JP2011138087A - Lens array - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens array that secures bonding strength between a lens and a substrate regardless of lens shape. <P>SOLUTION: The lens array 5 includes: the substrate 30 formed of inorganic material; and a plurality of lenses 32 formed of a resin material and provided by filling up each of a plurality of through-holes 34 arranged on the substrate 30. An inner peripheral surface of the through-hole 34 is subjected to surface treatment with a coupling agent. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a lens array.

  In recent years, portable terminals of electronic devices such as mobile phones and PDAs (Personal Digital Assistants) are equipped with small and thin imaging units. Such an imaging unit generally includes 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 that form a subject image on the solid-state imaging device. And.

  With the downsizing / thinning of portable terminals and the widespread use of portable terminals, further reduction in size / thinning is required for imaging units mounted on the portable terminals, and productivity is required. In response to such a request, one or more lens arrays in which a plurality of lenses are arrayed are sequentially stacked on a sensor array in which a plurality of solid-state image sensors are arrayed, and the obtained stacked bodies are respectively combined with a solid-state image sensor and a lens. A method of mass-producing an imaging unit by cutting so as to include

  As a lens array used for the above applications, a curable resin material is dropped onto the surface of a parallel plate substrate made of a light-transmitting material such as glass, and the resin material is molded into a predetermined shape using a mold. It is known that a plurality of lenses are formed by curing in such a state (see, for example, Patent Documents 1 and 2). However, in the lens array having such a configuration, the lens includes a portion made of a curable resin material and a portion made of a substrate material having optical characteristics different from that of the curable resin material, and reflection occurs at the boundary between them. As a result, inconveniences in optical characteristics such as flare and ghost are generated and image quality is deteriorated.

  Another lens array is known in which a plurality of through holes are formed in a substrate made of a semiconductor such as silicon or a metal, a resin material is disposed in each of the through holes, and a lens is formed of the resin material ( For example, see Patent Document 3). According to the lens array having such a configuration, the lens is formed of only a resin material, there is no boundary between materials having different optical characteristics, and flare and ghost can be prevented from occurring.

Japanese Patent No. 3926380 International Publication No. 08/102648 International Publication No. 09/077670

  In the lens array described in Patent Document 3, in order to ensure the bonding strength between the lens and the substrate, the lens is provided with a bowl-shaped base layer that overlaps the surface of the substrate around the through hole. However, depending on the lens shape, it may be difficult to provide the base layer. For example, the case where the whole lens is accommodated in a through-hole etc. for low profile is mentioned. In such a case, the lens array described in Patent Document 3 has a disadvantage that the bonding strength between the lens and the substrate cannot be secured.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a lens array in which the bonding strength between the lens and the substrate is ensured regardless of the lens shape.

A lens array comprising: a substrate formed of an inorganic material; and a plurality of lenses formed of a resin material and provided by filling each of the plurality of through holes arranged in the substrate,
A lens array in which an inner peripheral surface of the through hole is surface-treated with a coupling agent.

  According to the present invention, the adhesion with the resin material on the inner peripheral surface of the through hole is improved by the surface treatment with the coupling agent. Thereby, the bonding strength between the substrate formed of the inorganic material and the lens formed of the resin material is ensured.

It is a figure which shows an example of an imaging unit for describing embodiment of this invention. It is a figure which shows an example of a lens array for describing embodiment of this invention. It is a figure which shows the lens array of FIG. 2 in the III-III line cross section. 4A to 4H are diagrams showing modifications of the lens array in FIG. 5A to 5D are diagrams illustrating an example of a method of manufacturing a substrate included in the lens array of FIG. It is a figure which shows an example of the shaping | molding die which forms the lens of the lens array of FIG. 7A to 7C are diagrams illustrating an example of a manufacturing method of the lens array of FIG. It is a figure which shows the modification of the manufacturing method of the lens array shown to FIG. 7A-FIG. 7C. 9A and 9B are diagrams illustrating an example of a method for manufacturing the imaging unit of FIG. 10A to 10C are diagrams showing a modification of the method for manufacturing the imaging unit shown in FIGS. 9A and 9B. 11A and 11B are diagrams illustrating another example of a method for manufacturing the imaging unit in FIG. 12A to 12C are diagrams showing a modification of the method for manufacturing the imaging unit shown in FIGS. 11A and 11B.

  FIG. 1 shows an example of an imaging unit.

  As shown in FIG. 1, the imaging unit 1 includes a sensor module 2 including a solid-state imaging element 22 and a lens module 3 including a lens 32 that forms a subject image in a light receiving region of the solid-state imaging element 22. .

  The sensor module 2 has a wafer piece 21. The wafer piece 21 is formed of a semiconductor such as silicon, for example, and has a substantially rectangular shape in plan view. A solid-state image sensor 22 is provided at a substantially central portion of the wafer piece 21. The solid-state imaging device 22 is, for example, a CCD image sensor, a CMOS image sensor, or the like, and repeats a well-known film formation process, photolithography process, etching process, impurity addition process, etc. A light receiving region, an electrode, an insulating film, a wiring, and the like are formed.

