JP2024000240A - lens unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens unit that can easily fix a first lens barrel and a second lens barrel each other by laser welding even when a first lens barrel member and second lens barrel member are formed by optical absorptivity resin.

SOLUTION: A lens unit 1 has: a first lens barrel member 21 that holds a first lens 2; a second lens barrel member 22 that holds a lens group 4; a connecting member 23 that connects the first lens barrel member 21 and the second lens barrel member 22; a first fixation part 41 that fixes the first lens barrel member 21 and the connecting member 23; and a second fixation part 42 that fixes the second lens barrel member 22 and the connecting member 23. The first lens barrel member 21 and the second lens barrel member 22 are made of resin including optical absorptivity. The connecting member 23 is made of resin including optical transmissivity. The first lens barrel member 21 and the connecting member 23 are subjected to laser welding, thereby the first fixation part 41 is formed.

SELECTED DRAWING: Figure 2

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to a lens unit whose lens barrel is composed of two lens barrel members.

A lens unit used in an imaging device installed in a car or a surveillance camera is described in Patent Document 1. The lens unit of the same document includes a first lens located on the object side, a lens group located on the image side of the second lens, and a lens barrel that holds the first lens and the second lens. The lens barrel includes an annular inner frame member and an annular outer frame member surrounding the inner frame member from the outer periphery. The inner frame member includes a cylindrical portion and a flange portion that protrudes toward the outer circumferential side from the object-side end portion of the cylindrical portion. The outer frame member includes an annular stepped portion that supports the flange portion from the image side while penetrating the inner frame member. The lens group is housed on the inner peripheral side of the inner frame member. The first lens is held from the outer peripheral side by the outer frame member, and is supported from the image side by the flange of the inner frame member.

JP 2021-5019 Publication

When assembling the above lens unit, the lens group is housed in the inner frame member, the inner frame member is then supported by the annular stepped portion of the outer frame member, and then the first lens is attached to the outer frame member. While holding it, it is locked to the flange of the inner frame member. Therefore, in the manufacturing process of the lens unit, the step of holding the first lens on the outer frame member cannot be performed until after the step of holding the lens group on the inner frame member.

Therefore, the first lens barrel member that holds the first lens and the second lens barrel member that holds the lens group located on the inner circumferential side of the first lens barrel member and on the image side of the first lens are separated. It is possible that In this way, when manufacturing the lens unit, the holding of the first lens to the first lens barrel member and the holding of the lens group to the second lens barrel member can be performed separately and independently. Then, one lens unit is manufactured by fixing the first lens barrel member and the second lens barrel member to each other. In this case, the first lens barrel member and the second lens barrel member are formed of light-absorbing resin in order to suppress ghosts and flares from occurring in the lens unit due to the influence of strong light from the outside.

Here, methods for fixing the first lens barrel member and the second lens barrel member to each other include fixing with adhesive, fixing with vibration welding, and fixing with laser welding. When fixed with adhesive, outgas is generated when the adhesive hardens. When this outgas remains inside the lens unit, there is a problem in that lens performance deteriorates. If the lenses are fixed by vibration welding, the lenses held by the first lens barrel member and the second lens barrel member may be affected by the vibrations caused by the vibrations during the fixing, and the lens performance may deteriorate. Therefore, in consideration of the reliability and lens performance of the lens unit, it is desirable to use laser welding as the fixing method. However, if the first lens barrel member and the second lens barrel member are formed of light-absorbing resin, it is possible to fix the first lens barrel member and the second lens barrel member to each other by laser welding. However, it is not easy to laser weld light-absorbing resins together, and there is a problem that the welding strength is low when laser welding is performed.

In view of the above problems, the problem of the present invention is that even if the first lens barrel member and the second lens barrel member are formed of light-absorbing resin, the first lens barrel member and the second lens barrel member can be formed by laser welding. An object of the present invention is to provide a lens unit in which two lens barrel members can be easily fixed to each other.

In order to solve the above problems, the lens unit of the present invention includes a first lens barrel member that holds a first lens, and a lens group located on the inner peripheral side of the first lens barrel member and on the image side of the first lens. a second lens barrel member that holds the lens barrel, a connecting member that connects the first lens barrel member and the second lens barrel member, and a first fixing portion that fixes the first lens barrel member and the connecting member; , a second fixing part that fixes the second lens barrel member and the connecting member, the first lens barrel member and the second lens barrel member are made of a resin having light absorbing properties, The connecting member is made of a light-transmitting resin, and the first fixing portion is formed by laser welding the first lens barrel member and the connecting member.

According to the present invention, the first lens is held by the first lens barrel member, and the lens group located on the image side of the first lens is held by the second lens barrel member. Therefore, when manufacturing the lens unit, it is possible to separately hold the first lens to the first lens barrel member and to hold the lens group to the second lens barrel member.

Further, the first lens barrel member and the second lens barrel member are made of resin having light absorbing properties. Therefore, it is possible to suppress ghosts and flares from occurring in the lens unit due to the influence of strong light from the outside.

Further, the first lens barrel member and the second lens barrel member are connected via a connecting member. At this time, the first lens barrel member and the connecting member are fixed by the first fixing part. The second lens barrel member and the connecting member are fixed by the second fixing part. Here, the connecting member is made of a resin having light transmittance. In this way, the first fixing part can be easily formed by laser welding the first lens barrel member and the connecting member. Therefore, since the first fixing part is not formed with adhesive, there is no risk that outgas generated from the adhesive will stay inside the lens unit and deteriorate the lens performance of the lens unit. Furthermore, since the first fixing portion is not formed by vibration welding, there is no risk that the lens performance of the lens unit will deteriorate during welding. Further, since the characteristics of the resin materials of the first lens barrel member and the connecting member are different, it is easy to laser weld the first lens barrel member and the connecting member, and the welding strength when laser welding is increased.

