Film-coated lens, lens unit and camera module

Abstract

To provide a lens with a film which has an antireflection film capable of having a desired antireflection characteristic within a specified incident wavelength range over the whole area inside and outside in a radial direction without largely increasing a film thickness throughout, a lens unit, and a camera module.SOLUTION: A lens 14 with a film has an antireflection film 40' on a surface 14b. The antireflection film 40' has a first antireflection film portion 40A inside in a radial direction and a second antireflection film portion 40B outside in the radial direction which have antireflection characteristics different from each other. The second antireflection film portion 40B has an antireflection characteristic whose reflectance is higher than that of the first antireflection film portion 40A within a specified incident wavelength range at a predetermined first light incident angle and whose reflectance is lower than that of the first antireflection film portion 40A within the specified incident wavelength range at a second light incident angle larger than the first light incident angle.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention particularly relates to a film-equipped lens, a lens unit, and a camera module that are provided in an on-board camera mounted on a vehicle such as an automobile. [Background technology]

[0002] In recent years, automobiles have been equipped with on-board cameras to assist with parking and prevent collisions through image recognition, and attempts have also been made to apply these to autonomous driving. Camera modules such as these on-board cameras generally include a lens unit having a lens group consisting of multiple lenses arranged along an optical axis, a lens barrel that houses and holds this lens group, and an aperture member arranged between at least one of the lenses in the lens group (see, for example, Patent Document 1).

[0003] The surfaces of the lenses that make up such lens units are generally provided with an anti-reflection coating (AR coating) by, for example, vapor deposition to increase their transmittance. Furthermore, when the anti-reflection coating has a multi-layer structure, it is generally possible to satisfy the desired low reflectance condition over a wide wavelength range by alternately laminating films made of low-refractive-index materials and films made of high-refractive-index materials. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-231993 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when an anti-reflection coating is formed by vapor deposition, depending on the deposition method, the thickness of the anti-reflection coating in the radially outer region may be thinner than that in the radially inner region (resulting in non-uniform deposition), due to factors such as the curvature of the lens surface to be coated. In particular, in a multilayer structure, such a non-uniformly thin anti-reflection coating region results in high reflectivity in the visible range (resulting in poor anti-reflection properties in the visible range). Specifically, for example, at the same incident light angle, the spectral characteristic curve showing the relationship between the reflectivity (%) of the anti-reflection coating and the incident light wavelength (nm) is shifted toward shorter wavelengths in the radially outer region of the anti-reflection coating compared to the radially inner region of the anti-reflection coating that is uniformly deposited and has the desired anti-reflection properties. As a result, the reflectivity does not completely fall below a predetermined value within a specified incident wavelength range (e.g., the visible light range from 450 nm to 650 nm) (the visible light reflectance becomes high). As a result, in such an anti-reflection film, the peripheral light intensity ratio deteriorates, and the desired optical characteristics (anti-reflection characteristics) cannot be obtained.

[0006] Thus, even if the radially inner region of the anti-reflection coating is deposited in the desired layered state, if the radially outer region of the anti-reflection coating is deposited unevenly and thinly relative to the radially inner region, the anti-reflection characteristics will differ between the radially inner and radially outer regions at the same light incidence angle (the desired anti-reflection characteristics will not be obtained in the radially outer region), making it difficult to achieve the desired overall optical performance. Of course, this problem can be solved, for example, by depositing the anti-reflection coating so that it satisfies the anti-reflection characteristics of both the radially inner and radially outer regions, i.e., so that it satisfies the desired low reflectivity condition over a wide wavelength range. However, this requires the use of a multilayer structure in which films of low-refractive index material and films of high-refractive index material are alternately laminated, as described above, resulting in a significant increase in film thickness. If the film thickness increases significantly, the anti-reflection coating may be unable to withstand deformation when the lens expands due to exposure to a high-temperature environment, such as during high-temperature testing, and cracks may form on the film surface. These cracks can cause ghosting and adversely affect optical properties.

