JP2023056073A - lens unit - Google Patents

Abstract

To provide a lens unit that can suppress fogging of a first lens.SOLUTION: A lens unit 1 has: a lens barrel 20 that holds a first lens 11, a second lens 12, and a plurality of lenses; and an annular first elastic member 31 that is arranged between the first lens 11 and the second lens 12. The second lens 12 includes a second ring part 124 on its outer peripheral surface where a gate trace G1 remains. The lens barrel 20 includes a first cylinder part 21 that holds the first lens 11, and a second cylinder part 22 that is arranged inside the first cylinder part 21 and holds the second lens 12 and the plurality of lenses. The second cylinder part 22 includes a first portion 221 that holds the second lens 12. An inner peripheral surface of the first portion 221 is provided with a recess 223 on the inside of which the gate trace G1 is located. The first elastic member 31 is compressed between the first lens 11 and the second lens 12 to an extent that the first lens 11 and the second lens 12 are not brought into contact with each other.SELECTED DRAWING: Figure 2

Description

The present invention relates to a lens unit in which a plurality of lenses are held in a lens barrel.

2. Description of the Related Art A lens unit in which a plurality of lenses are accommodated in a lens holder is used in an imaging device mounted on an automobile, a surveillance camera, or the like. In this lens unit, the object-side lens surface of the first lens closest to the object is exposed to the outside from the lens barrel.

Such a lens unit is described, for example, in US Pat. In this document, a first lens and a plurality of lenses including a second lens arranged on the image side of the first lens are housed in a lens barrel made of resin. The lens barrel includes a first accommodating portion that accommodates a first lens and a second accommodating portion that accommodates a plurality of lenses including a second lens. An elastic member is arranged between the flange portion of the first lens and the flange portion of the second lens. Since the first lens is locked to the first accommodating portion by thermal caulking and the elastic member is compressed between the flange portion of the first lens and the flange portion of the second lens, airtightness inside the lens unit is maintained. kept constant.

Here, since the second lens is made of plastic, gate traces are formed on the outer peripheral surface of the flange portion of the second lens. In general, when the second lens is accommodated in the second housing portion, the gate marks are part of the outer peripheral surface of the flange portion so that the gate marks do not interfere with the inner peripheral surface of the second housing portion. It is provided on the flat part that cut the In this case, the outer diameter shape of the flange portion is D-shaped in plan view.

JP 2020-154123 A

As described above, when the flat portion is provided on the outer peripheral surface of the flange portion of the second lens, the radial width of the flange portion provided with the flat portion is small in plan view. For this reason, since the contact area with the elastic member is small at this portion, the elastic member cannot be properly brought into close contact with the flange portion of the second lens. As a result, if the lens unit is used for a long period of time, moisture that has passed through the elastic member may enter the inside of the lens unit.

In view of the above problems, an object of the present invention is to provide a lens unit capable of suppressing fogging of the first lens.

In order to solve the above problems, a lens unit according to the present invention includes a first lens arranged closest to the object side along an optical axis, and a second lens made of resin arranged on the image side of the first lens. a plurality of lenses arranged on the image side of the second lens; a lens barrel holding the first lens, the second lens and the plurality of lenses; the first lens and the second lens; and an annular first elastic member disposed between, wherein the first lens includes a first lens portion and a first annular portion surrounding the first lens portion, The second lens includes a second lens portion, and a second annular portion that surrounds the second lens portion and is a portion where gate traces remain on the outer peripheral surface, and the lens barrel includes the first lens. and a second cylindrical portion that holds the second lens and the plurality of lenses radially inside the first cylindrical portion, wherein the second cylindrical portion holds the second A cylindrical first portion for holding two lenses is provided on the inner peripheral surface of the first portion, and a gate trace accommodating recess in which the gate trace is located inside is provided with an open end facing the object side, The first elastic member is compressed between the first annular portion and the second annular portion to such an extent that the first lens and the second lens do not come into contact with each other.

