Lens unit

Abstract

To provide a lens unit and a camera unit which offer improved maintainability and serviceability as well as stabilized waterproof performance.SOLUTION: Disclosed herein are: a lens unit comprising a first lens, a cylindrical lens holder for holding the first lens, and an O-ring acting as a sealing member, where the first lens is fixed to the lens holder by fixing means using a screw structure, and the O-ring is sandwiched between the first lens and the lens holder in an optical axis direction; and a camera unit comprising the lens unit.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a lens unit and a camera unit including the same, and particularly relates to a technique for fixing a lens to a support such as a lens holder.

Background Art

[0002] Patent Document 1 listed below discloses a lens unit in which a lens is fixed to a lens holder by plastically deforming resin-made claws or protrusions via heating and pressurization.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When a lens is fixed by thermally deforming resin claws or the like on the lens holder as in the lens unit of Patent Document 1, breakage of the claws or the like is unavoidable to remove the lens after fixation. That is, the lens fixed to the lens holder cannot be replaced afterward.

[0005] Further, when the relevant lens is a lens that presses an O-ring in the optical axis direction, the lens may be lifted by the repulsive force of the O-ring before the thermally deformed claws or the like cool and solidify. This lifting reduces the crushing ratio of the O-ring, which may impair the waterproof performance of the lens unit.

[0006] In view of the above problems, the problem to be solved by the present invention is to improve the maintainability and serviceability of the lens unit and the camera unit, and to stabilize the waterproof performance thereof.

Means for Solving the Problems

[0007] To solve the above problems, the lens unit of the present invention comprises a first lens, a cylindrical lens holder for holding the first lens, and an O-ring as a sealing member, wherein the first lens is fixed to the lens holder by a fixing means using a screw structure, and the O-ring is sandwiched between the first lens and the lens holder in the optical axis direction.

[0008] By fixing the lens holder and the first lens with a screw-type fixing mechanism, it becomes possible to remove the first lens without damaging the lens holder, even after fixing. Furthermore, the lifting of the first lens due to the repulsive force of the O-ring is also prevented.

[0009] In this case, it is preferable that the first lens is a plastic lens, and the fixing means is composed of a male screw formed on the outer circumferential surface of the first lens and a female screw formed on the inner circumferential surface of the lens holder. By using a plastic lens, it is possible to form a male screw with high molding precision on the first lens itself, and the fixing means using a screw structure can be realized with a simple structure.

[0010] Furthermore, in this case, the first lens and the lens holder have, separately from the fixing means, an optical axis positioning part that abuts each other in the direction of the optical axis and determines the optical axis position of the first lens relative to the lens holder. When the direction perpendicular to the optical axis is called the radial direction, the first lens has a flange portion that is on the object side of the male screw and extends radially outward from the position of the male screw, and it is preferable that the optical axis positioning part is composed of the image side surface of the flange portion and the surface of the lens holder facing it. When fixing a lens using a fixing means with a screw structure, a certain amount of play (backlash) is necessary for the screw to screw in smoothly. This play can cause rattle of the lens in the optical axis direction and individual differences and disturbances in the lens position. By providing an optical axis positioning part separately from the screw structure, such problems can be suppressed and the optical quality of the lens unit can be stabilized.

[0011] Furthermore, in this case, the first lens and the lens holder have a radial positioning portion that abuts each other radially and determines the radial position of the first lens relative to the lens holder, separate from the fixing means, the first lens has a cylindrical or columnar fitting portion on the image side of the male screw, and the radial positioning portion is preferably composed of the outer circumferential surface of the fitting portion and the surface of the lens holder facing it. When fixing a lens using a fixing means with a screw structure, a certain amount of play (difference in effective diameter) is necessary for the screw to screw in smoothly. This play can cause rattling of the lens radially and individual differences and disturbances in the lens position. By providing a radial positioning portion separate from the screw structure, such problems can be suppressed and the optical quality of the lens unit can be stabilized. The first lens may have a cylindrical or columnar fitting portion on the object side of the male screw, and the radial positioning portion may be composed of the outer circumferential surface of the fitting portion and the surface of the lens holder facing it.

[0012] Furthermore, it is preferable that the outer circumferential surface of the fitting portion be positioned radially outward from the position of the O-ring. The male thread of the first lens is screwed into the inner circumferential surface of the lens holder, and is therefore usually positioned radially outward from the O-ring. For the purpose of eliminating the problems caused by play in the screw structure, it is more convenient for the fitting portion to be provided continuously with the male thread, that is, positioned radially outward from the position of the O-ring. In addition, by doing so, a radial positioning portion can be provided by machining a part of the forming surface of the male thread, and the structural complexity caused by providing a radial positioning portion is reduced.

[0013] Furthermore, the lens unit of the present invention may be a plastic lens having a cylindrical portion as the first lens, and the fixing means may be composed of a male screw formed on the outer circumferential surface of the lens holder and a female screw formed on the inner circumferential surface of the cylindrical portion. The effect of providing a screw structure to the first lens itself by using a plastic lens is as described above.

[0014] In this case, the first lens and the lens holder preferably have an optical axis positioning portion separate from the fixing means, an annular groove is formed on the image side surface of the first lens, the female screw is formed on the radially outer wall surface of the groove, and the optical axis positioning portion is preferably composed of the bottom surface of the groove and the surface of the lens holder opposite it. The effects of providing the optical axis positioning portion separately from the screw structure are as described above.

