JP2010197909A - Lens assembly - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens assembly having small size as a whole in which assembling property can be improved and desired optical characteristics can be easily obtained. <P>SOLUTION: On the outer circumferential surface of a first lens 5, there are formed a first equi-diameter outer circumferential surface 5a on an end on a second lens 4 side thereof and a first sloped outer circumferential surface 5b having a progressively smaller outer diameter from the first equi-diameter outer circumferential surface 5a toward an end face on an opposite side to the second lens 4. On the outer circumferential surface of the second lens 4, there are formed a second equi-diameter outer circumferential surface 4a on an end on the first lens 5 side thereof and a second sloped outer circumferential surface 4b having a progressively larger outer diameter from the second equi-diameter outer circumferential surface 4a toward an end face on an opposite side to the first lens 5. In a lens frame 1, there are formed a sloped inner peripheral surface L<SB>6</SB>for fitting the first sloped outer circumferential surface 5b of the first lens 5, a first equi-diameter inner peripheral surface L<SB>5</SB>for fitting the first equi-diameter outer circumferential surface 5a of the first lens 5, and a second equi-diameter inner peripheral surface L<SB>3</SB>for fitting the second equi-diameter outer circumferential surface 4a of the second lens 4. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a lens assembly including a plurality of lenses and a lens frame for holding them.

  For example, in an in-vehicle camera, a surveillance camera, a digital camera, a camera-equipped mobile phone, etc. for confirming the rear, left and right sides of the vehicle, etc. A solid is used.

  As such a lens assembly, for example, a receiving portion for positioning the lens in the optical axis direction is formed at one end portion of a lens frame, and a plurality of lenses are changed from a lens having a small outer diameter to a large lens on the receiving portion. Are inserted into the lens frame so as to be stacked in this order, and the surface edge of the uppermost lens is locked by a locking part formed at the other end of the lens frame (for example, patents) Reference 1).

JP 2007-121612 A

  However, in the lens assembly disclosed in Patent Document 1, the peripheral surface of each lens is formed in parallel to the optical axis direction (thickness direction). That is, the peripheral surface of each lens is formed in the same diameter over the thickness direction. The inner peripheral surface of the lens frame is also formed in a step shape in the optical axis direction in accordance with the outer diameter and the peripheral surface shape of each lens.

  For this reason, when each lens is inserted into the lens frame, the lens outer peripheral surface is caught by the inner peripheral surface of the corresponding inner diameter of the lens frame, the lens falls, or the lens optical axis is set to the predetermined lens frame. It becomes difficult to insert each lens in a predetermined posture, such as being inserted with an inclination relative to the optical axis. In particular, when inserting a plurality of lenses into a lens frame so as to be stacked, if the optical axis of the lens inserted earlier is tilted with respect to a predetermined optical axis, the optical axis of the lens inserted thereafter is also tilted. There is a concern that the optical performance will be lowered due to the insertion.

  In addition, the lens frame is formed in a stepped shape in the optical axis direction in accordance with the outer diameter and the peripheral surface shape of each lens, so that the lens frame has a predetermined thickness according to the inner peripheral surface shape. If secured, there is a concern that the portion having a large outer diameter increases, leading to an increase in the size of the entire lens assembly.

  Accordingly, an object of the present invention made in view of such a point is to provide a lens assembly which can improve assemblability, easily obtain desired optical characteristics, and can be reduced in size as a whole. .

The invention of the lens assembly according to claim 1, which achieves the above object, includes stacking at least two lenses, a first lens and a second lens having a larger outer diameter than the first lens, on a lens frame. In the holding lens assembly,
On the outer peripheral surface of the first lens, a first outer peripheral surface having the same diameter is formed at the end on the second lens side, and from the outer surface having the same diameter to the end surface on the side opposite to the second lens. Forming a first inclined outer peripheral surface having a continuously decreasing outer diameter,
On the outer peripheral surface of the second lens, a second outer peripheral surface having the same diameter is formed at an end portion on the first lens side, and the second outer surface having the same diameter is directed to an end surface opposite to the first lens. Forming a second inclined outer peripheral surface whose outer diameter continuously increases,
An inclined inner peripheral surface into which the first inclined outer peripheral surface of the first lens fits in the lens frame, a first inner diameter with the same diameter as the first outer peripheral surface of the first lens, And the 2nd same diameter inner peripheral surface in which the 2nd same diameter outer peripheral surface of the 2nd lens fits was formed,
It is characterized by this.

