JP2008145929A - Lens unit, imaging apparatus, and method for manufacturing lens unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens unit which is easy to automate assembly by surely and highly accurately inserting and fitting a compact imaging lens into a lens frame, without using a special jig. <P>SOLUTION: The lens unit has an imaging lens composed of a plurality of lenses and the lens frame holding the imaging lens by the inwall thereof. The outer circumferential wall of a rear lens located nearest to an imaging surface by the imaging lens is nearly in contact with the inner circumferential wall of the lens frame along the whole circumference. A path communicating the opening of the lens frame through which object light enters and the end surface on an object side of the rear lens is provided in a part of the outer surface in contact with the lens frame, of the front lens of the imaging lens except the rear lens. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a lens unit in which a small imaging lens can be easily and reliably inserted into a lens frame, an imaging device including the lens unit, and a method for manufacturing a lens unit in which the imaging lens is inserted into the lens frame.

  Smaller and thinner imaging devices than ever before are now mounted on portable terminals, which are small and thin electronic devices such as mobile phones and PDAs (Personal Digital Assistants). Information can also be transmitted between each other.

  As an image pickup element used in these image pickup apparatuses, a solid-state image pickup element such as a CCD (Charge Coupled Device) type image sensor or a CMOS (Complementary Metal-Oxide Semiconductor) type image sensor is used.

  These image pickup apparatuses are provided with a small lens unit. The lens unit is mainly composed of a small image pickup lens and a lens frame, and the image pickup lens is held by an inner wall of the lens frame.

  An example of such a lens unit is shown in FIG. In FIG. 8, a lens frame 52 holds an imaging lens 51 composed of four single lenses on an inner wall. In order to insert the imaging lens 51 into the lens frame 52 in the manufacturing process, first, the imaging lens 51 is lightly inserted into the lens frame 52 from the rear of the lens frame 52, that is, from the imaging surface side. Further, the imaging lens 51 is pressed from behind using the jig 55 so that the front surface of the imaging lens 51 comes into contact with the inner surface of the lens frame 52 so that the imaging lens 51 is accurately inserted into the lens frame 52. To.

Also, an imaging lens (imaging optical system), a cam member having a cam surface that contacts the rear part of the imaging lens, a base member that holds the cam member, a lens frame (outer frame member) that holds the imaging lens, and engages with the imaging lens An imaging apparatus is known in which a rotating member that rotates is mounted in the same direction and assembled (see Patent Document 1).
JP-A-2005-117376

  In the lens unit shown in FIG. 8, the final surface of the imaging lens 51 is pressed by the jig 55, but the portion where the jig 55 comes into contact is wrinkled. Therefore, the portion pressed by the jig 55 is an optical path through which subject light passes on the final surface of the imaging lens 51, that is, a portion outside the effective diameter. Since the outer end face of the imaging lens 51 shown in FIG. 8 is very small, it is not suitable for pressing with the jig 55 and it is desirable to make the end face larger. However, since this end face is an optically unnecessary part, if it is easy to press with the jig 55, the outer diameter of the imaging lens 51 becomes uselessly larger and the lens unit becomes larger, and the imaging apparatus is downsized. Become an obstacle.

In addition, an imaging device used for a mobile phone or the like is a very small device having a volume of 1 cm ² or less, requires very delicate handling, and has a high assembly cost. On the other hand, since the lens unit shown in FIG. 8 uses the jig 55, it is difficult to automate assembly, and cost reduction cannot be expected.

  On the other hand, in Patent Document 1, since many members are placed in the same direction, automation is possible, and the imaging lens placed in the subsequent process is pressed against the cam member by a spring. The optical accuracy of is guaranteed. However, in the lens unit having the configuration shown in FIG. 8, since there is no spring, simply placing the imaging lens 51 inside the lens frame 52 does not guarantee optical accuracy. It cannot be applied to the lens unit having the configuration of 8.

  The present invention has been made in view of such a problem, and a lens unit that allows a small imaging lens to be securely and accurately inserted into a lens frame without using a special jig, and facilitates assembly automation, and the lens unit. It is an object of the present invention to propose a small-sized imaging device including a lens unit and a method for manufacturing a lens unit.

