JP2007163656A - Photographic lens, and optical apparatus using photographic lens - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To highly precisely and surely carry out the mutual positioning and optical axis alignment of lenses while successively stacking a plastic lens and a glass lens in a lens barrel in fixing the plastic lens and the glass lens having dispersion in outside diameter. <P>SOLUTION: The lower plastic lens 3, an inner light-shielding plate 6, the intermediate plastic lens 4, an inner light-shielding plate 7 and the upper plastic lens 5 are successively inserted into the lens barrel 2 through the opening part of the lens barrel 2. The alignment of the optical axes S of respective plastic lenses 3, 4 and 5 are performed by the tapered surfaces 3d, 4d, 4e and 5b, respectively, and the centering of the optical axes S of respective plastic lenses 3, 4 and 5 related to the lens barrel 2 is pressed into the upper plastic lens 5 as a final insertion lens into the lens barrel 2. Thereafter, the optical axis S of the upper plastic lens 5 is aligned with the optical axis S of the glass lens 8, and a fixing and holding member 9 is loaded to the already centered lens barrel 2 as a whole to press down respective lenses 3, 4 and 5 in the optical axis direction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention is a photographic lens in which a plurality of lenses are stacked in the optical axis direction and accommodated in a lens barrel and an optical device using the photographic lens, particularly when a plurality of lenses are stacked and accommodated in a lens barrel. The present invention relates to a photographing lens that can align the optical axes by aligning the stacked lenses and align the optical axes, and an optical device such as a camera, a digital camera, and a mobile communication device using the photographing lens.

  2. Description of the Related Art Conventionally, photographing lenses in which a plurality of lenses including a plastic lens and a glass lens are fixed in a lens barrel are known. Such a photographic lens that combines multiple lenses must be assembled so that the optical axes of each lens coincide with each other and the optical axes are at the center of the lens barrel. To do. For this reason, for example, the photographic lens disclosed in Patent Document 1 discloses a photographic lens in which a plurality of lenses having different outer diameters are fixed in a lens barrel. In this photographic lens, two steps are formed on the inner surface of the lens barrel, a first lens in which the object side is fixed by a press ring is incorporated in the large-diameter step portion, and the object side is the first in the small-diameter step portion. A second lens that is in contact with one lens, a spacing ring that is interposed between the second and third lenses and serves as a diaphragm that defines the spacing between the second and third lenses, and the object side abuts the spacing ring. A third lens that is brought into contact with and in contact with the inner flange of the lens barrel is fitted.

Japanese Patent Laid-Open No. 7-5354

  However, in such a photographing lens, although lenses corresponding to the step portions having different diameters formed on the inner surface of the lens barrel are press-fitted to position each lens with respect to the lens barrel, the lenses are adjusted to each other. Instead of centering and positioning, it is difficult to align the optical axes between the lenses with high accuracy. For this reason, for example, as a photographing lens for a camera incorporated in a mobile communication device such as a mobile phone, a photographing lens that is aligned with each other so that the optical axes of the lenses are aligned and incorporated in a lens barrel has been developed. As shown in FIG. 3, three plastic lenses 51, 52, 53 and one glass lens 54 are incorporated in a lens barrel 50, and the uppermost plastic lens 51 on the uppermost part on which the glass lens 54 is placed is arranged in two stages. An outwardly tapered surface 55 and an inwardly tapered surface 56 for positioning the optical axes of the lenses 51 and 52 are respectively formed on the overlapping surface of the intermediate plastic lens 52 of the eye. Further, the upper plastic lens 51 and the lower plastic lens 53 are press-fitted with the outer periphery of each lens 51, 53 into the inner peripheral surface of the lens barrel 50 in order to make the center of the lens barrel 50 coincide with the optical axis of each lens 51, 53. ing. In order to align the optical axes of the upper plastic lens 51 and the glass lens 54, an annular protrusion 54a is formed at the center of the upper surface of the upper plastic lens 51, and the glass lens 54 is disposed on the inner side.

  By the way, the plastic lenses 51, 52, and 53 can be integrally molded using a mold. Therefore, the molding process is easy and the dimensional accuracy can be high, but the glass lens 54 is molded by grinding one by one. Therefore, although it is possible to manufacture the center of the outer diameter and the center of the optical axis, the outer diameter size is large and has a drawback of variation.

