JP6054819B2 - Lens unit, imaging device, and moving body - Google Patents

Description

  The present invention relates to a lens unit, an imaging device, and a moving body having a waterproof function while suppressing manufacturing costs.

  There are known cameras that are frequently exposed to the outdoor environment, such as in-vehicle cameras and surveillance cameras. The lens unit used for such an outdoor camera is required to have improved waterproofness.

  In order to provide high waterproof performance, an image is formed in which a ring circular flat portion is formed around the lens and the lens is fixed in the lens barrel from the object side by a pressing member having a ring-shaped stepped portion facing the flat portion. An apparatus has been proposed (see Patent Document 1).

JP 2005-017951 A

  However, in the imaging apparatus described in Patent Document 1, lenses other than the first lens arranged closest to the object side are pressed into the lens barrel by the pressing member via the first lens. However, in the configuration in which the first lens is pressed by directly contacting the internal lens, the molding accuracy of the first lens 20 or the second lens 21, that is, if the contact between the two is not a surface contact, the fixing is unstable. Become. Therefore, it is difficult to improve the accuracy of the mounting position or posture of the lens group including the first lens and the internal lens.

  Accordingly, an object of the present invention made in view of such circumstances is to provide a lens unit, an imaging device, and a moving body in which the mounting position and posture of a lens group are improved.

In order to solve the above-described problems, the lens unit according to the first aspect is
A lens group including at least a first lens and a second lens;
It has a cylindrical shape and holds the lens group to be disposed from the object side along the central axis of the cylindrical in order of the first lens and the second lens inside the cylindrical mirror A tube,
A pressing member that fixes the lens group inside the lens barrel by pressing the first lens into the lens barrel;
An elastic member interposed between the first lens and the second lens ,
The elastic member is elastically deformed by the pressing of the first lens by the pressing member , and is interposed between the first part that presses the second lens, and the first part and the second lens. It has a thin part thinner than the minimum value of the generated gap, and a second part that continues to the first lens through the thin part .

In the lens unit according to the second aspect,
It is preferable that the elastic member is in close contact with the inner surface of the first lens, the second lens, and the lens barrel during elastic deformation due to the pressing of the first lens.

In the lens unit according to the third aspect,
It is preferable that the first lens and the lens barrel have a structure in surface contact with each other by pressing from the pressing member.

In the lens unit according to the fourth aspect,
The elastic member preferably has a light shielding property.

In the lens unit according to the fifth aspect,
The second site, which is preferably released from the pressing of the pressing member positioned on the optical axis side through the first lens of the first lens than the previous SL first site.

An imaging device according to a sixth aspect is
A lens group including at least a first lens and a second lens, and a cylindrical shape, and the first lens and the second lens are arranged from the outermost side along the height direction of the cylindrical shape. A lens barrel that holds the lens group inside the cylindrical shape, a pressing member that fixes the lens group inside the lens barrel by pressing the first lens into the lens barrel, and the first A lens unit that is interposed between the second lens and the second lens and has an elastic member that presses the second lens while being elastically deformed by the pressing of the first lens by the pressing member, and the lens The unit includes an image pickup device that picks up a subject image formed by the unit.

In the imaging device according to the seventh aspect,
It is preferable that the image sensor further includes an output unit that outputs an image signal generated by capturing the subject.

In addition, the moving object according to the eighth aspect is
A lens group including at least a first lens and a second lens, and a cylindrical shape, and the first lens and the second lens are arranged from the outermost side along the height direction of the cylindrical shape. A lens barrel that holds the lens group inside the cylindrical shape, a pressing member that fixes the lens group inside the lens barrel by pressing the first lens into the lens barrel, and the first A lens unit that is interposed between the second lens and the second lens and has an elastic member that presses the second lens while being elastically deformed by the pressing of the first lens by the pressing member, and the lens A moving body having an image pickup device including an image pickup device that picks up an image of a subject formed by the unit, wherein the image pickup device is installed outside the moving body so that the periphery of the moving body can be picked up. It is characterized by that.

  According to the lens unit, the imaging device, and the moving body according to the present invention configured as described above, the mounting position and posture of the lens group can be improved.

