JP2012185238A - Method for manufacturing lens array, lens array, and lens module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a lens array in which the lens array can be molded in a predetermined shape with high reproducibility.SOLUTION: Disclosed is a method for manufacturing the lens array having a plurality of lens parts, and a substrate part formed integrally with the plurality of the lens parts. In this method, a molding die is used which is equipped with a pair of dies, each of which is formed in a shape following the outer peripheral shape of the lens array on a transfer surface including a lens transfer part having the shape obtained by inverting the shapes of the lens parts and has bank-like projection parts, resin as a material of the lens array is supplied to an area having the shape following the outer peripheral shape of the lens array and partitioned by the bank-like projection parts on the transfer surface of each of a pair of the dies, the resin is sandwiched by a pair of the dies, the resin is deformed according to the shape of the transfer surface while flowing the resin from gaps between the projection parts of the transfer surface of each of a pair of the dies, and the resin sandwiched by a pair of the dies is cured to form the resin existing between the projection parts into thin wall parts, thereby making the lens array made of the cured resin released from a pair of the dies after curing of the resin while using the thin wall parts as starting points.

Description

  The present invention relates to a lens array manufacturing method, a lens array, and a lens module.

  In recent years, portable terminals 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, a lens for forming a subject image on the solid-state imaging device, It has.

  In order to reduce the cost of the imaging unit, it is desired to improve the efficiency of the lens manufacturing method so that a large number of lenses mounted on the imaging unit can be manufactured at low cost. Such a lens is obtained by manufacturing a lens array having a configuration in which a plurality of lens portions are integrally formed on a substrate portion, and cutting the substrate portion to separate the plurality of lens portions, respectively. To be implemented.

  As a lens array in which a substrate portion and a plurality of lens portions are integrally formed, there is one shown in Patent Document 1.

  As a process for manufacturing such a lens array, a resin material is supplied to the center of the transfer surface of the mold, the resin material is sandwiched between a pair of upper mold and lower mold, and the resin material is moved from the center of the mold toward the periphery. spread. Thus, the resin material is deformed into a substantially disk shape and then cured. Then, after the resin material is cured, the molded lens array is released from the upper mold and the lower mold.

JP 2010-266666 A

  By the way, in the molding of the resin material by the pair of upper mold and lower mold as described above, the shape of the outer periphery of the lens array obtained by molding is not stable, so the reproducibility when molding a lens array of a predetermined shape is low. It was.

  The present invention provides a method of manufacturing a lens array that can form a lens array having a predetermined shape with high reproducibility.

The present invention is a method of manufacturing a lens array having a plurality of lens portions and a substrate portion formed integrally with the plurality of lens portions,
A mold having a transfer surface including a lens transfer portion having a shape obtained by inverting the shape of the lens portion, and provided with a shape matching the outer peripheral shape of the lens array on the transfer surface and having a bank-like protrusion formed thereon Using a mold with a pair,
Supplying the resin that is the material of the lens array to the transfer surface of each of the pair of molds, in a region that is provided in a shape that matches the outer peripheral shape of the lens array and that is partitioned by a bank-shaped protrusion.
The resin is sandwiched between the pair of molds,
The resin is deformed following the shape of the transfer surface while the resin flows out from the gap between the protrusions of the transfer surfaces of the pair of molds,
The resin sandwiched between the pair of molds is cured, and the resin existing between the protrusions is a thin-walled part,
After the resin is cured, the lens array made of the cured resin is released from the pair of molds starting from the thin portion.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the lens array which can shape | mold the lens array of a predetermined shape with high reproducibility can be provided.

It is sectional drawing which shows an example of the imaging unit for demonstrating embodiment of this invention. It is a figure which shows an example of the lens array for describing embodiment of this invention. FIG. 3 is a cross-sectional view of the lens array of FIG. 2 taken along the line III-III. It is the figure which planarly viewed the transfer surface of the mold. It is typical sectional drawing which shows a shaping | molding die and the shaping | molding process using a shaping | molding die. It is typical sectional drawing which shows the shaping | molding process using the shaping | molding die of FIG. It is typical sectional drawing which shows the process of releasing a molded object from the shaping | molding die of FIG. It is a top view which shows the modification of a structure of a type | mold. It is a top view which shows the modification of a structure of a type | mold.

  An imaging unit 1 shown in FIG. 1 includes a sensor module 2 and a lens module 3.

  The sensor module 2 includes a solid-state imaging device 4 and a sensor substrate unit 5. The sensor substrate unit 5 is formed of a semiconductor material such as silicon. The solid-state imaging device 4 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, and the like on the sensor substrate section 5 to thereby form the sensor substrate section 5. A light receiving region, an insulating film, an electrode, a wiring, and the like are formed thereon.

