JP2018105905A - Lens unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens unit in which a seal member can be easily provided between an object side lens and an inner peripheral surface of a lens barrel without an increase in the size of the lens unit.SOLUTION: An outer periphery of an object side lens 12 on an image side is provided with an inclined surface 12a so that it becomes closer to an object side as it proceeds toward the outside in a radial direction. A seal member 35 is provided to be attached firmly to the inclined surface 12a and an inner peripheral surface of a lens barrel 11, in a cavity part 34 having a triangular cross section that is provided between the inclined surface 12a and the inner peripheral surface. Therefore, unlike before, the outer periphery of the object side lens 12 on the image side is formed with a notch part, the notch part needs not to be provided with a seal member, and the diameter of the object side lens 12 needs not to be larger. Thus, the seal member can be easily provided between the object side lens 12 and the inner peripheral surface of the lens barrel 11 without an increase in the size of a lens unit.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a small lens unit provided in an in-vehicle camera mounted on a vehicle such as an automobile.

  In recent years, since a monitor is mounted on a car for car navigation or the like, for example, as a back monitor system, an image taken by a vehicle-mounted camera mounted on the back of the vehicle is displayed on the monitor. Also, a system has been developed in which this camera is provided not only in the back but also in the front, rear, left, and right sides of the vehicle, and an image overlooking the periphery of the vehicle is synthesized and displayed on a monitor in substantially real time.

In an in-vehicle camera that has a sensing function such as accurately and quickly recognizing images of obstacles and people, the lens unit uses a metal barrel such as stainless steel or aluminum alloy and a glass lens. Therefore, high reliability is realized (for example, see Patent Document 1).
In this lens unit, as a group of lenses in a cylindrical metal barrel, a plurality of glass lenses are arranged so as to overlap in the optical axis direction in a substantial barrel.

In such a lens unit, in order to prevent water and dust from entering from the opening on the object side of the lens barrel, a means such as an O-ring is provided as a means for ensuring airtightness in the lens barrel from the object side. A seal member is provided between the object side lens and the inner peripheral surface of the lens barrel.
For example, as shown in FIG. 3, a flange portion 1a is provided at the object-side end of the lens barrel 1, and the outer peripheral portion of the object-side lens 2 is brought into contact with the flange portion 1a. Are positioned in the optical axis direction.
Further, a cutout portion 3 having an L-shaped cross section is formed along the circumferential direction on the outer peripheral portion of the object side lens 2 on the object side, and is provided between the cutout portion 3 and the inner peripheral surface of the lens barrel 1. An O-ring 5 as a seal member is provided in a hollow portion having a rectangular cross section. In this state, the O-ring 5 is crushed in the radial direction of the lens barrel 1, the outer peripheral surface of the O-ring 5 is in close contact with the inner peripheral surface of the lens barrel 1, and the inner peripheral surface is the object-side lens 2. The cutout 3 is in close contact with the cylindrical surface 3a. Thereby, the airtightness in the lens barrel 1 from the object side is secured.

JP 2006-292927 A

However, in the conventional lens unit, the notch 3 is formed in the outer peripheral portion of the object side lens on the object side, and the O-ring 5 is provided in the notch 3, so the diameter of the object side lens needs to be increased. . This is because when the diameter of the object side lens is small, the notch 3 for inserting an O-ring having a predetermined size (width) is formed on the outer periphery of the object side lens. Since it exceeds the inner peripheral edge of the flange portion 1a, the outer peripheral portion of the object side lens 2 cannot be brought into contact with the flange portion 1a, and the object side lens 2 cannot be positioned in the optical axis direction. This is because a plurality of lenses cannot be accommodated inside the lens barrel.
Accordingly, since it is necessary to increase the diameter of the object side lens as described above in order to form a notch for providing an O-ring as a seal member, this hinders the lens unit from being downsized.

  The present invention has been made in view of the above circumstances, and includes a lens unit that can easily provide a seal member between the object side lens and the inner peripheral surface of the lens barrel without increasing the size of the lens unit. The purpose is to provide.