FIG. 3 is a layout diagram illustrating an installation location in the moving body of the imaging apparatus having the lens unit according to the first embodiment of the present invention. It is sectional drawing along the optical axis of the lens unit in FIG. FIG. 3 is a cross-sectional view of the first lens in FIG. 2 along the optical axis. It is sectional drawing along the central axis of the lens-barrel in FIG. It is sectional drawing along the central axis of the elastic member in FIG. It is sectional drawing along the optical axis of the lens unit which fixes a 1st lens using a spacer and an O-ring.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  First, an imaging apparatus having a lens unit according to an embodiment of the present invention will be described. FIG. 1 is a layout diagram showing a mounting position of a moving body 12 of an imaging apparatus 11 having a lens unit 10 according to the present embodiment. The imaging device 11 is an in-vehicle camera, for example. The moving body 12 is a vehicle such as an automobile.

  As shown in FIG. 1, the imaging device 11 having the lens unit 10 is provided on the moving body 12 together with the display device 13. The imaging device 11 is installed outside the moving body 12 and can image the periphery of the moving body 12. In the present embodiment, the imaging device 11 is fixed to the outside of the rear of the moving body 12 in order to capture a peripheral image of the rear view, for example. The display device 13 is provided so as to be visible from the driver's seat.

  The lens unit 10 forms a subject image behind the moving body 12 on the imaging element 14 in the imaging device 11. The imaging device 11 captures a subject image using the imaging element 14 and generates an image signal. Further, the imaging device 11 outputs an image signal to the display device 13 via the output unit 15. The display device 13 displays a subject image corresponding to the image signal acquired from the output unit 15.

  The configuration of the lens unit 10 will be described with reference to FIG. FIG. 2 is a cross-sectional view of the lens unit 10 along the optical axis. The lens unit 10 includes a lens group 16, a lens barrel 17, a pressing member 18, and an elastic member 19.

  The lens group 16 includes a plurality of optical elements including at least the first lens 20 and the second lens 21. In the present embodiment, the lens group 16 includes a first lens 20 and a second lens 21. In the lens group 16, one along the optical axis OX is defined on the object side, and the other is defined on the imaging side. The first lens 20 and the second lens 21 are arranged in order from the object side direction. Each optical element is formed and combined so that the lens group 16 has desired optical characteristics such as a focal length and a depth of field in combination with an elastic member 19 described later.

  As shown in FIG. 3, the first lens 20 has a lens effective surface portion 20L and a contact surface portion 20C in the image forming side direction. The lens effective surface portion 20L has, for example, a concave shape. The contact surface portion 20C is a surface that can intersect the optical axis OX of the first lens 20 that is optically aligned with the lens group 16, and is, for example, a plane perpendicular to the optical axis OX. The outer diameter of the first lens 20 is larger than the outer diameter of the second lens 21.

  As shown in FIG. 4, the lens barrel 17 has a housing portion 22 and a presser portion 23. In the lens barrel 17, one along the central axis CX is defined as the object side, and the other is defined as the imaging side.

  The accommodating portion 22 is formed rotationally symmetrical with respect to the central axis CX1, that is, in a cylindrical shape. The accommodating portion 22 holds the lens group 16 therein so that the first lens 20 and the second lens 21 are arranged from the outermost side on the object side along the central axis CX1, that is, the height direction of the cylindrical shape. To do. The accommodating portion 22 has a first accommodating portion 24 that accommodates the first lens 20 and a second accommodating portion 25 that accommodates the second lens 21 in order from the object side. The inner diameter of the first housing portion 24 is substantially equal to the outer diameter of the first lens 20 and may have a minute gap when the first lens 20 is fitted. Further, the inner diameter of the second housing part 25 is substantially equal to the outer diameter of the second lens 21, and has a minute gap when the second lens 21 is fitted. The inner surface of the part connecting the first accommodation part 24 and the second accommodation part 25 has a contact surface part 22C. The contact surface portion 22 </ b> C of the housing portion 22 can come into surface contact with the contact surface portion 20 </ b> C of the first lens 20.

  The presser portion 23 is formed at an end portion on the image forming side of the second accommodation portion 25. The presser part 23 has a plane perpendicular to the central axis CX <b> 1 inside, and fixes the lens group 16 in the housing part 22 from the imaging side in a state of surface contact with the second lens 21. The presser portion 23 has an opening centered on the central axis CX1 and can transmit light transmitted through the lens group 16.

  The pressing member 18 (see FIG. 2) fixes the lens group 16 inside the lens barrel 17 by pressing the first lens 20 into the lens barrel 17 from the object side. The pressing member 18 is, for example, a retainer, and can press the first lens 20 into the lens barrel 17 from the object side by being screwed with the first accommodating portion 24 of the lens barrel 17.

