JP5525985B2 - Lens manufacturing method and manufacturing apparatus - Google Patents

Description

  The present invention relates to a lens manufacturing method and manufacturing apparatus, a lens manufactured by the manufacturing method, and a lens unit including the lens.

  An imaging unit used for a mobile phone or a surveillance camera is generally a sensor unit including a solid-state imaging device such as a CCD (Charge Coupled Device) image sensor or a CMOS (Complementary Metal-Oxide Semiconductor) image sensor, and one or more lenses. And a lens unit including a lens frame that holds the lens and is assembled to the sensor unit. As a lens included in the lens unit, a lens formed of a resin that is inexpensive and excellent in moldability is generally used.

  The above-described imaging unit is mounted on a circuit board such as a mobile phone. However, in order to shorten the mounting process, a reflow process is adopted for mounting the imaging unit. In the reflow process, solder is placed in advance on a circuit board board where components are mounted, the parts are placed there and heated together with the circuit board, thereby melting the solder and soldering the parts to the circuit board. Say the technique.

  In the reflow process, the imaging unit is exposed to a temperature of 200 ° C. or higher. For this reason, heat resistance is also required for the lens of the lens unit, and it is known that the lens is formed of an energy curable resin such as thermosetting or photo-curing (for example, see Patent Document 1). .

  In general, the resin lens is manufactured using a molding die including an upper die and a lower die, and a barrel die surrounding the upper die and the lower die. The resin is deposited in the center of the molding surface of the lower mold, and is sandwiched between the molding surface of the upper mold and the molding surface of the lower mold in the barrel mold as the upper mold descends, and between the molding surfaces It is formed into a lens shape while being unfolded.

  In order to allow the upper and lower molds to be inserted into and removed from the trunk mold, between the inner circumferential surface of the trunk mold and the outer circumferential surface of the upper mold, and between the inner circumferential surface of the trunk mold and the outer circumferential surface of the lower mold Although gaps are provided, the resin may enter these gaps. In particular, the energy curable resin tends to decrease in viscosity once before being cured, and the resin whose viscosity is decreased tends to enter the gap of the mold. When the resin that has entered the gap is cured, mold opening (extraction of the upper mold and the lower mold from the body mold) is hindered. Further, when the cured product remains in the mold, it takes time to remove it, and when it remains as a burr on the lens, the appearance is impaired.

  In Patent Document 2, an energy curable resin containing both a thermal polymerization initiator and a photopolymerization initiator is used, and the viscosity of the resin is increased to some extent by photopolymerization before molding. Describes a technique for preventing the resin from entering the gaps of the molding die by compression molding with, followed by thermal polymerization and curing. However, even with such a technique, there is a possibility that the resin may enter the gaps of the mold due to the pressure applied to the resin during molding.

JP 2009-98614 A JP 2009-126011 A

  The present invention has been made in view of the above-described circumstances, and its purpose is to prevent the resin from entering the gap of the mold for molding the energy curable resin into the lens, and to allow the resin to enter the gap. It is to eliminate various inconveniences caused by it.

(1) A method of manufacturing a lens with an energy curable resin using a mold including an upper mold and a lower mold, and a barrel mold surrounding the upper mold and the lower mold,
A supply step of supplying a part of energy required for curing to the semi-cured state on the molding surface of the lower mold; and
The upper mold and the lower mold are relatively moved in a direction approaching each other until the distance between the molding surface of the upper mold and the molding surface of the lower mold reaches a predetermined distance, and is supplied onto the molding surface of the lower mold. A molding step of sandwiching and molding the resin between the molding surface of the upper mold and the molding surface of the lower mold;
A curing step of supplying and curing energy to the molded resin;
A mold release step for removing the cured resin from the mold, and
The resin supplied in the supplying step is less than the volume of the cavity surrounded by the molding surface of the upper die, the molding surface of the lower die, and the inner peripheral surface of the barrel die, which are set at predetermined intervals in the molding step. The amount of
The method of manufacturing a lens, wherein the resin is a free surface in which a surface facing the inner peripheral surface of the body mold does not contact the body mold over the entire circumference.
(2) A lens manufacturing apparatus made of an energy curable resin, which includes an upper mold and a lower mold each having a molding surface, and a mold that includes a barrel mold surrounding the upper mold and the lower mold, A distance between the molding surface of the upper mold and the molding surface of the lower mold by relatively moving the resin feeding means for feeding the resin onto the molding surface of the lower mold and the upper mold and the lower mold in a direction approaching each other. Drive means with a predetermined interval; and energy supply means for supplying energy to the resin molded between the molding surface of the upper mold and the molding surface of the lower mold, and the resin supply means supplies the semi-cured energy curable resin in an amount less than the volume of the cavity surrounded by the predetermined distance and has been molded surface and the lower mold molding surface of the upper die and the barrel die inner peripheral surface of the Lens manufacturing equipment.

