JP2012185239A - Lens, lens array, and method of manufacturing lens - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens, a lens array and a method of manufacturing the lens in which generation of a ghost due to stray light can be suppressed.SOLUTION: The lens includes: a lens part; a flange part integrally formed by surrounding the outer periphery of the lens part; a reflection suppression layer which is formed on the surface of the flange part with a light-transmitting material and has a rugged surface; and a light-shielding layer formed on the reflection suppression layer with a material having light shielding properties.

Description

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

  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 plurality of lens portions are formed on a substrate portion, there is one shown in Patent Document 1.

  Patent Document 1 describes that a light shielding layer is formed on the surface of the substrate portion of the lens array.

JP 2003-179786 A

  By the way, in the configuration in which the light shielding layer is formed on the lens or the lens array, if the interface between the lens and the light shielding portion is smooth, the light is reflected at the interface inside the lens, stray light is generated, and ghost is generated. It becomes easy to do.

  The present invention has been made in view of the above circumstances, and provides a lens, a lens array, and a lens manufacturing method capable of suppressing the occurrence of a ghost due to stray light.

(1) a lens portion;
Surrounding the outer periphery of the lens part, integrally formed flange part,
A reflection suppressing layer formed of a light transmissive material on the surface of the flange portion and having an uneven surface;
A lens having a light shielding layer formed of a light shielding material on the reflection suppression layer.
(2) A lens manufacturing method comprising: a lens part; and a flange part integrally formed surrounding the outer periphery of the lens part,
A molding die is used to mold a lens array including a plurality of the lens portions and a substrate portion that integrally connects the plurality of lens portions,
Cutting the substrate part and separating the plurality of lens parts individually;
On the surface of the flange portion attached to the separated lens portion, a light-transmitting material is applied to form a reflection suppressing layer having an uneven surface,
A method for manufacturing a lens, wherein a light shielding layer is formed on the reflection suppressing layer using a light shielding material.
(3) A lens array having a plurality of lens portions and a substrate portion integrally connecting the plurality of lens portions,
A reflection suppressing layer formed of a light transmissive material on the surface of the substrate portion and having an uneven surface;
A lens array comprising: a light shielding layer made of a light shielding material on the reflection suppression layer.

  According to the present invention, it is possible to provide a lens, a lens array, and a lens manufacturing method that can suppress the occurrence of a ghost due to stray light.

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 sectional drawing which shows a lens array. It is typical sectional drawing which shows the procedure of the manufacturing method of a lens. It is sectional drawing which shows the lens molded object obtained by the shaping | molding process of FIG.

  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 having a lens portion 6 and a flange portion 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 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 lens is formed by laminating a reflection suppressing layer 8 a and a light shielding layer 8 b on the surface of the flange portion 7 in this order.

  The reflection suppression layer 8a is formed of a light transmissive material. The reflection suppressing layer 8a has an uneven surface on the inner surface located at the boundary with the light shielding layer 8b. As the material of the reflection suppressing layer 8a, a material having a refractive index equivalent to that of the material constituting the lens is used.

  The light shielding layer 8b is laminated on the reflection suppressing layer 8a and is formed of a light shielding material.

  A method for forming the reflection suppressing layer 8a and the light shielding layer 8b will be described later.

  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 divides a lens array in which a plurality of lens portions 6 are arranged one-dimensionally or two-dimensionally so as to include the lens portions 6 individually, thereby forming a reflection suppressing layer 8a and a light-shielding layer 8b. Can be obtained. 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. Below, the lens array used in order to produce the lens module 3 is demonstrated.

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 is formed in a wafer shape of a predetermined size as a whole, and a plurality of lens portions 6 are arranged there. In the illustrated example, the plurality of lens portions 6 are two-dimensionally arranged. The lens array 10 is also referred to as a wafer level lens array. The lens unit 6 and the substrate unit 11 are integrally formed of a translucent material.

  The substrate portion 11 is cut between the adjacent lens portions 6 of the lens array 10, and the substrate portion 11 attached to each cut lens portion 6 becomes the flange portion 7. And the lens of the lens module 3 is obtained by forming the reflection suppression layer 8a and the light shielding layer 8b in the surface of the flange part 7, and a cut surface. A method for manufacturing the lens will be described later.

FIG. 4 shows a configuration in which the reflection suppressing layer 8 a and the light shielding layer 8 b are formed on the surface of the substrate portion 11 without cutting the lens array 10.
The lens array 10 shown in FIG. 4 is formed by laminating a reflection suppressing layer 8a and a light shielding layer 8b in this order on the upper surface of the substrate portion 11. Further, the reflection suppressing layer 8a and the light shielding layer 8b are laminated in this order also on the outer peripheral surface of the lens array 10 (the end surface of the substrate portion 11 on the outer peripheral edge). Although not shown, the reflection suppressing layer 8a and the light shielding layer 8b may be laminated on the lower surface of the substrate portion 11 in this order.

  Next, an example of a method for manufacturing the lens of the lens module 3 will be described. FIG. 5A to FIG. 5C are schematic cross-sectional views showing the procedure of the lens manufacturing method.