In the present invention, the connecting member may be made of the same resin as one of the first lens barrel member and the second lens barrel member.

In the present invention, it is preferable that the connecting member is made of the same resin as the first lens barrel member. In this way, since the connecting member and the first lens barrel member are made of the same resin, the welding strength between the connecting member and the first lens barrel member can be increased.

In the present invention, it is preferable that the first lens barrel member is made of a crystalline resin having the light-absorbing property, and that the second lens-barrel member is made of an amorphous resin having the light-absorbing property. In this way, the weather resistance of the first lens barrel member can be increased compared to the case where the first lens barrel member is made of amorphous resin. Therefore, when the lens unit is installed in a vehicle-mounted imaging device or an imaging device installed outdoors, it is possible to suppress the first lens barrel member from deteriorating over time. Further, in this case, the water absorbency of the second lens barrel member is lower than that in the case where the second lens barrel member is made of crystalline resin. Therefore, the second lens barrel member is difficult to absorb moisture existing outside the second lens barrel member, so that moisture is difficult to enter into the inside of the second lens barrel member. Thereby, it is possible to suppress the image side surface of the first lens and each lens constituting the lens group from fogging up. Furthermore, since the second lens barrel member does not easily absorb moisture, the dimensions and shape of the second lens barrel member are stable. This stabilizes the optical performance of the lens group held by the second lens barrel member.

In the present invention, the first lens barrel member includes a first cylinder part including a holding part that holds the first lens from an outer peripheral side, and a first cylinder part that includes a holding part that holds the first lens from the image side to the inner peripheral side of the holding part in the first cylinder part. a protruding annular protrusion; the second lens barrel member includes a second cylindrical part surrounding the lens group from an outer circumferential side; and a flange part that protrudes toward the outer periphery from a middle of the second cylindrical part. The annular protrusion includes a first lens support portion including an annular support surface that supports the first lens from the image side, and a first lens support portion that contacts the second barrel portion from the outside in the radial direction and supports the second lens barrel. a radial positioning part that positions the member in the radial direction; an optical axis positioning part that contacts the flange part from the object side to position the second lens barrel member in the optical axis direction; and an optical axis positioning part that positions the second barrel member in the optical axis direction. a flat portion located on the outside in the radial direction, the flange portion having an annular outer circumferential surface, and the connecting member being an annular member, an inner circumferential surface in contact with the outer circumferential surface, and the planar portion and an annular surface that abuts in the optical axis direction, the first fixing part is provided between the flat part and the annular surface, and the second fixing part is provided between the outer circumferential surface and the inner circumferential surface. It may be provided between the In this way, the second lens barrel member is fixed to the first lens barrel member with high positional accuracy. Therefore, even when the lens barrel is made up of two members, it is possible to suppress a decrease in positional accuracy between the first lens and the lens group.

In the present invention, the second cylindrical portion includes a first portion located closer to the object than the flange, a second portion that overlaps the flange in a direction perpendicular to the optical axis direction, and a second portion located closer to the object than the flange. and a third portion located on the image side, a plurality of protrusions arranged in the circumferential direction are provided on an end surface on the inner peripheral side of the annular protrusion, and the plurality of protrusions are arranged on the inner peripheral side of the annular protrusion, and the plurality of protrusions The radial positioning portion may contact from the outside in the radial direction. In this way, when the second barrel part of the second barrel member is press-fitted inside the annular protrusion of the first barrel member, a gap is formed between the protrusions in the circumferential direction. Therefore, air between the first lens barrel member that holds the first lens and the second lens barrel member that holds the lens group can escape through this gap. This makes it easy to press-fit the second lens barrel member holding the lens group inside the annular protrusion of the first lens barrel member.

In the present invention, one of the flat portion and the annular surface is provided with a first protrusion that protrudes in the optical axis direction and serves as a welding substitute, and the first fixing portion is configured such that the first protrusion is melted by laser welding. Accordingly, it is preferable that the flat portion and the annular surface are welded together. In this way, by melting the first protrusion with a laser, it becomes easy to weld the flat portion and the annular surface.

In the present invention, it is preferable that the second fixing part is formed by laser welding the second lens barrel member and the connecting member. In this way, since no adhesive is used as the second fixing part, there is no possibility that outgas generated from the adhesive will stay inside the lens unit and deteriorate the lens performance of the lens unit. Furthermore, since the second fixing portion is not formed by vibration welding, there is no risk that the lens performance of the lens unit will deteriorate during welding. Further, since the characteristics of the resin materials of the second lens barrel member and the connecting member are different, it is easy to laser weld the second lens barrel member and the connecting member, and the strength when laser welding is increased.

In the present invention, one of the outer circumferential surface and the inner circumferential surface is provided with a second protrusion that protrudes in the radial direction and serves as a welding substitute, and the second fixing part is such that the second protrusion is melted by laser welding. Accordingly, it is preferable that the outer circumferential surface and the inner circumferential surface are welded together. In this way, by melting the second protrusion with a laser, it becomes easy to weld the outer circumferential surface and the inner circumferential surface.

In the present invention, the plurality of lens groups include a second lens located on the image side of the first lens, and a third lens located on the image side of the second lens, and the second lens A plurality of positioning protrusions arranged in the circumferential direction are provided on the inner peripheral surface of the lens, and the third lens is located inside the second portion in the radial direction and extends from the object side toward the image side. The second portion is provided with an opposing portion facing the second portion with a gap in the radial direction, and a contact portion with which the plurality of positioning protrusions come into contact from the outside in the radial direction, in this order, when viewed from a direction perpendicular to the optical axis. In this case, it is preferable that the second protrusion overlaps the opposing portion. In this way, during laser welding, it is possible to suppress stress generated by melting of the second protrusion from being transmitted to the third lens located on the radially inner side of the second portion. Thereby, generation of distortion in the third lens can be suppressed.

