Lens unit, manufacturing method thereof, and camera module

Abstract

To provide a lens unit and a camera module, with which it is possible to prevent the deformation of plastic lenses adjacent to an intermediate ring in the axial direction and improve mass productivity, as well as easily assemble the intermediate ring.SOLUTION: Lenses 21, 22 adjacent to an intermediate ring 31 in the axial direction fit to the projection and depression of the intermediate ring 31, the outer circumferential surface of the intermediate ring 31 having an object-side circumferential surface 31c and an image-side circumferential surface 31d, the clearance between the object-side circumferential surface 31c and the inner circumferential surface of a lens barrel 10 being larger than the clearance between the image-side circumferential surface 31d and the inner circumferential surface of the lens barrel 10, the clearance between two lenses 21, 22 and the inner circumferential surface of the lens barrel 10 being larger than the clearance between the image-side circumferential surface 31d and the inner circumferential surface of the lens barrel 10. The intermediate ring 31 and the two lenses 21, 22 are integrated before being assembled into the lens barrel 10.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a lens unit, a method for manufacturing a lens unit, and a camera module. [Background technology]

[0002] In recent years, automobiles are equipped with cameras for capturing images of scenery outside the vehicle or the interior of the vehicle. Cameras mounted on automobiles (hereinafter referred to as vehicle-mounted cameras) are exposed to high or low temperature environments. Therefore, in order to compensate for temperature characteristics, vehicle-mounted cameras often use metal barrels and glass lenses. On the other hand, cameras mounted on terminals such as smartphones often use plastic lenses developed to realize high-performance, low-cost cameras.

[0003] One example of a conventional lens unit is disclosed in Patent Document 1. The lens unit disclosed in Patent Document 1 includes a metal lens barrel, a plurality of lenses arranged side by side along the axial direction of the lens barrel on the inner periphery side of the lens barrel, and an annular intermediate ring arranged between adjacent lenses in the axial direction. The intermediate ring is made of metal and has a convex portion formed toward the image side. The lens adjacent to the image side of the intermediate ring is made of resin and has a concave portion that fits into the convex portion of the intermediate ring. The gap between the outer circumferential surface of the resin lens and the inner circumferential surface of the lens barrel is set larger than the gap between the outer circumferential surface of the intermediate ring and the inner circumferential surface of the lens barrel.

[0004] According to such a lens unit, the concave portion of the plastic lens and the convex portion of the metal intermediate ring are formed to fit together, and the gap between the outer peripheral surface of the plastic lens and the inner peripheral surface of the metal barrel is larger than the gap between the outer peripheral surface of the metal intermediate ring and the inner peripheral surface of the metal barrel, so that even if the plastic lens expands at high temperatures due to its large difference in linear expansion coefficient with the barrel, the plastic lens will not be deformed by the force acting in the radially inward direction. In addition, the position of the optical axis of the plastic lens is determined by the metal intermediate ring, which has a small difference in linear expansion coefficient with the barrel and a small amount of deformation at high temperatures, so that optical axis deviation is suppressed. Therefore, the coaxiality of the multiple lenses arranged inside the barrel is ensured, and deterioration of optical characteristics can be suppressed. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2019-117265 Summary of the Invention [Problem to be solved by the invention]

[0006] Incidentally, in the conventional lens unit described above, it is possible to prevent high-temperature deformation of the lens adjacent to the image side of the intermediate ring, but it is not possible to prevent high-temperature deformation of the lens adjacent to the object side of the intermediate ring. Therefore, in order to suppress high-temperature deformation of the lens, product annealing is performed on the lens barrel in which all the lenses and intermediate rings are assembled (product) to stabilize the product in a deformed state. Product annealing usually takes about 48 hours, which is not suitable for mass production. In addition, the intermediate ring is press-fit into the telescope barrel, but at this time, the entire outer side surface of the intermediate ring (the entire side surface along the axial direction of the intermediate ring) interferes with the inner surface of the telescope barrel.Therefore, if the intermediate ring is tilted even slightly relative to the axis of the telescope barrel during installation, the intermediate ring will become pinched into the inner surface of the telescope barrel, making it difficult to install the intermediate ring.

[0007] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a lens unit, a manufacturing method for a lens unit, and a camera module that prevent deformation of a resin lens axially adjacent to an intermediate ring, thereby improving mass productivity, and that makes it easy to incorporate the intermediate ring. [Means for solving the problem]

[0008] In order to solve the above problems, a lens unit according to the present invention is a lens unit including a metal barrel, a plurality of lenses arranged side by side along an axial direction of the barrel on an inner peripheral side of the barrel, and an annular intermediate ring arranged between adjacent ones of the lenses in the axial direction, the intermediate ring is made of metal; The lens adjacent to the intermediate ring in the axial direction is engaged with the intermediate ring in a concave-convex manner, an outer peripheral surface of the intermediate ring has an object-side outer peripheral surface located on the object side in the axial direction, and an image-side outer peripheral surface located on the image side in the axial direction and adjacent to the object-side outer peripheral surface, a gap between the object-side outer peripheral surface and an inner peripheral surface of the lens barrel is larger than a gap between the image-side outer peripheral surface and an inner peripheral surface of the lens barrel, a gap between two of the lenses adjacent to each other in the axial direction of the intermediate ring and an inner peripheral surface of the lens barrel is larger than a gap between the image side outer peripheral surface of the intermediate ring and the inner peripheral surface of the lens barrel, The intermediate ring and the two lenses are bonded together with an adhesive.

