JP2023149437A - lens unit - Google Patents

Abstract

To provide a lens unit capable of suppressing occurrence of misting of a first lens even if air between the first lens and a second lens held by a lens barrel contains moisture.SOLUTION: A lens unit 1 includes: a first lens 2; a lens group 4; and a lens barrel 3. The lens barrel 3 includes: a first cylindrical part 21 having a holding part 24 for holding the first lens 2; a second cylindrical part 22 for housing the lens group 4 in the inner peripheral side of the first cylindrical part 21; and a connection part 23 for connecting the first cylindrical part 21 and the second cylindrical part 22 in a diametric direction. A support surface 35a provided in the connection part 23 supports the first lens 2 in a position separated from the second cylindrical part 22 and the lens group 4. The lens barrel 3 has an annular groove 36 in the outer peripheral side of the support surface 35a, and includes a through hole 40 for connecting a space S between the lens group 4 and the first lens 2 to the outside of the lens barrel 3 in the inner peripheral side of the annular groove 36 and an image side X1 of the support surface 35a. An elastic member 37 seals an area between the first lens 2 and the connection part 23.SELECTED DRAWING: Figure 3

Description

The present invention relates to a lens unit that can suppress fogging of a lens within a lens barrel.

A lens unit used in an image detection device installed in a car or a surveillance camera is described in Patent Document 1. The lens unit of the document includes a first lens, a lens group located on the image side of the first lens, and a lens barrel that holds the first lens and the lens group. A first sealing member seals between the first lens and the lens barrel. A second sealing member seals between the second lens, which is located closest to the image side among the lenses in the lens group, and the lens barrel.

Further, the lens unit of the same document includes a communication path in the lens barrel that communicates the space between the first lens and the second lens in the lens barrel with the outside of the lens barrel. The communication path is provided to prevent air in the space between the first lens and the second lens from being unable to be exhausted when the first lens is held in the lens barrel, thereby preventing assembly from becoming difficult. Therefore, when the assembly of the lens unit is completed, the communication path is closed by the third sealing member.

JP2021-157150A

In the above lens unit, the space between the first lens and the second lens is isolated from the outside by the first sealing member, the second sealing member, and the third sealing member. Therefore, water does not enter this space from outside the lens barrel. However, when the assembly of the lens unit is completed, if there is air containing moisture in the space between the first lens and the second lens, the object side surface of the first lens may Cloudiness may occur.

In view of the above problems, when the first lens and the second lens are held in the lens barrel, even if the air between the first lens and the second lens contains moisture, the first lens An object of the present invention is to provide a lens unit that can prevent or suppress the occurrence of fogging.

In order to solve the above problems, the lens unit of the present invention includes a first lens, a lens group located on the image side of the first lens, and a first cylinder having a holding portion that holds the first lens from the outer peripheral side. a second cylindrical portion located on the image side of the first lens and holding the lens group from the outer peripheral side on the inner peripheral side of the first cylindrical portion; The lens barrel includes an annular connecting portion that connects the first cylindrical portion and the second cylindrical portion in the radial direction, and an annular elastic member, and the connecting portion connects the outer peripheral edge portion of the first lens. a first lens support portion having a support surface for supporting from the image side, the support surface supporting the first lens at a position spaced apart from the second cylinder portion and the lens group toward the object side; is provided with an annular groove recessed toward the image side on the outer circumference side of the support surface, and is located on the inner circumference side of the annular groove, closer to the image side than the support surface, and closest to the object side of the lens group. a through hole that communicates a space between the second lens and the first lens with a space outside the second cylindrical portion on the image side of the connecting portion; The first lens may be disposed in the groove to seal between the first lens and the connecting portion.

According to the present invention, the lens barrel includes a space between the first lens and the second lens held in the lens barrel, and a space outside the second barrel portion on the image side of the connecting portion of the lens barrel. A through hole is provided to communicate with each other. Therefore, even if the air in this space contains moisture, the humid air can escape to the space outside the second barrel part on the image side of the lens barrel connection part through the through hole. can. Therefore, it is possible to prevent or suppress the occurrence of fogging on the image side surface of the first lens.

In the present invention, the lens barrel may be made of amorphous resin. Amorphous resins have better water absorption than crystalline resins. Therefore, if the air in the space contains moisture, this moisture can be absorbed by the lens barrel. Therefore, it is easy to prevent fogging from occurring on the first lens.