In the present invention, the connecting member may include a stepped portion that protrudes radially inward from the inner circumferential surface and includes a support surface facing the object side, and the support surface may contact the flange portion from the image side. preferable. In this way, the connecting member is positioned with respect to the flange portion in the optical axis direction. Furthermore, after the lens unit is assembled, the second lens barrel member is difficult to come off from the first lens barrel member because the support surface is in contact with the flange portion from the image side.

According to the present invention, even when the first lens barrel member and the second lens barrel member are made of resin having light absorbing properties, the connecting member that connects the first lens barrel member and the second lens barrel member Since the first fixing portion is made of a light-transmitting resin, the first fixing portion for fixing the first lens barrel member and the connecting member can be easily formed by laser welding. Therefore, since the first fixing portion is not formed using adhesive or vibration welding, there is no risk that the lens performance of the lens unit will deteriorate.

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. FIG. 3 is an exploded perspective view of the lens unit. FIG. 3 is a perspective view of the first lens barrel member when viewed from the image side. FIG. 7 is a perspective view of the second lens barrel member when viewed from the image side. FIG. 3 is a cross-sectional perspective view of a connecting member. FIG. 7 is an explanatory diagram of a state in which the second lens barrel member is press-fitted into the first lens barrel member. FIG. 7 is an explanatory diagram of a state in which the second lens barrel member is press-fitted into the first lens barrel member when a modified example of the connecting member is used.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of lens units to which the present invention is applied will be described below with reference to the drawings.

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 of the lens unit taken along line AA in FIG. FIG. 3 is an exploded perspective view of the lens unit. 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 FIG. 2, the lens unit 1 includes a lens group 4 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. have 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 X2 to the image side X1. The fifth lens 8 is a cemented lens made by cementing two lenses. Each of the lenses 5 to 8 constituting the lens group 4 has a smaller outer diameter than the first lens 2. In addition, the lens knit includes an annular light shielding sheet 9 disposed between the second lens 5 and the third lens 6, and an annular diaphragm disposed between the third lens 6 and the fourth lens 7. 10.

The first lens 2 is made of resin or glass. The first lens 2 is a meniscus lens. The first lens 2 includes, on the object side X2, a curved surface that projects toward the object side X2. Further, the first lens 2 includes, on the image side X1, a curved surface 2a that is recessed toward the object side X2, and an annular flange surface 2b that extends in a direction perpendicular to the optical axis L on the outer peripheral side of the curved surface 2a. 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 second lens 5 includes an object side lens portion 5a whose outer peripheral surface extends parallel to the optical axis L from one side to the other side in the optical axis direction X, and an object side lens portion 5a whose outer peripheral surface extends toward the image side X1 on the inner peripheral side. and an inclined image-side lens portion 5b in this order.

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 third lens 6 includes an object side lens portion 6a whose outer peripheral surface extends parallel to the optical axis L from one side to the other side in the optical axis direction X, and an object side lens portion 6a whose outer peripheral surface extends toward the image side X1 on the inner peripheral side. and an inclined image-side lens portion 6b in this order.

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 object side lens 13 has an object side lens portion 8a whose outer peripheral surface extends parallel to the optical axis L from one side to the other side in the optical axis direction X, and an inner peripheral surface whose outer peripheral surface extends toward the image side X1. and an image-side lens portion 8b that is inclined toward the side, in this order. 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 larger 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, the outer diameter dimension of the second lens 5, the outer diameter dimension of the third lens 6, the outer diameter dimension of the holder 11 holding the fourth lens 7, and the outer diameter dimension of the fifth lens 8 are, in this order, becomes slightly shorter. Further, as shown in FIG. 3, 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 portion 16 extending straight in the direction is provided.

(lens barrel)
FIG. 4 is a perspective view of the first lens barrel member when viewed from the image side X1. FIG. 5 is a perspective view of the second lens barrel member viewed from the object side X2. As shown in FIGS. 2 and 3, the lens barrel 3 includes a first lens barrel member 21 that holds the first lens 2, a second lens barrel member 22 that holds the lens group 4, and a first lens barrel member 21 that holds the first lens 2. a connecting member 23 that connects the first lens barrel member 21 and the second lens barrel member 22; a first fixing portion 41 that fixes the first lens barrel member 21 and the connecting member 23; and a first fixing portion 41 that fixes the second lens barrel member 22 and the connecting member 23. A second fixing part 42 is provided. As shown in FIG. 2, the second lens barrel member 22 is housed inside the first lens barrel member 21. As shown in FIG.

The first lens barrel member 21 is made of a crystalline resin with light absorbing properties. The second lens barrel member 22 is made of amorphous resin with light absorbing properties. In this example, the first lens barrel member 21 is made of polyamide resin. The second lens barrel member 22 is made of polycarbonate. The connecting member 23 is made of a crystalline resin having light transmittance. In this example, the connecting member 23 is made of polyamide resin.

(First lens barrel member)
As shown in FIG. 2, FIG. 3, and FIG. and an annular protrusion 26 that protrudes radially inward from the radially inner side. As shown in FIGS. 2 and 3, the first cylindrical portion 25 includes a holding portion 27 on the object side X2 of the annular protrusion 26 that holds the first lens 2 from the outer peripheral side. The first cylindrical portion 25 also includes a skirt portion 28 on the image side X1 of the annular protrusion 26 . Further, the first cylindrical portion 25 includes a first contact portion 29 at the end of the object side X2 that is bent toward the inner circumferential side and abuts the first lens 2 from the object side X2.

As shown in FIGS. 2 and 3, the annular protrusion 26 has a first lens support section 31 that includes, on a surface facing the object side X2, an annular support surface 31a that supports the first lens 2 from the image side X1. . Further, the annular protrusion 26 includes an annular groove 32 recessed toward the image side X1 on the outer peripheral side of the support surface 31a. An annular elastic member 33 is inserted into the annular groove 32 . The elastic member 33 is an O-ring.