The invention according to claim 2 is the lens assembly according to claim 1,
The lens frame includes a lens end surface support portion formed at an end portion on the first lens side, and a lens edge whole circumference support portion formed at an end portion on the second lens side,
Between the first lens and the lens end surface support portion, there is an elastic member from the lens end surface support portion side toward the first lens side, and a third lens having an outer diameter smaller than that of the first lens. Arranged,
A fourth lens having an outer diameter larger than that of the second lens is provided between the second lens and the lens edge all-around support portion, and the surface edge of the fourth lens extends over the entire circumference. The third lens, the first lens, the second lens, and the fourth lens are disposed by being supported by an entire periphery support portion, and between the lens end surface support portion and the lens edge entire periphery support portion. , Elastically pressed and held by the elastic member,
The fourth lens has a recess formed over the entire periphery at the end surface edge on the second lens side, and a seal member is disposed between the recess and the inner peripheral wall surface of the lens frame. Yes,
It is characterized by this.

The invention according to claim 3 is the lens assembly according to claim 1 or 2,
A flare stop is disposed between the first lens and the second lens.
It is characterized by this.

  According to the present invention, the first inclined outer peripheral surface of the first lens is guided by the first inclined inner peripheral surface of the lens frame so that the first lens can be smoothly inserted into the lens frame, and the first lens of the first lens can be inserted. The optical axis of the first lens can be positioned by fitting the outer peripheral surface of the same diameter into the first inner peripheral surface of the lens frame. Further, the second lens has an outer peripheral surface with the same diameter as the second lens and is fitted into the inner peripheral surface with the second diameter of the lens frame, thereby positioning the optical axis without affecting the posture of the first lens. , Can be inserted smoothly into the lens frame. Therefore, the assemblability can be improved and desired optical characteristics can be easily obtained. In addition, since the inclined outer peripheral surface is formed on each of the first lens and the second lens, the large portion of the outer diameter of the lens frame can be reduced while ensuring the thickness of the lens frame, and the entire lens assembly can be reduced in size. Can be planned.

It is sectional drawing which shows typically the structure of the lens assembly which concerns on one embodiment of this invention. It is a disassembled perspective view of the lens assembly shown in FIG. It is the front view and side view which show the elastic member shown in FIG.

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

  FIG. 1 is a sectional view schematically showing a configuration of a lens assembly according to an embodiment of the present invention, and FIG. 2 is an exploded perspective view thereof.

  As shown in FIGS. 1 and 2, the lens assembly according to this embodiment includes a lens frame 1, a fourth lens 3, a second lens 4, a first lens 5, and a first lens in order along the optical axis O. A lens group M composed of four lenses of three lenses 6 is held. The maximum outer diameter of each lens decreases in the order of the fourth lens 3, the second lens 4, the first lens 5 and the third lens 6. In this specification, for the sake of convenience, the fourth lens 3 side is referred to as the object side (left side of the paper), and the third lens 6 side is referred to as the image side (right side of the paper). In each lens, the object-side surface is also referred to as the front surface, and the image-side surface is also referred to as the rear surface.

  The lens frame 1 is composed of an annular peripheral wall made of plastic or metal material, and has an object side opening 1a and an image side opening 1b opened toward the object side and the image side, respectively. The light enters the lens frame 1 from the side opening 1a, passes through the lens group M, and exits from the image side opening 1b.

  At the image side end portion of the lens frame 1, a stop wall 2a that forms a lens end surface support portion of the lens group M and forms an image side opening 1b is provided. The image side opening 1b is formed in the diaphragm wall 2a so as to expose the central portion including the optical axis of the third lens 6 positioned on the image side.

