WO2013084475A1 - Lens unit and method for manufacturing same - Google Patents

Abstract

The present invention pertains to a lens unit manufacturing method that addresses the need for providing a lens unit with high optical performance while reducing manufacturing cost. When a lens optical surface is to be formed using the lens unit manufacturing method of the present invention, either a PNP method or a NPNP method is selected in accordance with the configuration and positional tolerance of the lens optical surface, and either a direct method or a step and repeat method is selected. One or two or more of the resulting wafer lenses is stacked with another member and the resulting assembly is divided in lens units to obtain the lens units.

Description

Lens unit manufacturing method and lens unit

The present invention relates to a method of manufacturing a lens unit having a plurality of lens optical surfaces arranged side by side in the optical axis direction, and a lens unit obtained thereby.

In the field of optical lens manufacturing, a technology for manufacturing an optical lens having high heat resistance by forming a resin layer including a lens portion functioning as an optical lens on the surface of a glass substrate using a curable resin is known. ing. As a method of manufacturing an optical lens to which this technique is applied, a method of manufacturing a so-called “wafer lens” in which a plurality of lens portions made of a curable resin are formed on the surface of a glass substrate has been proposed. After manufacturing the wafer lens, the glass substrate of the wafer lens is cut and divided for each lens portion, whereby a large number of optical lenses can be obtained at one time.

As a method of manufacturing a wafer lens, a curable resin material is interposed between a master mold in which a plurality of negative lens molding surfaces corresponding to the shape of a lens optical surface are arranged and a glass substrate. A method of forming a lens portion made of a curable resin on a glass substrate by curing the material can be mentioned. That is, the shapes of the master mold and the lens portion change in the order of negative shape → positive shape (hereinafter referred to as “NP method”). However, since the master mold is manufactured by cutting a hard base material such as a metal, when the size of the wafer lens is increased (for example, 8 inch diameter), it takes time and effort to process the master mold. Becomes extremely expensive. For this reason, it is actually difficult to adopt the NP method. As another method for producing a wafer lens, there is a method of molding a lens portion made of a curable resin on a glass substrate using an intermediate mold produced using a master mold (for example, Patent Document 1, Patent Document 1). 2).

Patent Documents 1 and 2 describe a method of manufacturing a wafer lens using a master mold and one type of intermediate mold (submaster mold). In this manufacturing method, first, a resin molding having a negative lens molding surface is molded on a substrate using a master molding die having a positive lens molding surface corresponding to the shape of the lens optical surface. Then, a sub master mold is produced. Next, a wafer lens is manufactured by molding a lens portion made of a curable resin on a glass substrate using a submaster mold. That is, the shapes of the master mold, the sub master mold, and the lens portion change in the order of positive shape → negative shape → positive shape (hereinafter referred to as “PNP method”).

Patent Document 2 also describes a method of manufacturing a wafer lens using a master mold and two types of intermediate molds (a sub master mold and a sub sub master mold). In this manufacturing method, first, a resin molded product having a positive lens molding surface is molded on a substrate using a master molding die having a negative lens molding surface corresponding to the shape of the lens optical surface. Then, a sub master mold is produced. Next, by using the sub master mold, a resin molded product having a negative lens molding surface is molded on the substrate, thereby producing a sub sub master mold. Finally, a wafer lens is manufactured by molding a lens portion made of a curable resin on a glass substrate using a sub-submaster mold. That is, the shapes of the master mold, the sub master mold, the sub sub master mold, and the lens portion change in the order of negative shape → positive shape → negative shape → positive shape (hereinafter referred to as “NPNP method”).

In this way, the number of times the master mold is used can be reduced by molding the lens section using the intermediate mold instead of directly molding the lens section using the master mold. As a result, the expensive master mold can be prevented from being deteriorated, and the manufacturing cost can be reduced.

Usually, the sub-master mold is a) a dispensing process in which a resin material is supplied onto the substrate or the master mold, and b) the master mold and the substrate are brought close to each other to follow the shape of the molding surface of the master mold. A sandwiching step of sandwiching the resin material between the two, c) a solidification step of solidifying the resin material sandwiched between the master mold and the substrate, and d) separating the master mold and the substrate and bonding them to the substrate The molded resin product is manufactured by a molding process including a mold release process for releasing the resin molded product from the master mold. As a manufacturing method of the sub master mold, a “direct method (collective molding method)” and a “step and repeat method” are assumed.

In the “direct method (batch molding method)”, for example, when a wafer lens is manufactured using a disk-shaped glass substrate (glass wafer) having an 8-inch diameter, a large (full wafer size) having a diameter larger than this is used. By using the master mold, the dispensing process, the clamping process, the solidifying process, and the mold releasing process are performed once to produce a sub master mold. In this case, the number of lens molding surfaces equal to or greater than the number of lens molding surfaces formed on the sub-master molding die (for example, 5000) is formed on the master molding die. On the other hand, in the “step-and-repeat method”, a sub-master mold is produced by repeating a dispensing process, a clamping process, a solidifying process, and a mold releasing process using a small master mold (see, for example, Patent Document 3). ). In this case, the master mold has a smaller number (for example, 1 to 100) of lenses than the number of lens portions of the wafer lens to be manufactured (that is, the number of lens molding surfaces formed on the sub-master mold). A molding surface is formed.

JP 2011-51132 A JP 2009-226638 A International Publication No. 2007/140643

In recent years, imaging lenses mounted on portable electronic devices such as mobile phones, smartphones, and tablet terminals are also required to have high optical performance. From the object side to the image side for high performance. A lens unit having a configuration in which a plurality of lens optical surfaces are arranged side by side is adopted. Such a lens unit having a plurality of lens optical surfaces can be configured by combining a plurality of types of lens portions obtained by dividing a wafer lens. For example, a first wafer lens and a second wafer lens are respectively produced and bonded together with a spacer interposed therebetween, and the obtained laminated body is divided for each lens unit. A lens unit having a lens optical surface can be manufactured.

Thus, in a lens unit having a plurality of lens optical surfaces arranged in the optical axis direction, particularly a lens unit obtained by laminating a plurality of wafer lenses, the desired optical performance is obtained because the number of lens optical surfaces is large. Therefore, it is required that each lens optical surface is accurately reproduced in an intended shape and is correctly arranged at an intended position.

