JP2012073296A - Lens unit, manufacturing method of lens unit, and jig used for the method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens unit that can stably maintain its property even if exposed to a temperature change.SOLUTION: A lens unit includes a plurality of lenses and lens frames holding the plurality of lenses. The plurality of lenses are arranged such that optical axes thereof correspond to each other. The lens frames are sheet members wound to have a radius smaller than outer diameters of the plurality of the lenses. The lens frames have elasticity acting in a direction reducing a roll diameter when the roll diameter is increased. The lens frames cover ranges of the plurality of lenses greater than halves of outer peripheries of the plurality of lenses and are wound around the outer peripheries of the plurality of lenses.

Description

  The present invention relates to a lens unit, a manufacturing method of the lens unit, and a jig used in the manufacturing method.

  Imaging units used in mobile phones and surveillance cameras generally form images on solid-state imaging devices such as CCD (Charge Coupled Device) image sensors and CMOS (Complementary Metal-Oxide Semiconductor) image sensors, and on the light-receiving surface of the solid-state imaging device. And a lens unit. The lens unit includes a plurality of lenses and a lens frame that holds these lenses.

  As a lens included in the lens unit, a lens made of glass or resin having predetermined optical characteristics is generally used. In recent years, lenses made of a resin that is inexpensive and excellent in moldability are frequently used. As the lens frame, a cylindrical member formed of a relatively rigid metal is used. The plurality of lenses are fitted into the lens frame and are held at a predetermined interval in a state where their optical axes coincide with each other.

  The above image pickup unit needs to be connected to the power source, image processing circuit, control circuit, etc. on the camera body side, such as a solid-state image sensor incorporated in the inside, but it is assembled by reflowing this connection process. Since the process can be shortened, there is a strong demand for a lens unit and an imaging unit that can withstand the high temperature of the reflow process. The reflow process is a process in which solder is placed in advance on the circuit board where the component is mounted, the component is placed there, the entire circuit board is heated, the solder is melted, and the component is soldered to the circuit board. Say.

  In the reflow process, the imaging unit is exposed to a temperature of 200 ° C. or higher. The lens formed of resin and the lens frame formed of metal have different coefficients of thermal expansion, and in a high temperature environment in the reflow process, there can be a significant difference between the expansion amounts of the two. As a result, an excessive stress acts on the lens and the lens frame, and the lens and the lens frame may be damaged or deformed.

  A lens unit having a simple and flexible lens frame is also known. For example, a lens unit configured by integrally wrapping the outer periphery of a plurality of lenses positioned with each other with an elastic material or a heat-shrink sleeve. Is known (see, for example, Patent Documents 1 to 3). According to this, it is possible to absorb the difference in thermal expansion between the lens and the lens frame, but it is difficult to firmly hold the plurality of lenses by the lens frame, and the optical axes of the plurality of lenses are misaligned. May occur.

Japanese Utility Model Publication No. 62-118213 Japanese Patent Laid-Open No. 62-153908 JP 2005-17615 A

  The present invention has been made in view of the above-described circumstances, and it is an object of the present invention to provide a lens unit that can stably maintain performance against temperature changes.

(1) A lens unit comprising a plurality of lenses and a lens frame that holds the plurality of lenses, wherein the plurality of lenses are arranged in a state in which their optical axes coincide with each other, A sheet-like member wound to a diameter smaller than the outer diameter of the plurality of lenses, and having elasticity that acts in a direction to reduce the winding diameter when the winding diameter is enlarged, A lens unit that covers a range larger than a half of the outer periphery of the lens and is wound around the outer periphery of the plurality of lenses.
(2) A method of manufacturing a lens unit comprising a plurality of lenses and a lens frame that holds these lenses, wherein the plurality of lenses are arranged in a state in which their optical axes coincide with each other. A plurality of arranged lens frames having elasticity that acts in a direction of reducing the winding diameter when the winding diameter is enlarged. A method of manufacturing a lens unit that covers a range larger than a half of the outer periphery of the lens and winds the lens unit around the outer periphery of the plurality of lenses.

  According to the present invention, with respect to the expansion of a plurality of lenses due to a temperature rise, the lens frame expands to relieve stress acting on each lens. Therefore, deformation and breakage of each lens can be prevented. Then, as the temperature returns to room temperature, the plurality of lenses contract and follow, and the lens frame shrinks due to its elasticity, and continues to hold each lens. Therefore, a plurality of lenses can be firmly held in a state where their optical axes coincide with each other. As described above, the performance of the lens unit can be stably maintained even with respect to temperature changes.

The figure which shows an example of an imaging unit. The figure which shows an example of the lens unit for demonstrating embodiment of this invention. The figure which shows an example of the manufacturing method of the lens unit of FIG. The modification of the lens unit of FIG. 2 is shown. The figure which shows the other example of the lens unit for describing embodiment of this invention. The figure which shows an example of the jig | tool used for manufacture of the lens unit of FIG. The figure which shows an example of the manufacturing method of the lens unit of FIG. The figure which shows the modification of the lens unit of FIG. The figure which shows the other example of the lens unit for describing embodiment of this invention. The figure which shows an example of the jig | tool used for manufacture of the lens unit of FIG. The figure which shows an example of the manufacturing method of the lens unit of FIG.

  FIG. 1 shows an example of an imaging unit, and FIG. 2 shows an example of a lens unit included in the imaging unit.

