JP2012073403A - Lens unit and manufacturing method of lens unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens unit having excellent heat resistance for a reflow treatment and a manufacturing method of the lens unit.SOLUTION: A lens unit comprises a body tube and at least one lens having an optical axis located inside the body tube. The body tube is made from a material which is the same as of the lens and contains a nontransparent coloring material. A manufacturing method of the lens unit comprises the steps of forming the lens from the lens material, holding at least one lens with a holding member and integrally forming a body tube from a resin containing the coloring material to the lens held with the holding member, and detaching the holding member from the lens.

Description

  The present invention relates to a lens unit and a method for manufacturing the lens unit.

  Imaging devices used for mobile phones and surveillance cameras generally form images on solid-state imaging devices such as CCD (Charge Coupled Device) image sensors and complementary metal-oxide semiconductor (CMOS) image sensors and on the light-receiving surface of the solid-state imaging device. And an imaging unit formed integrally with the lens unit.

  Some lens units include a plurality of lenses and a cylindrical lens barrel made of metal or plastic, and a plurality of lenses are accommodated in a lens barrel (see, for example, Patent Document 1).

  As a method for mounting the imaging unit on the circuit board, it is conceivable to employ reflow soldering. In the reflow method, solder is placed in advance on the circuit board board where the parts are mounted, the parts are placed there, the whole circuit board is heated in the reflow tank, and the solder is melted thereby to place the parts on the circuit board. A soldering technique.

  2. Description of the Related Art Conventionally, a lens molded by injection molding or the like using a thermoplastic resin has a problem such as thermal expansion or deformation at a high temperature (about 230 ° C.) of the reflow tank. Could not pass through. For this reason, it is difficult to modularize the lens unit and the solid-state imaging device in the imaging unit first, and it cannot be heated in the reflow tank like other electrical components (integrated circuits, resistors, capacitors, etc.). The efficiency of the manufacturing process could not be improved. Therefore, there is a demand for a lens and a lens unit having excellent heat resistance that do not cause problems even when exposed to high temperatures during reflow soldering.

JP 2009-98614 A

  The present invention provides a lens unit having excellent heat resistance during reflow treatment and a method for manufacturing the lens unit.

A lens unit comprising a lens barrel and at least one lens having an optical axis located inside the lens barrel,
The lens barrel is a lens unit in which a coloring material that does not transmit light is contained in the same material as the lens material formed on the lens.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the lens unit excellent in the heat resistance in the case of a reflow process, and a lens unit can be provided.

It is sectional drawing which shows an example of an imaging unit. It is a figure which shows the lens barrel and the lens integrated in a lens barrel in the lens unit of FIG. It is sectional drawing explaining the procedure of the other manufacturing method of a lens unit. It is sectional drawing explaining the procedure of the other manufacturing method of a lens unit. It is sectional drawing explaining the procedure of the other manufacturing method of a lens unit. It is sectional drawing explaining the procedure of the other manufacturing method of a lens unit. It is sectional drawing explaining the procedure of the other manufacturing method of a lens unit. It is sectional drawing explaining the procedure of the other manufacturing method of a lens unit. It is sectional drawing explaining the procedure of the other manufacturing method of a lens unit. It is sectional drawing explaining the procedure of the other manufacturing method of a lens unit. It is sectional drawing explaining the procedure of the other manufacturing method of a lens unit. It is sectional drawing explaining the procedure of the other manufacturing method of a lens unit.

  FIG. 1 shows an example of an imaging unit.

  The lens unit 10 that constitutes the imaging unit 100 includes a plurality of lenses that constitute an optical system, and a lens barrel 1 that accommodates the plurality of lenses. The plurality of lenses includes a first lens 11 and a second lens 21 in order from the light incident side. The plurality of lenses may be three. Further, one lens may be used.

  The first lens 11 includes a lens portion 12 having optical surfaces on the front and back sides, and a flange portion 13 that spreads around the lens portion 12 in a bowl shape. Similarly, the second lens 21 also includes a lens portion 22 having optical surfaces on the front and back sides, and a flange portion 23 that spreads around the lens portion 22 in a bowl shape.

  The first lens 11 is slightly smaller in diameter than the second lens 21. The first lens 11 and the second lens 21 are held by the lens barrel 1 in a state where the optical axes A of the lens portions 12 and 22 are aligned.