The object is achieved by the invention described below.
1. An imaging lens composed of a plurality of lenses;
A lens frame that holds the imaging lens on the inner wall,
The outer peripheral wall of the rear lens located closest to the imaging surface by the imaging lens is substantially in contact with the inner peripheral wall of the lens frame along the entire circumference,
The flow path that connects the opening of the lens frame for allowing the subject light to enter and the end surface on the object side of the rear lens is in contact with the lens frame of the front lens of the imaging lens excluding the rear lens. A lens unit provided on a part of the surface.
2. 2. The lens unit according to 1, wherein the flow path is formed by a notch or a long groove provided in the front lens.
3. The lens unit according to 1 or 2, wherein the flow passage is provided in a light shielding member disposed between the lenses.
4). An imaging lens composed of a plurality of lenses;
A lens frame that holds the imaging lens on the inner wall,
The outer peripheral wall of the rear lens located closest to the imaging surface by the imaging lens is substantially in contact with the inner peripheral wall of the lens frame along the entire circumference,
An inner wall of the lens frame, in which a flow path communicating with an opening of the lens frame for allowing subject light to enter and an end surface on the object side of the rear lens is in contact with the front lens of the imaging lens excluding the rear lens A lens unit provided on a part of the lens unit.
5. 5. The lens unit according to 4, wherein the flow passage is formed by a long groove provided in the lens frame.
6). The lens unit according to any one of 1 to 5, wherein the flow passages are equally arranged in a circumferential direction.
7). The lens unit according to any one of claims 1 to 6, wherein a flow hole communicating with the flow passage is formed around the opening of the lens frame.
8). 8. The lens unit according to 7, wherein an embedded member for embedding the flow hole is provided.
9. An imaging apparatus comprising the lens unit according to any one of 9.1 to 8.
10. An imaging lens composed of a plurality of lenses;
A lens frame that holds the imaging lens on the inner wall,
The outer peripheral wall of the rear lens located closest to the imaging surface by the imaging lens is substantially in contact with the inner peripheral wall of the lens frame along the entire circumference,
The flow path that connects the opening of the lens frame for allowing the subject light to enter and the end surface on the object side of the rear lens is in contact with the lens frame of the front lens of the imaging lens excluding the rear lens. A method of manufacturing a lens unit provided on a part of a surface,
Inserting the imaging lens into the lens frame from the imaging plane side;
Sucking the rear lens through the flow path from the opening of the lens frame;
A method for manufacturing a lens unit, comprising:
11. An imaging lens composed of a plurality of lenses;
A lens frame that holds the imaging lens on the inner wall,
The outer peripheral wall of the rear lens located closest to the imaging surface by the imaging lens is substantially in contact with the inner peripheral wall of the lens frame along the entire circumference.
An inner wall of the lens frame, in which a flow path communicating with an opening of the lens frame for allowing subject light to enter and an end surface on the object side of the rear lens is in contact with the front lens of the imaging lens excluding the rear lens A method of manufacturing a lens unit provided in a part of
Inserting the imaging lens into the lens frame from the imaging plane side;
Sucking the rear lens through the flow path from the opening of the lens frame;
A method for manufacturing a lens unit, comprising:
12 The method of manufacturing a lens unit according to 10 or 11, further comprising a step of bonding the rear lens to the lens frame with an adhesive.

  According to the lens unit, the imaging device, and the manufacturing method of the lens unit of the present invention, it is possible to reduce the size of the lens and the accompanying compact imaging device, and the imaging lens can be attached to the lens frame without using a special jig. Therefore, the assembly can be automated easily.

  An embodiment of a lens unit of the present invention and an image pickup apparatus having the lens unit will be described in detail with reference to the drawings.

  First, an example of a mobile phone as a mobile terminal equipped with an imaging device will be described with reference to the external view of FIG. 1A is a view of the folded mobile phone when viewed from the inside, and FIG. 1B is a view of the folded mobile phone when viewed from the outside.

  In FIG. 1, in the mobile phone T, an upper casing 71 as a case having display screens D <b> 1 and D <b> 2 and a lower casing 72 having an operation button B are connected via a hinge 73. The imaging device is built under the display screen D <b> 2 in the upper casing 71, and the imaging lens 51 is exposed on the outer surface of the upper casing 71.

  Note that the position of the imaging device may be disposed above or on the side of the display screen D2 in the upper casing 71. Further, the mobile phone T is not limited to a folding type.

  Next, the lens unit will be described with reference to FIGS. 2 is a cross-sectional view of the lens unit, and FIG. 3 is a perspective view of the imaging lens.

  In FIG. 2, the lens unit includes an imaging lens 11 and a lens frame 12 that holds the imaging lens 11 on the inner wall.

  The imaging lens 11 includes four single lenses of a first lens 111, a second lens 112, a third lens 113, and a fourth lens 114 in order from the subject side. Further, a light shielding plate 13 is provided between the first lens 111 and the second lens 112, a light shielding plate 14 is provided between the second lens 112 and the third lens 113, and the third lens 113 and the fourth lens 114 are provided. A light shielding plate 15 is disposed between them. The light shielding plates 13, 14, 15 (light shielding members) are for preventing unnecessary light from reaching the imaging plane P and causing flares and ghosts.