(PNP and NPNP methods)
The NPNP method is advantageous in terms of reproducibility of the lens shape, although it is advantageous in terms of cost because it undergoes two transfers to obtain a sub-submaster mold. For this reason, when all the lens optical surfaces of the lens unit having a plurality of lens optical surfaces described above are manufactured by the NPNP method, there is a problem that it is difficult to obtain sufficient required performance as the entire lens unit. On the other hand, in such a lens unit having a plurality of lens optical surfaces, since the functions required for each lens optical surface are different, the shape of each lens optical surface is different. For example, in an imaging lens unit mounted on an imaging device, in order to prevent the occurrence of shading, in order to reduce the chief ray incident angle of the light beam that forms an image on the imaging surface of the imaging device, the lens optics located closest to the image side It is required to increase the effective diameter of the surface. For this reason, the lens optical surface on the most image side has a relatively large tolerance for the shape and position, and even if manufactured by the NPNP method, the optical performance of the lens unit as a whole is unlikely to deteriorate. That is, there is room for adopting the NPNP method depending on the lens optical surface.

In recent years, there has been a strong demand for miniaturization of lens units. Here, in the case where the uneven shape is formed around the lens portion, if the size of the lens unit is to be reduced, the uneven shape around the lens portion must be made fine. For this reason, it is becoming difficult to create a master mold.

For example, when a lens part is molded by individually placing a resin material on each lens molding surface of the mold for molding the lens part, the spread of the resin material around the lens part during molding of the lens part is controlled. In order to do so, an annular protrusion may be formed on the mold. In this case, as a result of molding, an annular concave portion is formed around the lens portion, reflecting the convex shape of the molding die. In addition, for the purpose of preventing scratches on the lens optical surface, protrusions serving as leg portions may be formed around the lens portion. Also in this case, a concave portion is formed between the lens portion and the leg portion. As described above, of the plurality of lens optical surfaces included in the imaging lens unit, the lens optical surface located closest to the image side is required to have an increased effective diameter. However, in order not to increase the size of the lens unit, it is necessary to reduce the size of the peripheral portion. Therefore, the concave portion formed around the lens optical surface is very fine and steep. .

When manufacturing a wafer lens having a plurality of lens portions each having the above-described concave portion formed by using a positive master mold (mold) and a negative sub-master mold (resin mold) (PNP format) It is necessary to provide a recess corresponding to the above-described recess on the molding surface of the positive master mold. Thus, in order to provide a fine recess in the master mold, it is necessary to use a tool whose radius of curvature at the tip is smaller than the minimum radius of curvature of the recess. If the minimum curvature radius of these recesses is below the processing limit of currently available tools, the recesses cannot be formed in the master mold.

Also, when producing a master mold, a plurality of lens molding surfaces are repeatedly formed on a single mold, which causes a problem of processing defects due to tool wear. This problem is particularly noticeable when using a tool having a small radius of curvature at the tip. This is because a tool having a small radius of curvature at the tip end is likely to be worn out and the processing time tends to be long. For this reason, in practical use, when a master mold is manufactured, a tip having an excessively small radius of curvature cannot be used, and it becomes more difficult to process a fine recess.

(Direct method and step-and-repeat method)
On the other hand, as described above, as a method for manufacturing a wafer lens, a method of manufacturing a submaster mold by a direct method and a method of manufacturing a submaster mold by a step-and-repeat method are assumed. In the following description, a method of manufacturing a wafer lens using a submaster mold manufactured by the direct method is referred to as a “direct method manufacturing method”, and a submaster mold manufactured by the step-and-repeat method is referred to as a “direct method”. A method of manufacturing a wafer lens using the same may be referred to as a “step-and-repeat manufacturing method”.

Comparing these methods, the direct manufacturing method that simultaneously forms all lens molding surfaces of the sub-master mold is a step-and-repeat method that forms the lens molding surface of the sub-master mold in multiple steps. Compared with this manufacturing method, the accuracy (shape accuracy and position accuracy) of the lens optical surface finally formed is excellent. For this reason, by forming each lens part included in the lens unit with a direct manufacturing method, the shape and position of the lens optical surface is formed as intended, and optical performance that meets the demand for higher performance. Can be manufactured.

However, when the sub-master molds of all the lens parts included in the lens unit are formed by the direct manufacturing method, there arises a problem that the manufacturing cost of the lens unit is greatly increased. That is, in the direct manufacturing method, it is necessary to prepare a large master mold with a full wafer size, but as the number of lens molding surfaces increases, the processing becomes more difficult and the processing time becomes longer. The production of a large master mold used in the process may require several times to 10 times as much time and cost as a small master mold used in the step-and-repeat method. As a result, a large master mold used for the direct method is very expensive. In addition, the lens unit diameter can be reduced to reduce the size of the lens unit, the number of lens units per wafer lens can be increased to increase the number of lens units obtained at one time, and the lens unit height can be increased. If the lens optical surface has a complicated shape to improve performance, or if irregularities are provided around the lens for the purpose of molding or preventing scratches, the difficulty of processing the master mold will increase further. However, the processing of the master mold itself may be substantially difficult.

An object of the present invention is to provide a method of manufacturing a lens unit that can meet a demand for providing a lens unit having high optical performance while suppressing manufacturing cost. Another object of the present invention is to provide a lens unit obtained by this manufacturing method.

In the lens unit having a plurality of lens optical surfaces, the inventor is required to form each lens optical surface in the intended position in the correct position in order to obtain the desired optical performance, The present invention is created by focusing on the fact that there are lens optical surfaces with relatively large tolerances in shape and position because the functions required for each lens optical surface are different and the shape of each lens optical surface is different. It came to. The method of manufacturing a lens unit according to the present invention includes selecting a PNP method and an NPNP method according to the tolerance of the shape and position when forming a lens optical surface, and / or a direct method and One of the step-and-repeat methods is selected.

That is, the manufacturing method of the lens unit of the present invention is a manufacturing method of a lens unit having a plurality of lens optical surfaces including a first lens optical surface and a second lens optical surface arranged side by side in the optical axis direction. The first lens optical surface includes a first master molding die and a resin material having a first molding surface including a plurality of negative lens molding surfaces corresponding to the shape of the first lens optical surface. Forming a first sub master mold having a second molding surface including a plurality of positive lens molding surfaces corresponding to the shape of the first lens optical surface by molding using The third molding surface includes a plurality of negative lens molding surfaces corresponding to the shape of the first lens optical surface by molding using the first sub-master molding die and the resin material. Sub-subma A first resin layer having a first surface including a plurality of the first lens optical surfaces by performing a molding using a sub-submaster molding die and a curable resin material. Forming a first wafer lens manufacturing method, wherein the second lens optical surface includes a plurality of positive lens molding surfaces corresponding to the shape of the second lens optical surface. 5th including a plurality of negative lens molding surfaces corresponding to the shape of the second lens optical surface by molding using a second master molding die having a fourth molding surface and a resin material. Forming a second sub-master mold having a plurality of molding surfaces, and molding the second lens optical surface by using the second sub-master mold and the curable resin material. Containing second surface And forming a second resin layer having, formed by the manufacturing method of the second wafer lens, it is characterized.

