JP7094346B2 - Lens unit - Google Patents

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 a car navigation system or the like, for example, as a back monitor system, an image taken by an in-vehicle camera mounted on the back of the vehicle is displayed on the monitor. In addition, a system has been developed in which this camera is installed not only on the back but also on the front, back, left and right of the vehicle, and an image that allows the surroundings of the vehicle to be seen is synthesized in substantially real time and displayed on the monitor.

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

Further, in such a lens unit, in order to prevent water, dust, etc. from entering through the opening of the lens barrel on the object side, an О ring or the like is used as a means for ensuring the airtightness inside the lens barrel from the object side. A sealing member is provided between the lens on the object side and the inner peripheral surface of the lens barrel.
For example, as shown in FIG. 3, a flange portion 1a is provided at the end portion of the lens barrel 1 on the object side, and the outer peripheral portion of the object side lens 2 is brought into contact with the flange portion 1a, whereby the object side lens 2 is provided. Is positioned in the optical axis direction.
Further, a notch 3 having an L-shaped cross section is formed on the outer peripheral portion of the object-side lens 2 on the object side along the circumferential direction, and is provided between the notch 3 and the inner peripheral surface of the lens barrel 1. An O-ring 5 as a sealing member is provided in a cavity 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. It is in close contact with the cylindrical surface 3a of the notch 3. As a result, the airtightness inside the lens barrel 1 from the object side is ensured.

Japanese Unexamined Patent Publication No. 2006-292927

However, in the conventional lens unit, the notch 3 is formed on the outer peripheral portion of the object side lens on the object side, and the O-ring 5 is provided in the notch portion 3, so that it is necessary to increase the diameter of the object side lens. .. This is because when the diameter of the object-side lens is small, if a notch 3 for inserting an O-ring having a predetermined size (width) is formed on the outer peripheral portion of the object-side lens, the width of the notch 3 becomes the width of the lens barrel 1. Since the inner peripheral edge portion of the flange portion 1a is exceeded, 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 and the like cannot be stored inside the lens barrel.
Therefore, it is necessary to increase the diameter of the lens on the object side as described above in order to form the notch for providing the О ring as the sealing member, which hinders the miniaturization of the lens unit.

The present invention has been made in view of the above circumstances, and a lens unit capable of easily providing a sealing member between an object-side lens and an inner peripheral surface of a lens barrel without increasing the size of the lens unit. The purpose is to provide.

In order to solve the above-mentioned problems, the lens unit of the present invention includes a plurality of lenses arranged along an optical axis, a metal lens barrel in which the plurality of lenses are housed, and the most of the plurality of lenses. A lens unit including a sealing member provided between an object-side lens located on the object-side and an inner peripheral surface of the lens barrel.
An inclined surface is provided on the outer peripheral portion of the image side of the object-side lens so as to approach the object side toward the outside in the radial direction.
It is characterized in that the sealing member is provided in a state of being in close contact with the inclined surface and the inner peripheral surface in a cavity having a triangular cross section provided between the inclined surface and the inner peripheral surface of the lens barrel. And.

Further, the plurality of lenses may be made of glass.

In the present invention, a sealing member is provided in the inclined surface and the said Since it is provided in close contact with the inner peripheral surface, it is not necessary to form a notch on the outer peripheral portion of the object-side lens on the object side and to provide a sealing member in this notch, unlike the conventional case. Therefore, since it is not necessary to increase the diameter of the object-side lens, a sealing 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 sealed member from the inclined surface and the inner peripheral surface. Therefore, 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 miniaturized.

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 or a flange portion of another lens that abuts on the inner peripheral surface of the lens barrel is abutted against this flat surface.
It is preferable that the sealing 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, the airtightness of the sealing member can be more reliably ensured and the sealing member can be secured. Can be prevented from shifting in the optical axis direction.

Further, in the above-mentioned configuration of the present invention, a flange portion is provided at the end portion of the lens barrel on the object side so as to project inward in the radial direction of the lens barrel.
An annular spacer located between the lenses adjacent to each other 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 abutted against 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 in the image-side opening of the lens barrel. It may be pressed.

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

According to the present invention, a sealing member can be easily provided between the lens on the object side 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 cross-sectional view which shows the lens of the lens unit of a reference example. It is a schematic cross-sectional view which shows the main 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.
Further, as shown in FIG. 1, the lens unit 10 of the present embodiment is a lens group including a cylindrical lens barrel 11 and a plurality of (five) lenses 12 to 16 arranged in the lens barrel 11. It is equipped with 17.
Further, 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 ring 21 is provided between the lens 14 and the lens 16. A ring 22 is provided.

