Lens unit and camera module

Abstract

To provide a lens unit capable of preventing fogging of a back surface of a first lens by reliably waterproofing a space between the first lens located on the most object side and a lens barrel without using an O-ring, and to provide a camera module.SOLUTION: A first lens 13 located on the most object side among a plurality of lenses and a lens barrel 12 are waterproof bonded together using a low-moisture-permeability adhesive ad, thereby reliably waterproofing a space between the first lens 13 and the lens barrel 12 without using an O-ring to prevent fogging of a back surface of the first lens 13.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a lens unit and a camera module that can constitute an in-vehicle camera mounted on a vehicle such as an automobile.

Background Art

[0002] There is known a technique in which a camera mounted on a vehicle (in-vehicle camera) images a scenery outside the vehicle, and the captured image is displayed on a monitor or the like mounted inside the vehicle. Since the lens unit of the in-vehicle camera is in a state where the side facing the imaging target (object side) is exposed to the outside of the vehicle, strength, waterproofness, chemical resistance, high-temperature durability, etc. are required. In addition, it is necessary to prevent the lens from fogging due to temperature changes.

[0003] Patent Document 1 discloses a lens unit that ensures an airtight state inside the lens barrel in order to prevent the lens from fogging. In this lens unit, four lenses are arranged side by side along the optical axis direction inside the lens barrel. On the object side, a sealability is realized by arranging an O-ring between the first lens on the most object side and the inner peripheral surface of the lens barrel. Also, on the image side (imaging element side), sealability is realized by attaching an optical filter to the lens barrel via an adhesive. Thus, the airtightness inside the lens barrel is ensured by the seal on the object side and the seal on the imaging side, and fogging of the lens is prevented.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] As mentioned above, if the first lens is waterproofed by an O-ring, and the O-ring is improperly fitted, such as getting caught in the lens barrel, moisture can easily enter the space on the back of the outermost lens (first lens) in a high-humidity environment, and when the outside temperature drops, the back of the outermost lens on the object side is prone to fogging due to condensation. Furthermore, since an O-ring needs to be incorporated into the telescope tube, the number of parts increases, and the installation of the O-ring is also time-consuming.

[0006] The present invention has been made in view of the above circumstances, and aims to provide a lens unit and camera module that can reliably waterproof the space between the first lens, which is located closest to the object, and the lens barrel without using an O-ring, thereby preventing fogging on the back surface of the first lens. [Means for solving the problem]

[0007] To solve the aforementioned problems, the present invention provides a lens unit comprising a plurality of lenses arranged along the optical axis and a lens barrel that houses and holds these plurality of lenses, The first lens, which is located closest to the object among the multiple lenses, and the lens barrel are bonded together with a low-moisture-permeability adhesive for waterproofing.

[0008] Examples of low-moisture-permeability adhesives include acrylic adhesives, epoxy adhesives, and olefin adhesives.

[0009] In this invention, the first lens, which is located closest to the object, and the lens barrel are bonded together with a low-permeability adhesive for waterproofing. Therefore, even without using an O-ring, moisture is less likely to enter the space on the back surface of the first lens, even in a high-humidity environment. Consequently, even when the outside temperature drops, fogging due to condensation on the back surface of the first lens can be prevented. Furthermore, since O-rings are not used, the number of parts does not increase, and there is no hassle in installing O-rings.

[0010] Furthermore, in the above configuration of the present invention, the outer surface of the first lens and the inner surface of the lens barrel may be bonded and waterproofed with the low-moisture-permeability adhesive.

[0011] The inner surface of the telescope tube may be roughened by sandblasting or other methods to increase the adhesive strength of the low-moisture-permeability adhesive.

[0012] With this configuration, the outer surface of the first lens and the inner surface of the lens barrel are bonded and waterproofed with a low-moisture-permeability adhesive, thus more reliably waterproofing moisture flowing from the object-side surface of the first lens to the outer surface.

[0013] Furthermore, in the above configuration of the present invention, a filling portion in which the low moisture permeability adhesive is filled may be provided extending in the circumferential direction on either the outer circumferential surface of the first lens or the inner circumferential surface of the lens barrel.

