JP7759838B2 - Lens barrel and imaging device - Google Patents

Description

The present invention relates to a lens barrel and an imaging device.

Demand for high-resolution lenses is increasing in fields such as surveillance and medicine. Improving lens performance and increasing yield rates often requires adjusting the optical axes of the lens groups within the lens barrel. A known method for adjusting the optical axis is to correct misalignment between lens groups using a spring or other biasing member. Such conventional techniques include a technique that combines lens frame alignment and dustproofing (see, for example, Patent Document 1), a technique that adjusts the optical axis direction of the lens frame using a bayonet-like shape (see, for example, Patent Document 2), a mechanism that uses spring bias to align the lens frame (see, for example, Patent Document 3), and a mechanism that adjusts the position of the lens frame using spring bias and a bayonet-like shape (see, for example, Patent Document 4). Patent Document 1 also discloses a technique that seals the gap that occurs during alignment with a sealing member.

JP 2013-61513 A Japanese Patent Application Laid-Open No. 2008-145631 JP 2008-111932 A Japanese Patent Application Laid-Open No. 2019-28416

As lens barrels continue to become smaller and higher resolution, there is a demand for alignment mechanisms that can be used in small spaces. Furthermore, when an alignment mechanism is introduced, gaps naturally form in the lens barrel, so a sealed structure is needed to provide waterproofing and other measures.

However, the above-mentioned conventional technologies leave room for improvement in terms of achieving both a structure that enables alignment and a sealing structure that closes the gaps formed thereby. For example, Patent Document 1 does not disclose a structure for adjusting the Z-axis direction when aligning the lens frame, and while it discloses a sealing structure that is dustproof, it is difficult to say that it is sufficient from a waterproofing perspective. Furthermore, Patent Document 2 does not disclose a sealing structure that can accommodate alignment in the X-Y plane and waterproofing, and Patent Document 3 does not disclose a structure that enables alignment in the Z-axis direction or a sealing structure that can accommodate waterproofing. Patent Document 4 discloses an alignment structure that uses adjustment between the lens and sensor substrate, but does not disclose a structure that enables alignment between the lenses, nor does it disclose a sealing structure that can accommodate waterproofing.

One aspect of the present invention aims to realize a lens barrel that allows for alignment between lenses, is highly waterproof, and has a simple structure.

In order to solve the above problems, a lens barrel according to one aspect of the present invention comprises a fixed barrel section that holds a reference lens; an alignment frame that holds a lens to be aligned that is to be positioned on the optical axis of the reference lens and that engages with the fixed barrel section via a bayonet structure; a recess formed on one of the fixed barrel section and the alignment frame facing the other and capable of containing adhesive that is injected from outside the fixed barrel section with which the alignment frame is engaged; a first seal member that watertightly seals the gap between the peripheral edge of a front lens included in the reference lens or the lens to be aligned and the fixed barrel section or the alignment frame that holds the front lens; and a second seal member formed on the fixed barrel section that watertightly seals an opening that leads to the bayonet structure.

One aspect of the present invention makes it possible to realize a lens barrel that allows for alignment between lenses, has excellent waterproof properties, and has a simple configuration.

1 is a diagram schematically illustrating an imaging device according to a first embodiment of the present invention. FIG. 1 is an exploded perspective view of an imaging device according to a first embodiment of the present invention. 2 is a longitudinal cross-sectional view schematically showing a cross section of the imaging device of FIG. 1 taken along line AA. FIG. 2 is a diagram schematically illustrating a fixed barrel section as viewed from the image plane side in the first embodiment of the present invention. FIG. 2 is a diagram schematically illustrating an alignment frame as viewed from the image plane side in the first embodiment of the present invention. 5A and 5B are diagrams for explaining engagement of an alignment frame with a fixed barrel portion in the first embodiment of the present invention. FIG. 10 is an exploded perspective view of an imaging device according to a second embodiment of the present invention. FIG. 10 is a longitudinal sectional view of an imaging device according to a second embodiment of the present invention. FIG. 10 is a diagram schematically illustrating a fixed barrel portion as viewed from the image plane side in a second embodiment of the present invention. FIG. 10 is a diagram schematically illustrating a first alignment frame as viewed from the image plane side in a second embodiment of the present invention. FIG. 10 is a diagram schematically illustrating a second alignment frame as viewed from the image plane side in a second embodiment of the present invention. 10A and 10B are diagrams for explaining engagement of a first alignment frame and a second alignment frame with a fixed barrel portion in a second embodiment of the present invention. FIG. 10 is an exploded perspective view of an imaging device according to a third embodiment of the present invention. FIG. 10 is a longitudinal sectional view of an imaging device according to a third embodiment of the present invention. 10 is an enlarged cross-sectional view showing an engagement portion between a fixed barrel portion and an alignment frame according to a third embodiment of the present invention. FIG. 10A and 10B are diagrams illustrating tilt adjustment in a third embodiment of the present invention. FIG. 10 is an exploded perspective view of an imaging device according to a fourth embodiment of the present invention. FIG. 10 is a longitudinal sectional view of an imaging device according to a fourth embodiment of the present invention. FIG. 10 is a diagram schematically illustrating an alignment frame as viewed from the image plane side in a fourth embodiment of the present invention. FIG. 10 is a diagram schematically illustrating a fixed barrel portion as viewed from the image plane side in a fourth embodiment of the present invention. 10A and 10B are diagrams illustrating engagement of an alignment frame with a fixed barrel portion in a fourth embodiment of the present invention. FIG. 10 is an exploded perspective view of an imaging device according to a fifth embodiment of the present invention. FIG. 10 is a longitudinal sectional view of an imaging device according to a fifth embodiment of the present invention. FIG. 13 is a diagram schematically illustrating a fixed barrel portion as viewed from the image plane side in a fifth embodiment of the present invention. FIG. 13 is an enlarged cross-sectional view showing an engagement portion and a sealing portion between a fixed barrel portion and an alignment frame in a fifth embodiment of the present invention. FIG. 10 is an exploded perspective view of an imaging device according to a sixth embodiment of the present invention. FIG. 10 is a longitudinal sectional view of an imaging device according to a sixth embodiment of the present invention. FIG. 13 is a diagram schematically illustrating a fixed barrel portion as viewed from the image plane side in a sixth embodiment of the present invention. FIG. 13 is an enlarged cross-sectional view showing an engagement portion between a fixed barrel portion and an alignment frame in a sixth embodiment of the present invention. FIG. 13 is an enlarged cross-sectional view showing a sealing portion of a fixed barrel portion according to a sixth embodiment of the present invention.

[Embodiment 1]
Hereinafter, one embodiment of the present invention will be described in detail.

[composition]
FIG. 1 is a diagram schematically illustrating an imaging device according to this embodiment. FIG. 2 is an exploded perspective view of the imaging device according to this embodiment. FIG. 3 is a longitudinal cross-sectional view schematically illustrating a cross section of the imaging device of FIG. 1 taken along line A-A. As shown in FIG. 1, the imaging device 10 is composed of a box-shaped main body 11 and a cylindrical lens barrel 12. The main body 11 is composed of a housing 111, a board 112, and an imaging element 13. The imaging element 13 is a solid-state imaging element such as a CCD (Charge Coupled Device) sensor or a CMOS (Complementary Metal Oxide Semiconductor) sensor. In this manner, the imaging device 10 has the lens barrel 12 and the imaging element 13.