In the present invention, the second lens has the second annular portion in which the gate trace remains on the outer peripheral surface, and the gate trace accommodating recess in which the gate trace is located inside is open on the inner peripheral surface of the first portion. It is provided with the end facing the object side. Therefore, since the gate marks are accommodated in the gate mark accommodating recess, it is not necessary to form the gate marks on the flat portion formed on the outer peripheral surface of the second annular portion. That is, there is no need to provide a flat portion on the outer peripheral surface of the second annular portion, and the outer diameter shape of the second annular portion remains circular. Therefore, compared to the case where the gate mark is formed on the flat portion of the outer peripheral surface of the lens, the contact area with which the first elastic member abuts can be ensured. can be properly adhered to. As a result, the airtightness between the first lens and the second lens can be secured, so fogging of the first lens can be suppressed.

In the present invention, the first elastic member is compressed between the first annular portion and the second annular portion to such an extent that the first lens and the second lens do not contact each other. Therefore, compared to the case where the first lens and the second lens are in contact with each other, it is easier to manage the amount of compression of the first elastic member. As a result, since it is easy to increase the airtightness inside the lens barrel, it is possible to suppress fogging of the image-side lens surface of the first lens. In addition, since the first lens and the second lens do not contact each other, when the first lens is held in the first cylindrical portion, the first elastic member is compressed, so that the second lens and the plurality of lenses are in contact with each other. It is difficult to apply a large force directly. Therefore, when the first lens is held by the first cylindrical portion, it is possible to prevent the lenses after the second lens from being damaged.

In the present invention, it is preferable that a plurality of recesses are provided in the inner peripheral surface of the first portion in the circumferential direction, and that some recesses among the plurality of recesses serve as the gate mark accommodating recesses. . With this configuration, when the second lens is held by the first portion, if the center of the second lens and the optical axis are misaligned, the second lens is held around the optical axis L with respect to the first portion. , the center of the second lens can be aligned with the optical axis.

In the present invention, it is preferable that the second lens has an annular stepped portion projecting toward the object side from the second annular portion and capable of radially positioning the first elastic member. In this way, it is easy to position the first elastic member in the radial direction. As a result, insufficient airtightness between the first lens and the second lens due to positional deviation of the first elastic member can be suppressed.

In the present invention, the third lens adjacent to the second lens among the plurality of lenses on the image side includes a third lens portion and a third annular portion surrounding the third lens portion. , the surface of the third annular portion facing the object side contacts the surface of the second annular portion facing the image side in the optical axis direction, and is closer to the object side than the bottom surface of the gate mark accommodating recess on the image side. is preferably located in In this way, the gate traces do not come into contact with the bottom surface of the gate trace accommodating recess, so that the third lens can reliably position the second lens.

In the present invention, it is possible to employ a mode in which a light shielding sheet is arranged between the second lens and the third lens.

In the present invention, it is preferable that first ribs for positioning the second lens in the radial direction are provided at a plurality of positions in the circumferential direction on the inner peripheral surface of the first portion. With this configuration, even when distortion is likely to occur due to the outer shape of the lens barrel, the first ribs can suppress the occurrence of misalignment of the second lens due to the distortion of the first portion. can.

In the present invention, the lens barrel includes a contact surface portion that contacts the first annular portion from the image side between the first cylindrical portion and the second cylindrical portion, and the contact surface portion is Preferably, an annular groove recessed toward the image side is provided, and an annular second elastic member compressed between the first annular portion and the groove is arranged in the groove. By doing so, it is easier to ensure the airtightness between the first lens and the second lens.

In the present invention, the second cylindrical portion includes a second portion that holds the plurality of lenses, and second ribs that radially position the plurality of lenses are provided on the inner peripheral surface of the second portion. It is preferable that they are provided at a plurality of locations in the direction. With this configuration, even when distortion is likely to occur due to the outer shape of the lens barrel, the second ribs can suppress the occurrence of misalignment of the number of lenses caused by the distortion of the second portion. can.

In the present invention, the lens barrel includes a positioning stepped portion that abuts from the image side on the image side lens that is arranged closest to the image side among the plurality of lenses, and the first elastic member has a , preferably overlaps with the positioning step. With this configuration, the force in the optical axis direction when the first elastic member is compressed by the first lens concentrates on the positioning stepped portion. As a result, distortion of the lens barrel can be suppressed during the operation of mounting the first lens.