[0007] The present invention has been made in consideration of the above circumstances, and aims to provide a coated lens, a lens unit, and a camera module with an anti-reflection coating that can have desired anti-reflection properties within a specified incident wavelength range over the entire inner and outer radial regions without significantly increasing the film thickness over the entire area. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems, the present invention provides a film-coated lens that is provided in a lens barrel and has an anti-reflection film formed on its surface, the antireflection film has a first antireflection film portion on the inner side in the radial direction and a second antireflection film portion on the outer side in the radial direction, the first antireflection film portion having different antireflection properties from the second antireflection film portion, The second anti-reflection film portion is characterized by having anti-reflection properties in which, at a predetermined first light incident angle, the reflectance is higher than that of the first anti-reflection film portion within a specified incident wavelength range, and, at a second light incident angle larger than the first light incident angle, the reflectance is lower than that of the first anti-reflection film portion within a specified incident wavelength range.

[0009] According to the above configuration, the anti-reflection film is composed of a first anti-reflection film portion on the inside in the radial direction and a second anti-reflection film portion on the outside in the radial direction, which have different anti-reflection properties, and the anti-reflection properties of the second anti-reflection film portion are set so that at a predetermined first light incident angle, the reflectance is higher than that of the first anti-reflection film portion within a specified incident wavelength range, and at a second light incident angle larger than the first light incident angle, the reflectance is lower than that of the first anti-reflection film portion within the specified incident wavelength range (in other words, at a predetermined first light incident angle, the second anti-reflection film portion has a higher reflectance than that of the first anti-reflection film portion within the specified incident wavelength range). The antireflection properties of the first antireflection coating portion are set so that the reflectance is lower than that of the antireflection coating portion and higher than that of the second antireflection coating portion within a specified incident wavelength range at a second light incident angle larger than the first light incident angle, or alternatively, the reflectance of the first antireflection coating portion is lower than that of the second antireflection coating portion within a specified incident wavelength range at a specified first light incident angle, and the reflectance of the second antireflection coating portion is lower than that of the first antireflection coating portion within a specified incident wavelength range at a second light incident angle larger than the first light incident angle. That is, the anti-reflection film is divided into the inner and outer radial regions by forming separate anti-reflection film portions suitable for each region so as to satisfy the anti-reflection characteristics required in each of the radially inner and outer regions of the lens. Specifically, the outer radial region, which generally has a relatively large light incidence angle (particularly applicable to lenses such as camera lenses having a concave-convex spherical lens configuration), has a high transmittance at large light incidence angles, and the inner radial region, which has a relatively small light incidence angle, has a high transmittance at small light incidence angles. This allows the desired anti-reflection characteristics to be maintained within a specified incident wavelength range throughout the entire inner and outer radial regions. This avoids the situation where the anti-reflection characteristics of the outer radial region are deteriorated due to the thin film state of the outer radial region, as occurs when the anti-reflection film has the same film layer configuration throughout the entire inner and outer radial regions. Furthermore, it is not necessary to employ a thick multilayer structure for the anti-reflection film to satisfy the desired low reflectance condition over a wide wavelength band so as to satisfy the anti-reflection characteristics of both the inner and outer radial regions.

[0010] In addition, in such an anti-reflection coating, the second anti-reflection coating portion generally has a larger thickness than the first anti-reflection coating portion. In this case, the first and second anti-reflection coating portions may have the same film layer configuration but different film thicknesses in the multilayer structure, or may have different film layer configurations. In the above configuration, the extent of each of the radially outer and inner regions of the anti-reflection coating is determined by the curvature and effective diameter of the lens. The greater the lens curvature, the smaller the extent of the radially inner region. Here, the effective diameter of the lens refers to the diameter of a circle whose radius is the distance from the optical axis of the light ray passing through the lens surface at the position farthest from the optical axis.

[0011] It is also preferable that the first anti-reflection coating portion and the second anti-reflection coating portion do not overlap each other. In this case, the boundary between the first anti-reflection coating portion and the second anti-reflection coating portion may form a gap or a step, or may form a transition portion that gradually transitions from the first anti-reflection coating portion to the second anti-reflection coating portion. However, the present invention does not exclude the first anti-reflection coating portion and the second anti-reflection coating portion overlapping each other. If they overlap each other, the first anti-reflection coating portion may form an underlying layer of the second anti-reflection coating portion in the multilayer structure.

[0012] In the above configuration, the anti-reflection coating is provided by, for example, vapor deposition within at least the optically effective range (effective diameter) of the lens. In the above configuration, the coated lens with the anti-reflection coating may be made of glass or resin. In the above configuration, the anti-reflection coating may be provided not only on the surface of the lens facing the object side, but also on the back surface of the lens facing the image side. In the above configuration, the "prescribed incident wavelength range" is preferably the wavelength range of visible light, particularly 450 nm to 650 nm. The first light incident angle may be, for example, 0°, and the second light incident angle may be, for example, 45°.

