JP7364344B2 - Lens unit and camera module - Google Patents

Description

The present invention relates to a lens unit and a camera module that can constitute an on-vehicle camera mounted on a vehicle such as an automobile.

Vehicles have traditionally been equipped with in-vehicle cameras to support parking and use image recognition to prevent collisions, and attempts are also being made to apply this to autonomous driving. In addition, a camera module such as such a vehicle-mounted camera generally includes a lens group consisting of a plurality of lenses arranged along the optical axis, a lens barrel that accommodates and holds this lens group, and at least one of the lens groups. The lens unit includes a diaphragm member disposed between lenses at one location (see, for example, Patent Document 1).

In addition, particularly in a lens unit for an in-vehicle camera, when at least a part of the lens unit is installed outside the vehicle, a lens group L is installed in the inner housing space S of the lens barrel 102 for waterproof and dustproof purposes, as shown in FIG. In the assembled and housed state, an O-ring 104 is inserted between the first lens 100 located closest to the object side of the lens group L and the lens barrel 102, and the O-ring 104 is inserted between the lens barrel 102 and the lens group inside the lens barrel 102. This prevents water and dust from entering inside L. In this case, a step-shaped reduced diameter portion 100b whose diameter becomes smaller at the image side portion of the lens 100 is provided on the outer peripheral side surface 100a of the first lens 100, and an O-ring 104 is attached to this reduced diameter portion 100b. Then, the O-ring 104 is compressed in the radial direction between the outer circumferential side surface 100a of the first lens 100 and the inner circumferential surface 102a of the lens barrel 102, so that the object side end of the lens barrel 102 is sealed. It is in a state.

Further, in the lens barrel 102, when the lens group L is installed and housed in the inner housing space S, the caulking portion 123 at the object side end (the upper end in FIG. 4) is radially inward. By being crimped, the first lens 100 is fixed to the object side end of the lens barrel 102 by the crimped portion 123.

JP2013-231993A

By the way, even if waterproof measures are taken using the O-ring 104 as described above, moisture (water vapor) can enter the lens unit through various routes. Therefore, when the difference between the outside temperature and the temperature inside the lens unit becomes large, water vapor inside the lens unit condenses and dew condensation occurs on the lens surface. In particular, dew condensation occurs on the back surface 100c of the first lens 100 in the inter-lens space S1 between the first lens 100 and the second lens 101 adjacent thereto, which is most affected by the temperature difference with the outside. Easy to occur.

The reason why the difference between the outside temperature and the temperature inside the lens unit increases is that the temperature inside the lens unit increases during the winter when the outside air is cold. The temperature inside the lens unit may rise due to heat transmitted from the image sensor (imaging device), which is constantly energized to convert the image into a For example, the first lens 100 may be cooled when the surface 100d of the first lens 100 is exposed to rain or splashed with water from a puddle on the road surface while the temperature of the first lens 100 is high.

In addition, the paths that allow water vapor to enter into the lens unit include, for example, a gap between the caulked portion 123 of the lens barrel 102 and the first lens 100, a part of the periphery of the O-ring 104, and the first Examples include a path leading to the inter-lens space S1 etc. through a gap between the lens 100 and the lens barrel 102 and/or the second lens 101, or a moisture permeable resin forming the lens barrel 102 and the lens. .

In any case, if water vapor enters the lens unit through such a path and a temperature difference occurs between the outside air and the lens unit due to the factors mentioned above, condensation will occur and the captured image will become blurred. The desired resolution cannot be obtained. Therefore, it is required to further ensure the airtightness of the lens unit and to suppress the intrusion of water vapor into the lens unit.

The present invention has been made in view of the above-mentioned circumstances, and it is an object of the present invention to provide a lens unit and a camera module that can suppress the intrusion of water vapor into the lens unit and prevent dew condensation on the lens surface.

