JPWO2011010510A1 - Imaging lens - Google Patents

Abstract

The present invention is an imaging lens in which a lens portion made of plastic and a spacer made of plastic are formed on at least one surface of a glass substrate, and the lens portion relative to the surface area of each surface of the glass substrate is An imaging lens, wherein a total ratio of an area of a portion in contact with the glass substrate and an area of a portion of the spacer in contact with the glass substrate is 50% or less. ADVANTAGE OF THE INVENTION According to this invention, the imaging lens excellent in heat resistance in a manufacturing process and a solder reflow process, the imaging lens group consisting thereof, a camera module, etc. can be provided.

Description

  The present invention relates to an imaging lens. More specifically, the present invention relates to an imaging lens that can be manufactured in a state without thermal deformation or the like even by a manufacturing process including a heating process, or exhibits excellent heat resistance in a solder reflow process.

  Conventionally, an imaging lens unit using an imaging lens group composed of a plurality of imaging lenses, such as an imaging lens unit of a camera, has a spacer part for maintaining a predetermined distance between lenses after molding the lens part. Further, it has been manufactured through a complicated process of fixing each lens by aligning the positions so that the optical axes of the lenses coincide with each other. As a method for simplifying the manufacturing process of an imaging lens unit using such an imaging lens group, an imaging lens unit using an imaging lens in which a member for performing an inter-lens distance and optical axis alignment is formed on the imaging lens, etc. Has been developed (Patent Document 1).

  On the other hand, in recent manufacture of electronic devices, a solder reflow process is often employed as a process for downsizing various electronic components or modules and mounting them on a substrate with high productivity. In the solder reflow process, the electronic components on the substrate are heated at a high temperature of 220 to 270 ° C. to melt and bond the solder. Therefore, durability in the solder reflow process is required for optical components such as lenses, prisms, and transparent covers that are mounted on electronic modules, particularly optical modules such as cameras and lights.

  In recent years, regarding a reflow-resistant imaging lens for a camera module, as shown in Non-Patent Document 1, an imaging lens in which a lens structure is formed of plastic on both surfaces of a glass substrate at a wafer level and a manufacturing method thereof have been proposed. ing. In this imaging lens, a spacer portion for adjusting the interval when the imaging lenses are overlapped is formed.

  However, in this type of conventional imaging lens, when the spacer and the lens portion are made of plastic and formed on a glass substrate, the glass substrate warps and the plastic part peels off during the heating process and reflow process of the manufacturing process. There was a problem.

JP 2004-88713 A

"Thorough explanation of 2009 camera module", p128-p133, by Hironori Nakajo, published on December 9, 2008

  The present invention provides an imaging lens that can be manufactured in a state free from thermal deformation or the like even by a manufacturing process including a heating step, or has excellent heat resistance in a reflow step, and an imaging lens group and a camera module comprising the imaging lens group. The issue is to provide.

  The present inventors diligently studied the structure of the imaging lens in order to solve the above problems. As a result, in the conventional imaging lens of the above type, the spacer and the lens are in contact with each other for the convenience of the manufacturing process, so that the area of the glass substrate surface where the plastic is in contact is increased. Therefore, the inventors have found that the glass substrate warps and the plastic part is peeled off due to the heat history of the heating process and reflow process of the manufacturing process and the difference in linear expansion between the plastic and glass.

  Based on this knowledge, the inventors of the present invention are imaging lenses in which a plastic lens part and a plastic spacer are formed on at least one surface of a flat glass substrate. An imaging lens in which a total ratio of an area of a portion where the lens portion is in contact with the glass substrate and an area of a portion where the spacer is in contact with the glass substrate to a surface area is 50% or less, It has been found that it has excellent heat resistance against the manufacturing process and solder reflow process.

  In the imaging lens of the present invention, it is preferable that the lens portion and the spacer are not in contact with each other on the surface of the glass substrate.

  In the imaging lens of the present invention, it is preferable that the spacer is in contact with the glass substrate at a plurality of locations on the surface of the glass substrate.

  In the imaging lens of the present invention, the lens part formed on one surface of the glass substrate has a convex lens surface, and the lens part formed on the other surface has a concave lens surface. preferable.

  In the imaging lens according to the aspect of the invention, it is preferable that the spacer has an alignment unit for aligning the imaging lens surface direction and the imaging lens direction when the imaging lenses are stacked.

  Moreover, an imaging lens group can be produced by superimposing the imaging lenses.

  A camera module can be manufactured using this imaging lens group. Furthermore, a mobile phone, a personal computer, a portable information communication device, a digital camera, an automobile, a security camera, and the like equipped with this camera module can be manufactured.

