JP2005338218A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens unit miniaturized by reducing its thickness in an optical axis direction. <P>SOLUTION: In the lens unit 1 constituted of a photographic lens 2 where lens parts 32 and 34 are respectively formed in the centers of respective end faces on a subject side and an image formation surface side, a barrel-shaped lens holder 3 equipped with the photographic lens 2 inside, and a thin-plate type diaphragm 8 having a through-hole 83 in the center, the diaphragm 8 is formed so that its part nearer to an outer circumference than a 1st annular part 81 abutting on the photographic lens 2 may be bent to the image formation surface side, and its 2nd annular part 82 is fixed at the edge of the lens holder 3 on the subject side by heating and pressing a projection 72 in such a state. Since the deformed projection 72 is made to retreat to the image formation surface side, the lens unit is miniaturized in the optical axis direction. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an imaging apparatus, and more particularly, to an imaging apparatus mounted on a digital imaging apparatus such as a digital camera or a camera-equipped mobile phone.

  A lens unit 11 mounted on a digital imaging device such as a conventional digital camera or camera-equipped mobile phone is applied to an imaging device 10 as shown in FIG. 8 and includes a photographing lens 3 and a lens holder 2.

  The photographic lens 3 is a so-called front diaphragm type lens designed to dispose a stop on the subject side, and has an annular flat surface portion 31 on the end surface on the subject side, and a convex lens portion 32 formed at the center. In addition, an annular flat surface portion 33 is formed on the end surface on the imaging surface side, and a concave lens portion 34 is formed in the center.

  The lens holder 2 is made of resin, and includes a cylindrical portion 21 provided with the photographing lens 3 therein, a tapered portion 22 that decreases in diameter from the subject-side end of the cylindrical portion 21 toward the subject, and the tapered portion 22. An annular portion 24 that extends from the tip toward the inner periphery and has a through hole 23 in the center is integrally formed. The through hole 23 of the annular portion 24 has a tapered diameter that decreases from each of the subject side and the imaging surface side, and protrudes in a wedge shape toward the inner periphery at a substantially intermediate position in the optical axis direction of the through hole 23. 75 is further provided. The smallest diameter portion of the through hole 23, that is, the inner diameter of the tip of the projecting portion 75 is slightly smaller than the lens portion 32 on the subject side of the photographing lens 3, and functions as a diaphragm of the photographing lens 3. A male screw 25 is formed on the outer peripheral surface of the lens holder 2 on the image forming surface side.

  In such a lens unit 11, the plane portion 31 on the subject side is in contact with the end surface 26 on the imaging surface side in the annular portion 24 of the lens holder 2, and the planar portion 33 on the imaging surface side is an annular pressing member. The lens holder 2 is fixed by being pressed and adhered by 35.

  The imaging apparatus 10 to which the lens unit 11 having the above configuration is applied includes an imaging element package 4 and a lens barrel 5 in addition to the lens unit 2.

  The image pickup device package 4 is attached to a substrate 12 and has an image pickup device (not shown) made of CCD, CMOS, or the like housed in a resin casing. A surface (surface opposite to the substrate 12 side) 41 of the image pickup device package 4 is opened at a position facing the image pickup device (not shown), and a light-transmitting property such as an infrared cut filter is formed so as to close the opening. Member 42 is affixed.

  In the lens barrel 5, a rectangular tube portion 51 that surrounds the image pickup device package 4 and is fixed to the substrate 12, and a cylindrical portion 52 on which the lens unit 1 is mounted are integrally formed. A female screw 53 for screwing the lens unit 1 is formed on the inner periphery of the cylindrical portion 52.

  In the imaging apparatus 10 having the above configuration, the rectangular tube portion 51 of the lens barrel 5 surrounds the imaging device package 4 and is put on and bonded to the surface 41 of the imaging device package 4, and the lens unit 11 is attached to the cylindrical portion 52 of the lens barrel 5. Are screwed together.

  However, in such a lens unit 11, since the lens holder 2 is integrally formed with the annular portion 24 as a diaphragm and a resin, the annular portion 24 requires a predetermined thickness from the viewpoint of securing rigidity. Hinders downsizing. Accordingly, the following lens unit has been proposed.

