JP2012215711A - Lens unit, lens, and imaging unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens unit, a lens, and an imaging unit which can ensure waterproofing.SOLUTION: A lens unit includes plural lenses and a lens barrel that houses the plural lenses so that their optical axes are aligned with each other, in which the plural lenses respectively include a lens part and an edge part spreading around the lens part, the edge part of at least one lens of the plural lenses abuts on the inner peripheral surface of the lens barrel, a waterproofing film is formed between the inner peripheral surface of the lens barrel and the outer peripheral surface of the edge part abutting on the inner peripheral surface, and the waterproofing film is molded, by multi-color molding, all over the circumference of the inner peripheral surface of the lens barrel or the outer peripheral surface of the edge part of the lens and is pressed, sandwiched between the lens barrel and the lens.

Description

  The present invention relates to a lens unit, a lens, and an imaging unit.

  Currently, in-vehicle cameras used for back monitoring and front monitoring are widespread.

  An imaging unit used for an in-vehicle camera generally includes an imaging element such as a CCD (Charge Coupled Device) image sensor or a CMOS (Complementary metal-Oxide Semiconductor) image sensor, and a lens unit that forms an image on a light receiving surface of the imaging element. Prepare.

  The lens unit includes a plurality of lenses and a lens barrel that houses these lenses. As an imaging unit provided with such a lens unit, there exists a thing shown in patent document 1, for example. In the lens unit used in the imaging unit, water may enter from the outside into a gap where the lens and the lens barrel are fitted to each other. Therefore, as shown in Patent Document 1, it is necessary to provide a waterproof mechanism.

  The imaging device described in Patent Document 1 includes a lens barrel that holds a lens group, and an O-ring for waterproofing is provided between a pressing member fixed to the lens barrel and the first lens on the subject side. The provided configuration is described.

JP 2004-295119 A

  However, in the case of a configuration in which the lens and the O-ring are fitted into the lens barrel, the fitting work is complicated, and the mistake of forgetting to fit the O-ring or the incorrect fitting of the O-ring causes twist in the posture of the O-ring. Therefore, there is a concern that waterproofness is impaired.

  The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a lens unit, a lens, and an imaging unit that can be reliably waterproofed.

(1) a plurality of lenses;
A lens unit that houses the plurality of lenses so that their optical axes coincide with each other,
Each of the plurality of lenses has a lens part and an edge part extending around the lens part,
The edge portion of at least one of the plurality of lenses is in contact with the inner peripheral surface of the lens barrel, and the inner peripheral surface of the lens barrel and the outer peripheral surface of the edge portion in contact with the inner peripheral surface; A waterproof membrane is formed between
The waterproof film is formed by multicolor molding over the entire circumference of the inner peripheral surface of the lens barrel or the outer peripheral surface of the edge portion of the lens, and is a lens unit that is pressed between the lens barrel and the lens. .
(2) An imaging unit comprising: a sensor unit having an imaging element; and a lens unit that forms an image on the imaging element,
The lens unit is an imaging unit that is the lens unit according to (1).
(3) A lens housed in a cylindrical barrel,
The lens part,
An edge portion extending around the lens portion;
A waterproof film is formed on the outer peripheral surface of the lens edge, which is fitted to the inner peripheral surface of the lens barrel.
The waterproof film is a lens formed by multicolor molding over the entire circumference of the outer peripheral surface of the edge portion.

  According to the present invention, it is possible to provide a lens unit, a lens, and an imaging unit that can be reliably waterproofed.

The figure which shows an example of a structure of the lens unit of this invention The figure which shows the imaging unit provided with the lens unit shown in FIG. Sectional view of the lens barrel of the lens unit of FIG. Schematic cross-sectional view explaining the crushing rate and crushing amount of the waterproof membrane Schematic cross-sectional view showing a modification of the lens unit and the lens

FIG. 1 shows an example of the configuration of the lens unit.
The lens unit 10 includes an optical system 4 including a plurality of lenses and a lens barrel 1 that houses the optical system 4. In the illustrated example, the optical system 4 includes a first lens 11, a second lens 21, a third lens 31, and a fourth lens 41 that are arranged in order from the incident side (upper side in the drawing). .

  Note that the configuration of the optical system 4 is not limited to the illustrated example. For example, the number of lenses may be three or five or more.

  The lens barrel 1 includes a cylindrical tube portion 1a and a bottom portion 1b provided at one end of the tube portion 1a in the axial direction. Further, the end of the tube portion 1a of the barrel 1 opposite to the bottom portion 1b in the axial direction is open.