  The elastic member 19 is formed of a material having elasticity and light shielding properties, and has an annular shape as shown in FIG. The elastic member 19 has a first portion 26, a thin portion 27, and a second portion 28. The 1st site | part 26, the thin part 27, and the 2nd site | part 28 are each cyclic | annular. As shown in FIG. 2, the image forming side of the first portion 26 is formed so as to be in surface contact with the object side surface of the second lens 21. The outer diameter of the first part 26 is substantially equal to the inner diameter of the second accommodation part 25 of the lens barrel 17 and has a small gap when the elastic member 19 is accommodated in the second accommodation part 25. obtain. The inner diameter of the first part 26 is larger than the inner diameter of the second part 28 (see FIG. 5). The second portion 28 functions as an aperture stop in the lens unit 10, and the inner diameter is determined so as to satisfy desired optical characteristics of the lens unit 10 as described above. The first part 26 and the second part 28 are formed in a shape in which the central axes CX <b> 2 coincide with each other and continue through the thin portion 27.

  In the manufacture of the lens unit 10, the second lens 21 is accommodated in the second accommodating portion 25 from the object side of the lens barrel 17 (see FIG. 2). In a state where the second lens 21 is fixed by the pressing portion 23 of the lens barrel 17, the elastic member 19 is arranged such that the optical axis OX of the lens group 16 and the central axis CX2 coincide with each other and the second portion 28 faces the object side. Is brought into contact with the second lens 21. The first portion 26 of the elastic member 19 protrudes toward the object side from the contact surface portion 22 </ b> C of the lens barrel 17 in contact with the second lens 21. In this state, the first lens 20 is brought into contact with the first portion 26 of the elastic member 19. With the first lens 20 in contact with the elastic member 19, the first lens 20 is pressed into the lens barrel 17 by the presser member 18. The first portion 26 of the elastic member 19 receives pressure from the first lens 20 and is elastically deformed. Due to the elastic deformation of the first part 26, the elastic member 19 comes into close contact with the first lens 20, the second lens 21, and the second housing part 25 of the lens barrel 17. The first lens 20 is pressed by the pressing member 18 toward the imaging side until the contact surface portion 20C of the first lens 20 and the contact surface portion 22C of the lens barrel 17 come into surface contact. In a state where the first lens 20 and the lens barrel 17 are in surface contact, a gap is generated between the first lens 20 and the second lens 21, and the thin portion 27 of the elastic member 19 is thinner than the minimum value of the gap. . In addition, in a state where the first lens 20 and the lens barrel 17 are in surface contact, the second portion 28 of the elastic member 19 is released from pressing from both the first lens 20 and the second lens 21. Keep the original shape.

  According to the lens unit of the present embodiment having the above-described configuration, the elastic member 19 presses the second lens 21 while being elastically deformed by the pressing of the pressing member 18. Can be improved.

  Further, according to the lens unit of the present embodiment, the elastic member 19 is in close contact with the inner surfaces of the first lens 20, the second lens 21, and the lens barrel 17 during the elastic deformation caused by the pressing of the first lens 20. The waterproofing inside the lens unit 10 is possible.

  Further, according to the lens unit of the present embodiment, the first lens 20 and the lens barrel 17 are brought into surface contact by pressing from the pressing member 18, so that the accuracy of the mounting posture of the first lens 20 can be further improved. It is. In particular, since the first lens 20 can be brought into surface contact on the radially outer side than the position in contact with the elastic member 19, the accuracy of the mounting posture can be further improved.

  Further, according to the lens unit of the present embodiment, since the elastic member 19 has a light shielding property, even when there is a gap between the first lens 20 and the second lens 21, the passage of unnecessary light rays is prevented. Therefore, stray light can be reduced.

  Further, according to the lens unit of the present embodiment, the elastic member 19 is released from the pressing of the pressing member 18 at the second portion 28, and can function as an aperture stop. Therefore, it is not necessary to provide an aperture stop separately, the number of parts is reduced, and the manufacturing cost is reduced.