  The lens barrel 1 includes a cylindrical tube portion 2. In this example, the cylindrical portion 2 has a cylindrical shape. One end and the other end in the axial direction of the tube part 2 are open ends. The diameter of one opening end on the light incident side is equal to the diameter of the other opening end. On the inner surface of the barrel 1, two annular fitting portions 1 a and 1 b centering on the central axis of the barrel portion 2 of the barrel 1 are provided. The fitting portion 1a is formed closer to the light incident side than the fitting portion 1b. The inner diameter of the fitting portion 1a is smaller than the inner diameter of the fitting portion 1b.

  The 1st lens 11 is positioned by the internal peripheral surface of the cylinder part 2, and the fitting part 1a. An annular spacer 3 centered on the central axis of the cylindrical portion 2 is attached to the cylindrical portion 2 so as to be fitted to the inner peripheral surface thereof. The spacer 3 contacts the flange portion 13 of the first lens 11 and the flange portion 23 of the second lens 21. The second lens 21 is assembled from the other end of the cylindrical portion 2 and is abutted against the fitting portion 1 b of the cylindrical portion 2. An annular pressing member 6 centering on the central axis of the cylindrical portion 2 is attached to the cylindrical portion 2 so as to be fitted to the inner peripheral surface thereof. The pressing member 6 contacts the flange portion 23 of the second lens 21. The second lens 21 is positioned by the inner peripheral surface of the lens barrel 1, the fitting portion 1 b, and the pressing member 6. Thus, the first lens 11 and the second lens 21 are arranged inside the lens barrel 1 with an interval in the optical axis direction.

  An opening for taking incident light into the first lens 11 is formed at one end of the tube portion 2 of the lens barrel 1. The opening has a circular shape centering on the central axis of the cylindrical portion 2.

  The lens unit 10 is integrated with the sensor 40 by joining the other end of the lens barrel 1 to the substrate 41 of the sensor 40. Light incident on the optical system from one end on the incident side of the lens barrel 1 forms an image on the light receiving surface of the solid-state imaging device 42 of the sensor 40.

  Since the imaging unit 100 uses a lens formed of a resin having reflow resistance as will be described later and is configured with a lens and a lens barrel as described later so that the reflow tank is not damaged by high heat, it is normal. The reflow process can be performed in the same manner as the electronic component. The imaging unit 100 is mounted on the circuit board of the electronic device by reflow processing. Specifically, paste solder is printed in advance on the circuit board at a position where the imaging unit 100 is mounted, and the imaging unit 100 is placed there. The circuit board including the imaging unit 100 is heated at a high temperature of about 200 ° C., and the imaging unit 100 is mounted on the circuit board by melting the solder.

  The lens barrel material forming the lens barrel 1 is a material in which a coloring material that does not transmit light is contained in the same material as the lens material formed on the lens.

  In the imaging unit including this lens unit, the light shielding property of the lens barrel can be ensured, and since the material of each of the lens barrel and the lens is the same, the linear expansion coefficients are substantially equal, and during reflow processing, It is possible to prevent the lens and the lens barrel from being damaged or deformed. Further, when the imaging unit is returned to room temperature after the reflow process, it is possible to prevent the center of the opening of the lens barrel from deviating from the optical axis of the lens. Therefore, the lens unit and the imaging unit are excellent in heat resistance during the reflow process.

Next, the lens material will be described. A resin can be used as the lens material.
In the reflow process, since the entire imaging unit 100 is exposed to high temperature, the resin forming the first lens 11 and the second lens 21 has heat resistance enough to prevent thermal deformation even when exposed to high temperature after curing. 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.

  As for the heat resistance of the resin forming the first lens 11 and the second lens 21, the glass transition temperature of the cured product is preferably 200 ° C. or higher, more preferably 250 ° C. or higher, and 300 ° C. or higher. Is particularly preferred. 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.

  It is preferable that the resin forming the first lens 11 and the second lens 21 has an appropriate fluidity before curing from the viewpoint of moldability such as shape transfer suitability of the mold. Specifically, it is liquid at room temperature and has a viscosity of about 1000 to 50000 mPa · s.

  Further, the resin forming the first lens 11 and the second lens 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, it is desirable that the resin forming the first lens 11 and the second lens 21 be molded from 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.