[0013] In the above-described configuration of the present invention, when the coated lens has a radially inward central surface that is spherically concave toward the object side and an annular outer peripheral surface that extends radially outward from the outer periphery of the central surface on the image side, it is preferable that a first anti-reflection coating portion be formed on the central surface and a second anti-reflection coating portion be formed from the radially outer region of the central surface to the radially inner region of the outer peripheral surface within the lens effective diameter. In the above-described configuration of the present invention, it is preferable that the first anti-reflection coating portion has lower incidence angle dependence than the second anti-reflection coating portion within a predetermined first light incidence angle range, and that the second anti-reflection coating portion has lower incidence angle dependence than the first anti-reflection coating portion within a second light incidence angle range larger than the first light incidence angle range. Incident angle dependence is defined as the degree of change in reflectance (reflectance within a specified incident wavelength range) with respect to changes in light incidence angle. For example, low incidence angle dependence indicates a small degree of change in reflectance.

[0014] The present invention also provides a lens unit having the above-mentioned film-coated lens, and a camera module having this lens unit. Such a lens unit and camera module can also provide the same effects as the above-mentioned film-coated lens. [Effects of the Invention]

[0015] According to the present invention, the anti-reflection film is composed of a first anti-reflection film portion on the radially inner side and a second anti-reflection film portion on the radially outer side, which have different anti-reflection properties, and the anti-reflection properties of the second anti-reflection film portion are set so that at a predetermined first light incident angle, the second anti-reflection film portion has a higher reflectance than the first anti-reflection film portion within a specified incident wavelength range, and at a second light incident angle larger than the first light incident angle, the second anti-reflection film portion has a lower reflectance than the first anti-reflection film portion within the specified incident wavelength range, so that the desired anti-reflection properties can be obtained within the specified incident wavelength range throughout the entire radial inner and outer regions. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a schematic cross-sectional view of a lens unit with a film-coated lens according to an embodiment of the present invention. [Figure 2] 2 is a cross-sectional view showing a state in which an anti-reflection film is formed on a coated lens that constitutes a lens group of the lens unit of FIG. 1. FIG. [Figure 3] 2 is a schematic cross-sectional view of a camera module including the lens unit of FIG. 1. [Figure 4] FIG. 3 is a table showing detailed data on the laminated structure of the anti-reflection film formed on the coated lens of FIG. 2. [Figure 5] 5 is a graph showing the spectral characteristics of the first and second antireflection film portions that form the laminated structure of FIG. 4 when the light incident angle is 0°. FIG. [Figure 6] 5 is a graph showing the spectral characteristics of the first and second antireflection film portions that form the laminated structure of FIG. 4 when the light incident angle is 45°. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In this embodiment, desired anti-reflection properties can be obtained within a specified incident wavelength range over the entire inner and outer radial regions, contributing to "9. Build resilient infrastructure, promote inclusive and sustainable industrialization, promote innovation and build resilient infrastructure" of the Sustainable Development Goals (SDGs) advocated by the United Nations. The lens unit of the present embodiment described below is particularly intended for use in a camera module such as an in-vehicle camera, and is fixedly installed on the exterior surface of a vehicle, with wiring leading into the vehicle and connected to a display or other devices. Hatching of the lens is omitted in Figures 1 to 3.

[0018] 1 shows a lens unit 11 according to one embodiment of the present invention. As shown, lens unit 11 of this embodiment includes a cylindrical lens barrel 12 made of, for example, resin, and a plurality of lenses arranged in a stepped inner storage space S of lens barrel 12, for example, five lenses consisting of, from the object side, a first lens 13, a second lens 14, a third lens 15, a fourth lens 16, and a fifth lens 17. An in-vehicle camera equipped with such lens unit 11 includes lens unit 11, a board having an image sensor (not shown), and an installation member (not shown) for installing the board on a vehicle such as an automobile.

