JP2005309289A - Lens and assembled lens - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens and an assembled lens capable of keeping moldability satisfactorily and preventing the light made incident on an outer peripheral side than an effective diameter from reaching an imaging device and becoming harmful light even when it is an assembled lens positioned by making the lenses directly abut on each other. <P>SOLUTION: The assembled lens 1 is constituted by combining two or more optical lenses 12 and 13. In the assembled lens 1, the optical lens 12 has the effective diameter part, an annular rugged part which is positioned adjacently to the outer periphery of one surface of the effective diameter part and where annular rugged shape is formed, and a plane part positioned on the outside from the annular rugged part on a plane on the annular rugged part side and directly coming into contact with the other lens. Then, a ring-shaped light shielding plate 16 is held between the optical lens 12 and the optical lens 13 directly coming into contact with the plane part of the optical lens 12. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a lens used in a camera or the like and a combined lens in which a plurality of lenses are combined in the optical axis direction. More specifically, the present invention relates to a lens and an assembled lens that are incorporated in a lens barrel by adjoining adjacent lenses partially.

  2. Description of the Related Art Conventionally, there is a combination lens in which two or more lenses are combined in the optical axis direction and held in a lens barrel, and light incident from an opening on the subject side is guided to an image sensor disposed behind these lenses. In such a group lens, in general, light that is incident outside the effective diameter and is reflected / scattered by a lens surface, a lens barrel, or the like prevents harmful light (bailing glare: VG) due to reaching the imaging surface. Have been devised. This is because such a VG causes a decrease in the contrast of the image. For this purpose, for example, a light shielding plate is sandwiched between the outer peripheral portions of the effective diameter between the lenses. For example, in the image pickup apparatus described in Patent Document 1, a diaphragm is disposed between lenses to prevent VG from entering the light receiving surface of the image pickup element.

On the other hand, in recent years, in order to cope with the downsizing and the increase in the number of pixels of such an assembled lens, the required accuracy of the distance between adjacent lenses in the optical axis direction has increased. For this reason, in order to make the lens interval more accurate, for example, in the technique disclosed in Patent Document 2, the edge portions of adjacent lenses are directly brought into contact with each other for positioning. As a result, the distance between adjacent lenses in the optical axis direction is accurately positioned.
Japanese Patent Laid-Open No. 2002-139661 (FIG. 1) JP 2004-61623 A (FIG. 1)

  However, when the above-described conventional techniques are used in combination, there are the following problems. That is, it is a combined lens configured such that the edge portions of adjacent lenses are in direct contact with each other and the light shielding plate is sandwiched between them, such as the combined lens 100 shown in FIG. In this combined lens 100, the light shielding plate 16 is sandwiched between the edge portions of the optical lens 101 and the optical lens 13, and a contact portion 18 where the both lenses 101 and 13 are directly contacted is provided on the outer peripheral side. Yes. In the contact portion 18, both members on both sides are transparent so that light can be transmitted.

  Here, the optical lens 101 is a resin-made transparent lens. From the viewpoint of the moldability of the resin, a sudden change in thickness is not desirable on the outer circumference side of the effective diameter. In particular, when a large thick part is formed in the immediate vicinity of the effective diameter, there is a risk that the dimensional accuracy inside the effective diameter may be reduced due to the sink of the thick part. Therefore, since it is necessary to make the thickness almost equal to the effective diameter immediately on the outer peripheral side of the effective diameter, the flat surface portion 101a is provided.

  The flat portion 101a reflects light on its surface. Furthermore, as shown in the figure, incident light L1 outside the effective incident angle is reflected by the flat surface portion 101a, and may be repeatedly reflected on both surfaces of the optical lens 101 to travel inside. The light traveling in this way has a problem that it passes through the contact portion 18 and reaches the image pickup surface 21a of the image pickup device 21 to become VG.

  The present invention has been made in order to solve the problems of the above-described conventional combination lens. In other words, the problem is that even in the case of an assembled lens that is positioned by bringing the lenses into direct contact with each other, the moldability is kept good and the light incident on the outer peripheral side from the effective diameter reaches the image sensor and is harmful. An object of the present invention is to provide a lens and a combined lens which are prevented from becoming light.

  The lens of the present invention, which has been made for the purpose of solving this problem, has an effective diameter part, an annular uneven part that is positioned adjacent to the outer periphery of one surface of the effective diameter part, and has an annular uneven shape, And a flat surface portion located outside the annular uneven portion on the surface of the uneven portion side.

  According to the lens of the present invention, since the annular concavo-convex portion is formed on the outer periphery of the effective diameter portion, the light incident on the outer peripheral side from the effective diameter always passes through the annular concavo-convex portion. Further, since this annular concavo-convex portion is formed on only one surface of the lens, there is no portion parallel to the other surface of the lens. Therefore, light does not travel repeatedly between parallel surfaces. Therefore, even when the flat part provided on the outer periphery is in direct contact with another lens to form a part that can transmit light, the light incident on the outer peripheral side of the effective diameter part is so far. Never reach. Thereby, even if the lens is used in a lens assembly that is positioned by bringing the lenses into direct contact with each other, it is possible to prevent light incident on the outer peripheral side from the effective diameter from reaching the image sensor and becoming harmful light.