In the present invention, the first cylindrical portion includes an annular skirt portion facing the second cylindrical portion with a gap in the radial direction on the image side of the connecting portion, and the through hole The through hole may be provided in the connecting portion, and may communicate the space with a gap between the skirt portion and the second cylindrical portion.

In this case, the second cylindrical portion includes an annular portion including a tapered outer circumferential surface that slopes inward toward the object at the object-side end; a bent portion that is bent toward the inner peripheral side and abuts the outer peripheral edge of the second lens from the object side, and one end opening of the through hole is formed on the surface of the connecting portion facing the image side. , provided at a position overlapping with the support surface when viewed from the optical axis direction, the other end opening of the through hole is provided in the first lens support portion, and has a diameter on the tapered outer peripheral surface of the annular portion. They may face each other from the outside. In this way, compared to the case where the through hole is provided inside the first lens support portion in the connecting portion, it is possible to suppress the connecting portion from becoming larger in the radial direction.

In the present invention, the through hole may include a first through hole and a second through hole provided at positions separated by 180 degrees around the optical axis. In this way, when the lens unit is used with the optical axis horizontal, the first through hole can be located above the space, and the second through hole can be located below the space. Therefore, using the convection current generated due to the temperature of the outside air, air containing moisture can be released from the first through hole to the outside.

In the present invention, the second cylindrical portion includes a bent portion that is bent from the object-side end to the inner circumferential side and comes into contact with the outer circumferential edge of the second lens from the object side, and a bent portion that protrudes toward the inner circumferential side and contacts the outer circumferential edge of the second lens from the object side. a support portion that supports the group from the image side, the bent portion includes a notch in a portion in the circumferential direction, and the support portion overlaps the notch when viewed from the optical axis direction. The through hole is provided at the inner peripheral surface of the second cylindrical portion, and the inner peripheral surface portion between the bent portion and the support portion is provided with the notch and the through hole extending in the optical axis direction. A communication groove may be provided to allow communication between the two. In this way, when the air in the space between the first lens and the second lens held in the lens barrel contains moisture, this air can be discharged to the image side of the second barrel portion.

In the present invention, the second cylindrical portion includes a bent portion that is bent from the object-side end to the inner circumferential side and comes into contact with the outer circumferential edge of the second lens from the object side, and a bent portion that protrudes toward the inner circumferential side and contacts the outer circumferential edge of the second lens from the object side. a support part that supports the group from the image side, and the second cylinder part has an inner peripheral surface part between the bent part and the support part on the inner peripheral surface of the second cylinder part, The plurality of ribs are arranged in the circumferential direction and abut on the lens group from the outer peripheral side to position the lens group in the radial direction. When viewed from the axial direction, a notch is provided at a position that overlaps with a gap between the ribs that are adjacent to each other in the circumferential direction; The through hole may be provided at a position overlapping with the through hole, and the gap may be a communication groove that communicates the notch and the through hole in the optical axis direction. In this way, by utilizing the plurality of ribs that position the lens group in the radial direction inside the second barrel, the space between the first lens and the second lens held in the barrel and the With the hole,
It can be communicated. Therefore, when the air in the space between the first lens and the second lens held in the lens barrel contains moisture, this air can be discharged to the image side of the second barrel.

In the present invention, the notch includes a first notch and a second notch provided at positions 180 degrees apart around the optical axis, and the through hole includes the first notch when viewed from the optical axis direction. a first through hole that overlaps with the first notch, and a second through hole that overlaps with the second notch, and the communication groove extends in the optical axis direction and connects the first notch and the first through hole. It may be provided with a first communication groove that communicates with each other, and a second communication groove that extends in the optical axis direction and allows the second notch and the second through hole to communicate with each other. In this way, when the lens unit is used with the optical axis horizontal, the first notch, the first communication groove, and the first through hole are positioned above the space, and the second notch, The second communication groove and the second through hole can be located below the space. Therefore, using the convection current generated due to the temperature of the outside air, air containing moisture can be released from the first through hole to the outside.

According to the present invention, the lens barrel includes a space between the first lens and the second lens held in the lens barrel, and a space outside the second barrel portion on the image side of the connecting portion of the lens barrel. A through hole is provided for communication. Therefore, even if the air in the space contains moisture, the humid air can be released to the outside of the lens barrel through the through hole. Therefore, it is possible to prevent or suppress the occurrence of fogging on the image side surface of the first lens.