  Further, the following configuration is also conceivable as a lens unit that improves the accuracy of the mounting position and posture of the lens group. For example, as shown in FIG. 6, a spacer 29 ′ is interposed between the first lens 20 ′ and the second lens 21 ′ to define the distance between the first lens 20 ′ and the second lens 21 ′. Further, it is possible to configure the lens unit 10 ′ that also defines the postures of the first lens 20 ′ and the second lens 21 ′ (for example, parallelization of the optical axis). However, the spacer 29 'is usually formed of a hard material such as metal or resin, and rattling may occur when the first lens 20' or the lens barrel 17 'contracts due to temperature change. On the other hand, since the lens unit of the present embodiment uses the elastic member 19, the first lens 20 is contracted even when the first lens 20 or the lens barrel 17 contracts due to a temperature change. The pressure on the 20 and the second lens 21 can be maintained. Therefore, according to the lens unit of the present embodiment, it is possible to suppress the occurrence of rattling with respect to temperature changes. Further, as described above, in the lens unit 10 ′, the surface of the first lens 20 ′ and the second lens 21 ′ can be damaged by using the spacer 29 ′ formed of a hard material. On the other hand, in the lens unit of the present embodiment, since the elastic member 19 can be formed using a material softer than the first lens 20 and the second lens 21, the first lens 20 and the second lens 21 It is possible to suppress damage to the surface. Further, in the lens unit 10 ′, an O-ring 30 ′ is provided separately from the spacer 29 ′ in order to waterproof the inside. On the other hand, in the lens unit of this embodiment, since the elastic member 19 also functions as the spacer 29 ′ and the O-ring 30 ′, the number of parts can be reduced and the manufacturing cost can be reduced.

  In the present embodiment, it is also conceivable to use an adhesive instead of the elastic member 19. However, compared with such a modification, the lens unit of the present embodiment has the following effects. That is, in the modified example, gas may be generated when the adhesive is cured, but in the lens unit of the present embodiment, no gas is generated and generation of fogging on the surface of the lens group 16 can be suppressed. In the modified example, the first lens and the second lens are easily separated from each other even with an impact, but in the lens unit of the present embodiment, the elastic member 19 is separated from the first lens 20 and the second lens 21. Less likely. Further, in the modification, the adhesive may be separated from the first lens and the second lens depending on the temperature change due to the influence of linear expansion, but in the lens unit of the present embodiment, the linear expansion coefficient of the elastic member 19 is Since it is lower than the adhesive, it has little effect on temperature changes. Further, in the modified example, dripping of the adhesive may occur at the time of mounting, but in the lens unit of the present embodiment, dripping does not occur at the time of mounting, and contamination of the first lens 20 and the second lens 21 can be suppressed. is there.

  Although the present invention has been described based on the drawings and embodiments, it should be noted that those skilled in the art can easily make various changes and modifications based on the present disclosure. Therefore, it should be noted that these variations and modifications are included in the scope of the present invention.

DESCRIPTION OF SYMBOLS 10, 10 'Lens unit 11 Imaging device 12 Moving body 13 Display apparatus 14 Imaging device 15 Output part 16 Lens group 17, 17' Lens barrel 18 Holding member 19 Elastic member 20, 20 '1st lens 20C Contact surface part 20L Lens effective Surface portion 21, 21 ′ Second lens 22 Housing portion 22C Contact surface portion 23 Pressing portion 24 First housing portion 25 Second housing portion 26 First portion 27 Thin portion 28 Second portion 29 ′ Spacer 30 ′ O-ring CX1, CX2 Center axis OX Optical axis

Claims (8)

A lens group including at least a first lens and a second lens;
It has a cylindrical shape and holds the lens group to be disposed from the object side along the central axis of the cylindrical in order of the first lens and the second lens inside the cylindrical mirror A tube,
A pressing member that fixes the lens group inside the lens barrel by pressing the first lens into the lens barrel;
An elastic member interposed between the first lens and the second lens ,
The elastic member is elastically deformed by the pressing of the first lens by the pressing member , and is interposed between the first part that presses the second lens, and the first part and the second lens. A lens unit comprising: a thin-walled portion that is thinner than a minimum value of the generated gap; and a second portion that is continuous with the first lens through the thin-walled portion . The lens unit according to claim 1,
The elastic member is in close contact with the inner surfaces of the first lens, the second lens, and the lens barrel during elastic deformation caused by pressing of the first lens. The lens unit according to claim 1 or 2,
The lens unit, wherein the first lens and the lens barrel have a structure in surface contact with each other by pressing from the pressing member. The lens unit according to any one of claims 1 to 3,
The lens unit, wherein the elastic member has a light shielding property. The lens unit according to claim 4,
The second site is characterized by being freed from the pressing of the previous SL first than said portion of the first lens the pressing member located on the optical axis side through the first lens Lens unit. An imaging apparatus comprising: the lens unit according to claim 1; and an imaging element that captures a subject image formed by the lens unit. The imaging apparatus according to claim 6,
An imaging apparatus, further comprising: an output unit that outputs an image signal generated by the imaging element by imaging the subject. It is a moving body which has an imaging device of Claim 6 or Claim 7, Comprising: The said imaging device is installed in the exterior of the said mobile body so that the periphery of the said mobile body can be imaged. Moving body.

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