Lens unit

Abstract

To prevent damage to the first lens of the lens unit, the impact applied to the first lens is mitigated. [Solution] The lens unit 1 includes a lens group 10 including a first lens L1 located closest to the object (La), and a lens holder 2 that holds the lens group 10. The lens holder 2 includes a first holding portion 4 that holds the first lens L1. The first holding portion 4 includes a lens receiving portion 41 that receives the first lens L1 from the image side (Lb). The lens receiving portion 41 supports the first lens L1 via a plastically deformable shock-absorbing portion 9. The lens receiving portion 41 includes a seating surface 46 facing the first lens L1. The shock-absorbing portion 9 is a rib 47 protruding from the seating surface 46, and the tip of the rib 47 plastically deforms to absorb the impact applied to the first lens L1.

Description

[Technical Field]

[0001] The present invention relates to a lens unit.

[0002] Patent Document 1 discloses a lens unit for use in an optical apparatus. The lens unit of Patent Document 1 includes a plurality of lenses arranged on an optical axis, and a lens barrel (lens holder) that holds the plurality of lenses. The plurality of lenses include a first lens closest to the object side. The first lens is placed on an abutting surface portion (seat surface) provided on the lens barrel and facing the object side. A crimped portion for fixing the first lens is formed at a tip end of a first cylindrical portion surrounding an outer circumference of the first lens. A gap between the first lens and the lens holder is sealed by an O-ring. [Prior Art Literature] [Patent Literature]

[0003] [Patent Document 1] Japanese Unexamined Patent Publication No. 2024-147050 [Summary of the Invention] [Problem to be Solved by the Invention]

[0004] When a lens unit such as that disclosed in Patent Document 1 is incorporated into an in-vehicle camera, foreign matter such as a flying stone may collide with the first lens from the front while the vehicle is traveling. In such a case, stress concentration may occur at the portion to which the impact is applied, causing the first lens to break.

[0005] In view of the above problems, an object of the present invention is to alleviate impact applied to the first lens, thereby suppressing breakage of the first lens in a lens unit. [Means for Solving the Problem]

[0006] To solve the above problems, one embodiment of the lens unit according to the present invention comprises a lens group including a first lens located closest to the object, and a lens holder that holds the lens group, wherein the lens holder includes a first holding portion that holds the first lens, the first holding portion includes a lens receiving portion that receives the first lens from the image side, and the lens receiving portion supports the first lens via an impact absorbing portion that undergoes plastic or elastic deformation. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is a cross-sectional view of the lens unit of Embodiment 1 and a partially enlarged view thereof. [Figure 2] Figure 2 is an exploded cross-sectional view of the lens unit shown in Figure 1. [Figure 3] Figure 3 shows a cross-sectional perspective view of the lens holder and an enlarged view of the ribs. [Figure 4] Figure 4 shows a plan view of the lens holder and an enlarged view of the ribs. [Figure 5] Figure 5 is a cross-sectional view showing the tip shape (staircase-shaped) of the ribs in the impact-absorbing section of Modified Example 1. [Figure 6] Figure 6 is a cross-sectional view showing the tip shape (inclined) of the rib in the impact-absorbing section of Modified Example 2. [Figure 7] Figure 7 is a cross-sectional perspective view showing the shape of the ribs (shape extending in the circumferential direction) in the impact-absorbing section of Modified Example 3. [Figure 8] Figure 8 is a cross-sectional perspective view showing the shape of the ribs (shape extending in the circumferential direction) in the impact-absorbing section of Modification 4. [Figure 9] Figure 9 is a partial cross-sectional view of the lens unit of Embodiment 2. [Figure 10] Figure 10 is a partial cross-sectional view of the lens unit of Embodiment 3. [Figure 11] Figure 11 is a cross-sectional view of the lens unit of Embodiment 4. [Modes for carrying out the invention]

[0008] An embodiment of a lens unit to which the present invention is applied will be described below with reference to the drawings.