FIG. 1 is an external perspective view of a lens unit to which the present invention is applied. FIG. 2 is a cross-sectional view taken along line AA in FIG. 1. 2 is a sectional view taken along line BB in FIG. 1. FIG. FIG. 3 is an exploded perspective view of the lens unit. FIG. 3 is a perspective view of the lens barrel viewed from the image side. FIG. 3 is a perspective view of a lens unit of Example 2. 7 is a sectional view taken along line DD in FIG. 6. FIG. FIG. 3 is an exploded perspective view of a lens unit of Example 2. FIG. 7 is a plan view of the lens barrel of the lens unit of Example 2 when viewed from the object side. FIG. 7 is a perspective view of the lens barrel of the lens unit of Example 2 when viewed from the image side.

Hereinafter, embodiments of a lens unit to which the present invention is applied will be described with reference to the drawings.

(Example 1)
FIG. 1 is an external perspective view of a lens unit to which the present invention is applied. FIG. 2 is a cross-sectional view taken along line AA in FIG. FIG. 3 is a sectional view taken along line BB in FIG. FIG. 4 is an exploded perspective view of the lens unit. FIG. 5 is a perspective view of the lens barrel viewed from the image side. The lens unit 1 of this example is used in an imaging device mounted on a car or a surveillance camera.

(Optical system)
As shown in FIG. 1, the lens unit 1 includes a first lens 2 and a lens barrel 3. Further, as shown in FIGS. 2 to 4, the lens unit 1 is held in the lens barrel 3 on the image side X1 of the first lens 2 in the optical axis direction X along the optical axis L of the first lens 2. It has a lens group 4. The lens group 4 includes a second lens 5, a third lens 6, a fourth lens 7, and a fifth lens 8 in the optical axis direction X from the object side to the image side X1. The fifth lens 8 is a cemented lens made by cementing two lenses. Each lens constituting the lens group 4 has a smaller outer diameter than the first lens 2. The lens unit 1 also includes an annular light-shielding sheet 9 disposed between the second lens 5 and the third lens 6, and an annular light-shielding sheet 9 disposed between the third lens 6 and the fourth lens 7. A diaphragm 10 is provided.

The first lens 2 is made of resin or glass. The first lens 2 is a meniscus lens. As shown in FIG. 2, the first lens 2 includes a curved surface on the object side X2 that projects toward the object side X2. The first lens 2 also has a curved surface 2a recessed toward the image side X1 and the object side X2, and an annular flange surface 2b (outer peripheral edge portion) that extends in a direction perpendicular to the optical axis L on the outer peripheral side of the curved surface. , is provided. The flange surface 2b is coated with black ink for light shielding.

The second lens 5 is made of resin. The second lens 5 is a meniscus lens. The second lens 5 includes a curved surface protruding toward the object side X2 on the object side X2, and a curved surface concave toward the object side X2 on the image side X1. The third lens 6 is made of resin. The third lens 6 includes a curved surface on the object side X2, which is the object side X2, and a curved surface on the image side X1, which projects toward the image side X1. The fourth lens 7 is made of glass. The fourth lens 7 has a smaller outer diameter than the second lens 5, the third lens 6, and the fifth lens 8. The fourth lens 7 is located between the third lens 6 and the fifth lens 8 while being held by the annular holder 11 .

The fifth lens 8 includes an object side lens 13 and an image side lens 14 located on the image side X1 of the object side lens 13. Both the object side lens 13 and the image side lens 14 are made of resin. The object side lens 13 includes a curved surface on the object side X2 that curves toward the image side X1, and a curved surface that is concave toward the object side X2 on the image side X1. The image side lens 14 includes a curved surface protruding toward the object side X2 on the object side X2, and a curved surface protruding toward the image side X1 on the image side X1. The image side lens 14 is cemented to the object side lens 13 with a curved surface protruding toward the object side X2 inserted into a curved surface of the object side lens 13 recessed toward the object side X2. The outer diameter of the object side lens 13 is smaller than the outer diameter of the image side lens 14. Therefore, the object side lens 13 includes an annular flange portion 13a located on the outer peripheral side of the image side lens 14 when viewed from the optical axis direction X.