  The imaging unit 1 includes a sensor unit 2 and a lens unit 3.

  The sensor unit 2 includes a substrate 10 made of a semiconductor such as silicon, and a solid-state image sensor 11 provided at a substantially central portion thereof. The solid-state imaging device 11 is a CCD image sensor or a CMOS image sensor, for example, and repeats a well-known film formation process, photolithography process, etching process, impurity addition process, and the like on the substrate 10, so , Electrodes, insulating films, wirings, and the like are formed.

  The lens unit 3 includes an optical system 4 including a plurality of lenses and a lens frame 5 that holds the optical system 4. In the illustrated example, the optical system 4 includes a first lens 20 disposed on the incident side and a second lens 21 disposed on the emission side. Both the first lens 20 and the second lens 21 are made of a translucent resin and are formed in a circular shape having the same outer diameter d. Note that the configuration of the optical system 4 is not limited to the illustrated example, and the number of lenses may be three or more, for example. Although not shown, the optical system 4 is provided with a stop at an appropriate position of the optical system 4 such as between the first lens 20 and the second lens 21 or on the incident surface of the first lens 20. There is also.

  The first lens 20 includes a lens part 30 having optical surfaces on the front and back sides, and an edge part 31 that spreads around the lens part 30 in a bowl shape. Similarly, the second lens 21 includes a lens part 32 having optical surfaces on the front and back sides and an edge part 33 that spreads around the lens part 32 in a bowl shape. The first lens 20 and the second lens 21 are arranged in a state where the optical axes of the lens portions 30 and 32 are matched.

  The lens frame 5 is a sheet-like member wound in a substantially cylindrical shape, and is wound around the outer periphery of the arranged first lens 20 and second lens 21. In the illustrated example, the length L of the lens frame 5 in the winding direction is larger than the circumferential length of the outer circumference of the first lens 20 and the second lens 21 and smaller than the circumferential length of one round. Therefore, the lens frame 5 covers a range larger than a half circumference of the outer circumferences of the first lens 20 and the second lens 21.

  The lens frame 5 has elasticity that acts in a direction to reduce the winding diameter when the winding diameter is enlarged. In a natural state, in a state where no external force for expanding or reducing the winding diameter acts, the winding diameter (inner diameter) D of the lens frame 5 is smaller than the outer diameter d of the first lens 20 or the second lens 21. Therefore, the lens frame 5 wound around the first lens 20 and the second lens 21 has its winding diameter enlarged from its natural state, exhibits elasticity that acts in the direction of reducing the winding diameter, and the first lens 20. The second lens 21 is held. Thereby, the first lens 20 and the second lens 21 are firmly held in a state where the optical axes are matched.

  The lens unit 3 configured as described above is attached to the sensor unit 2 by joining the edge portion 33 of the second lens 21 to the substrate 10 of the sensor unit 2. The lens unit 3 may be attached to the sensor unit 2 with a ring-shaped spacer interposed between the edge portion 33 of the second lens 21 and the substrate 10. In this state, the lens unit 3 is disposed at a position where the light incident on the optical system 4 forms an image on the image receiving surface of the solid-state imaging device 11 of the sensor unit 2.

  The imaging unit 1 configured as described above is mounted on a circuit board of an electronic device by reflow processing. That is, paste solder is printed in advance on the circuit board at a position where the imaging unit 1 is mounted, and the imaging unit 1 is placed there. The circuit board including the imaging unit 1 is subjected to a heat treatment such as infrared irradiation or hot air blowing, thereby melting the solder and mounting the imaging unit 1 on the circuit board.

  Since the entire imaging unit 1 is heated at the reflow temperature in the reflow process, the resin forming the first lens 20 and the second lens 21 has heat resistance enough to prevent thermal deformation even by the reflow process. As such a resin, an energy curable resin can be used. For example, a thermosetting resin that is cured by heat such as a silicone resin, an epoxy resin, or a phenol resin, or an ultraviolet ray such as an epoxy resin or an acrylic resin. It is possible to use a photo-curable resin that is cured by irradiation.

  Regarding the heat resistance of the resin forming the lenses 20 and 21, the glass transition temperature of the cured product is preferably 200 ° C or higher, more preferably 250 ° C or higher, and particularly preferably 300 ° C or higher. In order to impart such high heat resistance to the resin, it is necessary to constrain the mobility at the molecular level, and effective means include (1) means for increasing the crosslinking density per unit volume, (2 ) Means utilizing a resin having a rigid ring structure (for example, alicyclic structures such as cyclohexane, norbornane, tetracyclododecane, aromatic ring structures such as benzene and naphthalene, cardo structures such as 9,9′-biphenylfluorene, spirobiindane, etc. Resins having a spiro structure, specifically, for example, JP-A-9-137043, JP-A-10-67970, JP-A-2003-55316, JP-A-2007-334018, JP-A-2007-238883, etc. (3) means for uniformly dispersing a substance having a high Tg such as inorganic fine particles (for example, JP-A-5-20902) JP-described), and the like in the 10-298265 Patent Publication. A plurality of these means may be used in combination, and it is preferable to make adjustments within a range that does not impair other characteristics such as fluidity, shrinkage rate, and refractive index characteristics.

  Moreover, it is preferable that the resin forming the lenses 20 and 21 has an appropriate fluidity before curing from the viewpoint of moldability such as the shape transfer suitability of the mold. Specifically, it is liquid at room temperature and has a viscosity of about 1000 to 50000 mPa · s.