  According to the present invention, an imaging lens having excellent heat resistance in a manufacturing process and a solder reflow process, an imaging lens group including the imaging lens, a camera module using the imaging lens group, and a product such as a mobile phone equipped with the camera module are provided. Can be provided.

FIG. 1A is a front view of the imaging lens 1. FIG. 1B is a plan view of the imaging lens 1. FIG. 2A is a plan view of the imaging lens 11. FIG. 2B is a plan view of the imaging lens 21. FIG. 3A is a plan view of the imaging lens group 61. FIG. 3B is a cross-sectional view of the imaging lens group 61 taken along the line AA. FIG. 4A is a front view of the imaging lens 41. FIG. 4B is a plan view of the imaging lens 41. FIG. 5A is a front view of the imaging lens 51. FIG. 5B is a plan view of the imaging lens 51.

Imaging Lens The imaging lens according to the present invention is formed by forming a plastic lens portion and a plastic spacer on at least one surface of a glass substrate. In this imaging lens, in each surface of the glass substrate, with respect to the area of the surface, the area of the portion where the lens portion is in contact with the glass substrate and the portion where the spacer is in contact with the glass substrate The total ratio with the area is 50% or less.

Hereinafter, the present invention will be specifically described.
(Structure of imaging lens)
FIG. 1 shows an imaging lens 1 which is a specific example of the imaging lens according to the present invention. FIG. 1A is a front view of the imaging lens 1, and FIG. 1B is a plan view of the imaging lens 1.

  The imaging lens 1 includes a glass substrate 2, a lens portion 3 a and a lens portion 3 b, and eight spacers 4. Four of the lens portion 3 a and the eight spacers 4 are provided on the upper surface of the glass substrate 2, and the remaining four of the lens portion 3 b and the eight spacers 4 are provided on the lower surface of the glass substrate 2. It has been.

  In the imaging lens 1, the glass substrate 2 is a flat plate having a square planar shape. A lens portion 3 a and a lens portion 3 b are provided at the center of the glass substrate 2 so as to sandwich the glass substrate 2. The lens portions 3a and 3b are made of plastic. The shape of the portion where the lens portions 3a and 3b are in contact with the glass substrate 2 is circular. The lens portion 3 a has a spherical shape that is convex upward toward the glass substrate 2. That is, the lens portion 3a has a lens surface that is a convex surface. The lens portion 3 b has a peripheral surface portion that stands from the lower surface of the glass substrate 2 and a lower surface that forms part of a spherical surface that is concave toward the lower side of the glass substrate 2. That is, the lens part 3b has a concave lens surface.

  The eight spacers 4 are made of plastic and have a cylindrical shape. The spacers 4 are respectively provided at the four corners of the upper surface and the lower surface of the glass substrate 2. Two of the eight spacers 4 are provided so as to sandwich the glass substrate 2 between the upper surface and the lower surface of the glass substrate 2 with their axes aligned.

  In the imaging lens of the present invention, within the range permitted from the viewpoint of maintaining the optical performance and structure of the lens, the portion of the surface of the glass substrate where the lens portion is in contact with the glass substrate with respect to the area of the surface. It is preferable that the total ratio of the area and the area of the portion where the spacer is in contact with the glass substrate (hereinafter also simply referred to as area ratio) is smaller. Specifically, the area ratio is preferably 50% or less, and more preferably 40% or less.

  If the area ratio is greater than 50%, the plastic expands and contracts due to the heat history in the heating process and the solder reflow process in the lens manufacturing, causing problems of warping of the glass substrate and peeling of the plastic portion from the glass substrate. That is, when the area ratio is 50% or less, the warpage and peeling can be suppressed, and heat resistance is improved.

  Speaking of the imaging lens 1, the area of the upper and lower surfaces of the glass substrate 2 is S, the area of the upper surface of the glass substrate 2 that is in contact with the lens portion 3a and the area of the lower surface that is in contact with the lens portion 3b. S1 and the area of the portion where the spacer 4 is in contact with the upper and lower surfaces of the glass substrate 2 as Ss,

  It is. When the area ratio on the upper surface of the glass substrate is different from the area ratio on the lower surface, it is preferable that the above relationship is established on both the upper surface and the lower surface of the glass substrate.

  The area ratio is preferably 20% or more from the viewpoint of downsizing the imaging lens unit.

  In the imaging lens of the present invention, it is preferable that the lens portion and the spacer are not in contact with each other on the surface of the glass substrate in terms of further improving the heat resistance. In other words, even in the case of an imaging lens having the same area ratio of 50% or less, an imaging lens in which the lens portion and the spacer are not in contact with each other on the surface of the glass substrate has the lens portion and the spacer on the glass substrate. The heat resistance is superior to imaging lenses that are in contact with each other. This is because the linear expansion coefficient is different between the glass substrate and the plastic that is the material of the lens part and the spacer, so the smaller the diameter length of the part in contact with the plastic on the glass substrate surface is, the closer the glass substrate is to the plastic. This is considered to be advantageous in terms of sex. The above effect is obtained as long as the lens portion and the spacer are not in contact with each other on the surface of the glass substrate, and may be in contact with each other at a position away from the surface of the glass substrate.