[0009] According to this configuration, the two lenses adjacent to the intermediate ring in the axial direction are fitted to the intermediate ring in a concave-convex manner, and the gap between the two lenses and the inner peripheral surface of the lens barrel is larger than the gap between the image-side outer peripheral surface of the intermediate ring and the inner peripheral surface of the lens barrel, so that even if the plastic lens, which has a large difference in linear expansion coefficient from the lens barrel, expands at high temperatures, the plastic lens will not be deformed by the force acting in the radially inward direction. Therefore, since the plastic lens adjacent to the intermediate ring in the axial direction can be prevented from deforming, there is no need to perform product annealing, as in the past, and mass productivity can be improved. In addition, the gap between the object-side outer surface of the intermediate ring and the inner surface of the lens barrel is larger than the gap between the image-side outer surface of the intermediate ring and the inner surface of the lens barrel, and the intermediate ring and the two lenses are bonded with an adhesive.Furthermore, it is the image-side outer surface of the intermediate ring that contacts the inner surface of the lens barrel, so that the axes of the intermediate ring and the two lenses bonded with an adhesive can be prevented from tilting relative to the axis of the lens barrel and the intermediate ring becoming caught in the inner surface of the lens barrel, making it easier to assemble the intermediate ring.

[0010] Another lens unit according to the present invention is a lens unit including a metal barrel, a plurality of lenses arranged side by side along an axial direction of the barrel on an inner peripheral side of the barrel, and an annular intermediate ring arranged between adjacent ones of the lenses in the axial direction, the intermediate ring is made of metal; The lens adjacent to the intermediate ring in the axial direction is engaged with the intermediate ring in a concave-convex manner, an outer peripheral surface of the intermediate ring has an object-side outer peripheral surface located on the object side in the axial direction, and an image-side outer peripheral surface located on the image side in the axial direction and adjacent to the object-side outer peripheral surface, a gap between the object-side outer peripheral surface and an inner peripheral surface of the lens barrel is larger than a gap between the image-side outer peripheral surface and an inner peripheral surface of the lens barrel, a gap between two of the lenses adjacent to each other in the axial direction of the intermediate ring and an inner peripheral surface of the lens barrel is larger than a gap between the image side outer peripheral surface of the intermediate ring and the inner peripheral surface of the lens barrel, The intermediate ring and the two lenses are integrated together before being assembled into the lens barrel.

[0011] According to this configuration, the two lenses adjacent to the intermediate ring in the axial direction are fitted to the intermediate ring in a concave-convex manner, and the gap between the two lenses and the inner peripheral surface of the lens barrel is larger than the gap between the image-side outer peripheral surface of the intermediate ring and the inner peripheral surface of the lens barrel, so that even if the plastic lens, which has a large difference in linear expansion coefficient from the lens barrel, expands at high temperatures, the plastic lens will not be deformed by the force acting in the radially inward direction. Therefore, since the plastic lens adjacent to the intermediate ring in the axial direction can be prevented from deforming, there is no need to perform product annealing, as in the past, and mass productivity can be improved. In addition, the gap between the object-side outer surface of the intermediate ring and the inner surface of the lens barrel is larger than the gap between the image-side outer surface of the intermediate ring and the inner surface of the lens barrel, and the intermediate ring and the two lenses are integrated into an integrated body before being assembled into the lens barrel.Furthermore, since it is the image-side outer surface of the intermediate ring that contacts the inner surface of the lens barrel, the axis of the integrated body can be prevented from tilting relative to the axis of the lens barrel and causing the intermediate ring to bite into the inner surface of the lens barrel, thereby making it easier to assemble the intermediate ring.

[0012] In the above-described configuration of the present invention, the length in the axial direction of the object-side outer peripheral surface may be equal to the length in the axial direction of the image-side outer peripheral surface.

[0013] The longer the axial length of the object-side outer peripheral surface of the intermediate ring, the shorter the axial length of the image-side outer peripheral surface, so that the intermediate ring can be more effectively prevented from being pinched, while the axial length of the image-side outer peripheral surface that contacts the inner peripheral surface of the lens barrel becomes shorter, so that the radial positional stability of the intermediate ring decreases. Therefore, by making the axial length of the object-side outer peripheral surface equal to the axial length of the image-side outer peripheral surface, the intermediate ring can be prevented from being pinched while ensuring the radial positional stability of the intermediate ring.