  The resin forming the lenses 20 and 21 is preferably a resin having a small volume shrinkage due to the curing reaction from the viewpoint of shape transfer accuracy. The curing shrinkage of the resin is preferably 10% or less, more preferably 5% or less, and particularly preferably 3% or less. Examples of the resin having a low cure shrinkage include (1) resins containing a high molecular weight curing agent (such as a prepolymer) (for example, JP-A Nos. 2001-19740, 2004-302293, and 2007-212147). The number average molecular weight of the high molecular weight curing agent is preferably in the range of 200 to 100,000, more preferably in the range of 500 to 50,000, and particularly preferably in the range of 1,000 to 20,000. The value calculated by the number average molecular weight of the curing agent / number of curing reactive groups is preferably in the range of 50 to 10,000, more preferably in the range of 100 to 5,000. Preferably, it is in the range of 200 to 3,000.), (2) Resins containing non-reactive substances (organic / inorganic fine particles, non-reactive resins, etc.) (Described in JP-A-6-298883, JP-A-2001-247793, JP-A-2006-225434, etc.), (3) Resins containing low-shrinkage crosslinking reactive groups (for example, ring-opening polymerizable groups (for example, epoxy groups ( For example, described in JP-A-2004-210932, etc.), oxetanyl group (for example, described in JP-A-8-134405), episulfide group (for example, described in JP-A-2002-105110), cyclic carbonate Groups (for example, described in JP-A-7-62065) and the like, ene / thiol curing groups (for example, described in JP-A 2003-20334, etc.), hydrosilylation curing groups (for example, JP-A-2005-15666). (4) Resin containing a rigid skeleton resin (fluorene, adamantane, isophorone, etc.) Described in JP-A-137043), and (5) a resin containing two types of monomers having different polymerizable groups to form an interpenetrating network structure (so-called IPN structure) (for example, JP-A-2006-131868) ), (6) Resins containing expansive substances (for example, described in JP-A-2004-2719, JP-A-2008-238417, etc.) and the like, and can be suitably used in the present invention. . In addition, it is preferable from the viewpoint of optimizing physical properties to use a plurality of curing shrinkage reducing means in combination (for example, a prepolymer containing a ring-opening polymerizable group and a resin containing fine particles).

  In addition, the resin forming the lenses 20 and 21 is desirably a mixture of two or more types of resins having different Abbe numbers. The resin on the high Abbe number side preferably has an Abbe number (νd) of 50 or more, more preferably 55 or more, and particularly preferably 60 or more. The refractive index (nd) is preferably 1.52 or more, more preferably 1.55 or more, and particularly preferably 1.57 or more. Such a resin is preferably an aliphatic resin, particularly a resin having an alicyclic structure (for example, a resin having a cyclic structure such as cyclohexane, norbornane, adamantane, tricyclodecane, tetracyclododecane, specifically, for example, JP-A-10-152551, JP-A-2002-212500, JP-A-2003-20334, JP-A-2004-210932, JP-2006-199790, JP-2007-2144, JP-2007-284650. And the resin described in JP-A-2008-105999. The resin on the low Abbe number side preferably has an Abbe number (νd) of 30 or less, more preferably 25 or less, and particularly preferably 20 or less. The refractive index (nd) is preferably 1.60 or more, more preferably 1.63 or more, and particularly preferably 1.65 or more. Such a resin is preferably a resin having an aromatic structure. For example, a resin having a structure such as 9,9′-diarylfluorene, naphthalene, benzothiazole, benzotriazole (specifically, for example, JP-A-60-38411). Publication No. 10-67977, No. 2002-47335, No. 2003-238848, No. 2004-83855, No. 2005-325331, No. 2007-238883, International Publication No. 2006/095610 pamphlet, Japanese Patent No. 2537540, and the like) are preferable.

  In addition, in the resin forming the lenses 20 and 21, it is preferable to disperse inorganic fine particles in the matrix in order to increase the refractive index or adjust the Abbe number. Examples of the inorganic fine particles include oxide fine particles, sulfide fine particles, selenide fine particles, and telluride fine particles. More specifically, for example, fine particles of zirconium oxide, titanium oxide, zinc oxide, tin oxide, niobium oxide, cerium oxide, aluminum oxide, lanthanum oxide, yttrium oxide, zinc sulfide, and the like can be given. In particular, it is preferable to disperse fine particles such as lanthanum oxide, aluminum oxide, and zirconium oxide for the high Abbe number resin, and titanium oxide, tin oxide, zirconium oxide, and the like for the low Abbe number resin. It is preferable to disperse the fine particles. The inorganic fine particles may be used alone or in combination of two or more. Moreover, the composite by several components may be sufficient. In addition, for various purposes such as reducing photocatalytic activity and water absorption, the inorganic fine particles are doped with different metals, the surface layer is coated with different metal oxides such as silica and alumina, silane coupling agents and titanate cups. The surface may be modified with a ring agent, an organic acid (carboxylic acid, sulfonic acid, phosphoric acid, phosphonic acid, etc.) or a dispersant having an organic acid group. The number average particle size of the inorganic fine particles is usually about 1 nm to 1000 nm, but if it is too small, the properties of the substance may change. If it is too large, the influence of Rayleigh scattering becomes remarkable, so 1 nm to 15 nm is preferable. 2 nm to 10 nm are more preferable, and 3 nm to 7 nm are particularly preferable. Further, it is desirable that the particle size distribution of the inorganic fine particles is narrow. There are various ways of defining such monodisperse particles. For example, a numerical value range as described in JP-A No. 2006-160992 applies to a preferable particle size distribution range. Here, the above-mentioned number average primary particle size can be measured by, for example, an X-ray diffraction (XRD) apparatus or a transmission electron microscope (TEM). The refractive index of the inorganic fine particles is preferably 1.90 to 3.00, more preferably 1.90 to 2.70, and more preferably 2.00 to 2.70 at 22 ° C. and a wavelength of 589 nm. It is particularly preferred that The content of the inorganic fine particles with respect to the resin is preferably 5% by mass or more, more preferably 10 to 70% by mass, and particularly preferably 30 to 60% by mass from the viewpoint of transparency and high refractive index.