  The lens module 3 includes a substrate piece 31 and a lens 32. The substrate piece 31 is formed in a substantially rectangular shape in plan view that is substantially the same as the wafer piece 21 of the sensor module 2. A through hole 34 having a substantially circular shape in plan view that penetrates the substrate piece 31 in the thickness direction is formed in the central portion of the substrate piece 31. The lens 32 is provided so as to fill the through hole 34 and is supported by the substrate piece 31. The lens surfaces 33 respectively formed at both ends of the optical axis direction of the lens 32 are convex spherical surfaces in the illustrated example. However, depending on the application, convex spherical surfaces, concave spherical surfaces, aspherical surfaces, Or various combinations of planes can be taken.

  On one surface of the substrate piece 31 (the lower surface in the figure), a leg portion 35 is projected. The leg portion 35 protrudes from the surface of the substrate piece 31 higher than the surface of the lens 32 exposed on the surface side of the substrate piece 31 on which the leg portion 35 is provided. The lens module 3 is laminated on the sensor module 2 by joining the leg portions 35 of the substrate piece 31 to the wafer piece 21 of the sensor module 2. The height H of the leg portion 35 from the surface of the substrate piece 31 provided with the leg portion 35 is set so that the lens 32 does not contact the sensor module 2. That is, the height H of the leg portion 35 from the surface of the substrate piece 31 is H> h with respect to the height h of the lens 32 from the surface of the substrate piece 31.

  As long as the lens module 3 is stabilized on the sensor module 2, the shape of the leg portion 35 is not particularly limited, but preferably, it is formed in a frame shape surrounding the lens 32 as in the illustrated example. If the leg portion 35 has a frame shape, the space between the wafer piece 21 of the sensor module 2 and the substrate piece 31 of the lens module 3 can be isolated from the outside. It is possible to prevent foreign matters such as the foreign matter from entering and adhering to the solid-state imaging device 22 or the lens 32. Further, in this case, for example, if the leg portion 35 is opaque to visible light, unnecessary light incident on the solid-state imaging device 22 from between the wafer piece 21 and the substrate piece 31 may be blocked by the leg portion 35. it can.

  The imaging unit 1 configured as described above is typically reflow-mounted on a circuit board of a mobile terminal. That is, the circuit board is preliminarily printed with paste-like solder at a position where the imaging unit 1 is mounted, and the imaging unit 1 is placed on the circuit board, and the circuit board including the imaging unit 1 is irradiated with infrared rays. The imaging unit 1 is mounted on the circuit board by performing a heat treatment such as blowing hot air, thereby melting the solder.

  The imaging unit 1 described above has one lens module 3 stacked on the sensor module 2, but a plurality of lens modules 3 may be stacked on the sensor module 2. In this case, the upper lens module 3 laminated on the lens module 3 is laminated by bonding its leg portion 35 to the substrate piece 31 of the lower lens module 3, and the leg portion 35 of the upper lens module 3 is laminated. Is set so that the lens 32 does not contact the lower lens module 3.

  In the lens module 3, the leg portion 35 formed integrally with the substrate piece 31 is described as being joined to the sensor module 2 or another lens module 3 and stacked thereon. Instead of 35, the substrate piece 31 may be laminated via a separate spacer.

  2 and 3 show an example of a lens array.

  The lens array 5 shown in FIGS. 2 and 3 includes a substrate 30 formed of an inorganic material and a plurality of lenses 32 formed of a resin material. The lens module 3 described above is obtained by cutting the substrate 30 and dividing the lens array 5 so as to include the lenses 32 individually. In other words, the lens array 5 is an assembly of the lens modules 3 described above.

  The substrate 30 has a wafer shape (circular shape), and has a plurality of through holes 34 penetrating in the thickness direction. The through holes 34 are arranged in a matrix in the illustrated example. Typically, the substrate 30 has a diameter of 6 inches, 8 inches, or 12 inches, and thousands of through holes 34 are arranged therein. The substrate 30 is not limited to a wafer shape, and may be a rectangular shape, for example. Further, the arrangement of the through holes 34 is not limited to a matrix, and may be, for example, a radial shape, a concentric annular shape, another two-dimensional arrangement, or a one-dimensional arrangement. As the inorganic material forming the substrate 30, a semiconductor such as silicon, ceramics such as glass, metal, or the like can be used.

  As will be described in detail later, the lens 32 is formed by molding a resin material disposed in the through hole 34 into a predetermined shape and filling the through hole 34. The lens 32 formed in this way can be formed entirely of a homogeneous material and has excellent optical performance. That is, a boundary between materials having different optical characteristics such as refractive index is not formed on the optical axis of the lens 32, and it is possible to prevent inconveniences in optical performance such as reflection at the boundary, resulting in flare and ghost. be able to.