[0014] With this configuration, a low-moisture-permeability adhesive can be reliably filled between the outer surface of the first lens and the inner surface of the lens barrel to provide waterproofing, and it is possible to prevent the low-moisture-permeability adhesive from penetrating beyond the outer surface of the first lens or the inner surface of the lens barrel into the lens barrel.

[0015] Furthermore, in the above configuration of the present invention, the image-side end face of the first lens and the surface of the lens barrel intersecting the axial direction may be bonded and waterproofed with the low-moisture-permeable adhesive. The intersecting surfaces are preferably perpendicular to the axial direction of the lens barrel, but they may also be inclined with respect to that axial direction.

[0016] With this configuration, the image-side end face of the first lens and the surface intersecting the axial direction of the lens barrel are bonded and waterproofed with a low-moisture-permeability adhesive. Therefore, even if the low-moisture-permeability adhesive waterproofing the space between the outer surface of the first lens and the inner surface of the lens barrel is damaged by impact or the like, allowing moisture to enter the lens barrel, it is possible to reliably prevent that moisture from entering the space on the back surface of the first lens. In addition, since the low moisture permeability adhesives are present in both the axial direction of the lens barrel and the direction intersecting the axial direction, when an impact is applied to the lens unit, it becomes difficult for either of the low moisture permeability adhesives to be damaged, so the responsiveness to impacts is good.

[0017] Also, in the above-described configuration of the present invention, the low moisture permeability adhesive may have an elastic modulus of 1 to 1000 MPa and a Tg of 40°C to 60°C.

[0018] The elastic modulus indicates an index of the ease of moisture passage of the low moisture permeability adhesive. When the elastic modulus is less than 1 MPa, the flexibility of the low moisture permeability adhesive increases and moisture passes easily. On the other hand, when it exceeds 1000 MPa, the low moisture permeability adhesive becomes too hard and is likely to be damaged when receiving an impact. Therefore, it is preferable that the elastic modulus of the low moisture permeability adhesive is 1 to 1000 MPa. Tg is the glass transition temperature of the low moisture permeability adhesive. When Tg exceeds 60°C, the low moisture permeability adhesive becomes too hard and the first lens is likely to be damaged. On the other hand, when it is less than 40°C, the low moisture permeability adhesive becomes too soft and moisture passes easily (the waterproof property deteriorates). Therefore, it is preferable that Tg is 40°C to 60°C.

[0019] <00oooo79>According to such a configuration, the first lens located on the most object side and the lens barrel can be more reliably waterproofed by the low moisture permeability adhesive, and damage to the first lens can be prevented.

[0020] Also, the camera module according to the present invention is characterized by including the above-described lens unit. According to such a configuration, the operational effects of the above-described lens unit can be obtained in the camera module.

Effects of the Invention

[0021] According to the present invention, without using an O-ring between the first lens located on the most object side and the lens barrel, it is possible to surely waterproof and prevent fogging on the back surface of the first lens.

Brief Description of the Drawings

[0022] [Figure 1] This shows an embodiment of the present invention. (a) is a schematic cross-sectional view of a lens unit, and (b) is a cross-sectional view of a main part of a lens unit of a modified example. [Figure 2] It is a schematic cross-sectional view of a camera module. [Figure 3] This shows another embodiment of the present invention. (a) is a schematic half cross-sectional view of a lens unit, and (b) is a schematic half cross-sectional view of a lens unit of a modified example.