  In order to uniformly disperse the fine particles in the resin, for example, a dispersant containing a functional group having reactivity with the resin monomer forming the matrix (for example, described in Examples of JP-A-2007-238884), hydrophobic segment And a block copolymer composed of a hydrophilic segment (for example, described in JP-A-2007-2111164), or a resin having a functional group capable of forming an arbitrary chemical bond with inorganic fine particles at the polymer terminal or side chain ( For example, it is desirable to disperse the fine particles by appropriately using JP-A-2007-238929, JP-A-2007-238930, and the like.

  In addition, the resins forming the lenses 20 and 21 are appropriately blended with known release agents such as silicone-based, fluorine-based, and long-chain alkyl group-containing compounds and additives such as antioxidants such as hindered phenols. May be.

  Moreover, a curing catalyst or an initiator can be blended in the resin forming the lenses 20 and 21 as necessary. Specifically, for example, a compound that accelerates a curing reaction (radical polymerization or ionic polymerization) by the action of heat or active energy rays described in JP-A-2005-92099 (paragraph numbers [0063] to [0070]) and the like. Can be mentioned. The amount of addition of these curing reaction accelerators varies depending on the type of catalyst and initiator, or the difference in the curing reactive site, and cannot be specified in general. On the other hand, about 0.1-15 mass% is preferable, and about 0.5-5 mass% is more preferable.

  The resin forming the lenses 20 and 21 can be manufactured by appropriately blending the above components. At this time, if other components can be dissolved in the liquid low molecular weight monomer (reactive diluent), etc., it is not necessary to add a separate solvent, but if this is not the case, use a solvent. A curable resin can be produced by dissolving each component. The solvent that can be used for the curable resin is not particularly limited and may be appropriately selected as long as the composition can be uniformly dissolved or dispersed without precipitation. Specifically, for example, ketones (Eg, acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.), esters (eg, ethyl acetate, butyl acetate, etc.), ethers (eg, tetrahydrofuran, 1,4-dioxane, etc.) alcohols (eg, methanol, ethanol, isopropyl, etc.) Alcohol, butanol, ethylene glycol, etc.), aromatic hydrocarbons (eg, toluene, xylene, etc.), water and the like. When the curable resin contains a solvent, it is preferable to perform molding after drying the solvent.

  The material forming the lens frame 5 also has a heat resistance that does not cause thermal deformation even by reflow processing. Further, the material for forming the lens frame 5 is one that causes the lens frame 5 to exhibit the above-described elasticity, and for example, aluminum, stainless steel, phosphor bronze, spring steel, or an alloy containing at least one of these metals is used. Can do. As a material for forming the lens frame 5, super engineering plastics such as polyether ether ketone, polyphenylene sulfide, liquid crystal polymer, or polyalkylthiophene can also be used.

  Hereinafter, a method for manufacturing the lens unit 3 will be described.

  FIG. 3 sequentially shows the manufacturing process of the lens unit 3.

  On the opposing surfaces of the edge portion 31 of the first lens 20 and the edge portion 33 of the second lens 21 that are opposed to each other, fitting portions that are fitted to each other are provided. The fitting part 34 provided in the edge part 31 of the first lens 20 is an annular convex part centering on the optical axis of the lens part 30. The fitting portion 35 provided on the edge portion 33 of the second lens 21 is an annular convex portion centered on the optical axis of the lens portion 32, and is fitted into the fitting portion 34 of the first lens 20. To do. The first lens 20 and the second lens 21 are positioned with each other by fitting the fitting portions 34 and 35, the optical axes of the lens portions 30 and 32 are aligned, and are arranged at a predetermined interval ( Fig. 3A).

  Then, the diameter of the lens frame 5 is increased so that the winding diameter D of the lens frame 5 is larger than the outer diameter d of the first lens 20 and the second lens 21, and the arranged first lens 20 and second lens 21 are lenses. Insert into the frame 5 (FIG. 3B).

  Then, the force applied to increase the diameter of the lens frame 5 is released, the diameter of the lens frame 5 is reduced by the elasticity of the lens frame 5, and the lens frame 5 is placed on the outer periphery of the first lens 20 and the second lens 21. Wrap. The lens frame 5 holds the first lens 20 and the second lens 21, and the first lens 20 and the second lens 21 are firmly held with their optical axes aligned (FIG. 3C).

  The fitting portion 34 of the first lens 20 and the fitting portion 35 of the second lens 21 are bonded and temporarily fixed, and the lens frame 5 is fixed to the outer periphery of the first lens 20 and the second lens 21 in this state. You may make it wind around.

