JP2011075682A - Optical lens - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate a lens retainer and reduce the size of the diameter of a lens barrel that holds a plastic lens and reduce the size of an optical system lens as a whole. <P>SOLUTION: When first to fourth plastic lenses 4 to 7 are assembled on the lens barrel 2 and an arm portion 35 formed on the lens 7, at a last stage is squeezed with a tool; optical axes S of the lenses 4 to 7 are made to coincide by conical inclined faces 21 and 22 of the respective lenses 4 to 7 and conical contact faces 23 to 26; and a periphery of the lens 7 at the last stage is fixed to an inner peripheral face of the lens barrel 2 with an adhesive agent 40. Here, the arm portion 35 which becomes a pressing force base by the tool for the lens 7 at the last stage is arranged inside a notch portion 36, thereby enabling elimination of dead space by the pressing-force base. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an optical system lens used in a small imaging device used in a small and thin electronic device such as a mobile phone or PDA (Personal Digital Assistance), and in particular, a plurality of lenses are brought into contact with each other in the optical axis direction and stacked. The present invention relates to an optical system lens that determines a positional relationship between optically or physically facing lenses by matching.

  In recent years, with the expansion of the market for portable terminals equipped with an imaging device, a small solid-state imaging device having a high pixel count has been mounted on the imaging device. In response to such downsizing and increase in the number of pixels of an image pickup device, for example, as shown in Patent Documents 1 and 2, an image pickup lens constituted by a plurality of lenses is generalized.

  The imaging lens disclosed in Patent Document 1 includes two plastic lenses, one glass lens, and a lens frame in which these lenses are incorporated, a contact surface between the lens frame and the preceding plastic lens, and two plastics. A conical pressing surface is formed around the optical axis on the contact surface of the lens, and when each lens is incorporated into the lens frame, the plastic lens of the previous stage and the pressing surface formed on the front surface of the lens frame are fitted to each other. Position the frame and the front plastic lens, and in this state, insert the rear plastic lens into the lens frame to engage the contact surfaces of the two plastic lenses, and position them in the optical axis direction of the two plastic lenses. Finally, press fit the glass lens into the lens frame and press the lens presser against the glass lens. The by clamped and to match the optical axis of each plastic lens. In addition, the imaging lens disclosed in Patent Document 2 includes one plastic lens, one glass lens, and a lens barrel in which these lenses are incorporated, and the peripheral area of the lens in contact with the plastic lens and the glass lens is the same. When mounting each lens in a lens frame with a curvature or the same taper surface, contact the first plastic lens contact portion with the receiving surface of the lens barrel, and position the lens barrel and the previous plastic lens in the glass. By pressing the glass lens against the plastic lens and applying pressure in the optical axis direction while fitting the lens to the inner peripheral surface of the lens barrel, the plastic lens is sandwiched between the receiving surface of the lens barrel and the glass lens. The optical axes of the respective lenses are made to coincide with each other by engagement of taper surfaces having the same curvature or the same inclination formed in the peripheral region.

  The imaging lens disclosed in Patent Documents 1 and 2 is a combination of a glass lens and a plastic lens made of different materials, and each lens has a different linear expansion coefficient. May cause damage or cracking. For this reason, in recent years, for example, as shown in FIG. 7, an imaging lens used for a mobile phone or the like is generally formed by plastic lenses F1 to F4, for example, all four lenses incorporated in a lens barrel K. is there. Since such plastic lenses F1 to F4 have lower rigidity than glass lenses, as in Patent Documents 1 and 2, the last glass lens is press-fitted into the lens barrel, and the glass lens and the receiving surface of the lens barrel are plastic. In the method of sandwiching and fixing the lens, there is a problem that the lens surface of the last-stage plastic lens F4 is distorted and the optical performance is deteriorated.

  For this reason, when all the four lenses incorporated in the lens barrel K are constituted by the plastic lenses F1 to F4, the outer diameter of at least the last-stage plastic lens F4 is formed slightly smaller than the inner diameter of the lens barrel K, and the plastic lens The lens F4 is inserted into the lens barrel K while maintaining a radial clearance a between the lens F4 and the lens barrel K. That is, the last plastic lens F4 has a play corresponding to the radial clearance a with respect to the lens barrel K, while the plastic lenses F1 to F4 coincide with the optical axes S of the plastic lenses F1 to F4. In order to achieve this, the first to third plastic lenses F1 to F3 are pressed from behind (the lower side in the figure) with the fourth plastic lens F4 at the last stage, so that they are formed on the overlapping surface of the lenses F1 to F4. The conical abutment surface N aligns the optical axes S of the lenses F1 to F4 with each other.

