JP2012215709A - Lens unit, lens, and imaging unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens unit, a lens, and an imaging unit capable of suppressing deterioration in optical performance.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 inside surface of the lens barrel, a compensatory part is formed, by multi-color molding, on either one of the lens or the lens barrel between the inside surface of the lens barrel and the surface of the edge part abutting on the inside surface, and materials of the compensatory part has a smaller elastic modulus than materials of the lens and the lens barrel.

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.

  The imaging device described in Patent Literature 2 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 2009-95000 A JP 2004-295119 A

  By the way, the lens unit used for the imaging unit may be thermally deformed due to a difference in linear expansion coefficient between the lens and the lens barrel depending on the temperature and temperature of the usage environment, and a gap may be formed between the two. As a result, the lens barrel collapses or the shaft shifts in the lens barrel, and the optical performance may deteriorate.

  In the case of the configuration in which the lens and the O-ring are fitted into the lens barrel as in Patent Document 2, the work of fitting is complicated, and the mistake of forgetting to fit the O-ring or improper fitting of the O-ring causes the O-ring to be fitted. There is a concern that the posture is twisted and a gap is formed between the lens and the lens barrel.

  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 suppress deterioration in optical performance.

(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 lens of the plurality of lenses is in contact with the inner surface of the lens barrel, and between the inner surface of the lens barrel and the surface of the edge portion in contact with the inner surface, A compensation portion is formed by multicolor molding on either the lens or the lens barrel,
The material of the filling portion is a lens unit having a smaller elastic modulus than the material of the lens and the lens barrel.
(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;
In the surface of the edge portion of the lens, a portion that contacts the inner surface of the lens barrel is formed with a compensation portion by multicolor molding,
The material of the filling portion is a lens having a smaller elastic modulus than the material of the lens and the lens barrel.

  According to the present invention, it is possible to provide a lens unit, a lens, and an imaging unit that can suppress deterioration in optical performance.

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 drawing of the lens frame of the lens unit of FIG. The figure which shows typically the state which looked at 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 in order from the incident side (left side in the figure).

  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 extending around the lens part 42.

  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 105.

  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 compensation portion 6 is formed between the surface of the edge portion 13 of the first lens 11 and the inner surface of the lens barrel 1. Further, a compensation portion 9 is formed between the surface of the fourth lens 41 opposite to the subject side of the edge portion 43 and the bottom portion 1 b of the tube portion 1 a of the lens barrel 1.

  The filling portions 6 and 9 are formed on the inner peripheral surface of the tube portion 1a of the lens barrel 1 by two-color molding. The filling parts 6 and 9 are both made of an elastic material as will be described later.

  Here, in the two-color molding of the lens barrel 1, the cylindrical portion 1a is molded with the first resin constituting the cylindrical portion 1a by the primary molding, and then the second molding is performed on the cylindrical portion 1a. The filling parts 6 and 9 are molded with resin.

  3 is a cross-sectional view of the lens frame 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. In FIG. 3, the region indicated by the crossed diagonal lines indicates a portion where the filling portion 6 is formed.

  As shown in FIG. 3, the compensation portion 6 is formed from the stepped portion 7 on the inner surface of the lens barrel 1 to the subject side end of the lens barrel 1. The compensation portion 9 is formed in an annular shape around the central axis of the tube portion 1 a of the lens barrel 1.

  That is, the outer peripheral surface of the edge portion 13 of the first lens 11 abuts on the compensation portion 6. In other words, the edge portion 13 of the first lens 11 is elastically supported by the inner surface of the lens barrel 1 in the radial direction of the central axis of the lens barrel 1 with the compensation portion 6 interposed therebetween. Further, the surface of the edge portion 43 of the fourth lens 41 opposite to the subject side is in contact with the compensation portion 9. In other words, the edge portion 43 of the fourth lens 41 is elastically supported in the axial direction of the lens barrel 1 with the compensation portion 9 interposed therebetween.

  The material of the compensation parts 6 and 9 has a smaller elastic modulus than the material of the lens and the lens barrel 1. Nitrile rubber, ethylene propylene rubber, silicone rubber, fluorine rubber, acrylic rubber, butyl rubber, urethane rubber, or the like can be used as the elastic material constituting the filling parts 6 and 9.

  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.

