JP2019109381A - Lens unit and camera module - Google Patents

Abstract

To provide a lens unit and a camera module that can obtain a desired optical characteristic adapted to desired working temperature by suppressing looseness or deformation of a lens at a low temperature and a high temperature.SOLUTION: A lens unit 11 according to the present invention has an elastic member 40 interposed at least between lenses 13 and 14. The elastic member can absorb deformation in an optical axis direction of the lens, accompanied by temperature change.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a lens unit and a camera module which particularly constitute an on-vehicle camera mounted on a vehicle such as a car.

  In recent years, an on-vehicle camera has been mounted on a car to support parking and to prevent collisions by image recognition, and attempts are also being made to apply it to automatic driving. In addition, a camera module such as such a car-mounted camera generally includes a lens group formed by arranging a plurality of lenses along an optical axis, a barrel for housing and holding the lens group, and at least the lens group. And a lens unit having an iris member disposed between the lenses at one point (for example, see Patent Document 1).

  Then, in this lens unit, a plurality of lenses are incorporated in the lens barrel so as to be stacked, and finally, a cap is attached to the object end of the lens barrel, or the object end of the lens barrel is crimped. Thus, a lens group composed of lenses of a laminated structure is held in the optical axis direction in the lens barrel.

JP, 2013-231993, A

  By the way, in the state in which the lenses are stacked and incorporated in the lens barrel as described above, one problem occurs particularly when using a combination of a metal lens barrel and a resin lens. That is, since there is a difference between the metal and the resin in linear expansion coefficient (coefficient of thermal expansion), for example, under a low temperature environment, the lens largely shrinks relative to the lens barrel, for example, A gap is created in the lens, and the lens rattles in the optical axis direction. On the other hand, in a high temperature environment, compressive stress acts on the lens due to thermal expansion of the lens inside the lens barrel, in particular. is there. In particular, when the position of the contact fulcrum between the lenses supporting each other is different between the lenses, the displacement of the contact fulcrum and the stress concentration occurring at the contact fulcrum combine. In particular, a lens having a recess on the radially inner side is easily deformed radially inward by being pushed down on one side of the object side and the image side (image forming side) and pushed up on the other side.

  Such low-temperature lens rattling causes a deterioration in resolution due to a change in the distance between lens surfaces, and deformation of the lens at high temperatures may result in the failure of achieving desired resolution performance or defocusing. Etc., which adversely affect the optical properties, which makes the lens unit incompatible with its use temperature.

  The present invention has been made in view of the above-mentioned circumstances, and a lens unit capable of obtaining desired optical characteristics adapted to a desired use temperature by suppressing rattling and deformation of the lens at low and high temperatures. It aims at providing a camera module.

  In order to solve the above problems, according to the present invention, a cylindrical lens barrel forming an inner housing space for housing and holding a lens, and a plurality of lenses stacked in the inner housing space of the lens barrel are stacked. And a lens unit arranged along the optical axis, and an elastic member is provided between the lenses and / or between the lens and the lens barrel or the lens barrel side member. It is characterized by being inserted.

  In the present invention, since the elastic member is inserted in at least one of the lens, or between the lens and the lens barrel or the lens barrel side member, the elastic member causes an optical axis direction of the lens accompanying temperature change by the elastic member. Can absorb the deformation of the lens, so that there is a difference in the coefficient of thermal expansion (coefficient of thermal expansion) between the lens barrel and the lens, especially when the lens barrel is made of metal and the lens is made of resin. Even if the temperature is low and the temperature is high, rattling and deformation of the lens can be suppressed to obtain desired optical characteristics compatible with the desired use temperature.

  That is, in a low temperature environment, the contraction of the lens causes a gap, in particular, between the lenses, and even if the lens tends to rattle in the optical axis direction, the elastic member absorbs the rattling. (Which can absorb shrinkage deformation and the rattling associated therewith), thus preventing the reduction in resolution due to the change in the distance between the surfaces of the lenses. On the other hand, in a high temperature environment, compressive stress is applied to the lens by thermal expansion of the lens especially inside the lens barrel, and even if the surface shape of the lens is to be deformed, such deformation may be absorbed by the elastic member it can. Therefore, it is possible to prevent the lens unit from becoming incompatible with the use temperature due to adverse effects on the optical characteristics such as the desired resolution performance being not obtained or the focal point being shifted due to the deformation of the lens.