  According to the present invention, it is possible to prevent the resin from entering the gap of the mold. As a result, the mold can be opened smoothly in the mold release process, and the cured product of the resin is prevented from remaining in the mold, eliminating the effort required to remove it and generating burrs on the lens. Can be prevented.

The figure which shows an example of the imaging unit for describing embodiment of this invention. The figure which shows an example of the manufacturing apparatus of the lens for describing embodiment of this invention. The figure which shows the manufacturing method of the lens using the manufacturing apparatus of FIG. The figure which shows the time-dependent change of the viscosity of the resin at the time of heating thermosetting resin. The figure which shows the formation process in the manufacturing method of FIG.

  FIG. 1 shows an example of an imaging unit.

  An imaging unit 1 shown in FIG. 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 to receive a light receiving region on the substrate 10. , Electrodes, insulating films, wirings, and the like are formed.

  The lens unit 3 includes an optical system 4 that includes one or more lenses and a lens barrel 5 that holds the optical system 4. In the illustrated example, the optical system 4 is disposed between the first lens 20 disposed on the incident side, the second lens 21 disposed on the exit side, and the first lens 20 and the second lens 21. It comprises a diaphragm 22. Both the first lens 20 and the second lens 21 are made of a translucent resin. The diaphragm 22 is made of a light-shielding material and is formed of a metal plate such as stainless steel. Note that the configuration of the optical system 4 is not limited to the illustrated example. For example, the number of lenses may be one or three or more, and the diaphragm 22 may be on the incident surface of the first lens 20. You may arrange | position in an appropriate location.

  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 overlapped with the optical axes of the lens portions 30 and 32 being matched.

  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 inner peripheral surface of the fitting portion 34 of the first lens 20 and the outer peripheral surface of the fitting portion 35 of the second lens 21 are tapered surfaces that are aligned with each other. The first lens 20 and the second lens 21 are positioned relative to each other so that the optical axes of the lens portions 30 and 32 coincide with each other by fitting the fitting portions 34 and 35.

  The lens barrel 5 includes a tube portion 40, a lid portion 41 provided at one end portion in the axial direction of the tube portion 40, a pedestal portion 42 provided at the other end portion in the axial direction of the tube portion 40, It is comprised by the pressing member 43 arrange | positioned facing the cover part 41 within the cylinder part 40. As shown in FIG. The lens barrel 5 is made of a light-shielding material, for example, a resin such as a black liquid crystal polymer.

  The optical system 4 is disposed in the cylindrical portion 40 with its optical axis aligned with the central axis of the cylindrical portion 40, sandwiched between the lid portion 41 and the pressing member 43, and held by the lens barrel 5. An opening 44 is provided at the center of the lid 41 through which the optical axis of the optical system 4 passes, and light enters the optical system 4 through the opening 44.

  On the opposing surfaces of the edge portion 31 and the lid portion 41 of the first lens 20 of the opposing optical system 4, fitting portions that are fitted to each other are provided. The fitting portion 36 provided in the edge portion 31 of the first lens 20 is an annular convex portion centered on the optical axis of the optical system 4 (the optical axis of the lens portion 30). Further, the fitting portion 45 provided in the lid portion 41 is an annular convex portion centering on the central axis of the cylindrical portion 40 and is fitted into the fitting portion 36 of the first lens 20. The inner peripheral surface of the fitting portion 36 of the first lens 20 and the outer peripheral surface of the fitting portion 45 of the lid portion 41 are tapered surfaces that are aligned with each other. The optical system 4 is positioned so that its optical axis coincides with the central axis of the cylindrical portion 40 by fitting the fitting portion 36 of the first lens 20 with the fitting portion 45 of the lid portion 41.

  The positioning of the optical system 4 with respect to the lens barrel 5 is performed by fitting the fitting portion 36 of the first lens 20 to the fitting portion 45 of the lid portion 41 as described above. A gap is provided between the outer peripheral surfaces of the first lens 20 and the second lens 21 and the inner peripheral surface of the cylindrical portion 40. This gap absorbs the difference in thermal expansion between the optical system 4 and the lens barrel 5 in a reflow process described later, and relaxes the stress acting on the optical system 4.