  As shown in FIG. 9, in the lens unit 13, an aperture 6 as a separate member is installed at the subject-side end of the lens holder 2 instead of the integrally formed annular portion 24. The diaphragm 6 is formed in a thin plate shape that is sufficiently thin with respect to the thickness of the photographic lens 3, and a circular through hole 61 is formed in the center with the same diameter in the optical axis direction. This diaphragm 6 is inserted from above into a mounting recess 28 formed on the subject side of the lens holder 2 and is in close contact with the flat surface portion 31 excluding the lens portion 32 at the center of the photographic lens 3. It is fixed by. At this time, the upper surface 62 of the diaphragm 6 and the upper end surface 29 of the lens holder 2 are substantially in the same plane. Note that a flange 71 for positioning the photographing lens 3 is formed at the end of the lens holder 2 on the imaging surface side (see, for example, Patent Document 1).

Alternatively, as shown in FIG. 10, ultrasonic energy or the like is applied to the projection 72 (dotted line in the drawing) on the subject side edge of the lens holder 2 with the thin plate-like diaphragm 6 similar to the above installed. It is conceivable that the diaphragm is fixed by heating, softening and crushing (hereinafter, this construction method is referred to as heat caulking) (see, for example, Patent Document 2).
JP 2003-84184 A JP 2003-333437 A

  However, in the lens unit as described above, in the case of fixing with an adhesive, it takes a long time for the adhesive to cure, and with the instantaneous adhesive, the surface of the photographing lens 3 may become white and cloudy. In addition, heat caulking is excellent in that the working time can be shortened, but since the deformed portion due to heating protrudes toward the subject side, downsizing of the imaging device 10 is hindered by the protrusion. Further, since the through hole 61 of the diaphragm 6 has the same diameter in the optical axis direction, there is a concern that the photographing light is irregularly reflected on the inner wall surface exposed in the through hole 61 and adversely affects the photographed image.

  A lens unit according to the present invention includes a photographic lens, a cylindrical lens holder that includes the photographic lens therein and includes a positioning portion that comes into contact with the photographic lens, a through hole in the center, and a subject side of the photographic lens A holding unit made of a highly rigid material having a thickness that is sufficiently thin with respect to the entire length in the optical axis direction of the photographic lens. The portion closer to the outer periphery than the portion in contact with the photographing lens is bent toward the image plane.

  According to this configuration, since the pressing plate is made of a highly rigid material such as metal, the pressing plate can be formed thin, and the outer peripheral portion of the pressing plate is bent toward the imaging surface side. Therefore, the fixed position with respect to the lens holder can be retracted closer to the image plane than the end surface on the subject side of the photographing lens. Therefore, a space allowing a deformed portion due to heat caulking is created by this retraction, and the lens unit can be formed without increasing the size of the lens holder in the optical axis direction even by heat caulking.

  The number of photographic lenses is not limited. Therefore, in a plurality of cases, the end surface on the subject side of the photographing lens means the end surface on the subject side of the lens closest to the subject side, and the end surface on the imaging surface side of the photographing lens is closest to the imaging surface side. An end surface on the image plane side of the lens. Further, the shape of each lens portion on the subject side and the imaging surface side is not limited and may be a convex lens or a concave lens.

  In the lens unit, it is preferable that at least a part of the inner wall diameter of the through hole of the pressing plate is not the same diameter from the subject side to the imaging plane side. According to this configuration, exposure of the inner wall of the through hole is reduced, and irregular reflection of shooting light at the exposed portion can be reduced, and a clear shot image can be obtained.

  In the lens unit, it is preferable that the inner wall diameter of the through hole of the pressing plate is large on the imaging surface side. According to this configuration, it is possible to eliminate interference between the through hole of the pressing plate and the vicinity of the base end portion of the lens portion on the subject side without complicated bending.

  In the lens unit, it is preferable that the vicinity of the through hole of the pressing plate protrudes toward the subject. According to this configuration, for example, even when the lens portion on the subject side of the photographing lens is a convex lens and protrudes from the end surface on the subject side, the vicinity of the through hole of the holding plate is near the base end portion of the lens portion on the subject side. There will be no interference.