A plurality of protrusions 36 are provided on the inner circumferential end surface 35 of the annular protrusion 26 facing radially inward. The plurality of protrusions 36 are arranged in the circumferential direction. In this example, the plurality of protrusions 36 are provided on the image side X1 portion of the inner peripheral end surface 35. Therefore, as shown in FIG. 4, the inner peripheral side end surface 35 of the annular projection 26 facing radially inward forms an annular surface portion 35a that does not include a plurality of projections 36 from the object side X2 toward the image side X1. , and an annular uneven surface portion 35b including a plurality of protrusions 36.

The surface of the annular protrusion 26 facing the image side X1 includes a first reference surface 38 perpendicular to the optical axis L and a first welding surface (flat surface) 39 located on the outside of the first reference surface 38 in the radial direction. Be prepared. The first welding surface 39 is parallel to the first reference plane 38 and is offset from the first reference plane 38 toward the image side X1. A first annular surface 40 facing inward in the radial direction is provided between the first reference surface 38 and the first welding surface in the radial direction.

(Second lens barrel member)
As shown in FIGS. 2, 3, and 5, the second lens barrel member 22 includes a second cylindrical portion 50 that surrounds the lens group 4 from the outer circumferential side, and a flange portion 51 that protrudes from the second cylindrical portion 50 toward the outer circumferential side. and. The flange portion 51 protrudes radially outward from a portion of the second cylinder portion 50 on the object side X2. The second cylindrical portion 50 includes a first portion 52a located closer to the object side X2 than the flange portion 51, a second portion 52b that overlaps the flange portion 51 in a direction perpendicular to the optical axis direction and a third portion 52c located on the side X1.

Further, the second lens barrel member 22 has a holding mechanism 53 that holds the lens group 4 from both sides in the optical axis direction X. The holding mechanism 53 includes a second contact part 54 that is bent radially inward from the object side X2 end of the second cylinder part 50 and contacts the second lens 5 from the object side X2, and an image of the second cylinder part 50. An annular support portion 55 that protrudes radially inward from the side X1 portion and supports the lens group 4 is provided. The support portion 55 comes into contact with the flange portion 13a of the object-side lens 13 in the fifth lens 8 from the image side X1, and supports the lens group 4 from the image side X1. The support portion 55 includes an annular plate portion 56 that projects inward in the radial direction at an end portion on the object side X2. The inner peripheral edge of the annular plate portion 56 defines a circular opening 57 . An image pickup device (not shown) is fixed to the image side X1 surface of the annular plate portion 56 so as to close the circular opening 57.

Here, as shown in FIG. 2, the support portion 55 and the annular plate portion 56 are not in contact with the image side lens 14 of the fifth lens 8. That is, the support portion 55 faces the image-side lens 14 with a gap in the radial direction. The annular plate portion 56 faces the image side lens 14 with a gap in the optical axis direction X.

The inner circumferential surface 60 of the second cylindrical portion 50 is slightly inclined inward toward the image side X1. As shown in FIGS. 3 and 5, between the second contact portion 54 and the support portion 55 on the inner circumferential surface 60 of the second cylindrical portion 50, there is a groove extending in the optical axis direction X along the inner circumferential surface 60. A plurality of ribs 61 (positioning projections) are provided. The ribs 61 are arranged in the circumferential direction. As shown in FIG. 2, when the lens group 4 is housed in the second cylindrical portion 50, each rib 61 includes the object side lens portion 5a of the second lens 5, the object side lens portion 6a of the third lens 6, The lens group 4 is positioned in the radial direction by contacting the holder 11 holding the fourth lens 7 and the object side lens portion 8a of the object side lens 13 of the fifth lens 8 from the outside 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 50, 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 50, there is a gap between ribs 61 that are adjacent to each other in the circumferential direction. , a gap extending in the optical axis direction X is formed.

As shown in FIGS. 2 and 3, the flange portion 51 includes an annular outer peripheral surface 51a facing the outer peripheral side and a second reference surface 51b facing the object side X2. A gap is formed in the radial direction between the outer peripheral surface 51a and the first annular surface 40. The second reference plane 51b is perpendicular to the optical axis L.

(Connection member)
FIG. 6 is a cross-sectional perspective view of the connecting member 23. As shown in FIGS. 3 and 6, the connecting member 23 is an annular member. The connecting member 23 includes an annular surface 23 a that contacts the first welding surface (flat portion) 39 in the optical axis direction, and an inner peripheral surface 23 b that contacts the outer peripheral surface 51 a of the flange portion 51 . The annular surface 3a is provided with a first protrusion 23c that protrudes toward the object side X2 and serves as a welding substitute. The first protrusion 23c protrudes in an annular shape along the annular surface 3a. The inner circumferential surface 23b is provided with a second protrusion 23d that protrudes radially inward and serves as a welding substitute. The second protrusion 23d protrudes in an annular shape along the inner circumferential surface 23b.

(First fixed part)
As shown in FIG. 2, the first fixing portion 41 is formed by laser welding the first welding surface 39 and the annular surface 23a. In this example, the first fixing portion 41 is formed by welding the first protrusion 23c to the first welding surface 39 and the annular surface 23a by laser welding.

(Second fixed part)
As shown in FIG. 2, the second fixing part 42 is formed by laser welding the outer peripheral surface 51a and the inner peripheral surface 23b of the flange part 51. In this example, the second fixing portion 42 is formed by welding the outer circumferential surface 51a and the inner circumferential surface 23b by melting the second protrusion 23d by laser welding.