  In the lens unit 3 described above, the first lens 20 and the second lens 21 and the lens frame 5 are made of different materials, and the first lens 20 and the second lens 21 in which the energy curable resin is used are more metal. Or compared with the lens frame 5 in which super engineering plastic is used, the coefficient of linear expansion is generally large, and the amount of expansion in the radial direction with increasing temperature is also large.

  When the lens unit 3 is exposed to a high temperature environment by a reflow process or the like, the first lens 20 and the second lens 21 expand in the radial direction, and each part of the lens frame 5 is on the inner diameter side by the first lens 20 and the second lens 21. To the outer diameter side. The lens frame 5 is enlarged in diameter, and the first lens 20 and the second lens 21 are allowed to further expand. Thereby, excessive stress does not act on the first lens 20 and the second lens 21, and deformation and breakage of the first lens 20 and the second lens 21 are prevented.

  Then, as the lens unit 3 returns to normal temperature, the first lens 20 and the second lens 21 contract in the radial direction, and the lens frame 5 contracts by its elasticity to follow the first lens 20. 20 and the second lens 21 are held. The first lens 20 and the second lens 21 are firmly held by the lens frame 5 so that their optical axes coincide.

  FIG. 4 shows a modification of the lens unit 3 described above.

  In the lens unit 3a shown in FIG. 4, the length L in the winding direction of the lens frame 5 is made larger than the circumference of one circumference of the outer circumference of the first lens 20 or the second lens 21, and the first lens 20 and the first lens 20 The outer periphery of the two lenses 21 is covered with the lens frame 5 over the entire circumference. The end 5b at the end of winding of the lens frame 5 is overlapped with the end 5a at the beginning of winding, but is not locked to the end 5a at the beginning of winding, and is wound around the end 5a at the beginning of winding. Relative movement is possible in the turning direction. Therefore, the lens frame 5 can elastically expand and contract its winding diameter.

  According to the lens unit 3 configured as described above, it is possible to close the space between the first lens 20 and the second lens 21 and prevent dust or the like from entering the space. Furthermore, if the lens frame 5 is made light-shielding, unnecessary light incident from the outer diameter side of the space between the first lens 20 and the second lens 21 and both lenses can be blocked. When light shielding on the incident surface side of the lens unit 3 is necessary, for example, a light shielding film (black coating) is provided on the edge portion 31 of the first lens 20 or only the lens portion 30 of the first lens 20 is provided. Put on the cap to be exposed.

  FIG. 5 shows another example of the lens unit.

  The lens unit 103 includes an optical system 104 and a lens frame 105 that holds the optical system 104. The optical system 104 includes a first lens 120 and a second lens 121, and the lenses 120 and 121 are arranged with a predetermined interval by interposing a spacer 122 therebetween with their optical axes aligned. It is placed and placed.

  The spacer 122 is formed in an annular shape, and the outer diameter thereof is the same as the outer diameter d of the first lens 120 and the second lens 121, and the edge portion 131 of the first lens 120 and the edge of the second lens 121. It is sandwiched between the part 133. The inner diameter of the spacer 122 is larger than the effective diameter of the lens portion 130 of the first lens 120 and the lens portion 132 of the second lens 121, and is out of the optical path of the optical system 104.

  The lens frame 105 is a sheet-like member wound in a substantially cylindrical shape, and is wound around the outer periphery of the first lens 120 and the second lens 121 that are arranged. In the illustrated example, the length of the lens frame 105 in the winding direction is larger than the circumferential length of the outer circumference of the first lens 120 and the second lens 121 and smaller than the circumferential length of one round. Therefore, the lens frame 105 covers a range larger than a half of the outer circumference of the first lens 120 and the second lens 121.

  The lens frame 105 has elasticity that acts in a direction to reduce the winding diameter when the winding diameter is enlarged, and the winding diameter of the lens frame 105 in the natural state is that of the first lens 120 or the second lens 121. It is smaller than the outer diameter d.

  When the lens unit 103 is exposed to a high temperature environment, the first lens 120 and the second lens 121 expand in the radial direction, but the lens frame 105 expands, and the first lens 120 and the second lens 121 expand further. Is acceptable. Accordingly, excessive stress does not act on the first lens 120 and the second lens 121, and deformation and breakage of the first lens 120 and the second lens 121 are prevented.

  Then, as the lens unit 103 returns to normal temperature, the first lens 120 and the second lens 121 contract in the radial direction, and the lens frame 105 contracts the diameter due to its elasticity. Continue to hold 120 and the second lens 121. The first lens 120 and the second lens 121 are firmly held by the lens frame 105 so that their optical axes coincide.

  Hereinafter, a method for manufacturing the lens unit 103 will be described.

  FIG. 6 shows an example of a jig used for manufacturing the lens unit 103.

  The first lens 120, the second lens 121, and the spacer 122 are arranged using a jig 150. The jig 150 includes three guide bars 151 and a base 152 that holds these guide bars 151. The three guide bars 151 are arranged at equal intervals along the circumference of the diameter d on the base 152 and circumscribed on the circumference, and are erected on the base 152 in parallel with each other. Moreover, it can be attached to and detached from the base 152. In the jig 150 thus configured, the diameter of the inscribed circle of the three guide bars 151 is d, and the diameter of the circumscribed circle is larger than d. Note that the number of guide bars 151 is not limited to three and may be four or more.