  The lens barrel 1 is provided with a stepped portion 7 on the inner peripheral surface of the tube portion 1a. The step portion 7 is provided in an annular shape around the central axis of the cylindrical portion 1a.

  The optical system 4 is disposed in the tube portion 1a in a state where the optical axis thereof coincides with the central axis of the tube portion 1a of the lens barrel 1. An opening 3 is provided at the center of the bottom 1b through which the optical axis of the optical system 4 passes. The light transmitted through the optical system 4 passes through the opening 3 and enters an image sensor of a sensor unit described later.

  The first lens 11, the second lens 21, the third lens 31, and the fourth lens 41 are arranged in this order from the end opposite to the bottom 1b of the lens barrel 1 in this order.

The first lens 11 is composed of a lens portion 12 having optical surfaces on the front and back sides and an edge portion 13 extending around the lens portion 12.
Similarly, the second lens 21 includes a lens part 22 having optical surfaces on the front and back sides and an edge part 23 extending around the lens part 22.
Similarly, the third lens 31 includes a lens part 32 having optical surfaces on the front and back sides and an edge part 33 that spreads around the lens part 32 in a bowl shape.
Similarly, the fourth lens 41 includes a lens part 42 having optical surfaces on the front and back sides, and an edge part 43 that spreads around the lens part 42 in a bowl shape.

  The first lens 11, the second lens 21, the third lens 31, and the fourth lens 41 are respectively fitted on the inner peripheral surface of the lens barrel 1. The edge portions 13, 23, 33, and 43 of the first lens 11, the second lens 21, the third lens 31, and the fourth lens 41 are in contact with the inner peripheral surface of the lens barrel 1. The subject side of the edge portion 13 of the first lens 11 is held by the tube portion 1a by caulking the tip portion of the tube portion 1a.

  The diameter of the first lens 11 is longer than the diameter of the second lens 21. The diameter of the second lens 21 is longer than the diameter of the third lens 31. The diameter of the third lens 31 is longer than the diameter of the fourth lens 41. In the following description, the first lens 11, the second lens 21, the third lens 31, and the fourth lens 41 are collectively referred to simply as a lens.

  2 is a cross-sectional view illustrating an example of the configuration of an imaging unit including the lens unit illustrated in FIG.

  The imaging unit 100 includes the lens unit 10 illustrated in FIG. 1, a sensor unit 101, an outer cover 102, a holder 103, a connection unit 108, and wiring 110.

  The sensor unit 101 includes a main body cover 105, an image sensor 106 built in the main body cover 105, and a sensor substrate 104 to which the image sensor 106 is attached. The image sensor 106 converts an image formed by the optical system 4 into an electrical signal. The image sensor 106 is, for example, a CCD image sensor or a CMOS image sensor.

  The sensor substrate 104 is a plate-like member that supports the imaging element 106 so that the imaging surface of the imaging element 106 is perpendicular to the optical axis of the optical system 4.

  The holder 103 is a frame-like member that holds the lens barrel 1. The holder 103 is fixed to the sensor substrate 104. Although not shown, the holder 103 has an inner peripheral surface that is screw-engaged with the outer peripheral surface of the cylindrical portion 1 a of the lens barrel 1.

  The outer cover 102 holds the outer periphery of the lens barrel 1 of the lens unit 10 and is fixed to the main body cover 101.

  The connection unit 108 connects a wiring extending from the sensor substrate 104 in the main body cover 105 to a wiring 110 extending outward from the main body cover 105.

  As shown in FIG. 1, a waterproof film 6 is formed on the inner peripheral surface of the lens barrel 1 at a site where the outer peripheral surface of the edge portion 13 of the first lens 11 contacts. The waterproof film 6 is pressed between the lens barrel 1 and the lens.

  The waterproof film 6 is formed by two-color molding on the inner peripheral surface of the cylindrical portion 1a. The waterproof film 6 is made of an elastic material as will be described later.

  3 is a cross-sectional view of the lens barrel of the lens unit of FIG. FIG. 3 shows a state cut along a cross section parallel to the central axis of the lens barrel 1. FIG. 4 is an enlarged view showing the lens barrel and the waterproof film in FIG. 3.

  As shown in FIG. 3, an annular groove 1 c centering on the central axis of the lens barrel 1 is formed on the inner peripheral surface of the tube portion 1 a. The waterproof film 6 is disposed in the groove 1c of the cylindrical portion 1a. The waterproof film 6 is formed so that the dimension in the direction parallel to the central axis of the lens barrel 1 is uniform. The waterproof film 6 is formed with a substantially uniform thickness (a dimension in the radial direction with respect to the central axis of the lens barrel 1) over the entire circumference.