In order to solve the above problems, the present invention provides a lens group including a plurality of lenses arranged along an optical axis, a cylindrical lens barrel having an inner housing space for housing and holding the lens group, a sealing member that seals between the lens barrel and a first lens that is located closest to the object side of the lens group; and a sealing member that is provided on the lens barrel and is caulked inward in the radial direction to form the inner housing space. and a caulking portion for fixing the first lens of the lens group incorporated therein in the optical axis direction,
The lens group includes a second lens that contacts the first lens on the image side of the first lens, and one of the contact surfaces of the first lens and the second lens that contact each other. is provided with a recess, and this recess is filled with an airtight material that ensures airtightness between the first and second lenses.

In the present invention, there is a gap between the first lens and the second lens, which is a path that allows water vapor to enter into the lens unit. Since an airtight material is inserted between the contact surfaces of the first lens and the second lens that can guide water vapor into the interlens space, the sealing performance (waterproof performance) is improved by the sealing member located in the path. While ensuring that condensation is most likely to occur, the intrusion of water vapor into the space between the lenses, and furthermore, the intrusion of water vapor into the lens unit on the image side, is suppressed (improving airtightness). By reducing the amount of water vapor in the space, it is possible to suppress dew condensation on the lens surface, especially dew condensation on the image-side surface (back surface) of the first lens.

Furthermore, in the present invention, instead of interposing an airtight material between the contact surfaces of the first and second lenses to separate them, a recess is provided in the contact surface of the lens, and an airtight material is inserted into the recess. This not only helps to improve the airtightness between the lenses by ensuring that the lenses come into contact with each other, but also allows the distance between the lenses to be accurately maintained at the desired distance by making the lenses come into contact with each other. , it is possible to prevent the optical performance from being adversely affected by the insertion of the airtight material.

In addition, by filling the recess with an airtight material, the airtight material will not generate a reaction force in the optical axis direction against the crimping part through the lens, and will not have a negative effect on the crimping force (the crimping force will not be adversely affected). (It is possible to minimize the stress applied to the crimped part and increase the reliability of lens fixation by the crimped part). Further, from the viewpoint that the airtight material does not generate a reaction force against the caulking portion, it is preferable that the airtight material has a low elastic force.

Further, in relation to this reaction force, it is preferable that the sealing member (for example, an O-ring) is compressed in the radial direction between the first lens and the lens barrel. According to this, the elastic force (reaction force) of the crushed and elastically deformed sealing member does not act on the caulking portion in the optical axis direction and adversely affect the caulking force.

Further, in the above configuration, the sealing member and the airtight material may be integrally molded by two-color molding or the like (integral molding of members having different hardnesses). According to this, it is possible to improve the ease of assembling the seal member and the airtight material, and it is also possible to reduce the number of parts and reduce costs.

In the above configuration, the recess may have any form, such as a cutout-like groove, as long as the airtight material filled therein does not inhibit the contact state between the first and second lenses. It's okay. Further, such a concave portion may be provided on the abutting surface of the first lens that abuts the second lens, or may be provided on the abutting surface of the second lens that abuts the first lens. I don't mind.

Further, in the above configuration of the present invention, it is preferable that the hardness of the sealing member is higher than the hardness of the airtight material. According to this, it is possible to suppress the reaction force against the caulked portion due to the airtight material while improving the waterproof performance by the sealing member. Further, in this case, it is preferable that the sealing member is compressed in the radial direction so as not to generate a reaction force against the caulking portion as described above. Specifically, for example, in the case of an O-ring, the sealing member preferably has a hardness of 50 to 70 degrees and high elasticity in order to improve waterproof performance. On the other hand, an airtight material that does not require waterproof performance, such as rubber, may have a hardness of about 20 to 40 degrees.

Further, in the above configuration of the present invention, the airtight material may be a rubber material or an adhesive. In this case, an adhesive having a smaller reaction force than a rubber material is particularly preferred. Further, as the adhesive, from the viewpoint of low reaction force, an adhesive having high viscosity (for example, having a viscosity of about 62000 mPa·s) is more preferable. Note that other examples of the airtight material include Teflon and the like.