  Regarding the imaging lens 1, the lens portion 3 a and the four spacers 4 are not in contact with each other on the upper surface of the glass substrate 2, and the lens portion 3 b and the four spacers 4 are in contact with each other on the lower surface of the glass substrate 2. Not. For this reason, the imaging lens 1 includes the glass substrate 2, the lens portion 3a, the lens portion 3b, and the eight spacers 4 in the same manner as the imaging lens 1, but at least one of the spacers 4 is the lens portion 3a or the lens portion. The heat resistance described above is superior to 3b or both, and an imaging lens in contact with each other on the upper surface or the lower surface of the glass substrate 2 or both.

  For the same reason as described above, the spacer is preferably in contact with the glass substrate at a plurality of locations on the surface of the glass substrate. That is, even if the area of the portion in contact with the spacer is the same on the surface of the glass substrate, the heat resistance is improved in an embodiment in which two or more portions are present rather than an embodiment in which the portion is one. As such an aspect, the spacer itself may be divided into a plurality of parts, each of which may be in contact with the glass substrate, or may be an aspect in which one spacer is in contact with a plurality of locations on the glass substrate. Good.

As for the imaging lens 1, four spacers 4 are provided on the upper and lower surfaces of the glass substrate 2 without contacting each other. That is, in the imaging lens 1, the spacers are in contact with each other at four locations on the upper surface and the lower surface of the glass substrate. For this reason, the imaging lens 1 includes a glass substrate 2, a lens portion 3 a, a lens portion 3 b, and eight spacers 4, similar to the imaging lens 1, but two or more of the spacers 4 are the upper surface of the glass substrate 2. Alternatively, the heat resistance is superior to imaging lenses that are in contact with each other on the lower surface or both.
(Glass substrate)
The glass substrate in the imaging lens of the present invention is a member that holds the lens portion and the spacer. The glass substrate is not particularly limited as long as it is a glass substrate used for ordinary optical components, electronic components and displays, and examples thereof include FK glass, BK glass, LaK glass, TEMPAX glass, D263T glass, and B270 glass. It is done.

  The thickness of the glass substrate is arbitrarily determined by the optical design described later, and is usually 200 μm to 800 μm. If the glass is thinner than 200 μm, problems of warpage and crushing are likely to occur, and if it is thicker than 800 μm, the optical performance of the lens may be lowered.

  Although the planar shape of the glass substrate 2 in the imaging lens 1 is a square, in the imaging lens of the present invention, the planar shape of the glass substrate is arbitrarily determined by the optical design described later, and may be a rectangle, a circle, or the like in addition to a square. There may be.

The size of the glass substrate is also arbitrarily determined by the optical design described later, and when the planar shape is a square, the length of one side is usually 2 mm to 10 mm.
(Lens part)
The lens portion in the imaging lens of the present invention is a member that exhibits an optical effect in the imaging lens. The material of the lens part is plastic. The plastic forming the lens part is not particularly limited as long as it is a plastic having sufficient transparency and refractive index as a lens, but from the viewpoint of processability to an uneven surface shape, a thermoplastic transparent plastic, a thermosetting transparent plastic, and A photocurable transparent plastic is preferred.

  When a plastic having a linear expansion coefficient of 40 ppm / ° C. to 100 ppm / ° C. is used as the transparent plastic used in the lens portion of the present invention, a glass substrate, a plastic lens portion, and a plastic spacer portion are used. When the area ratio is as described above, warping and peeling can be suppressed, and heat resistance is improved. Most preferably, it is 60-90 ppm / degrees C.

  In order to have heat resistance that does not change the optical characteristics in the solder reflow process, Tg is preferably 100 ° C. or higher, preferably 120 ° C. or higher, more preferably 140 ° C. or higher.

  As the thermoplastic transparent plastic, a thermoplastic plastic having transparency when molded into a lens shape can be used without particular limitation. Specifically, cyclic olefin plastics suitable for optical applications, acrylic plastics such as polymethyl methacrylate plastics, polycarbonate plastics, polyester plastics, polyarylate plastics, polysulfone plastics, polyethersulfone plastics, polyparaphenylene plastics, polyarylene ethers Examples thereof include phosphine oxide plastic, polyimide plastic, polyetherimide plastic, and polyamideimide plastic.

