JP2019204000A - Lens unit and camera module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens unit in which peeling of a filter due to deformation of a weld portion in a lens barrel is suppressed. A lens unit (100) includes a lens barrel (10) including a weld portion (50) formed at a position where molten resin merges, lenses (1) to (4) arranged on the inner peripheral side of the lens barrel, and a lens barrel (10). A filter 20 adhered to one end in the axial direction is provided, and a concave portion 51 is formed on the surface of the lens barrel 10 to which the filter 20 is adhered so as to include at least a part of the weld portion 50. 20 is bonded via the adhesive applied to the recess 51. [Selection diagram] Figure 2

Description

  The present invention relates to a lens unit and a camera module.

  A technique is known in which a camera (on-vehicle camera) mounted on a vehicle captures an image of a scenery outside the vehicle and the captured image is displayed on a monitor or the like mounted on the interior of the vehicle. The lens unit of the in-vehicle camera is required to have strength, waterproofness, chemical resistance, high temperature durability, and the like because the side (object side) directed to the imaging target is exposed outside the vehicle. In addition, it is necessary to prevent the lens from fogging due to temperature changes.

  Patent Document 1 discloses a lens unit that ensures an airtight state inside a lens barrel in order to prevent the lens from being fogged. In this lens unit, four lenses are arranged in the lens barrel along the optical axis direction. On the object side, sealing performance is realized by arranging a 0 ring between the lens closest to the object side and the inner peripheral surface of the lens barrel. On the image side (image sensor side), the sealing property is realized by attaching an optical filter to the lens barrel via an adhesive. As described above, the object-side seal and the imaging-side seal ensure airtightness inside the lens barrel and prevent the lens from fogging.

Japanese Patent No. 4999508

Incidentally, some lens units as described above have a lens barrel formed of resin. FIG. 7 is a sectional view in the axial direction of a lens unit 500 including a resin lens barrel 510. In FIG. 7, hatching indicating a cross-sectional view is omitted.
Inside the lens barrel 510, lenses 501 to 504, intermediate rings 521, 522 and the like are arranged. The lenses 501 to 504 are circular glass lenses, and are inserted on the inner peripheral side of the lens barrel 510. The lenses 501 to 504 are arranged in a state of being aligned along the optical axis so that the respective optical axes coincide with each other. The intermediate rings 521 and 522 are resin-made annular parts disposed between the lenses. Hereinafter, the lens 504 side in the lens barrel 510 is referred to as an image side, and the lens 501 side is referred to as an object side.

The lens barrel 510 includes a support portion 511 that is a portion protruding toward the inside in the radial direction so that the inner diameter becomes smaller at the image side portion on the inner peripheral surface. The support portion 511 comes into contact with the image side surface of the flange portion of the lens 504. The flange portion of the lens is a portion having a flat surface formed on the outer peripheral side of the lens effective diameter.
In addition, the lens barrel 510 includes a holding portion 512 that is formed at an end portion on the object side and abuts on the outer peripheral portion of the object-side surface of the lens 501. The holding part 512 is a part formed by caulking after the parts are accommodated in the lens barrel 510. The lenses 501 to 504 housed in the lens barrel 510 and the intermediate rings 521 and 522 are supported so as to be sandwiched between the holding portion 512 and the support portion 511. As a result, no gap is formed between the components.

  Further, the lens barrel 510 includes a flange portion 513 that is a plate-like portion protruding outward in the radial direction on the outer peripheral surface thereof. The lens barrel 510 is provided with a counterbore portion 514 having a circular shape coaxial with the lens barrel 510 and recessed toward the object side at the end on the image side. A circular filter 530 is attached to the counterbore part 514 with an adhesive. Adhesion is realized by, for example, dropping an adhesive on the counterbore part 514 and placing the filter 530 thereon. The filter 530 is pasted to remove a specific frequency component of external light.