In order to solve the above problems, a lens unit of the present invention includes a plurality of lenses arranged along an optical axis, a metal barrel that houses the plurality of lenses, and the most of the plurality of lenses. A lens unit provided between an object side lens located on the object side and an inner peripheral surface of the lens barrel,
On the outer peripheral part of the image side of the object side lens, an inclined surface is provided so as to approach the object side as it goes radially outward,
The sealing member is provided in a state of being in close contact with the inclined surface and the inner peripheral surface in a hollow section having a triangular cross section provided between the inclined surface and the inner peripheral surface of the lens barrel. And

  The plurality of lenses may be made of glass.

In the present invention, a seal member is disposed between the inclined surface and the inclined surface provided in the outer peripheral portion on the image side of the object side lens and the hollow portion having a triangular cross section provided between the inner peripheral surface of the lens barrel and the inclined surface. Since it is provided in close contact with the inner peripheral surface, unlike the prior art, it is not necessary to form a notch in the outer peripheral portion of the object side lens on the object side and to provide a seal member in the notch. For this reason, since it is not necessary to increase the diameter of the object side lens, a seal member can be easily provided between the object side lens and the inner peripheral surface of the lens barrel without increasing the size of the lens unit.
Further, since the seal member is provided in close contact with the inclined surface and the inner peripheral surface, a reaction force acts on the seal member from the inclined surface and the inner peripheral surface. For this reason, even if the diameter of the cross section of the seal member is small, sufficient airtightness can be ensured, so that the lens unit can be reduced in size.

In the configuration of the present invention, a flat surface adjacent to the inclined surface is provided on the image side surface of the object side lens,
An annular spacer that contacts the inner peripheral surface of the lens barrel or a flange portion of another lens is in contact with this flat surface,
It is preferable that the seal member is in close contact with the spacer or the flange portion.

  According to such a configuration, since the sealing member provided in the hollow portion having a triangular cross section is in close contact with the spacer or the flange portion, it is possible to more reliably ensure the airtightness by the sealing member, and the sealing member. Can be prevented from shifting in the optical axis direction.

Further, in the above configuration of the present invention, a flange portion that protrudes radially inward of the lens barrel is provided at an object side end of the lens barrel,
An annular spacer located between the lenses adjacent in the optical axis direction is provided inside the lens barrel,
The plurality of lenses and the spacer are housed inside the lens barrel in a state of being in contact with each other in the optical axis direction,
The object side lens is brought into contact with the flange portion, and the lens or the spacer located closest to the image side is directed toward the flange portion side by a pressing member provided at an image side opening of the lens barrel. It may be pressed.

  According to such a configuration, the object side lens is brought into contact with the flange portion provided at the object side end of the lens barrel, and the lens or spacer positioned closest to the image side is located at the image side opening of the lens barrel. Since the pressing member is pressed toward the flange portion, the lens and the spacer can be reliably accommodated while positioning the lens and the spacer in the optical axis direction inside the lens barrel.

  According to the present invention, the seal member can be easily provided between the object side lens and the inner peripheral surface of the lens barrel without increasing the size of the lens unit.

It is a schematic sectional drawing which shows the lens unit which concerns on embodiment of this invention. It is a schematic sectional drawing which shows the lens of the lens unit of a reference example. It is a schematic sectional drawing which shows the principal part of the conventional lens unit.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The lens unit of the present embodiment is provided in an in-vehicle camera mounted on a vehicle such as an automobile.
As shown in FIG. 1, the lens unit 10 according to the present embodiment includes a cylindrical lens barrel 11 and a lens group including a plurality (five) of lenses 12 to 16 arranged in the lens barrel 11. 17.
An intermediate ring (spacer) 20 is provided between the lens 12 and the lens 13, an intermediate ring 21 is provided between the lens 13 and the lens 14, and an intermediate is provided between the lens 14 and the lens 16. An annulus 22 is provided.

  The plurality of lenses 12 to 16 that are fixedly supported by the lens barrel 11 are arranged in a state in which the optical axes thereof coincide with each other, and the respective lenses 12 to 16 are arranged along one optical axis. In this state, one lens group 17 used for imaging is configured. Accordingly, in the following description, when simply referred to as an optical axis, the optical axis of each of the lenses 12 to 16 and the optical axis of the lens group 17 are illustrated.