[0015] Furthermore, it is preferable that the first lens and the lens holder have a radial positioning portion separate from the fixing means, and that the radial positioning portion is composed of the radially inner wall surface of the groove portion and the surface of the lens holder facing it. The effects of providing the radial positioning portion separately from the screw structure are as described above.

[0016] Furthermore, it is preferable that the lens unit of the present invention has recesses, protrusions, notches, knurling, serrations, splines, or other irregularities on the outer surface of the first lens that do not affect its optical performance, which create circumferential engagement with jigs, tools, or fingers. This facilitates the replacement of the first lens. In particular, when the lens unit is extremely small or extremely large, and it is difficult to rotate the first lens without using some kind of tool, the purpose of replacing the first lens is achieved only with such irregularities.

[0017] Furthermore, the lens unit of the present invention has a first lens having a lens portion that determines its optical performance and a non-lens portion that extends radially outward from the lens portion, with a plurality of holes formed in the non-lens portion, and the first lens may be fixed to the lens holder by passing screws through the holes in the non-lens portion. The effects of fixing the lens holder and the first lens with a fixing means using a screw structure are as described above. In addition, the holes in the non-lens portion may be holes without screw grooves (so-called oversized holes or drilled holes), and the invention can also be applied to glass lenses in which it is difficult to form screws.

[0018] In this case, the first lens and the lens holder preferably have an optical axis positioning portion separate from the fixing means, and the optical axis positioning portion is preferably composed of the image side surface of the non-lens portion and the surface of the lens holder facing it. The effects of providing the optical axis positioning portion separately from the screw structure are as described above.

[0019] Furthermore, in this case, the first lens and the lens holder preferably have a radial positioning portion separate from the fixing means, the first lens has a cylindrical or columnar fitting portion positioned radially inward from the O-ring, and the radial positioning portion is preferably composed of the outer circumferential surface of the fitting portion and the surface of the lens holder facing it. The effects of providing the radial positioning portion separately from the screw structure are as described above.

[0020] Thus, the lens unit of the present invention preferably has an optical axis positioning portion that, separately from the fixing means, contacts the first lens and the lens holder in the optical axis direction and determines the optical axis position of the first lens relative to the lens holder, and also preferably has a radial positioning portion that, separately from the fixing means, contacts the first lens radially and determines the radial position of the first lens relative to the lens holder.

[0021] Furthermore, in the lens unit of the present invention, the first lens and the lens holder may be joined together with an adhesive. By joining them with an adhesive in addition to the fixing means using a screw structure, it is possible to prevent the screws from loosening after fixing.

[0022] In this case, it is preferable that the adhesive is a disassemblable adhesive that can be released after bonding by applying a specific treatment to the joint. This makes it possible to achieve both prevention of screw loosening and ease of replacement of the first lens.

[0023] Further, the lens unit of the present invention includes a plurality of lenses arranged along the optical axis direction, wherein the first lens is the lens disposed closest to the object side among the plurality of lenses, and a lens disposed on the image side relative to the first lens is preferably caulked and fixed to the lens holder. By selecting the optimal fixing method according to the properties of individual lenses and the usage environment, it is possible to improve the optical quality, maintainability, serviceability, assemblability, cost efficiency and the like of the lens unit in a well-balanced manner.

[0024] Further, to solve the above problems, a camera unit of the present invention includes a plurality of lenses arranged along the optical axis direction, a cylindrical lens holder, an O-ring which is a sealing member, a camera module, and a camera case that accommodates the camera module, wherein when the lens closest to the object side among the plurality of lenses is referred to as a first lens, the lens holder holds the lens disposed on the image side relative to the first lens, the first lens has a lens portion that defines its optical performance, and a non-lens portion that extends radially outward from the lens portion, a plurality of holes are formed in the non-lens portion, the first lens is fixed to the object-side surface of the camera case by passing screws through the holes in the non-lens portion, and the O-ring is sandwiched in the optical axis direction between the first lens and the camera case or the lens holder, which is the gist of the present invention.

[0025] The effects obtained by fixing the first lens with the fixing means using a screw structure are as described above. In addition, the effects obtained by screwing and fixing the non-lens portion of the first lens are also as described above. Here, in order to fix the non-lens portion of the first lens with screws, a certain area is required for the non-lens portion. That is, a disadvantage of increasing the size of the unit may occur. In the present invention, the first lens is directly fixed to the camera case instead of the lens holder, whereby the disadvantage can be reduced while obtaining the effect of the fixing means using a screw structure. Advantageous Effects of Invention

[0026] As described above, according to the present invention, the maintainability and serviceability of the lens unit and the camera unit are improved, and the waterproof performance thereof is stabilized. Brief Description of the Drawings

[0027] [Figure 1] It is a side cross-sectional view showing the internal structure of the lens unit according to the first embodiment. [Figure 2] It is an enlarged view of the part enclosed by the one-dot chain line in Figure 1. [Figure 3] It is a perspective view showing the structure of the notch portion of the first lens. [Figure 4] It is a partially enlarged view showing a modification of the lens unit according to the first embodiment. [Figure 5] It is a side cross-sectional view showing the internal structure of the lens unit according to the second embodiment. [Figure 6] It is an enlarged view of the part enclosed by the one-dot chain line in Figure 5. [Figure 7] It is a side cross-sectional view showing the internal structure of the camera unit according to the third embodiment. [Figure 8] It is an enlarged view of the part enclosed by the one-dot chain line in Figure 7. [Figure 9] It is a plan view of the camera unit. [Figure 10] It is a side cross-sectional view (a) and a side view (b) showing the internal structure of the lens unit according to the fourth embodiment. [Figure 11] It is a side view showing a modification of the lens unit according to the fourth embodiment. Modes for Carrying Out the Invention

[0028] Hereinafter, embodiments of the lens unit and the camera unit of the present invention will be described with reference to the drawings.