  Therefore, a clearance for absorbing a molding error of the glass lens 54 is formed between the annular protrusion 54 a and the glass lens 54, and the optical axis of the glass lens 54 is aligned with the upper plastic lens 51. Are bonded and fixed together with an adhesive. However, due to the structure of the lens barrel 50, the glass lens 54 cannot align the optical axis with respect to the upper lens 51 in a state of being incorporated in the lens barrel 50. Therefore, when assembling the lenses 51, 52, 53 to the lens barrel 50, first, the upper plastic lens 51 and the second intermediate plastic lens 52 are brought into surface contact by the respective tapered surfaces 55, 56, and the position of the optical axis is determined. Can be combined. Next, the optical axes of the upper plastic lens 51 and the glass lens 54 are aligned. When aligning the upper plastic lens 51 and the glass lens 54, an alignment jig in which a lower plastic lens is assembled to a dummy barrel is prepared, and the upper and intermediate plastic lenses are integrated with the alignment jig. 51 and 52 are assembled. At this time, the dummy barrel of the alignment jig used has an open upper surface, and the alignment operation of the uppermost glass lens 54 can be performed with respect to the upper plastic lens 51 assembled to the alignment jig. It is like that. The upper and intermediate plastic lenses 51 and 52 pre-aligned in this way are assembled to the alignment jig, and then the glass lens 54 is attached to the annular protrusion 54a of the upper plastic lens 51, whereby the alignment treatment is performed. The optical axis of the glass lens 54 is aligned with the upper and intermediate plastic lenses 51 and 52 and the dummy lower lens assembled to the fixture, and after alignment, the upper plastic lens 51 and the glass lens 54 are integrated with an adhesive. By fixing them, the optical axes of the upper and intermediate plastic lenses 51 and 52 and the glass lens 54 are aligned and aligned, and this is mounted on the lens barrel 50 as the final product. Then, the lower plastic lens 53 is press-fitted into the lens barrel 50 to align the center of the lens barrel 50 with the optical axis of the lower plastic lens 53.

  Therefore, in the photographic lens shown in FIG. 3, the upper plastic lens 51 and the intermediate plastic lens 52 can be easily aligned with each other by abutting the respective tapered surfaces 55 and 56, but are assembled to the upper plastic lens 51. If the glass lens 54 is not assembled to the alignment jig, the optical axis cannot be aligned. Moreover, since the upper and intermediate lenses 51 and 52 and the glass lens 54 are aligned using the alignment jig, the alignment of the lenses 51 and 52 and the glass lens 54 with respect to the lens barrel 50 to be finally assembled is Since this is not performed, the alignment accuracy of the lenses 51 and 52 and the glass lens 54 with respect to the lens barrel 50 may be distorted due to a molding error of the lens barrel 50 that is finally incorporated. Furthermore, since the alignment work is performed many times, the work process is complicated, and there is a risk of dust and dirt adhering to the lens during the lens alignment work process. It is disadvantageous.

  The present invention has been made in view of the circumstances as described above, and in a photographing lens in which a plurality of lenses are positioned and fixed in a lens barrel, when the plurality of lenses are fixed in the lens barrel, the lenses are sequentially attached to the lens barrel. An object of the present invention is to provide a photographing lens capable of surely aligning the optical axes of a plurality of lenses and a lens barrel with high accuracy, and an optical apparatus using the same.

  The photographic lens according to claim 1 is a photographic lens in which a plurality of lenses are stacked in the optical axis direction and accommodated in a lens barrel, and the lens barrel has a mounting flange portion on an inner peripheral bottom portion and has an upper surface. And a tapered surface for aligning the optical axis of each lens is formed on the overlapping surface of each lens, and each lens has an upper surface opening of the lens barrel. When the lenses are assembled in the lens barrel, the taper surface of the upper lens is brought into surface contact with the taper surface of the lower lens when the lenses are assembled into the lens barrel. After aligning the optical axis of each lens, a fixing holding member is attached to the upper surface opening of the lens barrel, and each lens is clamped between the fixing holding member and the mounting flange portion described above. It is characterized by being pressed in the direction of the optical axis. .