(Assembling the lens unit)
FIG. 7 is an explanatory diagram of a state in which the second lens barrel member 22 is press-fitted into the first lens barrel member 21. As shown in FIG. When assembling the lens unit 1, there are a first unit assembly operation in which the first lens 2 is held in the first lens barrel member 21, and a second unit assembly operation in which the lens group 4 is held in the second lens barrel member 22. , each performed separately and independently. Thereafter, a fixing operation is performed to fix the connecting member 23 to the assembled second unit by laser welding. Thereafter, a connecting operation is performed to connect and fix the second unit, which has been fixed, and the assembled first unit.

In the first unit assembly operation, the elastic member 33 is inserted into the annular groove 32 of the first lens barrel member 21 . Next, the first lens 2 is inserted into the inner peripheral side of the holding part 27 of the first lens barrel member 21 from the object side Bring it into contact. Thereafter, the first contact portion 29 is formed by caulking the end of the first lens barrel member 21 on the object side X2. Thereby, the first lens 2 is held from the optical axis direction X by the first contact portion 29 and the support surface 31a of the first lens support portion 31. When the first lens 2 is held by the first lens barrel member 21, the elastic member 33 is compressed in the optical axis direction X. The elastic member 33 seals between the first lens 2 and the annular protrusion 26 .

In the second unit assembly operation, the lens group 4 is accommodated in the second lens barrel member 22 from the object side X2, and the lens group 4 is supported by the support portion 55. Thereafter, the second contact portion 54 is formed by caulking the end of the second lens barrel member 22 on the object side X2. Thereby, the lens group 4 is held from both sides in the optical axis direction X by the holding mechanism 53. When the lens group 4 is held by the second lens barrel member 22, the second lens 5 is located inside the first portion 22a in the radial direction, and the third lens is located inside the second portion 22b in the radial direction. 6 is located, and a fourth lens 7 and a fifth lens 8 are located radially inside the third portion 22c.

Next, a fixing operation is performed to fix the connecting member 23 to the second unit by laser welding. First, in the fixing operation, the flange portion 51 of the second lens barrel member 22 is inserted into the connecting member 23 . Then, with the outer circumferential surface 51a and the inner circumferential surface 23b in contact with each other, a laser is irradiated from the outside in the radial direction of the connecting member 23, and the outer circumferential surface 51a and the inner circumferential surface 23b are laser welded, thereby providing a second fixation. A portion 42 is formed. During welding, the outer circumferential surface 51a and the inner circumferential surface 23b are welded while the second protrusion 23d provided on the inner circumferential surface 23b of the connecting member 23 is melted by a laser.

Here, as shown in FIG. 7, the object-side lens portion 6a of the third lens 6 has a second portion 22b facing the opposing portion 6c with a gap in the radial direction from the object side X2 toward the image side X1. and a contact portion 6d with which the plurality of ribs 61 come into contact from the outside in the radial direction. When viewed from a direction perpendicular to the optical axis L, the second protrusion 23d overlaps the opposing portion 6c. Therefore, during laser welding, stress generated by melting of the second protrusion 23d can be suppressed from being transmitted to the third lens 6 located on the radially inner side of the second portion 22b. Thereby, generation of distortion in the third lens 6 can be suppressed.

Next, a connecting operation is performed to connect and fix the second unit to the first unit. In the connecting operation, first, the second lens barrel member 22 holding the lens group 4 is inserted inside the skirt portion 28 . Then, the first portion 52a of the second cylinder portion 50 that is closer to the object side X2 than the flange portion 51 is press-fitted into the annular protrusion 26 of the first lens barrel member 21.

Here, as shown in FIG. 7, the plurality of protrusions 36 provided on the inner peripheral end surface 35 facing radially inward in the annular protrusion 26 of the first lens barrel member 21 have the first portion 52a press-fitted therein. At times, the second annular cylinder portion is positioned in the radial direction by coming into contact with the outer circumferential surface of the first object portion 52a from the outside in the radial direction. That is, the plurality of protrusions 36 of the first lens barrel member 21 are radial positioning portions that position the second lens barrel member 22 in the radial direction. Further, in this example, since the plurality of protrusions 36 are provided on the inner circumferential end surface 35 of the annular protrusion 26 facing radially inward, the second mirror is provided inside the annular protrusion 26 of the first lens barrel member 21. When the second cylindrical portion 50 of the cylindrical member 22 is press-fitted, a gap is formed between the protrusions 36 in the circumferential direction. Therefore, when the second lens barrel member 22 is press-fitted into the first lens barrel member 21, the first lens barrel member 21 that holds the first lens 2 and the second lens barrel member 22 that holds the lens group 4 are The air in between can escape to the outside through the gap. Therefore, it becomes easy to press-fit the second cylindrical portion 50 holding the lens group 4 inside the annular protrusion 26 of the first lens barrel member 21 .

Thereafter, in a state where the first welding surface 39 and the annular surface 23a are in contact with each other, a laser is irradiated from the image side X1 of the connecting member 23 to laser weld the first welding surface 39 and the annular surface 23a. A first fixing portion 41 is formed. During welding, the first protrusion 23c provided on the annular surface 23a of the connecting member 23 is melted by a laser while the outer first welding surface 39 and the annular surface 23a are welded, and the first reference surface 38 of the annular protrusion 26 is and the second reference surface 51b of the flange portion 51 are brought into close contact. Thereby, the first reference surface 38 of the annular protrusion 26 becomes an optical axis direction positioning part that positions the second lens barrel member 22 in the optical axis direction X.

(effect)
According to this example, the first lens 2 is held by the first lens barrel member 21, and the lens group 4 located on the image side X1 of the first lens 2 is held by the second lens barrel member 22. Therefore, when manufacturing the lens unit 1, it is possible to hold the first lens 2 to the first lens barrel member 21 and to hold the lens group 4 to the second lens barrel member 22 separately.

Further, the first lens barrel member 21 and the second lens barrel member 22 are made of resin having light absorbing properties. Therefore, it is possible to suppress ghosts and flares from occurring in the lens unit 1 due to the influence of strong light from the outside.