  The lens unit 3 is integrated with the sensor unit 2 by joining the pedestal 42 of the lens barrel 5 to the substrate 10 of the sensor unit 2. The light that has entered the optical system 4 through the opening 44 of the lens barrel 5 forms an image on the light 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 after 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, 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.

  Hereinafter, the manufacturing of the lens will be described using the first lens 20 as an example.

  FIG. 2 shows an example of a lens manufacturing apparatus.

  The manufacturing apparatus 100 includes a mold 50, a resin supply unit 101, a drive unit 102, an energy supply unit 103, and a stop unit.

  The molding die 50 includes an upper die 51, a lower die 52, and a body die 53. The trunk mold 53 is formed in a cylindrical shape. The upper mold 51 includes a columnar main body 54 that is inserted into the body mold 53, and a flange 55 that is provided at the base end of the main body 54 and spreads around the main body 54. The flange portion 55 abuts on the axially upper end portion of the trunk mold 53 and defines the amount of insertion of the main body section 54 into the trunk mold 53. Similarly, the lower mold 52 includes a columnar main body 56 that is inserted into the body mold 53, and a flange 57 that is provided at the base end of the main body 56 and spreads in a bowl shape around the main body 56. It is configured. The flange portion 57 is in contact with the lower end portion in the axial direction of the trunk mold 53 and defines the amount of insertion of the main body section 56 into the trunk mold 53. Between the outer peripheral surface of the main body portion 54 of the upper mold 51 and the outer peripheral surface of the main body portion 56 of the lower mold 52 and the inner peripheral surface 64 of the trunk mold 53, the main body portions 54 and 56 are slightly inserted and removed. Each gap is provided.

  The front end surface of the main body portion 54 of the upper mold 51 is a molding surface 60 and has a shape obtained by reversing the surface shape of one of the front and back surfaces of the first lens 20, and a substantially central portion of the molding surface 60 of the upper mold 51. Is provided with an optical surface molding portion 61 having a shape obtained by inverting one optical surface of the lens portion 30 of the first lens 20. The front end surface of the main body portion 56 of the lower mold 52 is also a molding surface 62 and has a shape obtained by inverting the other surface shape of the front and back surfaces of the first lens 20. Is provided with an optical surface molding portion 63 having a shape obtained by inverting the other optical surface of the lens portion 30. The lens portion 30 of the first lens 20 shown in FIG. 1 has a convex spherical optical surface on the incident side and a concave spherical surface on the outgoing side. In the illustrated example, the optical surface of the upper mold 51 is used. The surface molding unit 61 is formed into a convex spherical shape obtained by inverting the optical surface on the emission side, and the optical surface molding unit 63 of the lower mold 52 is molded into a concave spherical shape obtained by inverting the optical surface on the incident side. .

  The main body portion 54 of the upper die 51 and the main body portion 56 of the lower die 52 are respectively placed in the barrel die 53 until the flange portion 55 of the upper die 51 and the flange portion 57 of the lower die 52 are in contact with the end portions of the barrel die 53, respectively. In the inserted state, the distance between the molding surface 60 of the upper mold 51 and the molding surface 62 of the lower mold 52 is equal to the thickness of the first lens 20. A cavity is formed by being surrounded by the molding surface 60 of the upper mold 51, the molding surface 62 of the lower mold 52, and the inner peripheral surface 64 of the body mold 53. The molding mold 50 accommodates the above-described resin in the cavity. Mold.

  For example, a dispenser or the like is used as the resin supply unit 101, and the above-described resin for forming the first lens 20 is quantitatively supplied onto the molding surface 62 of the lower mold 52.

  For example, a press machine or the like is used as the driving unit 102, and at least one of the upper mold 51 and the lower mold 52 is moved to expand and contract the interval between the molding surface 60 of the upper mold 51 and the molding surface 62 of the lower mold 52. In the illustrated example, the lower mold 52 is placed and fixed on the table of the press machine, and the upper mold 51 is attached to the piston of the press machine and moved up and down relative to the lower mold 52.

  The energy supply means 103 supplies curing energy to the resin supplied to the mold 50. The energy supply means 103 is appropriately selected depending on the resin. If the resin is thermosetting, for example, a heat source such as a heater is used. If the resin is photocurable, a light source such as an ultraviolet lamp is used. Is used.