The lens barrel 11 is a cylindrical member that is open at both ends, has an opening 11a at the end (one end) on the object side (outside, incident side), and the end on the image side (inside, exit side). The other end portion has an opening 11b. Further, a reduced diameter portion 11c formed so as to narrow the opening 11a is provided at the object side end of the lens barrel 11, and an inner peripheral surface of the reduced diameter portion 11c has a shape that performs a diaphragm function. Is formed. The opening 11a is narrower than the opening 11b.
A female screw portion 11d is formed at the image side end of the lens barrel 11, and a male screw portion 25a formed on the outer peripheral surface of the pressing member 25 is screwed into the female screw portion 11d.
Further, a flange portion 30 protruding toward the inner peripheral side of the lens barrel 11 is provided at the object side end of the lens barrel 11, and an opening portion 11a and a reduced diameter portion 11c are provided on the inner peripheral side of the flange portion 30. Is provided.

Inside the lens barrel 11, a plurality (two) of cylindrical accommodating portions 31 a and 31 b having different diameters are provided. The accommodating portions 31a and 31b are continuously arranged, and the accommodating portion 31b has a larger diameter than the accommodating portion 31a.
And in the accommodating part 31a, the lens 12 and the lens 13 are accommodated in the state which contact | abutted those outer peripheral surfaces to the inner peripheral surface of the accommodating part 31a with a predetermined space | interval in the optical axis direction. Moreover, the intermediate ring 20 is accommodated in the accommodating part 31a in the state which contact | abutted the outer peripheral surface between the lenses 12 and 13 to the inner peripheral surface of the accommodating part 31a.
In the accommodating portion 31b, the lens 14 and the lens 16 are accommodated with a predetermined interval in the optical axis direction and with their outer peripheral surfaces in contact with the inner peripheral surface of the accommodating portion 31b.
Moreover, the intermediate ring 22 is accommodated in the accommodating part 31b in the state which contact | abutted the outer peripheral surface between the lenses 14 and 16 with the inner peripheral surface of the accommodating part 31b.
The lenses 14 and 15 are two bonded lenses, and the lens 15 is provided inside the upper portion of the intermediate ring 22.
In this way, the lenses 12 to 16 and the intermediate rings 20 to 22 are positioned in the radial direction.

The lens (object-side lens) 12 is a glass-polished lens, and an inclined surface 12a is provided along the circumferential direction on the outer periphery of the image side so as to approach the object side as it goes radially outward. The inclined surface 12a is inclined by about 45 ° with respect to the optical axis, but the inclination angle is not limited to 45 ° and is set as appropriate. Further, a flat surface 12b is provided in an annular shape on the lower surface (image side surface) of the lens 12 so as to be orthogonal to the optical axis, and the flat surface 12b is located on the optical axis side of the lens 12 with respect to the inclined surface 12a. In addition, it is provided adjacent to the inclined surface 12a.
The lens 12 is inserted from the opening 11b of the lens barrel 11, and the upper surface of the outer peripheral portion of the lens 12 is brought into contact with the lower surface of the flange portion 30 (image-side surface), thereby positioning in the optical axis direction. Has been made.

The intermediate ring 20 is formed in a disc annular shape, and the outer peripheral surface is in contact with the inner peripheral surface of the accommodating portion 31a. Further, the intermediate ring 20 is inserted from the opening 11b of the lens barrel 11, and then the upper surface is brought into contact with the flat surface 12b of the lens 12, thereby positioning in the optical axis direction.
Further, an O-ring (seal member) 35 is accommodated between the inclined surface 12 a of the lens 12, the inner peripheral surface of the accommodating portion 31 a (the inner peripheral surface of the lens barrel 11), and the upper surface of the intermediate ring 20. A cavity 34 having a triangular cross section is provided.

The lens 13 is a glass mold lens, and is inserted through the opening 11b of the lens barrel 11, and then the upper surface of the flange portion of the lens 13 is brought into contact with the lower surface of the intermediate ring 20 (image-side surface). Directional positioning has been made.
The intermediate ring 21 is formed in an annular shape, and the outer peripheral surface is in contact with the inner peripheral surface of the accommodating portion 31b. The intermediate ring 21 is inserted from the opening 11 b of the lens barrel 11, and the upper surface is brought into contact with the lower surface (image-side surface) of the flange portion of the lens 13 via a disc-shaped annular diaphragm member 26. Thus, positioning in the optical axis direction is performed.