  Further, in the resin forming the first lens 11 and the second lens 21, it is preferable to disperse the 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 2006-160992 A 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 resin forming the first lens 11 and the second lens 21 may include additives such as known release agents such as silicone-based, fluorine-based, and long-chain alkyl group-containing compounds, and antioxidants such as hindered phenols. May be appropriately blended.

  Moreover, the resin which forms the 1st lens 11 and the 2nd lens 21 can be mix | blended with a curing catalyst or an initiator as needed. 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 first lens 11 and the second lens 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.

  As a lens barrel material for forming the lens barrel, a material in which a coloring material is contained in the same material as the lens material described above is used.

  A black pigment is preferably used as the coloring material. Carbon black is preferably used as the black pigment.

  Next, an example of a method for manufacturing the imaging unit in FIG. 1 will be described. In this embodiment, a thermosetting resin is used for the lens material and the lens barrel material.

  First, the first lens 11 and the second lens 21 are each molded with resin. A mold is used for molding the resin. Although not shown, the mold is composed of a pair of an upper mold and a lower mold, and the resin is cured and molded in a cavity formed by these upper mold and lower mold. In addition, the lens barrel 1 is molded by another mold using a resin in which a coloring material is contained in the same resin as the lens material.

FIG. 2 shows the lens unit 10 of FIG. 1 and shows a state before the lens is assembled into the lens barrel.
After the molding process of the first lens 11 and the second lens 21 and the molding process of the lens barrel 1,
The first lens 11, the spacer 3, the second lens 21, and the pressing member 6 are incorporated into the molded lens barrel 1 in this order. By doing so, the lens unit 10 can be obtained.

  As shown in FIGS. 1 and 2, a groove 4 is preferably formed on the inner diameter surface of the tube portion 2 of the lens barrel 1. The groove 4 is formed on the inner peripheral surface of the cylindrical portion 2 from the fitting portion 1b to the other end of the cylindrical portion 2 and the end surface of the end portion. Although not shown, the spacer 3 has a partial opening so that the groove 4 communicates with the inside of the spacer 3. When the reflow process is performed on the imaging unit 100 including the lens unit 10, the air thermally expanded between the first lens 11 and the second lens 21 can be discharged to the outside of the lens unit 10 through the groove 4. it can.

  Next, another embodiment of the lens unit manufacturing method will be described.

  In the manufacturing method described in this example, a lens unit is obtained by insert-molding a lens barrel in the first lens and the second lens. In the following examples, the above-described lens material is used, and the lens barrel material is the same material as the lens material containing a coloring material.

FIG. 3 shows a cross-sectional view of the first lens, the spacer, and the second lens.
First, the first lens 11 and the second lens 21 formed of resin as in the above example are prepared. The spacer 30 has an annular shape, and annular fitting portions 30 a and 30 b centering on the central axis are formed at both ends in the direction of the central axis of the spacer 30. In the first lens 11, the flange portion 13 is fitted into one fitting portion 30 a of the spacer 30. The second lens 21 has a shape in which the flange portion 23 is fitted into the fitting portion 30 b of the spacer 30, and the flange portion 23 is fitted into the other fitting portion 30 b of the spacer 30. Thus, a lens set M in which the first lens 11 and the second lens 21 are integrally fitted to the spacer 30 is obtained. Here, since the diameter of the flange portion 23 of the second lens 21 is larger than the diameter of the spacer 30, the peripheral surface of the flange portion 23 protrudes to the outer diameter side from the spacer 30.

4 and 5 are cross-sectional views showing a state in which a lens barrel is insert-molded into a lens set.
As shown in FIG. 4, the lens set M is held by the holding member 201. The holding member 201 is a plate-like member and has an annular holding portion 204 erected from the surface thereof. The lens set M is held by fitting the flange portion 23 of the second lens 21 into the holding portion 204.

  Next, a forming die 200 for insert-molding the lens barrel is prepared. The molding die 200 is formed with a molding part S that constitutes a cavity for molding the lens barrel. Further, the mold 200 is formed with a movable portion 202 that advances and retreats with respect to the cavity. The movable part 202 is formed in a columnar shape, and the outer diameter in the circumferential direction corresponds to the opening diameter of the opening formed at one end of the lens barrel.

  As shown in FIG. 4, when the movable portion 202 that has advanced from the mold 200 abuts on the flange portion 13 of the first lens 11 of the lens set M, the lens set M is pressed against the holding member 201. Then, the molding die 200 is placed on the holding member 201 and the lens set M is accommodated in the molding part S. Then, a resin R <b> 1 for forming a lens barrel is injected into the gap between the inner surface of the mold 200 and the holding member 201 and the lens assembly M inside the molding part S of the mold 200.