The housing 111 and the substrate 112 are made of metal, such as aluminum, or resin. The housing 111 is a box-shaped outer frame, and the substrate 112 is an outer frame shaped like one side of the box. The image sensor 13 is located in the center of the inner surface of the substrate 112. The substrate 112 is tightly adhered to the edge of the opening of the housing 111.

The lens barrel 12 includes a cylindrical outer frame tube 120 that stands on the other side of the housing section 111. The outer frame tube 120 is molded integrally with the housing section 111. A first threaded portion 130 is provided around the tip of the inner peripheral surface of the outer frame tube 120. The fixed lens barrel section 140, the alignment frame 150, and O-rings 160 and 170 are housed inside the outer frame tube 120.

Figure 4 is a schematic diagram showing the fixed lens barrel section in this embodiment as seen from the image plane side.

Fixed barrel section 140 is a roughly cylindrical member and is composed of a tube section 141 and a flange section 142. Fixed barrel section 140 is, for example, a one-piece molded product made of resin. Inside tube section 141, two lenses, a first lens 143 and a second lens 144, are held on the same optical axis. In this way, fixed barrel section 140 holds two lenses. The lenses held by fixed barrel section 140 are also referred to as "reference lenses." First lens 143 corresponds to the front lens in the optical system of the lens barrel.

The first lens 143 (front lens) is the lens located closest to the object in the lens barrel 12. If the fixed barrel section 140 has multiple lenses (multiple reference lenses), the lens located closest to the object is the first lens 143.

The flange portion 142 is a portion that extends outward from one end (object side) of the tubular portion 141. When viewed in a plan view, the flange portion 142 has three guide holes 1421 arranged at equal intervals in the circumferential direction. The guide holes 1421 have a generally L-shaped planar shape, with the short side of the L-shape extending radially from the flange portion 142 and the long side of the L-shape extending toward the inner periphery of the flange portion 142. In addition, an outer peripheral wall 145 is provided around the outer edge of the flange portion 142.

A second threaded portion 1451 is formed on the outer peripheral surface of the outer wall 145, which screws into the first threaded portion 130 of the outer frame tube 120 described above. The fixed barrel portion 140 is fixed to the outer frame tube 120 by screwing the first threaded portion 130 into the second threaded portion 1451, forming a single unit. In this way, the fixed barrel portion 140 is fixed to the inside of the outer frame tube 120 of the lens barrel 12.

A step 1422 of a specific thickness is formed between the long side of the guide hole 1421 on the object-side principal surface of the flange portion 142 and the outer peripheral wall 145. Furthermore, on the inner peripheral surface of the outer peripheral wall 145, at a position overlapping the step 1422 in the circumferential direction, an uneven portion 1452 formed of unevenness extending in the axial direction (parallel in the circumferential direction) is formed. Furthermore, annular first and second fitting grooves 146 and 147 are formed from the inside on the inner peripheral edge of this principal surface of the flange portion 142. Furthermore, a step 1423 of a specific thickness is formed between circumferentially adjacent guide holes 1421 on the image-plane-side principal surface of the flange portion 142.

Figure 5 is a diagram showing a schematic diagram of the alignment frame as seen from the image plane side in this embodiment. The alignment frame 150 is a roughly cylindrical body whose diameter on the image plane side is smaller than its diameter on the object side. The alignment frame 150 is, for example, a one-piece molded product made of resin. Inside the alignment frame 150, a third lens 151 and a fourth lens 152 are held on the same optical axis. The lenses held by the alignment frame 150 are also referred to as "lenses to be aligned."

The alignment frame 150 has three claws 153 that protrude further toward the object side along the axial direction from the larger-diameter edge on the object side. The claws 153 are arranged at equal intervals in the circumferential direction.

The claw portion 153 has an insertion shaft portion 1531 that is inserted into the short side portion of the guide hole 1421, and an engagement portion 1532 that extends outward from the tip of the insertion shaft portion 1531. Two grooves 1533 that extend circumferentially and are parallel to each other in the radial direction are formed on the tip surface (the end surface facing the object) of the engagement portion 1532. The outermost groove 1533 is a recess that is open to the outer periphery.

Figure 6 is a diagram illustrating the engagement of the alignment frame with the fixed barrel section in this embodiment. To engage the alignment frame 150 with the fixed barrel section 140, first, the claws 153 are inserted into the guide holes 1421 of the fixed barrel section 140 (left diagram in Figure 6). Next, the alignment frame 150 is engaged with the fixed barrel section 140 by rotating it along the long side of the guide holes 1421 relative to the fixed barrel section 140 (right diagram in Figure 6). The flange section 142 of the fixed barrel section 140, the guide holes 1421, and the claws 153 of the alignment frame 150 form a bayonet structure that engages the alignment frame 150 with the fixed barrel section 140, and the alignment frame 150 engages with the fixed barrel section 140 via the bayonet structure.

The base end surface of the engaging portion 1532 rides up and slides on the step portion 1422. The groove 1533, which is open toward the outer periphery of the engaging portion 1532, faces the uneven portion 1452 of the flange portion 142. The fixed barrel portion 140, which engages the alignment frame 150, is formed with a recess 180, which has the outermost groove 1533 and the uneven portion 1452 facing it as side walls and has an opening on the object side. In this way, the recess 180 is formed by the groove 1533 of the alignment frame 150 facing the uneven portion 1452 of the fixed barrel portion 140.

Furthermore, when the claw portion 153 is inserted into the guide hole 1421 of the fixed barrel portion 140 and the alignment frame 150 is rotated relative to the fixed barrel portion 140, the object side edge of the alignment frame 150 abuts against the step portion 1423 on the image plane side of the flange portion 142.

The position of the alignment frame 150 is adjusted relative to the fixed barrel portion 140 so that the optical axes of the third lens 151 and fourth lens 152 of the alignment frame 150 are aligned with the optical axes of the first lens 143 and second lens 144 of the fixed barrel portion 140. This adjustment of the optical axis will be explained in more detail later.

The O-ring 160 is fitted into the first fitting groove 146 of the fixed barrel portion 140. The first lens 143 is held in the fixed barrel portion 140 by abutting against the O-ring 160 from the object side.

The O-ring 170 is fitted into the second fitting groove 147 of the fixed barrel portion 140. Without the O-ring 170, a gap is formed between the fixed barrel portion 140 and the outer barrel 120 at the object-side end of the lens barrel. This gap has an opening 190 between the front lens and the outer barrel 120, which leads to the bayonet structure and into the fixed barrel portion, the alignment frame, or the image sensor. When the fixed barrel portion 140 approaches the edge of the outer barrel 120 due to screwing onto the outer barrel 120, the O-ring 170 is pressed against the inner surface of the outer barrel 120, and is in close contact with both the inner surface of the outer barrel 120 and the bottom surface of the second fitting groove 147. The O-ring 170 watertightly seals the opening 190 formed in the fixed barrel portion 140 that leads to the bayonet structure.

[assembly]
First, O-ring 160 is fitted into first fitting groove 146 of fixed barrel portion 140, and first lens 143 and second lens 144 are placed in fixed barrel portion 140. Furthermore, O-ring 170 is fitted into second fitting groove 147. First lens 143 and second lens 144 are positioned on the same specific optical axis by being held in fixed barrel portion 140. Third lens 151 and fourth lens 152 are also placed in alignment frame 150. Third lens 151 and fourth lens 152 are also positioned on the same specific optical axis by being held in alignment frame 150.