[0009] (Overall structure) Figure 1 is a cross-sectional view of the lens unit 1 of Embodiment 1 and a partially enlarged view thereof. Figure 2 is an exploded cross-sectional view of the lens unit 1 of Figure 1. In Figures 1 and 2, L is the optical axis of the lens unit 1. The direction along the optical axis L is defined as the optical axis direction. La is one side in the direction of the optical axis direction and is the object side (subject side) of the lens unit 1. Lb is the other side in the direction of the optical axis direction and is the image side of the lens unit 1.

[0010] The lens unit 1 comprises a lens group 10 having multiple lenses arranged in a single row in the optical axis direction, and a lens holder 2 that holds the lens group 10. The lens group 10 comprises a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, and a fifth lens L5. A light-shielding plate L6 is positioned between the third lens L3 and the fourth lens L4. An aperture L7 is positioned between the third lens L3 and the fourth lens L4.

[0011] Of the multiple lenses, the first lens L1, located furthest towards the object (La), is a glass lens. The second lens L2, the third lens L3, and the fifth lens L5 are plastic lenses. The fifth lens L5 and the fourth lens L4, located furthest towards the image (Lb), form a cemented lens. Note that the material, number, and configuration of the lenses held in the lens holder 2 are not limited to those described above. For example, the first lens L1 may be a plastic lens.

[0012] The lens holder 2 is made of resin. The lens holder 2 comprises a first holding part 4 that holds the first lens L1, a second holding part 5 positioned on the image side Lb of the first holding part 4, and a lens case 6 that surrounds the outer circumference of the second holding part 5. The lens case 6 extends from the outer circumference end of the first holding part 4 to the image side Lb. The second holding part 5 holds the second lens L2, the third lens L3, the fourth lens L4, and the fifth lens L5. A filter 7 positioned on the image side of the fifth lens L5 is held at the bottom of the second holding part 5.

[0013] As shown in Fig. 1 and Fig. 2, the first lens L1 is disposed on the lens holder 2 with the inner circumferential surface of the first holding portion 4 as a reference. Further, the second lens L2, the third lens L3, the fourth lens L4, and the fifth lens L5 are disposed with the inner circumferential surface of the second holding portion 5 as a reference.

[0014] The first holding portion 4 includes an annular lens receiving portion 41 that receives the outer peripheral portion of the first lens L1 from the image side, an annular stepped portion 42 recessed toward the image side Lb provided on the inner circumferential side of the lens receiving portion 41, and a peripheral wall portion 43 rising from the outer peripheral edge of the lens receiving portion 41 toward the object side La. The first lens L1 is caulked and fixed by a caulked portion 44 provided at the tip of the peripheral wall portion 43. An O-ring 8 for sealing the gap between the first lens L1 and the first holding portion 4 is disposed in the stepped portion 42.

[0015] The first lens L1 includes an object-side lens surface 11 convex toward the object side La, an image-side lens surface 12 concave toward the object side La, and an image-side flange surface 13 surrounding the outer peripheral side of the image-side lens surface 12. The image-side flange surface 13 is an annular flat surface perpendicular to the optical axis L. The O-ring 8 is compressed between the stepped portion 42 and the image-side flange surface 13.

[0016] The second holding portion 5 includes a cylindrical portion 51 provided on the inner circumferential side of the stepped portion 42 of the first holding portion 4, and a bottom portion 52 provided at an end portion on the image side Lb of the cylindrical portion 51 extending in the optical axis direction. As shown in Fig. 2, the bottom portion 52 includes a lens seating surface 53 abutting against the fourth lens L4, a recessed portion 54 recessed toward the image side Lb on the inner circumferential side of the lens seating surface 53, and a circular opening 55 provided in the center of the recessed portion 54. The fifth lens L5 is housed inside the recessed portion 54, but does not contact the inner surface of the recessed portion 54, and is positioned in the optical axis direction via the fourth lens L4.