  The waterproof film 6 is an elastic member having a predetermined crushing amount and a crushing rate as will be described later. By fitting the first lens 11 into the inner peripheral surface of the lens barrel 1, the waterproof film 6 is pressed between the lens barrel 1 and the first lens 11 and compressed with a repulsive force. Therefore, the space between the outer peripheral surface of the edge portion 13 of the first lens 11 and the inner peripheral surface of the lens barrel 1 is sealed by the waterproof film 6, and water enters the lens barrel 1 from the outside of the lens unit 10. This can be prevented.

  Further, since there is no need to use an O-ring or packing, the number of parts can be reduced, and the parts cost and the number of assembly steps can be reduced.

  As an elastic material constituting the waterproof film 6, nitrile rubber, ethylene propylene rubber, silicone rubber, fluorine rubber, acrylic rubber, butyl rubber, urethane rubber, or the like can be used.

  The material of the lens barrel 1 is polyamide resin (PA), polyphthalamide resin (PPA), polycarbonate resin (PC), polyphenylene sulfide resin (PPS), polybutylene terephthalate (PBT), polyether sulfone resin (PES), Polyphenylene ether resin (PPE), polyethylene resin (PE), polyarylate resin (PAR), liquid crystal polymer (LCP), polyether ether ketone resin (PEEK), polyimide resin (PI), polyamideimide resin (PAI), etc. are used. be able to.

  As the lens material, glass, PC, acrylic, cycloolefin-based material, or the like can be used.

  In addition, according to the lens unit 10 and the imaging unit 100 including the lens unit 10, there is no need to perform an operation of fitting the lens and the O-ring into the lens barrel 1, and the waterproof property due to improper fitting of the O-ring. Decrease can be avoided. Therefore, waterproofing can be performed reliably.

  Next, the squashing amount and squashing rate of the waterproof film 6 will be described with reference to FIG.

  As shown in FIG. 4, when the thickness of the waterproof film 6 is W and the depth of the groove 1c is H, the squashing amount δ can be expressed as δ = W−H. The waterproof film 6 preferably has a crushing amount δ of 0.05 mm to 0.5 mm, and more preferably 0.15 mm to 0.35 mm.

  As shown in FIG. 4, the squashing rate E of the waterproof film 6 can be expressed as (δ / W) × 100. The waterproof film 6 preferably has a crushing rate of 5% to 30%, and more preferably 15% to 25%.

  Next, a modified example of the present invention will be described. In the following description, the configuration of the lens unit of FIG.

FIG. 5 is a schematic cross-sectional view illustrating a modification of the configuration of the lens unit.
As shown in FIG. 5, an annular groove 13 a centering on the optical axis of the lens portion 12 is formed on the outer peripheral surface of the edge portion 13 of the eleventh lens. An annular waterproof film 6 is formed in the groove 13 a of the edge portion 13. The waterproof film 6 can be formed integrally with the first lens 11 by two-color molding using the material of the first lens 11 and the elastic material.

  In such a configuration, the same material as described above can be used as the elastic material and the lens material.

  Thus, in the present invention, the waterproof film 6 may be formed by multicolor molding over the entire circumference on the inner circumferential surface of the lens barrel 1 or the outer circumferential surface of the edge portion of any lens.

  As the material of the lens barrel 1, aluminum, brass, iron, stainless steel, PA, PPA, PC, PPS, PBT, PES, PPE, PE, PAR, LCP, PEEK, PI, PAI, or the like can be used.

  Thus, even in the configuration in which the waterproof film is molded in two colors on the lens side, by sealing the gap between the outer peripheral surface of the edge portion 13 of the first lens 11 and the inner peripheral surface of the lens barrel 1 with the waterproof film 6, Waterproofing of the lens unit can be realized. In addition, since there is no need to use an O-ring or packing, the number of parts can be reduced, and the parts cost and the number of assembly steps can be reduced. Further, it is not necessary to perform the operation of fitting the lens and the O-ring into the lens barrel 1, and it is possible to avoid a decrease in waterproofness due to improper fitting of the O-ring. Therefore, waterproofing can be performed reliably.

  The waterproof film 6 is not limited to be provided between the edge portion of the first lens 11 and the inner peripheral surface of the lens barrel, but may be provided between the edge portion of another lens and the lens barrel. Moreover, the waterproof film 6 should just be integrally shape | molded by the two-color molding in either the edge part or lens-barrel of another lens.