The method for manufacturing a lens unit according to the present invention is a method for manufacturing a lens unit having a plurality of lens optical surfaces including a first lens optical surface and a second lens optical surface arranged side by side in the optical axis direction. The first lens optical surface and the second lens optical surface are molded by using a master molding die having a lens molding surface corresponding to the shape of the lens optical surface and a resin material. A step of producing a sub-master mold having a plurality of molding surfaces for lenses corresponding to the shape of the lens optical surface, the sub-master mold, or a sub-sub-master mold produced using the sub-master mold, and curing Forming a wafer lens having a plurality of lens portions including the lens optical surface by molding using a functional resin material. And the first sub-master mold corresponding to the first lens optical surface has a first or second lens molding surface having a shape corresponding to the shape of the first lens optical surface. Using a master mold, one or two or more resin moldings are repeatedly formed to form a plurality of resin moldings on one substrate, and the step-and-repeat method is used to form the second lens optical surface. The corresponding second sub-master mold uses the second master mold having a plurality of lens molding surfaces corresponding to the shape of the second lens optical surface to form all the resin moldings simultaneously. Thus, it is produced by a direct method in which a plurality of resin moldings are formed on one substrate.

The lens unit of the present invention is manufactured by the above-described method for manufacturing a lens unit of the present invention.

According to the present invention, it is possible to manufacture a lens unit that can meet the demand for higher optical performance while suppressing an increase in cost.

FIG. 1A is a sectional view of a lens unit according to the first and fourth embodiments of the present invention, and FIG. 1B is a bottom view of the lens unit according to the first and fourth embodiments. It is. 2A to 2C are cross-sectional views showing a procedure for forming the first resin layer. 3A to 3C are cross-sectional views showing a procedure for forming the second resin layer. 4A to 4D are cross-sectional views showing a procedure for forming the fourth resin layer. It is a top view which shows a mode that a submaster shaping | molding die is formed by a step and repeat system. 6A to 6C are cross-sectional views showing a procedure for forming the third resin layer. 7A to 7D are cross-sectional views showing a procedure for manufacturing the lens unit. 8A to 8C are schematic views showing how a master mold is produced. It is sectional drawing of the lens unit which concerns on the 2nd Embodiment and 5th Embodiment of this invention. FIG. 10A is a cross-sectional view of a lens unit according to the third and sixth embodiments of the present invention, and FIG. 10B is a bottom view of the lens unit according to the third and sixth embodiments. It is.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

In the method of manufacturing a lens unit according to each embodiment of the present invention, when forming a lens optical surface, a manufacturing method (PNP method / NPNP method, direct method / step and step and step and step and operation) is performed according to the tolerance of the shape and position. Select (Repeat method).

(First embodiment)
1A is a cross-sectional view of the lens unit according to the first embodiment (a cross-sectional view taken along line AA shown in FIG. 1B), and FIG. 1B is a bottom view of the lens unit according to the first embodiment. is there. As shown in these drawings, the lens unit 100 of the present embodiment includes a first resin layer 110 including a first lens portion 110a and its peripheral portion 110b, a second lens portion 120a and its peripheral portion 120b. The second resin layer 120 including the third lens portion 130a and the peripheral portion 130b thereof, the fourth resin layer 140 including the fourth lens portion 140a and the peripheral portion 140b thereof. A first substrate 150, a second substrate 160, a first spacer 170, and a second spacer 180.

The first resin layer 110 is formed on one surface of the first substrate 150, and the second resin layer 120 is formed on the other surface of the first substrate 150. Similarly, the third resin layer 130 is formed on one surface of the second substrate 160, and the fourth resin layer 140 is formed on the other surface of the second substrate 160. . A first spacer 170 is disposed between the first substrate 150 and the second substrate 160, and the second resin layer 120 and the third resin layer 130 facing each other are separated from each other. The second spacer 180 is disposed on the surface of the second substrate 160 where the fourth resin layer 140 is formed. The second spacer 180 controls the distance between the fourth resin layer 140 and the imaging surface of an imaging element (not shown).

The lens unit 100 has an adhesive layer for adhering the spacer, and may have a diaphragm, an infrared cut coat, or the like. In addition, the first substrate 150 and the second substrate 160 are used for alignment marks for forming a resin layer including a lens portion on both surfaces of the substrate and for alignment when a wafer lens is laminated as will be described later. An alignment mark may be provided. For convenience of explanation, illustration and explanation thereof are omitted.

The first lens unit 110a, the second lens unit 120a, the third lens unit 130a, and the fourth lens unit 140a are respectively a first lens optical surface 110a ′, a second lens optical surface 120a ′, and a third lens unit. Lens optical surface 130a 'and fourth lens optical surface 140a', and from the object side (upper side in the figure) to the image side (lower side in the figure) so that the optical axes of the lens optical surfaces coincide with each other. Are arranged in order. The shape of each lens optical surface is different depending on the required function. In the present embodiment, the first lens optical surface 110a 'has a convex shape with respect to the object side. The second lens optical surface 120a 'has a concave shape with respect to the image side. The third lens optical surface 130a 'has a convex shape with respect to the object side at the center and a concave shape with respect to the object side. The center of the fourth lens optical surface 140a 'is concave with respect to the image side, and the periphery thereof is convex with respect to the image side. Each of the lens optical surfaces 110a ', 120a', 130a ', and 140a' has an aspherical shape. Further, each lens optical surface 110a ', 120a', 130a ', 140a' has an effective diameter and an outer diameter that increase in order from the object side. The peripheral portions 110b, 120b, 130b, and 140b include annular recesses C1, C2, C3, and C4, which will be described later. Each peripheral surface 110b ′, 120b ′, 130b ′, 140b ′ and each lens optical surface 110a ′, 120a ′, 130a ′, 140a ′, respectively, a resin layer surface (second surface) 110 ′, 120 ', 130' and the resin layer surface (1st surface) 140 'are comprised.

The tolerance (shape error and position error) of each lens optical surface is different for each lens optical surface. For example, when comparing a lens optical surface with a small effective diameter with a lens optical surface with a large effective diameter, the lens optical surface with a large effective diameter is more affected by the shape and position error of the lens optical surface (deterioration of optical performance). Is relatively small. That is, in the present embodiment, the fourth lens unit 140 positioned closest to the image side has a large allowable error, and the other lens units 110, 120, and 130 have a small allowable error.