[0014] In the above-mentioned configuration of the present invention, the convex portion and the concave portion, into which the intermediate ring and the lens adjacent to the object side of the intermediate ring are fitted together, have annular inclined surfaces that fit together, and the inclined surfaces are inclined so that their diameters become smaller toward the object side, The convex and concave portions of the intermediate ring that fit together with the adjacent lens on the image side of the intermediate ring may have annular inclined surfaces that fit together, and the inclined surfaces may be inclined so that their diameter becomes smaller as they approach the image side.

[0015] With this configuration, the convex and concave portions that fit together to allow the intermediate ring to engage with the adjacent lens on the image side have annular inclined surfaces that fit into each other, and the inclined surfaces are inclined so that their diameter becomes smaller toward the image side.Therefore, when assembling the intermediate ring to the lens adjacent to the image side, the inclined surfaces act as a guide, making the assembly work smoother. In addition, the convex and concave portions where the intermediate ring and adjacent lenses on the object side fit together have annular inclined surfaces that fit together, and the inclined surfaces are inclined so that their diameter becomes smaller toward the object side.Therefore, when assembling the lens adjacent to the object side to the intermediate ring, the inclined surfaces act as a guide, making the assembly work smoother. Therefore, the intermediate ring and the two lenses can be easily integrated together before being assembled into the lens barrel.

[0016] A method for manufacturing a lens unit according to the present invention is a method for manufacturing a lens unit including a metallic barrel, a plurality of lenses arranged side by side along an axial direction of the barrel on an inner peripheral side of the barrel, and an annular intermediate ring arranged between adjacent ones of the lenses in the axial direction, the intermediate ring being made of metal; an outer peripheral surface of the intermediate ring has an object-side outer peripheral surface located on the object side in the axial direction, and an image-side outer peripheral surface located on the image side in the axial direction and adjacent to the object-side outer peripheral surface, a gap between the object-side outer peripheral surface and an inner peripheral surface of the lens barrel is larger than a gap between the image-side outer peripheral surface and an inner peripheral surface of the lens barrel, a gap between two of the lenses adjacent to each other in the axial direction of the intermediate ring and an inner peripheral surface of the lens barrel is larger than a gap between the image side outer peripheral surface of the intermediate ring and the inner peripheral surface of the lens barrel, The two lenses adjacent to each other in the axial direction of the intermediate ring are integrated with each other by engaging the intermediate ring with each other in a concave-convex manner before being assembled into the lens barrel; The integrated body is then assembled into the lens barrel.

[0017] According to this configuration, the two lenses adjacent to the intermediate ring in the axial direction are fitted to the intermediate ring in a concave-convex manner, and the gap between the two lenses and the inner peripheral surface of the lens barrel is larger than the gap between the image-side outer peripheral surface of the intermediate ring and the inner peripheral surface of the lens barrel, so that even if the plastic lens, which has a large difference in linear expansion coefficient from the lens barrel, expands at high temperatures, the plastic lens will not be deformed by the force acting in the radially inward direction. Therefore, since the plastic lens adjacent to the intermediate ring in the axial direction can be prevented from deforming, there is no need to perform product annealing, as in the past, and mass productivity can be improved. In addition, the gap between the object-side outer surface of the intermediate ring and the inner surface of the lens barrel is larger than the gap between the image-side outer surface of the intermediate ring and the inner surface of the lens barrel, and the intermediate ring and the two lenses are integrated into an integrated body before being assembled into the lens barrel.Furthermore, since it is the image-side outer surface of the intermediate ring that contacts the inner surface of the lens barrel, the axis of the integrated body can be prevented from tilting relative to the axis of the lens barrel and causing the intermediate ring to bite into the inner surface of the lens barrel, thereby making it easier to assemble the intermediate ring.

[0018] A camera module according to the present invention includes the lens unit and an image sensor that captures an image formed by the lens unit.

[0019] According to the present invention, the camera module can achieve the same effects as the lens unit of the present invention described above. Effect of the Invention

[0020] According to the present invention, deformation of the resin lens axially adjacent to the intermediate ring is prevented, improving mass productivity, and the intermediate ring can be easily assembled. [Brief description of the drawings]

[0021] [Figure 1] FIG. 1 is a cross-sectional view showing a lens unit according to an embodiment of the present invention. [Diagram 2]FIG. 2 is an enlarged view of a main part in FIG. [Diagram 3] FIG. 3 is an enlarged view of the X-circle portion in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a cross-sectional view of a lens unit 100 according to the present embodiment. Fig. 2 is a cross-sectional view of a main part of the lens unit 100, and Fig. 3 is an enlarged view of an X edge part in Fig. 2. The lens unit 100 shown in FIG. 1 is used in, for example, an in-vehicle camera. This vehicle-mounted camera is, for example, built into a rearview mirror and captures images of the interior of the vehicle.