Here, as shown in FIG. 4, the second lens 5, the third lens 6, the fourth lens 7, the fifth lens 8, and the holder 11 are arranged in a part of the circumferential direction when viewed from the optical axis direction A notch 16 is provided that extends linearly in the circumferential direction. The holder 11 holding the second lens 5, the third lens 6, and the fourth lens 7, and the fifth lens 8 are stacked with the cutout portions 16 arranged at the same angular position around the optical axis L.

(lens barrel)
The lens barrel 3 is made of resin. In this example, the lens barrel 3 is made of amorphous resin. The lens barrel 3 is made of polycarbonate.

As shown in FIG. 2, the lens barrel 3 includes a first cylindrical portion 21, a second cylindrical portion 22 located on the inner peripheral side of the first cylindrical portion 21, and a middle portion of the first cylindrical portion 21 in the optical axis direction X. It has a connecting part 23 that protrudes radially inward from and connects the first cylindrical part 21 and the second cylindrical part 22 in the radial direction. The first cylindrical portion 21 has a holding portion 24 on the object side X2 of the connecting portion 23 that holds the first lens 2 from the outer peripheral side. Further, the first cylindrical portion 21 has a skirt portion 25 on the image side X1 of the connecting portion 23 that surrounds the second cylindrical portion 22 from the outer peripheral side. Further, the first cylindrical portion 21 includes, at the end of the object side X2, a first bent portion 26 that is bent toward the inner circumferential side and abuts the outer circumferential edge of the first lens 2 from the object side X2. Note that the first bent portion 26 is provided by caulking the end of the first cylindrical portion 21 on the object side X2.

The second cylindrical portion 22 accommodates the lens group 4 on the inner peripheral side. The second cylindrical portion 22 includes an annular portion 28 provided with a tapered outer circumferential surface 28a that slopes inward toward the object side X2 at an end on the object side The second bent portion 29 is bent toward the side and abuts the outer peripheral edge of the second lens 5 from the object side X2. The second cylindrical portion 22 also includes an annular support portion 30 that protrudes radially inward from the image side X1 portion and supports the lens group 4.

The support portion 30 contacts the flange portion 13a of the object-side lens 13 of the fifth lens 8 from the image side X1, and supports the lens group 4 from the image side X1. Further, the support portion 30 includes an annular plate portion 31 that protrudes radially inward from the end portion on the object side X2. The inner peripheral edge of the annular plate portion 31 defines a circular opening 32 . Here, the support portion 30 and the annular plate portion 31 are not in contact with the image side lens 14 of the fifth lens 8. That is, the support portion 30 faces the image side lens 14 with a gap in the radial direction. The annular plate portion 31 corresponds to the image side lens 14 with a gap in the optical axis direction X. An image sensor (not shown) is fixed to the annular plate portion 31 from the image side X1. The imaging device blocks the circular aperture 32. Here, the second bent portion 29 is provided by caulking the end of the second cylindrical portion 22 on the object side X2. The second bent portion 29 and the support portion 30 hold the lens group 4 from both sides in the optical axis direction X.

Further, as shown in FIG. 4, the second cylindrical portion 22 includes a plurality of ribs 33 extending in the optical axis direction X between the second bent portion 29 and the support portion 30 on the inner circumferential surface. The plurality of ribs 33 are arranged in the circumferential direction. Each rib 33 is connected to the holder 11 that holds the second lens 5, third lens 6, and fourth lens 7, and the object side lens of the fifth lens 8 when the lens group 4 is housed in the second cylindrical portion 22. 13 from the outside in the radial direction to position the lens group 4 in the radial direction.

Here, between the holder 11 holding the second lens 5, the third lens 6, and the fourth lens 7, and the fifth lens 8 and the second cylindrical part 22, a notch 16 provided therein is provided. , a gap extending in the optical axis direction X is formed. Moreover, between the holder 11 that holds the second lens 5, the third lens 6, and the fourth lens 7, and the fifth lens 8 and the second cylindrical portion 22, there is a gap between ribs 33 that are adjacent to each other in the circumferential direction. , a gap extending in the optical axis direction X is formed.

As shown in FIG. 2, the connecting portion 23 includes a first lens support portion 35 having a support surface 35a that supports the flange surface 2b of the first lens 2 from the image side X1. The support surface 35a supports the first lens 2 at a position spaced apart from the second cylinder portion 22 and the lens group 4 toward the object side X2. The first bent portion 26 and the support surface 35a hold the first lens 2 from both sides in the optical axis direction X.