  In the lens unit, it is preferable that the pressing plate is a diaphragm of a photographing lens. According to this configuration, since the pressing plate functions as a diaphragm, it is possible to limit extra incident light other than the subject and obtain a clearer captured image. In order to cause the pressing plate to function as a stop, the diameter of the minimum diameter portion of the through hole of the pressing plate is set slightly smaller than the diameter of the lens portion on the subject side of the photographing lens.

  As is clear from the above description, in the lens unit of the present invention, the outer peripheral portion of the holding plate is bent toward the imaging surface side, so the fixing position with the lens holder is from the end surface on the subject side of the photographic lens. Can also be retracted to the image plane side. Therefore, a space allowing a deformed portion due to heat caulking is created by this retraction, and the lens unit can be formed without increasing the size of the lens holder in the optical axis direction even by heat caulking.

  Also, since the inner wall diameter of the through hole of the holding plate is not at least partially the same from the subject side to the imaging surface side, the inner wall of the through hole is less exposed, and the irregular reflection of the shooting light at this exposed part is reduced and clear. It is possible to obtain a captured image.

(Embodiment 1)
A first embodiment of a lens unit according to the present invention will be described with reference to FIGS. 1 and 2 by applying this lens unit to an imaging apparatus. However, the same parts as those in the conventional example will be described with the same reference numerals. The lens unit 1 includes a photographing lens 3, a lens holder 2, and a diaphragm 8.

  The photographic lens 3 is a so-called front diaphragm type lens designed to dispose a stop on the subject side, and has an annular flat surface portion 31 formed on an end surface on the subject side, and a convex lens portion in the center. 32 is formed, an annular flat surface portion 33 is formed on the end surface on the imaging surface side, and a concave lens portion 34 is formed in the center. Both the plane part 31 on the subject side and the plane part 33 on the imaging plane side are formed perpendicular to the optical axis. In addition, the subject-side plane portion 31 is formed so as to be positioned substantially on the same plane as the top portion 35 of the subject-side lens portion 32, and the lens portion 32 does not protrude toward the subject side. The taking lens 3 can be divided into a plurality of parts as required, and glass or the like can be used as a material.

  The lens holder 2 is a cylindrical member made of a resin colored black with little irregular reflection of light, and abuts against a cylindrical portion 21 containing the photographing lens 3 and a plane portion 33 on the imaging surface side of the photographing lens 3. A flange 71 extending toward the inner peripheral side is integrally formed. The collar portion 71 is a positioning portion described in claims, and an end surface 73 on the subject side is formed perpendicular to the optical axis. At the edge of the lens holder 2 on the subject side, a step portion 74 for disposing the diaphragm 8 is provided at a portion near the inner periphery, and a portion closer to the outer periphery than the step portion 74 protrudes toward the subject side. A projection 72 (dotted line in the figure) is provided. A male screw 25 is formed on the image forming surface side of the outer peripheral surface of the lens holder 2.

  The diaphragm 8 is made of a highly rigid member plate such as a metal, and has a first annular portion 81 having a through hole 83 in the center, and is bent from the outer periphery of the first annular portion 81 toward the image plane to expand in a tapered shape. The taper portion 84 is formed of a diameter and a second annular portion 82 extending from the outer periphery of the taper portion 84 toward the outer periphery. The diaphragm 8 has a sufficiently thin thickness of about 0.05 mm with respect to the total length of the photographing lens 3 in the optical axis direction of about 3.9 mm. The diameter a of the through hole 83 of the first annular portion 81 is set slightly smaller than the diameter b of the lens portion 32 on the subject side of the photographing lens 3. The entire surface of the diaphragm 8 is painted black to prevent irregular reflection of light.

  The lens unit 1 having the above configuration is assembled as follows.