  The inner peripheral surface of the through hole 34 is surface-treated with a coupling agent that improves the adhesion between the inorganic material and the resin material (organic material). Thereby, the adhesiveness with the resin material on the inner peripheral surface of the through hole 34 is improved, and the bonding strength between the lens 32 and the substrate 30 is increased.

  Coupling agents include hydrolyzable groups that react with inorganic materials (for example, alkoxy groups, acetoxy groups, chloro atoms, etc.) and functional groups that react with organic materials (for example, vinyl groups, epoxy groups, amino acids). Although it will not specifically limit if it has a group etc., A silane coupling agent, a titanate coupling agent, an aluminate coupling agent, etc. can be used. When the substrate 30 is made of silicon or glass, the silane coupling agent shows better strength, and when the substrate 30 is made of metal, the titanate coupling agent shows better strength. It is preferable to select a coupling agent as appropriate according to the inorganic material forming 30.

  The surface treatment of the inner peripheral surface of the through-hole 34 with the coupling agent may be performed, for example, by immersing the entire substrate 30 in the coupling agent, or for each through-hole 34 with a coupling agent on the inner peripheral surface thereof. You may make it spray or apply | coat. From the viewpoint of improving the bonding strength between the lens 32 and the substrate 30, the thinner the coating of the coupling agent, the better.

  The lens 32 provided by filling the through hole 34 is in close contact with the inner peripheral surface of the through hole 34. Therefore, fine irregularities may be formed on the inner peripheral surface of the through hole 34, in other words, the inner peripheral surface of the through hole 34 may be a rough surface, and surface treatment with a coupling agent may be performed there. The resin material forming the lens 32 enters into the fine irregularities on the inner peripheral surface of the through hole 34, thereby further increasing the bonding strength between the lens 32 and the substrate 30. Furthermore, by making the inner peripheral surface of the through-hole 34 rough, reflection at the boundary surface between the lens 32 and the substrate 30 can be prevented, and generation of ghosts and flares can be prevented.

  When the inner peripheral surface of the through hole 34 is a rough surface, the surface roughness is preferably 4 μm or more and 25 μm or less in terms of 10-point average roughness (Rz). If it is only for preventing reflection, it may be 1 μm or more. However, by setting the above surface roughness range, the lens 32 and the substrate 30 are brought into close contact with the outer peripheral surface of the lens 32 and the inner peripheral surface of the through hole 34. The joint strength can be increased. Examples of the method for making the inner peripheral surface of the through hole 34 rough include blasting, etching, high-temperature oxidation, polishing, and laser processing.

  In the illustrated example, both end portions of the lens 32 in the optical axis direction protrude from the through holes 34, and extended portions 36 that overlap the peripheral portions of the through holes 34 on the surface of the substrate 30 are formed at these end portions. Each is provided. By sandwiching the substrate 30 between the pair of extending portions 36, the bonding strength between the lens 32 and the substrate 30 can be further increased. Even when the extending portion 36 is provided only at one end of both end portions in the optical axis direction of the lens 32, the lens 32 and the substrate 30 are brought into close contact with each other due to the close contact between the extending portion 36 and the surface of the substrate 30. Bond strength is obtained.

  In the example shown in the figure, the extending portion 36 is formed in a substantially circular shape in plan view, extending from the end of the lens 32 protruding from the through hole 34 over the entire circumference, but is not limited thereto. The extending portion 36 may overlap with a part of the peripheral portion of the through hole 34, and may be, for example, one or a plurality of small pieces extending radially from the end portion of the lens 32. In any case, when d is the maximum value of the distance from the optical axis of the lens 32 to the edge of the extending portion 36 and r is the opening radius of the through-hole 34, the extension is achieved by satisfying d> r. The existing portion 36 overlaps the peripheral portion of the through hole 34 on the surface of the substrate 30.

  A plurality of leg portions 35 project from one surface of the substrate 30 (the lower surface in the drawing). The leg portions 35 are arranged in a matrix in the same arrangement as the through holes 34. The leg portion 35 is formed in a frame shape and surrounds the lens 32 filling the through hole 34.

  As described in the imaging unit 1, the leg portion 35 protrudes from the surface of the substrate 30 higher than the surface of the lens 32 exposed on the surface side of the substrate 30 on which the leg portion 35 is provided. That is, with respect to the height h of the lens 32 from the surface of the substrate 30, the height H of the leg portion 35 from the surface of the substrate 30 is H> h.

  4A to 4H each show a modification of the lens array in FIG.

  In the lens array 5 of the modification shown in FIG. 4A, both end portions of the lens 32 protrude from the through holes 34, and extending portions 36 are formed at both end portions. One lens surface 33 of the lens 32 is a concave spherical surface, and the other lens surface 33 is a convex spherical surface.

  In the modified lens array 5 shown in FIG. 4B, both end portions of the lens 32 protrude from the through holes 34, and extending portions 36 are formed at both end portions. Both lens surfaces 33 of the lens 32 are concave spherical surfaces.