The lens 14 is a glass polishing lens, and is inserted through the opening 11b of the lens barrel 11, and then the upper surface of the flange portion of the lens 14 is brought into contact with the lower surface of the intermediate ring 21 (image-side surface), whereby the optical axis. Directional positioning has been made.
The lens 15 is a glass polishing lens and is bonded to the lens 14 as described above.
The intermediate ring 22 is formed in a cylindrical shape, and the outer peripheral surface is in contact with the inner peripheral surface of the accommodating portion 31b. Further, the intermediate ring 22 is inserted from the opening 11b of the lens barrel 11, and then the upper end surface is brought into contact with the lower surface (image side surface) of the flange portion of the lens 14, thereby positioning in the optical axis direction. ing. Further, on the inner peripheral surface of the intermediate ring 22, a protrusion 22 a having a triangular cross section is formed along the circumferential direction slightly above (on the object side) the substantially central portion in the axial direction. The tip edge of the protrusion 22a is in contact with the outer peripheral portion of the lens surface of the lens 15, thereby having a diaphragm function.

  The lens 16 is a glass-polished lens, and is inserted into the lens barrel 11 through the opening 11b, and then the upper surface of the flange portion of the lens 16 is brought into contact with the lower end surface (image-side surface) of the intermediate ring 22, thereby Axial positioning is performed.

An optical filter (infrared cut filter) 27 is accommodated in the lower end portion of the accommodating portion 31b. The optical filter 27 is inserted from the opening portion 11b of the lens barrel 11, and the outer peripheral portion of the upper surface of the lens 16 is arranged on the upper surface. Positioning in the optical axis direction is made by contacting the lower surface (image side surface) of the flange portion through a disc-shaped annular diaphragm member 28.
Further, the holding member 25 screwed into the male screw portion 11d at the image side end of the lens barrel 11 is tightened with a constant torque, so that the optical filter 27 is attached to the flange portion 30 side of the lens barrel 11 (FIG. 1). In FIG. Accordingly, the optical filter 27, the diaphragm member 28, the lens 16, the intermediate ring 22, the lens 14, the intermediate ring 21, the diaphragm member 26, the lens 13, the intermediate ring 20, and the lens 12 are pressed upward, and the lens 12 is flanged. Positioning in the optical axis direction is performed by being pressed against 30.

  As described above, the hollow portion 34 having a triangular cross section is formed between the inclined surface 12 a of the lens 12, the inner peripheral surface of the accommodating portion 31 a (the inner peripheral surface of the lens barrel 11), and the upper surface of the intermediate ring 20. An O-ring (seal member) 35 is accommodated in the cavity 34. The O ring 35 is accommodated in the cavity 34 in a state of being crushed in the radial direction and the optical axis direction by the inclined surface 12a, the inner peripheral surface of the accommodating portion 31a, and the upper surface of the intermediate ring 20, and in this state The O-ring 35 is in close contact with the inclined surface 12a, the inner peripheral surface of the accommodating portion 31a, and the upper surface of the intermediate ring 20.

In order to incorporate the O-ring 35 into the lens barrel 11, for example, before inserting the object-side lens 12 into the lens-barrel 11, the O-ring 35 is fitted into the annular inclined surface 12 a of the object-side lens 12. The inner peripheral surface of the ring 35 is pressed against the inclined surface 12a.
Then, the object side lens 12 with the O-ring is inserted from the opening 11b of the lens barrel 11, the outer peripheral portion of the upper surface of the object side lens 12 is brought into contact with the flange portion 30, and the outer peripheral surface of the O ring 35 is mirrored. It contacts the inner peripheral surface of the cylinder 1 (the inner peripheral surface of the accommodating portion 31a).

  Next, the intermediate ring 20, the lens 13, the diaphragm member 26, the intermediate ring 21, the lenses 14 and 15, the intermediate ring 22, the lens 16, the diaphragm member 28 and the optical filter 27 are arranged in this order from the opening 11 b of the lens barrel 11. insert. As a result, a hollow portion 34 having a triangular cross section is provided between the inclined surface 12a of the lens 12, the inner peripheral surface of the housing portion 31a (the inner peripheral surface of the lens barrel 11), and the upper surface of the intermediate ring 20. The O-ring 35 is accommodated in the cavity 34.

