JP2007163657A - Photographic lens, and optical apparatus using photographic lens - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the assemblage accuracy of a photographic lens from being affected by dispersion in molding accuracy of an inner light-shielding plate interposed between lenses. <P>SOLUTION: In stacking respective plastic lenses 3, 4 and 5 on top of one another, the apex parts 3f and 4i of projecting step parts 3d and 4d are brought in contact with the receiving surfaces 4g and 5c of recessed step parts 4h and 5e. Consequently, clearances t1, t2 equivalent to the plate thickness of the inner light-shielding plates 6, 7 are formed between placing surfaces 3a, 4a and the holding surfaces 4e, 5a, respectively, and the clearances t1 and t2 are kept constant even when the dispersion of the plate thickness arises due to the molding error of the inner light-shielding plates 6 and 7. Thus, the assembling accuracy of the assembled photographic lenses is highly precisely maintained without causing the dispersion 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 capable of suppressing assembling errors of stacked lenses as much as possible, and an optical apparatus such as a camera, a digital camera, and a mobile communication device using the photographing lens.

  2. Description of the Related Art Conventionally, a photographing lens is known in which a plurality of lenses including a plastic lens and a glass lens are fixed in a lens barrel. For example, the applicant of the present application in Patent Document 1 causes a plurality of lenses to contact each other in the optical axis direction. Have proposed a lens positioning method capable of determining a positional relationship between optically or physically facing lenses, and an optical apparatus to which the method is applied. As shown in FIG. 4, the photographing lens includes a lens barrel 51, a plastic front lens 52, an elastic inner light shielding plate 53, an intermediate lens 54, an elastic lens regulating member 55, a plastic rear lens 57, An inner light shielding plate 56 and a fixed holding member 58 are included.

JP 2002-286987 A

  4, when assembled, the front lens 52, the inner light shielding plate 53, the intermediate lens 54, the lens regulating member 55, the inner light shielding plate 56, the rear lens 57, and the fixed holding member 58 are sequentially arranged with respect to the lens barrel 51. insert. At this time, the optical surfaces S of the lenses 52 and 57 are aligned by bringing the tapered surface 52a of the front lens 52 and the tapered surface 57a of the rear lens 57 into contact with each other. In the overlapping portion, the distal end portion of one tapered surface 52a and the base end edge of the other tapered surface 57a are separated to form a gap t, and the inner light shielding plate 53 interposed between the lenses 52, 54, 57. , 56 are sandwiched between the lenses 52, 54, 57. However, the inner light-shielding plates 53 and 56 are formed of a synthetic resin such as plastic that is easy to mold, are formed of a relatively low-rigidity material, and the thickness tends to be distorted by the pressing force received from the lenses 52, 54, and 57. In addition, the thickness of the inner light shielding plates 53 and 56 is likely to vary due to molding errors and the like. For this reason, as shown in FIG. 4, it is difficult to maintain the assembly accuracy of the assembled photographic lens in a structure in which a gap t is formed between the distal end portion of one tapered surface 52a and the base end edge of the other tapered surface 57a. There is a problem that the optical performance of the photographing lens assembled by such a variation in assembly accuracy is also affected.

  The present invention has been made in view of the above circumstances, and in a photographic lens in which a plurality of lenses are positioned and fixed in a lens barrel, the photographic lens has a variation due to variations in molding accuracy of an inner light shielding plate interposed between the lenses. An object of the present invention is to provide a photographic lens that can be reliably and accurately performed without affecting the assembly 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 and an inner light shielding plate interposed between the lenses are stacked in the optical axis direction and housed in a lens barrel. Stepped convex portions and stepped concave portions each having a tapered surface are formed on the overlapping surface, and when the lenses are stacked and accommodated in the lens barrel, the stepped convex portions and the tapered surfaces of the stepped concave portions are brought into surface contact with each other. The optical axes of the upper and lower lenses are aligned, and a gap is formed between the step protrusion and the step recess to place the inner light shielding plate between the step protrusion and the step recess. Features.

  According to a second aspect of the present invention, there is provided the photographing lens according to the first aspect, wherein a mounting surface on which the inner light-shielding plate is placed on the lower lens and an inner surface that rises in an inclined manner from the outer periphery of the mounting surface. The step convex portion is formed by a direction taper surface and a step convex surface facing outward from the inward taper surface, and the upper lens has a holding surface facing the mounting surface, and an outside of the holding surface. The step concave portion is formed by an outwardly tapered surface that rises in an inclined manner from the periphery and a receiving surface that extends outward from the outwardly tapered surface, and when the lenses are stacked and accommodated in the lens barrel, The optical surfaces of the upper and lower lenses are aligned with each other by bringing the tapered surfaces of the concave portion and the step concave portion into surface contact, and a gap corresponding to the thickness of the inner light shielding plate is formed between the mounting surface and the holding surface. Characterized by

  According to a third aspect of the present invention, in the photographing lens according to the second aspect, the top of the convex surface of the step is abutted against the receiving surface and the thickness of the inner light shielding plate is set between the mounting surface and the holding surface. A corresponding gap is formed.