Embodiments for Carrying Out the Invention

[0023] [[ID=十五]] [[ID=十六]]Hereinafter, embodiments of the present invention will be described with reference to the drawings. [[ID=十七]] [[ID=十八]]The lens unit of the present embodiment described below is particularly for a camera module such as an in-vehicle camera. For example, it is fixedly installed on the outer surface side of an automobile, and the wiring is drawn into the automobile and connected to a display or other devices. [[ID=十九]] [[ID=二十]]The lens unit of the present embodiment described below is particularly for a camera module such as an in-vehicle camera. For example, it is fixedly installed on the outer surface side of an automobile, and the wiring is drawn into the automobile and connected to a display or other devices. Also, in all the figures, hatching of the lenses is omitted. [[ID=二十一]] [[ID=二十二]]

[0024] [[ID=二十三]] [[ID=二十四]]FIG. 1 shows a lens unit 11 according to an embodiment of the present invention. As shown in the figure, the lens unit 11 of the present embodiment includes, for example, a cylindrical lens barrel (barrel) 12 made of resin, and a plurality of lenses arranged in the stepped inner accommodation space S of the lens barrel 12. For example, from the object side (upper side in FIG. 1), there are five lenses including a first lens 13, a second lens 14, a third lens 15, a fourth lens 16, and a fifth lens 17, and two aperture members 22a and 22b. [[ID=二十五]] [[ID=二十六]]

[0025] [[ID=二十七]] It should be noted that in the above translation, for the tags ,

[0023] , , , , ,

[0024] , , ,

[0025] , , since they are just numbered tags without specific semantic content in the context, they are directly retained as they are in the translation to meet the requirement of preserving all 7 - digit tags exactly as - is. Also, for the repeated text in item 18 and 20, it is translated as presented without making redundant adjustments.Of the two aperture members 22a and 22b, the first aperture member 22a from the object side is positioned between the second lens 14 and the third lens 15. The second aperture member 22b from the object side is positioned between the third lens 15 and the fourth lens 16. The aperture members 22a and 22b are either "aperture diaphragms" that limit the amount of transmitted light and determine the F-number, which is an indicator of brightness, or "light-shielding diaphragms" that block light rays that cause ghosting or light rays that cause aberrations. An in-vehicle camera equipped with such a lens unit 11 comprises the lens unit 11, a substrate having an image sensor (not shown), and mounting members (not shown) for mounting the substrate in a vehicle such as an automobile.

[0026] Multiple lenses 13, 14, 15, 16, and 17, which are incorporated and housed within the inner housing space S of the lens barrel 12, are stacked and arranged with their respective optical axes aligned. Each lens 13, 14, 15, 16, and 17 is aligned along a single optical axis O, forming a lens group L used for imaging. In this case, the first lens 13, located closest to the object, is a spherical glass lens having a convex surface on the object side and a concave surface 13c on the image side, while the other lenses 14, 15, 16, and 17 are resin lenses, but are not limited to these (for example, the first lens 13 may be a resin lens; if the first and second lenses 13 and 14 are made of resin, for example, the difference in their coefficients of thermal expansion is 40 × 10⁻⁶). -6 (It may be greater than or equal to / K(m)).

[0027] In this embodiment, the number of lenses, the materials of the lenses and lens barrel, etc., can be arbitrarily set according to 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 is not necessary. The surfaces of these lenses 13, 14, 15, 16, and 17 may be coated with an anti-reflective coating, a hydrophilic coating, a water-repellent coating, etc., as needed.

[0028] Inside the lens barrel 12, a cylindrical inner wall 12b is provided on the object side. The leading edge (upper end surface) of this inner wall 12b is a flat surface 12c perpendicular to the axial direction of the lens barrel 12. This flat surface 12c and the image-side end surface 13a of the first lens 13 are bonded together with a low-moisture-permeability adhesive ad for waterproofing. Furthermore, unlike conventional designs, this embodiment does not include an O-ring inside the lens barrel.

[0029] Furthermore, with the lens group L assembled and housed within its inner housing space S, the lens barrel 12 has a crimping portion 23 at its object-side end (upper end in Figure 1) that is thermally crimped radially inward. This crimping portion 23 fixes the first lens 13, which is located closest to the object in the lens group L, to the object-side end of the lens barrel 12 in the optical axis direction. In this case, to ensure stable crimping, the portion of the glass lens 13 to which the crimping portion 23 is pressed is formed as a flat portion 13b that is cut diagonally in a planar shape.