Here, the weld part of the resin lens barrel 510 will be described with reference to FIG.
As shown in FIG. 8A, the weld portion (weld line) is formed by fusing the resins at the position where the flows of the molten resin flowing inside the mold merge when the lens barrel 510 is molded. It is a part. FIG. 8B is a P view of FIG. As shown in FIG. 8B, the gates of the mold for forming the lens barrel 510 are provided at three positions at equal intervals along the circumferential direction, for example, at positions radially outside the flange portion 513. Yes. In this case, the weld part is formed at three positions at substantially equal intervals along the circumferential direction.

  The weld portion where the resin is fused has a large amount of expansion / contraction deformation at high temperatures. Therefore, when the lens barrel 510 with the filter 530 attached is left in a high temperature environment, a high temperature and high humidity environment, an environment where a thermal shock is applied, or the like for a long time, the filter 530 peels off due to deformation of the weld portion. There was a problem that it would end up. The peeling includes not only the case where the filter 530 is completely peeled off from the lens barrel 510 but also the case where the position of the filter 530 facing the weld is changed to white. When the filter 530 is peeled off, the optical performance of the lens unit 500 is deteriorated.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a lens unit and a camera module in which separation of a filter due to deformation of a weld portion of a lens barrel is suppressed.

In order to solve the above problems, the lens unit of the present invention is:
A lens barrel provided with a weld portion formed at a position where the molten resin merges, and a lens disposed on the inner peripheral side of the lens barrel,
A filter bonded to one end in the axial direction of the lens barrel;
A concave portion is formed on the surface of the lens barrel to which the filter is bonded so as to include at least a part of the weld portion, and the filter is bonded via an adhesive applied to the concave portion. It is characterized by.

  According to such a configuration, even when the weld portion is deformed in a high temperature environment or the like, the adhesive applied to the concave portion is elastically deformed in accordance with the deformation, and plays a role of absorbing the deformation. Thereby, peeling of a filter can be suppressed.

  Moreover, the said structure WHEREIN: You may make it the said filter adhere | attach via the adhesive agent apply | coated to the said recessed part, and the adhesive agent apply | coated to the surface facing the said filter in the said lens-barrel.

  According to such a configuration, it is possible to suppress the peeling of the filter and to further strengthen the adhesion between the lens barrel and the filter.

  The camera module of the present invention includes the lens unit having the above-described configuration and an image sensor that captures an image formed by the lens unit.

  According to such a configuration, the camera module can achieve the same effects as the above-described lens unit of the present invention.

  According to the present invention, it is possible to provide a lens unit and a camera module in which peeling of a filter due to deformation of a weld portion in a lens barrel is suppressed.

It is an axial sectional view showing the lens unit concerning the embodiment of the present invention. It is a figure for demonstrating adhesion | attachment of a lens-barrel and a filter, (a) is the schematic which looked at the lens-barrel from the axial direction image side. (B) is a figure which shows the case where the recessed part is not provided. (C) is a figure which shows the case where a recessed part is provided. It is a figure for demonstrating the width | variety of a recessed part similarly. It is a figure which shows the modification of a recessed part similarly. It is a figure which shows the case where the weld part is formed in another position similarly. It is a figure which shows another example of adhesion | attachment of a filter similarly. It is an axial sectional view for explaining a conventional problem. It is a figure for demonstrating the conventional subject, (a) is the schematic which looked at the lens-barrel from the side. (B) is the schematic which looked at the lens-barrel from the axial direction image side.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an axial sectional view of a lens unit 100 according to the present embodiment. In FIG. 1, hatching indicating a cross section is omitted. The lens unit 100 is used for an in-vehicle camera, for example.

  As shown in FIG. 1, the lens unit 100 includes lenses 1, 2, 3, 4, a lens barrel 10, a filter 20, intermediate rings 31, 32, an O-ring 40, and the like.

  In the lens barrel 10, lenses 1 to 4 constituting one lens group are arranged side by side along the axial direction of the lens barrel 10. The lenses 1 to 4 are arranged in a state in which the respective optical axes are aligned and arranged along the optical axis. At this time, the axis of the lens barrel 10 and the optical axis of the lens group (referred to as the optical axis OA) are substantially coincident with each other. Hereinafter, the optical axis OA indicates the optical axis of each lens 1 to 4 and the optical axis of the lens group.