  In the lens array 5 of the modified example shown in FIG. 4C, both end portions of the lens 32 protrude from the through holes 34, and extending portions 36 are formed at both end portions. One lens surface 33 of the lens 32 is an aspherical surface, and the other lens surface 33 is a convex spherical surface.

  In the lens array 5 of the modified example shown in FIG. 4D, both end portions of the lens 32 protrude from the through holes 34, and extending portions 36 are formed at both end portions. Both lens surfaces 33 of the lens 32 are aspherical surfaces.

  In the lens array 5 of the modified example shown in FIG. 4E, both end portions of the lens 32 protrude from the through holes 34, and extending portions 36 are formed at both end portions. One lens surface 33 of the lens 32 is an aspherical surface, and its central portion enters the through hole 34. The other lens surface 33 of the lens 32 is a convex spherical surface.

  In the lens array 5 of the modification shown in FIG. 4F, one end of the lens 32 is accommodated in the through hole 34, and only the other end projects from the through hole 34, and the end projects from the through hole 34. The extending part 36 is formed only in the part. One lens surface 33 of the lens 32 is a concave spherical surface, and the other lens surface 33 is a convex spherical surface.

  In the modified lens array 5 shown in FIG. 4G, one end of the lens 32 is accommodated in the through hole 34, and only the other end projects from the through hole 34, and the end projects from the through hole 34. The extending part 36 is formed only in the part. One lens surface 33 of the lens 32 is a concave spherical surface, and the other lens surface 33 is an aspherical surface.

  In the lens array 5 of the modified example shown in FIG. 4H, both end portions of the lens 32 are accommodated in the through hole 34, that is, the entire lens 32 is accommodated in the through hole 34. The extending portion 36 is not provided. Both lens surfaces 33 of the lens 32 are concave spherical surfaces.

  The combination of the shapes of the lens surfaces 33 formed at both ends of the lens 32 in the optical axis direction is not limited to those shown in FIGS. 4A to 4H, and a convex spherical surface or a concave spherical surface is used depending on the application. Various combinations of aspherical surfaces, or aspherical surfaces can be employed.

  A lens in which a part of the lens surface 33 of the lens 32 enters the through hole 34 as shown in FIG. 4E by forming the through hole 34 in the substrate 30 and filling the through hole 34 to provide the lens 32. As shown in FIGS. 4F, 4G, and 4H, one or both ends of the lens 32 and the lens surface 33 formed at the end are accommodated in the through hole 34. This also increases the degree of freedom in lens design. For example, depending on the lens design, the lens surface 33 may have an aspheric shape that can contact the substrate. Here, if the substrate 30 does not have the through hole 34 and it is intended to maintain such an aspherical shape as designed, the periphery of the portion of the lens surface 33 that can come into contact with the substrate 30 is made thicker. Although it is conceivable to avoid contact with the lens surface 33, the thickness of the entire lens increases and the lens 32 becomes larger. On the other hand, if it is going to avoid the enlargement of the lens 32, such an aspherical shape cannot be taken, and the freedom degree of lens design is restrict | limited. On the other hand, as described above, if the substrate 30 has the through hole 34, the lens surface 33 can be embedded in the through hole 34, and the lens design is not limited to the design in which the lens surface 33 does not contact the substrate 30. The degree of freedom is increased, and it is not necessary to make the lens 32 unnecessarily thick, and the lens 32 can be reduced in size (reduced in height).

  Hereinafter, an example of the manufacturing method of the lens array of FIG. 2 will be described.

  5A to 5D show an example of a method for manufacturing a substrate included in the lens array of FIG.

  In the example shown in FIGS. 5A to 5D, for example, the substrate material 40 formed of an inorganic material such as silicon, ceramics such as glass, metal, or the like is subjected to blasting, and a plurality of through holes 34 and a plurality of legs 35 are formed. The substrate 30 is obtained by forming. The substrate material 40 has the same outer shape as the substrate 30 and has the same thickness.

  As shown in FIG. 5A, a blast mask 41 that covers a portion where the leg portion 35 is formed is attached to one surface of the substrate material 40.

  As shown in FIG. 5B, blasting is performed from the surface side of the substrate material 40 to which the mask 41 is attached to a depth H (corresponding to the height of the leg portion 35), and the substrate material not covered with the mask 41 40 regions are removed. Thereby, the leg part 35 is formed.

  As shown in FIG. 5C, a blast mask 42 that exposes a portion where the through hole 34 is formed is attached to the other surface of the substrate material 40.

  As shown in FIG. 5D, blasting is performed from the surface side of the substrate material 40 to which the mask 42 is attached, and the region of the substrate material 40 not covered with the mask 42 is removed. Thereby, the through hole 34 is formed. Blasting makes it easy to control the surface roughness of the treated surface. If the through holes 34 are formed by blasting, the inner peripheral surface can be made rough. Therefore, the inner peripheral surface of the through hole 34 can be made rough at the same time as the formation of the through hole 34.