  The lens module 3 includes a lens unit 6 and a flange unit 7. The lens unit 6 has predetermined lens surfaces 6a and 6b on the front and back. Both lens surfaces 6a and 6b are convex spherical surfaces in the illustrated example, but various combinations of convex spherical surfaces, concave spherical surfaces, aspherical surfaces, or flat surfaces are adopted depending on the application. obtain. The flange portion 7 protrudes from the outer periphery of the lens portion 6 in a bowl shape and surrounds the outer periphery of the lens portion 6. The lens part 6 and the flange part 7 are integrally formed of a translucent material.

  The lens module 3 is laminated on the sensor module 2 via the spacer 9 between the flange portion 7 and the sensor substrate portion 5 and assembled to the sensor module 2. The spacer 9 is provided between the sensor substrate portion 5 of the sensor module 2 and the flange portion 7 of the lens module 3 so that the lens portion 6 of the lens module 3 forms an image on the light receiving surface of the solid-state imaging device 4 of the sensor module 2. The thickness is set at a predetermined distance. The spacer 9 and both the modules 2 and 3 are joined using, for example, an adhesive.

  The shape of the spacer 9 is not particularly limited as long as a predetermined distance can be placed between the sensor substrate portion 5 of the sensor module 2 and the flange portion 7 of the lens module 3, but surrounds the solid-state imaging device 4. Thus, it is preferable that the frame-shaped member is used to isolate the modules 2 and 3 from the outside. According to this, it is possible to prevent foreign matters such as dust from entering between the modules 2 and 3 and adhering to the light receiving surface of the solid-state imaging device 4. Furthermore, if the spacer 9 is formed of a light-shielding material, unnecessary light that enters the solid-state imaging device 4 from between the modules 2 and 3 can be blocked.

  In the illustrated example, one lens module 3 is assembled to the sensor module 2, but a plurality of lens modules 3 may be assembled. In this case, the plurality of lens modules 3 are sequentially stacked via a spacer equivalent to the spacer 9 and assembled to the sensor module 2. Further, the lens surfaces 6 a and 6 b of these lens portions 6 may be different for each lens module 3.

  The imaging unit 1 configured as described above is reflow-mounted on a circuit board such as a portable terminal. Paste solder is printed in advance on the circuit board at a position where the imaging unit 1 is mounted, and the imaging unit 1 is placed there. The circuit board including the imaging unit 1 is subjected to heat treatment such as infrared irradiation or hot air blowing. As a result, the solder is melted and the imaging unit 1 is mounted on the circuit board.

  The lens module 3 described above is obtained by dividing a lens array in which a plurality of lens units 6 are arranged one-dimensionally or two-dimensionally so as to include the lens units 6 individually. Similarly, the above-described sensor module 2 is obtained by dividing a sensor array in which a plurality of solid-state image sensors are arranged one-dimensionally or two-dimensionally so as to include individual solid-state image sensors. The lens array for obtaining the lens module 3 will be described below.

FIG. 2 is a plan view showing the lens array. FIG. 3 is a cross-sectional view of the lens array in FIG. 2 taken along the line III-III.
The lens array 10 shown in FIGS. 2 and 3 includes a plurality of lens portions 6 and a substrate portion 11 that integrally connects these lens portions 6. The lens array 10 has a wafer shape of a predetermined size as a whole, and is also referred to as a wafer level lens array in which a plurality of lens units 6 are arranged. In the illustrated example, the plurality of lens units 6 are two-dimensional. Is arranged. The lens unit 6 and the substrate unit 11 are integrally formed of a translucent material.

  The lens module 3 (see FIG. 1) described above is obtained by cutting the substrate portion 11 between adjacent lens portions 6 in the lens array 10. The substrate part 11 cut and attached to each lens part 6 becomes the flange part 7 of the lens module 3. It is possible to obtain a lens array laminate in which a plurality of lens arrays in FIG. 3 are stacked and the overlapping lens arrays are bonded together. At this time, the lens portions of the lens array are aligned and overlapped so that the optical axes coincide with the lens portions of the overlapped lens arrays. Then, the lens array laminate obtained in this manner is cut at the substrate portion, and a lens module in which a plurality of lens portions are stacked so that their optical axes coincide can be obtained.

  Next, a method for manufacturing the lens array 10 will be described.

  First, based on FIG.4 and FIG.5, the structure of the shaping | molding die used for a shaping | molding process is demonstrated.

  The mold includes a pair of upper and lower molds 20 and 30. In the mold 20, the transfer surface 21 shapes the shape of one surface of the lens array 10, and the mold 30 shapes the shape of the other surface of the lens array 10. In FIG. 4, the configuration of the mold 20 is shown, but the configuration of the mold 30 is the same, and is omitted from the drawing.

  The mold 20 includes a transfer surface 21. The mold 30 includes a transfer surface 31. The transfer surface 21 has a shape obtained by inverting one surface of the lens array 10, and the transfer surface 31 has a shape obtained by inverting the other surface of the lens array 10.