[0017] An outer peripheral portion of the third lens L3 located on the object side La of the fourth lens L4 abuts against the outer peripheral portion of the fourth lens L4 in the optical axis direction via the diaphragm L7. Further, an outer peripheral portion of the second lens L2 located on the object side La of the third lens L3 abuts against the outer peripheral portion of the third lens L3 in the optical axis direction via the light shielding plate L6. The second lens L2 is caulked and fixed by a caulking portion 56 provided at an end portion of the cylindrical portion 51 on the object side La. The caulking portion 56 is provided at a tip end of the cylindrical portion 51 rising from an inner peripheral edge of the step portion 42 where the O-ring 8 is arranged toward the object side La.

[0018] (Shock absorbing portion) Figure 3 is a cross-sectional perspective view of the lens holder 2 and an enlarged view of the rib 47. Figure 4 is a plan view of the lens holder 2 and an enlarged view of the rib 47. As shown in Figure 3, the lens receiving portion 41 includes an annular seat surface 46 facing the image-side flange surface 13 of the first lens L1 from the image side Lb, and a convex portion protruding from the seat surface 46. As shown in Figure 2 and Figure 3, the convex portion protruding from the seat surface 46 is the rib 47. As shown in Figure 4, a plurality of ribs 47 linearly extending in the radial direction are equally arranged in the circumferential direction on the seat surface 46. The seat surface 46 is a plane perpendicular to the optical axis direction, and the plurality of ribs 47 have the same protruding height from the seat surface 46.

[0019] Tip ends of the plurality of ribs 47 face the image-side flange surface 13 of the first lens L1. When caulking and fixing the first lens L1, the tip end of each of the plurality of ribs 47 is slightly crushed. The shape of the rib 47 shown in Figure 3 is the shape before the tip end is crushed. The rib 47 has a shape that is more likely to undergo plastic deformation as it approaches the tip end side. As shown in the partially enlarged view of Figure 3, the rib 47 has a tapered cross-sectional shape when cut in the width direction, and the shape becomes narrower toward the tip end. A tip portion of the rib 47 before being crushed has a triangular cross-section, and the tip end is sharp.

[0020] When the first lens L1 is subjected to an impact from the object side La, such as a flying stone, the rib 47 that receives the first lens L1 absorbs the impact by plastically deforming. This suppresses damage to the first lens L1. Therefore, the multiple ribs 47 function as an impact absorption section 9. The lens receiving section 41 supports the first lens L1 via the impact absorption section 9. The first lens L1 is biased toward the object side La by the elastic restorative force of the O-ring 8 located on the inner circumference side of the lens receiving section 41. Therefore, after the tip of the rib 47 is crushed by the impact, the first lens L1 returns to its position before the impact by the elastic restorative force of the O-ring 8.

[0021] When the first lens L1 is subjected to a second impact, it collides again with the rib 47, whose tip has been deformed by the first impact, causing the tip of the rib 47 to deform further. Therefore, the second impact is also absorbed by the plastic deformation of the rib 47, and the impact applied to the first lens L1 is mitigated. The impact absorbing section 9 gradually increases the amount of deformation at the tip of the rib 47 with each impact. This allows it to absorb multiple impacts.

[0022] As shown in Figure 1, there is a predetermined gap between the second lens L2 and the first lens L1, and the two lenses are not in contact. The gap between the second lens L2 and the first lens L1 in the optical axis direction is set to a dimension that does not prevent the rib 47 from collapsing and functioning as the shock absorption part 9.

[0023] As shown in Figures 3 and 4, the radially inner end of the rib 47 does not extend to the inner periphery of the seating surface 46. The radially inner end of the rib 47 is a predetermined distance away from the inner periphery of the seating surface 46 on the outer side. The O-ring 8 is positioned on the inner side of the inner periphery of the seating surface 46. Therefore, by positioning the rib 47 away from the inner periphery of the seating surface 46, it is possible to avoid the crushed portion formed when the rib 47 is crushed by impact protruding towards the O-ring 8 and causing the O-ring 8 to become jammed.