Next, the claw portions 153 of the alignment frame 150 are inserted into the guide holes 1421 of the fixed barrel portion 140, and the alignment frame 150 is rotated relative to the fixed barrel portion 140. As a result, the engagement portions 1532 of the claw portions 153 come into contact with the step portions 1422 on the object side of the flange portion 142 of the fixed barrel portion 140, and a recess 180 is formed by the groove 1533 on the outer periphery of the engagement portions 1532 and the outer periphery wall 145 of the flange portion 142. Furthermore, on the image plane side of the flange portion 142, the object side edge of the alignment frame 150 comes into contact with the step portions 1423. Once the alignment frame 150 is engaged with the fixed barrel 140, the position of the alignment frame 150 relative to the fixed barrel 140 is adjusted so that the optical axis of the lens in the fixed barrel 140 and the optical axis of the lens in the alignment frame 150 are the same (for example, substantially aligned with the optical axis OA of the image sensor).

Next, the fixed barrel portion 140, to which the alignment frame 150 is engaged and fixed, is inserted into the outer frame tube 120, and the second threaded portion 1451 of the fixed barrel portion 140 is screwed into the first threaded portion 130 of the outer frame tube 120 to fix the fixed barrel portion 140 inside the outer frame tube 120.

Next, the position of the image sensor 13 is adjusted so that the optical axis of the image sensor 13 on the substrate 112 is aligned with the optical axis of the lens in the lens barrel 12. Then, adhesive is applied to the edge of the opening of the main body 11, and the substrate 112 is attached. In this way, the image sensor 10 is obtained.

Here, we will explain lens centering, assuming that two axes that are perpendicular to the optical axis OA of the imaging device 10 and perpendicular to each other are the X-axis and Y-axis, respectively, and that the optical axis OA is the Z-axis.

[X and Y Direction Adjustment]
The fixed barrel 140, which is engaged with the alignment frame 150, is placed on the adhesive base. The adhesive base has three or more alignment pins that can be advanced and retracted radially using screws. The fixed barrel 140 is supported by the adhesive base so that the optical axis is positioned at the center in the radial direction. Then, the tips of the alignment pins are advanced to the alignment frame 150.

Next, a UV (ultraviolet) curing adhesive is injected into a recess 180 formed on the object side of the flange 142 of the fixed barrel 140, surrounded by the engagement portion 1532 of the alignment frame 150 and the uneven portion 1452 of the fixed barrel 140. Because the recess 180 opens onto the object side of the fixed barrel 140 engaged with the alignment frame 150, adhesive can be injected from the outside of the fixed barrel 140 and can be accommodated therein.

Next, the alignment pins are advanced and retracted as appropriate to center the optical axis in the alignment frame 150. The diameter of the claws 153 of the alignment frame 150 is slightly different from the diameter of the guide holes 1421 in the fixed barrel section 140. Therefore, by advancing and retracting the alignment pins, the position of the optical axis of the alignment frame 150 in the X-Y plane is adjusted within the range of this diameter difference. In this way, the position of the alignment frame 150 in the X-Y plane is adjusted so that the optical axis of the lens in the alignment frame 150 is aligned with the optical axis of the lens in the fixed barrel section 140.

Next, with the alignment frame 150 supported by the alignment pins in the optimal position relative to the fixed barrel 140, ultraviolet light is irradiated from a UV irradiator onto the adhesive injected and contained in the recess 180. This ultraviolet light irradiation hardens the adhesive in the recess 180, and the alignment frame 150 is fixed to the fixed barrel 140.

If you need to readjust the position of the alignment frame 150 in the XY plane relative to the fixed barrel section 140, peel off the adhesive that has hardened in the recess 180 and adjust the position of the alignment frame 150 using the same procedure as above.

[Z-direction adjustment]
In this embodiment, on the object side of the flange portion 142 of the fixed barrel portion 140, the engagement portion 1532 of the alignment frame 150 can abut against the step portion 1422. Furthermore, on the image plane side of the flange portion 142 of the fixed barrel portion 140, the object side edge of the alignment frame 150 can abut against the step portion 1423. Therefore, depending on the dimensional accuracy of the step portions 1422, 1423 in molding the fixed barrel portion 140, the distance (thrust distance) in the Z axis between the lens of the alignment frame 150 and the lens of the fixed barrel portion 140 can be adjusted to the desired distance (design value).

[Seal structure]
The substrate 112 is adhered to the edge of the opening of the main body 11 with an adhesive. Therefore, the imaging device 10 can exhibit sufficient waterproofing at the joint between the main body 11 and the substrate 112.

In addition, the housing 111 of the main body 11 and the outer frame 120 of the lens barrel 12 are molded as a single unit. This ensures sufficient waterproofing between the main body 11 and the lens barrel.

An O-ring 160 fitted into the first fitting groove 146 is located between the fixed barrel portion 140 and the front lens (first lens 143). The O-ring 160 is sandwiched between the object-side edge of the fixed barrel portion 140 and the periphery of the front lens, and is in close contact with both the fixed barrel portion 140 and the front lens around its entire circumference. In this way, the O-ring 160 watertightly seals the gap between the periphery of the front lens and the fixed barrel portion 140 that holds the front lens. Therefore, the imaging device 10 is sufficiently waterproof against the inside of the fixed barrel portion 140.

An O-ring 170 fitted into the second fitting groove 147 is located between the fixed barrel portion 140 and the open end of the outer barrel 120. The O-ring 170 is sandwiched between the inner surface of the outer barrel 120 and the fixed barrel portion 140, and is in close contact with both the outer barrel 120 and the fixed barrel portion 140 around the entire circumference near the open end of the outer barrel 120 in the gap between the outer barrel 120 and the fixed barrel portion 140 leading to the bayonet structure. In this way, the O-ring 170 watertightly seals the opening 190 formed in the fixed barrel portion 140 that leads to the bayonet structure. Therefore, the imaging device 10 is sufficiently waterproof against the outside of the fixed barrel portion 140 and the inside of the outer barrel 120.

[Summary of First Embodiment]
As is clear from the above description, the imaging device (10) has a lens barrel (12) and an imaging element (13). The lens barrel has a fixed barrel portion (14) that holds a reference lens (first lens 143 and second lens 144), an alignment frame (150) that holds lenses to be aligned (third lens 151 and fourth lens 152) to be positioned on the optical axis of the reference lens and that engages with the fixed barrel portion via a bayonet structure, a recess (180) formed in the alignment frame facing the fixed barrel portion and capable of containing adhesive that is injected from the outside of the fixed barrel portion with which the alignment frame engages, a first seal member (O-ring 160) that watertightly seals the gap between the peripheral edge of the front lens included in the reference lens and the fixed barrel portion that holds the front lens, and a second seal member (O-ring 170) that watertightly seals an opening (190) formed in the fixed barrel portion that leads to the bayonet structure.

In this way, the imaging device and lens barrel of this embodiment are simply constructed with a small number of parts. The alignment frame that holds the lens can be fixed at any position in the X and Y directions relative to the fixed barrel section that holds the lens. Furthermore, the object side of the protrusion in the bayonet structure on the alignment frame side serves as the contact surface, determining the thrust distance between the lens in the fixed barrel section and the lens in the alignment frame. Furthermore, when the fixed barrel section with the alignment frame engaged is inserted into the lens barrel, gaps that could serve as a route for water to enter are sealed by two O-rings. Therefore, the imaging device of this embodiment exhibits a sufficiently high level of waterproofing.