[0030] Furthermore, an inner flange portion 24 having an opening smaller in diameter than the fifth lens 17 is provided at the image-side end (lower end in Figure 1) of the lens barrel 12. The multiple lenses 13, 14, 15, 16, 17 that constitute the lens group L and the aperture members 22a, 22b are held and fixed in the optical axis direction within the lens barrel 12 by this inner flange portion 24 and the crimping portion 23.

[0031] The inner diameter of the lens barrel 12 decreases in stages from the object side towards the image plane side. Correspondingly, the outer diameters of the lenses 13, 14, 15, 16, and 17 decrease as they move from the object side towards the image plane side. Basically, the outer diameters of each lens 13, 14, 15, 16, and 17 are approximately equal to the inner diameters of the parts of the lens barrel 12 that support each of these lenses. Furthermore, an outer flange portion 25, used when mounting the lens barrel 12 to an in-vehicle camera, is provided on the outer surface of the lens barrel 12 in a flange-like manner.

[0032] Figure 2 is a schematic cross-sectional view of the camera module 300 of this embodiment, which has the lens unit 11 shown in Figure 1. As shown, the camera module 300 is configured to include the lens unit 11 to which the filter 105 is attached.

[0033] The camera module 300 comprises an outer casing (upper case, camera case) 301 and a mount (base) 302 that holds the lens unit 11. The camera module 300 also includes a sealing member 303 and a package sensor (image sensor) 304.

[0034] The upper case 301 is a component that exposes the object-side end of the lens unit 11 while covering the other parts. The mount 302 is located inside the upper case 301 and has a female thread 302a that screws into the male thread 11a of the lens unit 11. The sealing member 303 is a component interposed between the inner surface of the upper case 301 and the outer surface of the lens barrel 12 of the lens unit 11, and is a component that maintains airtightness inside the upper case 301.

[0035] The package sensor 304 is located inside the mount 302 and is positioned to receive the image of the object formed by the lens unit 11. The package sensor 304 is equipped with a CCD or CMOS sensor and converts the light that is focused and reaches it through the lens unit 11 into an electrical signal. The converted electrical signal is then converted into analog or digital data, which are components of the image data captured by the camera. The filter 105 is bonded to the lower surface of the inner flange portion 24 with a low-permeability adhesive ad.

[0036] In the lens unit 11 and camera module 300 having the above configuration, the first lens 13 located closest to the object and the lens barrel 12 are bonded and waterproofed with a low-moisture-permeability adhesive ad. Specifically, as shown in Figure 1(a), the outer surface of the first lens 13 and the inner surface of the lens barrel 12 are bonded and waterproofed with a low-moisture-permeable adhesive ad. In this embodiment, a filling portion 30 filled with the low-moisture-permeable adhesive ad is provided on the inner surface of the lens barrel 12, extending in the circumferential direction. The filling portion 30 is formed by cutting out a ring groove with a rectangular cross-section from the inner surface of the lens barrel 12, extending in the axial direction of the lens barrel 12, and having a bottom surface 30a at the image-side end. Such a filling portion 30 is formed on the inner surface of the lens barrel 12 before the crimping portion 23 is crimped (indicated by a dashed line in Figure 1). Then, before crimping the crimping portion 23, the filling portion 30 is filled with a low-moisture-permeable adhesive ad, and after filling, the crimping portion 23 is crimped. As a result, the outer surface of the first lens 13 and the inner surface of the lens barrel 12 are bonded and waterproofed by the low-moisture-permeable adhesive ad (hereinafter sometimes referred to as axial low-moisture-permeable adhesive ad). When filling the filling section 30 with a low-permeability adhesive ad, the adhesive ad is filled from the upper opening of the filling section 30. However, since the filling section 30 has a bottom surface 30a at its lower end, the low-permeability adhesive ad being filled stops flowing down at the bottom surface 30a. Therefore, it is possible to prevent the low-permeability adhesive ad from exceeding the outer surface of the first lens 13 or the inner surface of the lens barrel 12 and entering the lens barrel 12.

