JP2009251302A - Lens unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens unit which is packaged by assembling all components to a holder and soldered in a reflow furnace as it is. <P>SOLUTION: Fitting parts 5 and 6 of first and second lenses 2 and 3 are fit each other and further fitting parts 9 and 10 of the second lens 3 and a lens pressing frame 8 are fit each other, so as to hold the first lens 2 and the second lens 3 between a flange part 7 and the lens pressing frame 8. Focusing of the lens unit 4 is performed by screwing a lens barrel 15 in the holder 40. After a substrate 30 is assembled in the holder 40 to form an imaging module 1, the substrate 30 is soldered in the reflow soldering furnace. Thermal expansion of the first and second lenses 2 and 3 due to heating by soldering is absorbed in gaps (a) and (b) between the lens barrel 15 and the first and second lenses 2 and 3, whereby preventing the first and second lenses 2 and 3 from being in contact with the inner peripheral surface of the lens barrel 15. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a lens unit used for a digital camera or a mobile camera mounted on a mobile phone, and more particularly to a lens unit that can be easily assembled when packaged as a small imaging module.

  In recent years, many photographing functions have been added for mobile phones, and the lens unit mounted on this type of mobile phone's caramel has a plurality of lenses stacked in the optical axis direction in the lens barrel to accommodate high pixels. A structure using a combined lens unit is common.

  By the way, the lens barrel incorporating the lens unit composed of a plurality of lenses in this manner is assembled to the holder, and the substrate on which the holder and the image sensor are mounted is assembled and finally packaged as a small imaging module. It is important that the optical axes of a plurality of lenses constituting the lens unit are positioned and held by the lens barrel without being inclined with respect to the light receiving surface of the image sensor. As a technique for aligning each lens in the optical axis direction and incorporating the lens into the lens barrel, for example, Patent Document 1 discloses a plurality of lenses having different outer diameters and a lens holding portion having a size corresponding to each lens diameter in a stepped shape. A lens barrel device for a lens unit has been proposed in which each lens is incorporated in the lens barrel in order according to the lens diameter. Further, in Patent Document 2, a conical tapered surface that is fitted to each other on the overlapping surface of a plurality of lenses is formed, and the tapered surfaces are fitted to each other so as to align the optical axis direction between the lenses. A method for positioning and fixing the lens is proposed.

  In the lens units proposed in Patent Document 1 and Patent Document 2, since the outer peripheral surface of each lens is fitted into the inner peripheral surface of the lens barrel, alignment between the lenses in the optical axis direction is performed. If there is a gap between each lens on the inner peripheral surface of the cylinder, each lens will move in the radial direction, resulting in eccentricity between the lenses. In the lens unit, the inner diameter of the lens barrel and the outer diameter of each lens are dimensionally controlled with high accuracy so that no gap is formed between the inner peripheral surface of the lens barrel and each lens.

JP 2002-82272 A JP 2006-284788 A

  By the way, the board | substrate used for a small imaging module has mounted many electronic components containing an image pick-up element, and is electrically connected to the conductive pattern formed in the board | substrate by soldering the lead terminal of an electronic component. As a method of soldering the electronic component, it is common to solder the electronic component to the substrate by reflow soldering for the purpose of improving production efficiency by automation. When soldering various electronic components to the board with reflow solder, the electronic parts are transported to the reflow furnace with the electronic components mounted on the board, and the solder is melted by circulating the heating gas in the reflow furnace to solder the electronic parts. Attach. Therefore, in the lens units proposed in Patent Document 1 and Patent Document 2, reflow is performed in a state where a lens barrel in which the lens unit is incorporated and a substrate on which an imaging element is mounted are assembled in a holder and packaged as a small imaging module. It is impossible to solder various electronic components to the board with solder.

  That is, in the conventional small imaging module, a plastic lens that can be easily molded as a material of each lens, and a holder that incorporates a lens barrel that incorporates a lens unit and a substrate that mounts a large number of electronic components including an imaging element, etc. Molded with a synthetic resin different from the lens unit. For this reason, when soldering in a reflow furnace, the lens unit thermally expands and interferes with the lens barrel due to a difference in thermal expansion coefficient between the lens unit and the lens barrel. In other words, as described above, each lens fitted in the inner peripheral surface of the lens barrel is dimensionally controlled with high accuracy so that no gap is generated between the lens barrel and the inner peripheral surface. Since there is no room for thermal expansion in the radial direction inside the lens unit, when the lens unit is thermally expanded and interferes with the lens barrel and the lens unit is strongly pressed against the inner peripheral surface of the lens barrel, deformation and stress occur in the lens. The performance of the lens and the assembly accuracy are significantly reduced. As a result, the focal length between each lens and the image sensor is also distorted, and the optical performance cannot be ensured.