[0019] The multiple lenses 13, 14, 15, 16, and 17 incorporated and housed within the internal housing space S of the lens barrel 12 are stacked and arranged with their optical axes aligned, and the lenses 13, 14, 15, 16, and 17 are arranged along a single optical axis O to form a group of lenses L used for imaging. In this case, the first lens 13, which is positioned closest to the object and is a spherical glass lens with a convex surface facing the object side and a concave surface facing the image side, and the other lenses 14, 15, 16, and 17 are resin lenses, but are not limited to this. The lens barrel 12 may also be made of metal.

[0020] Furthermore, the present invention, including this embodiment, is characterized by a coated lens having an anti-reflection coating formed thereon, and the number of lenses, the materials of the lenses and lens barrel, etc. can be set arbitrarily depending on the application, etc. Furthermore, in this embodiment, the two fourth and fifth lenses 16 and 17 located on the image side are cemented lenses, but this does not have to be the case.

[0021] In this embodiment, an O-ring 26 serving as a seal is interposed between the first lens 13, which is positioned closest to the object, and the lens barrel 12 to prevent water and dust from entering the lens group L inside the lens barrel 12. In this case, a stepped reduced-diameter portion 13b, whose diameter is reduced at the image-side portion of the first lens 13, is provided on the outer circumferential surface 13a of the first lens 13. An O-ring 26 is attached to this reduced-diameter portion 13b, and the O-ring 26 is compressed radially between the outer circumferential surface 13a of the first lens 13 and the inner circumferential surface 12c of the lens barrel 12, thereby sealing the object-side end of the lens barrel 12. The seal interposed between the first lens 13 and the lens barrel 12 is not limited to an O-ring, and may be any shape as long as it is an annular body that can seal the gap between the first lens 13 and the lens barrel 12.

[0022] The lens barrel 12 has a cylindrical inner wall 12b on the object side. A groove 18 is formed between the inner wall 12b and the outer wall 12a. A ring-shaped body 27 is provided within the groove 18, and an O-ring 26 is in close contact with the ring-shaped body 27. The groove 18 is formed between the inner wall 12b and the outer wall 12a to prevent significant sink marks and dimensional inaccuracies from occurring during molding and cooling of the resin lens barrel 12, which would otherwise be caused by the thick wall if the inner wall 12b and the outer wall 12a were integrated without a groove. The ring-shaped body 27 is made of a relatively soft, elastic material, such as Teflon. The ring-shaped body 27 functions to support the O-ring 26 in the optical axis direction. Because the ring-shaped body 27 is a separate component from the lens barrel 12, it can be changed to a ring-shaped body 27 of different heights depending on the size of the O-ring 26, ensuring that the O-ring 26 provides a seal with appropriate elasticity.

[0023] Furthermore, with lens group L incorporated and housed within inner housing space S of lens barrel 12, crimping portion 23 at the object-side end (upper end in FIG. 1) is thermally crimped radially inward, thereby fixing first lens 13, which is positioned closest to the object side of lens group L, to the object-side end of lens barrel 12 in the optical axis direction by crimping portion 23. In this case, to ensure stable crimping, the portion of glass lens 13 to which crimping portion 23 is pressed is formed as flat portion 13c, which is cut diagonally in a planar shape.

[0024] Furthermore, an inner flange portion 24 having an opening with a diameter smaller than that of fifth lens 17 is provided at the image side end (the lower end in FIG. 1) of lens barrel 12. The multiple lenses 13, 14, 15, 16, and 17 that make up lens group L within lens barrel 12 are held and fixed in the optical axis direction by this inner flange portion 24 and crimped portion 23.

[0025] The inner diameter of lens barrel 12 gradually decreases from the object side to the image plane side. Correspondingly, the outer diameters of lenses 13, 14, 15, 16, and 17 gradually decrease from the object side to the image plane side. Basically, the outer diameters of lenses 13, 14, 15, 16, and 17 are approximately equal to the inner diameters of the portions of lens barrel 12 where lenses 13, 14, 15, 16, and 17 are supported. An outer flange 25 is provided on the outer peripheral surface of lens barrel 12 in the shape of a brim and is used when installing lens barrel 12 in an on-board camera.

[0026] In this embodiment, at least one of the lenses 13, 14, 15, 16, and 17 that make up lens group L is configured as a coated lens having an anti-reflection coating on its surface, and the following will describe in detail the coating configuration of second lens 14, which is a coated lens having an anti-reflection coating formed on its surface, but it goes without saying that similar coating configurations can be applied to the other lenses 13, 15, 16, and 17. For simplicity, the anti-reflection coatings formed on the other lenses 13, 15, 16, and 17 are not shown in Figures 1 and 3.