  As the thermosetting transparent plastic, a thermosetting plastic having transparency when molded into a lens shape can be used without any particular limitation. Specifically, epoxy plastic, silicone plastic, acrylic plastic, etc. suitable for optical applications, etc. Is mentioned.

  As the photocurable transparent plastic, a photocurable plastic having transparency when molded into a lens shape can be used without particular limitation, and specific examples include epoxy plastics and acrylic plastics suitable for optical applications. .

  Among these, the optical characteristics and processing characteristics of lenses are particularly excellent, so cyclic olefin plastics such as COP (Cyclic Olefin Polymer) and COC (Cyclic Olefin Copolymer), polycarbonate plastic, polyester plastic, and thermosetting silicone plastic. Light (UV) curable epoxy plastic and light (UV) curable acrylic plastic are preferable.

  The diameter, height, and shape of the lens unit can be arbitrarily determined by optical design calculation from the sensor size, pixel size, and performance (number of pixels) of the imaging sensor of the camera module that includes the imaging lens. Usually, the lens diameter is in the range of 1 to 5 mm, and the lens height is in the range of 50 to 1000 μm. The shape is usually convex or concave like the lens portion 2a and lens portion 2b in the imaging lens 1, and the lens portion formed on one surface of the glass substrate has a convex lens surface, and the other It is preferable that the lens portion formed on the surface of the lens has a concave lens surface in that the imaging performance of the lens is improved and a clear image can be obtained when the lens and the lens group are incorporated in a camera module. .

  The diameter, height, and shape of the lens portions formed on both surfaces of the glass substrate may be the same or different. However, since the volume of the lens part formed on the upper surface of the glass substrate is the same as that of the lens part formed on the lower surface, the distortion of the glass substrate is suppressed by suppressing the asymmetry of the thermal distortion occurring above and below the glass substrate. It is preferable at the point which can suppress.

The lens portion is usually formed on both sides of the glass substrate, but may be formed only on one side of the glass substrate.
(spacer)
The spacer in the imaging lens of the present invention is provided to maintain a predetermined distance between the lens portions formed in the two imaging lenses adjacent to each other when two or more imaging lenses are stacked. It is a member.

  The material of the spacer in the imaging lens of the present invention is plastic. As the plastic forming the spacer, Tg is 100 ° C. or higher, preferably 120 ° C. or higher, and more preferably 120 ° C. or higher in order to have heat resistance without dimensional change in the solder reflow process. Is preferably 140 ° C. or higher, and examples thereof include the same plastics used for lens formation. Other examples include heat-resistant engineering plastics such as liquid crystal polymer (LCP), polyphenylene sulfide plastic (PPS), polyetheretherketone plastic (PEEK), and polyphthalamide (PPA). The plastic forming the lens portion and the plastic forming the spacer may be the same or different.

  The height of the spacer is arbitrarily determined by optical design calculation from the sensor size, pixel size, and performance (number of pixels) of the imaging sensor of the camera module including the imaging lens, and is usually 100 to 1000 μm.

  The shape of the spacer is not particularly limited as long as the conditions of the imaging lens structure are satisfied. Specifically, a cylindrical shape, a prismatic shape, a cylindrical shape, and the like are preferable from the viewpoint of ease of manufacture. An imaging lens 1 having a cylindrical spacer 4 is as shown in FIG.

  A plan view of the imaging lens 11 having a prismatic spacer is shown in FIG. The imaging lens 11 includes a glass substrate 2, a lens portion 3 a and a lens portion 3 b, and eight spacers 14. About the glass substrate 2, the lens part 3a, and the lens part 3b, it is the same as that of the case of the imaging lens 1. FIG. The spacer 14 is a quadrangular prism type, and is installed at a position corresponding to the spacer 4 in the imaging lens 1.

  A plan view of the imaging lens 21 having a cylindrical spacer is shown in FIG. The imaging lens 21 includes a glass substrate 2, a lens unit 3 a and a lens unit 3 b, and two spacers 24. About the glass substrate 2, the lens part 3a, and the lens part 3b, it is the same as that of the case of the imaging lens 1. FIG. The spacer 24 is a cylindrical type. The spacer 24 is installed on the upper surface of the glass substrate 2 so as to surround the lens portion 3 a with its one end opening being in contact with the glass substrate 2. Similarly, the spacer 24 is installed on the lower surface of the glass substrate 2 so as to surround the lens portion 3b.

  The shape of the spacer provided on the upper surface of the glass substrate and the shape of the spacer provided on the lower surface may be the same or different.