The plurality of lenses 12 to 16 fixed and supported by the lens barrel 11 are arranged in a state where their respective optical axes are aligned, and the respective lenses 12 to 16 are arranged along one optical axis. In the state, it constitutes a group of lenses 17 used for imaging. Therefore, when the term "optical axis" is simply used below, the optical axis of each lens 12 to 16 is shown and the optical axis of the lens group 17 is shown.

The lens barrel 11 is a cylindrical member having openings at both ends, has an opening 11a at an end (one end) on the object side (outside, incident side), and has an end on the image side (inside, emission side). It has an opening 11b at (the other end). Further, a reduced diameter portion 11c formed so as to narrow the opening 11a is provided at the end portion of the lens barrel 11 on the object side, and the inner peripheral surface of the reduced diameter portion 11c has a shape that fulfills a diaphragm function. It is formed. The opening 11a is narrower than the opening 11b.
Further, a female screw portion 11d is formed at the end of the lens barrel 11 on the image side, and a male screw portion 25a formed on the outer peripheral surface of the presser member 25 is screwed into the female screw portion 11d.
Further, a flange portion 30 projecting to the inner peripheral side of the lens barrel 11 is provided at the end portion of the lens barrel 11 on the object side, 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 of (two) cylindrical accommodating portions 31a and 31b 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.
The lens 12 and the lens 13 are housed in the accommodating portion 31a at predetermined intervals in the optical axis direction, with their outer peripheral surfaces in contact with the inner peripheral surface of the accommodating portion 31a. Further, in the accommodating portion 31a, the intermediate ring 20 is accommodated between the lenses 12 and 13 in a state where the outer peripheral surface thereof is in contact with the inner peripheral surface of the accommodating portion 31a.
The lens 14 and the lens 16 are housed in the accommodating portion 31b at predetermined intervals in the optical axis direction and with their outer peripheral surfaces in contact with the inner peripheral surface of the accommodating portion 31b.
Further, in the accommodating portion 31b, the intermediate ring 22 is accommodated between the lenses 14 and 16 in a state where the outer peripheral surface thereof is in contact with the inner peripheral surface of the accommodating portion 31b.
The lenses 14 and 15 are two laminated lenses, and the lens 15 is provided inside the upper part of the intermediate ring 22.
In this way, the Rens 12 to 16 and the intermediate rings 20 to 22 are radially positioned.

The lens (object side lens) 12 is a glass polishing lens, and an inclined surface 12a is provided along the circumferential direction on the outer peripheral portion on the image side so as to approach the object side toward the outer side in the radial direction. 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 appropriately set. Further, a flat surface 12b is provided on the lower surface (the surface on the image side) of the lens 12 in an annular shape perpendicular 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. At the same time, it is provided adjacent to the inclined surface 12a.
Further, the lens 12 is inserted through the opening 11b of the lens barrel 11, and then the upper surface of the outer peripheral portion of the lens 12 is brought into contact with the lower surface (the surface on the image side) of the flange portion 30, so that positioning in the optical axis direction can be performed. It has been done.

The intermediate ring 20 is formed in a disk ring 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 positioned in the optical axis direction by being inserted through the opening 11b of the lens barrel 11 and then abutting the upper surface on the flat surface 12b of the lens 12.
Further, for accommodating the O-ring (seal member) 35 between the inclined surface 12a of the lens 12, the inner peripheral surface of the accommodating portion 31a (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 molded lens, and is inserted through the opening 11b of the lens barrel 11 and then abuts the upper surface of the flange portion of the lens 13 on the lower surface (the surface on the image side) of the intermediate ring 20 to bring the optical axis. The direction is positioned.
The intermediate ring 21 is formed in a disk ring shape, and the outer peripheral surface is in contact with the inner peripheral surface of the accommodating portion 31b. Further, the intermediate ring 21 is inserted from the opening 11b of the lens barrel 11 and then the upper surface thereof abuts on the lower surface (image side surface) of the flange portion of the lens 13 via the disc annular diaphragm member 26. Is positioned in the optical axis direction.