  The imaging lens 11 is inserted into the lens frame 12 from the image plane P side and is held on the inner wall of the lens frame 12.

  Here, as shown in FIG. 3, the three lenses (front lens) of the first lens 111, the second lens 112, and the third lens 113 excluding the fourth lens 114 (rear lens) located closest to the imaging plane P are used. Notches 111a, 112a, and 113a are formed in part of the outer surface that contacts the lens frame 11 in FIG. In the first lens 111, notches 111a are provided on the end surface and the outer peripheral surface on the object side, and in the second lens 112 and the third lens 113, notches 112a and 113a are provided on the outer peripheral surface. And three notches 111a, 112a, and 113a are equally arranged in the circumferential direction. The light shielding plates 13 and 15 are also provided with similar notches.

  In addition, although three of these notches are desirable, two or three or more may be sufficient depending on circumstances. However, it is desirable to arrange them equally in the circumferential direction.

  Further, the outer peripheral wall of the fourth lens 114 is substantially in contact with the inner peripheral wall of the lens frame 12 along the entire circumference, and is not provided with a notch.

  Next, a procedure for assembling the lens unit by inserting the imaging lens 11 configured as described above into the lens frame 12 will be described.

  First, the first lens 111, the second lens 112, the third lens 113 are notched 111 a, 112 a, 113 a, and the light shielding plates 13, 15 are aligned with the direction of the optical axis O, and the first lens 111 in order. The light shielding plate 13, the second lens 112, the light shielding plate 14, the third lens 113, the light shielding plate 15, and the fourth lens 114 are lightly inserted into the lens frame 12 from the imaging surface P side.

  Subsequently, the vacuum pump (not shown) is operated, and the imaging lens 11 is sucked from the opening 12a of the lens frame 12 for entering the subject light. At this time, an air flow path is formed between the opening 12a and the end surface 114a on the subject side of the fourth lens 114 by the cutouts of the cutouts 111a, 112a, 113a and the light shielding plates 13, 15, and the opening is opened. The portion 12a and the end surface 114a communicate with each other.

  Therefore, the end surface 114a of the fourth lens 114 is sucked toward the subject by this suction, and the first lens 111, the light shielding plate 13, the second lens 112, the light shielding plate 14, and the third lens pressed by the fourth lens 114 thereby. 113, the light shielding plate 15 moves to the subject side, and the front end 111a of the first lens 111 contacts the inner wall 12b of the lens frame 12.

  In this way, the imaging lens 11 can be automatically and reliably and accurately inserted into the lens frame 12 by suction with a vacuum pump without using the jig 55 for pressing the imaging lens 11 as shown in FIG. Worn. For this reason, the end surface on the imaging surface side of the fourth lens 114 may be small.

  Further, by sucking in this way, dust adhering to the surface of the first lens 111 is removed, and at the same time, dust between the lenses is also removed. Accordingly, the lens unit may be cleaned only by the surface on the image plane P side of the fourth lens 114, and the number of cleaning steps may be reduced.

  After the imaging lens 11 is inserted into the lens frame 12, the fourth lens 114 is bonded to the lens frame 12 with the adhesive S to fix the imaging lens 11. As the adhesive, anaerobic curable, primer curable, ultraviolet curable adhesive and the like can be used.

  In order to form an air flow path in the imaging lens, the flow path is not necessarily limited to the notch as shown in FIG. For example, as in the imaging lens 21 shown in the perspective view of FIG. 4, long grooves parallel to the optical axis O are formed in the first lens 211, the second lens 212, and the third lens 213 except the fourth lens 214 through the air flow path. 211a, 212a, and 213a may be provided.

  Furthermore, the suction position is not necessarily limited to the opening of the lens frame for allowing the subject light to enter, and a plurality of circulation holes 32c are provided around the opening 32a of the lens frame 32 as shown in FIG. May be provided and sucked from the respective circulation holes 32c. In addition, it is necessary to arrange | position the flow hole 32c and the flow path formed in the imaging lens 31 facing each other, and if there are three flow paths, the flow holes 32c are also three. Thus, the end surface 314a of the fourth lens 314 can be sucked more directly, and the suction force may be weak. However, after the imaging lens 31 is inserted into the lens frame 32, it is necessary to bury the flow hole 32c with a predetermined burying member so that dust does not enter.

  In addition, the air flow path may be formed in the lens frame instead of being formed in the imaging lens. This is shown in FIGS. 6 is a cross-sectional view of the lens unit, and FIG. 7 is a cross-sectional view taken along line AA in FIG.