Further, in the above configuration of the present invention, the annular contact region where the first and second lenses contact each other at the contact surfaces and the annular airtight region where the recess is filled with an airtight material are arranged in the first and second lenses. Preferably, the second lens is located adjacent to the second lens in the radial direction. According to this arrangement of the contact area and the airtight area, good airtightness between the lenses can be effectively and efficiently achieved. In this case, the abutting area may be located on the radially inner side and the airtight area may be on the radially outer side, or the airtight area may be located on the radially inner side and the abutment area is on the radially outer side. You may.

Further, a camera module according to the present invention is characterized in that it includes the lens unit.
According to such a configuration, the effects of the above-mentioned lens unit can be obtained in the camera module.

According to the present invention, the recess provided in one of the contact surfaces of the first lens and the second lens that are in contact with each other is filled with an airtight material that ensures airtightness between the first and second lenses. Therefore, it is possible to suppress the intrusion of water vapor into the lens unit and prevent dew condensation on the lens surface.

1 is a schematic cross-sectional view of a lens unit according to an embodiment of the present invention. FIG. 2 is an enlarged view of main parts of the lens unit in FIG. 1. FIG. 2 is a schematic cross-sectional view of a camera module having the lens unit of FIG. 1. FIG. FIG. 2 is a schematic cross-sectional view showing an example of a conventional lens unit.

Embodiments of the present invention will be described below with reference to the drawings.
Note that the lens unit of this embodiment described below is particularly for use in a camera module such as an in-vehicle camera, and is, for example, installed fixedly on the outer surface of a car, and the wiring is drawn into the car. connected to a display or other device. Further, in all the figures including the above-mentioned FIG. 4, hatching for lenses is omitted.

FIG. 1 shows a lens unit 11 according to an embodiment of the invention. As shown in the figure, the lens unit 11 of the present embodiment includes a cylindrical lens barrel 12 made of resin, for example, and a plurality of lenses arranged in a stepped inner housing space S of the lens barrel 12. For example, it includes five lenses consisting of a first lens 13, a second lens 14, a third lens 15, a fourth lens 16, and a fifth lens 17 from the object side, and an aperture member 22. . In this embodiment, the aperture member 22 is inserted between the third lens 15 and the fourth lens 16, and limits the amount of transmitted light and determines the F value, which is an index of brightness. This is an aperture diaphragm or a shading diaphragm that blocks out light rays that cause ghosts and aberrations. An in-vehicle camera including such a lens unit 11 includes the lens unit 11, a substrate (not shown) having an image sensor, and an installation member (not shown) for installing the substrate in a vehicle such as an automobile.

A plurality of lenses 13, 14, 15, 16, and 17 that are incorporated and housed in the inner housing space S of the lens barrel 12 are stacked and arranged with their respective optical axes aligned. The lenses 13, 14, 15, 16, and 17 are arranged along one optical axis O, forming a lens group L used for imaging. In this case, the first lens 13 configuring the lens group L and located closest to the object side is a spherical glass lens having a convex surface (front surface 13d) on the object side and a concave surface (back surface 13e) on the image side, The second lens 14 is a resin lens that has a concave surface on the object side and a convex surface on the image side, and the other lenses 15, 16, and 17 are resin lenses, but are not limited to this (for example, the first It does not matter if the lens 13 is a resin lens).

The present invention including this embodiment is characterized by the airtight form formed on the contact surface between the first lens 13 and the second lens 14, and the number of lenses, the materials of the lenses and the lens barrel, etc. can be set arbitrarily depending on the purpose etc. Further, in this embodiment, the two fourth and fifth lenses 16 and 17 located on the image side are bonded lenses, but this need not be the case. It should be noted that the surfaces of these lenses 13, 14, 15, 16, and 17 are provided with an antireflection film, a hydrophilic film, a water-repellent film, etc., if necessary.