  The photographic lens according to claim 2 is the photographic lens according to claim 1, wherein an outer peripheral surface of one of the lenses is press-fitted into an inner peripheral surface of the lens barrel, and the optical axis of the lens and the lens barrel are Alignment with the center is performed, and the other lenses are characterized in that a clearance is formed between them and the lens barrel.

  The photographic lens according to claim 3 is the photographic lens according to claim 1 or 2, wherein each of the lenses is composed of a glass lens arranged at the uppermost stage and a plurality of plastic lenses superimposed on the lower part thereof. An annular protrusion is formed at the center of the upper surface, and the glass lens is superimposed on the upper plastic lens with a clearance inside the annular protrusion, and the glass lens is aligned with the optical axis of the upper plastic lens. After aligning the optical axis, the upper plastic lens and the glass lens are integrated.

  According to a fourth aspect of the present invention, in the photographing lens according to any one of the first to third aspects, an intersection of virtual extension lines of the tapered surface is on the same axis as the lens barrel.

  An optical device according to a fifth aspect is characterized in that the photographing lens according to any one of the first to fourth aspects is used.

  According to another aspect of the present invention, there is provided a photographic lens in which a plurality of lenses are stacked in the optical axis direction and accommodated in a lens barrel, and the lens barrel has a mounting flange portion at an inner peripheral bottom portion. The upper surface of each lens is formed into a cylindrical shape, and a tapered surface for aligning the optical axis of each lens is formed on the overlapping surface of each lens. Stacked sequentially from the opening on the top surface to the mounting flange and housed in the lens barrel. When each lens is assembled into the lens barrel, the taper surface of the upper lens is in surface contact with the taper surface of the lower lens. Then, after aligning the optical axis of each lens, a fixed holding member is attached to the upper surface opening of the lens barrel, and each lens is sandwiched between the fixed holding member and the mounting flange portion, thereby The lens is pressed in the direction of the optical axis. From the upper surface opening of the lens barrel, the lenses are inserted sequentially, and the optical axis of each lens is aligned on the mounting flange portion of the lens barrel by the tapered surface formed on the overlapping surface of each lens. They can be stacked and assembled into the lens barrel. For this reason, since alignment can be performed easily without using a dedicated alignment jig, the alignment operation process is reduced, and fine dust, dust, or dirt adheres to the lens during alignment operations. It can be suppressed as much as possible, and the working process can be greatly shortened.

  According to a second aspect of the present invention, in the photographing lens according to the first aspect, the outer peripheral surface of one of the lenses is press-fitted into the inner peripheral surface of the lens barrel, and the optical axis of the lens and the mirror The lens is aligned with the center of the tube, and the other lenses have a clearance between them and the lens barrel. By press-fitting into the lens barrel, it is possible to align the lens with respect to the center of the lens barrel, and the optical axis is aligned by the tapered surface formed on the respective overlapping surfaces of the lens and other lenses. Therefore, alignment of the optical axes of all the lenses with respect to the lens barrel can be performed by press-fitting one lens into the lens barrel.

  According to a third aspect of the present invention, in the photographing lens according to the first or second aspect, each lens is composed of a glass lens arranged at the uppermost stage and a plurality of plastic lenses superimposed on the lower part, and an upper plastic. An annular protrusion is formed at the center of the upper surface of the lens, and the glass lens is superimposed on the upper plastic lens with a clearance inside the annular protrusion, and the glass is aligned with the optical axis of the upper plastic lens. After aligning the optical axis of the lens, the upper plastic lens and the glass lens are integrated, so after the alignment of the optical axis of all the plastic lenses with respect to the lens barrel is completed, the upper stage located at the top All lenses are aligned by aligning the optical axes of all plastic lenses, including plastic lenses, and glass lenses. It can perform alignment operation in a state incorporated in lens barrel.

  According to the photographic lens of claim 4, in the photographic lens according to any one of claims 1 to 3, the intersection of the virtual extension lines of the tapered surface is on the same axis as the lens barrel. By fitting the tapered surfaces formed on the overlapping surfaces to each other, it is possible to align the optical axis of each lens with the central axis of the lens barrel.