In the present invention, the second lens has a second annular portion where gate traces remain on the outer peripheral surface, and a gate trace accommodating recess in which the gate traces are located inside is open on the inner peripheral surface of the first portion. It is provided with the end facing the object side. Therefore, compared to the case where the gate mark is formed on the flat portion formed on the outer peripheral surface of the lens, it is possible to secure the contact area with which the first elastic member abuts. As a result, airtightness between the first lens and the second lens can be ensured, so that fogging of the image-side lens surface of the first lens can be suppressed.

1 is a cross-sectional view of a lens unit to which the present invention is applied; FIG. It is an exploded perspective view of a lens unit. It is a sectional view of a lens barrel. It is the top view which looked at the lens barrel from the object side.

An embodiment of the present invention will be described with reference to the drawings. In the drawings referred to in the following description, the number and scale of each member are different in order to make each member recognizable on the drawing. In the following description, in the direction of the optical axis L in which the optical axis L extends, the object side is denoted by La and the image side by Lb.

(Structure of lens unit)
FIG. 1 is a sectional view of a lens unit to which the present invention is applied. FIG. 2 is an exploded perspective view of the lens unit. The lens unit 1 of this embodiment is used in an optical device such as an imaging device. The lens unit 1 has substantially the same configuration over the entire circumference of the optical axis L. As shown in FIG. The lens unit 1 shown in FIG. 1 has a wide-angle lens 10 in which a plurality of lenses are arranged in the optical axis L direction, and a lens barrel 20 that holds the wide-angle lens 10 inside. An imaging device is provided on the image side Lb of the lens barrel 20 . The imaging element is CMOS or the like.

(wide-angle lens)
As shown in FIGS. 1 and 2, the wide-angle lens 10 has, for example, a lens configuration of 6 lenses in 5 groups. In this embodiment, the wide-angle lens 10 includes the first lens 11 arranged closest to the object side La
, a second lens 12 arranged on the image side Lb of the first lens 11 , and a plurality of lenses arranged on the image side Lb of the second lens 12 . More specifically, the wide-angle lens 10 includes, from the object side La to the image side Lb, a first lens 11 having negative power, a second lens 12 having negative power, and a second lens 12 having positive power. It has three lenses 13, a fourth lens 14 with positive power, and a cemented lens 18 (fifth lens 15 and sixth lens 16) with positive power. A plurality of lenses are composed of a third lens 13 to a cemented lens 18 .

The first lens 11 is a glass lens or a plastic lens. The first lens 11 is a meniscus lens. The first lens 11 has a convex curved surface in which a first lens surface 111 on the object side La protrudes toward the object side La, and a second lens surface 112 on the image side Lb is concave toward the object side La. It has a concave surface. The first lens 11 includes a first lens portion 113 and a first annular portion 114 surrounding the first lens portion 113 . The first lens surface 111 and the second lens surface 112 constitute a first lens portion 113 . A flange surface 115 facing the image side Lb of the first annular portion 114 is positioned radially outward of the second lens surface 112 .

The second lens 12 is a plastic lens. The second lens 12 has a convex curved surface in which a first lens surface 121 on the object side La protrudes toward the object side La, and a second lens surface 122 on the image side Lb is concave toward the object side La. It has a concave surface. The second lens 12 includes a second lens portion 123 and a second annular portion 124 that surrounds the second lens portion 123 and has a gate trace G1 on the outer peripheral surface. The first lens surface 121 and the second lens surface 122 constitute a second lens portion 123 . The outer shape of the second annular portion 124 is circular in the optical axis L direction. The gate mark G1 is formed when the second lens 12 is resin-molded. The gate mark G1 slightly protrudes radially outward from the outer peripheral surface of the second annular portion 124 .

A flange surface 125 facing the object side La of the second annular portion 124 is positioned radially outward of the first lens surface 121 . A flange surface 126 facing the image side Lb of the second annular portion 124 is positioned radially outward of the second lens surface 122 . Further, the second annular portion 124 includes an annular step portion 127 protruding toward the object side La. The annular stepped portion 127 radially positions the first elastic member 31 .