  When the lens or the lens barrel 1 undergoes thermal deformation due to the difference in linear expansion coefficient in a high temperature or low temperature environment, the compensating portions 6 and 9 appropriately expand and contract between the lens and the lens barrel 1 as the lens deforms. . At normal temperature, a part of the outer peripheral surface of the edge portion 13 of the first lens 11 (the portion not in contact with the compensation portion 6) is in direct contact with the inner peripheral surface of the cylindrical portion 1a, is accurately positioned, and the temperature changes. In this case, even if a gap is generated between the edge portion 13 and the cylindrical portion 1a, the edge portion 13 of the first lens 11 is supported by the cylindrical portion 1a via the compensation portion 6. The compensation unit 9 is pressed by the fourth lens 41 and crushed to the bottom 1b side at room temperature. In this state, a part of the surface of the edge portion 43 of the fourth lens 41 (a portion other than the portion in contact with the compensation portion 9) is directly abutted against the bottom portion 1b, so that the fourth lens 41 is accurately positioned. can do. Even if a gap is generated between the edge portion 43 and the bottom portion 1b of the fourth lens 41 due to the temperature change, the fourth lens 41 is supported by the bottom portion 1b by the compensation portion 9, and hence it is possible to prevent the fourth lens 41 from rattling. . For this reason, it can suppress that a clearance gap arises between a lens and the lens-barrel 1. Therefore, according to the lens unit 10 and the imaging unit 100, it is possible to prevent the lens from being tilted or the shaft from being displaced in the lens barrel and the optical performance from being deteriorated.

  For example, when the linear expansion coefficient of the lens barrel 1 is smaller than the linear expansion coefficient of the lens, a gap is generated between the lens and the lens barrel 1 at a low temperature, but can be held without any gap by the compensating portions 6 and 9. . As a combination of a lens and a lens barrel that have such a linear expansion coefficient relationship, when the lens barrel 1 is aluminum and the lens is plastic, the lens barrel 1 is plastic (glass fiber reinforced plastic), An example is when the lens is plastic.

  For example, when the linear expansion coefficient of the lens barrel 1 is larger than the linear expansion coefficient of the lens, a gap is generated between the lens and the lens barrel 1 at a high temperature, but the lens can be held by the compensating portions 6 and 9 without any gap. As a combination of a lens and a lens barrel having such a relationship of linear expansion coefficients, when the lens barrel 1 is aluminum and the lens is glass, the lens barrel 1 is plastic and the lens is glass. Can be illustrated.

  It is desirable that the compensation parts 6 and 9 have dimensions that can compensate for dimensional changes due to temperature, and that the dimensional changes in the lens radial direction and the optical axis direction are 1 μm to 50 μm.

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

FIG. 4 is a diagram schematically illustrating a state in which the lens is perspective.
As shown in FIG. 4, the outer peripheral surface of the edge portion of the lens and the surface of the edge portion that is continuous with the lens portion surface (the annular region along the peripheral edge portion of the edge portion) are made of an elastic material by two-color molding A filling portion is formed. As described above, the filling portion formed in the gap between the edge portion of the lens and the inner side surface of the lens barrel may be formed on the lens side.

  In this way, even when the compensation part is formed in two colors on the lens side, when the lens or the lens barrel 1 is thermally deformed due to a difference in linear expansion coefficient, the compensation part 6 having a small elastic modulus is used as the lens. It is possible to prevent a gap from being formed between the lens and the lens barrel 1 by appropriately expanding and contracting between the lens and the lens barrel 1 in accordance with the deformation.

  Even when the compensation portion is formed in the lens as described above, the elastic material described above can be used. In addition to PA, PPA, PC, PPS, PBT, PES, PPE, PE, PAR, LCP, PEEK, PI, and PAI, the lens barrel is made of aluminum, brass, iron. Stainless steel can also be used. As the material of the lens, PC, acrylic, or cycloolefin-based material can be used.

  The lens shown in FIG. 4 also forms a lens unit by being fitted into the above-described lens barrel.

  The filling portions 6 and 9 formed on the inner surface of the lens barrel need not be provided on the entire circumference of the inner surface of the lens barrel. For example, it may be formed at equal intervals in the circumferential direction of the inner surface of the lens barrel, or may be formed only on a part thereof. For example, the filling portion 9 may have a shape in which a part of the annular shape is cut out.

  The filling portion formed on the outer peripheral surface of the edge portion of the lens need not be provided on the entire outer peripheral surface. For example, it may be formed at equal intervals in the circumferential direction of the outer peripheral surface of the edge portion, or may be formed only on a part thereof.