Furthermore, in the present invention, it is desirable that the annular concavo-convex part is provided with at least one pair of annular convex part and annular concave part.
In such a case, since a large thick portion is not formed on the outer periphery of the effective diameter portion, sink marks are prevented and good moldability is maintained.

  In addition, the group lens of the present invention is a group lens formed by combining two or more lenses, and at least one lens is positioned adjacent to the effective diameter portion and the outer periphery of one surface of the effective diameter portion. An annular concavo-convex portion formed on the surface of the annular concavo-convex portion, and a plane portion located outside the annular concavo-convex portion on the surface of the annular concavo-convex portion and in direct contact with another lens. A ring-shaped light shielding member is sandwiched between the lens and the lens that is in direct contact with the flat surface.

  According to the assembled lens of the present invention, the lens interval is accurately positioned by being in direct contact with the other lens through the plane portion. Further, since the light incident on the outer peripheral side of the effective diameter portion does not reach the flat portion and is shielded by the light shielding member, harmful light is prevented.

  Furthermore, in the combined lens of the present invention, it is desirable that at least one set of an annular convex portion and an annular concave portion is provided on the annular concave and convex portion.

  According to the lens and the combined lens of the present invention, even when the lenses are positioned in direct contact with each other, the moldability is kept good, and the light incident on the outer peripheral side from the effective diameter reaches the image sensor and causes harmful light. It is prevented from becoming.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the best mode for embodying the present invention will be described in detail with reference to the accompanying drawings. In this embodiment, the present invention is applied to a combined lens used in a digital camera or the like.

  As shown in FIG. 1, the group lens 1 of this embodiment has four optical lenses 11, 12, 13, and 14 assembled to the lens barrel 15 in this order from the subject side. Further, between the optical lens 12 and the optical lens 13 and between the optical lens 13 and the optical lens 14, ring-shaped light shielding plates 16 and 17 are sandwiched between the respective edge portions. Each of the four optical lenses 11 to 14 is a resin-made transparent lens, and is fixedly bonded to the lens barrel 15. Further, the edge portion of the optical lens 12 and the optical lens 13 is in direct contact with the outer peripheral side of the light shielding plate 16 to form a contact portion 18. This portion can transmit light.

  Furthermore, this group lens 1 has an element holding portion 22 that holds the image pickup device 21 at the right end in the figure, and the lens barrel 15 and the element holding portion 22 are locked by a locking frame 23 while maintaining an appropriate distance. ing. Further, a filter 24 is disposed between the optical lens 14 and the image sensor 21. As a result, incident light incident from the opening of the lens barrel 15 forms an image on the imaging surface 21 a of the imaging device 21. Here, as the filter 24, for example, an infrared absorption filter, a low-pass filter, an ND filter, or a combination of these is used.

  Hereinafter, the subject side surface (left side in the figure) of each of the lenses 11 to 14 is referred to as a front surface, and the image sensor 16 side surface (right side in the figure) is referred to as a rear surface. For example, the contact portion 18 is a portion where the rear surface of the edge portion of the optical lens 12 is in contact with the front surface of the edge portion of the optical lens 13. In addition, the entire front surface of the edge portion of the optical lens 12 is fixed to the lens barrel 15.

  Next, the optical lens 12 will be described. The rear surface of the optical lens 12 is as shown in FIG. That is, it has annular triangular peaks 32 and 32 around the effective diameter portion 31 at the center, and further has a flat portion 33 on the outer periphery thereof. In addition, triangular valleys 34 are formed between the effective diameter portion 31 and the inner triangular triangle 32, between both triangular peaks 32, and between the outer triangular triangle 32 and the flat portion 33, respectively. Yes.

  The effective diameter portion 31 is a range through which effective light enters from the opening of the combined lens 1 and reaches the imaging surface 21a. The triangular mountain 32 and the triangular valley 34 are formed concentrically around the effective diameter portion 31 around the optical axis. The vertices of the two triangular peaks 32 are arranged in one plane perpendicular to the optical axis, as shown in FIG. Further, as shown in FIG. 1, a convex portion 13 a is provided on the inner peripheral side of the abutting portion 18 on the front surface of the edge portion of the optical lens 13, and the light shielding plate 16 includes the apex of the triangular mountain 32 and the optical lens 13. Are fixed by being sandwiched between the convex portions 13a.

  Further, the flat portion 33 is in contact with a similar flat portion provided on the front surface of the optical lens 13 to form the contact portion 18 shown in FIG. Further, the thickness of the triangular valley 34 of the optical lens 12 is formed substantially equal to that of the effective diameter portion 31 as shown in FIG. In this figure, two triangular peaks 32, 32 are provided, but one or more may be formed. This optical lens 12 corresponds to the lens of the present invention.