The lens 14 is a glass polishing lens, and is inserted through the opening 11b of the lens barrel 11 and then abuts the upper surface of the flange portion of the lens 14 on the lower surface (the surface on the image side) of the intermediate ring 21 to bring the optical axis. The direction is positioned.
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 positioned in the optical axis direction by being inserted from the opening 11b of the lens barrel 11 and then abutting the upper end surface on the lower surface (image side surface) of the flange portion of the lens 14. ing. Further, on the inner peripheral surface of the intermediate ring 22, a protrusion 22a having a triangular cross section is formed along the circumferential direction slightly above (object side) from 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 polishing lens, and is inserted through the opening 11b of the lens barrel 11 and then abuts the upper surface of the flange portion of the lens 16 on the lower end surface (image side surface) of the intermediate ring 22 to obtain light. Axial positioning is done.

An optical filter (infrared cut filter) 27 is housed in the lower end of the housing portion 31b, and the optical filter 27 is inserted through the opening 11b of the lens barrel 11 and the outer peripheral portion of the upper surface of the lens 16 is inserted. Positioning in the optical axis direction is performed by abutting the lower surface (the surface on the image side) of the flange portion via the disc annular diaphragm member 28.
Further, the pressing member 25 screwed to the male screw portion 11d at the end of the lens barrel 11 on the image side is tightened with a constant torque to shift the optical filter 27 to the flange portion 30 side of the lens barrel 11 (FIG. 1). Is pressed to the upper side). As a result, the optical filter 27, the aperture member 28, the lens 16, the intermediate ring 22, the lens 14, the intermediate ring 21, the aperture member 26, the lens 13, the intermediate ring 20 and the lens 12 are pressed upward, and the lens 12 has a flange portion. By being pressure-welded to 30, positioning in the optical axis direction is performed.

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

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 12a of the object-side lens 12, and the O-ring 35 is fitted into the lens barrel 11. The inner peripheral surface of the ring 35 is brought into pressure contact with the inclined surface 12a.
Then, the object-side lens 12 with the O-ring is inserted through the opening 11b of the lens barrel 11, the outer peripheral portion of the upper surface of the object-side lens 12 abuts on the flange portion 30, and the outer peripheral surface of the О ring 35 is mirrored. It abuts on the inner peripheral surface of the cylinder 1 (inner peripheral surface of the accommodating portion 31a).

Next, the intermediate ring 20, the lens 13, the aperture member 26, the intermediate ring 21, the lenses 14, 15, the intermediate ring 22, the lens 16, the aperture member 28, and the optical filter 27 are placed in this order from the opening 11b 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 accommodating portion 31a (inner peripheral surface of the lens barrel 11), and the upper surface of the intermediate ring 20. , The О ring 35 is housed in this cavity 34.

Next, the pressing member 25 is inserted through the opening 11b, screwed into the female threaded portion 11d at the lower end of the lens barrel 11 of the male threaded portion 25a of the pressing member 25, and tightened.
As a result, the optical filter 27, the aperture member 28, the lens 16, the intermediate ring 22, the lens 14, the intermediate ring 21, the aperture member 26, the lens 13, the intermediate ring 20 and the lens 12 are pressed upward, and the lens 12 has a flange portion. Press contact with 30.
Then, the O-ring 35 housed 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 housing part 31a, and the upper surface of the intermediate ring 20, and the O-ring 35 is crushed. 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. As a result, the airtightness inside the lens barrel 11 from the object side is ensured, and water and dust are prevented from entering the lens barrel 11.

As described above, according to the present embodiment, the inclined surface 12a provided on the outer peripheral portion of the object side lens 12 on the image side, the inner peripheral surface of the lens barrel 11, and the upper surface of the intermediate ring 20 are provided. Since the О ring (sealing member) 35 is provided in the hollow portion 34 having a triangular cross section 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, the object is different from the conventional one. It is not necessary to form a notch on the outer peripheral portion of the side lens 12 on the object side and to provide a sealing member in this notch. Therefore, since it is not necessary to increase the diameter of the object-side lens 12, an О ring (seal member) 35 is provided between the object-side lens 12 and the inner peripheral surface of the lens barrel 1 without increasing the size of the lens unit. It can be easily provided.
Further, since the О 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 О ring 35. A reaction force acts from the inner peripheral surface of the mirror and the upper surface of the intermediate ring 20. Therefore, even if the diameter of the cross section of the О ring 35 is small, sufficient airtightness can be ensured, so that the lens unit can be miniaturized.