In the lens barrel, the reference lens includes the front lens. That is, the fixed barrel section has the front lens, and the fixed barrel section is fixed to the outer barrel frame, so no force is applied to the alignment frame when the O-ring is tightly attached to the outer barrel frame. This configuration is therefore even more effective in terms of achieving both waterproofness and alignment effects.

In addition, in the lens barrel, the fixed barrel section is fixed to the inside of the outer frame of the lens barrel. This configuration is even more effective in terms of preventing misalignment of the alignment frame relative to the fixed barrel section when fixing the fixed barrel section to the outer frame of the lens barrel.

Furthermore, in the lens barrel, the second sealing member is an O-ring that fits tightly between the outer frame and the fixed lens barrel in the direction along the optical axis in the gap that leads from between the outer frame and the front lens to the bayonet structure. This configuration is even more effective in terms of improving waterproofing with a simple structure.

Similarly, in a lens barrel, having an O-ring as the first sealing member is even more effective in terms of improving waterproofing with a simple configuration.

Furthermore, in the lens barrel, the recess into which adhesive can be injected from the outside has an uneven portion (1452) on the wall surface on its outer periphery. This increases the adhesive surface area. This configuration is therefore even more effective in terms of increasing the adhesive strength of the alignment frame to the fixed barrel portion.

Furthermore, in this imaging device, the main body and lens barrel are molded as a single unit, with no seams between them. This configuration is even more effective in terms of improving the waterproofness of the imaging device.

[Embodiment 2]
Other embodiments of the present invention will be described below. For ease of explanation, the same reference numerals will be used to designate components having the same functions as those described in the above embodiment, and the description thereof will not be repeated.

The imaging device of this embodiment has two alignment frames in the lens barrel, and the fixed barrel section is configured to engage with each alignment frame independently via a bayonet structure. Otherwise, the imaging device of this embodiment is configured substantially the same as the previously described first embodiment.

[composition]
Fig. 7 is an exploded perspective view of the imaging device according to this embodiment. Fig. 8 is a longitudinal cross-sectional view of the imaging device according to this embodiment. As shown in Fig. 7, the imaging device 20 has a housing 111, a substrate 112, an imaging element 13, an outer cylinder frame 120, and a lens barrel, and the lens barrel has a fixed barrel 240, a first alignment frame 250, a second alignment frame 260, and O-rings 160 and 170.

The fixed barrel section 240 holds the first lens 143 and the second lens 144 as reference lenses. The fixed barrel section 240 is configured to be able to independently engage with the first alignment frame 250 and the second alignment frame 260 via a bayonet structure. Figure 9 is a schematic diagram showing the fixed barrel section as seen from the image plane side in this embodiment. The fixed barrel section 240 has a tube section 141, a flange section 242, an outer peripheral wall 145, and an inner peripheral wall 244. The inner peripheral wall 244 is a convex rib that rises from the object-side principal surface of the flange section 242.

The flange portion 242 has three guide holes 2421 in addition to the three guide holes 1421. The three guide holes 2421 are arranged at equal intervals in the circumferential direction of the flange portion 242. The guide holes 1421 and the guide holes 2421 are arranged alternately in the circumferential direction of the flange portion 242. The guide holes 2421 have a generally L-shaped planar shape. The long side of the generally L-shaped portion extends along the outer peripheral wall 145 of the flange portion 242. The short side of the generally L-shaped portion extends in the radial direction of the flange portion 242.

Furthermore, in addition to having three each of steps 1422, 1423 and concave-convex portions 1452, the flange portion 2422 further has three sets of steps 2422, 2423 and concave-convex portions 2452. That is, steps 2422 of a specific thickness are formed between the long sides of the guide holes 2421 on the object-side principal surface of the flange portion 142 and the inner peripheral wall 244. Furthermore, concave-convex portions 2452 formed of concave-convex portions extending in the axial direction (parallel in the circumferential direction) are formed on the outer peripheral surface of the inner peripheral wall 244 at positions overlapping the steps 2422 in the circumferential direction. Furthermore, steps 2423 of a specific thickness are formed between circumferentially adjacent guide holes 2421 on the image-plane-side principal surface of the flange portion 242.

Figure 10 is a diagram showing a schematic view of the first alignment frame as seen from the image plane side in this embodiment. Figure 11 is a diagram showing a schematic view of the second alignment frame as seen from the image plane side in this embodiment.

The first alignment frame 250 is a roughly cylindrical member that holds the third lens 151 at its image-plane-side end. The first alignment frame 250 has essentially the same structure as the alignment frame 150 in the first embodiment described above, except that it further has three notches 254 arranged at equal intervals in the circumferential direction on its outer periphery. The notches 254 are arranged at equal intervals relative to the claws 153, and are shaped to allow the engagement portions 2632 of the claws 263 of the second alignment frame 260 (described later) to pass through in the axial direction.

The second alignment frame 260 is a roughly cylindrical member that holds the fourth lens 152 at its image-side end. When engaged with the fixed lens barrel 240, the second alignment frame 260 is configured to enclose the first alignment frame 250, which is also engaged with the fixed lens barrel 240.

The second alignment frame 260 has three claws 263 that correspond to the three sets of guide holes 2421, steps 2422 and 2423, and uneven portion 2452 that the fixed barrel section 240 has. The claws 263 protrude axially from the object-side edge of the second alignment frame 260 and have a configuration similar to that of the claws 153.

That is, the claw portion 263 has an insertion shaft portion 2631 that can be inserted into the long side portion of the guide hole 2421, and an engagement portion 2632 that can be inserted into the short side portion of the guide hole 2421. The engagement portion 2632 extends from the tip of the insertion shaft portion 2631 toward the center. The engagement portion 2632 has two grooves 2633 on its tip surface that extend circumferentially and are parallel to each other in the radial direction. The groove on the center side opens toward the center, forming a recess that is open toward the inner periphery.

[assembly]
The lens barrel and imaging device 20 in this embodiment are assembled in the same manner as the imaging device 10 described above, except that a second alignment frame 260 is further engaged with the fixed barrel portion 240. Figure 12 is a diagram for explaining the engagement of the first alignment frame and the second alignment frame with the fixed barrel portion in this embodiment.

When engaging the first alignment frame 250 with the fixed barrel 240, the claws 153 are first inserted into the guide holes 1421 of the fixed barrel 240 (see the left diagram in Figure 12). Next, the first alignment frame 250 is engaged with the fixed barrel 240 by rotating it along the long side of the guide holes 1421 relative to the fixed barrel 240 (see the right diagram in Figure 12). The flange 242 of the fixed barrel 240, the guide holes 1421, and the claws 153 of the first alignment frame 250 form a bayonet structure that engages the first alignment frame 250 with the fixed barrel 240. When the first alignment frame 250 is engaged with the fixed barrel 240, a recess 180 is formed with the outermost groove 1533 and the uneven portion 1452 facing it as side walls, and an opening on the object side.

