plastic lens 11, but this embodiment is not limited to this. The hard coating 12 and the anti-reflective film 13 can be disposed on both sides of the plastic lens 11.

[0106] Next, refer to Figure 1 to... Figure 3C The camera module 200 described in this embodiment is described. Figure 3A This is an exploded view of the camera module 200 according to this embodiment. Figure 3B This is a schematic diagram illustrating the manufacturing process of the camera module 200 in this embodiment. Figure 3C This is a schematic diagram showing the camera module 200 of this embodiment.

[0107] like Figure 3A As shown, the housing component 120 can house multiple lenses 110. At least one of the multiple lenses 110 is an optical element 10.

[0108] The storage component 120 is cylindrical. Typically, the storage component 120 is cylindrical.

[0109] The plurality of lenses 110 include a first lens 110a, a second lens 110b, a third lens 110c, a fourth lens 110d, and a fifth lens 110e. The storage member 120 has a storage section capable of storing the first lens 110a, the second lens 110b, the third lens 110c, the fourth lens 110d, and the fifth lens 110e respectively.

[0110] Here, a protrusion 150a is provided on the outer edge of one side of the storage member 120. Typically, the protrusion 150a is formed of the same material as the storage member 120. The protrusion 150a and the storage member 120 are a single component. The protrusion 150a extends from the storage member 120 parallel to the optical axis Lx.

[0111] like Figure 3BAs shown, the housing component 120 houses multiple lenses 110, a filter 130, and a sealing component 140. Here, the first lens 110a, the second lens 110b, the third lens 110c, and the sealing component 140 are inserted into the housing component 120 from one side to the other. The fourth lens 110d, the fifth lens 110e, and the filter 130 are inserted into the housing component 120 from the other side to one side. The filter 130 is located between the multiple lenses 110 and the imaging element 210.

[0112] like Figure 3C As shown, the light-shielding member 150 is formed by bending the protrusion 150a in a direction orthogonal to the optical axis Lx relative to the housing member 120. When the protrusion 150a is pressed in a heated state, it bends relative to the housing member 120 in a direction orthogonal to the optical axis Lx. The light-shielding member 150 blocks light from the outermost lens, i.e., the first lens 110a. The light-shielding member 150 suppresses light incident on the lens unit 100 from entering the outer edge of the first lens 110a. Furthermore, the light-shielding member 150 prevents the first lens 110a from detaching from the housing member 120.

[0113] Example

[0114] First, the lens unit 100 of Embodiment 1 will be described.

[0115] The material used is a plastic lens 11 of RM-104 manufactured by Nippon Shokubai Co., Ltd. The plastic lens 11 is a meniscus lens with the convex side facing the object side, and the outer diameter of the plastic lens 11 is approximately 14mm.

[0116] The surface of the plastic lens 11 is covered with a hard coating 12. The hard coating 12 is made of a photocurable resin material such as polyurethane. The hard coating 12 is formed as follows: a coating liquid is applied to the plastic lens 11 by spin coating, then the coating film formed by the coating liquid is heated and dried, and then the coating film is photocured using electromagnetic waves such as ultraviolet light or an electron beam.

[0117] The surface of the hard coating 12 is covered with an anti-reflective film 13. In the anti-reflective film 13, a high-refractive-index film composed of Si3N4 and a low-refractive-index film composed of SiO2 are alternately formed by sputtering. This fabricates the optical element 10. In the optical element 10, the thickness of the hard coating 12 at the optical axis Lx is 2.3 μm, and the thickness at the outer edge of the hard coating 12 is 0.5 μm.

[0118] Additionally, a housing component 120 is prepared, and a protrusion 150a extending along the optical axis Lx is provided. Then, the optical element 10 is housed in the housing component 120, and the protrusion 150a extending parallel to the optical axis Lx is bent relative to the housing component 120 in a direction orthogonal to the optical axis Lx, thereby forming a light-shielding component 150. In this way, the lens unit 100 of Embodiment 1 is manufactured.

[0119] Next, for the lens unit 100 of Embodiment 1, optical characteristic tests and weather resistance tests are conducted on the lens unit 100 under the following conditions.

[0120] [Optical property testing]

[0121] For the lens unit 100 of Embodiment 1, a fluorescent light source is used to visually inspect the optical distortion.

[0122] [Weather resistance test]

[0123] Weathering tests were conducted using a 7.5kW high-acceleration weathering tester with a super xenon gas atmosphere. The irradiance during the weathering tests was 180 W / m². 2 An 18-minute exposure followed by rainfall and then 102 minutes of separate exposure constitutes one cycle, which is repeated 500 times. During and after the weathering test, the antireflective film 13 is checked for peeling and the hard coating 12 is checked for damage.