Further, the first lens barrel member 21 and the second lens barrel member 22 are connected via a connecting member 23. At this time, the first lens barrel member 21 and the connecting member 23 are fixed by the first fixing part 41. The second lens barrel member 22 and the connecting member 23 are fixed by a second fixing portion 42 . Here, the connecting member 23 is made of a resin having light transmittance. Therefore, the first fixing part 41 can be easily formed by laser welding the first lens barrel member 21 and the connecting member 23. Therefore, since the first fixing portion 41 is not formed with adhesive, there is no risk that outgas generated from the adhesive will stay inside the lens unit 1 and the lens performance of the lens unit 1 will deteriorate. Furthermore, since the first fixing portion 41 is not formed by vibration welding, there is no risk that the lens performance of the lens unit 1 will deteriorate during welding. Furthermore, since the characteristics of the resin materials of the first lens barrel member 21 and the connecting member 23 are different, it is easy to laser weld the first lens barrel member 21 and the connecting member 23, and the welding strength when laser welding is becomes higher.

Further, in this example, the first lens barrel member 21 is made of a crystalline resin with light absorbing properties, and the second lens barrel member 22 is made of an amorphous resin with light absorbing properties. Here, crystalline resins have excellent weather resistance compared to amorphous resins. Furthermore, amorphous resins have lower water absorption than crystalline resins. Therefore, when the lens unit 1 is installed in a vehicle-mounted imaging device or an imaging device installed outdoors, it is possible to suppress deterioration over time of the first lens barrel member 21, which is easily exposed to external light. Furthermore, since the second lens barrel member 22 is difficult to absorb moisture existing outside the second lens barrel member 22, it is difficult for moisture to enter the inside of the second lens barrel member 22. Thereby, it is possible to suppress the image side surface of the first lens 2 and the lenses 5 to 8 constituting the lens group 4 from fogging up. Furthermore, since the second lens barrel member 22 does not easily absorb moisture, the dimensions and shape of the second lens barrel member 22 are stabilized. This stabilizes the optical performance of the lens group 4 held by the second lens barrel member 22.

In this example, the connecting member 23 is made of the same resin as the first lens barrel member 21. That is, since the connecting member 23 is made of amorphous resin, the welding strength between the connecting member 23 and the first lens barrel member 21 can be increased.

Further, the image side X1 surface of the annular protrusion 26 of the first lens barrel member 21 includes a first reference surface 38 as an optical axis direction positioning portion that contacts the flange portion 51 from the object side X2. Further, the inner circumferential end surface 35 of the annular protrusion 26 of the first lens barrel member 21 facing radially inward includes a plurality of protrusions 36 . The plurality of protrusions 36 are radial positioning portions that position the second lens barrel member 22 in the radial direction. Thereby, the second lens barrel member 22 is fixed to the first lens barrel member 21 with good positional accuracy. Therefore, even if the lens barrel 3 is composed of two members, the first lens barrel member 21 that holds the first lens 2 and the second lens barrel member 22 that holds the lens group 4, the first lens 2 and the lens group 4 It is possible to suppress the positional accuracy from decreasing.

The annular surface 23a is provided with a first protrusion 23c that protrudes in the optical axis direction and serves as a welding substitute. The first fixing portion 41 is formed by welding the first welding surface 39 and the annular surface 23a by melting the first protrusion 23c by laser welding. Therefore, by melting the first protrusion 23c with a laser, it becomes easy to weld the first welding surface 39 and the annular surface 23a.

The second fixing part 42 is formed by laser welding the second lens barrel member 22 and the connecting member 23. Therefore, since no adhesive is used as the second fixing part 42, there is no fear that outgas generated from the adhesive will stay inside the lens unit 1 and the lens performance of the lens unit 1 will deteriorate. Furthermore, since the second fixing portion 42 is not formed by vibration welding, there is no risk that the lens performance of the lens unit 1 will deteriorate during welding. Furthermore, since the characteristics of the resin materials of the second lens barrel member 22 and the connecting member 23 are different, it is easy to laser weld the second lens barrel member 22 and the connecting member 23, and the strength when laser welding is It gets expensive.

The inner circumferential surface 23b is provided with a second protrusion 23d that protrudes in the radial direction and serves as a welding substitute. The second fixing portion 42 is formed by welding the outer peripheral surface 51a and the inner peripheral surface 23b by melting the second protrusion 23d by laser welding. Therefore, by melting the second protrusion 23d with a laser, it becomes easy to weld the outer circumferential surface 51a and the inner circumferential surface 23b.

A plurality of ribs 61 arranged in the circumferential direction are provided on the inner circumferential surface of the second portion 52b of the second cylindrical portion 50. The third lens 6 is located inside the second portion 52b in the radial direction, and includes an opposing portion 6c in which the second portion 52b faces in the radial direction from the object side X2 toward the image side X1 with a gap therebetween. A contact portion 6d with which the plurality of ribs 61 contacts from the outside in the radial direction is provided in this order. When viewed from a direction perpendicular to the optical axis L, the second protrusion 23d overlaps the opposing portion 6c. Therefore, during laser welding, it is possible to suppress stress due to sink marks, distortion, etc. caused by melting of the second protrusion 23d from being transmitted to the third lens 6 located on the radially inner side of the second portion 22b. can. Thereby, generation of distortion in the third lens 6 can be suppressed.