  Then, for each through hole 34, a coupling agent is applied to the inner peripheral surface of the through hole 34, or sprayed and dried to form a coating film of the coupling agent on the inner peripheral surface of each through hole 34. As described above, the entire substrate 30 on which the through holes 34 are formed may be dipped in a coupling agent to form a coating film of the coupling agent on the inner peripheral surface of each through hole 34.

  In the above example, a blast mask is provided on the substrate material 40, and the through holes 34 and the leg portions 35 are formed by blasting the substrate material 40. Similarly, an etching mask is provided and etching is performed thereon. Through holes 34 and leg portions 35 can also be formed. Further, the inner peripheral surface of the through hole 34 can also be made rough by etching.

  In the case where the through holes 34 and the legs 35 are formed by etching, silicon is preferable as a material for forming the substrate material 40, that is, a material for forming the substrate 30. According to this, anisotropic etching can be performed using, for example, an alkaline aqueous solution such as potassium hydroxide, sodium hydroxide, or hydrazine as an etching solution. In anisotropic etching, the etching does not proceed with respect to a specific crystal orientation. For example, in a potassium hydroxide aqueous solution, the etching hardly proceeds on the surface having the crystal orientation (111). Therefore, if the substrate material 40 has a crystal orientation of (110) as the surface, the through holes 34 and the leg portions 35 having side surfaces substantially perpendicular to the surface of the substrate material 40 can be formed. Further, since silicon is opaque to visible light, the legs 35 formed integrally with the substrate 30 are also opaque to visible light. As described in the above-described imaging unit 1, the wafer piece 21 and the substrate Unnecessary light incident on the solid-state imaging device 22 from between the pieces 31 can be blocked by the legs 35.

  FIG. 6 shows an example of a mold for forming the lenses 32 of the lens array 5 of FIG.

  A mold 50 shown in FIG. 6 compresses a resin material and molds the lens 32, and includes an upper mold 51 and a lower mold 52.

  On the facing surface of the upper mold 51 facing the lower mold 52, lens molding surfaces 53 having a shape obtained by inverting one lens surface 33 of the lens 32 are arranged in the same arrangement as the arrangement of the lenses 32 in the lens array 5. .

  On the facing surface of the lower mold 52 facing the upper mold 51, lens molding surfaces 54 having a shape obtained by inverting the other lens surface 33 of the lens 32 are arranged in the same arrangement as the arrangement of the lenses 32 in the lens array 5. . In addition, on the opposing surface of the lower mold 52, accommodation portions 55 that accommodate the leg portions 35 of the substrate 30 are formed.

  The upper mold 51 and the lower mold 52 sandwich the substrate 30 therebetween. The lens molding surface 53 of the upper mold 51 and the lens molding surface 54 of the lower mold 52, and the inner peripheral surface of the through hole 34 of the substrate 30 positioned between the lens molding surfaces 53, 54, A cavity C for molding the lens 32 is formed.

  The upper mold 51 is formed with an annular recess 56 positioned on the periphery of the through hole 34 on the surface side of the substrate 30 in contact with the upper mold 51. The lower mold 52 is formed with an annular recess 57 extending below the peripheral portion of the through hole 34 on the surface side of the substrate 30 in contact with the lower mold 52. The recesses 56 and 57 both communicate with the cavity C.

  As a resin material for forming the lens 32, for example, an energy curable resin composition can be suitably used. The energy curable resin composition may be either a resin composition that is cured by heat or a resin composition that is cured by irradiation with active energy rays (for example, ultraviolet rays or electron beam irradiation).

  The resin composition forming the lens 32 preferably has appropriate fluidity before curing from the viewpoint of moldability, such as mold shape transfer suitability. Specifically, it is liquid at room temperature and has a viscosity of about 1000 to 50000 mPa · s.

  Moreover, it is preferable that the resin composition which forms the lens 32 has a heat resistance that does not cause thermal deformation even after the reflow process after curing. From this viewpoint, 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 composition, it is necessary to constrain the mobility at the molecular level, and as effective means, (1) means for increasing the crosslinking density per unit volume, (2) Means utilizing a resin having a rigid ring structure (for example, an alicyclic structure such as cyclohexane, norbornane, tetracyclododecane, an aromatic ring structure such as benzene and naphthalene, a cardo structure such as 9,9′-biphenylfluorene, Resins having a spiro structure such as spirobiindane, specifically, for example, JP-A-9-137043, JP-A-10-67970, JP-A-2003-55316, JP-A-2007-334018, JP-A-2007-238883 (3) means for uniformly dispersing a high Tg substance such as inorganic fine particles (for example, JP-A-5-20 027, 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.