The third lens 13 is a plastic lens. The third lens 13 has a convex curved surface in which a first lens surface 131 on the object side La protrudes toward the object side La, and a second lens surface 132 on the image side Lb is concave toward the object side La. It has a concave surface. The third lens 13 includes a third lens portion 133 and a third annular portion 134 which surrounds the third lens portion 133 and is a portion where gate traces G2 remain on a planar portion 134a of the outer peripheral surface. The first lens surface 131 and the second lens surface 132 constitute a third lens portion 133 . The external shape of the third annular portion 134 is D-shaped in the optical axis L direction. The gate mark G2 is formed when the second lens 12 is resin-molded. The gate marks G2 slightly protrude radially outward from the planar portion 134a. At this time, the gate mark G2 is located inside the virtual circle formed by the external shape of the third annular portion 134 . A flange surface 135 facing the object side La of the third annular portion 134 is positioned radially outward of the first lens surface 131 . A flange surface 136 facing the image side Lb of the third annular portion 134 is positioned radially outward of the second lens surface 132 .

The fourth lens 14 is a glass lens. The cemented lens 18 is a cemented lens of a fifth lens 15, which is a plastic lens with negative power, and a sixth lens 16, which is a plastic lens with positive power. The external shape of the fifth lens 15 is D-shaped in the optical axis L direction. A flat portion 15a of the outer peripheral surface of the fifth lens 15 has a gate trace G3 projecting slightly outward in the radial direction. The gate mark G3 is positioned inside the virtual circle formed by the external shape of the fifth lens 15 . The external shape of the sixth lens 16 is D-shaped in the optical axis L direction. On the flat portion 16a of the outer peripheral surface of the sixth lens 16, there remains a gate trace G4 projecting slightly outward in the radial direction. The gate mark G4 is located inside the virtual circle formed by the external shape of the sixth lens 16. As shown in FIG.

The lens unit 1 has an annular light shielding sheet 2 between a second lens 12 and a third lens 13, and an annular diaphragm 3 between a fourth lens 14 and a fifth lens 15. there is

The first lens 11 has a larger outer diameter than the second lens 12 , the third lens 13 , the fourth lens 14 and the cemented lens 18 . The second lens 12 , the third lens 13 , and the cemented lens 18 have substantially the same outer diameter, and in the cemented lens 18 , the fifth lens 15 has a larger outer shape than the sixth lens 16 . The fourth lens 14 has a smaller outer diameter than the second lens 12 and the like.

(lens barrel)
FIG. 3 is a cross-sectional view of the lens barrel. FIG. 4 is a plan view of the lens barrel viewed from the object side. The lens barrel 20 is made of resin. As the material of the lens barrel 20, crystalline plastics (polyethylene, polyamide, polytetrafluoroethylene) excellent in weatherability, amorphous plastics (polycarbonate, etc.) with relatively low moisture absorption, and the like are used. The lens barrel 20 is cylindrical. As shown in FIGS. 1 to 4, the lens barrel 20 includes a first barrel portion 21 that holds a first lens, a second barrel portion 22 that holds a second lens 12 and a plurality of lenses, and a first barrel portion 22 that holds a plurality of lenses. and an outer diameter cylindrical portion 23 extending from the image side Lb of the portion 21 . An annular concave portion 29 for thinning is formed between the outer cylindrical portion 23 and the second cylindrical portion 22 .

In addition, the lens barrel 20 includes a contact surface portion 24 that connects the first cylindrical portion 21 and the second cylindrical portion 22, a positioning step portion 25 that protrudes radially inward from the inner peripheral surface of the second cylindrical portion 22, Prepare.

The first cylindrical portion 21 has a cylindrical shape and surrounds the outer peripheral surface of the first lens 11 . A crimped portion 211 for fixing the first lens 11 is provided at the end portion of the first cylindrical portion 21 on the object side La. The inner diameter dimension of the first cylindrical portion 21 is slightly larger than the outer diameter dimension of the first lens 11 .

The contact surface portion 24 is an annular surface portion facing the object side La. The contact surface portion 24 contacts the flange surface 115 of the first annular portion 114 from the image side Lb. The contact surface portion 24 includes an annular groove portion 241 recessed toward the image side Lb. A second elastic member 32 is arranged in the groove portion 241 .