  1 is not limited between the fourth lens 41 and the bottom 1b. For example, it may be provided between the surface of the first lens 11 opposite to the subject side of the edge 13 and the stepped portion 7. Or you may provide a level | step-difference part in the inner surface of the cylinder part 1a, and between the edge parts 23 and 33 with the 2nd lens 21 and the 3rd lens 31 which contact | abut to this level | step-difference part.

  In this embodiment, since the edge portion 13 on the subject side of the first lens 11 is supported by the cylindrical portion 1a, it is preferable to provide the compensation portion 9 between the fourth lens 41 and the bottom portion 1b. In consideration of the lens holding form by the lens barrel and the difference in the material of the lens and the lens barrel, an appropriate compensation portion may be provided.

  The compensation part should just be provided in any one of the inner surface of the lens-barrel 1, and the edge part of a lens.

  When the compensation portions 6 and 9 are provided on the outer peripheral surface of the lens edge portion or a part of the inner surface of the lens barrel 1, the lens edge portion serves as a compensation portion on the inner surface of the lens barrel 1 when there is no gap such as room temperature. Since it is held by a surface that is not provided, the positional accuracy is high. Further, in a low temperature or high temperature environment, even if a gap is generated between the edge portion of the lens and the inner surface of the lens barrel 1, the backlash of the lens is caused by the interposition of the compensating portions 6 and 9 therebetween. It can be suppressed from occurring.

  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 two of them may be used to form the lens and the lens barrel. In this case, the lens can be held with high accuracy in the hard filling portion when there is no gap such as normal temperature, and when there is a gap in a low temperature and high temperature environment, the soft filling 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. Further, the above-described imaging unit is not limited to a vehicle-mounted camera, and is suitable for a camera mounted on a terminal such as a mobile phone.

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 lens of the plurality of lenses is in contact with the inner surface of the lens barrel, and between the inner surface of the lens barrel and the surface of the edge portion in contact with the inner surface, A compensation portion is formed by multicolor molding on either the lens or the lens barrel,
The material of the filling portion is a lens unit having a smaller elastic modulus than the material of the lens and the lens barrel.
(2) The lens unit according to (1),
The compensation portion is provided on a portion of the inner surface of the lens barrel that comes into contact with at least one of the outer peripheral surface of the edge portion and the surface of the edge portion connected to the lens portion surface.
(3) The lens unit according to (1) or (2),
The compensation unit is a lens unit that is formed in a plurality divided in the circumferential direction of the inner surface of the lens barrel.
(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 that is the lens unit according to (1) or (2).
(5) A lens housed in a cylindrical barrel,
The lens part,
An edge portion extending around the lens portion;
In the surface of the edge portion of the lens, a portion that contacts the inner surface of the lens barrel is formed with a compensation portion by multicolor molding,
The material of the filling portion is a lens having a smaller elastic modulus than the material of the lens and the lens barrel.
(6) The lens according to (5),
The compensation part is a lens provided on an outer peripheral surface of the edge part.
(7) The lens according to (5),
The compensation portion is a lens that is a surface of a region continuous with a lens portion surface in the edge portion.

DESCRIPTION OF SYMBOLS 1 Lens barrel 1a Tube part 6, 9 Compensation part 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 lens of the plurality of lenses is in contact with the inner surface of the lens barrel, and between the inner surface of the lens barrel and the surface of the edge portion in contact with the inner surface, A compensation portion is formed by multicolor molding on either the lens or the lens barrel,
The material of the filling portion is a lens unit having a smaller elastic modulus than the material of the lens and the lens barrel. The lens unit according to claim 1,
The compensation portion is provided on a portion of the inner surface of the lens barrel that comes into contact with at least one of the outer peripheral surface of the edge portion and the surface of the edge portion connected to the lens portion surface. The lens unit according to claim 1 or 2,
The compensation unit is a lens unit that is formed in a plurality divided in the circumferential direction of the inner surface of the lens barrel. An imaging unit comprising: a sensor unit having an imaging element; and a lens unit that forms an image on the imaging element,
The said lens unit is an imaging unit which is a lens unit of Claim 1 or 2. A lens housed in a cylindrical barrel,
The lens part,
An edge portion extending around the lens portion;
In the surface of the edge portion of the lens, a portion that contacts the inner surface of the lens barrel is formed with a compensation portion by multicolor molding,
The material of the filling portion is a lens having a smaller elastic modulus than the material of the lens and the lens barrel. The lens according to claim 5,
The compensation part is a lens provided on an outer peripheral surface of the edge part. The lens according to claim 5,
The compensation portion is a lens that is a surface of a region continuous with a lens portion surface in the edge portion.

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