[0027] As clearly shown in the enlarged view in Figure 2, the second lens (made of resin in this embodiment, but may be made of glass) 14 has a surface 14a facing the object side, which is a combination of a radially inner central surface 14aa that is slightly spherically concave toward the image side and an annular outer peripheral surface 14ab that extends (extends aspherically) outward in a substantially radial direction from the outer peripheral edge of this central surface 14aa, and a surface 14b facing the image side, which is a combination of a radially inner central surface 14ba that is spherically concave toward the object side (concave with a larger curvature than the central surface 14aa) and an annular outer peripheral surface 14bb that extends (extends) outward in a substantially radial direction from the outer peripheral edge of this central surface 14aa.

[0028] An antireflection coating 40 (which may be the same as a first antireflection coating portion 40A, which will be described later) is formed by, for example, vapor deposition on the object-side surface 14a of the second lens 14, covering the entire central surface 14aa and the radially inner region of the outer circumferential surface 14ab. Meanwhile, an antireflection coating 40' is also formed by, for example, vapor deposition on the image-side surface 14b of the second lens 14, and in this case, the antireflection coating 40' is composed of a first antireflection coating portion 40A on the radially inner side and a second antireflection coating portion 40B on the radially outer side, which have different antireflection properties. Specifically, within the effective diameter of the second lens 14, the first anti-reflection film portion 40A is formed as a multilayer structure over almost the entire area except for a portion of the radially outer region of the central surface 14ba, while the second anti-reflection film portion 40B is formed as a multilayer structure from the radially outer region of the central surface 14ba to the radially inner region of the outer peripheral surface 14bb so as not to overlap with the first anti-reflection film portion 40A. Here, the second anti-reflection film portion 40B has anti-reflection properties in which, at a predetermined first light incident angle, it has a higher reflectance than the first anti-reflection film portion 40A within a specified incident wavelength range, and, at a second light incident angle larger than the first light incident angle, it has a lower reflectance than the first anti-reflection film portion 40A within the specified incident wavelength range.

[0029] An example of the film layer configuration (film stack structure) of the first and second antireflection film sections 40A, 40B for achieving such antireflection properties is shown in Figure 4. As shown in the figure, the first antireflection film section 40A is formed on the material (e.g., ZEONEX (registered trademark) F52R with a refractive index of 1.54) that forms the second lens 14. The first antireflection film section 40A has a stack structure (here, a six-layer structure; from bottom to top, the thicknesses are 6.75 nm (ZrO), 14.28 nm (SiO), 33.76 nm (ZrO), 9.52 nm (SiO), 76.30 nm (ZrO), and 85.69 nm (SiO)) in which ZrO with a refractive index of 2.00 and SiO with a refractive index of 1.42 are alternately stacked on top of a bottom SiO layer with a thickness of 26.33 nm and a refractive index of 1.54. Meanwhile, the second anti-reflection coating portion 40B is formed on the material forming the second lens 14 (e.g., ZEONEX® F52R, with a refractive index of 1.54). The layer structure is a six-layer structure (here, the thicknesses from bottom to top are 13.44 nm (ZrO), 51.68 nm (SiO), 48.07 nm (ZrO), 17.62 nm (SiO), 85.27 nm (ZrO), and 112.93 nm (SiO)). As can be seen from this layer structure, the thickness of the second anti-reflection coating portion 40B (total thickness 363.60 nm) is clearly greater than the thickness of the first anti-reflection coating portion 40A (total thickness 252.63 nm). The formation of such first and second anti-reflection film portions 40A, 40B is carried out, for example, by first masking the radially outer region of the image-side surface 14b of the lens 14 (the region where the second anti-reflection film portion 40B is to be formed) and forming the first anti-reflection film portion 40A by vapor deposition, and then masking the radially inner region of the surface 14b (the region where the first anti-reflection film portion 40A is formed) and forming the second anti-reflection film portion 40B by vapor deposition.