  As described above, when the last stage plastic lens F4 is inserted into the lens barrel K while being pushed in the optical axis direction with radial play with the lens barrel K, the lens presser H from the rear side of the last stage plastic lens F4. And press the third plastic lens F3, the second plastic lens F2, and the first plastic lens F1 in order from the fourth plastic lens F4, and finally the lens presser H is attached to the lens barrel. The inner peripheral surface of K is bonded and fixed with an adhesive B.

JP-A-56-149010 Japanese Patent Laid-Open No. 9-113783

  In this way, in the structure in which the last stage plastic lens F4 is pressed with the lens holder H, and the lens barrel K is pressed and held with the lens holder H, the lens is attached to the periphery of the lens portion of the last stage plastic lens F4. A region that contacts the presser H is required. In this case, the lens retainer H must also have a predetermined strength, and the lens retainer H must be formed with a relatively large cross-sectional shape. For this reason, the last stage plastic lens F4 that comes into contact with the lens retainer H needs to secure a wide area for abutting the lens retainer H on the periphery of the lens portion A. Therefore, the lens barrel K that houses the plastic lens F4 is used. This is a factor that hinders downsizing of the lens module and, in turn, downsizing of the lens module.

  The present invention has been made in view of the above-described problems, and provides an optical system lens that can reduce the size of the entire optical system lens by reducing the diameter of a lens barrel that includes a plastic lens without using a lens presser. For the purpose.

  An optical system lens according to claim 1 is a plurality of lenses composed of a lens portion and a flange portion, a tapered conical surface centered on the optical axis formed on the overlapping surface of each lens, A lens barrel that stores and holds the lenses in a stacked state, inserts the lenses from the opening of the lens barrel, and sets the outer diameter of the last lens to be smaller than the inner diameter of the lens barrel. In the optical system lens that presses the last stage lens in the optical axis direction and aligns the optical axes of the lenses with each other by the conical surface of each lens, from the periphery of the lens portion of the last face of the last stage lens A plurality of arm portions projecting outward are formed, a notch portion corresponding to the arm portion is formed on the peripheral wall portion of the lens barrel, and the arm portion is pressed with the arm portion and positioned in the notch portion. The peripheral edge of the step lens is on the inner peripheral surface of the lens barrel. Characterized in that it was wearing.

  According to the configuration of the optical system lens of claim 1, when each lens is incorporated in the lens barrel, the cone formed on each lens by being pushed into the lens barrel while pressing the arm portion formed on the last lens. The surfaces are positioned so that the optical axes of the lenses coincide with each other. In this way, the respective lenses are aligned and accommodated in the lens barrel, and the respective lenses are integrated by fixing the peripheral edge of the last lens to the inner peripheral surface of the lens barrel. At this time, the arm portion serving as a pressing margin of the lens is disposed in the cutout portion of the lens barrel, and a dead space due to the pressing margin does not occur in the lens barrel.

  The optical system lens according to claim 2 is characterized in that a fixing means between the last-stage lens and the lens barrel is an adhesive.

  According to the configuration of claim 2, the adhesive is filled between the lens portion peripheral portion formed on the final surface of the lens and the inner peripheral surface of the barrel while pushing the arm portion formed on the last lens. The lenses are integrated and fixed to the lens barrel with the optical axes of the lenses aligned.

  The optical system lens according to claim 3, wherein the last lens has a convex curved lens portion whose final surface bulges to the image side, and a lower portion of the lens portion protrudes from the lens barrel. Features.

  According to the configuration of the third aspect, when the inner diameter dimension of the lens barrel is set to be small, there is a possibility that the outermost light beam directed from the last lens to the imaging device may interfere with the lens barrel. By setting the height of the lens barrel so that the convex curved lens portion that bulges out from the lens barrel, it is possible to prevent interference between the light beam from the lens toward the image sensor and the lens barrel It becomes.