The first resin layer 110, the second resin layer 120, the third resin layer 130, and the fourth resin layer 140 are made of a curable resin such as a photocurable resin or a thermosetting resin. Examples of the photocurable resin include acrylic resin, allyl ester resin, and epoxy resin. The acrylic resin and the allyl ester resin can be obtained by radical polymerization of a curable resin material such as an acrylic resin composition or an allyl ester resin composition containing a polymerizable monomer and a radical polymerization initiator. The epoxy resin is obtained by cationic polymerization of an epoxy resin composition containing a polymerizable monomer and a cationic polymerization initiator.

The first substrate 150 and the second substrate 160 are light-transmitting flat plate members or substantially flat plate members. Examples of the substrate include a glass substrate and a transparent resin substrate.

The first spacer 170 and the second spacer 180 are substantially plate-like members having through holes formed at positions corresponding to the lens portions. Examples of the spacer include a resin substrate, a metal substrate, a glass substrate and the like in which through holes are formed by etching or machining.

As indicated by broken lines in FIG. 1A, concentric concave portions C1, C2 are formed in the peripheral portions 110b, 120b, 130b, 140b of the respective lens portions, reflecting the shape of convex portions described later provided in the mold. , C3 and C4 are formed. Further, in order to prevent the occurrence of shading, the fourth lens optical surface 140a ′ located closest to the image side is configured so that the effective diameter thereof is larger than those of the other lens optical surfaces 110a ′, 120a ′, and 130a ′. ing. Furthermore, in order to prevent the overall size of the lens unit from becoming large, the radius of curvature of the concave portion C4 formed around the fourth lens optical surface 140a ′ positioned closest to the image side is set to the other lens optical surfaces 110a ′, The radius of curvature of the recesses C1, C2, and C3 formed around 120a ′ and 130a ′ is set smaller. Specifically, in the present embodiment, the fourth resin layer 140 including the fourth lens portion 140a located closest to the image side includes a recess C4 having a radius of curvature smaller than 0.1 mm. On the other hand, the first resin layer 110, the second resin layer 120, and the third resin layer 130 including the other lens portions 110a, 120a, and 130a include a recess having a radius of curvature of 0.1 mm or more. Does not include a recess smaller than 0.1 mm.

Next, a method for manufacturing the lens unit of this embodiment will be described.

In the manufacturing method of the lens unit of the present embodiment, 1) a first step for producing two or more wafer lenses, and 2) a laminate is obtained by laminating and fixing two or more wafer lenses and other members. A second step, and 3) a third step of dividing the laminated body including the wafer lens for each lens unit.

In the step 1) for producing the wafer lens, first, a sub master mold is produced using a master mold having a lens molding surface corresponding to the shape of the lens optical surface. Next, by performing molding using the obtained sub-master molding die, or a sub-sub-master molding die produced using the sub-master molding die and a curable resin material, a lens portion including the lens optical surface is obtained. A plurality of wafer lenses are produced.

In particular, in the manufacturing method of the lens unit of the present embodiment, in the step of manufacturing the wafer lens of 1), the resin layer (fourth resin layer 140) including the concave portion having a radius of curvature smaller than 0.1 mm is negative. For resin layers (first resin layer 110, second resin layer 110, and third resin layer 130) that are formed using a master molding die and do not include a recess having a radius of curvature of 0.1 mm or less. One feature is that it is formed using a positive master mold. That is, the fourth resin layer 140 including a recess having a radius of curvature smaller than 0.1 mm is formed by sequentially using a negative master molding die, a positive sub master molding die, and a negative sub sub master molding die. (NPNP method). On the other hand, the first resin layer 110, the second resin layer 110, and the third resin layer 130 that do not include a recess having a radius of curvature smaller than 0.1 mm are a positive master molding die and a negative sub master molding die. Are sequentially used (PNP method). Here, the number of lens portions included in one surface of the wafer lens is not particularly limited. However, from the viewpoint of manufacturing a large number of lens units at a low cost, for example, about 1000 to 20000 is preferable, and 2000 to 10000 is preferable. More preferred is about 3000 to 5000.

The sub master mold, the sub sub master mold, and the wafer lens are all manufactured by forming a resin molding on the substrate. These include: a) a dispensing step of supplying a resin material onto at least one of the substrate and the mold; b) bringing the resin material so as to follow the shape of the molding surface of the mold by bringing the mold and the substrate close to each other. A sandwiching step of sandwiching between the two, c) a solidifying step of solidifying the resin material interposed between the mold and the substrate, and d) a resin molded product bonded to the substrate by separating the mold and the substrate. It is manufactured by a molding process including a mold release process for releasing from the mold.

As described above, the lens portion and the peripheral portion formed on the substrate in the wafer lens are molded products made of a curable resin. On the other hand, the molding part (resin molding having a molding surface) formed on the substrate in the sub master molding die and the sub sub master molding die may be a molding made of a curable resin, or molding of a thermoplastic resin. It may be a thing. As the curable resin, the curable resin described above can be used. On the other hand, examples of thermoplastic resins include alicyclic hydrocarbon resins, acrylic resins, polycarbonate resins, polyester resins, polyether resins, polyamide resins, polyimide resins, and the like. In the solidifying step c), ultraviolet rays may be irradiated when a photocurable resin material is used as the resin material, and infrared rays may be irradiated when a thermosetting resin material is used. Further, when a thermoplastic resin is used as the resin material, the molten resin may be cooled and solidified.

The wafer lens substrate is a transparent substrate such as a glass substrate or a transparent resin substrate. On the other hand, the substrate of the sub master mold and the sub sub master mold may not necessarily be transparent. Examples of these mold substrates include glass substrates, resin substrates, metal substrates, and the like.

The master mold is made of metal, metal glass, glass or the like. A plurality of lens molding surfaces having a shape corresponding to the shape of the lens optical surface of the lens portion is formed on the surface of the master mold by diamond cutting or the like.

In the method of manufacturing the lens unit according to the present embodiment, in the process of manufacturing the wafer lens, the lens portion (the first resin layer 110, the second resin layer 120, and the third resin layer 130) with a small tolerance is small. The sub master mold is manufactured by the direct method (batch molding method), and for the lens portion (fourth resin layer 140) having a large tolerance, the sub master mold is manufactured by the step-and-repeat method. Features.

Specifically, in the manufacturing process of a wafer lens having the first resin layer 110, the second resin layer 120, and the third resin layer 130, a direct method (using a large master mold of a full wafer size) A sub master mold is formed by a batch molding method. Here, the “direct method (collective molding method)” means a method of forming a plurality of resin molded products on one substrate by simultaneously forming all the resin molded products. That is, in the “direct method”, a sub-master mold is manufactured by performing a dispensing process, a clamping process, a solidifying process, and a mold releasing process once using a large master mold having a full wafer size. In this case, the number of lens molding surfaces equal to or more than the number of lens molding surfaces formed on the sub-master molding die is formed on the master molding die. And a lens part is formed using this submaster mold, or the subsubmaster mold produced using this submaster mold.