Here, the lens barrel 3 includes an annular groove 36 recessed toward the image side X1 on the outer peripheral side of the support surface 35a. An annular elastic member 37 is inserted into the annular groove 36 . The elastic member 37 is elastically deformed in the optical axis direction X and seals between the first lens 2 and the connecting portion 23 . The lens barrel 3 also has a space S between the second lens 5 and the first lens 2 on the inner peripheral side of the annular groove 36 and on the image side of the support surface 35a, and on the image side of the connecting part 23. A through hole 38 is provided at X1 to communicate with the space outside the second cylindrical portion 22.

The through hole 38 is provided so as to penetrate the connecting portion 23 in the optical axis direction X. In addition, as shown in FIGS. 3 and 5, in this example, the first through hole 38 (1) and the second through hole 38 ( 2). As can be seen from FIG. 3, the end opening 38a on the image side X1 of each through hole 38 is located at a position that overlaps with the support surface 35a when viewed from the optical axis direction It is provided. As shown in FIG. 5, the end opening 38b of each through hole 38 on the object side It faces the surface 28a from the outside in the radial direction. Each through hole 38 widens in the circumferential direction toward the end opening 38a on the image side X1.

(effect)
According to this example, the lens barrel 3 includes a space between the first lens 2 and the second lens 5 held in the lens barrel 3, and a second lens located on the image side X1 with respect to the connecting portion 23 of the lens barrel 3. A through hole 38 is provided to communicate the space outside the cylindrical portion 22. This through hole 38 is not sealed with a sealant or the like. Therefore, even if the air in the space contains moisture, the humid air is pumped through the through hole 38 into the space outside the second cylinder part 22 on the image side X1 relative to the connecting part 23 of the lens barrel 3. can be released to Therefore, it is possible to prevent or suppress the occurrence of fogging on the image side X1 surface of the first lens 2.

Further, in this example, the through hole 38 includes a first through hole 38 (1) and a second through hole 38 (2) provided at positions 180 degrees apart around the optical axis L. Therefore, when the lens unit 1 is used with the optical axis L horizontally, the first through hole 38 (1) is positioned above the space S, and the second through hole 38 (2) is positioned below the space S. It can be placed on the side. Therefore, the air containing moisture can escape to the outside from the first through hole 38(1) by using convection generated due to the temperature of the outside air.

Furthermore, the end portion of the second cylindrical portion 22 on the object side A second bent portion 29 is bent toward the circumferential side and abuts on the outer peripheral edge of the second lens 5 from the object side X2. The end opening 38a on the image side X1 of the through hole 38 is provided at a position that overlaps with the support surface 35a when viewed from the optical axis direction The end opening 38b on the side X2 is provided on the radially inward surface of the first lens support portion 35 and faces the tapered outer peripheral surface 28a of the annular portion 28 from the radially outside. Therefore, compared to the case where the through hole 38 is provided on the inner peripheral side of the first lens support portion 35, it is possible to suppress the connection portion 23 from increasing in size in the radial direction.

In this example, the lens barrel 3 is made of amorphous resin. Amorphous resins have better water absorption than crystalline resins. Therefore, if the air in the space S contains moisture, this moisture can be absorbed by the lens barrel 3. Therefore, it is easy to prevent the first lens 2 from becoming cloudy.

(Example 2)
FIG. 6 is a perspective view of the lens unit of Example 2. FIG. 7 is a sectional view taken along the line DD in FIG. 6. FIG. 8 is an exploded perspective view of the lens unit of Example 2. FIG. 9 is a plan view of the lens barrel of the lens unit of Example 2 when viewed from the object side X2. FIG. 10 is a perspective view of the lens barrel of the lens unit of Example 2 when viewed from the image side X1. As shown in FIG. 6, the lens unit 1A of this example has the same external shape as the lens unit 1. Further, the sectional view taken along line CC in FIG. 6 is the same as the sectional view taken along line AA of the lens unit 1 shown in FIG. Here, in the lens unit 1A of this example, the structure of the lens barrel 3A is different from the lens barrel 3 of the lens unit 1b, but the structure of the optical system is the same as that of the lens unit 1. Therefore, only the lens barrel 3 will be explained, and other explanations will be omitted. Further, the lens barrel 3A of the lens unit 1A has a configuration corresponding to the lens barrel 3 of the lens unit 1. Therefore, corresponding configurations are given the same reference numerals and their explanations will be omitted.