  According to the optical device of the fifth aspect, since the photographing lens according to any one of the first to fourth aspects is used, the alignment operation of the photographing lens in the optical device can be simplified.

  Hereinafter, an embodiment as the best mode for carrying out the present invention will be described with reference to FIGS. Of course, it goes without saying that the present invention can be easily applied to other than those described in the embodiments without departing from the spirit of the invention.

  1 is a cross-sectional view of a photographic lens according to an embodiment of the present invention, FIG. 2 is a cross-sectional view showing an exploded state of the photographic lens shown in FIG. 1, and the photographic lens 1 of the present embodiment includes a lens barrel 2, Plastic lenses 3, 4, and 5 made of plastic material, inner light shielding plates 6 and 7 interposed between the plastic lenses 3, 4, and 5, and a glass lens 8 disposed on the upper plastic lens 5 are fixed. It is comprised from the holding member 9 grade | etc.,.

  The lens barrel 2 is formed in a cylindrical shape that is open at the top and bottom as a whole, and is integrally formed with a mounting flange portion 10 closer to the inner periphery toward the center. In addition, a male screw portion 9a formed on the outer peripheral surface of the fixed holding member 9 and a female screw portion 2a to be screwed are formed on the upper inner peripheral surface of the opening, and the lower plastic lens 3, After the inner light shielding plate 6, the intermediate plastic lens 4, the inner light shielding plate 7, the upper plastic lens 5, and the glass lens 8 are sequentially stacked and accommodated in the lens barrel 2, the fixed holding member 9 is attached to the female screw portion 2 a of the lens barrel 2. By screwing the male screw portion 9a, the lower plastic lens 3, the inner light shielding plate 6, the intermediate plastic lens 4, the inner light shielding plate 7, and the upper plastic lens 5 accommodated in the lens barrel 2 are pressed in the optical axis direction. In addition, an opening window 12 corresponding to the glass lens 8 is formed at the center of the fixed holding member 9, and a protective glass 14 a is fitted into a recess 13 provided on the front surface of the fixing window 9. A filter 14b for cutting infrared rays is fitted.

  The upper plastic lens 5 is a convex lens made of a plastic material having an annular protrusion 15 for positioning the glass lens 8 at the center of the object side (upper surface side) and having a concave lens surface on the image surface side. The first flat portion 5a, the outward conical tapered surface 5b, and the second flat portion 5c are formed concentrically in order from the first.

  The intermediate plastic lens 4 is a convex lens that is interposed between the upper plastic lens 5 and the lower plastic lens 3 and has a concave lens surface on the object side and a convex lens surface on the image surface side. Further, the intermediate plastic lens 4 has a concave lens surface, a flat plate portion 4c having first and second flat surfaces 4a and 4b on the front and back surfaces located on the outer peripheral portion of the convex lens surface, and conical shapes on the inner surface and outer surface, respectively. An inclined wall 4f having tapered surfaces 4d and 4e and a flange 4h having a third flat surface 4g on the lower surface are formed concentrically.

  The lower plastic lens 3 is a convex lens having a concave lens surface on the object side and a convex lens surface on the image surface side, and flat portions 3a on the front and back for mounting on the mounting flange portion 10 on the outer periphery of the concave lens surface and the convex lens surface. , 3b are formed concentrically, and a protrusion 3e having an inwardly tapered surface 3d is provided on the upper surface side of the flange 3c so as to position the intermediate plastic lens 4 in a protruding manner. ing. In this way, the respective plastic lenses 3, 4, 5 are formed with tapered surfaces 3d, 4d, 4e, 5b on the respective overlapping surfaces, and these tapered surfaces 3d, 4d, 4e, 5b are brought into surface contact with each other. By fitting, the optical axes S of the plastic lenses 3, 4, and 5 are aligned. That is, the intersections of the virtual extension lines of the tapered surfaces 3d, 4d, 4e, and 5b coincide with the optical axis S. The upper plastic lens 5 is press-fitted into the inner peripheral surface of the lens barrel 2 so that the center of the lens barrel 2 is aligned with the optical axis S of the upper plastic lens 5. The other plastic lenses 3 and 4 are mirrors. A clearance is set between the inner peripheral surface of the tube 2 and a slight gap is formed between the outer periphery of the middle and lower plastic lenses 3 and 4 excluding the upper plastic lens 5 and the inner peripheral surface of the lens barrel 2. It is formed.