  Since it is formed as described above, the edge portion of the optical lens 12 has a portion corresponding to the flat surface portion 101a as in the optical lens 101 of the conventional combined lens 100 shown in FIG. There is nowhere. Therefore, the incident light L incident from outside the effective incident angle is not repeatedly reflected between the front surface and the rear surface of the optical lens 12 and cannot pass through the contact portion 18. That is, the incident light L passes through the convex portion 12a and is absorbed by the light shielding plate 16 as shown in FIG. Thus, there is no incident light that becomes VG as in the incident light L1 shown in FIG. 3, and VG is prevented.

  Further, in the optical lens 12, the triangular peaks 32, 32 provided on the rear surface of the edge portion are wavy, and the thickness outside the effective diameter portion 31 changes in the radial direction. That is, large continuous thick portions are not formed. And since the thickness of the triangular valley 34 is formed substantially equal to the effective diameter part 31, sink marks are prevented and the moldability is good.

  Further, since the apex positions of the triangular peaks 32 are aligned, the light shielding plate 16 can be appropriately sandwiched between these and the convex portion 13a of the optical lens 13 as shown in FIG. Further, since the optical lens 12 and the optical lens 13 are in direct contact with each other by the contact portion 18, the distance between these lenses in the optical axis direction is accurately positioned. The convex portion 13a of the optical lens 13 is not necessarily formed on the entire circumference as long as the light shielding plate 16 is appropriately supported.

  As described in detail above, according to the assembled lens 1 of this embodiment, the optical lens 12 and the optical lens 13 are positioned in direct contact with each other at the contact portion 18. A convex portion 12 a is formed on the rear surface on the inner peripheral side from the portion 18. Therefore, incident light outside the effective incident angle is repeatedly reflected between the front surface and the rear surface of the edge portion of the optical lens 12 and does not pass through the contact portion 18. Therefore, even if the optical lenses 12 and 13 are positioned in direct contact with each other, the moldability is kept good and the light incident on the outer peripheral side from the effective diameter is prevented from reaching the image sensor 21 and becoming VG. ing.

In addition, this form is only a mere illustration and does not limit this invention at all. Therefore, the present invention can naturally be improved and modified in various ways without departing from the gist thereof.
For example, in this embodiment, the lens of the present invention is applied to the second optical lens 12 from the subject side, but the present invention is not limited to this. Any lens can be applied as long as it is positioned in direct contact with the adjacent lens.
Further, for example, in the present embodiment, the triangular mountain 32 is formed on the rear surface of the optical lens 12, but the same effect can be obtained by forming a wave shape on the front surface as long as it does not interfere with the attachment to the lens barrel 15. can get.
Further, for example, in the above embodiment, the triangular mountain 32 is illustrated as an annular convex portion formed on the optical lens 12. Alternatively, it may be a trapezoidal mountain with a slightly collapsed vertex, or a mountain with a curved cross section instead of a straight line. However, in the trapezoidal mountain, there is a risk that the apex that becomes a flat surface may reflect light in an unfavorable direction like the conventional flat part, and the slope with a curved cross section scatters light, so both are somewhat inferior. . Therefore, the triangular mountain 32 is optimal as the annular convex portion.
Further, for example, the shapes of the lenses 11 to 14 and the shapes of the lens barrel 15 and the locking frame 23 are only examples, and are not limited thereto.

It is sectional drawing which shows the group lens of this form. It is a perspective view which shows an optical lens. It is sectional drawing which shows the conventional group lens.

Explanation of symbols

1 lens group 12 optical lens (lens)
16 Shading plate (shading member)
31 Effective diameter part 32 Triangle mountain (annular uneven part, annular convex part)
33 plane part 34 triangular valley (annular uneven part, annular concave part)

Claims (4)

An effective diameter portion,
An annular concavo-convex portion which is located adjacent to the outer periphery of one surface of the effective diameter portion and has an annular concavo-convex shape;
And a flat surface portion located outside the annular uneven portion on the surface of the annular uneven portion. The lens according to claim 1,
The lens having at least one pair of an annular convex portion and an annular concave portion provided on the annular concave and convex portion. In a combination lens composed of two or more lenses,
At least one lens
An effective diameter portion,
An annular concavo-convex portion which is located adjacent to the outer periphery of one surface of the effective diameter portion and has an annular concavo-convex shape;
A plane portion that is located outside the annular uneven portion on the surface of the annular uneven portion side and that is in direct contact with other lenses;
A combined lens, wherein a ring-shaped light shielding member is sandwiched between the lens and a lens that is in direct contact with the planar portion of the lens. In the combination lens according to claim 3,
The combined lens according to claim 1, wherein at least one pair of an annular convex portion and an annular concave portion is provided on the annular uneven portion.

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