[0029] The lens unit and camera unit described below are characterized by their method of fixing the lens, particularly the lens positioned closest to the object. Specifically, by employing a fixing means using a screw structure or a fixing means using an elastically deformable arm and hook, the lens can be removed after fixing, and furthermore, displacement of the lens due to the repulsive force of the O-ring is prevented. These features and their incidental features will be described below based on various embodiments.

[0030] <First Embodiment> (Overall structure) The lens unit U1 in this embodiment is a general-purpose, compact lens unit that can be used in various photographic devices. Figure 1 is a side cross-sectional view showing the internal structure of the lens unit U1 according to the first embodiment. The overall configuration of the lens unit U1 will be described below with reference to Figure 1.

[0031] The dashed line L1-L2 in Figure 1 indicates the optical axis of lens unit U1, with L1 being the object side (subject side) and L2 being the image side. For the sake of explanation following the diagram, L1 may be referred to as "up" and L2 as "down." The direction perpendicular to the optical axis is called the "radial direction," and for convenience, this may be referred to as "horizontal." In the following explanation, "circumferential direction" refers to the direction around the optical axis.

[0032] The lens unit U1 has five lenses, the first to fifth lenses 10 to 95, arranged along the optical axis L1-L2, and a lens holder 20 that holds these lenses. A light-shielding plate 97 is positioned between the second lens 92 and the third lens 93, and an aperture 98 is positioned between the third lens 93 and the fourth lens 94. An optical filter 96 is positioned on the image-side end face of the lens holder 20, and the optical filter 96 is crimped and fixed to the end face of the lens holder 20 by a resin claw portion 961. The second lens 92 is crimped and fixed to the lens holder 20 by a resin annular rib 921 provided on the lens holder 20.

[0033] All lenses in this configuration are plastic lenses, and the fifth lens 95 and the fourth lens 94, located closest to the image sensor, form a cemented lens. The number and types of lenses held in the lens holder 20 are not limited to this configuration and can be changed as appropriate depending on the application of the lens unit and the subject.

[0034] The lens holder 20 is a lens barrel / frame that holds these lenses, and has a cylindrical small-diameter section 21 and a large-diameter section 22 having a larger inner diameter than the small-diameter section 21. The large-diameter section 22 and the small-diameter section 21 are connected by an annular planar section that extends horizontally from the upper end of the small-diameter section 21. The first lens 10 is held in the large-diameter section 22, while the second lenses 92 to the fifth lenses 95, the light-shielding plate 97, and the aperture 98 are held in the small-diameter section 21. The structure of the lens holder 20 is not limited to this embodiment, and any lens holder structure that includes a screw structure or hook structure, as will be described later, may be used.

[0035] An O-ring 91 is placed on the flat surface connecting the small-diameter portion 21 and the large-diameter portion 22 of the lens holder 20. The O-ring 91 is a sealing member that prevents water from entering the lens unit U1 from the object side. The O-ring 91 is sandwiched between the flat surface on which it is placed and the lower surface of the first lens 10, and is compressed in the direction of the optical axis.

[0036] (Fixing structure of the first lens) Figure 2 is an enlarged view of the area enclosed by the dashed line in Figure 1, and shows the details of the fixing structure of the first lens 10. The fixing structure of the first lens 10 in this embodiment will be described below with reference to Figure 2.

[0037] The first lens 10 is a plastic lens with negative power. The first lens 10 has a male thread 111 engraved on the outer surface of its body 11 (see Figure 1). Above the male thread 111, there is an annular flange portion 12 that protrudes radially outward from the male thread 111. Below the male thread 111, there is a lens-side fitting portion 13a, which is a cylindrical fitting portion that protrudes downward.

[0038] The large-diameter portion 22 of the lens holder 20 is a cylindrical tube. The inner circumferential surface of the large-diameter portion 22 has a female thread 221 that corresponds to the male thread 111 of the first lens 10. Below the female thread 221, there is a holder-side fitting portion 23a, which is an inner circumferential surface that protrudes radially inward from the top of the thread of the female thread 221.

[0039] As shown in Figure 2, the first lens 10 is fixed to the lens holder 20 by a fixing means using a screw structure. Specifically, the first lens 10 is fixed to the lens holder 20 by screwing its male thread 111 into the female thread 221 of the lens holder 20. As mentioned above, the first lens 10 in this embodiment is a plastic lens. By using a plastic lens, it is possible to form a male thread 111 with high molding precision on the first lens 10 itself, and the fixing means using a screw structure can be realized with a simple structure. Furthermore, by fixing the lens holder 20 and the first lens 10 with screws, the first lens 10 can be removed without damaging the lens holder 20 even after it has been fixed. In addition, the lifting of the first lens 10 due to the repulsive force of the O-ring 91 is also prevented. Plastic lenses are cheaper than glass lenses, but they are less hard than glass lenses and are therefore more susceptible to scratches. With the lens unit U1, if the performance of the first lens 10 is impaired due to scratches, it can be easily replaced.