  Therefore, in the past, after mounting only the board with various electronic components assembled to the holder and soldering in the reflow furnace, the lens barrel with the lens assembled is screwed into the holder to adjust the screwing amount of the lens barrel Thus, the focal length between the lens and the image sensor is adjusted, and finally the lens barrel and the holder are bonded and fixed, and finally packaged as a small image pickup module. In such a work process, since the lens barrel is retrofitted, the assembly work to the holder cannot be performed continuously, and thus there is a problem that improvement in efficiency cannot be expected.

  The present invention has been made in view of the above problems, and provides a lens unit that can be soldered in a reflow furnace while all components are assembled and packaged in a holder. Objective.

  The lens unit according to claim 1 is a lens unit in which a plurality of lenses arranged in an optical axis direction are accommodated in a cylindrical barrel, and the lens unit is sandwiched in the optical axis direction in the holder. A pair of lens pressers for holding each lens is provided, and the inner diameter of the lens barrel is larger than the outer diameter of each lens so that a radial gap is provided between the inner periphery of the lens barrel and the outer periphery of each lens. At the same time, a conical fitting portion is formed on the overlapping surface of each lens and centered on the optical axis, and the respective tapered surfaces of the fitting portions are fitted to each other to position each lens in the radial direction. And a conical fitting portion centered on the optical axis and positioned on the overlapping surface of at least one of the lens presser and the lens fixed integrally with the lens barrel. Joint taper Characterized in that was positioned each lens in the radial direction held against the barrel is fitted, respectively.

  According to the lens unit of claim 1, by inserting a plurality of lenses into the lens barrel and fitting the tapered surfaces of the fitting portions formed on the lenses, the optical axes of the lenses are aligned with each other. It is stored in the lens barrel. Since the lens unit housed in the lens barrel is positioned with a gap in the radial direction with respect to the lens barrel in this way, even if the lens unit is thermally expanded, it prevents interference between the lens unit and the lens barrel. be able to.

  The lens unit according to claim 2 is configured by a lens pressing frame in which one of the lens pressers is configured by a flange portion formed in the lens barrel, and the other lens presser is slidably fitted into an inner peripheral surface of the lens barrel. A plurality of lenses constituting the lens unit and the lens pressing frame are sequentially inserted into the lens barrel so that the preceding lens is brought into contact with the flange portion, and the lens pressing frame is pressed against the rearmost lens. The lens holding frame and the lens barrel are fixed integrally after the lenses are positioned and held in the radial direction with respect to the lens barrel.

  According to the lens unit of the second aspect, by inserting a plurality of lenses into the lens barrel and fitting the tapered surfaces of the fitting portions formed on the lenses, the optical axes of the lenses coincide with each other. It is stored in the lens barrel. After that, when the lens holding frame is inserted into the lens barrel, the lens and the tapered surface of the fitting portion formed on the lens holding frame are fitted, and the optical axis of each lens is aligned with the axis of the lens barrel. In addition, the lens unit is sandwiched and held between the flange portion formed on the lens barrel and the lens pressing frame.

  The lens unit according to claim 3 is provided with a holder for assembling the lens barrel and a substrate on which the image pickup device is mounted, and an internal thread portion is formed on an inner peripheral surface of the holder, and the outer periphery of the lens barrel is formed on the female thread portion. After screwing the male screw part formed on the surface, and adjusting the position of the lens unit assembled in the lens barrel in the optical axis direction according to the screwing amount, and focusing the lens unit with respect to the imaging device, Reflow soldering process for electronic components mounted on the substrate in a state where the holder and the lens barrel are integrated, and the lens barrel and the substrate on which the imaging element is mounted are assembled to the holder and packaged as a small imaging module It is characterized by performing.