  The spacers need not have a constant cross-sectional area parallel to the glass substrate in a direction perpendicular to the glass substrate plane, and may be different as long as the object of the present invention is achieved. For example, the area of the cross section of the spacer may gradually decrease or increase in the vertical direction from the surface of the glass substrate, or the shape thereof may change. Therefore, the shape may be such that a cross section parallel to the glass substrate is divided into a plurality of sections as it goes toward the glass substrate surface. If the spacer is divided in this way, even if it is a single spacer, the spacer can be installed at a plurality of locations on the surface of the glass substrate. Since the contact area is reduced and the spacer can be brought into contact with the glass substrate at a plurality of locations on the surface of the glass substrate, the heat resistance of the imaging lens can be improved.

  The number of spacers is not particularly limited as long as the above functions of the spacer are ensured, and even if two or more spacers are provided on the upper and lower surfaces of the glass substrate, respectively, like the imaging lens 1 and the imaging lens 11. As in the case of the imaging lens 21, one spacer may be provided on each of the upper surface and the lower surface of the glass substrate. However, as described above, it is preferable that the spacer is divided and installed on the surface of the glass substrate. That is, when the total installation area of the spacers on the glass substrate is the same, the imaging lens having a plurality of spacers is more advantageous in terms of the heat resistance than the imaging lens having one spacer. When a plurality of spacers are provided on the upper surface or the lower surface of the glass substrate, the shape of each spacer may be the same and different.

  In addition, the spacer of the imaging lens of the present invention has an alignment portion for facilitating alignment in the imaging lens surface direction and the imaging lens direction when the imaging lenses are overlapped to form a lens group. It is preferable. FIG. 3A shows a plan view of an imaging lens group 61 formed by superimposing three imaging lenses 31 as a specific example of the imaging lens having a spacer having an alignment portion. 3B is a cross-sectional view of the imaging lens group 61 taken along the line AA in FIG.

  The imaging lens 31 includes a glass substrate 2, a lens portion 3a and a lens portion 3b, four spacers 34a, and four spacers 34b. The lens portion 3 a and the four spacers 34 a are provided on the upper surface of the glass substrate 2, and the lens portion 3 b and the four spacers 34 b are provided on the lower surface of the glass substrate 2. About the glass substrate 2, the lens part 3a, and the lens part 3b, it is the same as that of the case of the imaging lens 1. FIG. The spacer 34 a and the spacer 34 b are installed at positions corresponding to the spacer 4 in the imaging lens 1.

  The spacer 34a includes a columnar support portion 34aI installed on the glass substrate 2, and an alignment portion 34aII provided on the upper surface thereof, which is a convex portion having a cross-sectional shape parallel to the glass substrate 2. . The spacer 34b includes a columnar support portion 34bI installed on the glass substrate 2 and an alignment portion 34bII provided on the lower surface thereof. The alignment part 34bII is a hollow cylinder whose cross-sectional shape parallel to the glass substrate 2 extends from the top surface to the bottom surface of a cylindrical body having a peripheral surface that forms one peripheral surface together with the peripheral surface of the support portion 34bI. It is a part formed. The alignment portion 34aII and the alignment portion 34bII are designed to be fitted. Further, when the alignment portion 34aII and the alignment portion 34bII are fitted and the upper surface of the alignment portion 34aII is in contact with the lower surface of the support portion 34bI, the lower surface of the alignment portion 34bII is in contact with the upper surface of the support portion 34aI. When the alignment portion 34aII of the spacer 34a and the alignment portion 34bII of the spacer 34b are fitted, the spacer 34a and the spacer 34b form one cylinder.

  When the two imaging lenses 31 are overlapped, the cross-shaped convex portions 34aII of the four spacers 34a included in one imaging lens 31 are respectively aligned with the cross-shaped concave portions 34bII of the four spacers 34b included in the other imaging lens 31. By fitting, an imaging lens group including two imaging lenses 31 is formed. Similarly, another imaging lens 31 is superimposed on the imaging lens group to form an imaging lens group 61 including three imaging lenses 31. Similarly, an imaging lens group including four or more imaging lenses 31 can be formed by superimposing the imaging lens 31 on the imaging lens group 61.

  Similar to the imaging lens 31, even when the alignment is performed by fitting the alignment portion having the concave portion and the alignment portion having the convex portion, the alignment portion and the convex portion having the concave portion in one imaging lens It is not necessary to provide both of the alignment unit having a concave portion, and the imaging lens having only the alignment portion having the concave portion and the imaging lens having only the alignment portion having the convex portion are overlapped alternately. And an imaging lens group may be formed.

  As in the alignment portion 34aII and the alignment portion 34bII, in the alignment portion having the concave portion and the alignment portion having the convex portion, the sectional shape of the concave portion and the convex portion is not particularly limited, and the alignment portion 34aII and In addition to the cross shape such as the alignment portion 34bII, a circular shape, a triangular shape, a square shape, an X shape, an L shape, or the like may be used. The cross-sectional shape of the concave and convex portions of the alignment portion is preferably a cross shape.