According to the present invention, when assembling to the lens barrel while pressing the last lens in the optical axis direction, for example, by pressing the jig against the arm of the last lens and pushing in the optical axis direction,
Each plastic lens is integrated by aligning the optical axes of each lens with the conical surface of each lens so that they are aligned with each other and fixing the last lens to the lens barrel with an adhesive. Can do. In addition, when inserting each lens into the lens barrel, for the convenience of pressing the last lens in the optical axis direction using a jig or the like, the last lens has a region where the jig is applied to the periphery of the lens portion. Necessary. As this area, the arm part for applying the jig to the outside of the maximum effective diameter of the lens part at the last stage is integrally formed, and a notch part for accommodating the arm part is formed on the peripheral wall part of the barrel corresponding to the arm part This eliminates the need for a dead space for storing the jig in the lens barrel. Thereby, since the inner diameter dimension of the lens barrel can be set small, the outer diameter of the lens barrel can inevitably be set small. In addition, when the inner diameter dimension of the lens barrel is set as small as possible, when a convex curved lens portion that bulges to the image side of the final surface is formed as the last lens, the imaging element from the lens portion There is a possibility that the outermost light beam going to the lens will interfere with the lens barrel, but by setting the height of the lens barrel low, the light beam going from the lens to the image sensor does not interfere with the lens barrel.

1 is a cross-sectional view of an optical system lens showing Example 1. FIG. It is a perspective view of an optical system lens same as the above. It is a bottom view of an optical system lens same as the above. FIG. 4 is a front view in which a part of the optical system lens along the line AA in FIG. 3 is cut out. It is a perspective view of the optical system lens seen from the back side same as the above. It is sectional drawing of the principal part which shows the filling state of an adhesive agent same as the above. It is sectional drawing of the optical system lens which shows a prior art example.

  Embodiments of the present invention will be described below with reference to FIGS. FIG. 1 is a cross-sectional view of an optical system lens according to an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes an optical system lens, and a lens barrel 2 and 4 stored in the lens barrel 2. The first to fourth plastic lenses 4, 5, 6, 7, and between the second and third plastic lenses 5, 6 and between the third and fourth plastic lenses 6, 7. The inner shading plates 8 and 9 are interposed.

  The lens barrel 2 as a whole is perpendicular to an optical axis S integrally formed inwardly from a cylindrical peripheral wall portion 3 that is open at the top and bottom, and a peripheral edge (upper surface side in FIG. 1) of one end opening portion of the peripheral wall portion 3. A threaded portion 30 is formed on the outer peripheral surface of the peripheral wall portion 3 for screwing a holder (not shown). The first to fourth plastic lenses 4, 5, 6, 7 stored in the lens barrel 2 are stored in the lens barrel 2 in a superposed state, of which the second stage from the object side is stored. The second plastic lens 5 is positioned by fitting into a step-like fitting portion 10 formed on the inner peripheral surface of the lens barrel 2, and other plastic lenses 4, 6, 6 excluding the second plastic lens 5. 7 is incorporated in the lens barrel 2 so as to be freely fitted.

  The first plastic lens 4 located at the top is a lens part 4A having convex surfaces on the object side (upper side in the figure) and the image side (lower side in the figure), and a flange shape located outside the maximum effective diameter of the lens part 4A. The edge portion 4B is formed so that the outer diameter of the edge portion 4B is smaller than the inner diameter of the lens barrel 2 and is freely fitted with a clearance between the lens barrel 2 and the clearance. Further, a contact surface 14 that contacts the receiving surface 3a is formed on the object side of the edge portion 4B, an annular protrusion 15 is formed on the image side of the edge portion 4B, and a cone is formed on the outer peripheral surface of the annular protrusion 15. A conical inclined surface 21 is formed in a tapered shape as a surface.

  The second plastic lens 5 located at the second stage is composed of a lens portion 5A having a convex surface on the object side and a concave surface on the image side, and an edge portion 5B located on the periphery of the lens portion 5A. The outer diameter is the same as or slightly larger than the inner diameter of the fitting portion 10 of the lens barrel 2, and the edge portion 5B is fitted to the fitting portion 10 of the lens barrel 2 for positioning. The second plastic lens 5 is formed with annular projections 16 and 17 on the object side and the image side of the edge portion 5B, respectively, and the inner peripheral surface of the object-side annular projection 16 is the first plastic lens. A conical inclined surface 22 having a slight clearance from the conical abutting surface 21 and a conical inclined surface 22 which is the same inclination as the conical inclined surface 21. As shown, a conical contact surface 23 inclined in a tapered shape is formed.