To engage the second alignment frame 260 with the fixed barrel portion 240, first, the claws 253 of the second alignment frame 260 are passed through the notches 254 of the first alignment frame 250, which are engaged with the fixed barrel portion 240, and inserted into the guide holes 2421 of the fixed barrel portion 240 (see the left diagram in Figure 12). Next, the second alignment frame 260 is engaged with the fixed barrel portion 240 by rotating it along the long side of the guide holes 2421 relative to the fixed barrel portion 240 (see the right diagram in Figure 12). The flange portion 242 of the fixed barrel portion 240, the guide holes 2421, and the claws 253 of the second alignment frame 260 form a bayonet structure that engages the second alignment frame 260 with the fixed barrel portion 240. The fixed barrel section 240, to which the second alignment frame 260 is engaged, has a recess 280 with the innermost groove 2633 and the uneven section 2452 facing it as side walls, and an opening on the object side.

[X and Y Direction Adjustment]
The lens alignment of the lens barrel of this embodiment is performed in the same manner as in Embodiment 1. That is, the fixed barrel portion 240, to which the first alignment frame 250 and the second alignment frame 260 are engaged, is placed on an adhesive base. This adhesive base has two sets of three alignment pins that can be advanced and retracted radially by means of screws. The fixed barrel portion 240 is supported by the adhesive base so that the optical axis is centered radially, and the tips of the alignment pins of each set are advanced to the first alignment frame 250 and the second alignment frame 260, respectively.

Next, a UV-curable adhesive is injected into the recesses 180 and 280 that open to the object side of the flange 242 of the fixed barrel 240. Because the recesses 180 and 280 both open to the object side of the fixed barrel 240 with the first alignment frame 250 and second alignment frame 260 engaged, adhesive can be injected from the outside of the fixed barrel 240 and can be accommodated therein.

Then, each set of alignment pins is advanced or retracted as appropriate to center the optical axis in the first alignment frame 250 and the second alignment frame 260. The diameter of the claw portion 153 of the first alignment frame 250 is slightly different from the diameter of the guide hole 1421 of the fixed lens barrel portion 240, and the diameter of the claw portion 253 of the second alignment frame 260 is slightly different from the diameter of the guide hole 2421 of the fixed lens barrel portion 240. Therefore, by advancing or retracting the alignment pins, the positions in the X-Y plane of the optical axes in the first alignment frame 250 and the second alignment frame 260 are adjusted within the range of this diameter difference.

Next, ultraviolet light is irradiated from a UV irradiator onto the adhesive injected into and contained in the recesses 180 and 280. This ultraviolet light irradiation hardens the adhesive in the recesses 180 and 280, and the first alignment frame 250 and the second alignment frame 260 are each fixed to the fixed barrel portion 240.

[Z-direction adjustment]
The thrust spacing of the lenses in the lens barrel of this embodiment is the same as in Embodiment 1. That is, on the object side of the flange portion 242 of the fixed barrel portion 240, the engagement portion 1532 of the first alignment frame 250 can abut against the step portion 1422, and the engagement portion 2532 of the second alignment frame 260 can abut against the step portion 2422. Furthermore, on the image plane side of the flange portion 242 of the fixed barrel portion 240, the object side edge of the first alignment frame 250 can abut against the step portion 1423, and the object side edge of the second alignment frame 260 can abut against the step portion 2423. Therefore, depending on the dimensional accuracy of steps 1422, 1423 and steps 2422, 2423 in the molding of fixed barrel portion 240, the thrust distance between the lens of first alignment frame 250 and the lens of fixed barrel portion 240, and the thrust distance between the lens of second alignment frame 260 and the lens of fixed barrel portion 240 are adjusted to the desired (design value) distance.

[Seal structure]
The sealing structure of the imaging device and lens barrel in this embodiment is substantially the same as that in the above-described embodiment 1. Therefore, in this embodiment, the same waterproofness as in the above-described embodiment 1 is achieved.

[Summary of Second Embodiment]
The lens barrel (22) in this embodiment has two alignment frames, a first alignment frame (250) and a second alignment frame (260), each of which independently engages with the fixed barrel portion (240). Therefore, in this embodiment, in addition to the effects of the first embodiment described above, it is possible to align the lens in each of the multiple alignment frames with respect to the fixed barrel portion with high precision.

[Embodiment 3]
Other embodiments of the present invention will be described below. For ease of explanation, the same reference numerals will be used to designate components having the same functions as those described in the above embodiment, and the description thereof will not be repeated.

The imaging device of this embodiment is configured so that the tilt of the optical axis of the lens to be aligned, held by the alignment frame, in the lens barrel can be adjusted (tilt adjustment). Otherwise, the imaging device of this embodiment is configured substantially the same as the previously described first embodiment.

[composition]
Fig. 13 is an exploded perspective view of the imaging device according to this embodiment. Fig. 14 is a longitudinal cross-sectional view of the imaging device according to this embodiment. As shown in Fig. 13, imaging device 30 has substantially the same configuration as imaging device 10 in embodiment 1, except that imaging device 30 further includes spring 310 and washer 320 and includes fixed barrel 340 instead of fixed barrel 140.

The spring 310 abuts against the image-plane-side principal surface of the flange portion 142 of the fixed barrel portion 340, and also abuts against a step portion that widens from the inner wall surface of the barrel portion of the alignment frame 150 toward the center. The spring 310 biases the alignment frame 150 relative to the fixed barrel portion 340 in a direction that widens along the axial direction.

The fixed barrel portion 340 has a flange portion 342. Compared to the flange portion 142 of the fixed barrel portion 140, the flange portion 342 has a recess 3422 instead of a step portion 1422 on the object-side principal surface. Furthermore, the flange portion 342 does not have a step portion 1423 on the image-plane-side principal surface, and has an inner peripheral wall 344 that rises from the inner peripheral edge of the flange portion 342 toward the image plane side. One end of the spring 310 is fitted onto the inner peripheral wall 344 of the fixed barrel portion 340.

Figure 15 is an enlarged cross-sectional view showing the engagement portion between the fixed barrel and the alignment frame in this embodiment. The fixed barrel 340 has a recess 3422 at the position of the step 1422. The recess 3422 has approximately the same planar shape as the washer 320, and has a depth less than the thickness of the washer 320.

The washer 320 is, for example, a thin metal piece having a specific thickness. The washer 320 is housed in the recess 3422. Therefore, the washer 320 is interposed axially between the flange portion 342 of the fixed barrel portion 340 and the engagement portion 1532 of the alignment frame 150.

The biasing force of the spring 310 biases the engagement portion 1532 of the alignment frame 150 engaged with the fixed barrel portion 340 toward the washer 320 on the fixed barrel portion 340. In this way, the spring 310 serves as a biasing member that biases the alignment frame 150 engaged with the fixed barrel portion 340 in a direction that presses it against the fixed barrel portion 340 along the optical axis OA.

The washer 320 is housed in the recess 3422 and is interposed between the fixed barrel portion 340 and the alignment frame 150 in the axial direction. In this way, the washer 320 corresponds to a spacer arranged between the fixed barrel portion 340 and the alignment frame 150 in the bayonet structure in the direction along the optical axis OA.

[assembly]
A washer 320 having a specific thickness is housed in a recess 3422 of the fixed barrel portion 340, and with one end of the spring 310 fitted into the inner peripheral wall 344, the spring 310 is interposed between the fixed barrel portion 340 and the alignment frame 150, thereby engaging the alignment frame 150 with the fixed barrel portion 340. The method of engaging the alignment frame 150 with the fixed barrel portion 340 is carried out in the same manner as in the first embodiment described above.