(Modified example)
The connecting member 23 may include a stepped portion 230 that protrudes radially inward from the inner circumferential surface 23b and includes a support surface 231 facing the object side. FIG. 8 is an explanatory diagram of a state in which the second lens barrel member 22 is press-fitted into the first lens barrel member 21 when the connecting member 23 of the modification is used. As shown in FIG. 8, the connecting member 23 includes a step portion 230 that protrudes radially inward from the inner circumferential surface 23b and includes a support surface 231 facing the object side X2. The flange portion 51 includes a step portion 51c cut out from the outer peripheral edge on the image side X1 toward the object side. When the flange portion 51 of the second barrel member 22 is inserted into the connecting member 23, the stepped portion 230 of the connecting member 23 fits into the stepped portion 51c of the flange portion 51. At this time, the support surface 231 contacts the contact surface 51d of the stepped portion 51c of the flange portion 51 from the image side. Thereby, the connecting member 23 is positioned in the optical axis direction X with respect to the flange portion 51.

Further, after the lens unit 1 is assembled, the support surface 231 is in contact with the contact surface 51d of the stepped portion 51c of the flange portion 51 from the image side, so that the second lens barrel member 22 is in contact with the first lens barrel member. It's hard to get out of 21.

In the above embodiment, the second fixing part 42 was formed by laser welding the second lens barrel member 22 and the connecting member 23, but it may also be formed by adhesive. Here, when an adhesive is used, outgas is generated when the adhesive hardens. However, as explained in the above embodiment, since the first unit and the second unit are assembled separately, even if the second fixing part 42 is formed with adhesive, the The outgas does not stay inside the second lens barrel member 22, but diverges to the outside. When the adhesive is cured, outgas generation has finished. Therefore, even if the second lens barrel member 22 to which the connecting member 23 is fixed is inserted into the first lens barrel member 21 and the first unit and the second unit are connected and fixed, the second lens barrel member 22 Since no outgas is generated from the fixed portion 42, there is no fear that the outgas will stay inside the lens unit 1 and the lens performance of the lens unit 1 will deteriorate.

Note that the present technology can have the following configuration.

(1)
a first lens barrel member that holds a first lens;
a second lens barrel member that holds a lens group located on the inner peripheral side of the first lens barrel member and on the image side of the first lens;
a connecting member that connects the first lens barrel member and the second lens barrel member;
a first fixing part that fixes the first lens barrel member and the connection member;
a second fixing part that fixes the second lens barrel member and the connection member;
has
The first lens barrel member and the second lens barrel member are made of a resin having light absorbing properties,
The connecting member is made of a resin having light transmittance,
The lens unit is characterized in that the first fixing portion is formed by laser welding the first lens barrel member and the connecting member.

(2)
The lens unit according to (1), wherein the connecting member is made of the same resin as one of the first lens barrel member and the second lens barrel member.

(3)
The lens unit according to (1) or (2), wherein the connecting member is made of the same resin as the first lens barrel member.

(4)
The first lens barrel member is made of the crystalline resin having the light absorbing property,
The lens unit according to any one of (1) to (3), wherein the second lens barrel member is made of the amorphous resin having the light-absorbing property.

(5)
The first lens barrel member includes a first cylindrical portion including a holding portion that holds the first lens from an outer circumferential side, and an annular protrusion that protrudes from the image side of the holding portion in the first cylindrical portion toward the inner circumferential side. and,
The second lens barrel member includes a second cylindrical portion that surrounds the lens group from the outer circumferential side, and a flange portion that protrudes toward the outer circumferential side from a middle of the second cylindrical portion,
The annular protrusion includes a first lens support portion having an annular support surface that supports the first lens from the image side, and a first lens support portion that contacts the second barrel portion from the outside in the radial direction to support the second lens barrel member. a radial positioning part for positioning in the radial direction; an optical axis positioning part for positioning the second lens barrel member in the optical axis direction by contacting the flange part from the object side; and a radial direction positioning part for the optical axis direction positioning part. A flat part located on the outside,
The flange portion has an annular outer peripheral surface,
The connecting member is an annular member, and includes an inner peripheral surface that contacts the outer peripheral surface, and an annular surface that contacts the flat part in the optical axis direction,
The first fixing part is provided between the flat part and the annular surface,
The lens unit according to any one of (1) to (4), wherein the second fixing portion is provided between the outer peripheral surface and the inner peripheral surface.

(6)
The second cylindrical portion includes a first portion located closer to the object than the flange, a second portion overlapping the flange in a direction perpendicular to the optical axis direction, and a second portion located closer to the image than the flange. and a third portion located at
A plurality of protrusions arranged in the circumferential direction are provided on the inner peripheral side end surface of the annular protrusion,
The lens unit according to (5), wherein the plurality of projections are the radial positioning portions that contact the first portion from the outside in the radial direction.

(7)
A first protrusion for welding that protrudes in the optical axis direction is provided on one of the flat part and the annular surface,
The lens according to (5) or (6), wherein the first fixing part is formed by welding the flat part and the annular surface by melting the first protrusion by laser welding. unit.

(8)
The lens unit according to (6), wherein the second fixing portion is formed by laser welding the second lens barrel member and the connecting member.

(9)
A second protrusion protruding in the radial direction and serving as a welding substitute is provided on one of the outer circumferential surface and the inner circumferential surface,
The lens unit according to (8), wherein the second fixing portion is formed by welding the outer circumferential surface and the inner circumferential surface by melting the second projection by laser welding.

(10)
The plurality of lens groups include a second lens located on the image side of the first lens, and a third lens located on the image side of the second lens,
A plurality of positioning protrusions arranged in the circumferential direction are provided on the inner circumferential surface of the second portion,
The third lens is located inside the second portion in the radial direction, and includes a plurality of opposing portions in which the second portion faces in the radial direction from the object side toward the image side with a gap therebetween. a contact portion with which the positioning protrusion contacts from the outside in the radial direction, in this order;
The lens unit according to (9), wherein the second protrusion overlaps the opposing portion when viewed from a direction perpendicular to the optical axis.

(11)
The connecting member includes a step portion that protrudes radially inward from the inner circumferential surface and includes a support surface facing the object side,
(5) to (10), wherein the support surface abuts the flange portion from the image side.
) The lens unit described in any of the above.