The second cylindrical portion 22 has a cylindrical shape. The inner diameter of the second cylindrical portion 22 is slightly reduced toward the image side Lb. The second cylindrical portion 22 includes a first portion 221 that holds the second lens 12 and a second portion 222 that holds a plurality of lenses. The first portion 221 surrounds the outer peripheral surface of the lens of the second lens 12 . A concave portion 223 is provided on the inner peripheral surface of the first portion 221 with the open end facing the object side La. The recess 223 is also a gate trace accommodating recess that accommodates the gate trace G1. In this embodiment, four recesses 223 are provided at equal intervals in the circumferential direction.

A plurality of first ribs 224 are provided in the circumferential direction on the inner peripheral surface of the first portion 221 . The first rib 224 protrudes radially inward and extends in the optical axis L direction. The first rib 224 radially positions the second lens 12 when the second lens 12 is press-fitted into the first portion 221 . In this embodiment, four first ribs 224 are provided at equal intervals in the circumferential direction.

The second portion 222 surrounds the outer peripheral surfaces of the multiple lenses. A plurality of second ribs 225 are provided in the circumferential direction on the inner peripheral surface of the second portion 222 . The second rib 225 protrudes radially inward and extends in the optical axis L direction. The second ribs 225 radially position the lenses when the lenses are pressed into the second portion 222 . In this embodiment, 12 second ribs 225 are provided at equal intervals in the circumferential direction. Also, the second rib 225 is arranged at a position not overlapping the first rib 224 in the optical axis L direction.

The positioning stepped portion 25 abuts on the cemented lens 18 (image side lens) arranged closest to the image side from the image side Lb. The positioning stepped portion 25 includes an overhanging portion 251 that overhangs radially inward at the end on the image side Lb.

(Fixation of wide-angle lens)
Next, fixing of the wide-angle lens 10 will be described. First, the cemented lens 18 to the second lens 12 are press-fitted into the second cylindrical portion 22 . The cemented lens 18 is positioned in the optical axis L direction by abutting the flange portion 150 of the fifth lens 15 against the positioning stepped portion 25 from the object side La. The fourth lens 14 is held by the holder 4, and the holder 4 contacts the flange portion 150 of the fifth lens from the object side La. The third annular portion 134 of the third lens 13 contacts the holder 4 via the diaphragm 3 from the object side La. The second lens 12 is press-fitted into the first portion 221 so that the gate mark G1 is positioned inside the recess 223 . The second annular portion 124 of the second lens 12 is in contact with the third annular portion 134 of the third lens 13 via the light shielding sheet 2 from the object side La. At this time, the flange surface 135 of the third annular portion 134 abuts against the flange surface 126 of the second annular portion 124 via the light shielding sheet 2, and extends from the bottom surface 226 of the concave portion 223 on the image side Lb toward the object side La. To position.

Here, in this embodiment, four recesses 223 are provided at equal intervals in the circumferential direction. Therefore, when the second lens 12 is press-fitted into the first portion 221 , if the center of the second lens 12 is misaligned with the optical axis L, the second lens 12 is positioned with respect to the first portion 221 . The center of the second lens 12 can be aligned with the optical axis L by rotating it about the axis L by 90°. After aligning the center of the second lens 12 with the optical axis L, the second lens 12 is press-fitted into the first portion 221 so that the gate mark G1 is positioned inside the recess 223 .

The first lens is inserted inside the first cylindrical portion 21 . The movement of the first lens 11 toward the object side La is restricted by covering the crimped portion 211 from the object side La. As a result, the first lens 11 is held inside the first cylindrical portion 21 . At this time, the flange surface 115 of the first annular portion 114 contacts the contact surface portion 24 from the object side La, whereby the first lens 11 is positioned in the optical axis L direction.

A first elastic member 31 is provided between the first annular portion 114 of the first lens 11 and the second annular portion 124 of the second lens 12 . In this embodiment, the first elastic member 31 is an O-ring 310 . The O-ring 310 is arranged on the outer peripheral side of the annular stepped portion 127 . The O-ring 310 is radially positioned by contacting the annular stepped portion 127 at its inner peripheral portion. The O-ring 310 overlaps the positioning stepped portion 25 when viewed from the optical axis L direction. The O-ring 310 is in close contact with the flange surface 115 of the first lens 11 and the flange surface 125 of the second lens 12 while being elastically deformed in the optical axis L direction. At this time, the first lens 11 and the second lens 12 are not in contact with each other.