  A lens molding surface 22 is two-dimensionally arranged on the transfer surface 21 of the mold 20 corresponding to the arrangement of the lens portions 6 of the lens array 10. The lens molding surface 22 is molded into a concave spherical surface corresponding to the lens surface 6a which is a convex spherical surface.

  Further, the transfer surface 21 is provided with a bank-like protrusion 23 provided in a shape matching the outer peripheral shape (here, a perfect circle shape) of the lens array 10. The protrusion 23 partitions a circular area including all the lens transfer portions 22 on the transfer surface 21.

  In addition, although it is preferable that the protrusion part 23 is continuously formed in the shape of a bank with a fixed height, it is not necessary to be completely continuous and a fixed height, and it is partially low, or there is no protrusion partially. It does not matter in shape.

  A lens molding surface 32 is two-dimensionally arranged on the transfer surface 31 of the mold 30 corresponding to the arrangement of the lens portions 6 of the lens array 10. The lens molding surface 32 is molded into a concave spherical surface corresponding to the lens surface 6a which is a convex spherical surface.

  The transfer surface 31 is formed with a bank-like protrusion 33 provided in a shape matching the outer peripheral shape of the lens array 10. The protrusion 33 partitions a circular area including all the lens transfer portions 32 on the transfer surface 31.

  The protrusions 23 and 33 are equal in size and shape. Further, the protrusions 23 and 33 each have a height from the transfer surfaces 21 and 31 of several tens of micrometers to several hundreds of micrometers.

  Next, the procedure of the manufacturing method using the above-described mold will be described.

  First, as shown in FIG. 5, a resin M, which is a lens array material, is supplied onto the transfer surface 31 of the mold 30. At this time, the resin M is supplied in an amount that is greater than or equal to the amount required to mold the lens array. The resin M is controllably supplied using a supply device such as a dispenser (not shown). Further, the resin M is supplied to a substantially central portion of the transfer surface 31.

  As the material of the resin M, an energy curable resin composition is 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).

  As shown in FIG. 6, the resin M is sandwiched between the molds 20 and 30. At this time, when the gap between the transfer surfaces 21 and 31 of the molds 20 and 30 is minimized, a gap is generated between the protrusions 23 and 33 of the transfer surfaces 21 and 31. Then, the sandwiched resin M flows out of the region surrounded by the protrusions 23 and 33 from the gap between the protrusions 23 and 33. Further, the resin M in the region surrounded by the protrusions 23 and 33 is deformed following the shape of the transfer surfaces 21 and 31.

  Thereafter, the resin M sandwiched between the molds 20 and 30 is cured. A thin portion is formed by the resin M present between the protrusions 23 and 33.

  After the resin is cured, the lens array 10 made of the cured resin M is released from the molds 20 and 30 as shown in FIG. At this time, the lens array 10 is released from the thin portion as a starting point. Specifically, since the resin shrinks during curing, the stress due to the shrinkage concentrates on the resin M near the gap between the protrusions 23 and 33. Then, the thin-walled portion of the resin M is broken, and the cured resin M in the region surrounded by the protrusions 23 and 33 is separated from the resin M on the outer peripheral side. Thus, the lens array 10 is formed by the cured resin M in the region surrounded by the protrusions 23 and 33. Therefore, the outer peripheral shape of the released lens array 10 is a shape defined by the protrusions 23 and 33 on the transfer surfaces 21 and 31.

  According to the manufacturing method described above, a lens array having a predetermined shape can be formed with high reproducibility. It is also advantageous in that when the lens array 10 is released from the molds 20 and 30, it is not necessary to perform a step of releasing using another member or a processing method.

  Next, a modified example of the above-described embodiment will be described.

  The shape of the lens array to be molded is not limited to a perfect circular shape. For example, a predetermined shape such as a shape in which an orientation flat (so-called orientation flat) is provided in part or a shape that matches the shape of a holder for holding the lens array when performing alignment of the lens array in a later step. Can be adopted. In the present invention, a lens array having such a shape can be obtained with high reproducibility by molding with a mold having a protrusion. In the conventional method of molding by sandwiching a resin between a pair of molds, it has been impossible to mold a lens array having such a shape with high reproducibility.

  FIG. 8 is a plan view showing a modification of the configuration of the mold. The mold 20 is provided with a protrusion 23 on the transfer surface 21 in a shape matching the outer peripheral shape of the lens array provided with the orientation flat. The protrusion 23 is formed with a flat portion 23 f at a portion corresponding to the orientation flat of the lens array 10. Although not shown, the pair of molds 30 has the same configuration. The method for molding the lens array 10 using the molds 20 and 30 can be the same procedure as described above.