[0024] (Main effects of Embodiment 1) As described above, the lens unit 1 of Embodiment 1 includes a lens group 10 including a first lens L1 located furthest towards the object La, and a lens holder 2 that holds the lens group 10. The lens holder 2 includes a first holding portion 4 that holds the first lens L1. The first holding portion 4 includes a lens receiving portion 41 that receives the first lens L1 from the image side Lb. The lens receiving portion 41 supports the first lens L1 via a plastically deformable shock absorbing portion 9.

[0025] Thus, with a structure that supports the first lens L1 via the shock-absorbing section 9, the impact on the first lens L1 is mitigated when an object such as a flying stone collides with the object-side lens surface 11 of the first lens L1. Therefore, there is less risk of the first lens L1 being damaged.

[0026] In Embodiment 1, the lens receiving portion 41 includes a seating surface 46 facing the first lens L1. The shock absorbing portion 9 is a rib 47 protruding from the seating surface 46, and the plastic deformation of the tip of the rib 47 absorbs the impact applied to the first lens L1. Thus, in Embodiment 1, the shock absorbing portion 9 is formed integrally with the seating surface 46. If a small shock absorbing member separate from the lens holder 2 and the first lens L1 is incorporated, the assembly workability of the lens unit 1 decreases. Furthermore, it is difficult to incorporate a small shock absorbing member with high precision. In contrast, in this embodiment, the decrease in assembly workability due to the provision of the shock absorbing portion 9 can be avoided, as can the decrease in the positional accuracy of the shock absorbing portion 9.

[0027] The shape of the impact-absorbing portion 9 protruding from the seat surface 46 may be any convex shape, and may be a shape other than the rib 47. For example, it may be a conical or pyramidal convex shape. The tip of the convex portion is preferably shaped to easily undergo plastic deformation due to impact. For example, it is preferable that it becomes thinner towards the tip.

[0028] The rib 47 of Embodiment 1 has a tapered cross-sectional shape when cut in the width direction. Because the tip of the rib 47 is tapered in this way, it easily undergoes plastic deformation. Therefore, an impact mitigation effect can be obtained.

[0029] In Embodiment 1, multiple radially extending ribs 47 are evenly arranged circumferentially on the seating surface 46 of the lens receiving portion 41. As a result, the impact is evenly distributed across the multiple ribs 47, allowing the first lens L1 to be supported in a balanced manner, and the multiple ribs 47 are evenly compressed. Therefore, compared to the case where the impact is concentrated on some of the ribs 47, causing some of the ribs 47 to compress more, the number of times the impact can be absorbed can be increased.

[0030] In Embodiment 1, an O-ring 8 is provided to seal the gap between the first lens L1 and the first retaining part 4, and the elastic restorative force of the O-ring 8 biases the first lens L1 toward the object side La. This allows the first lens L1 to return to its original position after the tip of the rib 47 is crushed by an impact. Therefore, the impact on optical properties is minimal.

[0031] In Embodiment 1, the O-ring 8 is positioned on a stepped portion 42 provided on the inner circumference side of the seating surface 46, and is compressed between the stepped portion 42, which is recessed toward the image side Lb relative to the seating surface 46, and the first lens L1. The radially inner end of the rib 47 is positioned away from the inner circumference of the seating surface 46 toward the outer circumference. This reduces the risk of the crushed portion formed by the crushing of the rib 47 protruding toward the O-ring and causing the O-ring to get caught.

[0032] The lens group 10 of Embodiment 1 includes a second lens L2 adjacent to the first lens L1 from the image side Lb. The lens holder 2 includes a second holding portion 5 that holds a plurality of lenses, including the second lens L2. The second lens L2 is held in a position where there is a gap between it and the first lens L1. It is held by part 5. In this way, if there is a gap between the second lens L2 and the first lens L1, the shock absorbing part 9 will not be unable to mitigate the impact due to the first lens L1 hitting the second lens L2.