DESCRIPTION OF SYMBOLS 1... Lens unit, 2... First lens, 2a... Curved surface, 2b... Flange surface, 3... Lens barrel, 4... Lens group, 5... Second lens, 5a... Object side lens part, 5b... Image side lens part , 6... Third lens, 6a... Object side lens part, 6b... Image side lens part, 7... Fourth lens, 8... Fifth lens, 8a... Object side lens part, 8b... Image side lens part, 9... Light shielding Sheet, 10... Aperture, 11... Holder, 13... Object side lens, 13a... Flange portion, 14... Image side lens, 16... Notch, 21... First lens barrel member, 22... Second lens barrel member, 23 ... Connecting member, 23a... Annular surface, 23b... Inner peripheral surface, 23c... First protrusion, 23d... Second protrusion, 25... First cylindrical portion, 26... Annular protrusion, 27... Holding portion, 28... Skirt portion, 29... First contact part, 31... First lens support part, 31a... Support surface, 32... Annular groove, 33... Elastic member, 35... Inner peripheral side end surface, 35a... Annular surface part, 35b... Uneven surface part, 36...Protrusion, 38...First reference surface, 39...First welding surface, 41...First fixing part, 42...Second fixing part, 50...Second cylinder part, 51...Flange part, 51a...Outer peripheral surface, 51b ...Second reference surface, 51c...Step part, 51d...Abutting surface, 52a...First part, 52b...Second part, 52c...Third part, 53...Holding mechanism, 54...Second abutting part, 55... Support part, 56... Annular plate part, 57... Circular opening, 60... Inner peripheral surface, 61... Rib, 64... Second welding surface, 230 Step part, 231... Support surface, L... Optical axis

Claims (11)

a first lens barrel member that holds a first lens;
a second lens barrel member that holds a lens group located on the inner peripheral side of the first lens barrel member and on the image side of the first lens;
a connecting member that connects the first lens barrel member and the second lens barrel member;
a first fixing part that fixes the first lens barrel member and the connection member;
a second fixing part that fixes the second lens barrel member and the connection member;
has
The first lens barrel member and the second lens barrel member are made of a resin having light absorbing properties,
The connecting member is made of a resin having light transmittance,
The lens unit is characterized in that the first fixing portion is formed by laser welding the first lens barrel member and the connecting member. The lens unit according to claim 1, wherein the connecting member is made of the same resin as one of the first lens barrel member and the second lens barrel member. 3. The lens unit according to claim 2, wherein the connecting member is made of the same resin as the first lens barrel member. The first lens barrel member is made of the crystalline resin having the light absorbing property,
3. The lens unit according to claim 2, wherein the second lens barrel member is made of an amorphous resin having the light absorbing property. The first lens barrel member includes a first cylindrical portion including a holding portion that holds the first lens from an outer circumferential side, and an annular protrusion that protrudes from the image side of the holding portion in the first cylindrical portion toward the inner circumferential side. and,
The second lens barrel member includes a second cylindrical portion that surrounds the lens group from the outer circumferential side, and a flange portion that protrudes toward the outer circumferential side from a middle of the second cylindrical portion,
The annular protrusion includes a first lens support portion having an annular support surface that supports the first lens from the image side, and a first lens support portion that contacts the second barrel portion from the outside in the radial direction to support the second lens barrel member. a radial positioning part for positioning in the radial direction; an optical axis positioning part for positioning the second lens barrel member in the optical axis direction by contacting the flange part from the object side; and a radial direction positioning part for the optical axis direction positioning part. A flat part located on the outside,
The flange portion has an annular outer peripheral surface,
The connecting member is an annular member, and includes an inner peripheral surface that contacts the outer peripheral surface, and an annular surface that contacts the flat part in the optical axis direction,
The first fixing part is provided between the flat part and the annular surface,
5. The lens unit according to claim 1, wherein the second fixing part is provided between the outer circumferential surface and the inner circumferential surface. The second cylindrical portion includes a first portion located closer to the object than the flange, a second portion overlapping the flange in a direction perpendicular to the optical axis direction, and a second portion located closer to the image than the flange. and a third portion located at
A plurality of protrusions arranged in the circumferential direction are provided on the inner peripheral side end surface of the annular protrusion,
6. The lens unit according to claim 5, wherein the plurality of projections are the radial positioning portions that contact the first portion from the outside in the radial direction. A first protrusion for welding that protrudes in the optical axis direction is provided on one of the flat part and the annular surface,
7. The lens unit according to claim 6, wherein the first fixing part is formed by welding the flat part and the annular surface by melting the first protrusion by laser welding. 8. The lens unit according to claim 7, wherein the second fixing part is formed by laser welding the second lens barrel member and the connecting member. A second protrusion protruding in the radial direction and serving as a welding substitute is provided on one of the outer circumferential surface and the inner circumferential surface,
9. The lens unit according to claim 8, wherein the second fixing part is formed by welding the outer circumferential surface and the inner circumferential surface by melting the second projection by laser welding. The plurality of lens groups include a second lens located on the image side of the first lens, and a third lens located on the image side of the second lens,
A plurality of positioning protrusions arranged in the circumferential direction are provided on the inner circumferential surface of the second portion,
The third lens is located inside the second portion in the radial direction, and includes a plurality of opposing portions in which the second portion faces in the radial direction from the object side toward the image side with a gap therebetween. a contact portion with which the positioning protrusion contacts from the outside in the radial direction, in this order;
The lens unit according to claim 9, wherein the second protrusion overlaps the opposing portion when viewed from a direction perpendicular to the optical axis. The connecting member includes a step portion that protrudes radially inward from the inner circumferential surface and includes a support surface facing the object side,
The lens unit according to claim 5, wherein the support surface contacts the flange portion from the image side.

Images