[0023] As shown in Fig. 1, lens unit 100 includes lens barrel 10, multiple lenses 21, 22, 23, 24, 25, intermediate rings (spacers) 31, 32, 33, optical filter 40, pressing member 70, and diaphragm members 81 and 82. Note that in Figs. 1 to 3, hatching (diagonal lines) indicating a cross section is applied only to lens barrel 10, and hatching is omitted for other parts.

[0024] The optical filter 40 is disposed at the end of the lens unit 100 on the image side where the lenses 21 to 25 form an image. Hereinafter, the axial direction of the cylindrical lens barrel 10 is referred to as the axial direction Z. The end of the lens unit 100 on the optical filter 40 side in the axial direction Z is referred to as the image side. The end of the lens unit 100 opposite to the image side in the axial direction Z is referred to as the object side. The lens unit 100 is disposed so that the object side faces the image target. As shown in FIG. 2, an image sensor 60 is disposed on the image side of the lens unit 100. The image sensor 60 is disposed in a camera case to which the lens unit 100 is attached in order to capture an image formed by the lens unit 100. As shown in FIG. 1, a pressing member 70 is attached to the end of the lens unit 100 on the object side in order to press the parts housed inside the lens barrel 10. The pressing member 70 is made of metal, for example, aluminum.

[0025] The lens barrel 10 is made of metal, for example, aluminum. The lenses 21-25, intermediate rings 31-33, and diaphragm members 81, 82 are inserted into the inner periphery of the lens barrel 10 and arranged side by side along the axial direction Z of the lens barrel 10 (hereinafter referred to as the axial direction Z). The lenses 21-25, intermediate rings 31-33, and diaphragm members 81, 82 are arranged in the following order from the image side to the object side: lens 21, intermediate ring 31, lens 22, lens 23, diaphragm member 81, intermediate ring 32, lens 24, diaphragm member 82, intermediate ring 33, and lens 25. The lenses 21-25 are arranged side by side along the optical axis (Z axis) with their optical axes aligned.

[0026] 2 and 3, the main parts of the lens unit 100 will be described below. The intermediate ring 31 is disposed between the lenses 21 and 22 that are adjacent to each other in the axial direction Z. The end of the lens barrel 10 on the image side is provided with a support portion 11 against which the lens 21 abuts. The support portion 11 is formed on the inside of the lens barrel 10 so as to protrude radially inward.

[0027] The lenses 22 and 23 are circular resin lenses. The outer diameter of the lenses 22 and 23 is smaller than the inner diameter of the lens barrel 10. Between the outer peripheral surfaces of the lenses 22 and 23 and the inner peripheral surface of the lens barrel 10, a gap of about 0.1 mm is provided around the entire circumference in the diameter direction at room temperature. Therefore, the radial positions of the lenses 22 and 23 are not determined by the inner peripheral surface of the lens barrel 10. The lens 23 is formed with a recess 23a that is recessed toward the image side in the axial direction Z. The lens 22 is also formed with a protrusion 22e that protrudes toward the image side in the axial direction Z, and the recess 23a and the protrusion 22e are engaged with each other. In addition, on the radially outer side of the recess 23a of the lens 23, an uneven portion 23d is formed extending radially outward from the recess 23a, and on the radially outer side of the convex portion 22e of the lens 22, an uneven portion 22d is formed extending radially outward from the convex portion 22e, and the uneven portion 23d and the uneven portion 22d are engaged with each other. In this way, lens 22 and lens 23 are fitted together in a concave-convex manner. In the above, convex portion 22e and concave-convex portion 22d are formed in lens 22, and concave portion 23a and concave-convex portion 23d are formed in lens 23. However, the concave portion and the concave-convex portion may be formed in lens 22, and the convex portion and the concave-convex portion may be formed in lens 23. Such lenses 22 and 23 are cemented lenses, and the lenses 22 and 23 are integrated together before being assembled into the lens barrel 10.

[0028] Furthermore, a step 12 in the axial direction Z is formed on the inner peripheral surface of the lens barrel 10 at a position facing the outer peripheral side surface (outer peripheral side surface) of the intermediate ring 31. A gap of approximately 0.1 mm is provided around the entire circumference in the diameter direction at room temperature between the upper half (half on the object side) of the outer peripheral side surface of the intermediate ring 31 and the inner peripheral surface of the lens barrel 10. A gap of approximately 0.01 mm is provided around the entire circumference in the diameter direction at room temperature between the lower half (half on the image side) of the outer peripheral side surface of the intermediate ring 31 and the inner peripheral surface of the lens barrel 10.