In the above configuration of the present invention, the lens group constitutes a wide-angle lens, and the elastic member is interposed between the first lens located closest to the object side and the second lens adjacent to the first lens. Is preferred. In the wide-angle lens, the inter-plane sensitivity as the degree to which the change in the distance between the lens surfaces affects the resolution is as dull as that of the lens on the object side, and thus the first lens positioned closest to the object and the first lens By inserting an elastic member between the lens and the second lens adjacent to the lens of the lens, it is possible to effectively absorb the deformation of the lens in the optical axis direction accompanying the temperature change without substantially affecting the optical characteristics (resolution). It is useful.
In the present specification, a wide-angle lens refers to a lens that satisfies, for example, an angle of view of 160 ° or more.

  Further, in the above configuration of the present invention, the elastic member interposed between the first lens located closest to the object side and the second lens adjacent to the first lens is the first lens and the mirror. It is preferable that the light shielding member is formed as a light shielding member having a sealing function that extends further between the cylinder and seals the space between the first lens and the lens barrel from the outside. In such a configuration, it is possible not only to dispense with the so-called redaction processing of painting the lens in order to suppress the phenomenon such as ghost and flare, but also by providing the elastic member having the above-mentioned operational effects. There is no need to interpose a sealing member such as an O-ring or the like for sealing the inner housing space from the outside between the lens and the lens barrel. Therefore, the number of members can be reduced, the manufacturing process can be simplified, and further, the lens unit can be miniaturized.

Further, a camera module according to the present invention is characterized by comprising the lens unit.
According to such a configuration, the function and effect of the above-described lens unit can be obtained by the camera module.

  According to the present invention, the elastic member for absorbing the deformation in the optical axis direction of the lens accompanying the temperature change is interposed between the lenses and / or between the lens and the lens barrel or the lens barrel side member. Because the lens barrel is made of metal and the lens is made of resin, even if there is a difference in the coefficient of thermal expansion (coefficient of thermal expansion) between the lens barrel and lens By suppressing rattling and deformation of the lens at times, it is possible to obtain desired optical characteristics that match the desired operating temperature.

FIG. 1 is a schematic cross-sectional view of a lens unit according to a first embodiment of the present invention. It is a schematic sectional drawing of the lens unit which concerns on the 2nd Embodiment of this invention. It is a schematic sectional drawing of the lens unit which concerns on the 3rd Embodiment of this invention. It is a schematic sectional drawing of the lens unit which concerns on the 4th Embodiment of this invention. FIG. 1 is a schematic cross-sectional view of a camera module having a lens unit according to a first embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The lens unit according to the present embodiment described below is especially for a camera module such as a car-mounted camera, and is fixedly installed on the outer surface side of a car, for example, and the wiring is drawn into the car Connection to a display or other device. Further, hatching is omitted for a plurality of lenses in FIGS. 1 to 5.

  FIG. 1 shows a lens unit 11 according to a first embodiment of the present invention. As illustrated, the lens unit 11 of the present embodiment includes, for example, a cylindrical barrel 12 made of metal, and a plurality of lenses disposed in the stepped inner accommodation space S of the barrel 12; For example, 7 from the object side, the first lens 13, the second lens 14, the third lens 15, the fourth lens 16, the fifth lens 17, the sixth lens 18 and the seventh lens 19 And a diaphragm member 22. In the present embodiment, the diaphragm member 22 is interposed between the third lens 15 and the fourth lens 16, limits the amount of transmitted light, and determines an F value as an index of brightness. An “aperture stop” or “a light blocking stop” that blocks a ray causing a ghost or a ray causing an aberration. An on-vehicle camera including such a lens unit 11 includes the lens unit 11, a substrate having an image sensor (not shown), and an installation member (not shown) for installing the substrate on a vehicle such as a car.

  The plurality of lenses 13, 14, 15, 16, 17, 18 and 19 incorporated and housed in the inner housing space S of the lens barrel 12 are stacked and arranged with their optical axes aligned. , And the lenses 13, 14, 15, 16, 17, 18, 19 are arranged along one optical axis O to constitute one lens group L used for imaging. . In particular, in the present embodiment, the lens unit L constitutes, for example, a wide angle lens having a field angle of 195 °, and in this case, for example, the first lens 13 is a lens made of a glass spherical surface having negative power. The second lens 14 is a resin lens having negative power, the third lens 15 is a resin lens having positive power, and the fourth lens 16 is a glass lens having positive power, the fifth Lens 17 is a resin lens having a negative power, the sixth lens 18 is a resin lens having a positive power, and the seventh lens 19 is a resin lens having a positive power, but is limited thereto I will not. The present invention including the present embodiment is characterized by an elastic member to be described later, and the number of lenses, materials of lenses and barrels, positive / negative of power of lenses, etc. can be arbitrarily set according to applications etc. The group does not have to constitute a wide-angle lens. Also, in the present embodiment, the two fifth and sixth lenses 17 and 18 positioned on the image side are cemented lenses, but this is not necessary. In addition, an antireflective film, a hydrophilic film, a water repellent film, etc. are provided on the surface of these lenses 13, 14, 15, 16, 17, 18, 19 as necessary.