On the other hand, in the manufacturing process of the wafer lens having the fourth resin layer 140, a sub master mold is formed by a step-and-repeat method using a small master mold. Here, the “step and repeat method” means a method of forming a plurality of resin moldings on one substrate by repeatedly forming one or more resin moldings. That is, in the “step and repeat method”, a sub-master mold is manufactured by repeating the dispensing process, the clamping process, the solidifying process, and the mold releasing process while moving the small master mold (see FIG. 5). In this case, the master molding die is formed with a smaller number (for example, 1 to 100) of lens molding surfaces than the number of lens molding surfaces formed on the sub-master molding die. And a lens part is formed using this submaster mold or a subsubmaster mold produced using this submaster mold.

Hereinafter, with reference to FIGS. 2 to 6, the first step of producing the wafer lens of 1) will be specifically described. In the following description, the sub master mold, the sub sub master mold, and the lens portion are all described using an example of a photocurable resin material. However, when other types of resin materials are used, Needless to say, the resin material may be solidified by a suitable method.

FIG. 2 is a cross-sectional view showing a procedure for forming the first resin layer 110. As described above, the first resin layer 110 is formed by a direct manufacturing method. The first resin layer 110 is formed using a positive master molding die and a negative sub master molding die (PNP format). First, as shown in FIG. 2A, a positive lens molding surface 212a corresponding to the shape of the first lens optical surface 110a ′ and a positive peripheral portion corresponding to the shape of the peripheral surface 110b ′. Using a full wafer size master molding die (second master molding die) 210 having a resin molding surface (fourth molding surface) 212 including a plurality of molding surfaces 212b, the master molding die 210 and the glass substrate 222 are used. The resin material 223 is interposed therebetween, and the resin material 223 is cured by irradiating light from the glass substrate 222 side, whereby a negative-shaped resin molding surface corresponding to the shape of the first resin layer 110 (fifth A sub-master mold 220 having a full wafer size having a (molding surface) 224 is produced. Next, as shown in FIG. 2B, the photocurable resin material 109 is sandwiched between the full-wafer sized submaster mold 220 and the glass substrate (first substrate) 150, and the glass substrate 150 side and / or Alternatively, the first resin layer 110 is formed by irradiating light from the glass substrate 222 side to cure the resin material 109. By the above procedure, as shown in FIG. 2C, a wafer lens 230 having a plurality of first resin layers 110 is obtained. At the time of molding, an appropriate amount of the resin material is individually arranged on each molding surface for the lens corresponding to the lens optical surface on either the molding die or the substrate, and then the molding die and the substrate are brought close to each other. And the resin material is solidified. The same applies to the resin layers 120, 130, and 140 described below. Further, the master mold used for the direct method has a lens mold number equal to or more than the number of lens portions formed on the wafer lens, that is, 1000 to 20000, more preferably 2000 to 10,000, and still more preferably 3000 to 5000. A surface is formed.

FIG. 3 is a cross-sectional view showing a procedure for forming the second resin layer 120. The second resin layer 120 is also formed by a direct manufacturing method. The second resin layer 120 is also formed using a positive master molding die and a negative sub master molding die (PNP format). First, as shown in FIG. 3A, a positive lens molding surface 312a corresponding to the shape of the second lens optical surface 120a ′ and a positive peripheral portion corresponding to the shape of the peripheral surface 120b ′. Using a full wafer size master molding die (second master molding die) 310 having a resin molding surface (fourth molding surface) 312 including a plurality of molding surfaces 312b, the master molding die 310 and the glass substrate 322 are used. The resin material 323 is interposed therebetween, and the resin material 323 is cured by irradiating light from the glass substrate 322 side, whereby a negative-shaped resin molding surface corresponding to the shape of the second resin layer 120 (the fifth A sub-master mold 320 having a full wafer size having a (molding surface) 324 is produced. Next, an alignment mark (not shown) formed on the glass substrate 150 is formed by sub-master mold 320 having a full wafer size and a glass substrate (first substrate) 150 (wafer lens 230) on which the first resin layer 110 is formed. After alignment by reference or the like, as shown in FIG. 3B, a curable resin material 119 is sandwiched between the sub-master mold 320 and the back surface of the glass substrate 150, and the glass substrate 322 and / or the sub-master. The second resin layer 120 is formed by irradiating light from the mold 220 side and curing the resin material 119. By the above procedure, as shown in FIG. 3C, a wafer lens 330 having a plurality of first resin layers 110 on one surface and a plurality of second resin layers 120 on the other surface is obtained.

In the present embodiment, as shown in FIG. 3B, after the first resin layer 110 is formed on one surface of the first substrate 150, before the sub master mold 220 is released, A second resin layer 120 is formed on the other surface of one substrate 150. By doing so, handling of the wafer lens 230 is facilitated. Before forming the first resin layer 110, the second resin layer 120 may be formed.

FIG. 4 is a cross-sectional view showing a procedure for forming the fourth resin layer 140. The fourth resin layer 140 is formed by the NPNP method using a negative master mold. In the present embodiment, the fourth resin layer 140 is formed by a step-and-repeat manufacturing method. First, as shown in FIG. 4A, a negative lens molding surface 412a corresponding to the shape of the fourth lens optical surface 140a ′ and a negative peripheral portion corresponding to the shape of the peripheral surface 140b ′ are used. Using a small master molding die (first master molding die) 410 having a resin molding surface (first molding surface) 412 including a plurality of molding surfaces 412b, the master molding die 410 and the glass substrate 422 By interposing a resin material 423 therebetween and irradiating light from the glass substrate 422 side to cure the resin material 423 on the substrate 422, a positive-shaped resin molding surface corresponding to the shape of the fourth resin layer 140 (first Sub-master mold 420 having a second molding surface 424 is produced. In the example shown in FIG. 4A, as shown in FIG. 5, submaster molding is performed by a “step and repeat method” in which a dispensing process, a clamping process, a solidification process, and a mold release process are repeated using a small master molding die 410. A mold 420 is produced. The master mold is formed with a smaller number (for example, 1 to 200) of lens molding surfaces than the number of lens molding surfaces formed on the sub-master mold. Next, as shown in FIG. 4B, a resin material 433 is interposed between the full-wafer sized sub-master mold 420 and the glass substrate 432, and light is irradiated from the glass substrate 422 side and / or the glass substrate 432 side. By curing the resin material 433, a sub-submaster mold 430 having a negative-shaped resin molding surface (third molding surface) 434 corresponding to the shape of the fourth resin layer 140 is produced. Next, as shown in FIG. 4C, a curable resin material 139 is sandwiched between the sub-submaster mold 430 of full wafer size and the glass substrate (second substrate) 160, and the glass substrate 432 side and / or the glass substrate The fourth resin layer 140 is formed by curing the resin material 139 by irradiating light from the substrate 160 side. Through the above procedure, as shown in FIG. 4D, a wafer lens 440 having a plurality of fourth resin layers 140 is obtained.