[0029] The intermediate ring 31 is an annular member and is made of metal, for example, aluminum. The lens 22 adjacent to the intermediate ring 31 on the object side in the axial direction is fitted with the intermediate ring 31 in a concave-convex manner. That is, the lens 22 is a circular resin lens, and includes a lens portion 22a that performs an optical function and a flange portion 22b formed on its outer periphery. The convex portion 31a and the concave portion 22c, where the lens 22 adjacent to the intermediate ring 31 on the object side and the intermediate ring 31 are fitted with each other in a concave-convex manner, have annular inclined surfaces K1 that fit together, and the inclined surfaces K1 are inclined so that the diameter becomes smaller toward the object side. The convex portion 31a is formed on the inner peripheral portion of the upper surface (object side surface) of the intermediate ring 31, protruding upward (to the object side), and the concave portion 22c is formed on the lower surface (image side surface) of the lens 22 between the lens portion 22a and the flange portion 22b, so as to be concave upward (to the object side), and in an annular shape over the entire circumference of the intermediate ring 31.

[0030] As described above, the outer diameter of lens 22 is smaller than the inner diameter of lens barrel 10, and a gap of about 0.1 mm is provided around the entire circumference in the diameter direction at room temperature between the outer peripheral surface of lens 22 and the inner peripheral surface of lens barrel 10. For this reason, the radial position of lens 22 is not determined by the inner peripheral surface of lens barrel 10. On the other hand, the gap between an image side outer surface 31d (described later) of the outer surface of the intermediate ring 31 and the inner surface of the lens barrel 10 is smaller than the gap between the outer surface of the lens 22 and the inner surface of the lens barrel 10. In other words, the gap between the outer surface of the lens 22 and the inner surface of the lens barrel 10 is larger than the gap between the image side outer surface 31d of the intermediate ring 31 and the inner surface of the lens barrel 10. Therefore, the radial position of the intermediate ring 31 is determined by the inner peripheral surface of the lens barrel 10. As described above, the lens 22 and the intermediate ring 31 are fitted together in a concave-convex manner. This means that the radial position of the lens 22 (the position of the optical axis of the lens 22) is determined by the radial position of the intermediate ring 31. Furthermore, since the lenses 22 and 23 are fitted together in a concave-convex manner as described above, the radial position of the lens 23 (the position of the optical axis of the lens 23) is determined by the radial position of the intermediate ring 31.

[0031] In this embodiment, an example is shown in which the recess 22c is formed on the inner periphery side of the lens 22, but the recess 22c may be formed on the outer periphery side of the lens 22. In addition, in this embodiment, an example is shown in which the protrusion 31a is formed on the inner periphery side of the intermediate ring 31, but the protrusion 31a may be formed on the outer periphery side of the intermediate ring 31. If the recess is formed on the intermediate ring 31 and the protrusion is formed on the lens 22, there is a problem in that the lens 22 receives a force from the intermediate ring 31 due to the difference in linear expansion coefficient between the intermediate ring 31 and the lens 22, resulting in deterioration of optical performance.

[0032] The intermediate ring 31 is formed so as to be fitted into the lens barrel 10. Specifically, the outer peripheral surface of the intermediate ring 31 has an object-side outer peripheral surface 31c located on the object side in the axial direction, and an image-side outer peripheral surface 31d located on the image side in the axial direction and adjacent to the object-side outer peripheral surface 31c. The object-side outer peripheral surface 31c and the image-side outer peripheral surface 31d have the same diameter and are flush with each other in the axial direction Z. As described above, a step 12 in the axial direction Z is formed on the inner peripheral surface of the lens barrel 10 at a position facing the outer peripheral side surface (outer peripheral side surface) of the intermediate ring 31. Then, object-side outer peripheral surface 31c is disposed opposite the inner peripheral surface above step 12 (object side) of the lens barrel 10 with a predetermined gap therebetween, and image-side outer peripheral surface 31d is disposed opposite the inner peripheral surface below step 12 (image side) with a small gap therebetween. In this way, the gap between the object side outer surface 31c and the inner peripheral surface of the lens barrel 10 is larger than the gap between the image side outer surface 31d and the inner peripheral surface of the lens barrel 10. For example, the gap between the object side outer surface 31c and the inner peripheral surface of the lens barrel 10 is about 0.1 mm, and the gap between the image side outer surface 31d and the inner peripheral surface of the lens barrel 10 is 0.01 mm.

[0033] The outer diameter of the image side outer peripheral surface 31d of the intermediate ring 31 is set in a range between a size slightly smaller than the inner diameter of the lens barrel 10 and a size slightly larger than the inner diameter of the lens barrel 10. The outer diameter of the image side outer peripheral surface 31d of the intermediate ring 31 is set in a range between a size 0.005 mm smaller than the inner diameter of the lens barrel 10 and a size 0.005 mm larger than the inner diameter of the lens barrel 10. In this way, when the outer diameter of the image side outer peripheral surface 31d of the intermediate ring 31 is set to 0 to +0.005 mm with respect to the inner diameter of the lens barrel 10, the intermediate ring 31 is inserted into the lens barrel 10 while the lens barrel 10 is at a high temperature. However, as described later, the intermediate ring 31, the lens 21, and the lenses 22 and 23, which are cemented lenses, are integrated before being assembled into the lens barrel 10. Furthermore, the length in the axial direction of the object-side outer peripheral surface 31c of the intermediate ring 31 is equal to the length in the axial direction of the image-side outer peripheral surface 31d.