[0030] The film stack structure of the first and second antireflection film portions 40A and 40B was optimized by a predetermined simulation at a predetermined light incidence angle. The spectral characteristic curves shown in FIGS. 5 and 6 (spectral characteristic diagrams showing the relationship between the reflectance (%) of the antireflection film and the wavelength (nm) of incident light) were obtained. The spectral characteristic curve L1 represents the first antireflection film portion 40A, and the spectral characteristic curve L2 represents the second antireflection film portion 40B. Specifically, FIG. 5 shows the optimization performed by the predetermined simulation at a light incidence angle of 0°, while FIG. 6 shows the optimization performed by the predetermined simulation at a light incidence angle of 45°. As can be seen from FIG. 5, at the small first light incidence angle of 0°, the second antireflection film portion 40B (spectral characteristic curve L2) has a higher reflectance than the first antireflection film portion 40A (spectral characteristic curve L1) within the specified incident wavelength range, which is at least 450 nm to 600 nm. In other words, the first antireflection film portion 40A has a lower reflectance than the second antireflection film portion 40B at least within the incident wavelength range of 450 nm to 600 nm. That is, the reflectance of the first antireflection film portion 40A is lower than the reflectance of the second antireflection film portion 40B at least within the incident wavelength range of 450 nm to 600 nm. Of course, the specified incident wavelength range that satisfies such antireflection properties can be varied by adjusting the film layer configuration and the thickness of each layer. However, at a light incident angle of 0°, it is preferable that the reflectance of the first antireflection film portion 40A be lower than the reflectance of the second antireflection film portion 40B at least within the incident wavelength range of 450 nm to 650 nm.

[0031] On the other hand, as can be seen from FIG. 6, at the larger second light incident angle of 45°, the second antireflection film portion 40B (spectral characteristic curve L2) has a lower reflectance than the first antireflection film portion 40A (spectral characteristic curve L1) within the specified incident wavelength range, in this case, within the incident wavelength range of 450 nm or more (exhibiting characteristics such as maintaining a minimum reflectance over a wide wavelength band (approximately 450 nm to approximately 650 nm in the figure)). In other words, the first antireflection film portion 40A has a higher reflectance than the second antireflection film portion 40B within the incident wavelength range of 450 nm or more. That is, within the incident wavelength range of 450 nm or more, the reflectance of the second antireflection film portion 40B is lower than the reflectance of the first antireflection film portion 40A. In this case, as before, the specified incident wavelength range that satisfies such anti-reflection properties can be varied by adjusting the film layer configuration and the thickness of each layer, but at a light incident angle of 45°, it is preferable that the reflectance of the second anti-reflection film portion 40B be lower than the reflectance of the first anti-reflection film portion 40A at least within the incident wavelength range of 450 nm to 650 nm.

[0032] Although the light incidence angles shown here are 0° and 45°, it is preferable that the above antireflection characteristics be satisfied for other light incidence angles. In addition to the above, in this embodiment, it is preferable that the first antireflection film portion 40A has lower incidence angle dependency than the second antireflection film portion 40B within a predetermined first light incidence angle range, and it is also preferable that the second antireflection film portion 40B has lower incidence angle dependency than the first antireflection film portion 40A within a second light incidence angle range that is larger than the first incident angle range.

[0033] Moreover, Fig. 3 is a schematic cross-sectional view of a camera module 300 of this embodiment having the lens unit 11 of Fig. 1. As shown in the figure, the camera module 300 is configured to include the lens unit 11 to which the filter 100 is attached.

[0034] Camera module 300 includes upper case (camera case) 301, which is an exterior component, and mount (base) 302, which holds lens unit 11. Camera module 300 also includes seal member 303 and package sensor (image sensor) 304, which serves as an imaging element.

[0035] Upper case 301 is a member that exposes the object-side end of lens unit 11 and covers the other portions. Mount 302 is disposed inside upper case 301, and has female threads 302a that mesh with male threads 11a of lens unit 11. Sealing member 303 is a member that is interposed between the inner surface of upper case 301 and outer peripheral surface 12d of barrel 12 of lens unit 11, and is a member that maintains airtightness inside upper case 301.

[0036] Package sensor 304 is disposed inside mount 302 and is positioned to receive the image of the object formed by lens unit 11. Package sensor 304 also includes a CCD, CMOS, or the like, and converts the light that is collected and reaches it through lens unit 11 into an electrical signal. The converted electrical signal is then converted into analog data or digital data, which are components of the image data captured by the camera.