  According to the lens unit of the third aspect, the small image pickup module is assembled by assembling the lens barrel and the substrate on which the imaging element is mounted to the holder, and is assembled in the lens barrel in accordance with the screwing amount of the lens barrel screwed to the holder. The focal length of the image pickup element and the lens unit is adjusted by adjusting the position of the lens unit in the optical axis direction. Then, the small imaging module is transported to a reflow soldering furnace, and soldering processing of the imaging element and various electronic components assembled on the substrate is performed. At this time, even if the lens unit is thermally expanded due to heating by the soldering process, the lens unit and the lens barrel accommodated in the lens barrel are positioned with a gap in the radial direction. Interference can be prevented.

  5. The lens unit according to claim 4, wherein a gap formed between the lens barrel and each lens prevents interference between each lens and the lens barrel due to thermal expansion of each lens when performing the reflow soldering process. It is characterized by being.

  According to the lens unit of claim 4, when performing soldering processing of the image sensor and various electronic components assembled on the substrate, the lens unit is thermally expanded by being heated at about 250 to 255 ° C. at which the solder melts. Since a gap serving as a clearance for thermal expansion is formed between each lens housed in the cylinder and the lens barrel, each lens does not interfere with the lens barrel.

  The lens unit according to claim 5 is characterized in that the lens pressing frame has a smaller coefficient of thermal expansion than the lens.

  According to the lens unit of the sixth aspect, when performing the soldering process of the image sensor and various electronic components assembled on the substrate, the lens unit and the lens pressing frame are fitted to each other. Since the lens pressing frame has a smaller coefficient of thermal expansion than the lens, the lens fitting portion is separated from the lens pressing frame fitting portion, and the lens does not interfere with the lens pressing frame.

  The lens unit according to claim 6 is characterized in that each of the lenses is made of a plastic material.

  According to the lens unit of the sixth aspect, lens molding is easy.

  The lens unit according to claim 7 is characterized in that the lens unit is mounted on a mobile phone.

  According to the lens unit of the seventh aspect, the lens unit mounted on the mobile phone can be manufactured simultaneously when the module is incorporated.

  According to the lens unit of claim 1, in the lens unit that houses a plurality of lenses arranged in an overlapping manner in the optical axis direction in a cylindrical lens barrel, the lens unit is sandwiched in the optical axis direction and is held in the holder. A pair of lens holders for holding each lens, and the inner diameter of the lens barrel is larger than the outer diameter of each lens so that a radial gap is provided between the inner periphery of the lens barrel and the outer periphery of each lens. And a conical fitting portion centered on the optical axis that is positioned on the overlapping surface of the lenses, and the tapered surfaces of the fitting portions are respectively fitted to each lens in the radial direction. And a conical fitting portion centered on the optical axis located on the overlapping surface of at least one lens presser and the lens fixed integrally with the lens barrel, respectively, Of the mating part Since each lens surface is fitted and positioned in the radial direction with respect to the lens barrel, the lens unit remains in the lens barrel even if the lens unit thermally expands due to heat. The lens unit is housed in the lens barrel with an inner diameter and a gap between the lens unit and the lens barrel to prevent interference between the lens unit and the lens barrel. Degradation of optical performance due to deviation or the like can be prevented.

  According to the lens unit of claim 2, one of the lens pressers is configured by a flange portion formed on the lens barrel, and the other lens presser is slidably fitted on the inner peripheral surface of the lens barrel. The plurality of lenses constituting the lens unit and the lens holding frame are sequentially inserted into the lens barrel so that the preceding lens is brought into contact with the flange portion, and the lens holding frame is used as the last lens. After pressing and positioning and holding each lens in the radial direction with respect to the lens barrel, the lens retaining frame and the lens barrel are integrally fixed. The lens unit can be accurately positioned in the lens barrel in a state where the axis of the lens barrel coincides, and the lens unit is interposed between the flange portion formed on the lens barrel and the lens holding frame. It is possible to fix the lens unit and clamped.

  According to the lens unit of claim 3, a holder for assembling the lens barrel and the substrate on which the image sensor is mounted is provided, and an internal thread portion is formed on the inner peripheral surface of the holder, and the lens barrel is formed on the internal thread portion. The male screw part formed on the outer peripheral surface of the lens unit is screwed, and the lens unit assembled in the lens barrel is adjusted in the optical axis direction according to the screwing amount so that the lens unit is focused on the image sensor. Thereafter, the holder and the lens barrel are integrated, and the reflow soldering of the electronic component mounted on the substrate in a state where the lens barrel and the substrate on which the imaging element is mounted is assembled to the holder and packaged as a small imaging module. Since it is a processing step, there is no need to attach a lens unit to the holder as a retrofit, and a lens unit and a substrate mounted with an image sensor are assembled to the holder as an imaging lens module. Since the soldering process of various electronic components including an imaging element mounted on the substrate by reflow soldering at Kkeji of state it is possible, and productivity is improved, it is possible to reduce the manufacturing cost.