As shown in FIG. 1 , a second elastic member 32 is provided between the flange surface 115 of the first lens 11 and the contact surface portion 24 outside the O-ring 310 . The second elastic member 32 is an O-ring 320 . O-ring 320 is arranged in groove 241 . The O-ring 320 is in close contact with the flange surface 115 of the first lens 11 and the bottom surface of the groove portion 241 while being elastically deformed in the optical axis L direction.

Here, the first holding force when the second lens 12 is fitted into the first portion 221 is f1, the number of lenses of the second lens 12 and the plurality of lenses is C, and the first holding force and the plurality of lenses are The third holding force, which is the sum of the second holding force when fitted to the second portion 222, is f2, the elastic force of the O-ring 310 is f3, and the first cylindrical portion 21 holds the first lens 11. Assuming that the fourth holding force is f4, the following conditional expression (1) is satisfied.
f1×C<f2<f3<f4 (1)

When the fourth holding force f4 with which the first cylindrical portion 21 holds the first lens 11 is greater than the elastic force f3 of the O-ring 310, the elastic force of the O-ring 310 is maintained even if the lens unit 1 is used for a long time. The first lens 11 does not come off from the first cylindrical portion 21 by f3. As a result, even if the lens unit 1 is used for a long time, moisture passing through the O-ring 310 can be prevented from entering the inside of the lens unit 1 .

The elastic force f3 is the sum of the first holding force f1 when the second lens 12 is fitted in the first portion 221 and the second holding force when the plurality of lenses are fitted in the second portion 222. When the third holding force f2 is larger than the third holding force f2, the cemented lens 18 is positioned via the second lens 12 and the like by the third holding force f2 when the first lens 11 is held on the first cylindrical portion 21 by caulking. It can be pressed against the stepped portion 25 . As a result, the cemented lens 18 can be reliably positioned by the positioning stepped portion 25 .

Furthermore, when the third holding force f2 is larger than the first holding force f1×the number of lenses C, the first holding force f1 is the second holding force when a plurality of lenses are fitted into the second portion 222. It is smaller than the average holding force divided by the number of sheets C. Therefore, when the first lens 11 is held by the first cylindrical portion 21 by caulking, a large force is less likely to be applied to the second lens 12, and the second lens 12 is less likely to be distorted. As a result, the O-ring 310 can evenly adhere between the first lens 11 and the second lens 12, so even if the lens unit 1 is used for a long time, the moisture passing through the O-ring 310 will Intrusion into the unit 1 can be suppressed.

In this embodiment, the first holding force f1 when the second lens 12 is fitted into the first portion 221 is 3N. The second lens 12 and the plurality of lenses are the second lens 12, the third lens 13, the fourth lens and the cemented lens 18, and the number of lenses C is four. A third holding force f2, which is the sum of the first holding force and the second holding force when the plurality of lenses are fitted to the second portion 222, is 20N. The elastic force f3 of the O-ring 310 is 30N. A fourth holding force f4 with which the first cylindrical portion 21 holds the first lens 11 is 250N. Therefore, conditional expression (1) is satisfied.

(Effect)
In this embodiment, the second lens 12 has a second annular portion 124, which is a portion where the gate marks G1 remain on the outer peripheral surface. 223 is provided with the open end facing the object side La. Therefore, since the gate trace G1 is accommodated in the recess 223, it is not necessary to form the gate trace G1 on the flat portion formed on the outer peripheral surface of the second annular portion 124. FIG. That is, there is no need to provide a flat portion on the outer peripheral surface of the second annular portion 124, and the outer diameter shape of the second annular portion 124 remains circular. Therefore, compared to the case where the gate mark is formed on the flat portion of the outer peripheral surface of the lens, it is possible to secure the contact area with which the first elastic member 31 contacts. As a result, airtightness between the first lens 11 and the second lens 12 can be ensured, so fogging of the first lens 11 can be suppressed.