  The lens barrel 10 is arranged so that one end in the axial direction faces the image sensor (not shown) as the image side, and the other end in the axial direction faces the imaging target as the object side. Has been placed. In the present embodiment, the lens 4 side is the image side, and the lens 1 side is the object side. Note that the imaging element is disposed in a camera case (not shown) to which the lens unit 100 is attached in order to capture an image formed by the lens unit 100.

  The lenses 1 to 4 are arranged inside the lens barrel 10 in the order of the lens 1, the lens 2, the lens 3, and the lens 4 from the object side to the image side. The filter 20 is disposed at the end of the lens 1 to 4 on the side (image side) that connects the images. The filter 20 is arranged for the purpose of removing a specific frequency component of external light. The filter 20 is formed by evaporating a multilayer film on glass, for example. In the present embodiment, the filter 20 is a circular infrared cut filter (IRCF).

  The cylindrical barrel 10 is made of resin. The inner diameter of the lens barrel 10 gradually decreases from the object side to the image side. A support portion 11 that is a portion projecting inward in the radial direction so as to reduce the inner diameter is formed on the image side portion of the inner circumferential surface located closest to the image side of the lens barrel 10. The support portion 11 comes into contact with the image side surface of the flange portion of the lens 4. A flange part is a site | part provided with the flat surface formed in the outer peripheral side of a lens effective diameter.

  The lens barrel 10 includes a holding portion 12 that is formed at an end portion on the object side and abuts on the outer peripheral portion of the object-side surface of the lens 1. The holding part 12 is a part formed by caulking after the parts are accommodated in the lens barrel 10. The inner diameter of the holding part 12 is smaller than the outer diameter of the lens 1. The components housed inside the lens barrel 10 are supported so as to be sandwiched between the support portion 11 and the holding portion 12. In other words, the components housed inside the lens barrel 10 are held in a state of being pressed toward the support portion 11 by the holding portion 12. As a result, no gap is formed between the components.

  The lenses 1 to 4 are circular lenses that are inserted into the lens barrel 10. The lenses 1 to 4 are made of resin or glass. The lenses 1 to 4 are positioned with respect to the direction orthogonal to the optical axis OA by the outer peripheral surface thereof being in contact with the inner peripheral surface of the lens barrel 10.

  The intermediate rings 31 and 32 are metal or resin annular parts, and are inserted between the lenses.

  A reduced diameter portion 1 a formed with a smaller diameter than the other portion is formed on the image side portion of the outer peripheral surface of the lens 1. An O-ring 40 is disposed between the reduced diameter portion 1 a and the inner peripheral surface A of the lens barrel 10. The O-ring 40 is made of rubber, seals the gap, and prevents water, dust, etc. from entering the inside of the lens barrel 10.

  The lens unit 100 constitutes a camera module together with an image sensor, a wiring board, a signal processing circuit, a flexible wiring sheet, a connector, and the like. The camera module refers to a camera module including at least the lens unit 100 and an image sensor. The imaging element is arranged on the image side of the lens unit 100 and captures an image formed by the lens unit 100.

  The camera module operates as follows. Light incident from the object side enters the image sensor via the lens group of the lens unit 100. The image sensor converts an incident image into an electric signal. The signal processing circuit performs signal processing (A / D conversion, image correction processing, etc.) on the electric signal from the image sensor. An electrical signal output from the signal processing circuit is connected to an external electronic device via a flexible wiring sheet and a connector.

  At the end of the lens barrel 10 on the image side, a counterbore portion 14 is formed which has a circular shape coaxial with the lens barrel 10 and is recessed toward the object side. A filter 20 is attached to the counterbore part 14 with an adhesive.

  There are organic and inorganic adhesives. In the present embodiment, an organic adhesive is preferable. Organic adhesives include synthetic and natural adhesives, and synthetic adhesives are preferred. For example, an ultraviolet curable resin, a thermosetting resin, a thermoplastic resin, or the like.