  According to the lens unit of claim 4, a gap formed between the lens barrel and each lens prevents interference between each lens and the lens barrel due to thermal expansion of each lens when performing the reflow soldering process. When the soldering process is performed on various electronic components including the image pickup device mounted on the substrate in a state where the lens unit and the substrate mounted with the image pickup device are assembled in the holder and packaged as an image pickup lens module, the lens unit is mounted on the holder. Will not interfere with the lens barrel even if it expands thermally.

  According to the lens unit of claim 5, since the lens holding frame has a smaller coefficient of thermal expansion than the lens, the lens unit and the substrate on which the imaging element is mounted are assembled in a holder and packaged as an imaging lens module. When soldering the substrate of the image sensor, the lens fitting portion is separated from the lens pressing frame fitting portion, and the lens does not interfere with the lens pressing frame.

  According to the lens unit of claim 6, since each of the lenses is formed of a plastic material, it is easy to mold the lens, and there is a difference between the thermal expansion coefficients of the lens and the lens barrel. Also, the interference between the lens and the lens barrel can be prevented.

  According to the lens unit of claim 7, since the lens unit is mounted on the mobile phone, the productivity of the imaging lens module incorporating the lens unit is improved, thereby reducing the manufacturing cost of the mobile phone. Can be granted.

  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.

  FIG. 1 is a sectional view of an imaging lens module according to an embodiment of the present invention, and FIG. 2 is a sectional view showing an exploded state of the lens unit. In FIG. 1, an imaging lens module 1 includes a lens unit 4 composed of two first lenses 2 and a second lens 3, a lens barrel 15 incorporating the lens unit 4, a lens barrel 15 and a CCD. A holder 40 in which a substrate 30 on which various electronic components including the image sensor 20 are mounted is configured. In addition, the 1st lens 2 and the 2nd lens 3, the lens barrel 15, and the holder 40 which comprise these imaging lens modules 1 are integrally molded products by resin.

  The lens barrel 15 has a male screw portion 16 formed on the outer peripheral surface, and the male screw portion 16 is screwed to a female screw 17 formed on the inner peripheral surface of the holder 40, whereby the lens barrel 15 is attached to the holder 40. Include. At this time, the position of the lens barrel 15 and the lens unit 4 integrally incorporated in the lens barrel 15 can be adjusted in the optical axis direction by the screwing amount of the lens barrel 15, and the optical axis of the lens barrel 15 with respect to the holder 40 can be adjusted. After adjusting the position in the direction, the holder 40 and the lens barrel 15 are integrated by an adhesive.

  The first lens 2 and the second lens 3 inserted into the lens barrel 15 are formed smaller in diameter than the inner periphery of the lens barrel 15, and the outer periphery of the first lens 2 and the second lens 3 and the inner lens 15 Gaps a and b are formed around the circumference. In the lens barrel 15, the first lens 2 and the second lens 3 are movable in the radial direction. For this reason, it is located in the overlapping surface of the 1st lens 2 and the 2nd lens 3, and the conical fitting part 5 centering on the optical axis S at the outer periphery of the 1st lens 2 and the 2nd lens 3 respectively. , 6 are formed, and the tapered surface 6a of the outer peripheral surface of the fitting portion 6 is fitted to the tapered surface 5a of the inner peripheral surface of the fitting portion 5 formed in the first lens 2, whereby the first lens is formed. 2 and the second lens 3 are positioned relative to each other in the radial direction, and are held in a state where the optical axes S of the first lens 2 and the second lens 3 are aligned. Further, as described above, the first lens 2 and the second lens 3 are formed to have a diameter smaller than the inner periphery of the lens barrel 15, and therefore the first lens 2 and the second lens 3 in the lens barrel 15 are In the present embodiment, the first lens 2 and the second lens 3 are clamped and held by a pair of lens pressers in the lens barrel 15 because they can move in the radial direction. This lens presser includes a flange portion 7 formed inward from the front peripheral edge of the lens barrel 15 and a lens presser frame 8 inserted into the lens barrel 15. The first lens 2 and the second lens 2 are provided inside the lens barrel 15. The lens 3 and the lens holding frame 8 are inserted in this order, and the lens holding frame 8 is pressed against the second lens 3 in a state where the previously inserted first lens 2 is abutted against the flange 7. 8, the first lens 2 and the second lens 3 are sandwiched from the front and rear. The presser frame 8 is provided with a protruding protrusion at the periphery with a space therebetween, and the protrusion is press-fitted and held inside the lens barrel 15, and the lens barrel 15 and the lens presser frame 8 are bonded by the adhesive A. Adhere and fix. Further, in order to make the axis of the lens barrel 15 coincide with the optical axes of the first lens 2 and the second lens 3, conical fitting portions 9 centered on the optical axis S are respectively provided on the second lens 3 and the lens holding frame 8. , 10 are respectively formed, and the tapered surface 10a of the outer peripheral surface of the fitting portion 10 of the lens pressing frame 8 is fitted to the tapered surface 9a of the inner peripheral surface of the fitting portion 9 formed on the second lens 3. In this way, the lens holding frame 8 fixed to the lens barrel 15 and the fitting portions 9 and 10 of the second lens 3 are fitted, and the fitting portions of the first lens 2 and the second lens 3 are fitted. By fitting 5 and 6, the first lens 2 and the second lens 3 are fixed to the lens barrel 15 in a state where the optical axes of the first lens 2 and the second lens 3 coincide with the axis of the lens barrel 15. To do. In the present embodiment, a light-shielding diaphragm plate 45 is interposed between the first lens 2 and the second lens 3.