[0040] In this embodiment, the first lens 10 and lens holder 20, apart from the screw structure described above, have an optical axis positioning portion that contacts each other in the direction of the optical axis and determines the optical axis position of the first lens 10 relative to the lens holder 20. The optical axis positioning portion in this embodiment is composed of the lower surface 12a of the flange portion 12 of the first lens 10 and the upper surface 22a of the large diameter portion 22a that is opposite to it.

[0041] Furthermore, the first lens 10 and lens holder 20 in this embodiment have a radial positioning portion that abuts each other radially and determines the radial position of the first lens 10 relative to the lens holder 20, separate from the screw structure described above. The radial positioning portion in this embodiment is composed of the outer circumferential surface of the lens-side fitting portion 13a of the first lens 10 and the holder-side fitting portion 23a of the large-diameter portion 22 that is opposite to it.

[0042] When fixing a lens using a screw structure, a certain amount of play (backlash or difference in effective diameter) is necessary for the screw to engage smoothly. This play can cause looseness in the lens in the optical axis direction and radial direction, as well as individual differences and irregularities in lens position. In this embodiment, lens unit U1 is equipped with optical axis direction positioning parts and radial direction positioning parts in addition to the screw structure, thereby suppressing such problems and stabilizing the optical quality of lens unit U1.

[0043] Furthermore, as shown in Figure 1, in the lens unit U1, the first lens 10 and the lens holder 20 are also joined by adhesive 99. In addition to the fixing means using a screw structure, bonding them with adhesive 99 prevents the screws from loosening after fixing.

[0044] In this embodiment, the adhesive 99 is a thermoplastic adhesive, and the bond can be released by reheating the joint after bonding. This ensures both prevention of screw loosening and easy replacement of the first lens 10. The adhesive that can be used is not limited to thermoplastic adhesives; any adhesive that can be released by applying a specific treatment to the joint after bonding (a so-called disassemblable adhesive) is acceptable. Alternatively, an adhesive with sufficient bonding strength to prevent screw loosening may be used, and which can be peeled off without damaging the first lens 10 or lens holder 20 if attempted. This bonding method using adhesive 99 can also be used in the subsequent second to fourth embodiments.

[0045] (First lens replacement support structure) Figure 3 is a perspective view showing the structure of the notches 14 of the first lens 10. As shown in Figure 3, the first lens 10 has three notches 14 provided at equal intervals in the circumferential direction on the outer edge of its flange portion 12.

[0046] As mentioned above, the lens unit U1 in this configuration is a small lens unit, with a diameter of approximately 15-16 mm. With small lens units like the lens unit U1, or conversely, with very large lens units, it can be difficult to replace the first lens 10 by hand. The lens unit U1 has a notch 14 on the first lens 10, which allows the first lens 10 to be easily and safely replaced using a special tool. The shape and structure of the notch 14 are not limited to the configuration of the lens unit U1. The notch 14 can be any recess, protrusion, knurling, serration, spline, or other irregularity that creates circumferential engagement with a jig, tool, or finger, and is provided in a part that does not affect the optical performance of the lens. If it is difficult to rotate the first lens 10 without using some kind of tool, then such irregularities are necessary to achieve the purpose of replacing the first lens 10.

[0047] (modified version) Figure 4 is a partially enlarged view showing a modified version of the lens unit U1. The modifications described below mainly concern the lens-side fitting portion 13a and the holder-side fitting portion 23a, which constitute the radial positioning portion of the lens unit U1.

[0048] As shown in Figure 2, the lens-side fitting portion 13a in the above embodiment is a cylindrical portion that protrudes further downward from the lower end of the body portion 11 (see Figure 1) of the first lens 10. In the modified example shown in Figure 4(a), the outer diameter of the lower end of the body portion 11 is made smaller than the diameter of the bottom of the screw groove of the male screw 111, thereby providing the lens-side fitting portion 13b on the body portion 11 itself. On the other hand, the lens holder 20 side is almost the same as the holder-side fitting portion 23a in the above embodiment, and a holder-side fitting portion 23b is provided below the female screw 221, protruding radially inward from the top of the screw thread of the female screw 221.

[0049] In the modified example shown in Figure 4(b), the outer diameter of the upper end of the body portion 11 is made larger than the diameter of the top of the thread of the male screw 111, thereby providing the body portion 11 itself with a lens-side fitting portion 13c. The lens holder 20 is provided with a holder-side fitting portion 23c on top of the female screw 221, which is an inner circumferential surface that extends radially outward from the bottom of the thread groove of the female screw 221.

[0050] In both the above embodiment and the above modification, the outer circumferential surfaces of the lens-side fitting portions 13a, 13b, and 13c are positioned radially outward from the position of the O-ring 91. The male thread 111 of the first lens 10 is screwed into the inner circumferential surface of the lens holder 20, and is therefore usually positioned radially outward from the O-ring 91. For the purpose of eliminating the problems caused by play in the screw structure, it is preferable for the lens-side fitting portions 13a, 13b, and 13c to be provided continuously with the male thread 111, that is, positioned radially outward from the position of the O-ring 91. Furthermore, by doing so, a radial positioning portion can be provided by machining a part of the forming surface of the male thread 111 (i.e., the outer circumferential surface of the body portion 11), thereby reducing the structural complexity caused by providing a radial positioning portion.