[0033] (Variation 1) Figure 5 is a cross-sectional view showing the tip shape (stepped) of the rib 47A in the impact-absorbing section 9A of Modification 2. The impact-absorbing section 9A of Modification 1 is equipped with a stepped rib 47A whose height changes in stages. For example, the rib 47A shown in Figure 5 is equipped with a first portion 471 which has the highest protrusion height from the seat surface 46, a second portion 472 which has a lower protrusion height from the seat surface 46 than the first portion 471, and a third portion 473 which has an even lower protrusion height from the seat surface 46 than the second portion 472. The tip shape shown by the dashed line in Figure 5 is the tip shape of the first portion 471 before it is crushed when forming the crimped portion 44. The cross-sectional shapes of the first portion 471, the second portion 472, and the third portion 473 are all pointed at the tip. Although the tip of the rib 47A shown in Figure 5 is stepped with three steps, the number of steps may be two or four or more.

[0034] The stepped rib 47A at the tip collapses one step at a time with each collision. For example, in the first collision, the tip of the first part 471 collapses; in the next collision, the tip of the second part 472 collapses; and in the third collision, the tip of the third part 473 collapses. Therefore, the easily collapsible parts at the tip do not all collapse in the first collision, and each time multiple collisions occur, a portion of the easily collapsible parts at the tip collapses, mitigating the impact. This prevents a significant decrease in the impact mitigation effect during subsequent collisions.

[0035] (Modification 2) Figure 6 is a cross-sectional view showing the tip shape (inclined) of the rib 47B in the impact absorbing section 9B of Modified Example 2. The impact absorbing section 9B of Modified Example 2 is equipped with an inclined rib 47B whose height changes continuously. The tip shape shown by the dashed line in Figure 6 shows the shape before it is crushed when forming the crimped section 44. With an inclined tip rib 47B, the easily crushable part of the tip is not completely crushed in the first collision, but rather a part of the easily crushable part of the tip is crushed each time there is a collision. Therefore, similar to Modified Example 1, it is possible to avoid a significant decrease in the impact mitigation effect during the second and subsequent collisions.

[0036] (Variation 3) Figure 7 is a cross-sectional perspective view showing the shape (circumferentially extending shape) of the rib 47C in the impact absorbing section 9C of Modified Example 3. The impact absorbing section 9C of Modified Example 3 is equipped with a circumferentially extending rib 47C. The cross-sectional shape of the rib 47C is the same as that of the radially extending rib 47, and is tapered. In the example shown in Figure 7, an annular rib 47C is provided around the entire circumference of the seating surface 46. Similar to the radially extending rib 47, when an impact is applied to the first lens L1, the tip of the rib 47C that receives the first lens L1 collapses, mitigating the impact.

[0037] The circumferentially extending rib 47C may be provided in an annular shape around the entire circumference as shown in Figure 7, or it may be provided for a predetermined length in the circumferential direction. In this case, it is preferable to evenly distribute multiple ribs extending for a predetermined length in the circumferential direction. Furthermore, the rib 47C extending for a predetermined length in the circumferential direction may have its tip shaped like a step or inclined, similar to the radially extending ribs 47A and 47B.

[0038] (Modification 4) Figure 8 is a cross-sectional perspective view showing the shape (circumferentially extending shape) of the ribs 47D1 and 47D2 in the impact-absorbing section 9D of Modified Example 4. The impact-absorbing section 9D of Modified Example 4 is provided with annular ribs 47D1 and 47D2 that extend in the circumferential direction. The two ribs 47D1 and 47D2 are aligned radially. The two ribs 47D1 and 47D2 have different heights, with the outer rib 47D1 being the inner rib Rib 47D2 is higher than rib 47D1. With multiple ribs 47D1 and 47D2 of different heights, the tallest rib 47D1 will collapse in the first collision, and the next tallest rib 47D2 will collapse in the next collision. Therefore, the tips of all ribs will not collapse in the first collision. In this way, by providing multiple ribs of different heights, it is possible to avoid a significant decrease in impact mitigation effect during subsequent collisions.