  FIG. 7 sequentially shows the manufacturing process of the lens unit 103.

  First, the lens frame 105 is wound around the outer periphery of the three guide bars 151. The diameter of the circumscribed circle of the three guide bars 151 is larger than d, and the lens frame 105 whose natural winding diameter is smaller than d is expanded and develops elasticity acting in the direction of diameter reduction. However, the lens frame 105 is prevented from being reduced in diameter by the three guide bars 151 and maintained at a winding diameter larger than the diameter d (FIG. 7A).

  Next, the first lens 120, the spacer 122, and the second lens 121 are installed on the base 152 in the three guide bars 151 of the jig 150 in this order. The first lens 120, the second lens 121, and the spacer 122 all have the same outer diameter as the diameter d of the inscribed circle of the three guide bars 151, and the first lens 120, the second lens 121, and the spacer. The shaft 122 is fitted in the three guide bars 151 with their axes (in the case of the first lens 120 and the second lens 121) arranged in parallel with the three guide bars 151. Thereby, the first lens 120 and the second lens 121 are arranged with a predetermined interval with the spacer 122 interposed therebetween in a state where their optical axes coincide with each other. At that time, the first lens 120 and the spacer 122, and the second lens 121 and the spacer 122 may be bonded and temporarily fixed (FIG. 7B).

  Next, the three guide bars 151 are pulled out from between the first lens 120 and the second lens 121 and between the spacer 122 and the lens frame 105. By pulling out the three guide bars 151, the lens frame 105 is reduced in diameter by its elasticity, and holds the first lens 120, the second lens 121, and the spacer 122, and the first lens 120 and the second lens 121 are In a state where the optical axes are made coincident, they are firmly held at a predetermined interval (FIG. 7C).

  According to the above manufacturing method, the lens frame 105 can be maintained in an enlarged state by the jig 150, and the first lens 120, the second lens 121, and the spacer 122 can be inserted into the lens frame 105, and The lens frame 105 can be easily wound around the outer periphery.

  FIG. 8 shows a modification of the lens unit 103 described above.

  In the lens unit 103a shown in FIG. 8, the first lens 120 and the second lens 121 are respectively provided with annular convex portions instead of the spacer 122 of the lens unit 103 described above. The convex portion 123 of the first lens 120 is provided on the outer diameter side edge portion of the edge portion 131, and the convex portion 124 of the second lens 121 is provided on the outer diameter side edge portion of the edge portion 133. Yes. The first lens 120 and the second lens 121 are arranged at a predetermined interval by aligning the optical axes using the jig 150 and bringing the convex portions 123 and 124 into contact with each other.

  FIG. 9 shows another example of the lens unit.

  The lens unit 203 includes an optical system 204 and a lens frame 205 that holds the optical system 204. The optical system 204 includes a first lens 220 and a second lens 221, and the two lenses 220 and 221 have a predetermined interval with a spacer 222 interposed therebetween with their optical axes aligned. It is placed and placed.

  The spacer 222 is formed in an annular shape, and the outer diameter thereof is the same as the outer diameter d of the first lens 220 or the second lens 221, and the edge portion 231 of the first lens 220 and the edge of the second lens 221. It is sandwiched between the parts 233.

  A plurality of guide holes that are aligned in the arrangement direction of the first lens 220, the second lens 221, and the spacer 222 are provided in each of the first lens 220, the second lens 221, and the spacer 222. In the illustrated example, the first lens 220, the second lens 221, and the spacer 222 are provided with two guide holes, and the two guide holes 225 of the first lens 220 have a diameter located at the edge portion 231. They are provided on the circumference of d2 at equal intervals in the circumferential direction, and penetrate the edge portion 231 in parallel with the optical axis. The two guide holes 226 of the second lens 221 are also provided on the circumference of the diameter d2 located in the edge portion 233 and at equal intervals in the circumferential direction, and the edge portion 233 is formed in parallel with the optical axis. It penetrates. In addition, the two guide holes 227 of the spacer 222 are provided at locations on the circumference of the diameter d2 that are equally spaced in the circumferential direction, and penetrate the spacer 222 in parallel with the central axis. Note that the number of guide holes provided in each of the first lens 220, the second lens 221, and the spacer 222 is not limited to two, and there may be three or more guide holes. It is good also as a guide groove extended toward those axes from the outer peripheral surface of the 2nd lens 221 and the spacer 222.

  The lens frame 205 is a sheet-like member wound in a substantially cylindrical shape, and is wound around the outer periphery of the first lens 220 and the second lens 221 that are arranged. In the illustrated example, the length of the lens frame 205 in the winding direction is larger than the circumferential length of the outer circumference of the first lens 220 and the second lens 221 and smaller than the circumferential length of one round. Therefore, the lens frame 205 covers a range larger than a half of the outer circumference of the first lens 220 and the second lens 221.

  The lens frame 205 has elasticity that acts in a direction to reduce the winding diameter when the winding diameter is enlarged, and the winding diameter of the lens frame 205 in the natural state is that of the first lens 220 or the second lens 221. It is smaller than the outer diameter d.

  When the lens unit 203 is exposed to a high temperature environment, the first lens 220 and the second lens 221 expand in the radial direction, but the lens frame 205 enlarges the winding diameter, and the first lens 220 and the second lens 221 Further expansion is allowed. Accordingly, excessive stress does not act on the first lens 220 and the second lens 221, and the deformation and breakage of the first lens 220 and the second lens 221 are prevented.