[0037] Furthermore, although only one filling portion 30 is formed in this embodiment, multiple axially low moisture permeability adhesive ad may be provided at predetermined intervals in the axial direction of the lens barrel 12. Furthermore, if the outer surface of the first lens 13 can be bonded and fixed to the inner surface of the lens barrel 12 with a predetermined axial adhesive strength using an axially low moisture permeability adhesive ad, the crimping portion 23 may be omitted.

[0038] As an alternative modification, as shown in Figure 2(b), a filling portion 31 filled with a low-moisture-permeability adhesive ad may be extended circumferentially on the outer surface of the first lens 13. Such a filling portion 31 also has a bottom surface 31a on the image side. In this alternative modification, there is no crimping portion 23, and the first lens 13 is fixed to the lens barrel 12 by an axially low-moisture-permeability adhesive ad. However, a crimping portion 23 may be provided, and the first lens 13 may be fixed by this crimping portion 23.

[0039] Furthermore, in this embodiment, as described above, the image-side end face 13a of the first lens 13 and the flat surface 12c of the lens barrel 12 that is perpendicular (intersects) with the axial direction are bonded and waterproofed with a low-moisture-permeability adhesive ad (hereinafter sometimes referred to as radially low-moisture-permeability adhesive ad). The flat surface 12c faces the image-side end face 13a of the first lens 13 and is positioned near the outer circumference of the end face 13a. Before assembling the first lens 13 into the lens barrel 12, a low-moisture-permeability adhesive ad is applied to the flat surface 12c, and then the first lens 13 is assembled into the lens barrel 12. This ensures that the image-side end face 13a of the first lens 13 and the flat surface 12c of the lens barrel 12 are bonded and waterproofed by the radially low-moisture-permeability adhesive ad.

[0040] Furthermore, in this embodiment, the axially low moisture permeability adhesive ad and the radially low moisture permeability adhesive ad were provided spaced apart, but they may also be provided continuously to form an L-shape in cross-section.

[0041] Examples of the low-permeability adhesive include acrylic adhesives, epoxy adhesives, and olefin adhesives, and the viscosity of these adhesives is preferably 10 Pa·s or higher. If the viscosity is less than 10 Pa·s, the axially low-permeability adhesive ad tends to drip downwards (towards the image side), making it difficult to assemble the first lens 13 into the lens barrel while ensuring waterproofing between its outer surface and the inner surface of the lens barrel 12.

[0042] Epoxy adhesives have higher adhesive strength than acrylic adhesives, but they have inferior impact resistance. Therefore, when the lens unit 11 is subjected to a thermal shock test, the epoxy adhesive may peel off. For this reason, it is preferable to use an acrylic adhesive, which has superior impact resistance than epoxy adhesives, but this may result in insufficient adhesive strength. Therefore, when using an acrylic adhesive as an axially low moisture permeable adhesive ad, it is preferable to roughen the inner surface of the lens barrel 12 and / or the outer surface of the first lens 13 by roughening means such as sandblasting. In this case, it is preferable to make the mean square surface roughness Rq to about 0.01 μm to 200 μm. Furthermore, when using an acrylic adhesive as a radially low moisture permeability adhesive ad, it is also preferable to roughen the flat surface 12c of the lens barrel 12 and / or the image-side end face 13a of the first lens 13. Furthermore, when using an acrylic adhesive as a low-moisture-permeability adhesive (ad), it is preferable to use a large bonding area to ensure adhesive strength.

[0043] Since metal telescope tubes 12 have better adhesive properties than resin telescope tubes 12, it may not be necessary to roughen the inner surface or flat surface 12c of the metal telescope tube 12. However, roughening the surface improves the adhesion of the low-moisture-permeable adhesive ad, so it is preferable. Furthermore, since epoxy adhesives have higher adhesive strength than acrylic adhesives, epoxy adhesives may be used as radially low moisture permeability adhesives (ad). This has the advantage of preventing misalignment of the optical axis of the first lens 13. Furthermore, since epoxy adhesives are harder than acrylic adhesives, using epoxy adhesive as an axially low moisture permeable adhesive (ad) is prone to causing misalignment of the optical axis of the first lens 13. However, by using acrylic adhesive as an axially low moisture permeable adhesive (ad), misalignment of the optical axis of the first lens 13 can be prevented.