  First, based on FIG. 5A, the structure of the shaping | molding die used for manufacture of a lens is demonstrated. The mold includes a pair of upper and lower molds 20 and 30. The mold 20 has a transfer surface 21, and the mold 30 has a transfer surface 31. The transfer surface 21 of the mold 20 shapes the shape of one surface of the lens array 10, and the transfer surface 31 of the mold 30 shapes the shape of the other surface of the lens array 10.

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

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

Next, the procedure of the manufacturing method will be described.
As shown in FIG. 5A, the resin M is supplied between the pair of molds 20 and 30, the resin M is sandwiched between the transfer surface 21 and the transfer surface 31, and the shapes of the transfer surface 21 and the transfer surface 31 are formed in the material M. Transcript. Then, the resin M is cured. After the resin M is cured, the lens molded body including the substrate unit 11 that integrally connects the plurality of lens units 6 is released from the molds 20 and 30. Thus, the lens array 10 can be obtained as shown in FIG. 5B.

  As the material of the resin M, an energy curable resin composition having light transmittance 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. 5C, the substrate portion 7 of the lens array 10 is cut by a dicing blade 40 and separated into individual lens portions 6. A part of the cut substrate portion 11 is attached to the separated lens portion 6. The substrate portion 11 attached to the lens portion 6 becomes the flange portion 7. In this way, a lens including the lens portion 6 and the flange portion 7 integrally formed surrounding the outer periphery of the lens portion 6 can be obtained. The flange portion 7 of the lens has a flat cut surface formed by cutting with the dicing blade 40.

  Thereafter, as shown in FIGS. 6A and 6B, a reflection suppressing layer 8a and a light shielding layer 8b are sequentially formed on the surface of the flange portion 7 of the lens. The reflection suppressing layer 8a and the light shielding layer 8b are formed not only on the surface of the lens flange portion 7 but also on the cut surface of the lens.

  FIG. 6A is a schematic cross-sectional view showing a state in which a reflection suppressing layer 8a is formed on the surface of the flange portion 7 of the lens.

  The reflection suppression layer 8a is formed on the surface of the flange portion 7 by a light transmissive material applied by a coating method described later. Further, the reflection suppressing layer 8 a has an uneven surface for scattering light inside the lens portion 6 and the flange portion 7.

  The uneven surface of the reflection suppressing layer 8a preferably has a surface roughness of 0.1 μm or more, more preferably 0.2 μm or more, and most preferably 0.3 μm or more.

  As an application method for applying the material of the reflection suppressing layer 8a, any one of ink jet printing, dip coating, and spray coating is used.

  In the application using ink jet printing, the drawing pitch and the compatibility of the material of the reflection suppressing layer 8a and the lens material are adjusted, and the material of the reflection suppressing layer 8a is applied so as to obtain a desired uneven pattern.

  In application using spray coating, the nozzle diameter of the spray and the distance between the nozzle and the application surface of the lens are adjusted, and control is performed so as to obtain an uneven pattern with a desired particle size.

As an application method for applying the material of the reflection suppressing layer 8a, spray application is most preferable. The reason is that the uneven surface formed by spray coating can be adjusted in the uneven size by adjusting the nozzle or adjusting the liquid viscosity. There is a certain degree of unevenness in the uneven size on the uneven surface formed by spray coating. In a state where there is no such unevenness (for example, a state where the concavo-convex shape is present at a constant size and a constant pitch), there is a possibility that light strengthened by light interference becomes a ghost.
In addition, in the case of coating by ink jet, the surface tension and viscosity limit the coating conditions and environment in which the concavo-convex shape can be created. On the other hand, in spray coating, it is possible to form a stable concavo-convex shape without being greatly affected by liquid properties.
Furthermore, when spray coating is used, it is possible to form a concavo-convex shape with high concavo-convex followability when the ruggedness of the lens is large or when the lens is applied to the end of the lens unit.

  Alternatively, a material for the antireflection layer 8a may be applied, and the surface of the coating solution may be wrinkled (ethylation) by controlling the curing rate of the coating solution, and the uneven surface may be formed by the wrinkles. As an example, UV curable resin is applied by dip coating or spray coating, the amount of UV irradiation is adjusted so that only the surface layer side of the coating film is cured, the resin is cured, and heating causes fine wrinkles on the surface. Generates unevenness.

  Alternatively, light scattering particles (in this case, the refractive index may not be the same as that of the resin constituting the lens) are mixed into the material of the reflection suppressing layer 8a to be applied, whereby irregularities are formed on the surface layer side of the coating film. Form.

  FIG. 6B is a schematic cross-sectional view showing a state in which the light shielding layer 8b is formed on the reflection suppressing layer 8a of the flange portion 7 of the lens.

  The light shielding layer 8b is formed by applying an organic material having a light shielding property. At this time, the material application method of the light shielding layer 8b may be the same as the material application method of the reflection suppression layer 8a described above.

  The light shielding layer 8b may be formed by vapor-depositing a light shielding material made of an organic material or an inorganic material on the reflection suppressing layer 8a.