  In FIG. 3, an example of the manufacturing method of the 1st lens 20 using the manufacturing apparatus 100 is shown.

(Supply process)
First, the body 53 is covered with the body 53 of the lower mold 52, and the molding surface 62 of the lower mold 52 is surrounded by the body 53. Then, the resin M is supplied quantitatively to the central portion on the molding surface 62 of the lower mold 52 by the resin supply means 101. Note that after the resin M is supplied onto the molding surface 62 of the lower mold 52, the body mold 53 may be covered with the main body portion 56 of the lower mold 52. (FIG. 3A)

(Molding process)
Next, the upper die 51 is lowered by the driving means 102, and the main body portion 54 of the upper die 51 is inserted into the barrel die 53 until the flange portion 55 contacts the end portion of the barrel die 53. As the main body 54 is inserted, the distance between the molding surface 60 of the upper mold 51 and the molding surface 62 of the lower mold 52 is narrowed, and the resin M is sandwiched between the molding surfaces 60 and 62. Accordingly, the resin M is deformed along the molding surfaces 60 and 62 while being spread between the molding surfaces 60 and 62. The lens portion 30 of the first lens 20 is molded by the optical surface molding portions 61 and 63 provided on both molding surfaces 60 and 62, respectively, and the optical surface molding portions 61 and 63 of the both molding surfaces 60 and 62 are formed. The edge portion 31 of the first lens 20 is molded at the portion other than the portion. (FIG. 3B)

(Curing process)
Next, the energy supply means 103 supplies curing energy E to the molded resin M, and the resin M is cured. When the resin M is a thermosetting resin, the molding die 50 is heated with a heat source such as a heater, and heat is supplied to the resin M through the molding die 50. When the resin M is a photocurable resin, at least one of the upper mold 51, the lower mold 52, and the body mold 53 constituting the mold 50 is formed of a translucent material such as glass. Light is applied to the mold 50 by a light source such as an ultraviolet lamp, and the light is supplied to the resin M through the mold 50. (FIG. 3C)

(Release process)
Next, the upper die 51 is raised by the driving means 102, the main body portion 54 of the upper die 51 is removed from the barrel die 53, and the lens 20 made of the cured resin M is taken out from the molding die 50. The lens 20 can be taken out automatically using, for example, a robot arm. (FIG. 3D)

  Next, the supply process and the molding process in the manufacturing method described above will be described in detail.

  The resin supplied by the resin supply means 101 in the supply process is in a semi-cured state. By supplying a part of the energy required for curing, the resin curing reaction can be stopped halfway and the resin can be semi-cured, and the viscosity of the resin in the semi-cured state depends on the amount of energy supplied at that time Can be prepared. Moreover, if it is an energy curable resin containing both the thermal polymerization initiator and the photopolymerization initiator described in Patent Document 2, the resin is obtained by performing only one of heating or light irradiation on the resin. The resin can be semi-cured, and the viscosity of the resin in the semi-cured state can be adjusted according to the contents of the thermal polymerization initiator and the photopolymerization initiator.

  Here, FIG. 4 shows the change over time in the viscosity of the resin when the thermosetting resin is heated.

In general, the viscosity of a thermosetting resin once becomes smaller than the initial viscosity (viscosity at normal temperature before supplying energy) in the course of curing. Photocurable resins also show a similar tendency. The semi-cured state of the resin described above is preferably a state where the viscosity is greater than the initial viscosity P ₀ via the minimum viscosity P _min . The upper limit of the viscosity of the resin in the semi-cured state may be any viscosity that can be molded, but is about 10,000 mPa · s to 1000000 mPa · s from the viewpoint of moldability.

  The amount of resin supplied by the resin supply means 101 is the same as that of the upper mold 51 when the upper mold 51 is lowered until the flange portion 55 of the upper mold 51 comes into contact with the end of the trunk mold 53 in the molding process. The amount is less than the volume of the cavity surrounded by the molding surface 60 and the molding surface 62 of the lower mold 52 and the inner peripheral surface 64 of the body mold 53.

  FIG. 5 shows the molding process.

  Since the resin M supplied to the central portion on the molding surface 62 of the lower mold 52 by the resin supply means 101 is in a semi-cured state, it does not spread rapidly on the molding surface 62 and the central portion on the molding surface 62. Stay on. As the upper mold 51 is lowered, the resin M is sandwiched between the molding surface 60 of the upper mold 51 and the molding surface 62 of the lower mold 52, and radiates from the center between the molding surfaces 60 and 62. It is spread almost uniformly (FIG. 5A).