  As shown in FIG. 5, when the holding member 201 is pushed into the molding part S, the movable part 202 is pushed into the lens set M and retracts into the molding die 200, and the holding member 201 is abutted against the molding die 200 to form the molding. Part S is in a sealed state. At this time, in the molding part S, the movable part 202, the holding member 201, the outer surface of the lens assembly M, and the inner surface of the molding part S form a cavity. Then, the resin R1 is cured by heating the mold 200. The lens barrel 1 is formed by the cured resin R1. Thereafter, the movable part 202 of the molding die 200 is advanced to the molding part S, whereby the molded lens barrel 1, the lens assembly M, and the holding member 201 are taken out from the molding die 200. Next, the holding member 201 is removed from the lens barrel 1 and the lens set M. Thus, the lens unit 10 can be obtained. In the lens unit 10, the diameter of the flange portion 23 of the second lens 21 is configured to be larger than the diameter on the inner peripheral side of the lens barrel 1, so that the lens set M can be removed without dropping from the lens barrel 1. Tightly coupled.

  As shown in FIG. 6, the lens unit 10 is joined to the sensor 40 to complete the imaging unit.

  FIG. 7 is a cross-sectional view showing the configuration of the lens unit. The lens unit 100 includes a lens unit 10 formed by combining a plurality of lens bodies, and a sensor 40. In this example, the lens unit 10 includes a first lens body m1 and a second lens body m2. The number of lens bodies may be three or more, or may be one.

  The first lens body m1 includes a transparent part 51 made of a transparent material that transmits light, and a light shielding part 54 made of an opaque material containing a coloring material in the same material as the transparent material. The part 54 is formed integrally. The transparent part 51 of the first lens body m1 includes a lens part 52 having an optical surface on the front and back sides, and a flange part 53 that spreads around the lens part 52 in a bowl shape. The light shielding portion 54 is formed integrally with the flange portion 53 and is formed in a cylindrical shape having the optical axis of the lens portion 52 as the central axis. Here, a resin having a light transmitting property is used as the transparent material, and a resin containing a coloring material is used as the opaque material.

  The second lens body m2 includes a transparent portion 61 made of a transparent material that transmits light, and a light shielding portion 64 made of an opaque material in which a coloring material is contained in the same material as the transparent material. The part 64 is formed integrally. The transparent part 61 of the second lens body m2 includes a lens part 62 having optical surfaces on the front and back sides, and a flange part 63 that spreads around the lens part 62 in a bowl shape. The light shielding portion 64 is formed integrally with the flange portion 63 and is formed in a cylindrical shape with the optical axis of the lens portion 62 as the central axis.

  FIG. 8 is a cross-sectional view showing a first lens body and a second lens body in the lens unit of FIG.

  An annular fitting portion 54 a centering on the optical axis of the lens portion 52 is formed in the light shielding portion 54 of the first lens body m1. The lens unit 10 is obtained by fitting the flange portion 63 of the transparent portion 61 of the second lens body m2 and the fitting portion 54a of the first lens body m1.

  In the lens unit 10, the optical axis of the lens unit 52 matches the optical axis of the lens unit 62. Further, the diameter of the outer peripheral surface of the light shielding part 54 of the first lens body m1 and the diameter of the inner peripheral surface of the light shielding part 64 of the second lens body m2 are the same. In this example, the light shielding part 54 and the light shielding part 64 form a lens barrel having light shielding properties.

  Next, a procedure for molding the first lens body m1 will be described with reference to FIGS.

  A mold for molding the first lens body m1 includes a lower mold 300, an upper mold 400, and a body mold 500.

  The trunk mold 500 is formed in a cylindrical shape. The lower mold 300 and the upper mold 400 are formed in a cylindrical shape and are inserted into the trunk mold 500. The tip surface of the lower mold 300 and the tip surface of the upper mold 400 are molding surfaces.