Next, the pressing member 25 is inserted from the opening portion 11b, and is screwed and tightened to the female screw portion 11d at the lower end portion of the barrel 11 of the male screw portion 25a of the pressing member 25.
Accordingly, the optical filter 27, the diaphragm member 28, the lens 16, the intermediate ring 22, the lens 14, the intermediate ring 21, the diaphragm member 26, the lens 13, the intermediate ring 20, and the lens 12 are pressed upward, and the lens 12 is flanged. 30.
Then, the O-ring 35 accommodated in the cavity 34 is crushed in the radial direction and the optical axis direction by the inclined surface 12a, the inner peripheral surface of the accommodating portion 31a, and the upper surface of the intermediate ring 20, and the O-ring 35 Is in close contact with the inclined surface 12a, the inner peripheral surface of the accommodating portion 31a, and the upper surface of the intermediate ring 20. Thereby, airtightness in the lens barrel 11 from the object side is ensured, and intrusion of water and dust into the lens barrel 11 is prevented.

As described above, according to the present embodiment, it is provided between the inclined surface 12 a provided on the image side outer peripheral portion of the object side lens 12, the inner peripheral surface of the lens barrel 11, and the upper surface of the intermediate ring 20. Since the O-ring (seal member) 35 is provided in a state where the O-ring (seal member) 35 is in close contact with the inclined surface 12a, the inner peripheral surface of the lens barrel 1 and the upper surface of the intermediate ring 20 It is not necessary to form a notch in the outer peripheral portion of the side lens 12 on the object side and to provide a seal member in this notch. For this reason, since it is not necessary to increase the diameter of the object side lens 12, an O-ring (seal member) 35 is provided between the object side lens 12 and the inner peripheral surface of the barrel 1 without increasing the size of the lens unit. It can be easily provided.
Further, since the O ring (seal member) 35 is provided in close contact with the inclined surface 12a, the inner peripheral surface of the lens barrel 11 and the upper surface of the intermediate ring 20, the inclined surface 12a and the lens barrel 11 are provided on the O ring 35. A reaction force acts from the inner peripheral surface of the intermediate ring 20 and the upper surface of the intermediate ring 20. For this reason, even if the diameter of the cross section of the O-ring 35 is small, sufficient airtightness can be ensured, so that the lens unit can be downsized.

Further, the upper surface of the intermediate ring 20 that contacts the inner peripheral surface of the lens barrel 11 is brought into contact with the image-side flat surface 12 b of the object side lens 12, and the O-ring 35 is in close contact with the upper surface of the intermediate ring 20. Therefore, the airtightness by the O-ring 35 can be ensured more reliably, and the deviation of the O-ring 35 in the optical axis direction can be prevented.
Further, the object side lens 12 is brought into contact with a flange portion 30 provided at the end of the lens barrel 11 on the object side, and the lens 16 positioned closest to the image side is positioned on the image side of the lens barrel 11 via the optical filter 27. The lens 12 to 16, the intermediate rings 20 to 22, the diaphragm members 26 and 28, and the optical filter 27 are placed inside the lens barrel 11 because it is pressed toward the flange by the presser member 25 provided in the opening. It is possible to securely store them while positioning them in the optical axis direction.

(Reference example)
Next, a reference example in which an O-ring (seal member) can be easily provided between the object side lens and the inner surface of the lens barrel without increasing the size of the lens unit will be described.
The lens unit of this example is provided in a vehicle-mounted camera mounted on a vehicle such as an automobile.

  Further, the lens unit of this example is different from the lens unit of the above-described embodiment in that a sheet member is inserted between the object side lens 12 and the flange portion 30, and an O-ring 35 as in the embodiment is provided. Since this is not the case, this point will be described below, and the same reference numerals are given to common portions with the embodiment, and the description will be omitted or simplified.

As shown in FIG. 2, in the lens unit 40 of this example, between the flat surface 12 c outside the effective diameter of the object side lens surface of the object side lens 12 and the lower surface (image side surface) of the flange portion 30. A sheet member 41 made of silicon rubber is inserted.
The sheet member 41 is formed in an annular shape with a thickness of about 100 μm to 200 μm. Further, the outer peripheral edge of the sheet member 41 is in contact with the inner peripheral surface of the lens barrel 11, and the inner peripheral edge is located on the radially outer side from the inner peripheral edge of the flange portion 30.
In this example, unlike the embodiment, the object-side lens 12 is not provided with the inclined surface 12a, and accordingly, the flat surface 12b extends to the outer diameter side from the embodiment.