[0034] In addition, the lens 21 adjacent to the intermediate ring 31 on the image side in the axial direction is fitted with the intermediate ring 31 in a concave-convex manner. That is, the lens 21 is a circular resin lens, and includes a lens portion 21a that performs an optical function and a flange portion 21b formed on its outer periphery. The convex portion 31b and the concave portion 21c, where the lens 21 adjacent to the intermediate ring 31 on the image side and the intermediate ring 31 are fitted with each other in a concave-convex manner, have annular inclined surfaces K2 that fit together, and the inclined surfaces K2 are inclined so that the diameter becomes smaller toward the image side. The convex portion 31b is formed on the inner peripheral portion of the lower surface (image side surface) of the intermediate ring 31, protruding downward (image side), and the concave portion 21c is formed on the upper surface (object side surface) of the lens 22 between the lens portion 21a and the flange portion 21b, so as to be concave downward (image side), and in an annular shape around the entire circumference of the intermediate ring 31.

[0035] As described above, the outer diameter of lens 21 is smaller than the inner diameter of lens barrel 10, and a gap of about 0.1 mm at room temperature is provided around the entire circumference in the diameter direction between the outer peripheral surface of lens 21 and the inner peripheral surface of lens barrel 10. For this reason, the radial position of lens 21 is not determined by the inner peripheral surface of lens barrel 10. On the other hand, the gap between the image side outer peripheral surface 31d of the intermediate ring 31 and the inner peripheral surface of the lens barrel 10 is smaller than the gap between the outer peripheral surface of the lens 21 and the inner peripheral surface of the lens barrel 10. In other words, the gap between the outer peripheral surface of the lens 21 and the inner peripheral surface of the lens barrel 10 is larger than the gap between the image side outer peripheral surface 31d of the intermediate ring 31 and the inner peripheral surface of the lens barrel 10. Therefore, the radial position of intermediate ring 31 is determined by the inner peripheral surface of lens barrel 10. As described above, lens 21 and intermediate ring 31 are fitted together in a concave-convex manner. This means that the radial position of lens 21 (the position of the optical axis of lens 22) is determined by the radial position of intermediate ring 31.

[0036] In this embodiment, an example is shown in which the recess 21c is formed on the inner periphery side of the lens 21, but the recess 21c may be formed on the outer periphery side of the lens 21. In addition, in this embodiment, an example is shown in which the protrusion 31b is formed on the inner periphery side of the intermediate ring 31, but the protrusion 31b may be formed on the outer periphery side of the intermediate ring 31. In addition, when the recess is formed on the intermediate ring 31 and the protrusion is formed on the lens 21, there is a problem in that the lens 21 receives a force from the intermediate ring 31 due to the difference in linear expansion coefficient between the intermediate ring 31 and the lens 21, resulting in deterioration of optical performance.

[0037] The lens 21 is arranged so that the image side surface of the flange portion 21b abuts against the support portion 11 of the lens barrel 10. The lens portion 21a of the lens 21 is curved from the flange portion 21b toward the image side. The object side surface of the lens portion 21a is a concave surface. The image side surface of the lens portion 21a is a concave surface at the center, and a convex surface at the periphery. The outer diameter of the lens 21 is smaller than the inner diameter of the lens barrel 10, and a gap of about 0.1 mm is provided between the outer peripheral surface of the lens 21 and the inner peripheral surface of the lens barrel 10 in the diameter direction over the entire circumference at room temperature. Therefore, the position of the lens 21 in the radial direction is not determined by the inner peripheral surface of the lens barrel 10.

[0038] In this embodiment, the recesses 21c and 22c have a recess amount of, for example, 0.2 mm. Moreover, the inclined surfaces K1 and K2 are inclined at, for example, about 20° with respect to the axial direction Z (optical axis direction) of the barrel 10. The outer peripheral surfaces of the recesses 21c and 22c are inclined surfaces that abut or are close to the inclined surfaces K1 and K2, and a gap of 0 to about 0.01 mm is formed between the inclined surfaces and the inclined surfaces K1 and K2.

[0039] The lens unit 100, together with the imaging element 60, a wiring board, a signal processing circuit, a flexible wiring sheet, a connector, etc., constitutes a camera module. Note that the camera module is one that includes at least the lens unit 100 and the imaging element 60. Note that the imaging element 60 may be a general imaging element such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor).