The fourth lens 3 is made of a glass concave meniscus lens, and is supported on the lens frame 1 by a lens edge all-around support portion 2b formed by caulking of the object side end of the lens frame 1 with the object side as a convex surface. Yes. The fourth lens 3 is fits in the diameter inner peripheral surface L ₁ to the diameter outer peripheral surface 3a is formed on the lens frame 1, the peripheral portion of the convex surface is chamfered portion 3b along the entire periphery formed Has been. The chamfered portion 3b is supported over the entire periphery by a caulking lens edge circumferential support portion 2b, and the lens edge circumferential support portion 2b forms an object-side opening 1a. Here, as shown in a partially enlarged view of FIG. 1, the entire lens edge support portion 2 b supports the chamfered portion 3 b so that the chamfered portion 3 b continues with a curvature substantially equal to the convex surface. Further, the outer peripheral surface side corner 3d of the chamfered portion 3b is rounded.

Also, the fourth lens 3, the rear edge being concave 3c over the entire periphery is formed and between the same diameter inner peripheral surface L ₂ formed in the recess 3c and the lens frame 1, for example, A seal member 10 made of an O-ring is sandwiched. The diameter of the diameter inner peripheral surface L ₂ is smaller than the diameter of the diameter inner peripheral surface L _1.

The second lens 4 is made of a plastic concave meniscus lens. On the outer peripheral surface thereof, an outer peripheral surface having the same diameter (second outer peripheral surface having the same diameter) 4a is formed at the end of the concave surface. An inclined outer peripheral surface (second inclined outer peripheral surface) 4b whose outer diameter continuously increases from the outer peripheral surface 4a toward the convex surface side is formed. Then, the second lens 4 is a convex surface as an object side, the diameter outer peripheral portion 4a, the diameter inner peripheral surface formed on the lens frame 1 (second same diameter inner peripheral surface) L ₃ in fits inclusive, inclined outer circumferential surface 4b is arranged located in the same diameter inner peripheral surface L ₄ formed on the lens frame 1. The diameter of the diameter inner peripheral surface L ₃ is smaller than the diameter of the diameter inner peripheral surface L _4. In addition, a contact portion 4 c that is in surface contact with the rear surface of the fourth lens 3 is formed on the front surface of the second lens 4 via the flare stop 7.

The first lens 5 is made of a plastic convex meniscus lens, and has a flange portion. The outer peripheral surface of the flange portion has an outer peripheral surface 5a (first diameter) at the end of the convex surface having a small curvature. 1) and an inclined outer peripheral surface (first inclined outer peripheral surface) 5b whose outer diameter continuously decreases from the outer peripheral surface 5a of the same diameter toward the convex surface having a large curvature. ing. Then, the first lens 5, a small convex curvature as the object side, the diameter outer peripheral surface 5a is the same diameter inner peripheral surface formed on the lens frame 1 (first same diameter inner peripheral surface) fitted to L ₅ Mari inclusive, inclined outer peripheral surface 5b is arranged fits the inclined inner peripheral surface L ₆ formed on the lens frame 1. The inclination in the peripheral surface L ₆ is formed from the same diameter inner peripheral surface L ₅ so that the diameter becomes smaller toward the image side. Further, in the same manner as the second lens 4, a contact portion 5 c that is in surface contact with the rear surface of the second lens 4 is formed on the front surface of the flange portion of the first lens 5 via the flare stop 8.

The third lens 6 is made of a plastic convex meniscus lens, has a flange portion, and the outer peripheral surface 6a having the same diameter of the flange portion is formed on the lens frame 1 with the convex side having a small curvature as the image side. They are arranged fits in the diameter inner peripheral surface L ₇ that is. On the front surface of the flange portion of the third lens 6, an abutting portion 6 b that is in surface contact with the rear surface of the first lens 5 is formed via the aperture stop 9 in the same manner as the first lens 5. The third lens 6 is disposed so that the central portion of the image-side convex surface protrudes from the image-side opening 1 b formed by the diaphragm wall 2. In addition, each outer peripheral surface edge part of the 2nd lens 4, the 1st lens 5, and the 3rd lens 6 is chamfered as needed.