[0037] As described above, in the coated lens 14 of this embodiment, the anti-reflection coating 40′ is composed of a first anti-reflection coating portion 40A on the radially inner side and a second anti-reflection coating portion 40B on the radially outer side, which have different anti-reflection properties, and the anti-reflection properties of the second anti-reflection coating portion 40B are set so that it has a higher reflectance than the first anti-reflection coating portion 40A within a specified incident wavelength range at a predetermined first light incident angle and a lower reflectance than the first anti-reflection coating portion 40A within the specified incident wavelength range at a second light incident angle larger than the first light incident angle. Therefore, the desired anti-reflection properties can be obtained within the specified incident wavelength range throughout the entire radially inner and outer regions.

[0038] Although one embodiment of the present invention has been described above, the present invention can be embodied in various modifications without departing from the spirit and scope of the invention. For example, the shapes of the lenses, lens barrels, etc., in the present invention are not limited to those in the above-described embodiment. Furthermore, the anti-reflection coating on the lens may be formed in any form as long as it has the above-described function. Furthermore, some or all of the above-described embodiments may be combined, or part of the configuration may be omitted from one of the above-described embodiments, without departing from the spirit and scope of the invention. [Explanation of symbols]

[0039] 11 Lens unit 12 Telescope tube 14 Lens (membrane lens) 14ba center plane 14bb outer surface 40,40' Anti-reflection coating 40A First anti-reflection film portion 40B Second anti-reflection film portion 300 Camera Module L lens group

Claims

1. A film-coated lens provided in a lens barrel and having an anti-reflection film formed on its surface, a surface facing the image side that is a combination of a radially inner central surface that is spherically recessed toward the object side and an annular outer peripheral surface that extends outward in a substantially radial direction from an outer peripheral edge of the central surface, the anti-reflection film has a first anti-reflection film portion on the inner side in the radial direction and a second anti-reflection film portion on the outer side in the radial direction, the first anti-reflection film portion having different anti-reflection properties from the second anti-reflection film portion, Within the lens effective diameter, the first anti-reflection film portion is formed in a multilayer structure over the entire area except for a portion of the radially outer area of ​​the central surface, and the second anti-reflection film portion is formed in a multilayer structure separate from the first anti-reflection film portion over the area from the radially outer area of ​​the central surface to the radially inner area of ​​the outer peripheral surface so as not to overlap with the first anti-reflection film portion, thereby dividing the anti-reflection film into an inner area and an outer area in the radial direction, a first anti-reflection film portion having a thickness greater than that of the first anti-reflection film portion within a specified incident wavelength range at a predetermined first light incident angle, and a second anti-reflection film portion having a thickness greater than that of the first anti-reflection film portion within a specified incident wavelength range at a second light incident angle greater than the first light incident angle, the second anti-reflection film portion having a thickness greater than that of the first anti-reflection film portion within a specified incident wavelength range at a predetermined first light incident angle, and a thickness greater than that of the first anti-reflection film portion within a specified incident wavelength range at a second light incident angle greater than the first light incident angle, the second anti-reflection film portion having a thickness greater than that of the first anti-reflection film portion within a specified incident wavelength range at a predetermined ...

2. The lens with a film as described in claim 1 further has a surface facing the object side which is a combination of a radially inner central surface which is spherically concave toward the image side and an annular outer peripheral surface which extends aspherically from the outer peripheral edge of this central surface to the outside in an approximately radial direction, and the first anti-reflection film portion is formed on this surface facing the object side over the entire central surface and the radially inner region of the outer peripheral surface.

3. 3. The lens with a film according to claim 2, wherein the central surface of the surface facing the image side is concave with a larger curvature than the central surface of the surface facing the object side.

4. 2. The lens with a film according to claim 1, wherein the second anti-reflection film portion has a thickness greater than that of the first anti-reflection film portion.

5. 5. The lens with a film according to claim 1, wherein the specified incident wavelength range is 450 nm to 650 nm.

6. 6. The lens with a film according to claim 1, wherein the first light incident angle is 0° and the second light incident angle is 45°.

7. A lens unit comprising a lens group in which a plurality of lenses are arranged along the optical axis of the lenses, and a lens barrel in which the lens group is housed, A lens unit, wherein at least one of the lenses constituting the lens group is the film-coated lens according to any one of claims 1 to 6.

8. A camera module comprising the lens unit according to claim 7.

Images