In this embodiment, the first elastic member 31 is compressed between the first annular portion 114 and the second annular portion 124 to such an extent that the first lens 11 and the second lens 12 do not come into contact with each other. Therefore, compared to the case where the first lens 11 and the second lens 12 are in contact with each other, it is easier to manage the amount of compression of the first elastic member 31 . As a result, it is easy to improve the airtightness inside the lens barrel 20, so that the image-side lens surface of the first lens 11 can be prevented from being fogged. In addition, since the first lens 11 and the second lens 12 do not contact each other, when the first lens 11 is held in the first cylindrical portion 21, the first elastic member 31 is compressed, thereby It is difficult to directly apply a large force to 12 and a plurality of lenses. Therefore, when the first lens 11 is held by the first cylindrical portion 21, it is possible to prevent the lenses after the second lens 12 from being damaged.

In this embodiment, four recesses 223 are provided at equal intervals in the circumferential direction. Therefore, when the second lens 12 is press-fitted into the first portion 221 , if the center of the second lens 12 is misaligned with the optical axis L, the second lens 12 is positioned with respect to the first portion 221 . The center of the second lens 12 can be aligned with the optical axis L by rotating it about the axis L by 90°.

In this embodiment, the second annular portion 124 includes an annular stepped portion 127 that protrudes toward the object side La and can radially position the first elastic member 31 . Therefore, it is easy to position the first elastic member 31 in the radial direction. As a result, insufficient airtightness between the first lens 11 and the second lens 12 due to displacement of the first elastic member 31 can be suppressed.

In this embodiment, the third lens 13 adjacent to the second lens 12 among the plurality of lenses on the image side includes a third lens portion 133, a third annular portion 134 that surrounds the third lens portion 133, Prepare. The flange surface 135 of the third annular portion 134 facing the object side contacts the flange surface 126 of the second annular portion 124 facing the image side Lb in the direction of the optical axis L, and the bottom surface of the concave portion 223 on the image side Lb. 226 on the object side La. Therefore, the gate mark G1 does not come into contact with the bottom surface 226 of the concave portion 223, so that the third lens 13 can position the second lens 12 reliably.

In this embodiment, the inner peripheral surface of the first portion 221 is circumferentially provided with a plurality of first ribs 224 that radially position the second annular portion 124 . Therefore, even when distortion is likely to occur due to the outer shape of the lens barrel 20, the first ribs 224 can suppress the occurrence of misalignment of the second lens 12 due to the distortion of the first portion 221. can.

In this embodiment, the lens barrel 20 includes a contact surface portion 24 that contacts the first annular portion 114 from the image side Lb between the first cylindrical portion 21 and the second cylindrical portion 22 . The contact surface portion 24 includes an annular groove portion 241 recessed toward the image side Lb. An annular second elastic member 32 compressed between the first annular portion 114 and the groove portion 241 is arranged in the groove portion 241 . Therefore, it is easier to ensure airtightness between the first lens 11 and the second lens 12 .

In this embodiment, the second cylindrical portion 22 has a second portion 222 that holds a plurality of lenses. A plurality of second ribs 225 for radially positioning the plurality of lenses are provided in the circumferential direction on the inner peripheral surface of the second portion 222 . Therefore, even when distortion is likely to occur due to the outer shape of the lens barrel 20, the second ribs 225 can suppress misalignment of a plurality of lenses caused by the distortion of the second portion 222. .

In this embodiment, the lens barrel 20 includes a positioning stepped portion 25 that contacts the cemented lens 18 arranged closest to the image side among the plurality of lenses from the image side Lb. The first elastic member 31 overlaps the positioning stepped portion 25 in the optical axis L direction. Therefore, the force in the optical axis L direction when the first elastic member 31 is compressed by the first lens 11 concentrates on the positioning step portion 25 . As a result, distortion of the lens barrel 20 can be suppressed during the operation of mounting the first lens 11 .