[0051] <Second Embodiment> Figure 5 is a side cross-sectional view showing the internal structure of the lens unit U2 according to the second embodiment. Figure 6 is an enlarged view of the area enclosed by the dashed line in Figure 5, showing the details of the fixing structure of the first lens 15. The features of the lens unit U2 will be described below with reference to Figures 5 and 6. In the following description, components identical to those in the first embodiment will be given the same reference numerals as in the previous embodiment, and their detailed descriptions will be omitted. Also, components with the same names as those in the first embodiment may be considered to be components corresponding to those in the first embodiment. The same applies to the descriptions of the third embodiment and subsequent embodiments.

[0052] In the lens unit U1 of the first embodiment, the first lens 10 was provided with a male screw 111 and the lens holder 20 was provided with a female screw 221. However, in the lens unit U2 of this embodiment, the opposite is true: the first lens 15 is provided with a female screw 17 and the lens holder 25 is provided with a male screw 28.

[0053] The first lens 15 has an annular groove 16 formed on its lower surface. The groove 16 is composed of a bottom surface 16a, an outer wall surface 16b which is the radially outer wall surface, and an inner wall surface 16c which is the radially inner wall surface. The female thread 17 is formed on the outer wall surface 16b of the groove 16, and the male thread 28 is formed on the outer circumferential surface 27b of the large diameter portion 27 of the lens holder 25. The effect of providing a thread structure on the first lens itself by using a plastic lens is as described in the first embodiment. In addition, the lens unit U2 may also have a notch 14 similar to that of the lens unit U1.

[0054] The optical axis positioning portion of the lens unit U2 is composed of the bottom surface 16a of the groove 16 and the upper surface 27a of the large diameter portion 27 that is opposite it. The radial positioning portion of the lens unit U2 is composed of the inner wall surface 16c of the groove 16 and the inner circumferential surface 27c of the large diameter portion 27 that is opposite it. The effects of providing the optical axis positioning portion and radial positioning portion separately from the screw structure are as described in the first embodiment.

[0055] In this embodiment, a groove 16 is used to provide a radial positioning section by utilizing the inner circumferential surface 27c of the large-diameter section 27. However, if a radial positioning section is not required, or if it is provided in a different way than in this embodiment, instead of a groove 16, a simple cylindrical section (corresponding to the outer circumferential surface of the first lens 15 and the inner wall surface 16b of the groove 16) may be provided on the first lens 15, and a female thread 17 may be formed on its inner circumferential surface.

[0056] <Third Embodiment> Figure 7 is a side cross-sectional view showing the internal structure of the camera unit U3 according to the third embodiment. Figure 8 is an enlarged view of the area enclosed by the dashed line in Figure 7, showing the details of the fixing structure of the first lens 30. Figure 9 is a plan view of the camera unit U3. The features of the camera unit U3 will be described below with reference to Figures 7 to 9.

[0057] Camera unit U3 is a small camera unit primarily used as an in-vehicle camera. Camera unit U3 incorporates a camera module 46 and has a cylindrical lens holder section 45 that holds second lenses 92 to fifth lenses 95, a light shield plate 97, an aperture 98, and an optical filter 96. These are housed in a camera case 40, which is the case for camera unit U3.

[0058] The first lens 30 of the camera unit U3 is a plastic lens. The first lens 30 has a lens portion 31 that determines its optical performance, and a non-lens portion 32 that extends radially outward from the body portion 311 (see Figure 7) of the lens portion 31. As shown in Figure 9, the planar shape of the non-lens portion 32 is a rounded rectangle, and its four corners are fastened with screws 49. As shown in Figure 8, the first lens 30 is fixed to the upper surface of the camera case 40 by inserting the screws 49 into the holes 321 of the non-lens portion 32 and fastening them to the screw holes 41 of the camera case 40. The holes 321 of the non-lens portion 32 are holes without screw threads (so-called oversized holes or drilled holes). Therefore, the first lens 30 may also be a glass lens. The O-ring 91 is sandwiched between the lower surface 32a of the non-lens portion 32 and the upper surface of the camera case 40 (the O-ring mounting surface 43 described later), and is compressed in the direction of the optical axis. The effect of fixing the first lens 30 to the camera case 40 using a screw structure is as described in the first embodiment.

[0059] As shown in Figure 8, the upper surface of the camera case 40 is formed such that the surface level decreases in a stepped manner from its outer edge toward the center (lens holder portion 45). On the upper surface of the camera case 40, from the outer edge toward the center, the following surfaces are formed in order: a lens mounting surface 42 whose surface level is recessed in the same shape as the first lens 30 (non-lens portion 32), an O-ring mounting surface 43 on which the O-ring 91 is placed, and the upper surface 45a of the lens holder portion 45.

[0060] As shown in Figure 8, the optical axis positioning portion of the camera unit U3 is composed of the lower surface 32a of the non-lens portion 32 and the lens mounting surface 42 of the camera case 40, which is opposite to it. The radial positioning portion of the camera unit U3 is composed of the lens-side fitting portion 33 of the first lens 30 and the case-side fitting portion 44 of the camera case 40, which is opposite to it. The lens-side fitting portion 33 is the outer circumferential surface of the body portion 311 (see Figure 7) of the first lens 30. The case-side fitting portion 44 is the vertical surface between the O-ring mounting surface 43 and the upper surface 45a of the lens holder. The effect of providing the optical axis positioning portion and radial positioning portion separately from the screw structure is as described in the first embodiment.