  In addition, the alignment unit in the imaging lens according to the present invention may be of a type other than the above-described fitting type as long as the alignment and optical axis alignment in the lens surface direction of each imaging lens can be facilitated. It doesn't matter.

The number of alignment portions included in the imaging lens of the present invention is not particularly limited as long as alignment in the lens surface direction and optical axis alignment of each imaging lens can be facilitated. When the imaging lens has a plurality of alignment portions, the shape and style of each alignment portion may be the same or different.
(Other components)
In the imaging lens of the present invention, in order to improve the performance of the imaging lens, in order to prevent light scattering and irregular reflection outside the effective surface of the lens, a light shielding layer may be formed on a portion other than the effective surface of the glass substrate surface. Examples of the material of the light shielding layer include a plastic in which a metal and a light shielding material are dispersed. The metal light-shielding layer can be provided without particular limitation as long as it is a portion other than the effective surface of the glass substrate surface, for example, between the glass substrate outside the effective surface of the imaging lens of the present invention and the lens portion and the spacer, It can be formed by adhering to a glass substrate. The plastic light-shielding layer is provided in a portion other than the effective surface of the glass substrate surface without being adhered to the glass substrate. For example, a light-shielding layer formed by hollowing out a part from a layer covering the entire surface of the glass substrate so as not to cover the lens optical surface can be provided so as to cover the lens part.

  Here, the “effective surface of the glass substrate surface” and the “effective surface of the imaging lens” mean that the imaging lens of the present invention and the lens group thereof are mounted on the camera module and imaged from the real image side to the imaging sensor side. This is the surface through which the light bundle passes. The “effective surface of the glass substrate surface” and the “effective surface of the imaging lens” can be obtained in advance by optical design of the lens shape.

  Examples of the metal used for the light shielding layer include trivalent chromium and alumite. Examples of the method for forming the metal light-shielding layer include methods such as plating and anodic oxidation.

  As the plastic used for the light shielding layer, after dispersing carbon particles etc. as a light shielding material in polyester, polyimide, cyclic olefin plastic, fluorine plastic, etc., on the film, on the plastic film, Examples thereof include those coated with acrylic plastic, epoxy plastic or the like in which the light shielding material is dispersed. Examples of a method for forming a plastic light-shielding layer include a method of attaching the light-shielding plastic film to the upper surface of the lens.

  The thickness of the light shielding layer is not particularly limited as long as the above functions are ensured, and is usually 0.1 to 10 μm in the case of a metallic light shielding layer and 5 to 100 μm in the case of a film-like plastic.

  Further, a light shielding sheet or a light shielding plate may be placed outside the effective surface between the imaging lenses of the imaging lens group.

In the imaging lens of the present invention, an AR coating (Anti-Reflection treatment coating) for preventing light reflection on the lens surface may be formed to improve performance. For example, AR coating is performed by forming two or more low-refractive layers and high-refractive-index layers on the surface of the lens portion by sputtering or the like.
(Method for manufacturing imaging lens)
The manufacturing method of the imaging lens of the present invention is not particularly limited as long as the structure of the imaging lens of the present invention is formed. As a method for forming the lens portion, the imprint method is most preferable because it is simple.

  Specifically, as a method of forming a lens, when the plastic forming the lens is a thermoplastic, first, a thermoplastic sheet, pellet or powder is melted and fixed to one or both sides of the glass substrate, or It fixes by dripping or coating the solution which melt | dissolved the thermoplastic plastic, and drying. Next, a lens portion having a desired shape is formed on the surface of the glass substrate by thermal imprinting using a mold corresponding to the desired lens shape.

  When the plastic forming the lens is a thermosetting plastic, a plastic liquid layer is formed on the glass substrate by dropping or coating the plastic liquid before curing onto the glass substrate, and a mold corresponding to the desired lens shape A lens part having a desired shape is formed on the surface of the glass substrate by thermal imprinting.

  When the plastic forming the lens is a photo-curable plastic, a plastic liquid layer is formed on the glass substrate by dropping or coating the plastic liquid before curing onto the glass substrate, and a transparent gold corresponding to the desired lens shape. A lens part having a desired shape is formed on the surface of the glass substrate by optical imprinting using a mold.