  Further, the gaps a and b between the lens barrel 15 and the first lens 2 and the second lens 3 are determined by the thermal expansion coefficients of the lenses 2 and 3, and are set to about 0.2 mm in this embodiment. That is, in this embodiment, the lenses 2 and 3, the lens barrel 15 incorporating the lenses 2 and 3, and the lens holding frame 8 are integrally formed of different synthetic resins, and the lens barrel 15 excluding the lenses 2 and 3 are The lens pressing frame 8 has substantially the same thermal expansion coefficient, and only the lenses 2 and 3 are larger than the lens barrel 15 and the lens pressing frame 8 in thermal expansion coefficient. The thermal expansion coefficients of the lens barrel 15, the lens holding frame 8 and the holder 40 are approximately 1/10 of the thermal expansion coefficients of the lenses 2 and 3. Various electronic components including the image pickup device 20 are soldered to the substrate 30 by reflow soldering, but the image pickup lens module 1 is packaged, that is, two first lenses 2 and second lenses 3. The lens barrel 15 including the lens unit 4 constituted by the substrate 15 and the substrate 30 are conveyed to the reflow soldering furnace in a state where they are incorporated in the holder 40. During the reflow soldering process, the thermal expansion of the first lens 2 and the second lens 3 due to the heat applied to the first lens 2 and the second lens 3 is the clearance between the lens barrel 15, the first lens 2 and the second lens 3. It is ensured by the gaps a and b.