Further, in this embodiment, an O-ring 26 as a sealing member is inserted between the first lens 13 located closest to the object side and the lens barrel 12, and the lens group L inside the lens barrel 12 is inserted. This prevents water and dust from entering inside. In this case, the outer peripheral surface 13a of the first lens 13 is provided with a step-shaped reduced diameter part 13b whose diameter becomes smaller at the image side portion of the lens 13, and an O-ring 26 is attached to this reduced diameter part 13b. Then, the O-ring 26 is compressed in the radial direction between the outer peripheral surface 13a of the first lens 13 and the inner peripheral surface 12a of the lens barrel 12, so that the object side end of the lens barrel 12 is sealed. It is in a state. Note that the sealing member inserted between the first lens 13 and the lens barrel 12 is not limited to an O-ring, but may be any annular body that can seal between the first lens 13 and the lens barrel 12. It does not matter if it is in such a form.

Further, in the lens barrel 12, when the lens group L is installed and housed in the inner housing space S, the caulking portion 23 at the object side end (the upper end in FIG. 1) is radially inward. By being thermally caulked, the first lens 13 located closest to the object side of the lens group L is fixed to the object side end of the lens barrel 12 in the optical axis direction by the caulking portion 23 . In this case, in order to perform stable caulking, the portion of the glass lens 13 to which the caulking portion 23 is pressed is formed as a flat portion 13c cut obliquely into a plane.

Further, an inner flange portion 24 having an opening having a smaller diameter than the fifth lens 17 is provided at the image-side end (lower end in FIG. 1) of the lens barrel 12. A plurality of lenses 13, 14, 15, 16, 17 constituting the lens group L and the aperture member 22 are held and fixed in the optical axis direction within the lens barrel 12 by the inner flange portion 24 and the caulking portion 23. .

Further, as clearly shown in the enlarged view of FIG. 2, the first lens 13 of the lens group L is in contact with the second lens 14 in the optical axis direction on the image side, and the first lens 13 in the lens group L is in contact with the second lens 14 in the optical axis direction. One of the annular contact surfaces 13c and 14a of the lens 13 and the second lens 14, in this embodiment, the contact surface 14a of the second lens 14 is provided with an annular recess 14b in the form of a cutout groove, for example. It will be done. Therefore, the portion of the contact surface 14a with this annular recess 14b does not contact the contact surface 13c of the first lens 13. Further, the annular recess 14b extends from a portion of the first lens 13 facing the contact surface 13c to a portion facing the O-ring 26. In other words, the second lens 14 supports the first lens 13 while facing the contact surface 13c of the first lens 13, and extends outward in the radial direction from the contact surface 13c of the first lens 13. It has a support surface 14A that extends so as to project out, and this support surface 14A has a contact surface 14a that contacts the contact surface 13c of the first lens 13, and an annular recess 14b.

This annular recess 14b is filled with an airtight material 30 that ensures airtightness between the first and second lenses 13 and 14. Specifically, in this embodiment, the first lens is removed from a portion that is a path that allows water vapor to enter into the lens unit 11, that is, a gap between the caulked portion 23 of the lens barrel 12 and the first lens 13. into the inter-lens space S1 (defined by the image-side concave surface of the first lens 13 and the object-side convex surface of the second lens 14) formed between the first and second lenses 13 and 14. By fitting an annular rubber material as an airtight material 30 into the annular recess 14b by press-fitting or the like, between the contact surfaces 13c and 14a of the first lens 13 and the second lens 14 that can guide water vapor and Alternatively, the annular recess 14b is filled with adhesive as the airtight material 30.

In other words, in this embodiment, the annular contact area 40 where the first and second lenses 13 and 14 contact each other at the contact surfaces 13c and 14a, and the annular recess 14b filled with the airtight material 30. The airtight region 40 formed by the airtight material 30 abutting the abutting surface 13c of the first lens 13 while maintaining the abutting state of the abutting surfaces 13c, 14a is formed by the first and second lenses 13, 14 are located adjacent to each other along the radial direction. That is, in the present embodiment, during a path that can be a water vapor passage, that is, a path from the gap between the caulked portion 23 of the lens barrel 12 and the first lens 13 to the inter-lens space S1, A waterproof region 60 with an O-ring 26, an airtight region 50, and a contact region 40 are provided in this order from the side, and the waterproof region 60 and the airtight region 50 are positioned almost adjacent to each other along the optical axis O direction. In addition, since the airtight area 50 and the contact area 40 are located adjacent to each other along the radial direction of the lenses 13 and 14, the waterproofness and airtightness of this path are maintained at a high level.