Examples of the method for forming the spacer include a method in which a plastic previously molded into a spacer shape is bonded to a predetermined position on a glass substrate with a UV adhesive or the like, and a method in which the molded body is heated and fused. The plastic forming the spacer is preferably the same as the plastic forming the lens portion, and the method of forming the spacer by imprint molding simultaneously with the imprint molding of the lens portion is preferable because the number of steps is small and the position adjustment is easy.
Imaging Lens Group The imaging lens group of the present invention is formed by overlapping the imaging lenses. FIG. 3 shows an imaging lens group 61 as a specific example of the imaging lens group of the present invention. In the imaging lens group 61, a plurality of imaging lenses are superposed using a positioning unit. However, in the imaging lens group of the present invention, as long as a desired optical function is ensured, the method of superimposing imaging lenses is not limited. There are no particular restrictions. The number of imaging lenses to be superimposed can be appropriately determined according to the purpose.

  The imaging lens group of the present invention can be used for a camera module or the like.

  The camera module using the imaging lens group of the present invention can be mounted on products such as a mobile phone, a personal computer, a portable information communication device, a digital camera, an automobile, and a security camera. By mounting this camera module on these products, the productivity of these products can be improved.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example, this invention is not limited to these Examples at all.

Evaluation of solder reflow resistance Solder reflow resistance was evaluated as follows using a reflow furnace (STR-2010N2M-III type) manufactured by Senju Metal Industry Co., Ltd.
(Temperature setting)
About reflow temperature setting, it set as follows based on JEDEC specification J-STD-020D.

Conveyor speed: 25.3 cm / min
Temperature setting for each heating zone 1st zone: 305 ° C
Second zone: 240 ° C
Third zone: 240 ° C
Fourth zone: 245 ° C
Zone 5: 318 ° C
(Real side temperature in reflow furnace)
Preheating region (150 ° C. to 200 ° C.): 100 seconds Temperature region above lead-free solder melting temperature (217 ° C.): 114 seconds Temperature region above 255 ° C .: 34 seconds Maximum temperature: 265 ° C.
Heating time from room temperature to maximum temperature: 5 minutes 05 seconds Lead-free solder melting temperature (217 ° C) → Temperature rise rate to 255 ° C: 1.4 ° C / second 255 ° C → Cooling to solder melting temperature (217 ° C) Speed: 1.7 ° C / second (reflow furnace passage test)
After the temperature in the furnace was stabilized, the lens sample was placed on a glass epoxy substrate, the sample was fixed with an imide tape, and placed on a conveyor of the reflow furnace so that the lens sample was directly heated, and passed through the furnace. This operation was performed three times.
(Test evaluation)
The lens sample that passed through the reflow furnace was checked for warpage of the glass substrate of the lens with a shape measuring instrument (Talor Hobson Precision, Form Taly Surf Series 2).

Further, the interface between the glass substrate and the lens part was observed with a microscope (manufactured by Keyence Corporation), and the adhesion between the glass substrate and the lens part (presence or absence of peeling of the lens part from the glass substrate) was evaluated.
(Example)
ARTON (manufactured by JSR, linear expansion coefficient: 69 ppm / K, Tg: 165), which is a cyclic olefin plastic as a plastic for forming lenses and spacers, on both surfaces of a D263T glass (manufactured by Shot) having a thickness of 0.3 mm as a glass substrate 25 wt% toluene solution at a temperature of 1.1 ° C. in a portion of the glass substrate where the lens portion and spacer portion are formed, and the amount of plastic after drying is 1.1 times the design amount necessary to form the lens and spacer. The mixture was added dropwise and heated at 80 ° C. for 12 hours under vacuum. Next, using a thermal imprint apparatus and a mold for imprinting so as to form an imaging lens as shown in FIG. 4, press molding is performed at 205 ° C. for 10 minutes to produce the imaging lens 41 shown in FIG. did.

  FIG. 4A is a front view of the imaging lens 41, and FIG. 4B is a plan view of the imaging lens 41. The imaging lens 41 includes a glass substrate 42, a lens portion 43 a that is a convex lens, a lens portion 43 b that is a concave lens, and eight columnar spacers 44. The basic structure of the imaging lens 41 is the same as that of the imaging lens 1.

The size of the glass substrate 42: 4 mm × 4 mm × 0.3 mm
Diameter of lens part 43a and lens part 43b: 2 mm
Lens part 43a height: 0.3 mm
Lens part 43b height: 0.4 mm
Spacer 44 diameter: 1 mm
Spacer 44 height: 0.5 mm
The area ratio of the lens portion of the obtained imaging lens 41 and the plastic portion of the spacer was 39% on both the upper surface and the lower surface.

As a result of evaluation of reflow resistance of the obtained lens, warpage of the glass substrate and peeling between the plastic and the glass substrate were not observed.
(Comparative example)
In the example, an imaging lens 51 shown in FIG. 5 was created in the same manner except that the amount of dropped plastic and the mold were changed so that the imaging lens shown in FIG. 5 was obtained.