[X and Y Direction Adjustment]
The position of the alignment frame 150 in the X and Y directions is adjusted in the same manner as in the first embodiment.

[Z-direction adjustment]
In this embodiment, the thrust distance between the lens of the fixed barrel 340 and the lens of the alignment frame 150 is adjusted by the thickness of the three washers 320 housed in the three recesses 3422 of the fixed barrel 340 .

In addition, in this embodiment, the tilt of the optical axis of the lens in the alignment frame 150 can be adjusted by setting the thickness of the three washers 320.

Figure 16 is a diagram illustrating tilt adjustment in this embodiment. When the three washers 320 have the same thickness, only the thrust distance between the lens in the fixed barrel 340 and the lens in the alignment frame 150 is adjusted according to the thickness of the washers 320. Here, the thicknesses of the three washers 320 are made different depending on their circumferential position on the fixed barrel 340. Because the bayonet structure of the alignment frame 150 (engagement portion 1532) is pressed against the fixed barrel 340 by the spring 310, the optical axis of the lens in the alignment frame 150 tilts within the range of adjustment angle θ according to the position and thickness of the washer 320. In this way, tilt adjustment of the optical axis of the lens in the alignment frame 150 is achieved in this embodiment.

[Seal structure]
The sealing structure of the imaging device and lens barrel in this embodiment is substantially the same as that in the above-described embodiment 1. Therefore, in this embodiment, the same waterproofness as in the above-described embodiment 1 is achieved.

[Summary of Embodiment 3]
This embodiment further includes a spring (310) that biases the alignment frame engaged with the fixed barrel in a direction that presses it against the fixed barrel along the optical axis, and a washer (320) that is disposed between the fixed barrel and the alignment frame in the bayonet structure in the direction along the optical axis, thereby enabling tilt adjustment of the lens in the alignment frame to be further achieved.

[Embodiment 4]
Other embodiments of the present invention will be described below. For ease of explanation, the same reference numerals will be used to designate components having the same functions as those described in the above embodiment, and the description thereof will not be repeated.

The imaging device of this embodiment is configured so that, in the lens barrel, the alignment frame holds a reference lens including a front lens, and the fixed lens barrel section holds the lens to be aligned. Otherwise, the imaging device of this embodiment is configured substantially the same as the previously described third embodiment.

[composition]
Fig. 17 is an exploded perspective view of the imaging device according to this embodiment. Fig. 18 is a longitudinal cross-sectional view of the imaging device according to this embodiment. As shown in Fig. 17, the lens barrel of imaging device 40 is made up of fixed barrel section 440, spring 310, alignment frame 450, washer 320, and O-rings 160 and 170.

Figure 19 is a schematic diagram showing the alignment frame as seen from the image plane side in this embodiment. The alignment frame 450 is a roughly cylindrical body with a smaller diameter on the image plane side than on the object side. The alignment frame 450 has an outer diameter smaller than the inner diameter of the fixed barrel portion 440, and can be accommodated inside through the object side opening of the fixed barrel portion 440. The alignment frame 450 holds the first lens 143 and second lens 144 on the same optical axis within it as lenses to be aligned. The first lens 143 is the front lens, and therefore in this embodiment, the lenses to be aligned include the front lens.

The alignment frame 450 has three claws 453 at its object-side end that protrude outward from its outer circumferential surface. The claws 453 are plate-like portions that protrude from the outer circumferential surface of the alignment frame 450 and have a substantially rectangular planar shape. The claws 453 have a recess 4532 on its object-side principal surface. The recess 4532 is capable of accommodating the washer 320, has substantially the same planar shape as the washer 320, and has a depth less than the thickness of the washer 320. The alignment frame 450 also has an inner peripheral wall 444 that rises toward the image plane, located more inward than the claws 453. A spring 310 is fitted onto the inner peripheral wall 444.

Figure 20 is a schematic diagram showing the fixed barrel section 440 as seen from the image plane side in this embodiment. The fixed barrel section 440 is a roughly cylindrical body with a smaller diameter on the image plane side than on the object side. The fixed barrel section 440 holds a third lens 151 and a fourth lens 152 on the same optical axis as reference lenses inside it. The fixed barrel section 440 also has a second threaded portion 1451 on the outer circumferential surface on the object side.

Furthermore, the fixed barrel section 440 has three cutouts 444 and three recesses 480 on the inner circumferential side of the object-side end face. The cutouts 444 and recesses 480 are all arranged at equal intervals in the circumferential direction and are arranged alternately. Each of the cutouts 444 is formed in a shape that allows the claws 453 of the alignment frame 450 to pass through. Each of the recesses 480 is formed in a shape that is open on the object-side and inner circumferential sides by a frame section that protrudes from the object-side end face of the fixed barrel section 440.

[assembly]
21 is a diagram illustrating the engagement of the alignment frame with the fixed barrel in this embodiment. In this embodiment, the spring 310 is inserted from the opening on the larger diameter side of the fixed barrel 440. In addition, a washer 320 of a specific thickness is placed in the recess 4532 of the claw 453 of the alignment frame 450.

Next, the claws 453 of the alignment frame 450 are aligned with the notches 444 of the fixed barrel 440, and the alignment frame 450 is pushed toward the inside of the fixed barrel 440 while the spring 310 is fitted into the inner peripheral wall 444 (left diagram in Figure 21). Then, in this state, the alignment frame 450 is rotated relative to the fixed barrel 440 to engage with it. The claws 453 of the alignment frame 450 are biased by the spring 310 toward the object-side end of the fixed barrel 440, but are restricted by this object-side end. In this way, the claws 453 of the alignment frame 450 and the object-side end of the fixed barrel form a bayonet structure. By engaging the alignment frame 450 with the fixed barrel 440, the recess 480 faces the outer peripheral surface of the alignment frame 450 in the radial direction. Therefore, the recess 480 is formed by the aforementioned frame portion and the outer peripheral surface of the alignment frame 450, and is a recess that opens toward the object side.

Next, adhesive is injected into the recess 480 that opens on the object side. Then, the position and tilt of the alignment frame 450 are adjusted. The position and tilt of the alignment frame 450 are adjusted in the same manner as in the third embodiment described above. The adhesive is then hardened, and the alignment frame 450 is fixed to the fixed barrel portion 440.

Next, the second threaded portion 1451 of the fixed barrel portion 440, inside which the alignment frame 450 is fixed, is threaded into the first threaded portion 130 of the outer frame tube 120, thereby fixing the fixed barrel portion 440 within the outer frame tube 120.

[Seal structure]
The sealing structure of the imaging device and lens barrel in this embodiment is substantially the same as that in the above-described embodiment 1. Therefore, in this embodiment, the same waterproofness as in the above-described embodiment 1 is achieved.

[Summary of the Fourth Embodiment]
In this embodiment, the front lens is held by the centering frame 450. As described above, this embodiment is suitable from the viewpoint of realizing centering of the lens disposed on the object side and tilt adjustment of the optical axis.

[Embodiment 5]
Other embodiments of the present invention will be described below. For ease of explanation, the same reference numerals will be used to designate components having the same functions as those described in the above embodiment, and the description thereof will not be repeated.

In the imaging device of this embodiment, the fixed lens barrel is integrally molded with the outer frame, which is composed of two members: the main body and the mount cover. Otherwise, the imaging device of this embodiment is essentially configured in the same way as the previously described third embodiment.