  The flare stop 7 is disposed between the fourth lens 3 and the second lens 4, the flare stop 8 is disposed between the second lens 4 and the first lens 5, and the aperture stop 9 is The first lens 5 and the third lens 6 are disposed. The flare stops 7 and 8 prevent harmful light that does not contribute to photographing and the like from being transmitted. The flare stops 7 and 8 are made of a sheet-like member such as a polyester sheet, and the surface thereof is coated with a black paint to prevent reflection. Matting treatment is applied. The aperture stop 9 controls the brightness by limiting the diameter of the on-axis light beam that passes through the lens group M, and, like the flare stops 7 and 8, is composed of a sheet-like member such as a polyester sheet. The surface is subjected to a matting treatment such as application of a black paint to prevent reflection. The flare stops 7 and 8 and the aperture stop 9 can also be configured by directly applying a black paint to the end face of the lens or by applying a matte treatment.

An elastic member 11 made of a leaf spring is disposed between the third lens 6 and the diaphragm wall 2. The elastic member 11 by the repulsive force generated by pushing when installing the fourth lens 3 in the same diameter inner peripheral surface _{L 1,} a 7,8,9 aperture end faces of the lenses 3, 4, 5, 6 The lenses 3, 4, 5, 6 are positioned in the optical axis direction inside the lens frame 1 by elastically contacting (elastically supporting) each other.

  3A and 3B are a front view and a side view of the elastic member 11, respectively. The elastic member 11 includes a thin annular base 11a having an opening larger than the image side opening 1b formed in the diaphragm wall 2 and capable of passing through the central portion of the third lens 6, and an outer edge of the annular base 11a. And a plurality of arms (plate-like ones) 11b that are integrally connected in a single-side supported state. The arm 11b is bent at the base portion in the thickness direction so as to act as an elastic piece, and when a repulsive force is generated in the arm 11b, the tip is prevented from spreading outward in the radial direction. is doing.

  A stopper 12 is provided on the inner surface of the diaphragm wall 2 in the vicinity of the image side opening 1b. When the external stress such as an impact is applied to the lens assembly, the stopper 12 is arranged so that the stopper 12 has an image side opening of the third lens 6 before the opening edge portion 12a that defines the image side opening 1b. This is in contact with a region radially outside the effective region corresponding to 1b to prevent the effective region of the third lens 6 from being damaged. In addition, this stopper 12 can also be comprised by the some protrusion arrange | positioned at an annular convex part or space | interval.

  Next, an example of the assembly procedure of the lens assembly according to the present embodiment will be described.

  First, the lens frame 1 in which the image side opening 1b and the stopper 12 are formed on the diaphragm wall 2, with the object side opening positioned upward, from the object side opening, the elastic member 11, the third lens 6, The aperture stop 9, the first lens 5, the flare stop 8, the second lens 4, and the flare stop 7 are inserted so as to be sequentially stacked (dropped). Next, the fourth lens 3 is pushed into the lens frame 1 against the elastic force of the elastic member 11 so as to be stacked on the flare diaphragm 7 together with the seal member 10. In this state, the object side end of the lens frame 1 is thermally or mechanically deformed by caulking, so that the chamfered portion 3b formed on the front surface of the fourth lens 3 extends over the entire circumference and the front surface. Are supported by the lens edge circumferential support portion 2b so as to be continuous with a curvature substantially equal to the convex surface of the lens, and the object side opening 1a is formed by the lens edge circumferential support portion 2b.

  As a result, the lenses 3, 4, 5, 6 and the diaphragms 7, 8, 9 are moved between the lens edge all-around support portion 2b of the lens frame 1 and the diaphragm wall 2, that is, the object side opening 1a and the image side opening. 1b between the end faces of the lenses 3, 4, 5 and 6 through the diaphragms 7, 8, and 9 by the elastic force of the elastic member 11, and positioning in the optical axis direction. Can be held.

As described above, in the lens assembly according to the present embodiment, the outer peripheral surface of the flange portion of the first lens 5 is the outer peripheral surface 5a having the same diameter on the second lens 4 side, and the outer peripheral surface having the same diameter on the third lens 6 side. The inclined outer peripheral surface 5b has a smaller outer diameter than 5a. Also, with this the lens frame 1 of the portion where the first lens 5 is held, in accordance with the peripheral shape of the first lens 5, inclined outer peripheral surface 5b to form an inclined inner peripheral surface L ₆ of writing fits, forms of the same diameter inner peripheral surface L ₅ of the diameter outer peripheral surface 5a is writing fits. Therefore, in assembling the lens assembly, when inserting the first lens 5 from the inclined outer peripheral surface 5b side lens frame 1, the inclined outer peripheral surface 5b smoothly guided by the inclined inner peripheral surface L ₆ of the lens frame 1 insertion can further by the diameter outer peripheral surface 5a of the first lens 5 is fitted in the same diameter inner peripheral surface L ₅ of the lens frame 1, it is possible to position the optical axis of the first lens 5.