(lens barrel)
The lens barrel 3A is made of amorphous resin. As shown in FIGS. 2 and 7, the lens barrel 3A includes a first cylindrical portion 21, a second cylindrical portion 22 located on the inner peripheral side of the first cylindrical portion 21, and an optical axis direction of the first cylindrical portion 21. It has a connecting part 23 that protrudes radially inward from the middle of the X and connects the first cylindrical part 21 and the second cylindrical part 22 in the radial direction. The first cylindrical portion 21 has a holding portion 24 on the object side X2 of the connecting portion 23. Further, the first cylindrical portion 21 has a skirt portion 25 on the image side X1 of the connecting portion 23. Further, the first cylindrical portion 21 includes, at the end of the object side X2, a first bent portion 26 that is bent toward the inner circumferential side and abuts the outer circumferential edge of the first lens 2 from the object side X2.

The second cylindrical portion 22 accommodates the lens group 4 inside. The second cylindrical portion 22 includes an annular portion 28 provided with a tapered outer circumferential surface 28a that slopes inward toward the object side X2 at an end on the object side The second bent portion 29 is bent toward the side and abuts the outer peripheral edge of the second lens 5 from the object side X2. The second cylindrical portion 22 also includes an annular support portion 30 that protrudes radially inward from the image side X1 portion and supports the lens group 4. The support portion 30 includes an annular plate portion 31 that protrudes radially inward from an end portion on the object side X2. The inner peripheral edge of the annular plate portion 31 defines a circular opening 32 .

Here, as shown in FIGS. 8 and 9, the second bent portion 29 of the second cylindrical portion 22 includes a radial notch 41 in a portion in the circumferential direction. In this example, the notch 41 includes a first notch 41(1) and a second notch 41(2) provided at two locations 180 degrees apart around the optical axis L. Further, as shown in FIGS. 8, 9, and 10, the support portion 30 includes a circular through hole 40 at a position overlapping the notch 41 when viewed from the optical axis direction X. In this example, the through holes 40 include a first through hole 40 (1) that overlaps with the first notch 41 (1) when viewed from the optical axis direction X, and a second through hole that overlaps with the second notch 41 (2). A through hole 40(2) is provided. Furthermore, as shown in FIG. 8, a notch 41 is formed on the inner circumferential surface 34 of the second cylindrical portion 22 and extends in the optical axis direction X between the second bent portion 29 and the support portion 30. A communication groove 42 is provided that communicates the through hole 40 with the through hole 40 . The cross section of the communication groove 42 is arcuate. In this example, as the communication groove 42, a first communication groove 42(1) that extends in the optical axis direction X and communicates the first notch 41(1) and the first through hole 40(1), and A second communication groove 42(2) extending in the direction X and communicating the second notch 41(2) and the second through hole 40(2) is provided.

Further, the second cylindrical portion 22 includes a plurality of ribs 33 extending in the optical axis direction X between the second bent portion 29 and the support portion 30 on the inner circumferential surface 34 . The plurality of ribs 33 are arranged in the circumferential direction. Each rib 33 is connected to the holder 11 that holds the second lens 5, third lens 6, and fourth lens 7, and the object side lens of the fifth lens 8 when the lens group 4 is housed in the second cylindrical portion 22. 13 from the outside in the radial direction to position the lens group 4 in the radial direction. A notch 16 provided in the holder 11 holding the second lens 5, third lens 6, and fourth lens 7 and the fifth lens 8 and the second cylindrical portion 22 allows the optical axis to be A gap extending in direction X is formed. Moreover, between the holder 11 that holds the second lens 5, the third lens 6, and the fourth lens 7, and the fifth lens 8 and the second cylindrical portion 22, there is a gap between ribs 33 that are adjacent to each other in the circumferential direction. , a gap extending in the optical axis direction X is formed.