In order to insert such a sheet member 41 between the object side lens 12 and the flange portion 30, first, the sheet member 41 is opened to the opening of the lens barrel 11 before the object side lens 12 is inserted into the lens barrel 11. It is inserted from the portion 11b and is in contact with the lower surface (image side surface) of the flange portion 30.
Next, the object side lens 12, the intermediate ring 20, the lens 13, the diaphragm member 26, the intermediate ring 21, the lenses 14 and 15, the intermediate ring 22, the lens 16, the diaphragm member 28, and the optical filter 27 are arranged in this order in the lens barrel 11. It inserts from the opening part 11b.
Next, the pressing member 25 is inserted from the opening portion 11b, and is screwed and tightened to the female screw portion 11d at the lower end portion of the barrel 11 of the male screw portion 25a of the pressing member 25.
As a result, the optical filter 27, the diaphragm member 28, the lens 16, the intermediate ring 22, the lens 14, the intermediate ring 21, the diaphragm member 26, the lens 13, the intermediate ring 20, the lens 12 and the sheet member 41 are pressed upward, and the sheet The member 41 is in pressure contact with the lower surface of the flange portion 30 and the flat surface 12 c of the lens 12.
Then, when the pressing member 25 is screwed in until the thickness of the sheet member 41 reaches, for example, about 70 μm, the sheet member 41 comes into close contact with the lower surface of the flange portion 30 and the flat surface 12 c of the lens 12. Thereby, airtightness in the lens barrel 11 from the object side is ensured, and intrusion of water and dust into the lens barrel 11 is prevented.

  According to this example, since the sheet member 41 inserted between the object side lens 12 and the flange portion 30 is in close contact with the lower surface of the flange portion 30 and the flat surface 12c of the lens 12, It is not necessary to form a notch in the outer peripheral portion of the side lens 12 on the object side and to provide a seal member in this notch. For this reason, since it is not necessary to increase the diameter of the object side lens 12, a sheet member (seal member) 41 can be easily provided between the object side lens 12 and the inner surface of the barrel 1 without increasing the size of the lens unit. Can be provided.

DESCRIPTION OF SYMBOLS 10 Lens unit 11 Lens barrel 12-16 Lens 12 Object side lens 12a Inclined surface 12b Flat surface 20-22 Intermediate ring (spacer)
25 Presser member 30 Flange part 34 Cavity part 35 O-ring (seal member)

Claims (4)

A plurality of lenses arranged along the optical axis, a metal lens barrel in which the plurality of lenses are accommodated, an object side lens located closest to the object side among the plurality of lenses, and an inner periphery of the lens barrel A lens unit provided between the surface and a seal member,
On the outer peripheral part of the image side of the object side lens, an inclined surface is provided so as to approach the object side as it goes radially outward,
The sealing member is provided in a state of being in close contact with the inclined surface and the inner peripheral surface in a hollow section having a triangular cross section provided between the inclined surface and the inner peripheral surface of the lens barrel. Lens unit. A flat surface adjacent to the inclined surface is provided on the image side surface of the object side lens,
An annular spacer that contacts the inner peripheral surface of the lens barrel or a flange portion of another lens is in contact with this flat surface,
The lens unit according to claim 1, wherein the seal member is in close contact with the spacer or the flange portion. On the object side end of the lens barrel, a flange portion protruding inward in the radial direction of the lens barrel is provided,
An annular spacer located between the lenses adjacent in the optical axis direction is provided inside the lens barrel,
The plurality of lenses and the spacer are housed inside the lens barrel in a state of being in contact with each other in the optical axis direction,
The object side lens is brought into contact with the flange portion, and the lens or the spacer located closest to the image side is directed toward the flange portion side by a pressing member provided at an image side opening of the lens barrel. The lens unit according to claim 1, wherein the lens unit is pressed.   The lens unit according to claim 1, wherein the plurality of lenses are made of glass.

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