  An optical surface molding portion 301 having a shape obtained by inverting one optical surface of the lens portion 52 of the first lens body m1 is formed at a substantially central portion of the molding surface of the lower mold 300, and at a substantially central portion of the molding surface of the upper die 400. An optical surface molding portion 401 having a shape obtained by inverting the other optical surface of the lens portion 52 of the first lens body m1 is formed. A flat portion 302 is formed around the optical surface molding portion 301 on the molding surface of the lower mold 300, and a flat portion 402 is formed around the optical surface molding portion 401 on the molding surface of the upper die 400. The optical surface molding part 301 of the lower mold 300 and the optical surface molding part 401 of the upper mold 400 are both formed in a concave spherical shape obtained by inverting the convex optical surface of the lens part 52 of the first lens body m1. Yes.

  A cylindrical body 303 is formed around the flat portion 302 of the lower mold 300. The cylindrical body forming part 303 is an annular groove part centering on the central axis of the lower mold 300.

  With the lower mold 300 and the upper mold 400 inserted into the trunk mold 500, the cavity is surrounded by the molding surface of the lower mold 300, the molding surface of the upper mold 400, and the inner peripheral surface of the trunk mold 500. It is formed. Resin is molded in this cavity.

  As a procedure for molding the first lens body m1, first, a transparent resin R10 for forming the lens part 52 on the optical surface molding part 301 of the lower mold 300 is supplied. Further, an opaque resin R <b> 20 for forming the light shielding part 54 is supplied to the cylindrical body forming part 303 of the lower mold 300. Each of the resins R10 and R20 is supplied by a predetermined amount corresponding to the volumes of the lens unit 52 and the light shielding unit 54 using a dispenser nozzle (not shown).

  Next, when the upper mold 400 is lowered and the molding surface of the upper mold 400 is pressed against the resin R10 supplied to the lower mold 300, the resin R10 deforms following the molding surface of the upper mold 400 and the molding surface of the lower mold 300. . Then, on the resin R10, the optical surfaces on the front and back of the lens unit 52 are molded by the optical surface molding units 301 and 401 provided on the molding surfaces of the lower mold 300 and the upper mold 400, respectively. Further, the flange portion 53 of the first lens body m1 is molded by the flat portions 302 and 402 of the molding surfaces of the lower mold 300 and the upper mold 400. Further, the resin R <b> 20 is molded into the light shielding unit 54 by the cylindrical body molding unit 303.

  Here, the transparent resin R10 is molded so as to include at least the effective diameter of the lens portion 52. Then, the resin R10 and the resin R20 are molded so that the boundary between the two is located between the effective diameter and the light-shielding portion 54 in a range not included in the effective diameter of the lens portion 52 (described later). The same applies to the resin R10 and the resin R20 of the second lens body m2 to be performed.)

  Heating is performed in a state where the resins R10 and R20 are molded, and the resins R10 and R20 are completely cured.

  Thereafter, the first lens body m1 including the lens part 52 formed of the molded first lens body R10 and the light shielding part 54 formed of the opaque resin R20 can be obtained.

  Next, a procedure for molding the second lens body m2 will be described with reference to FIGS.

  A mold for molding the second lens body m2 includes a lower mold 600, an upper mold 700, and a trunk mold 500.

  The trunk mold 500 is formed in a cylindrical shape. The lower mold 600 and the upper mold 700 are formed in a cylindrical shape and are inserted into the trunk mold 500. The tip surface of the lower mold 600 and the tip surface of the upper mold 700 are molding surfaces.

  An optical surface molding portion 601 having a shape obtained by inverting one optical surface of the lens portion 62 of the second lens body m2 is formed at a substantially central portion of the molding surface of the lower mold 600, and at a substantially central portion of the molding surface of the upper die 700. An optical surface molding portion 701 having a shape obtained by inverting the other optical surface of the lens portion 62 of the second lens body m2 is formed. A flat portion 702 is formed around the optical surface molding portion 701 on the molding surface of the upper mold 700. Both the optical surface molding part 601 of the lower mold 600 and the optical surface molding part 701 of the upper mold 700 are formed in a concave spherical shape obtained by inverting the convex optical surface of the lens part 62 of the second lens body m2. Yes.

  A cylindrical body forming portion 603 is formed around the optical surface forming portion 601 of the lower mold 600. The cylindrical body forming portion 603 is an annular groove portion centering on the central axis of the lower mold 600. Depending on the shape of the flange portion 63 of the second lens body m2, a flat portion is formed around the optical surface molding portion 601 on the molding surface of the mold 600, and a cylindrical molding portion 603 is formed around the flat portion. It may be.