[0039] Furthermore, in the case of radially extending ribs, a configuration with multiple ribs of different heights can be used, similar to Modification 4. In this case, it is preferable to have multiple ribs of the same height and to evenly distribute the multiple ribs of the same height in the circumferential direction. This ensures that the ribs that collapse simultaneously are evenly distributed in the circumferential direction, allowing for balanced support of the first lens L1.

[0040] (Embodiment 2) Figure 9 is a partial cross-sectional view of the lens unit 1E of Embodiment 2. The lens unit 1E of Embodiment 2 includes an impact absorbing section 9E, which is a separate impact absorbing member from the first lens L1 and the lens holder 2. As shown in Figure 9, the impact absorbing section 9E is sandwiched between the image-side flange surface 13 of the first lens L1 and the seating surface 46 of the lens holder 2. The impact absorbing section 9E undergoes elastic or plastic deformation. The lens receiving section 41 supports the first lens L1 via the elastically or plastically deformable impact absorbing section 9E. When an impact is applied to the first lens L1, the impact absorbing section 9E undergoes elastic or plastic deformation to mitigate the impact.

[0041] As the shock-absorbing part 9E, for example, an elastic material such as a rubber sheet can be used. Alternatively, the shock-absorbing part 9E may be an adhesive layer formed by the hardening of adhesive placed between the image-side flange surface 13 and the seat surface 46. Alternatively, the shock-absorbing part 9E may be a material that undergoes plastic deformation. For example, if it is a resin sheet with many easily crushable protrusions on its surface, or a resin sheet with voids partitioned by partition walls inside, the protrusions or partition walls will plastically deform upon impact, thereby mitigating the impact.

[0042] (Embodiment 3) Figure 10 is a partial cross-sectional view of the lens unit 1F of Embodiment 3. In the lens unit 1F of Embodiment 3, the shock-absorbing portion 9F is positioned on the first lens L1. The shock-absorbing portion 9F is a protrusion that extends from the image-side flange surface 13 of the first lens L1. The shape of the protrusion can be the same as that of the rib 47 of Embodiment 1 and its modified form. The shock-absorbing portion 9F shown in Figure 10 is a rib 47F that protrudes from the image-side flange surface 13 and extends radially. If the first lens L1 is a plastic lens, the plastically deformable rib 47F can be formed integrally with the first lens L1.

[0043] In Embodiment 3, the lens support portion 41 supports the first lens L1 via a plastically deformable shock-absorbing portion 9F. When an impact is applied to the first lens L1, the shock-absorbing portion 9F plastically deforms to mitigate the impact, similar to the embodiments described above.

[0044] (Embodiment 4) Figure 11 is a cross-sectional view of the lens unit 1G of Embodiment 4. As shown in Figure 11, the lens unit 1G comprises a lens group including a first lens L11 and a lens holder 2G that holds the lens group. The lens group is such that the first lens L11 is held in a first holding portion 4G of the lens holder 2G, and the other lenses are held in a second holding portion 5G. The first lens L11 has an annular step portion 14 that is recessed toward the object side La on the outer circumference side of the image side flange surface 13. An O-ring 8G is placed in the annular step portion 14 to seal the gap between the first holding portion 4G and the first lens L11. Embodiment 4 differs from the above embodiments in that the O-ring 8G seals the radial gap rather than the gap in the optical axis direction.

[0045] The first holding portion 4G includes a lens receiving portion 41 that receives the first lens L11 from the image side Lb, and a peripheral wall portion 43 that rises from the outer peripheral edge of the lens receiving portion 41 toward the object side La. The first lens L11 is fixed by a crimping portion 44 provided at the tip of the peripheral wall portion 43. The O-ring 8G seals the gap between the peripheral wall portion 43 and the annular step portion 14. The lens receiving portion 41 supports the first lens L11 via the shock absorbing portion 9G. The shock absorbing portion 9G is a rib 47 that protrudes from the seating surface of the lens receiving portion 41, similar to Embodiment 1. The form of the shock absorbing portion 9G can be any of the forms shown in Embodiments 1 to 3 and their modified examples above.