Further, the upper surface of the intermediate ring 20 that abuts on the inner peripheral surface of the lens barrel 11 is in contact with the flat surface 12b on the image side of the object-side lens 12, and the О ring 35 is in close contact with the upper surface of the intermediate ring 20. Therefore, the airtightness of the О ring 35 can be ensured more reliably, and the О ring 35 can be prevented from being displaced in the optical axis direction.
Further, the object-side lens 12 is in contact with the flange portion 30 provided at the end of the lens barrel 11 on the object side, and the lens 16 located closest to the image side is on the image side of the lens barrel 11 via the optical filter 27. Since the pressing member 25 provided in the opening is pressed toward the flange portion, the lenses 12 to 16, the intermediate rings 20 to 22, the aperture members 26 and 28, and the optical filter 27 are placed inside the lens barrel 11. It can be securely stored 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 lens on the object side 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 an in-vehicle camera mounted on a vehicle such as an automobile.

Further, the difference between the lens unit of this example and the lens unit of the above-described embodiment is that a sheet member is inserted between the object-side lens 12 and the flange portion 30, and the О 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 will be given to the parts common to the embodiments, 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 12c outside the effective diameter of the lens surface on the object side of the lens 12 on the object side and the lower surface (plane on the image side) of the flange portion 30. A sheet member 41 made of silicon rubber is inserted into the lens.
The sheet member 41 is formed in an annular shape of a disk, and its thickness is set to 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 radially outside 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, so that 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, before inserting the object-side lens 12 into the lens barrel 11, the sheet member 41 is opened in the lens barrel 11. It is inserted from the portion 11b and is in contact with the lower surface (the surface on the image side) of the flange portion 30.
Next, the object-side lens 12, the intermediate ring 20, the lens 13, the aperture member 26, the intermediate ring 21, the lenses 14, 15, the intermediate ring 22, the lens 16, the aperture member 28, and the optical filter 27 are attached to the lens barrel 11 in this order. It is inserted through the opening 11b of.
Next, the pressing member 25 is inserted through the opening 11b, screwed into the female threaded portion 11d at the lower end of the lens barrel 11 of the male threaded portion 25a of the pressing member 25, and tightened.
As a result, the optical filter 27, the aperture member 28, the lens 16, the intermediate ring 22, the lens 14, the intermediate ring 21, the aperture member 26, the lens 13, the intermediate ring 20, the lens 12 and the sheet member 41 are pressed upward and the sheet is pressed. The member 41 is in pressure contact with the lower surface of the flange portion 30 and the flat surface 12c of the lens 12.
Then, when the pressing member 25 is screwed into the sheet member 41 until the thickness thereof becomes, 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 12c of the lens 12. As a result, the airtightness inside the lens barrel 11 from the object side is ensured, and water and dust are prevented from entering the lens barrel 11.

According to this example, 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, so that the object is different from the conventional one. It is not necessary to form a notch on the outer peripheral portion of the side lens 12 on the object side and to provide a sealing member in this notch. Therefore, since it is not necessary to increase the diameter of the object-side lens 12, the sheet member (seal member) 41 can be easily inserted between the object-side lens 12 and the inner surface of the lens barrel 1 without increasing the size of the lens unit. Can be provided.

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

Claims (5)

It is equipped with a plurality of lenses arranged along the optical axis and a lens barrel in which these multiple lenses are housed from the image side.
A flange portion is provided at the end of the lens barrel on the object side so as to project inward in the radial direction of the lens barrel.
A flat surface is provided on the object side of the outer peripheral portion of the first lens located on the object side of the plurality of lenses.
The plurality of lenses are housed inside the lens barrel in a state of being in contact with each other in the optical axis direction or in a state of being in contact with each other via a spacer.
The lens or the spacer located closest to the image side is a lens unit that is pressed toward the flange portion side by a pressing member screwed onto the inner peripheral surface of the opening on the image side of the lens barrel. hand,
A sheet-shaped sealing member is provided only between the image-side surface of the flange portion and the flat surface of the first lens.
The sealing member is in close contact with the flat surface of the first lens and the image-side surface of the flange portion in a compressed state.
A lens unit characterized in that the thickness of the sealing member is set to 100 μm to 200 μm. The lens unit according to claim 1, wherein the sheet-shaped sealing member is made of silicon rubber. Claim 1 is characterized in that the outer peripheral edge of the sheet-shaped sealing member is in contact with the inner peripheral surface of the lens barrel, and the inner peripheral edge thereof is located radially outside the inner peripheral edge of the flange portion. Or the lens unit according to 2. The lens unit according to any one of claims 1 to 3, wherein the plurality of lenses are made of glass. An in-vehicle camera comprising the lens unit according to any one of claims 1 to 4.

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