Note that in this case, the hardness of the sealing member consisting of the O-ring 26 is set higher than the hardness of the airtight material 30. Specifically, for example, the O-ring 26 as a sealing member preferably has a hardness of 50 to 70 degrees and high elasticity in order to improve waterproof performance. On the other hand, if the airtight material 30 that does not require waterproof performance is, for example, a rubber material, the hardness is preferably about 20 to 40 degrees. Further, it is particularly preferable that the airtight material 30 is an adhesive having a smaller reaction force than a rubber material. As the adhesive, from the viewpoint of low reaction force, an adhesive having high viscosity (for example, having a viscosity of about 62000 mPa·s) is more preferable.

Further, FIG. 3 is a schematic cross-sectional view of a camera module 300 of this embodiment having the lens unit 11 configured as described above. As illustrated, this camera module 300 includes the lens unit 11 of FIG. 1 to which a filter 99 is attached.

The camera module 300 includes an upper case (camera case) 301 that is an exterior component, and a mount (pedestal) 302 that holds the lens unit 11. The camera module 300 also includes a seal member 303 and a package sensor (imaging device) 304.

The upper case 301 is a member that is engaged with a flange portion 25 provided in a brim shape on the outer circumferential surface 12b of the lens barrel 12, and exposes the object-side end of the lens unit 11 and covers other portions. The mount 302 is disposed inside the upper case 301 and has a female thread 302a that screws into the male thread 11a of the lens unit 11. The seal member 303 is a member inserted between the inner surface of the upper case 301 and the outer peripheral surface 12b of the lens barrel 12 of the lens unit 11, and is a member for maintaining airtightness inside the upper case 301. .

The package sensor 304 is disposed inside the mount 302 and is disposed at a position to receive an image of an object formed by the lens unit 11. Moreover, the package sensor 304 includes a CCD, CMOS, etc., and converts the light that is focused and reaches through the lens unit 11 into an electrical signal. The converted electrical signals are converted into analog data and digital data, which are constituent elements of image data taken by the camera.

As described above, according to the present embodiment, the portion that serves as a path for allowing water vapor to enter into the lens unit 11, that is, the portion between the caulked portion 23 of the lens barrel 12 and the first lens 13. An airtight material is placed between the contact surfaces 13c and 14a of the first lens 13 and the second lens 14, which can introduce water vapor from the gap into the interlens space S1 between the first and second lenses 13 and 14. 30 is inserted, while ensuring sealing performance (waterproofing performance) with the O-ring 26 located in the path, it prevents water vapor from entering the interlens space S1 where dew condensation is most likely to occur, and further toward the image side. This suppresses the intrusion of water vapor into the lens unit 11 (improves airtightness), reduces the amount of water vapor in the inter-lens space S1, and prevents condensation on the lens surface, especially on the image-side back surface of the first lens 13. It is possible to suppress the formation of dew condensation on 13e.

Further, according to the present embodiment, the airtight material 30 is not inserted between the contact surfaces 13c and 14a of the first and second lenses 13 and 14 to separate them, but the second lens 14 An annular recess 14b is provided on the abutment surface 14a of the lens, and this annular recess 14b is filled with an airtight material 30, thereby ensuring that the lenses 13 and 14 are in contact with each other, contributing to improving the airtightness between the lenses 13 and 14. Not only this, but also the contact between the lenses 13 and 14 allows the distance between the lenses to be accurately maintained at a desired distance, and it is possible to prevent the insertion of the airtight material 30 from adversely affecting optical performance.

Furthermore, if the annular recess 14b is filled with the airtight material 30, the airtight material 30 will not generate a reaction force in the optical axis direction against the caulking part 23 via the first lens 13, and the caulking force will be reduced. (The stress applied to the caulking portion 23 can be minimized and the reliability of lens fixation by the caulking portion 23 can be increased.)