  The photographic lens according to claim 4 is the photographic lens according to any one of claims 1 to 3, wherein the lens is a lower plastic lens, an intermediate plastic lens, an upper plastic lens, and an upper surface of the upper plastic lens. It is comprised by the glass lens arrange | positioned by this, The said internal light-shielding board is interposed and arrange | positioned between each plastic lens, It is characterized by the above-mentioned.

  According to a fifth aspect of the present invention, in the photographing lens according to any one of the first to fourth aspects, the inner light shielding plate is formed of a synthetic resin.

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

  An optical apparatus according to a seventh aspect is characterized in that the photographing lens according to any one of the first to sixth aspects is used.

  The photographic lens according to claim 1 is a photographic lens in which a plurality of lenses and an inner light shielding plate interposed between the lenses are stacked in the optical axis direction and housed in a lens barrel. Stepped convex portions and stepped concave portions each having a tapered surface are formed on the overlapping surface, and when the lenses are stacked and accommodated in the lens barrel, the stepped convex portions and the tapered surfaces of the stepped concave portions are brought into surface contact with each other. In addition to aligning the optical axes of the upper and lower lenses, a gap is formed between the step protrusion and the step recess to place the inner light shielding plate between the step protrusion and the step recess. Therefore, even if the thickness of the inner shading plate varies due to molding errors, it is possible to reliably secure a gap for placing the inner shading plate between the step protrusion and the step recess, and the assembly accuracy of the assembled photographic lens is increased. High without any variation in the optical axis direction It is possible to keep every time.

  According to a second aspect of the present invention, in the photographing lens according to the first aspect, the mounting surface on which the inner light-shielding plate is mounted on the lower lens and the outer peripheral edge of the mounting surface are inclined. The stepped convex portion is formed by a rising inwardly tapered surface and a stepped convex surface facing outward from the inwardly tapered surface, and the upper lens has a holding surface facing the mounting surface, and the holding surface The stepped recess is formed by an outwardly tapered surface rising in an inclined manner from the outer peripheral edge of the lens and a receiving surface facing outward from the outwardly tapered surface, and when the lenses are stacked and accommodated in the lens barrel, The stepped convex portion and the tapered surface of the stepped concave portion are brought into surface contact with each other to align the optical axes of the upper and lower lenses, and a gap corresponding to the thickness of the inner light shielding plate between the mounting surface and the holding surface. Each lens is stacked to create a mirror. When accommodating within, it is possible to reliably ensure the gap to place the inner shielding plate between the retaining surface on the mounting surface and the upper lens side of the lower lens side for placing the inner shielding plate.

  According to a third aspect of the present invention, there is provided the photographing lens according to the second aspect, wherein the top of the convex surface of the step is abutted against the receiving surface and the plate of the inner light shielding plate is placed between the mounting surface and the holding surface. Since a gap corresponding to the thickness is formed, the top surface of the convex surface of the step is abutted against the receiving surface, thereby placing the light shielding plate between the mounting surface on the lower lens side and the holding surface on the upper lens side. A gap in which the inner light shielding plate is disposed can be ensured.

  According to a photographic lens according to claim 4, in the photographic lens according to any one of claims 1 to 3, the lens is a lower plastic lens, an intermediate plastic lens, an upper plastic lens, and the upper plastic lens. It is constituted by a glass lens arranged on the upper surface of the lens, and the inner light-shielding plate is interposed between the plastic lenses.When the lenses are stacked and accommodated in the lens barrel, The tapered surfaces can be brought into surface contact with each other to ensure alignment of the optical axes of the upper and lower lenses, and the assembling accuracy of the photographic lens can be improved in the optical axis direction due to variations in the thickness of the inner light shielding plate disposed between the upper and lower lenses. High accuracy can be maintained without variation.

  According to the photographing lens according to claim 5, in the photographing lens according to any one of claims 1 to 4, since the inner light shielding plate is formed of a synthetic resin, a material having low rigidity as the inner light shielding plate. Even if it is formed, the pressing force received from the upper and lower lenses does not act on the inner light shielding plate, so that the assembling accuracy of the photographing lens does not vary in the optical axis direction due to the variation in the thickness of the inner light shielding plate, and can be maintained with high accuracy it can.