  In the above, the case where the counterbore part 14 is provided at the image side end of the lens barrel 10 has been described, but the counterbore part 14 is not necessarily provided, and the image side plane of the lens barrel 10 is The filter 20 may be pasted.

FIG. 2 is a view for explaining adhesion between the lens barrel 10 and the filter 20.
FIG. 2A is a schematic view of the lens barrel 10 viewed from the axial image side.
A concave portion 51 is formed on the image side surface of the lens barrel 10 so as to include at least a part of the weld portion 50. The recess 51 is formed so as to include a position facing the filter 20. The recess 51 is, for example, a groove having a U-shaped cross section. The recess 51 is coated (filled) with an adhesive, and the filter 20 is affixed to the lens barrel 10 via the adhesive applied to the recess 51.

  FIG. 2B is a view for explaining adhesion of the filter 20 when the recess 51 is not provided. The welded portion 50 of the lens barrel 10 undergoes expansion and contraction deformation when shifting from a normal temperature to a high temperature environment or when left in a high temperature environment for a long time. When the recess 51 is not provided, since the adhesive layer of the adhesive interposed between the lens barrel 10 and the filter 20 is thin, the adhesive layer becomes brittle due to the influence of the deformation of the weld 50, and the filter 20 will peel off.

  FIG. 2C is a diagram for explaining adhesion of the filter 20 when the recess 51 is provided. Since the concave portion 51 is filled with the adhesive, the thickness of the adhesive layer of the adhesive interposed between the lens barrel 10 and the filter 20 is increased. For this reason, the adhesive layer is deformed with the deformation of the weld portion 50, and the adhesive layer plays a role of absorbing the deformation of the weld portion 50. In other words, the adhesive layer moves elastically in accordance with the movement of the weld portion 50. Thereby, peeling of the filter 20 due to the deformation of the weld 50 is suppressed, and a decrease in optical performance of the lens unit 100 can be prevented.

  The depth of the recess 51 is 5 μm to 1000 μm. As for the depth of the recessed part 51, it is more preferable that 10 micrometers is ensured. This is because the adhesive layer is thickened and the effect of suppressing separation of the filter 20 is made more effective. The depth of the recess 51 is more preferably up to 200 μm. This is to ensure the strength of the lens barrel 10.

Further, the recess 51 needs to be formed with a predetermined width so that the weld 50 is accurately formed inside the recess 51. The recess 51 is preferably formed with a predetermined width in the innermost peripheral portion of the flat portion of the lens barrel 10 on which the filter 20 is placed in consideration of fluctuation due to molding conditions and the like. FIG. 3 is a diagram for explaining the width of the recess 51. FIG. 3 shows an example in which the width of the recess 51 is formed so as to have an angle of 5 °. The width of the recess 51 is preferably formed so that the angle is 2 ° or more and 30 ° or less. The width of the recess 51 is more preferably formed so that the angle is 2 ° or more and 10 ° or less. In this embodiment, the width of the recess 51 is an angle of 5 °. In FIG. 2A, the recess 51 is rectangular, but the recess 51 is preferably trapezoidal so that the width gradually increases toward the outer periphery.
The width of the recess 51 is desirably 0.1 to 5 mm. The width of the recess 51 is more preferably 1 mm or less. This is to suppress an increase in cost due to a decrease in strength of the lens barrel and an increase in the amount of adhesive applied.

  Moreover, the length of the recessed part 51 with respect to a radial direction is 0.1-10 mm. The length of the recess 51 is more preferably 5 mm or less. This is for suppressing an increase in cost due to an increase in the amount of adhesive applied.

  Here, as shown in FIG. 2A, let R be the radial length of the portion facing the filter 20 in the planar portion of the lens barrel 10. The ratio of the length of the recess 51 in the length R is 5 to 100%. As for the said ratio, it is more preferable that 10% is ensured. This is for securing the adhesive layer and making the effect of suppressing the peeling of the filter 20 more effective. Further, the ratio is more preferably 50% or less. This is for suppressing an increase in cost due to an increase in the amount of adhesive applied.