  As the lens unit 203 returns to room temperature, the first lens 220 and the second lens 221 contract in the radial direction, and the lens frame 205 contracts due to its elasticity to follow the first lens 220 and the second lens 221. 220 and the second lens 221 are held. The first lens 220 and the second lens 221 are firmly held by the lens frame 205 so that their optical axes coincide.

  Hereinafter, a method for manufacturing the lens unit 203 will be described.

  FIG. 10 shows an example of a jig used for manufacturing the lens unit 203.

  The first lens 220, the second lens 221, and the spacer 222 are arranged using a jig 250. The jig 250 includes two guide bars 251 as many as the number of guide holes provided in the first lens 220, the second lens 221, and the spacer 222, and a base 252 that holds the guide bars 251. Have. The two guide bars 251 are respectively arranged on the circumference of the diameter d2 on the base 252 and at equal intervals along the circumference, and are erected on the base 252 in parallel with each other. And detachable from the base 252.

  FIG. 11 sequentially shows the manufacturing process of the lens unit 203.

  The first lens 220, the spacer 222, and the second lens 221 are installed on the base 252 of the jig 250 in this order. At that time, the two guide bars 251 of the jig 250 are inserted through the two guide holes of the first lens 220, the second lens 221, and the spacer 222, respectively. Two guide holes of each of the first lens 220, the second lens 221, and the spacer 222 are aligned in the arrangement direction of the first lens 220, the second lens 221, and the spacer 222, and accordingly, the first lens 220 and the second lens 222 are aligned. The two lenses 221 are arranged at a predetermined interval with a spacer 222 interposed therebetween with the optical axes thereof aligned (FIG. 11A).

  Then, the diameter of the lens frame 205 is expanded so that the winding diameter of the lens frame 205 is larger than the outer diameter d of the first lens 220 and the second lens 221, and the arranged first lens 220 and second lens 221 and spacer 222. Is inserted into the lens frame 205. Then, the force applied to increase the diameter of the lens frame 205 is released, the diameter of the lens frame 205 is reduced by the elasticity of the lens frame 205, and the lens frame 205 is moved to the first lens 220, the second lens 221, and the spacer 222. Wrap around the circumference of the. The two guide bars 251 are accommodated in a plurality of guide holes aligned in the arrangement direction of the first lens 220, the second lens 221, and the spacer 222, and the first lens 220, the second lens 221, the spacer 222, The lens frame 205 is in close contact with the outer peripheral surfaces of the first lens 220, the second lens 221, and the spacer 222 without being interposed between the lens frame 205 and the lens frame 205. The lens frame 205 grips the first lens 220 and the second lens 221, and the first lens 220 and the second lens 221 are firmly held with their optical axes aligned (FIG. 11B).

  Next, the two guide bars 251 are pulled out from the guide holes of the first lens 220 and the second lens 221 and the spacer 222. As described above, the two guide bars 251 are not sandwiched between the first lens 220, the second lens 221, and the spacer 222 and the lens frame 205, and these guide bars 251 can be easily pulled out. (FIG. 11C).

  In addition, although it demonstrated as what pulls out the two guide bars 251, these guide bars 251 are accommodated in the group of several guide holes aligned in the sequence direction of the 1st lens 220, the 2nd lens 221, and the spacer 222. Therefore, the close contact of the lens frame 205 with the outer peripheral surfaces of the first lens 220, the second lens 221, and the spacer 222 is not hindered. Therefore, each guide bar 251 may be separated from the base 252 and left in the lens unit 203. In that case, both ends of each guide bar 251 protruding from the lens unit 203 may be cut off. Also, one end of each guide bar 251 protruding from the lens unit 203 is left in a state protruding from the lens unit 203, and the end of each guide bar 251 is used as the substrate 10 of the sensor unit 2 (see FIG. 1). It is also possible to attach the lens unit 203 to the sensor unit 2 by bonding to the sensor unit 2.

  As described above, the present specification includes a lens unit that includes a plurality of lenses and a lens frame that holds the plurality of lenses, and the optical axes of the plurality of lenses coincide with each other. The lens frame is a sheet-like member wound to a diameter smaller than the outer diameter of the plurality of lenses, and acts in a direction to reduce the winding diameter when the winding diameter is increased. There is disclosed a lens unit that has elasticity and covers a range larger than a half of the outer periphery of the plurality of lenses and is wound around the outer periphery of the plurality of lenses.

  In the lens unit disclosed in this specification, each of the plurality of lenses is provided with a fitting portion with an adjacent lens.

  In the lens unit disclosed in this specification, each of the plurality of lenses is provided with a plurality of guide holes or guide grooves that are aligned in the arrangement direction thereof.

  In the lens unit disclosed in this specification, the lens frame covers the outer circumferences of the plurality of lenses over the entire circumference.

  In the lens unit disclosed in the present specification, the lens frame is light-shielding.

  In the lens unit disclosed in the present specification, the heat resistance temperature of the plurality of lenses and the lens frame is 200 ° C. or higher.

  In the lens unit disclosed in the present specification, the lens frame is made of one metal selected from the group consisting of aluminum, stainless steel, phosphor bronze, and spring steel, or an alloy containing the metal.

  In the lens unit disclosed in the present specification, the lens frame is made of one resin selected from the group consisting of polyetheretherketone, polyphenylene sulfide, liquid crystal polymer, and polyalkylthiophene.