  According to the photographing lens according to claim 6, in the photographing lens according to any one of claims 1 to 5, each intersection point of the virtual extension lines of the tapered surface is on the same axis as the lens barrel. By aligning the tapered surfaces formed on the overlapping surfaces of the lenses, the optical axis of each lens and the center axis of the lens barrel can be aligned.

  According to the optical device of the seventh aspect, since the photographing lens according to any one of the first to sixth 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 an exploded view of the photographic lens shown in FIG. 1, and FIG. 3 is an enlarged cross-sectional view of an overlapping portion of the lenses. The photographic lens 1 includes a lens barrel 2, plastic lenses 3, 4, 5 made of plastic material, inner light shielding plates 6, 7 interposed between the plastic lenses 3, 4, 5, and the upper plastic lens 5. It is comprised from the glass lens 8 arrange | positioned by this, and the fixed 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. Further, a female screw portion 2a for screwing a male screw portion 9a formed on the outer peripheral surface of the fixed holding member 9 is formed on the opened upper inner peripheral surface, 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 holding surface 5a, the conical outward tapered surface 5b, and the first receiving surface 5c are formed concentrically in order from the first holding surface 5a, the outward tapered surface 5b, and the first receiving surface. A first step recess 5e is formed by the surface 5c.

  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 surface side of the intermediate plastic lens 4 is located on the outer peripheral portion of the concave lens surface, the first placement surface 4a supporting the inner light shielding plate 7, the conical inwardly tapered surface 4b, the first step. The convex surface 4c is formed concentrically, and the first step convex portion 4d is formed by the first placement surface 4a, the inwardly tapered surface 4b, and the first step convex surface 4c. Further, on the back surface side of the intermediate plastic lens 4, a second holding surface 4e, a conical outward taper surface 4f, and a second receiving surface 4g are formed concentrically on the outer periphery of the convex lens surface. The second holding surface 4e, the outward taper 4f, and the second receiving surface 4g form a second step recess 4h.

  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 a second mounting surface 3a for supporting the inner light shielding plate 6 on the outer periphery of the concave lens surface, and a conical inward direction. A tapered surface 3b and a second stepped convex surface 3c are formed concentrically, and a stepped convex portion 3d is formed by the second mounting surface 3a, the inwardly tapered surface 3b, and the second stepped convex surface 3c. . Further, the back surface side of the lower plastic lens 3 is formed with a flat surface 3e which is located on the outer peripheral portion of the convex lens surface and is placed on the mounting flange portion 10 described above. In this way, each plastic lens 3, 4, 5 is formed with stepped convex portions 3d, 4d and stepped concave portions 4h, 5e having tapered surfaces 3b, 4b, 4f, 5b on the respective overlapping surfaces. By aligning the stepped convex portions 3d, 4d and the stepped concave portions 4h, 5e and bringing the respective tapered surfaces 3b, 4b, 4f, 5b into surface contact, the optical axes S of the plastic lenses 3, 4, 5 are aligned. Is done. That is, the intersection of the virtual extension lines of the tapered surfaces 3d, 4b, 4e, and 5b coincides 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 and the optical axis S of the upper plastic lens 5 are aligned, but 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 such as plastic, and the inner diameter portions function as throttle holes 6a and 7a. Each of the inner light shielding plates 6, 7 has a second placement surface 3 a, a second holding surface 4 e, a first placement surface 4 a, and a first placement position that are positioned on the overlapping surface of the plastic lenses 3, 4, 5. Between the holding surfaces 5a.

  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 inner light shielding plate 6 is placed on the second placement surface 3a of the lower plastic lens 3 and the intermediate plastic lens 4 is overlaid, the second step convex portion 3d of the lower plastic lens 3 is formed. The inwardly tapered surface 3b and the outwardly tapered surface 4f formed in the second step recess 4h of the intermediate plastic lens 4 are fitted, and the optical axis S between the lower plastic lens 3 and the intermediate plastic lens 4 is positioned. To be combined. Further, when the inner light shielding plate 7 is placed on the first placement surface 4 a of the intermediate plastic lens 4 and the upper plastic lens 5 is overlapped, the inner step formed on the first step convex portion 4 d of the intermediate plastic lens 4 is formed. The taper surface 4b facing and the outward taper surface 5b formed in the first step recess 5e of the upper plastic lens 5 are fitted, and the optical axis S between the upper plastic lens 5 and the intermediate plastic lens 4 is aligned. Thus, the optical axes S of the respective plastic lenses 3, 4, 5 are aligned. 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 aligning the optical axes S of the plastic lenses 3, 4, 5 inserted into the lens barrel 2, and the upper plastic lens 5 to be inserted last is attached to the lens barrel 2. The plastic lenses 3, 4, 5 are aligned with each other by aligning the optical axes S of the plastic lenses 3, 4, 5 with respect to the lens barrel 2, and finally the upper plastic lens 5 is press-fitted into the lens barrel 2. Is integrated. Further, when the first and second stepped protrusions 4d and 3d are fitted to the first and second stepped protrusions 5e and 4h, the tops 3f of the first and second stepped protrusions 4d and 3d, 4i hits the first and second receiving surfaces 5c and 4g of the first and second stepped recesses 5e and 4h, and the first and second placement surfaces 4a and 3a and the first and second holding surfaces 5a. , 4e, gaps t1, t2 corresponding to the thickness of the inner light shielding plates 6, 7 are formed. 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 3b, 4b, 4f, 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.