Here, in this example, the notch 41 is provided at a position overlapping the rib 33 when viewed from the optical axis direction X. Therefore, the first communication groove 42 (1) and the second communication groove 42 (2) are provided in two ribs 33 located at opposing positions with the optical axis L in between, and each rib 33 is provided in two in the circumferential direction. It is divided into Note that the radial depth dimension of the first communication groove 42 (1) and the second communication groove 42 (2) is larger than the radial height dimension of each rib 33. Here, the notch 41, the communication groove 42, and the through hole 40 may be located between the ribs 33 in the circumferential direction. That is, the communication groove 42 may be formed in the inner circumferential surface 34 between the ribs 33 in the second cylindrical portion 22 .

The connecting portion 23 includes a first lens support portion 35 having a support surface 35a. The support surface 35a supports the first lens 2 at a position spaced apart from the second cylinder portion 22 and the lens group 4 toward the object side X2. The first bent portion 26 and the support surface 35a hold the first lens 2 from both sides in the optical axis direction X.

Further, the lens barrel 3A includes an annular groove 36 recessed toward the image side X1 on the outer peripheral side of the support surface 35a. An annular elastic member 37 is inserted into the annular groove 36 . The elastic member 37 is elastically deformed in the optical axis direction X and seals between the first lens 2 and the connecting portion 23 . Further, the lens barrel 3A is located on the inner peripheral side of the annular groove 36 and on the image side of the support surface 35a, and the space S between the second lens 5 and the first lens 2, and on the image side of the connecting portion 23. A through hole 40 is provided at X1 to communicate with the space outside the second cylindrical portion 22.

(effect)
According to this example, the space S between the first lens 2 and the second lens 5 held in the lens barrel 3A is formed by a notch 41 provided in the second bent portion 29 of the second cylinder portion 22, It communicates with the outside of the lens unit 1 via a communication groove 42 provided in the inner circumferential surface 34 of the cylindrical portion 22 and a through hole 40 . Therefore, even if the air in the space S contains moisture, the humid air is transferred to the outside of the second cylinder part 22 on the image side X1 with respect to the connection part 23 of the lens barrel 3A through the through hole 40. It can be released into space. Therefore, it is possible to prevent or suppress the occurrence of fogging on the image side X1 surface of the first lens 2.

In addition, in this example, the first notch 41(1), the first communication groove 42(1), and the first through hole 40(1) provided at positions 180 degrees apart around the optical axis L, and the second It includes a notch 41(2), a second communication groove 42(2), and a second through hole 40(2). Therefore, when the lens unit 1 is used with the optical axis L horizontally, the first notch 41 (1), the first communication groove 42 (1) and the first through hole 40 (1) are arranged in the space S. The second notch 41(2), the second communication groove 42(2), and the second through hole 40(2) can be located on the lower side of the space S. Therefore, the air containing moisture can escape to the outside from the first through hole 40(1) by using convection generated due to the temperature of the outside air.

Further, the lens barrel 3A is made of amorphous resin. Amorphous resins have better water absorption than crystalline resins. Therefore, if the air in the space S contains moisture, this moisture can be absorbed by the lens barrel 3A. Therefore, the occurrence of clouding on the first lens 2 can be further suppressed.

Note that when the notch 41 provided in the second bent portion 29 of the second cylindrical portion 22 is provided at a position overlapping the gap between the ribs 33 when viewed from the optical axis direction X, the rib 33 The gap between the rib 33 and the rib 33 may be used as a communication groove. In this case, if the through hole 40 is provided at a position overlapping the notch 41 when viewed from the optical axis direction X, the gap between the ribs 33 in the circumferential direction will This becomes a communication groove that communicates in the direction X. Therefore, the air in the space S can be released to the outside through the notch 41, the gap between the ribs 33, and the through hole 40.

1.1A...lens unit, 2...first lens, 2a...curved surface, 2b...flange surface, 3.3A...lens barrel, 4...lens group, 5...second lens, 6...third lens, 7...th 4 lenses, 8...Fifth lens, 9...Light shielding sheet, 10...Aperture, 11...Holder, 13...Object side lens, 13a...Flange part, 14...Image side lens, 16...Notch part, 21...First cylinder Part, 22... Second cylindrical part, 23... Connecting part, 24... Holding part, 25... Skirt part, 26... First bending part, 28... Annular part, 28a... Tapered outer peripheral surface, 29... Second bending part, 30 ... Supporting portion, 31... Annular plate portion, 32... Circular opening, 33... Rib, 34... Inner peripheral surface, 35... First lens supporting portion, 35a... Supporting surface, 36... Annular groove, 37... Elastic member, 38... Through hole, 38a... End opening, 38b... End opening, 40... Through hole, 41... Notch, 42... Communication groove, L... Optical axis