  With the lower mold 600 and the upper mold 700 inserted into the body mold 500, the cavity is surrounded by the molding surface of the lower mold 600, the molding surface of the upper mold 700, and the inner peripheral surface of the body mold 500. It is formed. Resin is molded in this cavity.

  As a procedure for molding the second lens body m2, the lens portion 62 formed of the transparent resin R10 and the opaque resin R20 are formed by a single molding process by the same procedure as the first lens body m1 described above. The 2nd lens body m2 provided with the light-shielding part 64 made can be obtained.

  The lens unit 10 can be obtained by superimposing the first lens body m1 and the second lens body m2 as shown in FIG. The lens unit 10 is joined to the sensor 40 to complete the imaging unit.

In the above example, in the lens unit, the material of the lens barrel is the same material as the lens material formed on the lens, and a coloring material that does not transmit light is included. It was assumed that there were few. However, in the combination of the resin and the coloring material, the linear expansion coefficient may change if the coloring material is contained at a sufficient ratio so that the lens barrel has a sufficient light shielding property. In such a case, there is a difference in the linear expansion coefficient between the lens material and the lens barrel material for the purpose of preventing problems caused by the difference in thermal expansion coefficient between the lens of the lens unit and the lens barrel during the reflow process. It is preferable to select a lens material and a coloring material so as to be 10 × 10 ⁻⁶ or less and to reduce the content of the coloring material.

  The lens unit having such a configuration can be manufactured using a manufacturing method using insert molding shown in FIGS. 3 to 6 or a manufacturing method for molding a plurality of resins shown in FIGS. 7 to 12 in the same process.

The present specification discloses the following matters.
(1) A lens unit comprising a lens barrel and at least one lens having an optical axis located inside the lens barrel,
The lens unit is a lens unit in which a coloring material that does not transmit light is contained in the same material as the lens material formed on the lens.
(2) The lens unit according to (1),
The lens unit, wherein the coloring material is a black pigment.
(3) The lens unit according to (2),
The lens unit, wherein the black pigment is carbon black.
(4) A manufacturing method for manufacturing the lens unit according to any one of (1) to (3),
A method of manufacturing a lens unit, wherein the lens and the lens barrel are separately molded, and then the lens unit is obtained by incorporating the molded lens into the molded lens barrel.
(5) A manufacturing method for manufacturing the lens unit according to any one of (1) to (3),
Molding the lens with a lens material;
Holding the at least one lens on a holding member, and forming the lens barrel integrally with the lens held on the holding member using a resin containing the coloring material;
Removing the holding member from the lens.
(6) A manufacturing method for manufacturing the lens unit according to any one of (1) to (3),
Disposing a transparent material that transmits light and an opaque material containing a coloring material in the same material as the transparent material in the cavity of the mold; and
At least a portion including the effective diameter of the lens has the step of molding the transparent material to obtain the lens, and simultaneously molding the opaque material so as to be integrated with the transparent material to obtain the lens barrel. A manufacturing method of a lens unit.

1 lens barrel 10 lens unit 11 first lens 21 second lens

Claims (6)

A lens unit comprising a lens barrel and at least one lens having an optical axis located inside the lens barrel,
The lens unit is a lens unit in which a coloring material that does not transmit light is contained in the same material as the lens material formed on the lens. The lens unit according to claim 1,
The lens unit, wherein the coloring material is a black pigment. The lens unit according to claim 2,
The lens unit, wherein the black pigment is carbon black. A manufacturing method for manufacturing the lens unit according to any one of claims 1 to 3,
A method of manufacturing a lens unit, wherein the lens and the lens barrel are separately molded, and then the lens unit is obtained by incorporating the molded lens into the molded lens barrel. A manufacturing method for manufacturing the lens unit according to any one of claims 1 to 3,
Molding the lens with a lens material;
Holding the at least one lens on a holding member, and forming the lens barrel integrally with the lens held on the holding member using a resin containing the coloring material;
Removing the holding member from the lens. A manufacturing method for manufacturing the lens unit according to any one of claims 1 to 3,
Disposing a transparent material that transmits light and an opaque material containing a coloring material in the same material as the transparent material in the cavity of the mold; and
At least a portion including the effective diameter of the lens has the step of molding the transparent material to obtain the lens, and simultaneously molding the opaque material so as to be integrated with the transparent material to obtain the lens barrel. A manufacturing method of a lens unit.

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