[composition]
Fig. 22 is an exploded perspective view of the imaging device according to this embodiment. Fig. 23 is a longitudinal cross-sectional view of the imaging device according to this embodiment. As shown in Fig. 22, the outer barrel frame of the imaging device 50 is made up of a fixed lens barrel portion 540 and a mount cover 550.

Figure 24 is a diagram showing a schematic view of the fixed barrel portion 540 in this embodiment as seen from the image plane side. The fixed barrel portion 540 is integrally molded with the portion of the outer frame 120 closer to the main body 11 than the first threaded portion 130 in embodiment 1. Otherwise, the fixed barrel portion 540 has substantially the same configuration as the fixed barrel portion 340 in the previously described embodiment.

The mount cover 550 has substantially the same configuration as the tip portion, including the first threaded portion 130, of the outer frame tube 120 in embodiment 1. The mount cover 550 is integrated with the fixed barrel portion 540 by threading the first threaded portion 130 into the second threaded portion 1451 of the fixed barrel portion 540. A gasket 560 is interposed between the mount cover 550 and the fixed barrel portion 540 to improve airtightness.

[assembly]
In this embodiment, engagement of the alignment frame 150 and lens alignment are performed before the housing part 111 is closed with the substrate part 112. Engagement of the alignment frame 150 and lens alignment are performed in the same manner as in the third embodiment described above.

Next, the housing 111 is closed with the substrate 112, and the mount cover 550 is fixed to the fixed barrel 540 via the gasket 560. By fixing the mount cover 550 to the fixed barrel 540, substantially the same configuration as in embodiment 3 is achieved.

Alternatively, the alignment frame 150 may be engaged with the fixed barrel 540, and then the housing 111 may be closed with the base plate 112, after which the position of the alignment frame 150 engaged with the fixed barrel 540 may be adjusted from the object side. In this case, it is possible to align the lens to be aligned with the alignment frame 150 with the image sensor 13 already attached.

[Seal structure]
25 is an enlarged cross-sectional view showing the engagement and sealing portions between the fixed barrel and the alignment frame in this embodiment. As shown in FIG. 25, the mount cover 550 is fixed to the fixed barrel 540 by threaded engagement. Therefore, the imaging device 50 has sufficient waterproofing at the joint between the mount cover 550 and the fixed barrel 540. In addition, the mount cover 550 is fixed to the fixed barrel 540 via a gasket 560. Therefore, the imaging device 50 has sufficient airtightness at the joint between the mount cover 550 and the fixed barrel 540.

[Summary of the Fifth Embodiment]
In this embodiment, the fixed barrel portion (540) is integrated with the outer frame of the lens barrel. Therefore, in this embodiment, it is possible to perform lens alignment in the alignment frame even when the image sensor is attached. Furthermore, in this embodiment, since the lens is aligned while fixed to the outer frame, it is even more effective in preventing misalignment of the lens when the fixed barrel portion is attached after alignment.

[Embodiment 6]
Other embodiments of the present invention will be described below. For ease of explanation, the same reference numerals will be used to designate components having the same functions as those described in the above embodiment, and the description thereof will not be repeated.

In the imaging device of this embodiment, the fixed lens barrel is integrally molded with the outer frame including the mount cover, and a sheet-like sealing member is used instead of an O-ring to watertightly seal the gap formed by the fixed lens barrel. Otherwise, the imaging device of this embodiment is essentially configured in the same way as the previously described embodiment 5.

[composition]
Fig. 26 is an exploded perspective view of the imaging device according to this embodiment. Fig. 27 is a longitudinal cross-sectional view of the imaging device according to this embodiment. As shown in Fig. 26, the imaging device 60 has a fixed barrel unit 640, an alignment frame 150, a substrate unit 112, an O-ring 160, a spring 310, a washer 320, and a sealing tape 670.

Figure 28 is a schematic diagram showing the fixed barrel section as seen from the image plane side in this embodiment. In the fixed barrel section 640, the flange section 342 is directly connected to the outer frame tube 120. The fixed barrel section 640 has a groove 620 extending circumferentially on the outer surface of the outer frame tube 120 between the flange section 342 and the tip of the outer frame tube 120. In other words, the wall surface of the groove 620 on the image plane side is the flange section 342. A step is formed on both opening edges of the groove 620 along the circumferential direction, recessed from the outer surface of the outer frame tube 120, and sealing tape 670 is affixed to this step.

[assembly]
29 is an enlarged cross-sectional view showing the engagement portion between the fixed barrel portion and the alignment frame in this embodiment. The engagement of the alignment frame 150 with the fixed barrel portion 640 is performed in the same manner as in the third embodiment described above. In this embodiment, the groove 1533 on the outside of the engagement portion 1532 opens toward the outer periphery. Therefore, when the alignment frame 150 engages with the fixed barrel portion 640, the groove 1533 and the object-side wall surface of the groove 620 form a recess 680 that opens toward the outer periphery. In this manner, in this embodiment, the recess 680 that opens into the interior of the groove 620 is formed by the engagement of the alignment frame 150 with the fixed barrel portion 640.

Adhesive is injected into the recess 680 from the outer periphery of the outer frame tube 120, and after adjusting the position and tilt of the alignment frame 150, the adhesive is cured and the alignment frame 150 is fixed to the fixed barrel section 640. In this embodiment, the position and tilt adjustment of the alignment frame 150 is performed in the same manner as in the third embodiment described above.

Next, sealing tape 670 is applied to the entire periphery of the recessed rib 620, sealing the opening. The recessed rib 620 is a space that extends to the bayonet structure formed by the fixed barrel portion 640, and the sealing tape 670 that covers and seals the opening of the recessed rib 620 along the circumferential direction of the outer frame tube 120 corresponds to the second sealing member in this embodiment.

[Seal structure]
30 is an enlarged cross-sectional view showing the sealed portion of the fixed barrel portion in this embodiment. The gap from the front lens to the inside of the fixed barrel portion 640 is sealed with an O-ring 160. Therefore, the imaging device 60 is sufficiently waterproof against the inside of the fixed barrel portion 640.

The recessed rib 620 faces the bayonet structure and serves as an opening for a gap that leads to the imaging element 13 via the bayonet structure. The recessed rib 620 is sealed all around with sealing tape 670, which adheres firmly and uses the step as a gap to seal the recessed rib 620 watertight. Therefore, the imaging device 60 is sufficiently waterproof against the imaging element 13.

[Summary of Sixth Embodiment]
In this embodiment, the fixed lens barrel portion (640) has a groove (620) extending circumferentially on the outer peripheral surface of the outer frame tube, and a recess (680) for accommodating adhesive opens into the groove. The opening of the groove is blocked by a member (sealing tape 670) that covers the outer frame tube circumferentially. This embodiment can achieve lens centering and waterproofing with fewer parts than the previous embodiments. Thus, this embodiment is even more effective in terms of achieving lens centering and waterproofing with a simpler configuration.

[Modification]
In the second embodiment, there may be three or more alignment frames. Such a configuration is preferable from the viewpoint of improving the accuracy of centering lenses including a heavy lens by centering the heavier lens alone.

〔summary〕
In the above-described embodiment, the lens barrel has a plurality of lens groups, and the centering of one of the lens groups is performed in a direction perpendicular to and parallel to the optical axis. The lens group to be centered is held by the centering frame.