[0124] Table 1 shows the thickness of the hard coating 12 at the optical axis and the thickness at the outer edge of the lens unit 100 in Example 1, as well as the results of optical characteristic tests and weather resistance tests of the lens unit 100. In this specification, cases where no optical distortion is observed during visual inspection under fluorescent light are indicated by "○", and cases where optical distortion is observed are indicated by "×". In this specification, cases where no peeling of the anti-reflective film or damage to the hard coating is found during visual inspection after the weather resistance test are indicated by "○", and cases where peeling of the anti-reflective film or damage to the hard coating is found are indicated by "×".

[0125] [Table 1]

[0126]

[0127] As shown in Table 1, in the lens unit 100 of Example 1, the thickness of the hard coating 12 at the optical axis Lx is 2.3 μm, and the thickness at the outer edge is 0.5 μm. The outer edge of the hard coating 12 is shielded by the light-shielding component 150. In the lens unit 100 of Example 1, the light transmitted through the lens unit 100 is not distorted. Furthermore, even after the weathering test, the antireflective film 13 did not peel off, and the hard coating 12 was not damaged.

[0128] Lens units of Examples 2-4 and Comparative Examples 1-4 were manufactured in the same manner as lens unit 100 of Example 1. Optical property tests and weather resistance tests were also conducted on lens units of Examples 2-4 and Comparative Examples 1-4 in the same manner as on lens unit 100 of Example 1. Table 1 shows the thickness of the hard coating at the optical axis and the thickness at the outer edge, as well as the results of the optical property tests and weather resistance tests, in lens units of Examples 2-4 and Comparative Examples 1-4.

[0129] In the lens unit 100 of Embodiment 2, the hard coating 12 has a thickness of 4.8 μm at the optical axis and a thickness of 1.4 μm at the outer edge, and the outer edge of the hard coating 12 is shielded by the light-shielding member 150. In the lens unit 100 of Embodiment 2, the light transmitted through the lens unit 100 is not distorted. Furthermore, even after the weathering test, the antireflective film 13 did not peel off, and the hard coating 12 was not damaged.

[0130] In the lens unit 100 of Example 3, the hard coating 12 has a thickness of 5.4 μm at the optical axis and a thickness of 2.1 μm at the outer edge, and the outer edge of the hard coating 12 is shielded by the light-shielding member 150. In the lens unit 100 of Example 3, the light transmitted through the lens unit 100 is not distorted. Furthermore, even after the weathering test, the antireflective film 13 did not peel off, and the hard coating 12 was not damaged.

[0131] In the lens unit 100 of Example 4, the hard coating 12 has a thickness of 15.8 μm at the optical axis and a thickness of 5.2 μm at the outer edge, and the outer edge of the hard coating 12 is shielded by the light-shielding member 150. In the lens unit 100 of Example 4, the light transmitted through the lens unit 100 is not distorted. Furthermore, even after the weathering test, the antireflective film 13 did not peel off, and the hard coating 12 was not damaged.

[0132] In the lens unit of Comparative Example 1, the thickness of the hard coating at the optical axis was 2.3 μm, and the thickness at the outer edge was 0.5 μm. No light-shielding was applied to the outer edge of the hard coating. No distortion occurred in the light transmitted through the lens unit of Comparative Example 1. On the other hand, after the weathering test, peeling of the anti-reflective film or damage to the hard coating occurred.

[0133] In the lens unit of Comparative Example 2, the thickness of the hard coating at the optical axis was 4.8 μm, and the thickness at the outer edge was 1.4 μm. No light-shielding was applied to the outer edge of the hard coating. No distortion occurred in the light transmitted through the lens unit of Comparative Example 2. On the other hand, after the weathering test, peeling of the anti-reflective film or damage to the hard coating occurred.

[0134] In the lens unit of Comparative Example 3, the thickness of the hard coating at the optical axis was 23.5 μm, and the thickness at the outer edge was 8.3 μm. No light-shielding was applied to the outer edge of the hard coating. Light transmitted through the lens unit of Comparative Example 3 was distorted. On the other hand, after the weathering test, the antireflective film did not peel off, and the hard coating remained undamaged.

[0135] In the lens unit of Comparative Example 4, the thickness of the hard coating at the optical axis was 33.9 μm, and the thickness at the outer edge was 10.2 μm. No light-shielding was applied to the outer edge of the hard coating. Light transmitted through the lens unit of Comparative Example 4 was distorted. Furthermore, after weathering tests, peeling of the anti-reflective film or damage to the hard coating occurred.

[0136] In the lens units 100 of Examples 1-4, there was no optical distortion, and no peeling of the antireflective film 13 or damage to the hard coating 12 occurred. On the other hand, in the lens units of Comparative Examples 1 and 2, although there was no optical distortion, peeling of the antireflective film or damage to the hard coating occurred. In the lens unit of Comparative Example 3, although neither peeling of the antireflective film nor damage to the hard coating occurred, optical distortion occurred. In the lens unit of Comparative Example 4, optical distortion occurred, and peeling of the antireflective film or damage to the hard coating occurred.