  The inner light shielding plates 6 and 7 are in the form of a sheet made of a synthetic resin material or the like, and the inner diameter portions function as throttle holes 6a and 7a. Each of the inner light shielding plates 6 and 7 is interposed between flat surfaces 3a, 4a, 4b, and 5a located on the overlapping surface of the plastic lenses 3, 4, and 5.

  The glass lens 8 is a convex lens having convex lens surfaces on the object side and the image plane side, and is disposed inside the annular protrusion 15 formed on the upper plastic lens 5 and is bonded and fixed to the glass lens 8. A clearance for absorbing a molding error of the glass lens 8 is formed between the annular protrusion 15 and the glass lens 8, and the optical axis S of the glass lens 8 is aligned with the upper plastic lens 5 before bonding. It is bonded and fixed integrally with the material.

  Next, the procedure for assembling the photographic lens 1 will be described. When the photographing lens 1 is assembled, as shown in FIG. 2, the upper surface opening of the lens barrel 2 is opened. First, from the upper surface opening, the lower plastic lens 3, the inner light shielding plate 6, the intermediate plastic lens 4, and the inner light shielding plate. 7. The upper plastic lens 5 is sequentially inserted and placed on the placement flange 10. At this time, when the intermediate plastic lens 4 is superimposed on the lower plastic lens 3 with the inner light shielding plate 6 interposed, the inwardly tapered surface 3d formed on the protruding portion 3e of the lower plastic lens 3 and the intermediate plastic lens 4 are formed. An outwardly tapered surface 4e is fitted to the inclined wall 4f so that the optical axes S of the lower plastic lens 3 and the intermediate plastic lens 4 are aligned. Further, when the upper plastic lens 5 is superimposed on the intermediate plastic lens 4 with the inner light shielding plate 7 interposed, the inwardly tapered surface 4d formed on the inclined wall 4f of the intermediate plastic lens 4 and the upper plastic lens 5 facing outward. And the optical axis S of the upper plastic lens 5 and the intermediate plastic lens 4 are aligned, thereby aligning the optical axes S of the plastic lenses 3, 4 and 5, respectively. The Further, the upper plastic lens 5 located at the uppermost portion is press-fitted with the outer peripheral edge to the inner peripheral surface of the lens barrel 2 so that the central axis of the lens barrel 2 and the optical axis S of the upper plastic lens 5 are aligned. As a result, the plastic lenses 3, 4, 5 are stacked while the optical axes S of the plastic lenses 3, 4, 5 inserted in the lens barrel 2 are aligned, and the upper plastic lens 5 to be inserted last is attached to the lens barrel 2. The plastic lens 3, 4, 5 is aligned with the lens barrel 2 by press-fitting into the lens barrel 2, and finally, the plastic lens 3, 4 is pressed into the lens barrel 2 by press-fitting the upper plastic lens 5. , 5 are integrated. Thereafter, the glass lens 8 is disposed in the annular protrusion 15 of the aligned upper plastic lens 5 and the optical axis of the glass lens 8 is adjusted, and then the upper plastic lens 5 and the glass lens 8 are integrated with an adhesive. Turn into. As a result, the optical axes S of the lenses 3, 4, 5, and 8 are aligned, and the optical axes of all the lenses 3, 4, 5, and 8 with respect to the central axis of the barrel 2 with the upper plastic lens 5 as a reference. Alignment with S is completed. Thereafter, by screwing the male screw portion 9a of the fixing holding member 9 to the female screw portion 2a of the lens barrel 2, the lower plastic lens 3, the inner light shielding plate 6, the intermediate plastic lens 4, and the inner plastic lens 3 housed in the lens barrel 2 are secured. The light shielding plate 7 and the upper plastic lens 5 are pressed in the optical axis direction.