  Further, the present specification provides a method of manufacturing a lens unit including a plurality of lenses and a lens frame that holds these lenses, wherein the plurality of lenses are in a state in which their optical axes coincide with each other. A sheet-like member arranged and wound around a diameter smaller than the outer diameter of the plurality of lenses, the lens frame having elasticity acting in a direction to reduce the winding diameter when the winding diameter is enlarged, A method of manufacturing a lens unit that covers a range larger than a half of the outer periphery of a plurality of lenses and wraps around the outer periphery of the plurality of lenses is disclosed.

  In the method of manufacturing a lens unit disclosed in the present specification, each of the plurality of lenses is provided with a fitting portion with an adjacent lens, and each fitting portion of the plurality of lenses is adjacent to the lens. The lenses are fitted with fitting portions of matching lenses so that the optical axes of the plurality of lenses coincide with each other.

  Further, in the lens unit manufacturing method disclosed in the present specification, a plurality of guide bars along the arrangement direction of the plurality of lenses are engaged with the plurality of lenses, respectively, and the optical axes of the plurality of lenses coincide with each other. Let

  The lens unit manufacturing method disclosed in the present specification uses three or more guide bars, and these guide bars are arranged on the outer peripheral surface of each of the plurality of lenses at equal intervals in the circumferential direction. And contact.

  In the lens unit manufacturing method disclosed in the present specification, each of the plurality of lenses is provided with a plurality of guide holes or guide grooves aligned in the arrangement direction thereof, and the plurality of lenses aligned in the arrangement direction are provided. The guide bars are inserted through the guide holes or groups of guide grooves.

  Further, the present specification discloses a jig used in the above-described method of manufacturing a lens unit, the jig including the plurality of guide bars and a base for holding these guide bars. .

DESCRIPTION OF SYMBOLS 1 Imaging unit 2 Sensor unit 3 Lens unit 4 Optical system 5 Lens frame 10 Board | substrate 11 Solid-state image sensor 20 1st lens 21 2nd lens

Claims (14)

A lens unit comprising a plurality of lenses and a lens frame that holds the plurality of lenses,
The plurality of lenses are arranged so that their optical axes coincide with each other,
The lens frame is a sheet-like member wound to a diameter smaller than the outer diameter of the plurality of lenses, and has an elasticity that acts in a direction of reducing the winding diameter when the winding diameter is increased. A lens unit wound around the outer periphery of the plurality of lenses so as to cover a range larger than a half of the outer periphery of the plurality of lenses. The lens unit according to claim 1,
A lens unit in which each of the plurality of lenses is provided with a fitting portion with an adjacent lens. The lens unit according to claim 1,
A lens unit in which each of the plurality of lenses is provided with a plurality of guide holes or guide grooves aligned in the arrangement direction thereof. The lens unit according to any one of claims 1 to 3,
The lens frame is a lens unit that covers the outer circumferences of the plurality of lenses over the entire circumference. The lens unit according to claim 4,
The lens frame is a lens unit having a light shielding property. The lens unit according to any one of claims 1 to 5,
The lens unit in which the heat-resistant temperature of the plurality of lenses and the lens frame is 200 ° C. or higher. The lens unit according to claim 6,
The lens frame is a lens unit made of one metal selected from the group consisting of aluminum, stainless steel, phosphor bronze, and spring steel, or an alloy containing the metal. The lens unit according to claim 6,
The lens frame is a lens unit made of one kind of resin selected from the group consisting of polyetheretherketone, polyphenylene sulfide, liquid crystal polymer, and polyalkylthiophene. A method of manufacturing a lens unit comprising a plurality of lenses and a lens frame that holds these lenses,
Arranging the plurality of lenses in a state in which their optical axes coincide with each other;
A sheet-like member wound to a diameter smaller than the outer diameter of the plurality of lenses, and having a lens frame having elasticity acting in a direction to reduce the winding diameter when the winding diameter is enlarged, the plurality of lenses A method of manufacturing a lens unit that covers a range larger than a half of the outer circumference of the lens and winds it around the outer circumference of the plurality of lenses. It is a manufacturing method of the lens unit according to claim 9,
Each of the plurality of lenses is provided with a fitting portion with an adjacent lens,
A manufacturing method of a lens unit in which each fitting portion of each of the plurality of lenses is fitted with a fitting portion of an adjacent lens, and the optical axes of the plurality of lenses are aligned with each other. It is a manufacturing method of the lens unit according to claim 9,
A method of manufacturing a lens unit, wherein a plurality of guide bars along an arrangement direction of the plurality of lenses are engaged with the plurality of lenses, respectively, and optical axes of the plurality of lenses are aligned with each other. It is a manufacturing method of the lens unit according to claim 11,
A method for manufacturing a lens unit, comprising using three or more guide bars and contacting these guide bars with the outer peripheral surface of each of the plurality of lenses at equal intervals in the circumferential direction. It is a manufacturing method of the lens unit according to claim 11,
Each of the plurality of lenses is provided with a plurality of guide holes or guide grooves aligned in the arrangement direction thereof.
A method of manufacturing a lens unit, wherein the guide bar is passed through a group of the guide holes or guide grooves aligned in the arrangement direction. A jig used in the method of manufacturing a lens unit according to any one of claims 11 to 13,
A jig comprising the plurality of guide bars and a base for holding these guide bars.

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