  FIG. 9 is a plan view showing a modification of the configuration of the mold. The mold 20 is provided with a protrusion 23 on the transfer surface 21 in a shape matching the shape of a holder for holding the lens array. The protrusion 23 is formed with a flat portion 23f at a portion corresponding to the alignment surface of the holder. In the example illustrated in FIG. 9, the protrusion 23 has two pairs of flat portions 23 f having planes parallel to each other. Although not shown, the pair of molds 30 has the same configuration. The method for molding the lens array 10 using the molds 20 and 30 can be the same procedure as described above.

This specification discloses the following contents.
(1) A method of manufacturing a lens array having a plurality of lens portions and a substrate portion formed integrally with the plurality of lens portions,
A mold having a transfer surface including a lens transfer portion having a shape obtained by inverting the shape of the lens portion, and provided with a shape matching the outer peripheral shape of the lens array on the transfer surface and having a bank-like protrusion formed thereon Using a mold with a pair,
Supplying the resin that is the material of the lens array to the transfer surface of each of the pair of molds, in a region that is provided in a shape that matches the outer peripheral shape of the lens array and that is partitioned by a bank-shaped protrusion.
The resin is sandwiched between the pair of molds,
The resin is deformed following the shape of the transfer surface while the resin flows out from the gap between the protrusions of the transfer surfaces of the pair of molds,
The resin sandwiched between the pair of molds is cured, and the resin existing between the protrusions is a thin-walled part,
A method of manufacturing a lens array, wherein after the resin is cured, the lens array made of the cured resin is released from the pair of molds starting from the thin portion.
(2) A method of manufacturing the lens array according to (1),
The manufacturing method of the lens array whose outer periphery shape of the said lens array is a perfect circle.
(3) The method for manufacturing the lens array according to (1),
The manufacturing method of the lens array whose outer periphery shape of the said lens array is substantially circular shape including orientation flat.
(4) A method of manufacturing the lens array according to (1),
A manufacturing method of a lens array, wherein an outer peripheral shape of the lens array is a shape matched with a holder for holding the lens array for alignment after mold release.
(5) A lens module obtained by cutting the substrate portion of the lens array manufactured by the method for manufacturing a lens array according to any one of (1) to (4), and dividing the substrate portion into individual lens portions.
(6) A lens array laminate formed by stacking a plurality of the lens arrays manufactured by the method for manufacturing a lens array according to any one of (1) to (4), and bonding the overlapping lens arrays.
(7) A lens module in which the lens array laminate according to (6) is cut at the substrate portion, and the plurality of lens portions are overlapped so that their optical axes coincide.

DESCRIPTION OF SYMBOLS 1 Imaging unit 2 Sensor module 3 Lens module 6 Lens part 10 Lens array 11 Board | substrate part 20 and 30 Mold 21 Transfer surface 22 Lens transfer part 23 and 33 Projection part

Claims (7)

A method of manufacturing a lens array having a plurality of lens portions and a substrate portion formed integrally with the plurality of lens portions,
A mold having a transfer surface including a lens transfer portion having a shape obtained by inverting the shape of the lens portion, and provided with a shape matching the outer peripheral shape of the lens array on the transfer surface and having a bank-like protrusion formed thereon Using a mold with a pair,
Supplying the resin that is the material of the lens array to the transfer surface of each of the pair of molds, in a region that is provided in a shape that matches the outer peripheral shape of the lens array and that is partitioned by a bank-shaped protrusion.
The resin is sandwiched between the pair of molds,
The resin is deformed following the shape of the transfer surface while the resin flows out from the gap between the protrusions of the transfer surfaces of the pair of molds,
The resin sandwiched between the pair of molds is cured, and the resin existing between the protrusions is a thin-walled part,
A method of manufacturing a lens array, wherein after the resin is cured, the lens array made of the cured resin is released from the pair of molds starting from the thin portion. A method of manufacturing a lens array according to claim 1,
The manufacturing method of the lens array whose outer periphery shape of the said lens array is a perfect circle. A method of manufacturing a lens array according to claim 1,
The manufacturing method of the lens array whose outer periphery shape of the said lens array is substantially circular shape including orientation flat. A method of manufacturing a lens array according to claim 1,
A manufacturing method of a lens array, wherein an outer peripheral shape of the lens array is a shape matched with a holder for holding the lens array for alignment after mold release.   5. A lens module obtained by cutting the substrate portion of the lens array manufactured by the method for manufacturing a lens array according to claim 1, and dividing the substrate portion into individual lens portions.   5. A lens array laminate obtained by stacking a plurality of the lens arrays manufactured by the method for manufacturing a lens array according to claim 1, and bonding the overlapping lens arrays together.   7. A lens module, wherein the lens array laminate according to claim 6 is cut at the substrate portion, and the plurality of lens portions are overlapped so that their optical axes coincide.

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