  The resin composition forming the lens 32 is preferably a resin composition having a small volume shrinkage due to the curing reaction from the viewpoint of shape transfer accuracy. The curing shrinkage rate of the resin composition is preferably 10% or less, more preferably 5% or less, and particularly preferably 3% or less. Examples of the resin composition having a low curing shrinkage rate include (1) resin compositions containing a high molecular weight curing agent (such as a prepolymer) (for example, JP-A Nos. 2001-19740, 2004-302293, and 2007-). 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, as described in Japanese Patent No. 211247. The value calculated by the number average molecular weight of the curing agent / the number of curing reactive groups is preferably in the range of 50 to 10,000, and in the range of 100 to 5,000. More preferably, it is particularly preferably in the range of 200 to 3,000.), (2) Resins containing non-reactive substances (organic / inorganic fine particles, non-reactive resins, etc.) Composition (for example, described in JP-A-6-298883, JP-A-2001-247793, JP-A-2006-225434, etc.), (3) a resin composition containing a low shrinkage crosslinking reactive group (for example, ring-opening polymerization) Sex groups (for example, epoxy groups (for example, described in JP-A No. 2004-210932), oxetanyl groups (for example, described in JP-A No. 8-134405), episulfide groups (for example, JP-A No. 2002-105110) Etc.), cyclic carbonate groups (e.g. described in JP-A-7-62065 etc.), etc., ene / thiol curing groups (e.g. described in JP-A 2003-20334 etc.), hydrosilylation curing groups (e.g. (For example, described in JP-A-2005-15666), etc.), (4) rigid skeleton resins (fluorene, adamantane, isophorone, etc.) (5) Resin composition containing an interpenetrating network structure (so-called IPN structure) containing two types of monomers having different polymerizable groups (for example, described in JP-A-9-137043) For example, described in JP-A-2006-131868), (6) Resin composition containing an expansible substance (for example, described in JP-A-2004-2719, JP-A-2008-238417, etc.), etc. 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 resin composition containing a prepolymer containing a ring-opening polymerizable group and fine particles).

  Further, the resin composition forming the lens 32 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.

  Further, in the resin composition forming the lens 32, 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-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 composition, for example, a dispersant containing a functional group having reactivity with a resin monomer that forms a matrix (for example, described in Examples of JP 2007-238884 A), hydrophobic Block copolymer composed of a functional segment and a hydrophilic segment (for example, described in JP-A-2007-2111164), or having a functional group capable of forming an arbitrary chemical bond with inorganic fine particles at the polymer terminal or side chain It is desirable to disperse the fine particles by appropriately using a resin (for example, described in JP 2007-238929 A, JP 2007-238930 A, etc.).

  In addition, the resin composition for forming the lens 32 includes a silane coupling agent, a titanate coupling agent, and an aluminate cup that improve adhesion to an inorganic material in order to improve the bonding strength between the lens 32 and the substrate 30. Said coupling agent, such as a ring agent, may be mix | blended suitably.

  In addition, the resin composition forming the lens 32 is appropriately mixed 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 mix | blended with the resin composition which forms the lens 32 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 these curing reaction accelerators to be added varies depending on the type of catalyst and initiator, or the difference in the curing reactive site, and cannot be specified unconditionally, but in general, the total solid content of the curing reactive resin composition About 0.1-15 mass% is preferable with respect to a minute, and about 0.5-5 mass% is more preferable.

  The resin composition forming the lens 32 can be produced 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 composition can be produced by dissolving each component. The solvent that can be used in the curable resin composition is not particularly limited as long as the composition is uniformly dissolved or dispersed without precipitation, and 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 alcohol, butanol, ethylene glycol, etc.), aromatic hydrocarbons (eg, toluene, xylene, etc.), water and the like. When the curable composition contains a solvent, it is preferable to perform a mold shape transfer operation after drying the solvent.

  When the energy curable resin composition is used as the resin material for forming the lens 32, the materials of the upper mold 51 and the lower mold 52 are appropriately selected according to the resin composition. That is, when a thermosetting resin composition is used as the resin composition, a metal material having excellent thermal conductivity, such as nickel, or a material that transmits infrared rays, such as glass, is used as the mold material. In addition, when an ultraviolet curable material is used as the resin material, the mold material is, for example, a material that transmits ultraviolet rays such as glass, and when the resin material is an electron beam curable material. The material of the mold is a material that transmits the electron beam.

  7A to 7C show an example of a method for manufacturing the lens array of FIG.

  As shown in FIG. 7A, the substrate 30 is set on the lower mold 52. The leg portion 35 of the substrate 30 is accommodated in the accommodating portion 55 of the lower mold 52, and the through hole 34 of the substrate 30 is disposed on the lens molding surface 54 of the lower mold 52. Then, the resin material M for forming the lens 32 is supplied to the concave portion formed by the inner peripheral surface of the through hole 34 of the substrate 30 and the lens molding surface 54 of the lower mold 52.

  As shown in FIG. 7B, the upper mold 51 is lowered. As the upper mold 51 is lowered, the resin material M is pressurized between the lens molding surface 53 of the upper mold 51 and the lens molding surface 54 of the lower mold 52 and deformed following the lens molding surfaces 53 and 54. At the same time, it is in close contact with the inner peripheral surface of the through hole 34.