  Further, when the plastic lenses 3, 4, 5 are stacked, the first and second step protrusions 4d, 3d and the first and second step recesses 5e, 4h are fitted together. The top portions 3f, 4i of the step protrusions 4d, 3d abut against the first and second receiving surfaces 5c, 4g of the first and second step recesses 5e, 4h, and the first and second placement surfaces 4a, 3a. And gaps t1 and t2 corresponding to the thickness of the inner light shielding plates 6 and 7 are formed between the first and second holding surfaces 5a and 4e. Since the gaps t1 and t2 do not change due to the variation in thickness or the bending of the inner light shielding plates 6 and 7 due to the pressing force received from the lenses 3, 4, and 5, the assembly accuracy of the assembled photographic lens varies in the optical axis direction. And high accuracy can be maintained.

  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. Further, the shape of the step concave portion and the step convex portion for positioning each plastic lens may be appropriately selected.

It is sectional drawing of the imaging lens which shows one Example of this invention. It is sectional drawing which abbreviate | omitted one part which shows the decomposition | disassembly state of a component same as the above. It is an enlarged sectional view of the overlapping part of a lens same as the above. 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 3a 2nd mounting surface 3b Inward taper surface 3c 2nd level | step convex surface 3d 2nd level | step convex 3f, 4i Top 4a 1st mounting surface 4b Inwardly tapered surface 4c First step convex surface 4d First step convex portion 4e Second holding surface 4f Outward tapered surface 4g Second receiving surface 4h Second step concave portion 5a First holding surface 5b Outward taper Surface 5c 1st receiving surface 5e 1st level | step difference recessed part 6, 7 Inner light shielding plate 8 Glass lens S Optical axis t1, t2 Gap

Claims (7)

  A photographic lens in which a plurality of lenses and an inner light-shielding plate interposed between these lenses are stacked in the optical axis direction and accommodated in a lens barrel, each of the overlapping surfaces of the lenses having a tapered surface When forming the step protrusion and step recess and stacking the lenses in the lens barrel, the taper surfaces of the step protrusion and step recess are brought into surface contact with each other to align the optical axes of the upper and lower lenses. And a gap in which the inner light-shielding plate is disposed between the step protrusion and the step recess by abutting a part of the step protrusion and step recess facing each other.   A mounting surface on which the inner light shielding plate is mounted on the lower lens; an inwardly tapered surface that rises in an inclined manner from the outer peripheral edge of the mounting surface; and a stepped convex surface that faces outward from the inwardly tapered surface The upper surface side lens is formed with a holding surface facing the mounting surface, an outwardly tapered surface rising from an outer peripheral edge of the holding surface, and an outwardly tapered surface. When forming the step concave portion with the receiving surface facing outward and stacking the lenses in the lens barrel, the step convex portion and the tapered surface of the step concave portion are brought into surface contact with each other so that the upper and lower lenses are in contact with each other. 2. The photographic lens according to claim 1, wherein the optical axis is aligned, and a gap corresponding to the thickness of the inner light shielding plate is formed between the mounting surface and the holding surface.   The photographing lens according to claim 2, wherein a gap corresponding to the thickness of the inner light shielding plate is formed between the placement surface and the holding surface by abutting the top of the step convex surface with the receiving surface. .   The lens is composed of a lower plastic lens, an intermediate plastic lens, an upper plastic lens, and a glass lens disposed on the upper surface of the upper plastic lens, and the inner light shielding plate is interposed between the plastic lenses. The photographing lens according to any one of claims 1 to 3, wherein the photographing lens is provided.   The photographic lens according to claim 1, wherein the inner light shielding plate is formed of a synthetic resin.   The photographing lens according to any one of claims 1 to 5, wherein an intersection of 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 any one of claims 1 to 6.

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