Further, according to the present embodiment, since the O-ring 26 is compressed in the radial direction between the first lens 13 and the lens barrel 12, the elastic force of the O-ring 26 that is crushed and elastically deformed is (Reaction force) does not act on the caulking portion 23 in the optical axis direction and adversely affect the caulking force.

Further, according to the present embodiment, since the hardness of the O-ring 26 is set higher than the hardness of the airtight material 30, while the waterproof performance is enhanced by the O-eng 26, the resistance against the caulking portion 23 due to the airtight material 30 is increased. force can be suppressed.

Further, according to the present embodiment, the contact area 40 where the first and second lenses 13, 14 contact each other at the contact surfaces 13c, 14a, and the airtight material 30 filled in the annular recess 14b are provided. Since the region 50 is located adjacent to the first and second lenses 13 and 14 in the radial direction, good airtightness between the lenses 13 and 14 can be effectively and efficiently achieved.

Note that the present invention is not limited to the embodiments described above, and can be implemented with various modifications without departing from the gist thereof. For example, in the present invention, the shapes of lenses, lens barrels, etc. are not limited to the embodiments described above. Further, in the embodiment described above, the contact area 40 is located on the inside in the radial direction and the airtight area 50 is located on the outside in the radial direction, but the airtight area 50 is located on the inside in the radial direction and Region 40 may be located radially outward. Further, in the embodiment described above, the annular recess was provided on the contact surface 14a of the second lens 14 that contacts the first lens 13; An annular recess may be provided in the abutting surface 13c. Further, in the embodiment described above, the recess is formed as a notched annular groove, but the airtight material filled in the recess does not inhibit the contact state between the first and second lenses. Any form may be used as long as it is in any form. In addition, in the embodiment described above, the sealing member (O-ring 26) and the airtight material 30 are separate members, but the sealing member and the airtight material are integrally formed by two-color molding or the like (members with different hardnesses). may be integrally molded). According to this, it is possible to improve the ease of assembling the seal member and the airtight material, and it is also possible to reduce the number of parts and reduce costs. Further, in the above-described embodiment, the recessed portion has an annular shape, but it does not need to be annular, and the shape and arrangement of the recessed portion can be set arbitrarily. In short, it is sufficient if the airtight area and the contact area can suppress (prevent) the intrusion of water vapor into the interlens space.

11 Lens unit 12 Lens barrel 13 First lens 13c Contact surface 14 Second lens 14a Contact surface 14b Annular recess (recess)
26 O-ring (sealing member)
30 Airtight material 40 Contact area 50 Airtight area 300 Camera module L Lens group O Optical axis S Inner housing space S1 Space between lenses

Claims (4)

a lens group consisting of a plurality of lenses arranged along the optical axis; a cylindrical lens barrel having an inner housing space for housing and holding the lens group; a sealing member for sealing between a first lens made of glass and the lens barrel; and a sealing member for sealing between a first lens made of glass and the lens barrel; A lens unit having a caulking portion for fixing the first lens in the optical axis direction,
The lens group includes a second lens that comes into contact with the first lens on the image side of the first lens,
Both the first lens and the second lens are fitted into the inner circumferential surface of the lens barrel,
An image side surface of the first lens and an object side surface of the second lens are each provided with a flat surface,
The flat surface of the first lens and a portion of the flat surface of the second lens are in contact with each other,
A concave portion is provided in one of the flat abutment surfaces of the first lens and the second lens that abut each other, and the concave portion includes an airtight gap between the first and second lenses. Filled with airtight material to ensure
the airtight material abuts the other contact surface;
A continuous annular contact area in which the first and second lenses abut on the contact surfaces, and a continuous annular airtight area in which the recess is filled with the airtight material, A lens unit characterized in that the first and second lenses are located adjacent to each other along the radial direction. The lens unit according to claim 1, wherein the hardness of the sealing member is higher than the hardness of the airtight material. 3. The lens unit according to claim 1, wherein the airtight material is a rubber material or an adhesive. A camera module comprising the lens unit according to any one of claims 1 to 3.

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