  FIG. 5A is a front view of the imaging lens 51, and FIG. 5B is a plan view of the imaging lens 51. The imaging lens 51 includes a glass substrate 52, a lens portion 53 a that is a convex lens, a lens portion 53 b that is a concave lens, and two spacers 54. The glass substrate 52 is the same as the glass substrate 42 of the imaging lens 41. The lens portion 53a and one spacer 54, and the lens portion 53b and another spacer 54 are integrally formed. The spacer 54 includes a flat plate portion 54a and a prismatic portion 54b. The flat plate portion 54 a has a square planar shape, and the length of one side thereof is shorter than the length of one side of the upper surface and the lower surface of the glass substrate 52. The prismatic part 54b is a quadrangular prism, and four prismatic parts 54b are respectively provided at the four corners of the upper surface of the flat plate part 54a. One spacer 54 is on the upper surface of the glass substrate 52, each side of the upper surface of the flat plate portion 54 a is parallel to one side of the upper surface of the glass substrate 52, and the distance between the four sets of parallel sides is the same. Are arranged as follows. Similarly, another spacer 54 is disposed on the lower surface of the glass substrate 52. A lens portion 53 a is formed at the center of the flat plate portion 54 a of the spacer 54 disposed on the upper surface of the glass substrate 52. A lens portion 53 b is formed at the center of the flat plate portion 54 a of the spacer 54 disposed on the lower surface of the glass substrate 52.

The size of the glass substrate 52: 4 mm × 4 mm × 0.3 mm
Diameter of lens part 53a and lens part 53b: 2 mm
Lens part 53a height: 0.3 mm
Lens part 53b height: 0.4 mm
Spacer 54 diameter: 1 mm
The thickness of the flat plate portion 54a: 0.5 mm
Size of the surface of the glass substrate 52 where the lens portion 53a, the lens portion 53b, and the spacer 54 are in contact: 3.65 mm × 3.65 mm
The area ratio of the lens portion of the imaging lens 51 and the plastic portion of the spacer was 83% on both the upper surface and the lower surface.

  As a result of reflow evaluation of the obtained lens, warpage of the glass substrate and peeling between the plastic and the glass substrate were observed.

  From the above, the heat resistance improves as the total ratio of the area of the part where the lens part is in contact with the glass substrate and the area of the part where the spacer is in contact with the glass substrate to the area of the glass substrate is smaller I found out that

  The imaging lens of the present invention, which is superior in heat resistance compared to a conventional imaging lens in which a plastic lens part and a plastic spacer are formed on both surfaces of a flat glass substrate, is mounted on a mobile phone, a mobile personal computer, etc. It can be used as a lens for a small camera module, and is particularly suitable for an imaging lens that requires durability in a solder reflow process.

DESCRIPTION OF SYMBOLS 1 Imaging lens 2 Glass substrate 3a, 3b Lens part 4 Spacer 11 Imaging lens 14 Spacer 21 Imaging lens 24 Spacer 31 Imaging lens 34a, 34b Spacer 34aI Support part 34aII Positioning part 34bI Supporting part 34bII Positioning part 41 Imaging lens 42 Glass board 43a Lens unit 43b Lens unit 44 Spacer 51 Imaging lens 52 Glass substrate 53a Lens unit 53b Lens unit 54 Spacer 54a Flat plate unit 54b Square column unit 61 Imaging lens group

Claims (13)

  An imaging lens in which a lens portion made of plastic and a spacer made of plastic are formed on at least one surface of a glass substrate, and the lens portion is in each surface of the glass substrate, and the lens portion corresponds to the surface of the glass substrate. An imaging lens, wherein a total ratio of an area of a contact portion and an area of a portion where the spacer is in contact with the glass substrate is 50% or less.   The imaging lens according to claim 1, wherein the lens portion and the spacer are not in contact with each other on the surface of the glass substrate.   The imaging lens according to claim 1, wherein the spacer is in contact with the glass substrate at a plurality of locations on the surface of the glass substrate.   The lens portion formed on one surface of the glass substrate has a convex lens surface, and the lens portion formed on the other surface has a concave lens surface. 4. The imaging lens according to any one of 3.   5. The imaging lens according to claim 1, wherein the spacer includes an alignment unit for aligning the imaging lens surface direction and the imaging lens direction when the imaging lenses are stacked.   An imaging lens group comprising the imaging lenses according to claim 1 superimposed on each other.   A camera module using the imaging lens group according to claim 6.   A mobile phone comprising the camera module according to claim 7.   A personal computer comprising the camera module according to claim 7.   A portable information communication device comprising the camera module according to claim 7.   A digital camera comprising the camera module according to claim 7.   An automobile equipped with the camera module according to claim 7.   A security camera comprising the camera module according to claim 7.

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