  Similar to the second plastic lens 5, the third plastic lens 6 located in the third stage is composed of a lens portion 6A and an edge portion 6B. The lens portion 6A is different from the second plastic lens 5. Conversely, the object side is concave and the image side is convex. In addition, the outer diameter of the edge portion 6B is smaller than the inner diameter of the lens barrel 2 and is assembled so as to be freely fitted with a clearance between it and the object side and the image side of the edge portion 6B. Are formed on the object side, and the conical abutment surfaces 24 are tapered to the inner peripheral surface of the annular protrusion 18 formed on the object side and the outer peripheral surface of the annular protrusion 19 on the image side, respectively. 25 is formed.

  The fourth plastic lens 7 at the last stage is composed of a lens portion 7A and an edge portion 7B. The lens portion 7A has a concave surface on the object side, an inflection point on the image side, and a continuous concave and convex surface. Yes, and convex as a whole. In addition, the outer diameter of the edge portion 6B is smaller than the inner diameter of the lens barrel 2 and is assembled so as to be freely fitted with a clearance from the lens barrel 2, and an annular protrusion on the object side of the edge portion 7B. The portion 20 is formed, and a conical contact surface 26 inclined in a tapered shape is formed on the inner peripheral surface of the annular protrusion 20. Further, the fourth plastic lens 7 has a plurality of arm portions 35 that are located outside the maximum effective diameter of the lens portion 7A on the final surface and project outward, and are integrally formed at equal intervals. As shown in FIG. 3, three arm portions 35 are integrally formed. The peripheral wall 3 of the lens barrel 2 is formed with a notch 36 that is slightly wider than each arm 35 corresponding to the arm 35, and the fourth plastic lens 7 is inserted into the lens barrel 2. At this time, the arm portion 35 is disposed in the notch portion 36. A light shielding mask 28 is formed on the edge portions 4B-7B of the first to fourth plastic lenses 4-7, and between the light shielding mask 28 and the second and third plastic lenses 5, 6, and The inner light shielding plates 8 and 9 interposed between the third and fourth plastic lenses 6 and 7 function as a diaphragm. Further, the conical inclined surfaces 21 and 22 and the conical contact surfaces 23 to 26 formed on the first to fourth plastic lenses 4 to 7 are conical tapered surfaces centered on the optical axis, respectively. When the fourth plastic lenses 4 to 7 are overlapped with each other, the conical inclined surfaces 21 and 22 and the conical contact surfaces 23 to 26 are fitted to each other to form the first to fourth plastic lenses 4 to 7. The optical axes S are aligned with each other. Further, in the present embodiment, as shown in FIG. 1, the height of the lens barrel 2 is set so that the outermost light ray S <b> 1 directed from the fourth plastic lens 7 at the last stage toward the image sensor 50 does not interfere with the lens barrel 2. Is set low.

  In the present embodiment configured as described above, when the first to fourth plastic lenses 4 to 7 are incorporated into the lens barrel 2, the inner light shielding plate 9 and the first light shielding plate 9 are placed on the fourth plastic lens 7 at the last stage. 3 by sequentially stacking the plastic lens 6, the inner light shielding plate 8, the second plastic lens 5, and the first plastic lens 4, and the conical inclined surfaces 21 and 22 of the first to fourth plastic lenses 4 to 7. The conical contact surfaces 23 to 26 are fitted and positioned. With the first to fourth plastic lenses 4 to 7 positioned as described above, the lens barrel 2 is aligned with the notch portion 36 formed on the peripheral wall portion 3 with the arm portion 35 formed on the fourth plastic lens 7 at the last stage. Insert inside. At this time, the first, third, and fourth plastic lenses 4, 6, and 7 except for the second plastic lens 5 are formed smaller in diameter than the inner diameter of the lens barrel 2, and the second plastic lens 5 is The first plastic lens 4 positioned on the second plastic lens 5 is positioned on the object side of the edge portion 4B by positioning the periphery of the portion 5B with the fitting portion 10 formed on the inner surface of the lens barrel 2. The contact surface 14 to be formed is positioned in contact with the receiving surface 3 a of the lens barrel 2. On the other hand, the third and fourth plastic lenses 6 and 7 located on the rear stage side of the second plastic lens 5 are inserted into the lens barrel 2 while maintaining a clearance from the lens barrel 2, and the first and second plastic lenses 5 and 7 are inserted. In order to fix the third and fourth plastic lenses 6 and 7 including the plastic lenses 4 and 5 to the lens barrel 2, the fourth plastic lens 7 at the last stage is pushed in the optical axis direction and the fourth The plastic lens 7 is fixed to the inner peripheral surface of the lens barrel 2 with an adhesive 40. At this time, a jig (not shown) is abutted against the arm portion 35 formed on the fourth plastic lens 7 and the fourth plastic lens 7 is pressed in the optical axis direction by the jig as shown in FIG. The outer peripheral edge of the fourth plastic lens 7 excluding the arm portion 35 is filled with the adhesive 40 from the nozzle G, and the adhesive 40 is cured, whereby the first to fourth plastic lenses 4 to 7 are the first. Are positioned relative to each other by the conical inclined surfaces 21 and 22 and the conical contact surfaces 23 to 26 formed on the overlapping surfaces of the fourth plastic lenses 4 to 7, and the first to fourth plastic lenses 4 to 7. The optical axis S matches and is fixed to the lens barrel 2 in an aligned state.