[0061] In this case, to fix the non-lens portion 32 of the first lens 30 with a screw 49, a certain amount of surface area is required for the non-lens portion 32. This can lead to the drawback of increasing the size of the unit. In the camera unit U3, the first lens 30 is fixed directly to the camera case 40 instead of the lens holder portion 45, thereby achieving the effect of a fixing means using a screw structure while mitigating this drawback. If increasing the size of the unit does not occur or is not a problem, the lens holder portion 45 may be made larger and the first lens 30 may be screw-fixed to the lens holder portion 45.

[0062] <Fourth Embodiment> Figure 10 shows a side view cross-sectional view (a) and a side view (b) illustrating the internal structure of the lens unit U4 according to the fourth embodiment. The features of the lens unit U4 will be described below with reference to Figure 10.

[0063] In the embodiments described above, a configuration was described in which the first lens is fixed to a lens holder or camera case by a fixing means using a screw structure. However, fixing means that allow the lens to be removed after fixing and prevent the lens from shifting position due to the repulsive force of the O-ring are not limited to fixing means using a screw structure. In the lens unit U4 described below, this problem is solved by using a fixing means that uses an elastically deformable arm and a hook instead of a screw structure.

[0064] The first lens 50 of the lens unit U4 is a plastic lens, and an annular groove 51 is formed on its lower surface. Multiple elastic arms 52 extend downward from the outer circumference of the first lens 50 (the part radially outside the groove 51). In this embodiment, three elastic arms 52 are arranged at equal intervals in the circumferential direction. A hook 521 is provided at the lower end of each elastic arm 52, and the hook 521 engages with the lower surface 62a of the large diameter portion 62 of the lens holder 60.

[0065] In the lens unit U4, the use of a plastic lens for the first lens 50 makes it possible to integrally mold the first lens 50 and the elastic arm 52. Furthermore, since the first lens 50 is fixed to the lens holder 60 by the hook 521 of the elastic arm 52, it can be removed without damaging the lens holder 60 even after the first lens 50 has been fixed. In addition, the lifting of the first lens 50 due to the repulsive force of the O-ring 91 is prevented. Moreover, if the performance of the first lens 50 is impaired due to damage, it can be easily and inexpensively replaced.

[0066] In the lens unit U4, the position of the first lens 50 in the optical axis direction is determined by the hook 521 of the elastic arm 52 and the lower surface 62a of the large diameter portion 62 (because the first lens 50 is always pushed upward toward the object due to the repulsive force of the O-ring 91). Furthermore, the radial position of the first lens 50 is determined by the inner wall surface 51c, which is the radially inner surface of the wall surface of the groove portion 51, and the inner circumferential surface 62b of the large diameter portion 62, which is opposite to it.

[0067] (modified version) Figure 11 is a side view showing a modified example of the lens unit U4. As shown in Figure 11, the elastic arm 52 and hook 521 may have a hook 63 on the lens holder 60 side, and a hole 531 for fitting and engaging with the hook may be provided in the elastic arm 52.