[0046] When an object such as a flying stone collides with the object-side lens surface 11 of the first lens L11, the impact absorber 9G of the lens unit 1G undergoes plastic or elastic deformation, thereby mitigating the impact on the first lens L11. Therefore, there is little risk of the first lens L11 being damaged. Even if the tip of the rib 47 of the first lens L11 is crushed by the impact and shifted toward the image side Lb, the elastic restorative force of the O-ring 8G positioned between the first lens L11 and the peripheral wall portion 43 biases it toward the object side La. Therefore, similar to the above embodiments, after the tip of the rib 47 is crushed by the impact, the elastic restorative force of the O-ring 8G returns the first lens L11 to its position before the impact.

[0047] (summary) The present invention can take the following forms. (1) A lens group including the first lens closest to the object, It has a lens holder that holds the aforementioned lens group, The lens holder includes a first holding portion for holding the first lens, The first holding portion includes a lens receiving portion that receives the first lens from the image side, The lens unit is characterized in that the lens receiving portion supports the first lens via an impact absorbing portion that undergoes plastic or elastic deformation.

[0048] (2) The lens receiving portion includes a seating surface facing the first lens, The aforementioned shock-absorbing portion is a protrusion that extends from the seat surface, The lens unit according to (1) above, characterized in that the tip of the convex portion undergoes plastic deformation to absorb the impact applied to the first lens.

[0049] (3) The lens unit according to (2) above, characterized in that the convex portion is a rib extending in the radial or circumferential direction.

[0050] (4) The lens unit according to (3) above, characterized in that the rib has a tapered cross-sectional shape when cut in the width direction.

[0051] (5) The lens unit according to (3) or (4) above, characterized in that the tip of the rib is stepped in height.

[0052] (6) The lens unit according to (3) or (4) above, characterized in that the tip of the rib is inclined in a way that the height changes continuously.

[0053] (7) The lens unit according to (3) or (4) above, characterized in that a plurality of ribs with different protrusion heights from the seat surface are arranged on the seat surface.

[0054] (8) The lens unit according to any one of (3) to (7) above, characterized in that a plurality of radially extending ribs are evenly arranged in the circumferential direction on the seat surface.

[0055] (9) It has an O-ring that seals the gap between the first lens and the first retaining part, The lens unit according to any one of (1) to (8) above, characterized in that the first lens is biased toward the object by the elastic restorative force of the O-ring.

[0056] (10) It has an O-ring that seals the gap between the first lens and the first retaining part, The elastic restorative force of the O-ring biases the first lens toward the object. The O-ring is positioned on a stepped portion provided on the inner circumference side of the seating surface and is compressed between the stepped portion, which is recessed toward the image side relative to the seating surface, and the first lens. The lens unit according to any one of (3) to (8) above, characterized in that the radially inner end of the rib is positioned away from the inner peripheral edge of the seating surface toward the outer peripheral side.

[0057] (11) The lens group includes a second lens adjacent to the first lens from the image side, The lens holder includes a second holding portion that holds a plurality of lenses, including the second lens. The lens unit according to any one of (1) to (10) above, characterized in that the second lens is held by the second retaining part at a position where there is a gap between it and the first lens.

[0058] (12) The lens unit according to (1) above, characterized in that the shock-absorbing portion is a shock-absorbing member sandwiched between the lens receiving portion and the first lens.

[0059] (13) The lens unit according to (12) above, characterized in that the impact-absorbing member is an elastic member.