  FIG. 4 is a diagram for explaining a modification of the recess 51. The recessed part 51 can be comprised like the recessed part 51A-the recessed part 51E shown in FIG. It is good also as a combination of several hollows, such as elliptical shape, rectangular shape, or trapezoid shape like the recessed part 51A-the recessed part 51C. Moreover, it is good also as a combination of a some groove | channel like recessed part 51D. Moreover, it is good also as a combination of a hollow and a groove | channel like the recessed part 51E. In addition, the cross-sectional shape of the recess or groove may be a V-shaped cross section, a polygonal cross section, a semicircular cross section, or the like. In addition, the recessed part 51 does not need to be made into the same shape in all the 3 recessed parts 51 in Fig.2 (a), and can be made into the combination of arbitrary shapes.

  FIG. 5 is a diagram illustrating a case where the weld 50 is formed at another position in the lens barrel 10. When the molten resin is caused to flow from the two gate positions shown in FIG. 5, the weld portion 50 is formed at two locations where the molten resin joins. In this case, the recess 51 is formed in each of the two welds 50. Thus, the recessed part 51 should just be formed according to the number of the weld parts 50 formed in the lens-barrel 10. However, the recess 51 may be additionally formed at a location where the weld 50 is not generated.

  In the above description, the case where the filter 20 is bonded to the lens barrel 10 through the adhesive applied to the concave portion 51 has been described. However, in addition to the concave portion 51, the surface facing the filter 20 (adhesion surface) in the lens barrel 10. ) May also be applied so that the filter 20 is adhered. In other words, the filter 20 may be bonded via the adhesive applied to the recess 51 and the adhesive applied to the surface where the weld 50 is not formed. The latter adhesive may be surface coating or point coating. By comprising in this way, peeling of the filter 20 resulting from a deformation | transformation of the weld part 50 is suppressed, and adhesion | attachment of the filter 20 becomes stronger.

  In the above description, the filter 20 is pasted after the adhesive is applied to the lens barrel 10. However, the filter 20 is placed in advance on the image-side surface of the lens barrel 10, and becomes the radially outer side of the filter 20. The filter 20 may be affixed by pouring an adhesive between the filter 20 and the lens barrel 10 through an adhesive application groove (not shown) provided at the position.

FIG. 6 is a diagram for explaining a modification in which the filter 20 is bonded by another method.
In this modification, the weld 51 is not provided with the recess 51. In this modification, an adhesive is applied to a portion other than the weld portion 50, and the filter 20 is attached to the image side surface of the lens barrel 10 via the adhesive. In other words, the filter 20 is adhered to the image side surface of the lens barrel 10 via an adhesive applied to a portion other than the weld portion 50. The application of the adhesive is, for example, point application. Although FIG. 6 shows a case where an adhesive is applied to three places other than the weld portion 50, the number of adhesives applied is not limited to this. The adhesive may be applied to n places (n is an integer of 1 or more) so as to avoid the weld 50. With this configuration, even if the weld 50 is deformed in a high-temperature environment or the like, peeling of the filter 20 due to the deformation is suppressed. Thereby, the fall of the optical performance of the lens unit 100 can be prevented.

1, 2, 3, 4 Lens 10 Lens barrel 20 Filter 50 Weld part

Claims (3)

A lens barrel provided with a weld portion formed at a position where the molten resin merges, and a lens disposed on the inner peripheral side of the lens barrel,
A filter bonded to one end in the axial direction of the lens barrel;
A concave portion is formed on the surface of the lens barrel to which the filter is bonded so as to include at least a part of the weld portion, and the filter is bonded via an adhesive applied to the concave portion. Lens unit characterized by   The lens according to claim 1, wherein the filter is bonded via an adhesive applied to the concave portion and an adhesive applied to a surface of the lens barrel facing the filter. unit.   A camera module comprising: the lens unit according to claim 1; and an image pickup device that picks up an image formed by the lens unit.

Images