Claims (8)

a first lens;
a lens group located on the image side of the first lens;
a first cylindrical portion having a holding portion that holds the first lens from an outer peripheral side; a first cylindrical portion that is located on the image side of the first lens; and a first cylindrical portion that holds the lens group from the outer periphery on an inner peripheral side of the first cylindrical portion; a lens barrel including a second cylindrical portion and an annular connecting portion radially connecting the first cylindrical portion and the second cylindrical portion on the image side of the holding portion;
an annular elastic member;
The connecting portion includes a first lens support portion having a support surface that supports an outer peripheral edge portion of the first lens from the image side,
The support surface supports the first lens at a position spaced from the second cylinder portion and the lens group toward the object side,
The lens barrel includes an annular groove recessed toward the image side on the outer peripheral side of the support surface, and an annular groove recessed toward the image side than the annular groove and on the image side of the support surface, the most object side of the lens group. a through hole that communicates a space between the second lens and the first lens located in the second lens with a space outside the second cylindrical part on the image side of the connecting part,
The lens unit is characterized in that the elastic member is disposed in the annular groove to seal between the first lens and the connecting portion. The lens unit according to claim 1, wherein the lens barrel is made of amorphous resin. The first cylindrical portion includes an annular skirt portion facing the second cylindrical portion with a gap in the radial direction on the image side of the connecting portion,
The through hole is provided in the connection part,
The lens unit according to claim 1 or 2, wherein the through hole communicates the space with a gap between the skirt portion and the second cylinder portion. The second cylindrical portion includes an annular portion including a tapered outer circumferential surface that slopes inward toward the object at the object-side end, and an annular portion that extends inward from the object-side end of the annular portion. a bent portion that is bent and abuts the outer peripheral edge of the second lens from the object side;
One end opening of the through hole is provided in a surface of the connecting portion facing the image side at a position that overlaps with the supporting surface when viewed from the optical axis direction,
4. The lens unit according to claim 3, wherein the other end opening of the through hole is provided in the first lens support portion and faces the tapered outer circumferential surface of the annular portion from the outside in the radial direction. 5. The lens unit according to claim 3, wherein the through hole includes a first through hole and a second through hole provided at positions separated by 180 degrees around the optical axis. The second cylindrical portion has a bent portion that is bent from the object-side end toward the inner circumference and abuts the outer circumferential edge of the second lens from the object side, and a bent portion that protrudes toward the inner circumference to move the lens group toward the image. a support portion that supports from the side;
The bent portion includes a notch in a portion in the circumferential direction,
The support portion includes the through hole at a position overlapping the notch when viewed from the optical axis direction,
A communication groove that extends in the optical axis direction and communicates the notch and the through hole is provided in an inner circumferential surface portion of the second cylindrical portion between the bent portion and the support portion. The lens unit according to any one of claims 1 to 3, characterized in that: The second cylindrical portion has a bent portion that is bent from the object-side end toward the inner circumference and abuts the outer circumferential edge of the second lens from the object side, and a bent portion that protrudes toward the inner circumference to move the lens group toward the image. a support portion that supports from the side;
The second cylindrical portion includes a plurality of ribs extending in the optical axis direction on an inner peripheral surface portion of the second cylindrical portion between the bent portion and the support portion,
The plurality of ribs are arranged in a circumferential direction and contact the lens group from an outer peripheral side to position the lens group in the radial direction,
The bent portion includes a notch at a position that overlaps with a gap between the ribs that are adjacent to each other in the circumferential direction when viewed from the optical axis direction,
The support portion includes the through hole at a position overlapping the notch when viewed from the optical axis direction,
The lens unit according to any one of claims 1 to 3, wherein the gap is a communication groove that allows the notch and the through hole to communicate in the optical axis direction. The notch includes a first notch and a second notch provided at positions separated by 180° around the optical axis,
The through hole includes a first through hole that overlaps with the first notch when viewed from the optical axis direction, and a second through hole that overlaps with the second notch,
The communication groove includes a first communication groove that extends in the optical axis direction and connects the first notch and the first through hole, and a first communication groove that extends in the optical axis direction and connects the second notch and the second through hole. The lens unit according to claim 6 or 7, further comprising a second communication groove that communicates with the through hole.

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