  First, the photographing lens 3 is incorporated into the lens holder 2, and the flat surface portion 33 on the imaging surface side of the photographing lens 3 is brought into contact with the subject-side end surface 73 of the collar portion 71 of the lens holder 2. Next, the diaphragm 8 is disposed on the subject side step 74 of the lens holder 2 from the subject side. At this time, the imaging plane side of the first annular portion 81 of the diaphragm 8 is in close contact with the plane portion 31 on the subject side of the photographing lens 3. In this state, the diaphragm 8 is fixed to the lens holder 2 by applying ultrasonic energy or the like to the projection 72 (two-dot chain line in the figure) on the subject side of the lens holder 2 to soften it by heating and crushing it. Yes (heat caulking). In this state, the subject-side end surface 73 of the collar portion 71 of the lens holder 2 and the imaging portion-side flat surface portion 33 of the photographing lens 3 are formed perpendicular to the optical axis. And the optical axis of the lens holder 2 coincide with each other.

  In the lens unit 1 configured as described above, since the diaphragm 8 is made of a highly rigid material such as metal, the diaphragm 8 can be formed thin, and the outer peripheral portion of the diaphragm 8 is smaller than the first annular portion 81. Since it is bent toward the imaging plane side, the fixed position with respect to the lens holder 2 can be retracted to the imaging plane side from the top portion 35 of the photographing lens 3. Accordingly, a space allowing the deformed portion by heat caulking is provided by this retracted amount, and the lens unit 1 can be formed without increasing the size of the lens holder 2 in the optical axis direction even by heat caulking.

  The lens unit 1 having the above configuration is applied to, for example, the following imaging device 10. The imaging device 10 includes an imaging element 4 and a lens barrel 5 in addition to the lens unit 1 described above.

  The image pickup device package 4 is attached to a substrate 12 and has an image pickup device (not shown) made of CCD, CMOS, or the like housed in a resin casing. A surface (surface opposite to the substrate 12 side) 41 of the image pickup device package 4 is opened at a position facing the image pickup device (not shown), and a light-transmitting property such as an infrared cut filter is formed so as to close the opening. Member 42 is affixed.

  In the lens barrel 5, a rectangular tube portion 51 that surrounds the image pickup device package 4 and is fixed to the substrate 12, and a cylindrical portion 52 on which the lens unit 1 is mounted are integrally formed. A female screw 53 for screwing the lens unit 1 is formed on the inner periphery of the cylindrical portion 52.

  In the imaging device 10 having the above-described configuration, the rectangular tube portion 51 of the lens barrel 5 surrounds the image sensor package 4 attached to the substrate 12 and is placed on and bonded to the surface 41 of the image sensor package 4. The lens unit 1 is screwed into the cylindrical portion 52. In such a state, the photographing light incident from the subject side of the lens unit 1 forms an image on an image sensor (not shown) in the image sensor package 4. Then, by rotating the lens unit 1, the lens unit 1 moves in the optical axis direction, and focus adjustment is performed.

(Embodiment 2)
The second embodiment will be described with reference to FIG. In the second embodiment, in the vicinity of the through hole 83 of the first annular portion 81 of the diaphragm 8, the object side and the imaging surface side are cut by half etching or the like to form stepped portions 87 and 88, respectively. According to the second embodiment, the exposure of the wall surface 86 at the minimum diameter portion of the through hole 83 is reduced, and irregular reflection of the photographing light at the exposed portion can be reduced, and a clear photographed image can be obtained. Other configurations are the same as those in the first embodiment.

(Embodiment 3)
A third embodiment will be described with reference to FIG. In the third embodiment, the object-side plane part 31 is located on the same plane as the base end part 36 of the lens part 32, and the object-side lens part 32 protrudes toward the object side from the plane part 31. It becomes the shape to do. In this case, if the diameter of the through hole 83 of the diaphragm 8 is set smaller than the diameter of the lens portion 32, the vicinity of the through hole 83 of the diaphragm 8 interferes with the vicinity of the base end portion 36 of the lens portion 32 (in the drawing). dotted line). Therefore, the vicinity of the through hole 83 of the diaphragm 8 is bent toward the subject side to prevent such interference. Other configurations are the same as those in the first embodiment.