  The hardness of the elastic material is 90 or less for Shore A (JIS K6253), and more preferably in the range of 30 to 70.

  In the above-described example, two-color molding has been described. However, the present invention is not limited to this, and multicolor molding may be used. For example, three or more kinds of materials having different hardnesses may be used, and a lens or a lens barrel may be formed using two of them. In this case, the lens can be held with high accuracy in the hard elastic portion when there is no gap such as normal temperature, and when the gap is generated in a low temperature and high temperature environment, the soft elastic portion can be held without any looseness. As a combination, for example, a hard material having a Shore A50 or higher, desirably 50 to 70 is used, and a soft material having a Shore A50 or lower, preferably 30 to 50, is used.

  The above-described imaging unit is suitable for a camera that is required to be resistant to environmental temperature changes. For example, the imaging unit is suitable for a vehicle-mounted camera provided for back monitoring or front monitoring. In addition, the lens unit is suitable for being provided in the imaging unit.

This specification discloses the following matters.
(1) a plurality of lenses;
A lens unit that houses the plurality of lenses so that their optical axes coincide with each other,
Each of the plurality of lenses has a lens part and an edge part extending around the lens part,
The edge portion of at least one of the plurality of lenses is in contact with the inner peripheral surface of the lens barrel, and the inner peripheral surface of the lens barrel and the outer peripheral surface of the edge portion in contact with the inner peripheral surface; A waterproof membrane is formed between
The waterproof film is formed by multicolor molding over the entire circumference of the inner peripheral surface of the lens barrel or the outer peripheral surface of the edge portion of the lens, and is a lens unit that is pressed between the lens barrel and the lens. .
(2) The lens unit according to (1),
The waterproof film is a lens unit having a crushing rate of 5% to 30%.
(3) The lens unit according to (1) or (2),
The waterproof film is a lens unit whose crushing amount is 0.05 mm to 0.5 mm.
(4) An imaging unit comprising: a sensor unit having an imaging element; and a lens unit that forms an image on the imaging element,
The lens unit is an imaging unit which is the lens unit according to any one of (1) to (3).
(5) A lens housed in a cylindrical barrel,
The lens part,
An edge portion extending like a bowl around the lens portion;
A waterproof film is formed on the outer peripheral surface of the lens edge, which is fitted to the inner peripheral surface of the lens barrel.
The waterproof film is a lens formed by multicolor molding over the entire circumference of the outer peripheral surface of the edge portion.
(6) The lens according to (5),
The waterproof film is a lens having a crushing rate of 5% to 30%.
(7) The lens according to (5) or (6),
The waterproof film is a lens having a crushing amount of 0.05 mm to 0.5 mm.

DESCRIPTION OF SYMBOLS 1 Lens tube 1a Tube part 6 Waterproof film 10 Lens unit 11 1st lens (lens)
21 Second lens (lens)
31 Third lens (lens)
41 Fourth lens (lens)
100 Imaging unit 101 Sensor unit

Claims (7)

Multiple lenses,
A lens unit that houses the plurality of lenses so that their optical axes coincide with each other,
Each of the plurality of lenses has a lens part and an edge part extending around the lens part,
The edge portion of at least one of the plurality of lenses is in contact with the inner peripheral surface of the lens barrel, and the inner peripheral surface of the lens barrel and the outer peripheral surface of the edge portion in contact with the inner peripheral surface; A waterproof membrane is formed between
The waterproof film is formed by multicolor molding over the entire circumference of the inner peripheral surface of the lens barrel or the outer peripheral surface of the edge portion of the lens, and is a lens unit that is pressed between the lens barrel and the lens. . The lens unit according to claim 1,
The waterproof film is a lens unit having a crushing rate of 5% to 30%. The lens unit according to claim 1 or 2,
The waterproof film is a lens unit whose crushing amount is 0.05 mm to 0.5 mm. An imaging unit comprising: a sensor unit having an imaging element; and a lens unit that forms an image on the imaging element,
The imaging unit, wherein the lens unit is the lens unit according to claim 1. A lens housed in a cylindrical barrel,
The lens part,
An edge portion extending around the lens portion;
A waterproof film is formed on the outer peripheral surface of the lens edge, which is fitted to the inner peripheral surface of the lens barrel.
The waterproof film is a lens formed by multicolor molding over the entire circumference of the outer peripheral surface of the edge portion. The lens according to claim 5,
The waterproof film is a lens having a crushing rate of 5% to 30%. The lens according to claim 5 or 6, wherein
The waterproof film is a lens having a crushing amount of 0.05 mm to 0.5 mm.

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