[0040] In addition, the intermediate ring 31, the lens 21, and the lenses 22 and 23, which are laminated lenses, are integrated before being assembled into the lens barrel 10. Since the lenses 22 and 23 are laminated lenses, the laminated lens (lenses 22 and 23) and the intermediate ring 31 are integrated by adhesively fixing the lens 22 and the intermediate ring 31 at the above-mentioned concave-convex fit portion with an adhesive or the like, and further, the intermediate ring 31 and the lens 21 are integrated by adhesively fixing the intermediate ring 31 and the lens 21 at the above-mentioned concave-convex fit portion with an adhesive or the like. As a result, the three lenses 21, 22, and 23 and the intermediate ring 31 are integrated to form an integrated object (sub-assembly). Then, a sub-assembly consisting of three lenses 21, 22, and 23 integrated with intermediate ring 31 is assembled into lens barrel 10. At this time, lens barrel 10 is heated to a prescribed temperature (for example, 70° C.) before assembling the sub-assembly, and after the temperature drops and stabilizes, aperture 81, intermediate ring 32, lens 24, aperture 82, intermediate ring 33, and lens 25 are assembled in that order into lens barrel 10. Finally, pressing member 70 is attached to the upper end (end on the object side) of lens barrel 10, and lenses 21-23, intermediate rings 31-33, and apertures 81 and 82 are sandwiched between pressing member 70 and support part 11 provided at the lower end of lens barrel 10.

[0041] According to this embodiment, the two lenses 21, 22 adjacent to the intermediate ring 31 in the axial direction are fitted to the intermediate ring 31 in a concave-convex manner, and the gap between the two lenses 21, 22 and the inner peripheral surface of the lens barrel 10 is larger than the gap between the image-side outer peripheral surface 31d of the intermediate ring 31 and the inner peripheral surface of the lens barrel 10. Therefore, even if the plastic lenses 21, 22, which have a large difference in linear expansion coefficient from the lens barrel 10, expand at high temperatures, the plastic lenses 21, 22 will not be deformed by a force acting in a radially inward direction. Therefore, deformation of the plastic lenses 21, 22 adjacent to the intermediate ring 31 in the axial direction can be prevented, and there is no need to perform product annealing, unlike the conventional method, and mass productivity can be improved.

[0042] In addition, the gap between the object side outer surface 31c of the intermediate ring 31 and the inner surface of the lens barrel 10 is larger than the gap between the image side outer surface 31d of the intermediate ring 31 and the inner surface of the lens barrel 10, and the intermediate ring 31 and the two lenses 21, 22, and lens 23 are integrated before being assembled into the lens barrel 10. Furthermore, since it is the image side outer surface 31d of the intermediate ring 31 that contacts the inner surface of the lens barrel 10, it is possible to prevent the axis of the sub-assembly from tilting relative to the axis of the lens barrel 10 and causing the intermediate ring 31 to bite into the inner surface of the lens barrel 10, thereby making it easier to assemble the intermediate ring 31.

[0043] In addition, since the axial length of the object-side outer peripheral surface 31c of the intermediate ring 31 is equal to the axial length of the image-side outer peripheral surface 31d, it is possible to ensure radial positional stability of the intermediate ring 31 while suppressing jamming of the intermediate ring 31.

[0044] Furthermore, the convex portion 31b and the concave portion 21c, which fit together with the adjacent lens 21 on the image side of the intermediate ring 31, have a mutually fitting annular inclined surface K2, and the inclined surface K2 is inclined so that its diameter becomes smaller toward the image side. Therefore, when the intermediate ring 31 is assembled to the adjacent lens 21 on the image side, the inclined surface K2 acts as a guide, making the assembly work smoother. In addition, the convex portion 31a and the concave portion 22c, which fit together with the adjacent lens 22 on the object side of the intermediate ring 31, have a mutually fitting annular inclined surface K1, and the inclined surface K1 is inclined so that its diameter becomes smaller toward the object side. Therefore, when the lens 22 adjacent to the object side is assembled to the intermediate ring 31, including the lens 23 integrated with the lens 22, the inclined surface K2 acts as a guide, making the assembly work smoother. Therefore, the intermediate ring 31 and the three lenses 21, 22, and 23 can be easily integrated together before being assembled into the lens barrel.

[0045] In this embodiment, the lenses 21, 22, and 23 are made of resin, but the other lenses 24 and 25 may be made of either resin or glass. [Explanation of symbols]

[0046] 10. Telescope tube 21, 22, 23, 24, 25 Lenses 31a, 31b Convex part 21c, 22c recess 31 Intermediate Ring 31c Object side outer surface 31d Image side outer peripheral surface 100 Lens unit K1,K2 Slope 60 Image sensor