(Embodiment 4)
The fourth embodiment will be described with reference to FIG. In the fourth embodiment, the same photographing lens 3 as that in the third embodiment is applied, and the stepped portion 89 is formed by cutting the imaging surface side in the vicinity of the through hole 83 of the diaphragm 8 by half etching or the like. The vicinity of the through hole 83 does not interfere with the vicinity of the base end portion 36 of the lens portion 32. Other configurations are the same as those in the first embodiment. In this case, interference between the through hole 83 of the diaphragm 8 and the vicinity of the proximal end portion 36 of the lens portion 32 can be eliminated without complicated bending. Further, since the exposure of the wall surface 86 in the through hole 83 is reduced, the same effect as in the second embodiment can be expected.

  In addition, this invention is not limited to the above-mentioned embodiment, It can apply also to embodiment described below.

(Other examples)
(1) In order to reduce the exposure of the wall surface 86 in the through hole 83 of the aperture 8, the following may be performed in addition to the above embodiments. That is, as shown in FIG. 6, the diameter of the through hole 83 of the diaphragm 8 may be reduced in a taper shape from the subject side to the image plane side. Conversely, although not shown, the diameter may be increased in a tapered shape from the subject side to the image plane side of the stop. Alternatively, as shown in FIG. 7, the corners 91 and 92 on both the subject side and the imaging plane side in the vicinity of the through hole 83 may be cut. In this case, of course, only one of the subject side and the imaging plane side may be cut.

  (2) In each of the above embodiments, the minimum diameter of the through hole 83 of the diaphragm 8 may be formed to be equal to or larger than the diameter of the lens portion 32 on the subject side of the photographing lens 3 as necessary. In this case, the diaphragm 8 simply functions as a pressing plate for the photographic lens 3.

  (3) The diaphragm 8 is not necessarily made of metal, but it is preferably made of metal from the viewpoint that rigidity can be ensured even if it is made thin and bending is easy.

  The present invention can be suitably used for a lens unit that is mounted on today's digital imaging equipment, which is significantly downsized.

Sectional drawing of the imaging device to which the lens unit which concerns on Embodiment 1 of this invention is applied. FIG. The principal part expanded sectional view of the lens unit which concerns on Embodiment 2 of this invention. The principal part expanded sectional view of the lens unit which concerns on Embodiment 3 of this invention. The principal part expanded sectional view of the lens unit which concerns on Embodiment 4 of this invention. The principal part expanded sectional view of the lens unit which concerns on other embodiment of this invention. The principal part expanded sectional view of the lens unit which concerns on other embodiment of this invention. Cross-sectional view of an imaging apparatus to which a conventional lens unit is applied Sectional drawing of the imaging device which applied the conventional lens unit different from the above Sectional drawing of the imaging device which applied the conventional lens unit different from the above

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lens unit 2 Lens holder 3 Shooting lens 4 Image pick-up element package 5 Lens barrel 8 Diaphragm 10 Imaging device 12 Board | substrate 21 Cylindrical part 25 Male screw 31 Plane part 32 Lens part 33 Plane part 34 Lens part 35 Top part 36 Base end part 51 Square cylinder part 52 Cylindrical part 53 Female thread 71 Gutter part 72 Projection 74 Step part 81 First annular part 82 Second annular part 83 Through hole 84 Tapered part 86 Wall surface

Claims (5)

A photographing lens, a cylindrical lens holder that includes the photographing lens therein and includes a positioning portion that abuts the photographing lens, and has a through hole in the center and is in contact with the subject-side end surface of the photographing lens, and the outer periphery is the A lens unit composed of a highly rigid material with a thickness that is sufficiently thin with respect to the entire length of the photographic lens in the optical axis direction and fixed to the lens holder,
The holding plate is a lens unit in which a portion closer to the outer periphery than a portion contacting the photographing lens is bent toward the image plane.   2. The lens unit according to claim 1, wherein the inner wall diameter of the through hole of the pressing plate is not at least partially equal from the subject side to the image plane side.   The lens unit according to claim 1, wherein the inner wall diameter of the through hole of the pressing plate is large on the imaging plane side.   The lens unit according to claim 1, wherein the vicinity of the through hole of the pressing plate protrudes toward the subject side. The lens unit according to any one of claims 1 to 4, wherein the pressing plate is a diaphragm of a photographing lens.

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