Here, the fourth lens optical surface 140a ′ has a larger effective diameter and is closest to the image pickup surface of the image pickup device, etc., so that the tolerance for the lens shape and position compared to other lens optical surfaces is increased. Is relatively large. Therefore, it is appropriate to form the fourth lens optical surface 140a ′ by the NPNP method from the viewpoint of tolerance, and the usage frequency of the master mold 410 is not reduced without degrading the optical performance of the entire lens unit 100. Can be reduced. In the present embodiment, as the master mold 410 for molding the fourth resin layer 140, a mold having a number of lens molding surfaces 412a smaller than the total number of the fourth lens optical surfaces 140 ′ is used. Therefore, it is more advantageous in terms of cost than using a full wafer size master mold. However, if the number of lens molding surfaces 412a of the master mold 410 is too small, the number of step-and-repeat operations using the master mold increases, so in practice, a plurality of lens molding surfaces in a matrix form. It is necessary to use the master mold 410 in which 412a is arranged (for example, 10 × 10), and the master mold is still expensive. Therefore, it is useful to reduce the cost by adopting the NPNP method as in this embodiment.

As described above, in the method of manufacturing the lens unit according to the present embodiment, the lens portion including the lens optical surface with a small tolerance (the first resin layer 110, the second resin layer 120, and the third resin layer described later). 130) is formed by a direct manufacturing method. On the other hand, the lens portion (fourth resin layer 140) including the lens optical surface having a large tolerance is formed by a step-and-repeat manufacturing method.

In the direct manufacturing method, since all the molding surfaces of the sub-master mold are formed simultaneously, the shape error and position error of each molding surface are small. For this reason, a wafer lens having a small shape error and position error can be manufactured. On the other hand, in the direct manufacturing method, a master mold having a large full wafer size must be manufactured, so that the manufacturing cost of the master mold is remarkably increased.

On the other hand, in the step-and-repeat manufacturing method, a plurality of molding surfaces of the sub-master molding die are manufactured in a plurality of times, so that the shape error and position error of each molding surface may increase. For this reason, the shape error and the position error of the wafer lens may be increased to some extent. On the other hand, in the step-and-repeat manufacturing method, since the size of the master mold is small, the manufacturing cost of the master mold is low.

In the lens unit having a plurality of lens optical surfaces arranged in the optical axis direction as in the lens unit of the present embodiment, the function required for each lens optical surface is different, so the shape is different for each lens optical surface. . For example, in an imaging lens unit mounted on an imaging device, in order to prevent the occurrence of shading, in order to reduce the chief ray incident angle of the light beam that forms an image on the imaging surface of the imaging device, the lens optics located closest to the image side It is required to increase the effective diameter of the surface.

Therefore, in the present embodiment, in order to reduce the manufacturing cost without impairing the optical performance of the lens unit, a lens portion (first resin layer 110, second resin layer including a lens optical surface with a small tolerance). 120 and the third resin layer 130) are formed by a direct manufacturing method, and a lens portion (fourth resin layer 140) including a lens optical surface having a large tolerance is formed by a step-and-repeat manufacturing method. To do.

The number of lens molding surfaces 412a in the small master mold 410 is preferably about 0.1 to 10% of the total number of lenses of the wafer lens, for example about 1 to 200, preferably Is about 1 to 100. In particular, when the number of lens molding surfaces 412a is one (that is, a single core), the number of steps and repeats is increased, but lathe processing can be used to manufacture the master mold 410, so that the master mold 410 The processing time, the difficulty of processing, and the production cost are greatly improved. On the other hand, when the number of molding surfaces 412a for the lens is plural, a multi-axis processing machine, a tool rotating shaft, and the like are required to produce the master mold 410, which is a more complicated manufacturing method than the case of a single core. Since the number of step-and-repeats during the production of the sub master mold can be greatly reduced as compared with the case of a single core, the manufacturing time of the wafer lens can be shortened and the master mold can be hardly deteriorated.

Further, a concave portion C4 reflecting a convex portion for controlling the spread of the resin provided in the mold is formed around the lens portion 140a of the fourth resin layer 140. Since the effective diameter of the lens optical surface 140a 'of the fourth resin layer 140 is the largest, the concave portion C4 has a fine structure with a small minimum radius of curvature. Thus, the 4th resin layer 140 has a complicated surface shape. Therefore, it is necessary to process the master mold 412 into a complicated shape corresponding to the complicated surface shape, and it is difficult to produce the master mold 412. However, in the present embodiment, the master molding die 410 used for forming the fourth resin layer 140 is made small so that the master molding die can be easily manufactured.

FIG. 6 is a cross-sectional view showing a procedure for forming the third resin layer 130. The third resin layer 130 is formed by a direct manufacturing method. The third resin layer 130 is formed using a positive master molding die and a negative sub-master molding die (PNP format). First, as shown in FIG. 6A, a positive lens molding surface 512a corresponding to the shape of the third lens optical surface 130a ′ and a positive peripheral portion corresponding to the shape of the peripheral surface 130b ′. Using a full wafer size master mold (second master mold) 510 having a resin mold surface (fourth mold surface) 512 including a plurality of mold surfaces 512b, the master mold 510 and the glass substrate 522 are used. The resin material 523 is interposed therebetween, and the resin material 523 is cured by irradiating light from the glass substrate 522 side, whereby a negative-shaped resin molding surface corresponding to the shape of the third resin layer 130 (the fifth A full wafer size sub-master mold 520 having a molding surface 524 is produced. Next, the sub master mold 520 and the glass substrate (second substrate) 160 (wafer lens 440) on which the fourth resin layer 140 is formed are referred to an alignment mark (not shown) formed on the glass substrate 160. After alignment, as shown in FIG. 6B, a curable resin material 129 is sandwiched between the sub-master mold 520 and the back surface of the glass substrate 160, and light is emitted from the glass substrate 522 side and / or the glass substrate 432 side. The third resin layer 130 is formed by curing the resin material 129 by irradiation. 6C, a wafer lens 530 having a plurality of third resin layers 130 on one surface and a plurality of fourth resin layers 140 on the other surface is obtained.

In the present embodiment, as shown in FIG. 6B, after the fourth resin layer 140 is formed on one surface of the second substrate 160, the second sub-master mold 430 is released before the second sub-master mold 430 is released. A third resin layer 130 is formed on the other surface of the substrate 160. The third resin layer 134 may be formed before forming the fourth resin layer 144.