[0068] <Other> Furthermore, this technology can be configured as follows: (1) The first lens is a lens, A cylindrical lens holder that holds the first lens, It comprises an O-ring which is a sealing member, The first lens is fixed to the lens holder by a fixing means using a screw structure. The O-ring is sandwiched between the first lens and the lens holder in the optical axis direction. Lens unit. (2) The first lens is a plastic lens, The fixing means is composed of a male screw formed on the outer circumferential surface of the first lens and a female screw formed on the inner circumferential surface of the lens holder. (1) The lens unit described above. (3) The first lens and the lens holder, apart from the fixing means, have an optical axis positioning portion that contacts each other in the optical axis direction and determines the optical axis position of the first lens relative to the lens holder. When we refer to the direction perpendicular to the optical axis as the radial direction, The first lens has a flange portion that is on the object side of the male screw and extends radially outward from the position of the male screw, The optical axis positioning portion is composed of the image surface of the flange portion and the surface of the lens holder opposite it. (2) The lens unit described above. (4) When we refer to the direction perpendicular to the optical axis as the radial direction, The first lens and the lens holder, apart from the fixing means, have radial positioning parts that contact each other radially and determine the radial position of the first lens relative to the lens holder. The first lens has a cylindrical or columnar fitting portion on the image side of the male screw, The radial positioning portion is composed of the outer circumferential surface of the fitting portion and the surface of the lens holder facing it. The lens unit as described in (2) or (3). (5) When we refer to the direction perpendicular to the optical axis as the radial direction, The first lens and the lens holder, apart from the fixing means, have radial positioning parts that contact each other radially and determine the radial position of the first lens relative to the lens holder. The first lens has a cylindrical or columnar fitting portion on the object side of the male screw, The radial positioning portion is composed of the outer circumferential surface of the fitting portion and the surface of the lens holder facing it. The lens unit as described in (2) or (3). (6) The outer circumferential surface of the fitting portion is positioned radially outward from the position of the O-ring. The lens unit as described in (4) or (5). (7) The first lens is a plastic lens having a cylindrical portion. The fixing means is composed of a male thread formed on the outer circumferential surface of the lens holder and a female thread formed on the inner circumferential surface of the cylindrical portion. (1) The lens unit described above. (8) The first lens and the lens holder, apart from the fixing means, have an optical axis positioning portion that contacts each other in the optical axis direction and determines the optical axis position of the first lens relative to the lens holder. An annular groove is formed on the image surface of the first lens. When we refer to the direction perpendicular to the optical axis as the radial direction, The female thread is formed on the radially outer wall surface of the groove portion, The optical axis direction positioning portion is composed of the bottom surface of the groove and the surface of the lens holder facing it. (7) The lens unit described above. (9) The first lens and the lens holder, apart from the fixing means, have radial positioning parts that contact each other radially and determine the radial position of the first lens relative to the lens holder. The radial positioning portion is composed of the radially inner wall surface of the groove portion and the surface of the lens holder facing it. (8) The lens unit described above. (10) The outer surface of the first lens is provided with recesses, protrusions, notches, knurling, serrations, splines, or other irregularities in areas not related to its optical performance that allow for circumferential engagement with jigs, tools, or fingers. A lens unit as described in any of (1) through (9). (11) When we refer to the direction perpendicular to the optical axis as the radial direction, The first lens is, The lens section determines its optical performance, It has a non-lens portion that extends radially outward from the lens portion, Multiple holes are formed in the non-lens portion. The first lens is fixed to the lens holder by passing a screw through the hole in the non-lens portion. (1) The lens unit described above. (12) The first lens and the lens holder, apart from the fixing means, have an optical axis positioning portion that contacts each other in the optical axis direction and determines the optical axis position of the first lens relative to the lens holder. The optical axis direction positioning portion is composed of the image surface of the non-lens portion and the surface of the lens holder opposite it. (11) The lens unit described above. (13) The first lens and the lens holder, apart from the fixing means, have radial positioning parts that contact each other radially and determine the radial position of the first lens relative to the lens holder. The first lens has a cylindrical or columnar fitting portion that is positioned radially inward from the O-ring, The radial positioning portion is composed of the outer circumferential surface of the fitting portion and the surface of the lens holder facing it. The lens unit as described in (11) or (12). (14) The first lens and the lens holder, apart from the fixing means, have an optical axis positioning portion that contacts each other in the optical axis direction and determines the optical axis position of the first lens relative to the lens holder. A lens unit as described in any of (1) to (13). (15) When we refer to the direction perpendicular to the optical axis as the radial direction, The first lens and the lens holder, apart from the fixing means, have radial positioning parts that contact each other radially and determine the radial position of the first lens relative to the lens holder. A lens unit as described in any of (1) to (14). (16) The first lens and the lens holder are joined together with adhesive. A lens unit as described in any of (1) to (15). (17) The aforementioned adhesive is a disassemblable adhesive that can be released after bonding by applying a specific treatment to the joint. The lens unit described in (16). (18) Equipped with multiple lenses arranged along the optical axis, The first lens is the lens among the plurality of lenses that is positioned closest to the object. The lens positioned closer to the image than the first lens is crimped and fixed to the lens holder. A lens unit as described in any of (1) through (17). (19) Multiple lenses arranged along the optical axis, A cylindrical lens holder, The O-ring is a sealing component, Camera module and The camera comprises a camera case for housing the aforementioned camera module, When referring to the lens closest to the object among the aforementioned multiple lenses as the first lens, The lens holder holds the lens which is positioned closer to the image than the first lens. When we refer to the direction perpendicular to the optical axis as the radial direction, The first lens is, The lens section determines its optical performance, It has a non-lens portion that extends radially outward from the lens portion, Multiple holes are formed in the non-lens portion. The first lens is fixed to the object-side surface of the camera case by passing a screw through the hole in the non-lens portion. The O-ring is sandwiched in the optical axis direction between the first lens and the camera case or the lens holder. Camera unit.

[0069] Although embodiments of the present invention have been described in detail above, the present invention is not limited in any way to the above embodiments, and various modifications are possible without departing from the spirit of the present invention. [Explanation of Symbols]

[0070] U1: Lens unit, 10: First lens, 11: Body, 111: Male screw (fixing means), 12: Flange, 12a: Bottom surface (optical axis direction positioning part), 13a~13c: Lens side fitting part (radial direction positioning part), 14: Notch, 20: Lens holder, 21: Small diameter part, 22: Large diameter part, 221: Female screw (fixing means), 22a: Top surface (optical axis direction positioning part), 23a~23c: Holder side fitting part (radial direction positioning part), U2 :Lens unit, 15:First lens, 16:Groove, 16a:Bottom surface (radial positioning part), 16b:Outer wall surface, 16c:Inner wall surface (optical axis direction positioning part), 17:Female screw (fixing means), 25:Lens holder, 27:Large diameter part, 27a:Top surface (optical axis direction positioning part), 27b:Outer circumference surface, 27c:Inner circumference surface (radial positioning part), 28:Male screw (fixing means), U3:Camera unit, 30:First lens, 31:Lens part, 311: Body, 32: Non-lens part, 32a: Image side (optical axis direction positioning part), 321: Hole, 33: Lens side fitting part (radial direction positioning part), 40: Camera case, 41: Screw hole (fixing means), 42: Lens mounting surface (optical axis direction positioning part), 43: O-ring mounting surface, 44: Case side fitting part (radial direction positioning part), 45: Lens holder part, 45a: Top surface, 46: Camera module, 49: Screw (fixing means), U4: Lens unit 50: First lens, 51: Groove, 51c: Inner wall surface, 52: Elastic arm, 521: Hook, 531: Hook hole, 60: Lens holder, 61: Small diameter section, 62: Large diameter section, 62a: Bottom surface, 62b: Inner circumference surface, 63: Hook, 91: O-ring, 92: Second lens, 921: Crimped section, 93: Third lens, 94: Fourth lens, 95: Fifth lens, 96: Optical filter, 961: Crimped section, 97: Light shield, 98: Aperture, 99: Adhesive