  A cap 23 is screwed to the end (the upper end in FIG. 1) of the lens barrel 12 on the object side, and the first lens 13 positioned on the most object side of the lens unit L by the cap 23 is a lens barrel It is fixed to the end on the 12 object side. Of course, the first lens 13 may be fixed to the object-side end of the lens barrel 12 by caulking the object-side end of the lens barrel 12 radially inward.

  Further, an inner flange portion 24 having an opening smaller in diameter than the seventh lens 19 is provided at an end (lower end in FIG. 1) of the lens barrel 12 on the image side (image forming side). The plurality of lenses 13, 14, 15, 16, 17, 18 and 19 constituting the lens unit L in the lens barrel 12 and the aperture member 22 are held in the optical axis direction by the inner flange portion 24 and the cap 23. It is fixed.

  An O-ring 26 as a seal member is provided between the lens barrel 12 and the surface facing the image side of the first lens 13 positioned closest to the object side, and the object side of the lens barrel 12 is provided between them. Sealed at the end. This prevents the entry of fine particles such as water and dust into the lens barrel 12 from the end of the lens unit 11 on the object side. In the outer peripheral surface of the lens barrel 12, an outer flange portion 25 used when the lens barrel 12 is installed in a vehicle-mounted camera is provided in a bowl shape on the outer peripheral surface of the lens barrel 12.

  Further, as shown in FIG. 1, the lens unit 11 of the present embodiment is provided with an annular elastic member 40 for absorbing the deformation in the optical axis direction of each lens due to the temperature change. In the present embodiment, in particular, the influence on the imaging performance due to the installation of the elastic member 40 is reduced, and the outside flange portion 25 and the camera module 300 described later are obtained from the package sensor (image sensor) 304 described later (see FIG. 5). The first lens 13 positioned closest to the object side in order to keep the optical distance of the lens unit L up to the connection position with the upper case 301 (see FIG. 5) constant (do not mechanically displace) An elastic member 40 is interposed between the second lens 14 adjacent to the first lens 13.

  Such an elastic member 40 is made of a rubber sheet, a wave washer, a plate spring or the like, and in the present embodiment, the thickness (dimension in the optical axis direction) of the elastic member 40 is set to 0.25 mm, for example. In addition, as the elastic member 40 is shown also by the 2nd-4th embodiment mentioned later, the installation position is not limited between the 1st lens 13 and the 2nd lens 14, A temperature change is carried out The installation position is determined so that the optical distance becomes constant based on the total sum of the amount of deformation of the entire optical system (lens group L) and the amount of deformation of the entire lens barrel 12 involved. In particular, when the lens unit L configures a wide-angle lens as in the present embodiment, the inter-plane sensitivity as the degree that the change in distance between lens surfaces affects the resolution is as dull as the lens on the object side If the elastic member 40 is interposed between the first lens 13 and the second lens 14 positioned closest to the object side, the lens accompanying the temperature change with almost no influence on the optical characteristics (resolution). It can effectively absorb deformation in the optical axis direction, which is useful.

  FIG. 2 shows a second embodiment of the present invention. As illustrated, in the lens unit 11A of the present embodiment, the above-described annular elastic member 40 for absorbing the deformation in the optical axis direction of each lens caused by the temperature change is the first lens 13 and the cap (lens barrel It is inserted between the side members 23. Such a position is preferable because it has a distance from the image sensor 304 and there is no need to consider the sensitivity between the surfaces of the lens, so the installation space is limited but the effect on the optical characteristics is small.

  FIG. 3 shows a third embodiment of the present invention. As illustrated, in the lens unit 11B of the present embodiment, the above-described annular elastic member 40 for absorbing the deformation in the optical axis direction of each lens accompanying the temperature change is the seventh lens 19 and the lens barrel 12 Is inserted between In such a position, the entire optical system (lens group L) is displaced due to the elastic deformation of the elastic member 40, so it is necessary to consider that point, but the installation space can be stably secured large. It is useful.

  FIG. 4 shows a fourth embodiment of the present invention. As illustrated, in the lens unit 11C of the present embodiment, the above-described annular elastic member for absorbing the deformation in the optical axis direction of each lens accompanying the temperature change is the same as in the first embodiment, The elastic member 40A is further extended between the first lens 13 and the lens barrel 12 though interposed between the first lens 13 and the second lens 14 positioned closest to the object side. The light shielding member has a sealing function of sealing between the first lens 13 and the lens barrel 12 from the outside.