  As shown in FIG. 7C, the cavity C is filled with the resin material M in a state where the upper mold 51 is lowered and the mold 50 is closed. Further, the recess 57 provided in the lower mold 52 and communicating with the cavity C is also filled with the resin material M. The surplus resin material M enters the recess 56 provided in the upper mold 51 and communicating with the cavity C. Some variation occurs in the supply amount of the resin material M, but this variation is absorbed by the concave portion 56 of the upper mold 51.

  In this state, the resin material M is cured by appropriately applying energy for curing, and the lens 32 is formed. The resin material M that has entered the recesses 56 and 57 is cured to form the extended portion 36 of the lens 32.

  FIG. 8 shows a modification of the manufacturing method of the lens array shown in FIGS. 7A to 7C.

  As shown in FIG. 8, when the resin material M contracts during curing, the upper mold 51 is lowered to a position where a predetermined gap g is left between the resin material M and the lower mold 52. At this time, the resin material M is in contact with the entire lens molding surface 53 of the upper mold 51 and the lens molding surface 54 of the lower mold 52. In this state, curing of the resin material M is started. The resin material M contracts as the curing progresses, but the upper mold 51 is made to follow the curing contraction of the resin material M by leaving a gap g between the upper mold 51 and the lower mold 52. Can be lowered. Therefore, it is possible to maintain the close contact between the resin material M and the lens molding surface 53 of the upper mold 51 and continue to apply pressure to the resin material M. Thereby, the lens 32 in which the shapes of the lens molding surface 53 of the upper mold 51 and the lens molding surface 54 of the lower mold 52 are accurately transferred can be obtained. The lowering of the upper die 51 following the curing shrinkage of the resin material M can be performed by the weight of the upper die 51, for example.

  The lens array 5 manufactured as described above is cut into a plurality of lens modules 3 each including a lens 32 by cutting the substrate 30 with a cutter or the like. The separated lens module 3 constitutes the imaging unit 1 in combination with the sensor module 2 as described above.

  9A and 9B show an example of a method for manufacturing the imaging unit of FIG.

  In the example shown in FIGS. 9A and 9B, the lens array 5 is separated into lens modules 3, and the lens modules 3 are stacked on the sensor module 2 to manufacture the imaging unit 1. As shown in FIG. 9A, the substrate 30 of the lens array 5 is cut along the cutting lines L so as to individually include the lenses 32 and the leg portions 35 and separated into the lens modules 3. Then, as shown in FIG. 9B, the individual lens modules 3 are stacked on the sensor module 2 via the leg portions 35 included therein to obtain the imaging unit 1.

  Thus, in each lens module 3, since the leg portion 35 is integrally formed on the substrate piece 31, no separate spacer is required. Therefore, the step of stacking the lens module 3 on the sensor module 2 is performed. Simplified. Thereby, the productivity of the imaging unit 1 can be improved.

  10A to 10C show a modification of the method for manufacturing the imaging unit shown in FIGS. 9A and 9B.

  In the example shown in FIGS. 10A to 10C, two lens modules 3 are stacked on the sensor module 2. As shown in FIG. 10A, one lens array 5 is stacked on another lens array 5 via a plurality of legs 35 included therein, thereby forming a lens array stack 6. Then, as shown in FIG. 10B, the stacked body 6 is formed along the cutting lines L so as to individually include a group of a plurality of lenses 32 aligned in the stacking direction and a group of a plurality of leg portions 35 aligned in the stacking direction. The substrates 30 of the two lens arrays 5 included are cut together and separated into a lens module laminate 7 in which two lens modules 3 are laminated. Then, as illustrated in FIG. 10C, the individual lens module stacked bodies 7 are stacked on the sensor module 2 via the leg portions 35 of the lowermost lens module 3 to obtain the imaging unit 1.

  As described above, when the lens module stack 7 in which the plurality of lens modules 3 are stacked in advance is stacked on the sensor module 2, imaging is performed as compared with the case where the lens modules 3 are sequentially stacked on the sensor module 2. The productivity of the unit 1 can be improved.

  11A and 11B show another example of a method for manufacturing the imaging unit of FIG.

  In the example shown in FIGS. 9A and 9B, the lens array 5 is stacked on the sensor array 4 to configure a plurality of imaging units 1 in a lump, and are separated into individual imaging units 1.

  First, the sensor array 4 will be described. The sensor array 4 includes a wafer 20 formed of a semiconductor material such as silicon. The wafer 20 includes a plurality of lenses arranged in the same arrangement as the lenses 32 in the lens array 5. Are arranged. Typically, the diameter of the wafer 20 is 6 inches, 8 inches, or 12 inches, and thousands of solid-state image sensors 22 are arranged therein.

  As shown in FIG. 11A, the lens array 5 is stacked on the sensor array 4 via a plurality of legs 35 included therein, thereby forming an element array stacked body 8. Then, as shown in FIG. 11B, the sensor array 4 included in the element array stacked body 8 along each cutting line L so as to individually include the solid-state imaging elements 22 and the lenses 32 and the legs 35 arranged in the stacking direction. The wafer 20 and the substrate 30 of the lens array 5 are cut together and separated into the imaging unit 1.