FIG. 7 is a cross-sectional view for explaining the second step of laminating the wafer lens and other members of 2) above and the third step of dividing the laminate including the wafer lens of 3) above.

First, as shown in FIG. 7A, the wafer lens 330 on which the first resin layer 110 and the second resin layer 120 are formed, the first spacer 170, the third resin layer 130, and the fourth resin layer. The wafer lens 530 formed with 140 and the second spacer 180 are laminated in this order and fixed to obtain a laminated body. Usually, an adhesive layer (not shown) is formed between the constituent members, and these constituent members are bonded and fixed to each other. Note that in obtaining the stacked body, alignment may be performed by referring to alignment marks (not shown) formed on the first substrate 150 and the second substrate 160. A fixing sheet 610 having an adhesive layer is attached to the lower surface of the second spacer 180 of the laminate thus obtained.

Next, as shown in FIG. 7B and FIG. 7C, the laminated body is divided (cut) for each lens unit 100 using a cutting blade 620 or the like. At this time, from the viewpoint of easy handling, it is preferable to completely cut only the lens unit 100 without completely cutting the fixing sheet 610. By the above procedure, as shown in FIG. 7D, a plurality of lens units 100 fixed on the fixing sheet 610 can be manufactured. Thereafter, the lens unit 100 shown in FIG. 1 can be obtained by removing the fixing sheet 610.

In the manufacturing method of the lens unit of the present embodiment, the resin layer (fourth resin layer 140) including a recess having a radius of curvature smaller than 0.1 mm includes a negative master mold, a positive submaster mold, and a negative mold. It is formed using a sub-submaster mold of the mold (NPNP method). On the other hand, the resin layer (the first resin layer 110, the second resin layer 120, and the third resin layer 130) that does not include a recess having a radius of curvature smaller than 0.1 mm is formed of a positive master mold and a negative mold. It is formed using a sub master mold (PNP method). The reason why the manufacturing procedure is changed depending on the minimum radius of curvature of the concave portion of the resin layer will be described with reference to FIG.

The minimum value of the radius of curvature of the tip of a tool currently on the market is about 0.03 mm. Therefore, a recess having a curvature radius smaller than 0.03 mm, which is the minimum curvature radius of the tip portion of the commercial tool, cannot be formed in the master mold. Further, as described above, when a master mold is manufactured, a plurality of lens molding surfaces are repeatedly formed on one mold, so that the occurrence of processing defects due to tool wear becomes a problem. This problem is particularly problematic when using a tool having a small radius of curvature at the tip. Therefore, in practical use, it is preferable to use a tool having a radius of curvature of 0.1 mm or more. As a result, the minimum radius of curvature of the concave portion that can be formed in the master mold is at most 0.1 mm.

FIG. 8A shows that when the minimum curvature radius R2 of the recess to be processed into the positive master mold 720P is equal to or larger than the curvature radius R1 of the tip of the processing tool 710 (R2 ≧ R1), the master mold 720P is changed. It shows how it is processed. In this case, as shown in the figure, by processing the master mold 720P so that the tool 710 enters the recess, the recess having the curvature radius R2 can be appropriately formed.

FIG. 8B is a schematic diagram showing how a negative master molding die 720N for molding a resin layer including a recess is produced using a tool 710. FIG. As shown in this figure, when forming a molding surface corresponding to a resin layer having a recess in a negative master molding die 720N, a convex portion having a shape obtained by inverting the recess formed in the resin layer is master-molded. The mold 720N is formed. And when forming a convex part in this way, even if it uses the tool 710 with the front-end | tip part which has larger curvature radius R1 than the minimum curvature radius R2 of a recessed part as shown in this figure, it is a master mold. Appropriate processing can be performed on 720N.

FIG. 8C shows the processing of the master mold 720P in the case where the minimum curvature radius R2 of the recess (shown by a broken line) to be processed into the positive master mold 720P is smaller than the curvature radius R1 of the tip portion of the processing tool 710. The state of is shown. As shown in this figure, the radius of curvature R1 of the tool 710 is larger than the minimum radius of curvature R2 of the recess to be formed, and the tool 710 interferes with the master mold 720P. Can not.

In this way, the minimum radius of curvature R2 of the recess formed in the master mold is greater than or equal to the radius of curvature R1 of the machining tool, or a convex is formed on the master mold, or the radius of curvature of the tool tip is formed on the master mold. If there is no need to form a recess having a radius of curvature smaller than R1, it is possible to perform processing appropriately. Therefore, in the manufacturing method of the lens unit of the present embodiment, the resin layer (fourth resin layer 140) including the concave portion that has the minimum curvature radius R2 smaller than 0.1 mm and falls below the curvature radius R1 of the processing tool is obtained. The negative master molding die is selected, and a negative master molding die, a positive sub master molding die and a negative sub sub master molding die are used (NPNP method). On the other hand, from the viewpoint of improving the accuracy of the lens portion, it is preferable to use a positive master molding die with a small number of intermediate molding dies, so that the tolerance for the shape is small and the minimum radius of curvature R2 is For the resin layer (the first resin layer 110, the second resin layer 120, and the third resin layer 130) not including a recess of 0.1 mm or less, a positive master mold and a negative sub master mold are used. (PNP method).

As described above, in the method of manufacturing the lens unit according to the present embodiment, all lens optical surfaces are molded using the resin intermediate mold, so that the cost can be increased while maintaining the necessary optical performance. Can be suppressed. Whether to use a positive master mold or a negative master mold depending on the shape of the resin layer including the lens part to be finally obtained in the process of manufacturing the wafer lens. Therefore, even if a tool having a tip R of more than 0.1 mm is used, a lens unit in which each lens optical surface is formed with high accuracy can be manufactured. In particular, since the fourth resin layer is molded by the NPNP method, the number of intervening intermediate molds is greater than that of other resin layers, but it can be said that the optical performance is hardly deteriorated because of a large tolerance. Also, in the process of manufacturing the wafer lens, the manufacturing method of the sub-master mold is varied according to the accuracy (allowable error) required for the lens part, so that the manufacturing cost is not impaired without impairing the optical performance of the lens unit. Can be reduced.

In this embodiment, an example in which a lens unit is manufactured by combining two wafer lenses has been described, but the number of wafer lenses is not particularly limited. For example, a lens unit may be manufactured using one wafer lens (see the third embodiment), or a lens unit may be manufactured using three or more wafer lenses (second embodiment). See form).

In this embodiment, an example in which a lens unit is manufactured using a wafer lens in which lens portions are formed on both surfaces of the substrate has been described. However, a wafer lens in which a lens portion is formed only on one surface of the substrate is described. You may use (refer 2nd Embodiment).