  In both figures, three long grooves (flow passages) 42d where the opening 42a of the lens frame 42 for entering the subject light and the end surface 414a on the subject side of the fourth lens 414 in the imaging lens 41 communicate with each other are imaged. The first lens 411, the second lens 412, and the third lens 413 except for the fourth lens 414 in the lens 41 are provided on a part of the inner wall of the lens frame 42 that contacts the lens frame 42.

  Therefore, if suction is performed from the opening 42a as described above, the end surface 414a of the fourth lens 414 is suctioned, and the lens unit 41 is securely inserted into the lens frame 42.

  In the above embodiment, the fourth lenses 114, 214, 314, and 414 as the rear lenses are one single lens. However, when the fourth lens is bonded to the third lens, The three lenses also become the rear lenses, and the object side end surface of the third lens is sucked through the flow path.

It is an external view of a mobile phone. It is sectional drawing of a lens unit. It is a perspective view of an imaging lens. It is a perspective view of an imaging lens of a different form. It is sectional drawing of the lens unit of a different form. Furthermore, it is sectional drawing of the lens unit of a different form. It is AA sectional drawing in FIG. It is sectional drawing of the conventional lens unit.

Explanation of symbols

11, 21, 31, 41, 51 Imaging lens 111, 211, 411 First lens 111a, 112a, 113a Notch 112, 212, 412 Second lens 113, 213, 413 Third lens 114, 214, 314, 414 First Four lenses 114a, 314a, 414a End face 12, 52, 42 Mirror frame 12a, 42a Opening part 13, 14, 15 Light-shielding plate 211a, 212a, 213a, 42d Long groove 32c Flow hole P Imaging surface O Optical axis S Adhesive

Claims (12)

An imaging lens composed of a plurality of lenses;
A lens frame that holds the imaging lens on the inner wall,
The outer peripheral wall of the rear lens located closest to the imaging surface by the imaging lens is substantially in contact with the inner peripheral wall of the lens frame along the entire circumference.
The flow path connecting the opening of the lens frame for entering the subject light and the subject side end surface of the rear lens is in contact with the lens frame of the front lens of the imaging lens except for the rear lens. A lens unit provided on a part of the surface. The lens unit according to claim 1, wherein the flow path is formed by a notch or a long groove provided in the front lens. The lens unit according to claim 1, wherein the flow path is provided in a light shielding member disposed between the lenses. An imaging lens composed of a plurality of lenses;
A lens frame that holds the imaging lens on the inner wall,
The outer peripheral wall of the rear lens located closest to the imaging surface by the imaging lens is substantially in contact with the inner peripheral wall of the lens frame along the entire circumference.
An inner wall of the lens frame on which a flow path communicating with an opening of the lens frame for allowing subject light to enter and an end surface on the object side of the rear lens abuts the front lens of the imaging lens excluding the rear lens A lens unit provided on a part of the lens unit. The lens unit according to claim 4, wherein the flow path is formed by a long groove provided in the lens frame. The lens unit according to claim 1, wherein the flow passages are equally arranged in a circumferential direction. The lens unit according to claim 1, wherein a flow hole communicating with the flow passage is formed around the opening of the lens frame. The lens unit according to claim 7, further comprising an embedded member that embeds the flow hole. An imaging apparatus comprising the lens unit according to claim 1. An imaging lens composed of a plurality of lenses;
A lens frame that holds the imaging lens on the inner wall,
The outer peripheral wall of the rear lens located closest to the imaging surface by the imaging lens is substantially in contact with the inner peripheral wall of the lens frame along the entire circumference.
The flow path connecting the opening of the lens frame for entering the subject light and the subject side end surface of the rear lens is in contact with the lens frame of the front lens of the imaging lens except for the rear lens. A method of manufacturing a lens unit provided on a part of a surface,
Inserting the imaging lens into the lens frame from the imaging plane side;
Sucking the rear lens through the flow path from the opening of the lens frame;
A method for manufacturing a lens unit, comprising: An imaging lens composed of a plurality of lenses;
A lens frame that holds the imaging lens on the inner wall,
The outer peripheral wall of the rear lens located closest to the imaging surface by the imaging lens is substantially in contact with the inner peripheral wall of the lens frame along the entire circumference.
An inner wall of the lens frame, in which a flow path communicating with an opening of the lens frame for allowing subject light to enter and an end surface on the object side of the rear lens is in contact with the front lens of the imaging lens excluding the rear lens A method of manufacturing a lens unit provided in a part of
Inserting the imaging lens into the lens frame from the imaging plane side;
Sucking the rear lens through the flow path from the opening of the lens frame;
A method for manufacturing a lens unit, comprising: The method of manufacturing a lens unit according to claim 10, further comprising a step of bonding the rear lens to the lens frame with an adhesive.

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