[0044] Furthermore, in this embodiment, the low-moisture-permeable adhesive ad preferably has an elastic modulus of 1 to 1000 MPa and a Tg of 40°C to 60°C. The modulus of elasticity indicates the ease with which moisture can pass through the low-permeability adhesive ad. When the modulus of elasticity is less than 1 MPa, the flexibility of the low-permeability adhesive ad increases, making it easier for moisture to pass through. On the other hand, when it exceeds 1000 MPa, the low-permeability adhesive ad becomes too rigid, making the first lens 13 prone to breakage. For this reason, it is preferable to set the modulus of elasticity of the low-permeability adhesive ad to be between 1 and 1000 MPa. Tg is the glass transition temperature of the low-permeability adhesive. If Tg exceeds 60°C, the low-permeability adhesive becomes too hard, making the first lens prone to breakage. Conversely, if Tg is below 40°C, the low-permeability adhesive becomes too soft, allowing moisture to pass through easily (reducing waterproofing). Therefore, it is preferable to set Tg between 40°C and 60°C.

[0045] As described above, according to this embodiment, the first lens 13 located closest to the object and the lens barrel 12 are bonded and waterproofed with a low-moisture-permeability adhesive ad. Therefore, even without using an O-ring, moisture is less likely to enter the space on the back surface of the first lens, even in a high-humidity environment. Consequently, even when the outside temperature drops, fogging due to condensation on the back surface of the first lens 13 can be prevented. Furthermore, since O-rings are not used, the number of parts does not increase, and there is no hassle in installing O-rings.

[0046] Furthermore, since the outer surface of the first lens 13 and the inner surface of the lens barrel 12 are bonded and waterproofed with an axially low moisture permeability adhesive ad, moisture flowing from the object-side surface of the first lens 13 to the outer surface can be more reliably waterproofed. Furthermore, since filling sections 30 and 31 are provided extending circumferentially on either the outer surface of the first lens 13 or the inner surface of the lens barrel 12, the low-moisture-permeable adhesive ad can be reliably filled between the outer surface of the first lens 13 and the inner surface of the lens barrel 12 to provide waterproofing. In addition, since the filling sections 30 and 31 have bottom surfaces 30a and 31a at their lower ends, the low-moisture-permeable adhesive ad that is filled will stop flowing down at the bottom surfaces 30a and 31a. Therefore, it is possible to prevent the low-moisture-permeable adhesive ad from exceeding the outer surface of the first lens 13 or the inner surface of the lens barrel 12 and entering the lens barrel 12. Furthermore, since the image-side end face 13a of the first lens 13 and the flat surface 12c of the lens barrel 12 perpendicular to the axial direction are bonded and waterproofed with a radially low moisture permeability adhesive ad, even if the axially low moisture permeability adhesive ad that waterproofs the space between the outer surface of the first lens 13 and the inner surface of the lens barrel 12 is damaged by impact or the like and moisture enters the lens barrel, it is possible to reliably waterproof the space on the back surface of the first lens from entering. Furthermore, since the low-breathability adhesive ad is present both in the axial direction of the lens barrel 12 and in the radial direction intersecting the axial direction, when the lens unit 11 is subjected to impact, it becomes less likely that either of the low-breathability adhesive ad will be damaged, thus providing good resistance to impact.

[0047] Furthermore, since the low-permeability adhesive ad has an elastic modulus of 1 to 1000 MPa and a Tg of 40°C to 60°C, the first lens 13, which is located closest to the object, and the lens barrel 12 can be more reliably waterproofed by the low-permeability adhesive ad, and damage to the first lens 13 can be prevented.

[0048] In the embodiment described above, the case in which a resin lens barrel 12 is used was explained as an example, but as shown in Figures 3(a) and (b), a metal lens barrel 32 may also be used. In this metal lens barrel 32, as in the resin lens barrel 12, the first lens 33, second lens 34, third lens 35, fourth lens 36, and fifth lens 37 are incorporated from the object side (top side in Figure 3). Furthermore, the filter 105 is bonded to the lower surface of the inner flange portion 38 with a low-permeability adhesive ad.