Claims

1. A lens unit comprising: a metal barrel; a plurality of lenses arranged in line along an axial direction of the barrel on an inner peripheral side of the barrel; and an annular intermediate ring arranged between adjacent lenses in the axial direction, the intermediate ring is made of metal; The lens adjacent to the intermediate ring in the axial direction is engaged with the intermediate ring in a concave-convex manner, an outer peripheral surface of the intermediate ring has an object-side outer peripheral surface located on the object side in the axial direction, and an image-side outer peripheral surface located on the image side in the axial direction and adjacent to the object-side outer peripheral surface, a step is formed in the axial direction on an inner peripheral surface of the lens barrel at a position facing an outer peripheral surface of the intermediate ring; the object-side outer peripheral surface is disposed opposite, with a gap therebetween, to an inner peripheral surface of the lens barrel that is closer to the object side than the step; and the image-side outer peripheral surface is disposed opposite, with a gap therebetween, to an inner peripheral surface of the lens barrel that is closer to the image side than the step; a gap between the object-side outer peripheral surface and an inner peripheral surface of the lens barrel that is closer to the object side than the step is larger than a gap between the image-side outer peripheral surface and an inner peripheral surface of the lens barrel that is closer to the image side than the step, a gap between two of the lenses adjacent to each other in the axial direction of the intermediate ring and an inner peripheral surface of the lens barrel is larger than a gap between the image side outer peripheral surface of the intermediate ring and the inner peripheral surface of the lens barrel, A lens unit, characterized in that the intermediate ring and the two lenses are bonded together with an adhesive.

2. A lens unit comprising: a metal barrel; a plurality of lenses arranged in line along an axial direction of the barrel on an inner peripheral side of the barrel; and an annular intermediate ring arranged between adjacent lenses in the axial direction, the intermediate ring is made of metal; The lens adjacent to the intermediate ring in the axial direction is engaged with the intermediate ring in a concave-convex manner, an outer peripheral surface of the intermediate ring has an object-side outer peripheral surface located on the object side in the axial direction, and an image-side outer peripheral surface located on the image side in the axial direction and adjacent to the object-side outer peripheral surface, a step is formed in the axial direction on an inner peripheral surface of the lens barrel at a position facing an outer peripheral surface of the intermediate ring; the object-side outer peripheral surface is disposed opposite, with a gap therebetween, to an inner peripheral surface of the lens barrel that is closer to the object side than the step; and the image-side outer peripheral surface is disposed opposite, with a gap therebetween, to an inner peripheral surface of the lens barrel that is closer to the image side than the step; a gap between the object-side outer peripheral surface and an inner peripheral surface of the lens barrel that is closer to the object side than the step is larger than a gap between the image-side outer peripheral surface and an inner peripheral surface of the lens barrel that is closer to the image side than the step, a gap between two of the lenses adjacent to each other in the axial direction of the intermediate ring and an inner peripheral surface of the lens barrel is larger than a gap between the image side outer peripheral surface of the intermediate ring and the inner peripheral surface of the lens barrel, A lens unit, characterized in that the intermediate ring and the two lenses are integrated before being assembled into the lens barrel.

3. 3. The lens unit according to claim 1, wherein a length in the axial direction of the object-side outer peripheral surface is equal to a length in the axial direction of the image-side outer peripheral surface.

4. a convex portion and a concave portion, into which the intermediate ring and an adjacent lens on the object side of the intermediate ring are fitted together, have annular inclined surfaces that fit together, and the inclined surfaces are inclined so that their diameters become smaller toward the object side, The lens unit according to any one of claims 1 to 3, characterized in that a convex portion and a concave portion, into which an adjacent lens on the image side of the intermediate ring and the intermediate ring are fitted together, have annular inclined surfaces that fit together, and the inclined surfaces are inclined so that their diameters become smaller as they approach the image side.

5. A method for manufacturing a lens unit including a metal barrel, a plurality of lenses arranged along an axial direction of the barrel on an inner peripheral side of the barrel, and an annular intermediate ring arranged between adjacent lenses in the axial direction, the method comprising the steps of: the intermediate ring is made of metal; an outer peripheral surface of the intermediate ring has an object-side outer peripheral surface located on the object side in the axial direction, and an image-side outer peripheral surface located on the image side in the axial direction and adjacent to the object-side outer peripheral surface, a step is formed in the axial direction on an inner peripheral surface of the lens barrel at a position facing an outer peripheral surface of the intermediate ring; the object-side outer peripheral surface is disposed opposite, with a gap therebetween, to an inner peripheral surface of the lens barrel that is closer to the object side than the step; and the image-side outer peripheral surface is disposed opposite, with a gap therebetween, to an inner peripheral surface of the lens barrel that is closer to the image side than the step; a gap between the object-side outer peripheral surface and an inner peripheral surface of the lens barrel that is closer to the object side than the step is larger than a gap between the image-side outer peripheral surface and an inner peripheral surface of the lens barrel that is closer to the image side than the step, a gap between two of the lenses adjacent to each other in the axial direction of the intermediate ring and an inner peripheral surface of the lens barrel is larger than a gap between the image side outer peripheral surface of the intermediate ring and the inner peripheral surface of the lens barrel, The two lenses adjacent to each other in the axial direction of the intermediate ring are integrated with each other by engaging the intermediate ring with each other in a concave-convex manner before being assembled into the lens barrel; The manufacturing method of the lens unit is characterized in that the integrated body is assembled into the lens barrel.

6. 5. A camera module comprising: a lens unit according to claim 1; and an image sensor for capturing an image formed by the lens unit.

Images