  When the flange portion 55 of the upper die 51 comes into contact with the end portion of the barrel die 53, thereafter, the lowering of the upper die 51 is stopped, and the spread of the resin between the molding surfaces 60 and 62 is also stopped. Here, the amount of resin supplied by the resin supply means 101 is an amount less than the volume of the cavity when the upper die 51 is lowered until the flange portion 55 of the upper die 51 comes into contact with the end portion of the barrel die 53. Therefore, the resin M does not contact the inner peripheral surface 64 of the trunk mold 53, and the surface of the resin M facing the inner peripheral surface 64 of the trunk mold 53 is a free surface over the entire circumference. In other words, the air layer A remains in the cavity, and the air layer A is formed by at least the corner portion formed by the molding surface 60 of the upper mold 51 and the inner peripheral surface 64 of the body mold 53 and the molding of the lower mold 52. The corner portion formed by the surface 62 and the inner peripheral surface 64 of the body mold 53 remains over the entire periphery. That is, the gap between the outer peripheral surface of the main body portion 54 of the upper mold 51 and the inner peripheral surface 64 of the trunk mold 53, and the outer peripheral surface of the main body section 56 of the lower mold 52 and the inner peripheral surface 64 of the trunk mold 53. There is no penetration of the resin M into the gaps (FIG. 5B).

  The resin M molded as described above is cured by supplying energy in the curing step. The resin M is in a semi-cured state before energy is supplied in the curing process, and even if the resin M follows the curing process shown in FIG. There is no end. Therefore, a gap between the outer peripheral surface of the main body portion 54 of the upper mold 51 and the inner peripheral surface 64 of the trunk mold 53 and between the outer peripheral surface of the main body section 56 of the lower mold 52 and the inner peripheral surface 64 of the trunk mold 53. These gaps are kept in a state where there is no resin M. Thereby, the mold 50 can be smoothly opened in the mold release process, and the cured product of the resin M is prevented from remaining in the mold, thereby eliminating the time and effort required for the removal. Generation of burrs can be prevented.

  As described above, in the present specification, a method of manufacturing a lens with an energy curable resin using a mold including an upper mold and a lower mold, and a body mold surrounding the upper mold and the lower mold. The step of supplying the resin onto the molding surface of the lower mold and the upper mold and the lower mold until the distance between the molding surface of the upper mold and the molding surface of the lower mold becomes a predetermined distance. A molding process in which the mold is relatively moved in a direction approaching each other, and the resin supplied on the molding surface of the lower mold is sandwiched between the molding surface of the upper mold and the molding surface of the lower mold; A curing step of supplying curing energy to the resin and curing the resin, and a releasing step of taking out the cured resin from the mold. The resin supplied in the supplying step is the molding step. Molding surface of the upper mold and the molding of the lower mold at a predetermined interval Wherein an amount less than the volume of the cavity surrounded by the barrel die inner peripheral surface of the manufacturing method of the lens that is supplied to the semi-cured state is disclosed a portion of the curing energy.

  In the lens manufacturing method disclosed in this specification, in the molding step, the surface of the resin facing the inner peripheral surface of the body mold is a free surface over the entire periphery.

  Further, in the lens manufacturing method disclosed in the present specification, in the molding step, the corner formed by the molding surface of the upper mold and the inner peripheral surface of the barrel mold, and the molding surface of the lower mold, An air layer exists over the entire circumference at the corner formed by the inner peripheral surface of the body mold.

  In the lens manufacturing method disclosed in this specification, the resin supplied in the supplying step has a viscosity of 10,000 mPa · s to 1,000,000 mPa · s.

  Further, the present specification includes an apparatus for manufacturing a lens made of an energy curable resin, and includes an upper mold and a lower mold each having a molding surface, and a body mold surrounding the upper mold and the lower mold. A mold, a resin supply means for supplying the resin on the molding surface of the lower mold, and the upper mold and the lower mold are relatively moved in a direction approaching each other, so that the molding surface of the upper mold and the lower mold are Drive means for setting a distance from the molding surface to a predetermined distance; and energy supply means for supplying curing energy to the resin molded between the molding surface of the upper mold and the molding surface of the lower mold. And the resin supplied by the resin supply means is less than the volume of the cavity surrounded by the molding surface of the upper mold, the molding surface of the lower mold, and the inner peripheral surface of the body mold, which are set at the predetermined interval. Is supplied with some of the curing energy in an amount of Lens manufacturing apparatus is disclosed in the state.