In the lens thus obtained, light can be prevented from entering the flange portion 7 from the outside by the light shielding layer 8b, and the occurrence of ghosts due to stray light can be suppressed by scattering the light inside the lens by the reflection suppressing layer 8a. .
In addition, in each lens when a plurality of lens portions are stacked or in the lens on the sensor side, light from the outside of the lens is not only shielded but also scattered, and ghosting due to regular reflection on the outer surface of the lens can be suppressed.

  In order to impart light scattering properties to the surface of the substrate part 11, a method of forming a rough surface on the surface of the substrate part 11 by transferring a mold is also conceivable, but in this case, between the surface of the base part and the transfer surface of the mold. The releasability is deteriorated, linear expansion occurs due to defective release, and defects such as cracks and residual internal stress occur in the lens molded body. In the present invention, since the reflection suppressing layer 8a is formed after the lens array 10 is molded, the lens array 10 can be molded with the smoothness of the surface of the substrate portion 11 and the mold release property. Decreasing can be avoided.

This specification discloses the following contents.
(1) a lens portion;
Surrounding the outer periphery of the lens part, integrally formed flange part,
A reflection suppressing layer formed of a light transmissive material on the surface of the flange portion and having an uneven surface;
A lens having a light shielding layer formed of a light shielding material on the reflection suppression layer.
(2) The lens according to (1),
The lens in which the flange portion has a surface formed by cutting, and the reflection suppressing layer and the light shielding layer are formed on the surface.
(3) A lens manufacturing method comprising: a lens part; and a flange part integrally surrounding the outer periphery of the lens part,
A molding die is used to mold a lens array including a plurality of the lens portions and a substrate portion that integrally connects the plurality of lens portions,
Cutting the substrate part and separating the plurality of lens parts individually;
On the surface of the flange portion attached to the separated lens portion, a light-transmitting material is applied to form a reflection suppressing layer having an uneven surface,
A method for manufacturing a lens, wherein a light shielding layer is formed on the reflection suppressing layer using a light shielding material.
(4) It is a manufacturing method of a lens given in (3),
The method for producing a lens, wherein the reflection suppressing layer and the light shielding layer are also formed on a cut surface of a flange portion attached to the separated lens portion.
(5) The method for producing a lens according to (3) or (4),
The method for applying the antireflection layer is a lens manufacturing method in which any one of ink jet printing, dip coating, and spray coating is used.
(6) The method for manufacturing a lens according to (5),
The said light shielding layer is a manufacturing method of the lens formed using the same coating system as the said reflection suppression layer.
(7) The method for manufacturing a lens according to (5),
The said light shielding layer is a manufacturing method of the lens formed by vapor deposition.
(8) A lens array having a plurality of lens portions and a substrate portion integrally connecting the plurality of lens portions,
A reflection suppressing layer formed of a light transmissive material on the surface of the substrate portion and having an uneven surface;
A lens array comprising: a light shielding layer made of a light shielding material on the reflection suppression layer.

DESCRIPTION OF SYMBOLS 1 Imaging unit 2 Sensor module 3 Lens module 6 Lens part 7 Flange part 8a Reflection suppression layer 8b Light-shielding layer 10 Lens array 11 Substrate parts 20 and 30 Mold

Claims (8)

The lens part,
Surrounding the outer periphery of the lens part, integrally formed flange part,
A reflection suppressing layer formed of a light transmissive material on the surface of the flange portion and having an uneven surface;
A lens having a light shielding layer formed of a light shielding material on the reflection suppression layer. The lens according to claim 1,
The lens in which the flange portion has a surface formed by cutting, and the reflection suppressing layer and the light shielding layer are formed on the surface. A lens manufacturing method comprising: a lens part; and a flange part integrally formed surrounding the outer periphery of the lens part,
A molding die is used to mold a lens array including a plurality of the lens portions and a substrate portion that integrally connects the plurality of lens portions,
Cutting the substrate part and separating the plurality of lens parts individually;
On the surface of the flange portion attached to the separated lens portion, a light-transmitting material is applied to form a reflection suppressing layer having an uneven surface,
A method for manufacturing a lens, wherein a light shielding layer is formed on the reflection suppressing layer using a light shielding material. A method of manufacturing a lens according to claim 3,
The method for producing a lens, wherein the reflection suppressing layer and the light shielding layer are also formed on a cut surface of a flange portion attached to the separated lens portion. It is a manufacturing method of the lens according to claim 3 or 4,
The method for applying the antireflection layer is a lens manufacturing method in which any one of ink jet printing, dip coating, and spray coating is used. It is a manufacturing method of the lens according to claim 5, Comprising:
The said light shielding layer is a manufacturing method of the lens formed using the same coating system as the said reflection suppression layer. It is a manufacturing method of the lens according to claim 5, Comprising:
The said light shielding layer is a manufacturing method of the lens formed by vapor deposition. A lens array having a plurality of lens portions and a substrate portion integrally connecting the plurality of lens portions;
A reflection suppressing layer formed of a light transmissive material on the surface of the substrate portion and having an uneven surface;
A lens array comprising: a light shielding layer made of a light shielding material on the reflection suppression layer.

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