  In such a configuration, it is possible not only to dispense with the so-called redaction processing of painting the lens in order to suppress the phenomenon such as ghost and flare, but also by providing the elastic member having the above-mentioned operational effects. It is not necessary to insert a seal member such as the above-mentioned O-ring 26 or the like for sealing the inner accommodation space S of 12 from the outside between the lens 13 and the lens barrel 12. Therefore, the number of members can be reduced, the manufacturing process can be simplified, and the lens unit 11 can be miniaturized. As a material of the elastic member 40A having such sealing function and light shielding function, for example, EPDM (ethylene propylene diene rubber) can be mentioned, and its thickness (dimension in the optical axis direction) is, for example, 0.25 mm. It can be set.

  FIG. 5 is a schematic cross-sectional view of a camera module 300 according to the present embodiment having a lens unit configured as described above. As illustrated, this camera module 300 is configured to include the lens unit 11 according to the first embodiment of FIG. 1 to which the filter 100 is attached, but the second to fourth of FIG. The lens units 11A, 11B, and 11C according to the embodiment may be configured.

  The camera module 300 includes an upper case (camera case) 301 which is an exterior component, and a mount (base) 302 for holding the lens unit 11. The camera module 300 further includes a seal member 303 and a package sensor (imaging element) 304.

  The upper case 301 is a member that exposes the end portion on the object side of the lens unit 11 and covers the other portion. The mount 302 is disposed inside the upper case 301 and has an internal thread 302 a screwed with the external thread 11 a of the lens unit 11. The seal member 303 is a member interposed between the inner surface of the upper case 301 and the outer peripheral surface 12 a of the lens barrel 12 of the lens unit 11, and is a member for maintaining the 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. Further, the package sensor 304 is provided with a CCD, a CMOS or the like, and converts the light condensed and reached through the lens unit 11A into an electric signal. The converted electrical signal is converted into analog data or digital data which is a component of image data captured by a camera.

  As described above, in the first to fourth embodiments described above, the elastic member 40 (40A) for absorbing the deformation in the optical axis direction of the lens accompanying the temperature change is an inter-lens and / or lens In particular, the lens barrel 12 is formed of metal and the lenses 13 to 19 are formed of resin, as in the embodiment described above, because the lens 13 is inserted between the lens barrel 12 and the lens barrel side member 23. Even if there is a difference in the coefficient of thermal expansion (coefficient of thermal expansion) between the lens barrel 12 and the lenses 13 to 19 as desired, it is desirable to suppress rattling and deformation of the lenses 13 to 19 at low temperatures and high temperatures. It is possible to obtain the desired optical properties compatible with the use temperature of

  That is, in a low temperature environment, a contraction of the lens causes a gap particularly between the lenses, and even if the lens rattles in the optical axis direction, the rattling can be absorbed by the elastic member 40 (40A). Therefore, it is possible to prevent the reduction in resolution due to the change in the inter-plane distance of the lens. On the other hand, in a high temperature environment, compressive stress acts on the lens due to thermal expansion of the lens inside the lens barrel 12 in particular, and even if the surface shape of the lens tends to be deformed, such deformation is made by the elastic member 40 (40A) Can be absorbed by Therefore, it is possible to prevent the lens unit from becoming incompatible with the use temperature due to adverse effects on the optical characteristics such as the desired resolution performance being not obtained or the focal point being shifted due to the deformation of the lens.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, in the present invention, the shapes of the lens, the lens barrel, and the like are not limited to the embodiments described above. Further, the elastic member only needs to be able to absorb the deformation in the optical axis direction of the lens due to the temperature change, and the shape, installation form and the like can be set arbitrarily. Further, the first to fourth embodiments described above may be realized individually, but may be realized in combination.

11, 11A, 11B, 11C Lens Unit 12 Lens Barrel 13, 14, 15, 16, 17, 18, 19 Lens 23 Cap (lens barrel side member)
40, 40A Resilient member 300 Camera module O Optical axis S Inner housing space

Claims (5)

A cylindrical barrel forming an inner accommodation space for accommodating and holding the lenses, and the inner barrel of the lens barrel are incorporated in the inner accommodation space and arranged along the optical axis so that a plurality of lenses are stacked. A lens unit comprising a lens group,
A lens unit characterized in that an elastic member is interposed between the lenses and / or between the lens and the lens barrel or the lens barrel side member.   The lens unit according to claim 1, wherein the lens barrel is made of metal, and the lens is made of resin.   The lens group constitutes a wide-angle lens, and the elastic member is interposed between a first lens located closest to the object side and a second lens adjacent to the first lens. The lens unit according to claim 1 or 2.   The elastic member is formed as a light shielding member having a sealing function which further extends between the first lens and the lens barrel and seals the space between the first lens and the lens barrel from the outside. The lens unit according to claim 3, characterized in that:   A camera module comprising the lens unit according to any one of claims 1 to 4.

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