  12A to 12C show a modification of the method for manufacturing the imaging unit shown in FIGS. 11A and 11B.

  In the example shown in FIGS. 12A to 12C, two lens arrays 5 are stacked on the sensor array 4. As shown in FIG. 12A, one lens array 5 is stacked on another lens array 5 via a plurality of legs 35 included therein, thereby forming a lens array stacked body 6. Then, as shown in FIG. 12B, the lens array stacked body 6 is stacked on the sensor array 4 via a plurality of legs 35 included in the lowermost lens array 5 to form an element array stacked body 8. Then, as shown in FIG. 12C, along each cutting line L so as to individually include a group of solid-state imaging elements 22 and a plurality of lenses 32 arranged in the stacking direction, and a group of a plurality of leg portions 35 arranged in the stacking direction. Then, the wafer 20 of the sensor array 4 and the substrate 30 of the two lens arrays 5 included in the element array stack 8 are cut together and separated into the imaging unit 1.

  In this way, one or a plurality of lens arrays 5 are stacked on the sensor array 4, and then the wafer 20 of the sensor array 4 and the substrate 30 of the plurality of lens arrays 5 are cut together to form a plurality of imaging units 1. As a result, the productivity of the imaging unit 1 can be further improved as compared with the case where the separated lens module 3 or the laminated body 7 thereof is assembled to the sensor module 2.

  As described above, the lens array disclosed in the present specification is provided by filling a substrate formed of an inorganic material and a plurality of through holes formed of a resin material and arranged in the substrate. A plurality of lenses, wherein the inner peripheral surface of the through hole is surface-treated with a coupling agent.

  In the lens array disclosed in this specification, the substrate is made of silicon.

  In the lens array disclosed in this specification, the coupling agent is a silane coupling agent.

  In the lens array disclosed in the present specification, the inner peripheral surface of the through hole is a rough surface.

  The lens array disclosed in the present specification is a lens array in which the surface roughness of the inner peripheral surface of the through hole is 4 μm or more and 25 μm or less in terms of 10-point average roughness (Rz).

  The lens array laminate disclosed in this specification includes a plurality of any of the lens arrays described above, and these lens arrays are sequentially laminated.

  The element array stack resistance disclosed in the present specification includes at least one of the lens arrays described above and a sensor array in which a plurality of solid-state imaging elements are arranged on a wafer, and the lens array They are sequentially stacked on the sensor array.

  Further, in the lens module manufacturing method disclosed in the present specification, any one of the lens arrays described above is divided so as to individually include one lens.

  Further, in the manufacturing method of the lens module stacked pair disclosed in the present specification, the lens array stacked body is divided so as to individually include the plurality of lenses arranged in the stacking direction.

  Further, in the manufacturing method of the imaging unit disclosed in this specification, the element array stacked body is divided so as to individually include the solid-state imaging elements and at least one lens arranged in the stacking direction.

DESCRIPTION OF SYMBOLS 1 Imaging unit 2 Sensor module 3 Lens module 4 Sensor array 5 Lens array 6 Lens array laminated body 7 Lens module laminated body 8 Element array laminated body 20 Wafer 21 Wafer piece 22 Solid-state image sensor 30 Substrate 31 Substrate piece 32 Lens 33 Lens surface 34 Through hole 35 Leg 36 Extension 40 Substrate material 41 Mask 42 Mask 50 Mold 51 Upper mold 52 Lower mold 53 Lens molding surface 54 Lens molding surface 55 Housing 56 Recess 57 Recess C Cavity M Resin material

Claims (10)

A lens array comprising: a substrate formed of an inorganic material; and a plurality of lenses formed of a resin material and provided by filling each of the plurality of through holes arranged in the substrate,
A lens array in which an inner peripheral surface of the through hole is surface-treated with a coupling agent. The lens array according to claim 1,
The substrate is a lens array formed of silicon. The lens array according to claim 2, wherein
The lens array, wherein the coupling agent is a silane coupling agent. The lens array according to any one of claims 1 to 3,
A lens array in which an inner peripheral surface of the through hole is a rough surface. The lens array according to claim 4,
The surface roughness of the inner peripheral surface of the through hole is a lens array having a ten-point average roughness (Rz) of 4 μm or more and 25 μm or less.   A lens array laminate comprising a plurality of the lens arrays according to claim 1, wherein the lens arrays are sequentially laminated.   A lens array according to any one of claims 1 to 5, and a sensor array in which a plurality of solid-state imaging elements are arranged on a wafer, wherein the lens array is sequentially stacked on the sensor array. Element array laminate.   A method for manufacturing a lens module, wherein the lens array according to any one of claims 1 to 5 is divided so as to individually include one lens.   A method of manufacturing a lens module laminate, wherein the lens array laminate according to claim 6 is divided so as to individually include a plurality of the lenses arranged in a lamination direction.   The manufacturing method of the imaging unit which divides | segments the element array laminated body of Claim 7 so that the said solid-state image sensor and at least 1 said lens arranged in a lamination direction may be included separately.

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