In addition, biasing the alignment frame in a direction parallel to the optical axis using an elastic member such as a spring is suitable for adjusting the tilt of the lens group being aligned.

The alignment frame has claws extending radially, and the fixed barrel is configured to engage with these claws. Adhesive is then injected from the outside into recesses formed by both the alignment frame and the fixed barrel. This makes it possible to fix the alignment frame to the fixed barrel after position and tilt adjustments.

In this embodiment, the gap between the front lens and the fixed barrel or alignment frame is sealed with an O-ring, which is preferable from the perspective of waterproofing.

In the above-described embodiment of the present invention, a bayonet structure and biasing spring are used, which allows for space-saving and simplification with a small number of parts, and also provides an alignment mechanism that can achieve high water resistance and/or high airtightness.

As is clear from the above description, the lens barrel (10) in this embodiment of the present invention comprises a fixed barrel portion (140) that holds a reference lens; an alignment frame (150) that holds a lens to be aligned that is to be positioned on the optical axis of the reference lens and that engages with the fixed barrel portion via a bayonet structure; a recess (180) formed on one of the fixed barrel portion and the alignment frame facing the other and capable of containing adhesive injected from outside the fixed barrel portion with which the alignment frame is engaged; a first seal member (O-ring 160) that provides a watertight seal between the peripheral edge of the front lens included in the reference lens or the lens to be aligned and the fixed barrel portion or alignment frame that holds the front lens; and a second seal member (O-ring 170) formed on the fixed barrel portion that provides a watertight seal for an opening that leads to the bayonet structure. This configuration enables alignment between lenses, resulting in a lens barrel with excellent waterproofing and a simple configuration.

In an embodiment of the present invention, the lens barrel may further include a biasing member (spring 310) that biases the alignment frame engaged with the fixed barrel portion in a direction that presses it against the fixed barrel portion along the optical axis, and a spacer (washer 320) that is positioned between the fixed barrel portion and the alignment frame in the bayonet structure in the direction along the optical axis. This configuration is even more effective from the perspective of achieving tilt adjustment of the optical axis of the lens to be aligned with a simple configuration.

In an embodiment of the present invention, the reference lens may include a front lens. This configuration is even more effective in terms of more reliably maintaining the centering state when fixing the lens group to the outer barrel.

In an embodiment of the present invention, the lens to be aligned may include a front lens. This configuration is even more effective from the perspective of aligning the lens group on the object side.

In an embodiment of the present invention, the fixed barrel portion may be fixed to the inside of the outer frame portion of the lens barrel. This configuration is even more effective in terms of suppressing lens misalignment when fixing the aligned lens group to the imaging device.

In an embodiment of the present invention, the fixed barrel portion may be integral with the outer frame portion of the lens barrel. This configuration is even more effective in preventing lens misalignment when fixing an aligned lens group to an imaging device.

In an embodiment of the present invention, the second sealing member may be an O-ring that fits tightly against the outer frame and the alignment frame or fixed barrel in the direction along the optical axis in the gap that leads from between the outer frame and the front lens to the bayonet structure. This configuration is even more effective in terms of improving waterproofing with a simple configuration.

In an embodiment of the present invention, the fixed barrel portion may have a groove extending circumferentially on the outer peripheral surface of the outer frame portion, the recess opening into the groove, and the second sealing member may be a member that covers and closes the opening of the groove along the circumferential direction of the outer frame portion. This configuration is even more effective from the perspective of reducing the number of parts and simplifying the configuration.

In an embodiment of the present invention, the lens barrel may have two or more alignment frames, each of which may independently engage with the fixed barrel portion. This configuration is even more effective from the perspective of independently aligning multiple lens groups.

In an embodiment of the present invention, an imaging device includes the lens barrel and imaging element described above. Therefore, according to an embodiment of the present invention, it is possible to realize a high-performance, waterproof imaging device with a simple configuration.

This configuration enables imaging devices to be more compact, with improved performance and waterproofing. This will promote the use of imaging devices and reduce waste plastic by improving the utilization rate of production parts. This is expected to contribute to the development of industrial infrastructure and the achievement of the Sustainable Development Goals (SDGs) related to environmental conservation.

The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention.

10, 20, 30, 40, 50, 60 Imaging device 11 Main body 12 Lens barrel 13 Imaging element 111 Housing section 112 Base section 120 Outer frame barrel 140, 240, 340, 440, 540, 640 Fixed barrel section 141 Cylinder section 142, 242, 342 Flange section 143 First lens 144 Second lens 145 Outer peripheral wall 146 First fitting groove 147 Second fitting groove 150, 450 Alignment frame 151 Third lens 152 Fourth lens 153, 253, 263, 453 Claw section 160, 170 O-ring 180, 280, 480, 680, 3422, 4532 Recess 190 Opening 244, 344, 444 Inner peripheral wall 260 Second alignment frame 310 Spring 320 Washer 550 Mount cover 560 Gasket 670 Sealing tape 620 Concave ribs 1421, 2421 Guide holes 1422, 1423, 2422, 2423 Stepped portions 1452, 2452 Concave and concave portions 1531, 2631 Insertion shaft portions 1532, 2532, 2632 Engagement portions OA Optical axis θ Adjustment angle

Claims (10)

a fixed lens barrel portion that holds a reference lens;
an alignment frame that holds a lens to be aligned on the optical axis of the reference lens and engages with the fixed lens barrel via a bayonet structure;
a recess formed in one of the fixed barrel portion and the alignment frame facing the other, the recess being capable of accommodating adhesive injected from the outside of the fixed barrel portion engaged with the alignment frame;
a first seal member that watertightly seals a gap between a peripheral portion of a front lens included in the reference lens or the lens to be aligned and the fixed barrel portion or the alignment frame that holds the front lens;
a second seal member that watertightly seals an opening that is formed in the fixed barrel portion and leads to the bayonet structure;
A lens barrel having: a biasing member that biases the alignment frame engaged with the fixed barrel portion in a direction along the optical axis so as to press the alignment frame against the fixed barrel portion;
The lens barrel according to claim 1 , further comprising a spacer disposed between the fixed barrel portion and the alignment frame in the bayonet structure in the direction along the optical axis. The lens barrel of claim 1 or 2, wherein the reference lens includes the front lens. The lens barrel according to claim 1 or 2, wherein the lens to be aligned includes the front lens. The lens barrel described in any one of claims 1 to 4, wherein the fixed barrel portion is fixed to the inside of the outer frame portion of the lens barrel. The lens barrel described in any one of claims 1 to 4, wherein the fixed barrel portion is integral with the outer frame portion of the lens barrel. The lens barrel according to claim 5 or 6, wherein the second sealing member is an O-ring that tightly contacts the outer frame portion and the alignment frame or the fixed barrel portion in the direction along the optical axis in the gap that leads from between the outer frame portion and the front lens to the bayonet structure. the fixed barrel portion has a recessed line extending in a circumferential direction on an outer peripheral surface of the outer frame portion,
The recessed portion is open to the inside of the groove,
The second sealing member is a member that covers and closes the opening of the recessed strip along the circumferential direction of the outer frame portion.
The lens barrel according to claim 6. The lens barrel according to any one of claims 1 to 8, having two or more alignment frames, each of which independently engages with the fixed barrel portion. An imaging device comprising the lens barrel described in any one of claims 1 to 9 and an imaging element.