DESCRIPTION OF SYMBOLS 1... Lens unit, 2... Light shielding sheet, 3... Diaphragm, 4... Holder, 10... Wide-angle lens, 11... First lens, 12... Second lens, 13... Third lens, 14... Fourth lens, 15... Third lens 5 lenses 15a plane portion 16 sixth lens 16a plane portion 18 cemented lens 20 lens barrel 21 first cylinder portion 22 second cylinder portion 23 outer diameter cylinder portion , 24 ... contact surface portion,
25... Positioning stepped portion 29... Recess 31... First elastic member 32... Second elastic member 111... First lens surface 112... Second lens surface 113... First lens part 114... First circle Annular portion 115 Flange surface 121 First lens surface 122 Second lens surface 123 Second lens portion 124 Second annular portion 125 Flange surface 126 Flange surface 127 Annular Stepped portion 131 First lens surface 132 Second lens surface 133 Third lens portion 134 Third annular portion 134a Flat portion 135 Flange surface 136 Flange surface 150 Flange Part 211... Crimped part 221... First part 222... Second part 223... Recessed part 224... First rib 225... Second rib 226... Bottom surface 241... Groove part 251... Overhang part 310 ... ring, 320 ... ring, G1 to G4 ... gate mark, L ... optical axis, La ... object side, Lb ... image side

Claims (9)

a first lens arranged closest to the object side along the optical axis;
A second lens made of resin arranged on the image side of the first lens;
a plurality of lenses arranged on the image side of the second lens;
a lens barrel that holds the first lens, the second lens, and the plurality of lenses;
an annular first elastic member disposed between the first lens and the second lens;
has
The first lens includes a first lens portion and a first annular portion surrounding the first lens portion,
The second lens includes a second lens portion, and a second annular portion that surrounds the second lens portion and is a portion where gate traces remain on the outer peripheral surface,
The lens barrel includes a first cylindrical portion that holds the first lens, and a second cylindrical portion that holds the second lens and the plurality of lenses radially inside the first cylindrical portion. ,
The second cylindrical portion includes a cylindrical first portion that holds the second lens,
A gate trace accommodating recess in which the gate trace is positioned inside is provided on the inner peripheral surface of the first portion with an open end facing the object side,
The lens unit, wherein the first elastic member is compressed between the first annular portion and the second annular portion to such an extent that the first lens and the second lens do not come into contact with each other. . The lens unit according to claim 1,
The inner peripheral surface of the first portion is provided with recesses at a plurality of locations in the circumferential direction,
A lens unit, wherein a part of the concave portions of the plurality of concave portions serves as the gate trace accommodating concave portion. 3. In the lens unit according to claim 1,
A lens unit in which the second lens has an annular stepped portion that protrudes toward the object side from the second annular portion and is capable of radially positioning the first elastic member. In the lens unit according to any one of claims 1 to 3,
A third lens adjacent to the second lens among the plurality of lenses on the image side includes a third lens portion and a third annular portion surrounding the third lens portion,
The surface of the third annular portion facing the object side is in contact with the surface of the second annular portion facing the image side in the optical axis direction, and is located closer to the object side than the bottom surface of the gate mark accommodating recess on the image side. A lens unit characterized in that: In the lens unit according to claim 4,
A lens unit comprising a light shielding sheet arranged between the second lens and the third lens. In the lens unit according to any one of claims 1 to 5,
A lens unit, wherein first ribs for positioning the second lens in a radial direction are provided at a plurality of locations in the circumferential direction on the inner peripheral surface of the first portion. In the lens unit according to any one of claims 1 to 6,
The lens barrel includes a contact surface portion that contacts the first annular portion from the image side between the first cylindrical portion and the second cylindrical portion,
The contact surface portion includes an annular groove recessed toward the image side,
A lens unit, wherein an annular second elastic member compressed between the first annular portion and the groove is arranged in the groove. In the lens unit according to any one of claims 1 to 7,
The second cylindrical portion includes a second portion that holds the plurality of lenses,
A lens unit, wherein second ribs for positioning the plurality of lenses in the radial direction are provided at a plurality of locations in the circumferential direction on the inner peripheral surface of the second portion. In the lens unit according to any one of claims 1 to 8,
the lens barrel includes a positioning stepped portion that abuts from the image side on the image side lens arranged closest to the image side among the plurality of lenses,
The lens unit, wherein the first elastic member overlaps the positioning step portion in the optical axis direction.

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