  Further, in the lens manufacturing apparatus disclosed in the present specification, the upper mold has a flange portion that comes into contact with the upper end surface of the trunk mold, and the lower mold is formed on the lower end face of the trunk mold. The upper mold flange surface and the lower mold flange section are in contact with the end surfaces of the barrel mold, respectively, and the upper mold molding surface and the lower mold molding surface The predetermined interval is placed between the two.

  In the lens manufacturing apparatus disclosed in this specification, the viscosity of the resin supplied by the resin supply unit is 10,000 mPa · s to 1000000 mPa · s.

  Further, the present specification discloses a lens manufactured by the above method.

  Further, the present specification includes a lens unit including the lens manufactured by the above method and a lens barrel that holds the lens, and the lens is formed on an edge surface that surrounds the periphery of the optical surface. A lens unit having a fitting portion with the lens barrel is disclosed.

  Further, the present specification includes a plurality of lenses manufactured by the above-described method and a lens barrel that holds the lenses, and the plurality of lenses are stacked in a state in which their optical axes coincide with each other. Each of the plurality of lenses has a fitting portion with an adjacent lens in an edge portion surrounding the periphery of the optical surface. A lens unit is disclosed in which a lens positioned at one end in the direction has a fitting portion with the lens barrel on the edge surface surrounding the periphery of the optical surface.

DESCRIPTION OF SYMBOLS 1 Imaging unit 2 Sensor unit 3 Lens unit 4 Optical system 5 Lens tube 50 Mold 51 Upper mold 52 Lower mold 53 Body mold 100 Manufacturing apparatus 101 Resin supply means 102 Drive means 103 Energy supply means

Claims (5)

A method of manufacturing a lens with an energy curable resin using a mold including an upper mold and a lower mold, and a barrel mold surrounding the upper mold and the lower mold,
A supply step of supplying a part of energy required for curing to the semi-cured state on the molding surface of the lower mold; and
The upper mold and the lower mold are relatively moved in a direction approaching each other until the distance between the molding surface of the upper mold and the molding surface of the lower mold reaches a predetermined distance, and is supplied onto the molding surface of the lower mold. A molding step of sandwiching and molding the resin between the molding surface of the upper mold and the molding surface of the lower mold;
A curing step of supplying and curing energy to the molded resin;
A mold release step for removing the cured resin from the mold, and
The resin supplied in the supplying step is less than the volume of the cavity surrounded by the molding surface of the upper die, the molding surface of the lower die, and the inner peripheral surface of the barrel die, which are set at predetermined intervals in the molding step. The amount of
The method of manufacturing a lens, wherein the resin is a free surface in which a surface facing the inner peripheral surface of the body mold does not contact the body mold over the entire circumference. It is a manufacturing method of the lens according to claim 1 , Comprising:
The said resin supplied at the said supply process is a manufacturing method of the lens whose viscosity is 10000 mPa * s-1 million mPa * s. An apparatus for manufacturing a lens made of energy curable resin,
A mold including an upper mold and a lower mold each having a molding surface, and a barrel mold surrounding the upper mold and the lower mold;
Resin supply means for supplying the resin onto the molding surface of the lower mold;
Driving means for relatively moving the upper mold and the lower mold in a direction approaching each other, and setting a predetermined interval between the molding surface of the upper mold and the molding surface of the lower mold;
Energy supply means for supplying energy to the resin molded by being sandwiched between the molding surface of the upper mold and the molding surface of the lower mold;
With
The resin supply means is a semi-cured energy curing in an amount less than the volume of the cavity surrounded by the molding surface of the upper mold, the molding surface of the lower mold, and the inner peripheral surface of the body mold, which are set at the predetermined interval. Lens manufacturing equipment that supplies resin . The lens manufacturing apparatus according to claim 3 ,
The upper mold has a flange portion that comes into contact with an upper end surface of the trunk mold,
The lower mold has a flange portion that comes into contact with the lower end surface of the trunk mold,
In a state where the upper mold flange portion and the lower mold flange portion are in contact with the end surfaces of the body mold, the predetermined gap is formed between the upper mold forming surface and the lower mold forming surface. Lens manufacturing equipment set. The lens manufacturing apparatus according to claim 3 or 4 ,
The said resin supplied by the said resin supply means is a manufacturing apparatus of the lens whose viscosity is 10000mPa * s-1000000mPa * s.

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