  In the above-described embodiment configured as described above, first, the first lens 2 is inserted into the lens barrel 15 through the opening of the lens barrel 15, and then the second lens 3 is inserted via the light-shielding diaphragm plate 45. Insert into the lens barrel 15. At this time, by fitting the tapered surface 6a of the fitting portion 6 of the second lens 3 to the tapered surface 5a of the fitting portion 5 formed on the first lens 2, the taper surface 5a of the first lens 2 is aligned. The tapered surface 6a of the second lens 3 is guided, and the optical axes S of the first lens 2 and the second lens 3 coincide with each other. A light-shielding diaphragm plate 45 is provided on the first lens 2 and the second lens 3. It is pinched and held. Further, by inserting the lens pressing frame 8 into the lens barrel 15, the fitting portions 9 and 10 of the second lens 3 and the lens pressing frame 8 are respectively fitted, and the flange portion 7 of the lens barrel 15 and the lens pressing frame are fixed. The first lens 2 and the second lens 3 are sandwiched and held between the frame 8. Thereafter, the lens barrel 15 and the lens holding frame 8 are bonded and fixed, so that the optical axis of the first lens 2 and the second lens 3 and the axis of the lens barrel 15 coincide with each other inside the lens barrel 15. The first lens 2 and the second lens 3 are housed and fixed. Thereafter, the male screw portion 16 formed on the outer peripheral surface of the lens barrel 15 is screwed onto the female screw 17 formed on the inner peripheral surface of the holder 40 to temporarily fix the lens barrel 15 to the holder 40, and to image the holder 40. A substrate 30 on which various electronic components including the element 20 are mounted is assembled into a module. In this way, the amount of screwing of the lens barrel 15 screwed to the holder 40 in a state where the component parts are assembled to the holder 40 is adjusted, and the position of the lens barrel 15 in the optical axis direction with respect to the holder 40 is adjusted to adjust the lens for the image sensor 20. After the unit 4 is focused, the holder 40 and the lens barrel 15 are integrated with an adhesive. Thereafter, the imaging lens module 1 is transported to a reflow soldering furnace, and various electronic components including the imaging element 20 are soldered to the substrate 30. At this time, the imaging lens module 1 is heated to about 250 to 255 ° C. where the solder melts. As described above, when various components are assembled in the holder 40 and packaged as the imaging lens module 1 and soldered in a reflow soldering furnace, the holder 40, the first lens 2, the second lens 3, and the lens barrel 15. However, the lens barrel 15 and the lens holding frame 8 and the first lens 2 and the second lens 3 are made of synthetic resin having different thermal expansion coefficients. The first lens 2 and the second lens 3 are more thermally expanded. However, since gaps a and b serving as clearances for thermal expansion of the first lens 2 and the second lens 3 are formed between the lens barrel 15 and the first lens 2 and the second lens 3, soldering is performed. Even if the first lens 2 and the second lens 3 are thermally expanded by heat applied during processing, they do not hit and interfere with the inner peripheral surface of the lens barrel 15. Further, the fitting portions 9 and 10 of the lens pressing frame 8 fixed to the lens barrel 15 are fitted to each other, but the thermal expansion coefficient of the second lens 3 is larger than that of the lens pressing frame 8. Therefore, in the soldering process, the fitting portion 9 of the second lens 3 is separated from the fitting portion 10 of the lens holding frame 8, and the fitting portion 9 of the second lens 3 is moved by the fitting portion 10 of the lens holding frame 8. It is not pressed outward. Thereby, interference with the 1st lens 2 and the 2nd lens 3, the lens-barrel 15, and the lens holding frame 8 can be prevented in a soldering process. Further, after the soldering process, the cooling process of the imaging lens module 1 is performed, and the fitting portions 9 and 10 of the lens pressing frame 8 fixed to the second lens 3 and the lens barrel 15 in a state where the imaging lens module 1 is cooled. Are fitted again, and the first lens 2 and the second lens 3 are aligned between the optical axis S of the first lens 2 and the second lens 3 and the axis of the lens barrel 15 to coincide with each other between the flange portion 7 of the lens barrel 15 and the lens pressing frame 8. The lens 2 and the second lens 3 can be sandwiched and held.

  As described above, in this embodiment, it is not necessary to attach the lens unit 4 to the holder 40 later, and the imaging lens module 1 is obtained by attaching the lens unit 4 and the substrate 30 on which the imaging element 20 is mounted to the holder 40. With the packaged and the focusing of the imaging device 20 and the lens unit 4 completed, the imaging lens module 1 is transferred to a reflow soldering furnace, and various electronic components including the imaging device 20 are soldered to the substrate 30. Therefore, the production work efficiency is improved, and the production cost can be reduced by improving the production. Further, when the lens unit 4 is soldered in the reflow soldering furnace, the inner peripheral surface of the lens barrel 15 and the lens unit 4 do not interfere even if the first lens 2 and the second lens 3 are thermally expanded in the radial direction. As described above, the gaps a and b in the radial direction are formed between the lens barrel 15 and the first lens 2 and the second lens 3, and the first lens 2 and the second lens 3 are not positioned by the lens barrel 15. Although it is a structure, by fitting the fitting part 5 formed on the first lens 2 and the fitting part 6 of the second lens 3, the optical axes S of the first lens 2 and the second lens 3 are mutually aligned. Further, by fitting the fitting portions 9 and 10 of the lens pressing frame 8 fixed to the second lens 3 and the lens barrel 15, the first lens 2 and the second lens 3 are fitted to the lens barrel 15. The optical axes S are stored in a state of being aligned with each other, and the lens barrel 15 has a flange. Between the parts 7 and the lens presser frame 8 first and second lenses 2 and 3 is sandwiched and held without the lens unit 4 varies. Therefore, the optical performance is not deteriorated by the positional deviation between the first lens 2 and the second lens 3.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design changes are possible. For example, the number of lenses incorporated in the lens barrel, the shape of the holder or the lens barrel, or the shape of the fitting portion formed on the first lens, the second lens, and the presser frame may be appropriately selected. For example, in the embodiment, the first lens 2, the light-shielding diaphragm plate 45, and the second lens 3 are sequentially inserted from the opening of the lens barrel 15, and the lens pressing frame 8 is finally inserted into the lens barrel 15. However, as shown in FIG. 3, the concave portion 49 formed on the surface side of the second lens 3 is formed, and the periphery of the concave portion 49 is fitted with a tapered surface 50a that expands obliquely upward. When the portion 50 is formed and fitted with the tapered surface 50a of the fitting portion 50 and the tapered surface 60a of the fitting portion 60 formed on the back surface side of the first lens 2, the light-shielding diaphragm is formed in the concave portion 49 of the second lens 3. Since the plate 45 can be positioned, the second lens 3, the light-shielding diaphragm plate 45, and the first lens 2 can be sequentially stacked on the lens holding frame 8 to be unitized. Thus, if the second lens 3, the light-shielding diaphragm plate 45, and the first lens 2 are assembled with the lens pressing frame 8 as a reference, the assembly work efficiency is further improved.