As described above, in this embodiment, when pressing the fourth plastic lens 7 located at the last stage in the optical axis direction, a jig (not shown) is abutted against the arm portion 35 of the fourth plastic lens 7. By pushing the fourth plastic lens 7 in the optical axis direction,
Alignment is performed so that the optical axes S of the plastic lenses 4 to 7 are aligned with the lens barrel 2 by the conical inclined surfaces 21 and 22 and the conical contact surfaces 23 to 26, and finally the fourth plastic lens. The plastic lenses 4 to 7 are integrated and fixed to the lens barrel 2 by bonding and fixing 7 to the lens barrel 2. When the plastic lenses 4 to 7 are inserted into the lens barrel 2, while the fourth plastic lens 7 is pushed in the direction of the optical axis and the inner peripheral surface of the lens barrel 2 is filled with the adhesive 40, in the conventional structure, An area where the jig is applied to the peripheral edge of the lens portion 7A of the fourth plastic lens 7 is required, and the inner diameter of the lens barrel 2 needs to be designed including that area. The arm portion 35 for applying a jig to the outside of the maximum effective diameter of the lens portion 7A of the plastic lens 7 is integrally formed, and the arm portion 35 is accommodated in the peripheral wall portion 3 of the barrel 2 corresponding to the arm portion 35. By forming the cutout portion 36, a dead space for storing the jig in the lens barrel 2 becomes unnecessary, and accordingly, the inner diameter dimension of the lens barrel 2 can be set as small as possible. The outer diameter of the lens barrel 2 can be set small. . On the other hand, when the inner diameter of the lens barrel 2 is set to be as small as possible, the outermost light beam S1 from the fourth plastic lens 7 at the last stage toward the image sensor 50 may interfere with the lens barrel 2. However, as shown in FIG. 1, by setting the height of the lens barrel 2 low, the outermost light beam S <b> 1 from the fourth plastic lens 7 at the last stage toward the image sensor 50 is separated from the lens barrel 2. There is no interference.

  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, a basic configuration such as a fitting structure and the number of lenses may be appropriately selected. If a light shielding material is used as the adhesive 40 for fixing the fourth plastic lens 7, the light shielding mask 28 formed on the final surface of the fourth plastic lens 7 can be omitted, and the cost can be reduced. Can do.

DESCRIPTION OF SYMBOLS 1 Optical system lens 2 Lens tube 3 Perimeter wall part 4,5,6,7 Plastic lens 4A, 5A, 6A, 7A Lens part 4B, 5B, 6B, 7B Edge part 21,22 Conical inclined surface (conical surface)
23, 24, 25, 26 Conical contact surface (conical surface)
35 Arm 36 Notch 40 Adhesive 50 Image sensor S Optical axis

Claims (3)

  In a state in which a plurality of lenses composed of a lens portion and an edge portion, a tapered conical surface centered on the optical axis formed on the overlapping surface of the lenses, and the lenses are overlapped A lens barrel for storing and holding, each lens is inserted from an opening of the lens barrel, an outer diameter of the last lens is set smaller than an inner diameter of the lens barrel, and the last lens is optical axis A plurality of arms protruding outward from the periphery of the lens of the last surface of the last lens in an optical system lens that presses in the direction and aligns the optical axes of the lenses with each other by the conical surface of each lens And a notch corresponding to the arm is formed in the peripheral wall of the lens barrel, and the periphery of the lens at the last stage is positioned in the notch while pressing the arm. Light fixed to the inner peripheral surface of System lens.   2. The optical system lens according to claim 1, wherein a fixing means between the last lens and the lens barrel is an adhesive.   The lens of the last stage has a convex curved lens portion whose final surface bulges to the image side, and a lower portion of the lens portion protrudes from the lens barrel. Optical system lens.

Images