[0060] (14) The first lens comprises an object-side lens surface, an image-side lens surface, and an image-side flange surface surrounding the image-side lens surface. The lens unit according to (1) above, characterized in that the shock-absorbing portion is a protrusion that protrudes from the image-side flange surface. [Explanation of Symbols]

[0061] 1, 1E, 1F, 1G...Lens unit, 2, 2G...Lens holder, 4, 4G...First retaining part, 5, 5G...Second retaining part, 6...Lens case, 7...Filter, 8, 8G...O-ring, 9, 9A, 9B, 9C, 9D, 9E, 9F, 9G...Shock absorbing part, 10...Lens group, 11...Object-side lens surface, 12...Image-side lens surface, 13...Image-side flange surface, 14...Annular step, 41...Lens receiving part, 42...Step, 43...Peripheral wall, 44...Crimped part, 46...Seat surface, 47, 47A, 47B, 47C, 47D1, 47D2, 47F...Rib, 51...Cylinder part, 52...Bottom part, 53...Lens seat surface, 54...Recess, 55...Opening, 56...Crimped part, 471...First part, 472... Part 2, 473... Part 3, L... Optical axis, L1, L11... First lens, L2... Second lens, L3... Third lens, L4... Fourth lens, L5... Fifth lens, L6... Shade plate, L7... Aperture, La... Object side, Lb... Image side

Claims

1. A lens group including the first lens closest to the object, It has a lens holder that holds the aforementioned lens group, The lens holder includes a first holding portion for holding the first lens, The first holding portion includes a lens receiving portion that receives the first lens from the image side, The lens unit is characterized in that the lens receiving portion supports the first lens via an impact absorbing portion that undergoes plastic or elastic deformation.

2. The lens receiving portion includes a seating surface facing the first lens, The aforementioned shock-absorbing portion is a protrusion that extends from the seat surface, The lens unit according to claim 1, characterized in that the tip of the convex portion undergoes plastic deformation to absorb the impact applied to the first lens.

3. The lens unit according to claim 2, characterized in that the convex portion is a rib extending in the radial or circumferential direction.

4. The lens unit according to claim 3, characterized in that the rib has a tapered cross-sectional shape when cut in the width direction.

5. The lens unit according to claim 3, characterized in that the tip of the rib is stepped in height.

6. The lens unit according to claim 3, characterized in that the tip of the rib is inclined in a way that the height changes continuously.

7. The lens unit according to claim 3, characterized in that a plurality of ribs with different protrusion heights from the seat surface are arranged on the seat surface.

8. The lens unit according to claim 3, characterized in that a plurality of radially extending ribs are evenly arranged in the circumferential direction on the seat surface.

9. It has an O-ring that seals the gap between the first lens and the first retaining part, The lens unit according to claim 1, characterized in that the first lens is biased toward the object by the elastic restorative force of the O-ring.

10. It has an O-ring that seals the gap between the first lens and the first retaining part, The first lens is biased toward the object by the elastic restorative force of the O-ring. The O-ring is positioned on a stepped portion provided on the inner circumference side of the seating surface and is compressed between the stepped portion, which is recessed toward the image side relative to the seating surface, and the first lens. The lens unit according to claim 3, characterized in that the radially inner end of the rib is positioned away from the inner peripheral edge of the seating surface toward the outer peripheral side.

11. The lens group includes a second lens adjacent to the first lens from the image side, The lens holder includes a second holding portion that holds a plurality of lenses, including the second lens. The lens unit according to claim 1, characterized in that the second lens is held by the second holding portion at a position where there is a gap between it and the first lens.

12. The shock-absorbing portion is a shock-absorbing member sandwiched between the lens receiving portion and the first lens. The lens unit according to claim 1, characterized in that it is the same as the one described in claim 1.

13. The lens unit according to claim 12, characterized in that the impact-absorbing member is an elastic member.

14. The first lens comprises an object-side lens surface, an image-side lens surface, and an image-side flange surface surrounding the image-side lens surface. The lens unit according to claim 1, characterized in that the shock-absorbing portion is a protrusion that extends from the image-side flange surface.

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