Claims

1. Multiple lenses arranged along the optical axis, A cylindrical lens holder that holds the aforementioned multiple lenses, It comprises an O-ring which is a sealing member, The first lens, which is positioned closest to the object, is fixed to the lens holder by a fixing means using a screw structure. The O-ring is sandwiched between the first lens and the lens holder in the optical axis direction. The first lens and the lens holder are joined together with an adhesive, and the adhesive is a disassemblable adhesive that can be released after bonding by applying a specific treatment to the joint. The lens positioned closer to the image than the first lens is crimped and fixed to the lens holder. Lens unit.

2. The first lens is a plastic lens, The fixing means is composed of a male screw formed on the outer circumferential surface of the first lens and a female screw formed on the inner circumferential surface of the lens holder. The lens unit according to claim 1.

3. The first lens and the lens holder, apart from the fixing means, have an optical axis positioning portion that contacts each other in the optical axis direction and determines the optical axis position of the first lens relative to the lens holder. When we refer to the direction perpendicular to the optical axis as the radial direction, The first lens has a flange portion that is on the object side of the male screw and extends radially outward from the position of the male screw, The optical axis positioning portion is composed of the image surface of the flange portion and the surface of the lens holder opposite it. The lens unit according to claim 2.

4. When we refer to the direction perpendicular to the optical axis as the radial direction, The first lens and the lens holder, apart from the fixing means, have radial positioning parts that contact each other radially and determine the radial position of the first lens relative to the lens holder. The first lens has a cylindrical or columnar fitting portion on the image side of the male screw, The radial positioning portion is composed of the outer circumferential surface of the fitting portion and the surface of the lens holder facing it. The lens unit according to claim 2.

5. When we refer to the direction perpendicular to the optical axis as the radial direction, The first lens and the lens holder, apart from the fixing means, have radial positioning parts that contact each other radially and determine the radial position of the first lens relative to the lens holder. The first lens has a cylindrical or columnar fitting portion on the object side of the male screw, The radial positioning portion is composed of the outer circumferential surface of the fitting portion and the surface of the lens holder facing it. The lens unit according to claim 2.

6. The outer circumferential surface of the fitting portion is positioned radially outward from the position of the O-ring. The lens unit according to claim 4 or 5.

7. The first lens is a plastic lens having a cylindrical portion. The fixing means is composed of a male thread formed on the outer circumferential surface of the lens holder and a female thread formed on the inner circumferential surface of the cylindrical portion. The lens unit according to claim 1.

8. The first lens and the lens holder, apart from the fixing means, have an optical axis positioning portion that contacts each other in the optical axis direction and determines the optical axis position of the first lens relative to the lens holder. An annular groove is formed on the image surface of the first lens. When we refer to the direction perpendicular to the optical axis as the radial direction, The female thread is formed on the radially outer wall surface of the groove portion, The optical axis direction positioning portion is composed of the bottom surface of the groove and the surface of the lens holder facing it. The lens unit according to claim 7.

9. The first lens and the lens holder, apart from the fixing means, have radial positioning parts that contact each other radially and determine the radial position of the first lens relative to the lens holder. The radial positioning portion is composed of the radially inner wall surface of the groove portion and the surface of the lens holder facing it. The lens unit according to claim 8.

10. The outer surface of the first lens is provided with recesses, protrusions, notches, knurling, serrations, splines, or other irregularities in areas not related to its optical performance that allow for circumferential engagement with jigs, tools, or fingers. The lens unit according to claim 2 or 7.

11. When we refer to the direction perpendicular to the optical axis as the radial direction, The first lens is, The lens section determines its optical performance, It has a non-lens portion that extends radially outward from the lens portion, Multiple holes are formed in the non-lens portion. The first lens is fixed to the lens holder by passing a screw through the hole in the non-lens portion. The lens unit according to claim 1.

12. The first lens and the lens holder, apart from the fixing means, have an optical axis positioning portion that contacts each other in the optical axis direction and determines the optical axis position of the first lens relative to the lens holder. The optical axis direction positioning portion is composed of the image surface of the non-lens portion and the surface of the lens holder opposite it. The lens unit according to claim 11.

13. The first lens and the lens holder, apart from the fixing means, have radial positioning parts that contact each other radially and determine the radial position of the first lens relative to the lens holder. The first lens has a cylindrical or columnar fitting portion that is positioned radially inward from the O-ring, The radial positioning portion is composed of the outer circumferential surface of the fitting portion and the surface of the lens holder facing it. The lens unit according to claim 11.

14. The first lens and the lens holder, apart from the fixing means, have an optical axis positioning portion that contacts each other in the optical axis direction and determines the optical axis position of the first lens relative to the lens holder. The lens unit according to claim 1.

15. When we refer to the direction perpendicular to the optical axis as the radial direction, The first lens and the lens holder, apart from the fixing means, have radial positioning parts that contact each other radially and determine the radial position of the first lens relative to the lens holder. The lens unit according to claim 1.

Images