[0049] When using a metal lens barrel 32, as shown in Figure 3(a), a filling portion 30 having a bottom surface 30a is provided on the inner circumferential surface of the lens barrel 32, extending in the circumferential direction. By filling this filling portion 30 with a low-moisture-permeability adhesive ad, the outer circumferential surface of the first lens 33 and the inner circumferential surface of the lens barrel 32 are bonded and waterproofed by the axially low-moisture-permeability adhesive ad. Furthermore, the image-side end face 33a of the first lens 33 and the flat surface 32c of the lens barrel 32 that is perpendicular (intersects) with the axial direction are bonded together with a radially low moisture permeability adhesive ad for waterproofing.

[0050] Furthermore, the first lens 33 is fixed to the object-side end (upper end) of the lens barrel 32 in the optical axis direction by screwing and tightening the cap (retaining member) 40 onto the object-side end (upper end) of the lens barrel 32. Furthermore, if the outer surface of the first lens 33 can be bonded and fixed to the inner surface of the lens barrel 32 with a predetermined axial adhesive strength using an axially low moisture permeability adhesive ad, the cap 40 may be omitted.

[0051] Furthermore, as shown in the modified example in Figure 3(b), a filling portion 31 filled with a low-moisture-permeability adhesive ad may be extended circumferentially on the outer surface of the first lens 33. Such a filling portion 31 also has a bottom surface 31a on the image side. By filling this filling portion 31 with the low-moisture-permeability adhesive ad, the outer surface of the first lens 33 and the inner surface of the lens barrel 32 are bonded and waterproofed by the axially low-moisture-permeability adhesive ad.

[0052] Furthermore, the image-side end face 33a of the first lens 33 and the flat surface 32c of the lens barrel 32 that is perpendicular (intersects) with the axial direction are bonded together with a radially low moisture permeability adhesive ad for waterproofing. In this modified example, if the outer surface of the first lens 33 can be bonded and fixed to the inner surface of the lens barrel 12 with a predetermined axial adhesive strength using an axially low moisture permeability adhesive ad, the cap 40 may be omitted.

[0053] It should be noted that the present invention is not limited to the embodiments described above, and can be implemented in various ways without departing from its spirit. For example, in the present invention, the shapes of lenses, lens barrels, etc., are not limited to the embodiments described above. Furthermore, some or all of the embodiments described above may be combined without departing from the spirit of the present invention, or some of the components of one of the embodiments described above may be omitted. [Explanation of Symbols]

[0054] 11 Lens Unit 12.32 Telescope Tube 12c, 32c Flat surface (surface intersecting the axial direction of the telescope tube) 13,33 First lens 13a, 33a Image-side end face of the first lens 14,15,16,17,34,35,36,37 lenses 30,31 Filling section ad Low breathability adhesive

Claims

1. In a lens unit comprising multiple lenses arranged along the optical axis and a lens barrel that houses and holds these multiple lenses, The plurality of lenses include a first lens located closest to the object, and the lens barrel has an inner cylindrical wall that protrudes toward the object in the optical axis direction from its inner opposing surface facing the image-side end face of the first lens. A lens unit characterized in that the outer surface of the first lens and the inner surface of the lens barrel are bonded and waterproofed together with a low-moisture-permeability adhesive along the optical axis direction, and the image-side end face of the first lens and the upper end face of the inner cylindrical wall intersecting the axial direction of the lens barrel are bonded and waterproofed together with the low-moisture-permeability adhesive, thereby defining a space toward the back surface of the first lens.

2. The lens unit according to claim 1, characterized in that a filling portion, in which the low-moisture-permeability adhesive is filled, is provided extending in the circumferential direction on either the outer surface of the first lens or the inner surface of the lens barrel.

3. A camera module characterized by comprising the lens unit described in claim 1 or 2.

Images