Further, the outer peripheral surface of the second lens 4 having a large outer diameter inserted subsequent to the first lens 5 has the same outer peripheral surface 4a on the first lens 5 side and the outer peripheral surface 4a on the fourth lens side. The inclined outer peripheral surface 4b is increased in diameter. In addition, an inner peripheral surface L ₃ having the same diameter into which the outer peripheral surface 4 a having the same diameter is fitted is formed in the portion of the lens frame 1 where the second lens 4 is held. Therefore, when the second lens 4 is inserted into the lens frame 1 from the same-diameter outer peripheral surface 4a side by the radially outer circumferential surface 4a is fitted in the same diameter inner peripheral surface L ₃ of the lens frame 1, it is inserted into previously The optical axis of the second lens 4 can be positioned and inserted smoothly without affecting the posture of the first lens 5.

  Thereby, assembly property can be improved and desired optical characteristics can be easily obtained. Moreover, since the inclined outer peripheral surface 5b is formed on the first lens 5 and the inclined outer peripheral surface 4b is formed on the second lens 4, the entire outer peripheral surface of the first lens 5 is formed without forming these inclined outer peripheral surfaces. When the outer peripheral surface of the second lens 4 has the same outer diameter as the maximum outer diameter of the inclined outer peripheral surface 4b, the outer peripheral surface of the second lens 4 has the same outer diameter as the outer peripheral surface of the same diameter. As compared with the lens frame 1, it is possible to reduce the portion of the lens frame 1 having a large outer diameter while securing the thickness of the lens frame 1, so that the entire lens assembly can be downsized.

Between the same diameter inner peripheral surface L ₂ of the recess 3c and lens frame 1 of the fourth lens 3, since the clamping of the sealing member 10, to enable the dust from entering from the object side to the lens frame 1 It can be prevented and a waterproof effect can be obtained. Therefore, for example, when mounted as a photographic lens assembly on a surveillance camera or the like, it can be used stably over a long period of time. In addition, an elastic member 11 that elastically presses the third lens 6 toward the fourth lens 3 is disposed between the third lens 6 and the diaphragm wall 2 that constitutes the lens end surface support portion. Thus, the end surfaces of the lenses 3, 4, 5, and 6 can be elastically pressed to each other through the diaphragms 7, 8, and 9, and can be positioned and held in the optical axis direction. Further, since the flare stops 7 and 8 are disposed between the fourth lens 3 and the second lens 4 and between the second lens 4 and the first lens 5, respectively, it is possible to reliably prevent the occurrence of flare. Can do.

  Further, according to the lens assembly according to the present embodiment, the chamfered portion 3b is formed on the lens surface edge portion of the front surface of the fourth lens 3 facing the object side, and the chamfered portion 3b is substantially the same as the front lens surface. Since it is supported by the lens edge all-around support portion 2b of the lens frame 1 so as to be continuous with an equal curvature, the diameter of the fourth lens 3 is compared with the case where the lens portion is supported by forming a flange portion other than the lens surface. Accordingly, the outer diameter of the lens frame 1 can be reduced, so that the entire lens assembly can be reduced in size, and the processing of the fourth lens 3 can be facilitated, thereby reducing the cost. In addition, since the entire circumference of the chamfered portion 3b is supported by the lens edge whole circumference support portion 2b, the fourth lens 3 is stably held with sufficient holding strength without causing an optical axis shift due to an external impact. It becomes possible.

  Further, since the chamfered portion 3b rounds the outer peripheral surface side corner portion 3d, the lens edge all-round support portion 2b is formed by caulking, the state in which the fourth lens 3 is held on the lens frame 1, and external stress. During the operation, the stress on the fourth lens 3 can be dispersed, thereby preventing the optical performance from being deteriorated due to distortion.