It is sectional drawing of the imaging module which shows one Example of this invention. It is sectional drawing of an imaging module which shows a decomposition | disassembly state same as the above. It is sectional drawing of the principal part which shows the modification of a fitting part same as the above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Imaging lens module 2 1st lens 3 2nd lens 4 Lens unit 5,6,9,10,50,60 Fitting part 5a, 6a, 9a, 10a, 50a, 60a Tapered surface 7 Flange part 8 Lens holding frame 15 Lens barrel 20 Image sensor 30 Substrate 40 Holder a, b Gap

Claims (7)

  In a lens unit that houses a plurality of lenses arranged in an overlapping manner in the optical axis direction in a cylindrical barrel, a pair of lenses that hold the lenses in the holder by sandwiching the lens unit in the optical axis direction A presser is provided, the inner diameter of the lens barrel is larger than the outer diameter of each lens, a radial gap is provided between the inner periphery of the lens barrel and the outer periphery of each lens, and the lenses are overlapped. Each of which is formed in a conical fitting portion centered on the optical axis and positioned on the surface, and the respective tapered surfaces of the fitting portions are fitted to position each lens in the radial direction, and the lens barrel and Conical fitting portions are formed on the overlapping surface of at least one of the lens holders and the lens, which are integrally fixed and centered on the optical axis, and the tapered surfaces of the fitting portions are respectively fitted. Combine the mirror Lens unit, wherein the holding and positioning the lenses in the radial direction with respect to the.   One of the lens pressers is configured by a flange portion formed on the lens barrel, and the other lens presser is configured by a lens presser frame that is slidably fitted on the inner peripheral surface of the lens barrel, A plurality of lenses constituting the lens unit and the lens holding frame are sequentially inserted to bring the preceding lens into contact with the flange portion, and the lens holding frame is pressed against the last lens to 2. The lens unit according to claim 1, wherein each lens is positioned and held in the radial direction, and then the lens pressing frame and the lens barrel are integrally fixed.   A holder for assembling the lens barrel and the substrate on which the image sensor is mounted is provided, a female screw portion is formed on the inner peripheral surface of the holder, and a male screw portion formed on the outer peripheral surface of the lens barrel is formed on the female screw portion. After screwing and adjusting the position of the lens unit assembled in the lens barrel in the optical axis direction according to the amount of screwing, and focusing the lens unit with respect to the imaging device, the holder and the lens barrel are integrated. And a reflow soldering process for electronic components to be mounted on the substrate in a state where the lens barrel and the substrate on which the imaging element is mounted are assembled in a holder and packaged as a small imaging module. Item 3. The lens unit according to Item 1 or 2.   The gap formed between the lens barrel and each lens is a gap for preventing interference between each lens and the lens barrel due to thermal expansion of each lens during the reflow soldering process. 3. The lens unit according to 3.   The lens unit according to claim 2, wherein the lens holding frame has a smaller thermal expansion coefficient than the lens.   The lens unit according to claim 1, wherein each of the lenses is made of a plastic material.   The lens unit according to claim 1, wherein the lens unit is mounted on a mobile phone.

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