[0137] This technology can have the following structure.

[0138] (1) A lens unit, comprising: a plurality of lenses; and a cylindrical receiving member for receiving the plurality of lenses, wherein the plurality of lenses are arranged sequentially from an opening in the receiving member, and the outermost lens of the plurality of lenses located on the opening side of the receiving member comprises: a plastic lens; an anti-reflective film disposed on at least one surface side of the plastic lens; and a hard coating layer located between the plastic lens and the anti-reflective film, the lens unit further comprising a light-shielding member that shields the outer edge of the outermost lens.

[0139] (2) According to the lens unit of (1), wherein the light-shielding component shields the portion of the hard coating in the outermost lens where the thickness is less than 2 μm.

[0140] (3) The lens unit according to (1) or (2), wherein the lens unit has an optical axis and the thickness of the hard coating at the optical axis is more than 2 μm and less than 20 μm.

[0141] (4) The lens unit according to any one of (1) to (3), wherein the minimum thickness of the hard coating is more than 2 μm within the effective diameter of the plastic lens, and the maximum thickness of the hard coating is less than 20 μm within the effective diameter of the plastic lens.

[0142] (5) The lens unit according to any one of (1) to (4), wherein the elastic modulus of the hard coating is 5 GPa or more and 12 GPa or less.

[0143] (6) The lens unit according to any one of (1) to (5), wherein the coefficient of thermal expansion of the plastic lens is 60 ppm / K or more and 150 ppm / K or less.

[0144] (7) The lens unit according to any one of (1) to (6), wherein the coefficient of thermal expansion of the antireflective film is 1 ppm / K or more and 10 ppm / K or less.

[0145] (8) The lens unit according to any one of (1) to (7), wherein the coefficient of thermal expansion of the plastic lens is 60 ppm / K or more and 100 ppm / K or less, and the coefficient of thermal expansion of the anti-reflective film is 5 ppm / K or more and 10 ppm / K or less.

[0146] (9) The lens unit according to (3), wherein the difference between the thickness of the portion of the hard coating along the optical axis and the thickness of the outer edge is less than 15 μm.

[0147] (10) The lens unit according to any one of (1) to (9), wherein the light-shielding component and the housing component are a single component.

[0148] (11) A camera module comprising: a lens unit according to any one of (1) to (10); and an image sensor.

[0149] Symbol Explanation

[0150] 10 Optical Components

[0151] 11 Plastic Lenses

[0152] 12 Hard coating

[0153] 13 Anti-reflective film

[0154] 100 lens units

[0155] 110 lens

[0156] 120 storage components

[0157] 130 filter

[0158] 140 Sealing components

[0159] 150 Light-shielding components.

Claims

1. A lens unit, comprising: A plurality of lenses; and a cylindrical housing component for housing the plurality of lenses, characterized in that, The plurality of lenses are arranged sequentially from the opening of the housing component. The outermost lens located on the opening side of the receiving component among the plurality of lenses includes: Plastic lenses; An antireflective film disposed on at least one side of the plastic lens; and The hard coating located between the plastic lens and the antireflective film, The lens unit also includes a light-shielding component that blocks the light from the outermost edge of the outermost lens.

2. The lens unit according to claim 1, characterized in that, The light-shielding component blocks light from the portion of the hard coating in the outermost lens that has a thickness of less than 2 μm.

3. The lens unit according to claim 1 or 2, characterized in that, The lens unit has an optical axis. The thickness of the hard coating at the optical axis is greater than 2 μm and less than 20 μm.

4. The lens unit according to claim 1 or 2, characterized in that, Within the effective diameter range of the plastic lens, the minimum thickness of the hard coating is 2 μm or more. Within the effective diameter range of the plastic lens, the maximum thickness of the hard coating is less than 20 μm.

5. The lens unit according to claim 1 or 2, characterized in that, The elastic modulus of the hard coating is above 5 GPa and below 12 GPa.

6. The lens unit according to claim 1 or 2, characterized in that, The coefficient of thermal expansion of the plastic lens is above 60ppm / K and below 150ppm / K.

7. The lens unit according to claim 1 or 2, characterized in that, The coefficient of thermal expansion of the antireflective film is above 1 ppm / K and below 10 ppm / K.

8. The lens unit according to claim 1 or 2, characterized in that, The coefficient of thermal expansion of the plastic lens is above 60ppm / K and below 100ppm / K. The coefficient of thermal expansion of the antireflective film is above 5 ppm / K and below 10 ppm / K.

9. The lens unit according to claim 3, characterized in that, The difference between the thickness of the portion of the hard coating along the optical axis and the thickness of the outer edge is less than 15 μm.

10. The lens unit according to claim 1 or 2, characterized in that, The light-shielding component and the storage component are a single component.

11. A camera module, characterized in that, include: The lens unit as described in claim 1 or 2; as well as Camera components.

Images