  The fourth lens 3 facing the object side is a glass lens, the other lenses 4, 5, and 6 are plastic lenses, and the third lens 6 facing the image side is a diaphragm wall 2a that constitutes a lens end surface support portion. Since the lens assembly is supported on the inner surface of the lens assembly, the lens assembly can be reduced in weight while effectively preventing damage to the lens held by the lens assembly, and distortion of the fourth lens 3 can be further reduced. Therefore, it is possible to more reliably prevent the optical performance from being deteriorated. In addition, since the aperture stop 9 is disposed between the first lens 5 and the third lens 6, the diameter of each lens can be made smaller, and can be made smaller from the fourth lens 3 toward the third lens 6 in order. Thereby, the internal shape of the lens frame 1 can be easily formed so that the third lens 6 can be dropped in the order of the first lens 5, the second lens 4, and the fourth lens 3, and the assemblability can be improved and the lens assembly can be improved. Three-dimensional size and weight can be reduced.

  The present invention is not limited to the above-described embodiment, and many variations or modifications are possible. For example, the lens group M held in the lens assembly is not limited to four lenses, and the present invention can be applied effectively when there are at least two lenses. Further, the elastic member 11 can have an arbitrary shape, and a rubber member may be used in place of the plate-like spring, or may be omitted.

DESCRIPTION OF SYMBOLS 1 Mirror frame 1a Object side opening 1b Image side opening 2a Diaphragm wall 2b Lens edge whole periphery support part 3 4th lens 3a Same diameter outer peripheral surface 3b Chamfer 3c Concave part 3d Outer peripheral side corner 4 Second lens 4a Same diameter outer peripheral surface 4b Inclined outer peripheral surface 4c Contact portion 5 First lens 5a Same diameter outer peripheral surface 5b Inclined outer peripheral surface 5c Contact portion 6 Third lens 6a Same diameter outer peripheral surface 6b Contact portion 7, 8 Flare stop 9 Aperture stop 10 Sealing member 11 elastic members 11a annular base 11b arm 12 stopper 12a opening edge M lens group _{L 1} ~L _5, L ₇ same diameter inner peripheral surface L ₆ inclined inner peripheral surface

Claims (3)

In a lens assembly in which at least two lenses, a first lens and a second lens having a larger outer diameter than the first lens, are held so as to be stacked on a lens frame.
On the outer peripheral surface of the first lens, a first outer peripheral surface having the same diameter is formed at the end on the second lens side, and from the outer surface having the same diameter to the end surface on the side opposite to the second lens. Forming a first inclined outer peripheral surface having a continuously decreasing outer diameter,
On the outer peripheral surface of the second lens, a second outer peripheral surface having the same diameter is formed at an end portion on the first lens side, and the second outer surface having the same diameter is directed to an end surface opposite to the first lens. Forming a second inclined outer peripheral surface whose outer diameter continuously increases,
An inclined inner peripheral surface into which the first inclined outer peripheral surface of the first lens fits in the lens frame, a first inner diameter with the same diameter as the first outer peripheral surface of the first lens, And the 2nd same diameter inner peripheral surface in which the 2nd same diameter outer peripheral surface of the 2nd lens fits was formed,
A lens assembly characterized by that. The lens frame includes a lens end surface support portion formed at an end portion on the first lens side, and a lens edge whole circumference support portion formed at an end portion on the second lens side,
Between the first lens and the lens end surface support portion, there is an elastic member from the lens end surface support portion side toward the first lens side, and a third lens having an outer diameter smaller than that of the first lens. Arranged,
A fourth lens having an outer diameter larger than that of the second lens is provided between the second lens and the lens edge all-around support portion, and the surface edge of the fourth lens extends over the entire circumference. The third lens, the first lens, the second lens, and the fourth lens are disposed by being supported by an entire periphery support portion, and between the lens end surface support portion and the lens edge entire periphery support portion. , Elastically pressed and held by the elastic member,
The fourth lens has a recess formed over the entire periphery at the end surface edge on the second lens side, and a seal member is disposed between the recess and the inner peripheral wall surface of the lens frame. Yes,
The lens assembly according to claim 1. A flare stop is disposed between the first lens and the second lens.
The lens assembly according to claim 1, wherein the lens assembly is a lens assembly.

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