  As described above, in this embodiment, the upper surface of the lens barrel 2 is opened, and the lower plastic lens 3, the inner light shielding plate 6, the intermediate plastic lens 4, the inner light shielding plate 7, and the upper plastic lens 5 are sequentially formed from the opening. Are sequentially inserted, and the optical axes S of the plastic lenses 3, 4, 5 are sequentially aligned by the tapered surfaces 3d, 4d, 4e, 5b formed on the overlapping surfaces of the plastic lenses 3, 4, 5 respectively. The upper plastic lens 5 that is stacked on the mounting flange portion 10 of the lens barrel 2 and finally inserted is press-fitted into the lens barrel 2, so that the optical axis S of each plastic lens 3, 4, 5 with respect to the lens barrel 2 can be reduced. Alignment can be performed, and the optical axis S of the glass lens 8 with respect to the upper plastic lens 5 in a state where the alignment operation of the plastic lenses 3, 4, 5 is completed with respect to the lens barrel 2 in this way Position It is possible to go to alignment. For this reason, as in the prior art, the plastic lens is aligned before the lens barrel 2 is set, and then the glass lens is aligned with respect to the plastic lens that has been aligned using the alignment jig. The lens can be aligned very easily without the need for an alignment process. Moreover, since the lower plastic lens 3, the inner light shielding plate 6, the intermediate plastic lens 4, the inner light shielding plate 7, and the upper plastic lens 5 are sequentially inserted into the lens barrel 2 as the final product, the assembled photographing can be performed. The accuracy of the lens 1 can also be kept high. In addition, since there are few work processes associated with alignment, it is possible to prevent fine dust, dust, dirt, and the like from adhering to the lens during these work operations, and it is possible to greatly shorten the work process.

  As mentioned above, although the Example of this invention was explained in full detail, this invention is not limited to the said Example, A various deformation | transformation implementation is possible within the range of the summary of this invention. For example, in order to match the shape of each lens and the optical axis of each lens, basic structures such as a fitting structure, the number of lenses, and a lens pressing structure may be appropriately selected.

It is sectional drawing of the imaging lens which shows one Example of this invention. FIG. 3 is a cross-sectional view in which a part of the exploded state of the photographing lens is omitted. It is sectional drawing of the imaging lens which shows a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Shooting lens 2 Lens tube 3, 4, 5 Plastic lens 3d, 4d, 4e, 5b Tapered surface 8 Glass lens 9 Fixed holding member 10 Mounting flange part 15 Annular protrusion S Optical axis

Claims (5)

  A photographic lens in which a plurality of lenses are stacked in the optical axis direction and accommodated in a lens barrel, and the lens barrel is formed in a cylindrical shape having a mounting flange portion on an inner peripheral bottom portion and having an upper surface opened. In addition, a taper surface for aligning the optical axes of the lenses is formed on the overlapping surface of the lenses, and the lenses are placed on the mounting flange portion from the upper surface opening of the lens barrel. Stacked one after another and accommodated in the lens barrel, and when assembling each lens in the lens barrel, the tapered surface of the upper lens is in surface contact with the tapered surface of the lower lens to align the optical axis of each lens After that, by attaching a fixed holding member to the upper surface opening of the lens barrel and sandwiching each lens between the fixed holding member and the mounting flange portion, each lens is pressed in the optical axis direction. Characteristic photographic lens.   The outer peripheral surface of one of the lenses is press-fitted into the inner peripheral surface of the lens barrel so as to be aligned with the optical axis of the lens and the center of the lens barrel, and the other lenses are The photographic lens according to claim 1, wherein a clearance is formed between the two.   Each lens is composed of a glass lens arranged at the uppermost stage and a plurality of plastic lenses superimposed on the lower part thereof, and an annular protrusion is formed at the center of the upper surface of the upper plastic lens. The upper plastic lens and the glass lens were integrated after aligning the optical axis of the glass lens with the optical axis of the upper plastic lens with a clearance inside the protrusion and overlaying on the upper plastic lens. The photographic lens according to claim 1 or 2, wherein   The photographing lens according to any one of claims 1 to 3, wherein the intersection of the virtual extension lines of the tapered surface is on the same axis as the lens barrel. An optical apparatus using the photographing lens according to claim 1.

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