In the present embodiment, the first to third resin layers are formed by a “direct method” in which a dispensing process, a sandwiching process, a solidifying process, and a releasing process are performed once using a large master mold. For forming the fourth resin layer by the “step and repeat method” in which the dispensing process, the clamping process, the solidifying process and the releasing process are repeated using a small master mold. A sub-master mold as an intermediate mold was produced. The fourth resin layer is formed by the NPNP method using a sub-master molding die formed by the step-and-repeat method. However, since the tolerance of the fourth resin layer is large, the deterioration of the optical performance is suppressed. However, cost reduction can be realized. In particular, for the fourth resin layer, the frequency of use of a small master mold is increased to perform step-and-repeat. However, since the molding is performed by the NPNP method using the sub-sub master mold, The frequency of use can be lowered. However, whether the sub-master mold for each resin layer is manufactured by the direct method or the step-and-repeat method may be determined in consideration of the optical performance and the manufacturing cost. For example, if the number of lens portions per wafer lens is not so large, a sub-master mold for the fourth resin layer may be produced by the direct method, and if the optical performance is acceptable. The sub-master mold for the third resin layer may be produced by a step-and-repeat method.

In addition, for example, the fourth resin layer may be formed by the PNP method if a slight decrease in optical performance is avoided, or the first resin layer to the third resin layer may be formed if the optical performance permits. Any of these may be formed by the NPNP method.

The NPNP format using the sub-sub master mold is superior in terms of reducing manufacturing costs because a larger number of intermediate molds (sub-sub master molds) can be produced from one master mold. On the other hand, since the number of times of transfer from the master mold to the wafer lens is 3, the shape error and the position error are likely to increase. On the other hand, the PNP format that does not use the sub-sub master mold is suitable for manufacturing a lens portion having a small tolerance because the number of transfers from the master mold to the wafer lens is two. Therefore, by appropriately combining these, an increase in manufacturing cost can be avoided without impairing optical performance.

As shown in the present embodiment, the lens optical surface (fourth resin layer) located closest to the imaging surface has a large tolerance, so that the NPNP format using the sub-submaster mold is used from the viewpoint of reducing the manufacturing cost. Is preferably formed.

(Second Embodiment)
In the first embodiment, an example of manufacturing a lens unit having a two-layer structure is shown. However, in the second embodiment, an example of manufacturing a lens unit having a three-layer structure is shown. The material of each constituent member is the same as that of each constituent member of the first embodiment, and detailed description thereof is omitted.

FIG. 9 is a cross-sectional view showing the lens unit of the second embodiment. As shown in this figure, the lens unit 800 includes a first resin layer 805 including a lens portion, a second resin layer 810 including a lens portion, a third resin layer 815 including a lens portion, and a lens portion. Fourth resin layer 820, fifth resin layer 825 including a lens portion, first substrate 830, second substrate 835, third substrate 840, first spacer 845, second spacer 850 and third The spacer 855 is provided.

The first resin layer 805 is formed on one surface of the first substrate 830. The second resin layer 810 is formed on one surface of the second substrate 835, and the third resin layer 815 is formed on the other surface of the second substrate 835. Similarly, the fourth resin layer 820 is formed on one surface of the third substrate 840, and the fifth resin layer 825 is formed on the other surface of the third substrate 840. . A first spacer 845 is disposed between the first substrate 830 and the second substrate 835, and the first substrate 830 and the second resin layer 810 facing each other are separated from each other. Similarly, a second spacer 850 is disposed between the second substrate 835 and the third substrate 840, and the third resin layer 815 and the fourth resin layer 820 facing each other are separated from each other. ing. The third spacer 855 is disposed on the surface of the third substrate 840 where the fifth resin layer 825 is formed. The third spacer 855 controls the interval between the fifth resin layer 825 and an imaging surface of an imaging element (not shown).

The first resin layer 805, the second resin layer 810, and the third resin layer 815 do not include a recess having a radius of curvature smaller than 0.1 mm, and a positive master molding die and a negative sub master molding die are used. It is formed using (PNP method). Further, the sub-master molds corresponding to the first resin layer 805, the second resin layer 810, and the third resin layer 815 are manufactured by a direct method.

The fourth resin layer 820 and the fifth resin layer 825 include a concave portion having a radius of curvature smaller than 0.1 mm, and are provided with a negative master molding die, a positive sub master molding die, and a negative sub sub master molding die. It is formed using (NPNP method). In addition, the sub master mold corresponding to the fourth resin layer 820 and the fifth resin layer 825 is manufactured by a step-and-repeat method.

In the method of manufacturing the lens unit 800 of the present embodiment, the steps of laminating wafer lenses and the like and dividing (cutting) the laminated body are the same as the procedures described in the first embodiment.

As described above, the lens optical surface manufactured by the first wafer lens manufacturing method using the sub-submaster mold is not limited to the lens optical surface positioned closest to the image side, and may be another lens optical surface. . Further, as in the present embodiment, a plurality of lens optical surfaces may be manufactured by a first wafer lens manufacturing method using a sub-submaster mold. Further, as in the present embodiment, the lens optical surface manufactured by the step-and-repeat manufacturing method is not limited to the lens optical surface located closest to the image side, and may be another lens optical surface. Further, as in the present embodiment, a plurality of lens optical surfaces may be manufactured by a step-and-repeat manufacturing method. Further, it is not always necessary that all wafer lenses have lens portions on both sides as in the first embodiment, and a form in which wafer lenses having lens portions on only one side are laminated as in this embodiment. It may be.

The manufacturing method of the lens unit of the present embodiment can obtain the same effects as those of the first embodiment.

(Third embodiment)
In the first embodiment, an example of manufacturing a lens unit having a two-layer structure is shown. However, in the third embodiment, an example of manufacturing a lens unit having a single-layer structure is shown. The material of each constituent member is the same as that of each constituent member of the first embodiment, and detailed description thereof is omitted.

10A is a cross-sectional view of the lens unit according to the third embodiment (cross-sectional view taken along line AA shown in FIG. 10B), and FIG. 10B is a bottom view of the lens unit according to the third embodiment. is there. As shown in these drawings, the lens unit 900 includes a first resin layer 910 including a first lens portion 910a and a peripheral portion 910b thereof, and a second resin including a second lens portion 920a and a leg portion 920b. A resin layer 920 and a first substrate 930 are included.

The first resin layer 910 is formed on one surface of the first substrate 930, and the second resin layer 920 is formed on the other surface of the first substrate 930. The second resin layer 920 includes a second lens portion 920a and leg portions 920b protruding along the optical axis direction of the second lens portion 920a. The leg portion 920b functions as a spacer and controls the interval between the second resin layer 920 (second lens portion 920a) and the imaging surface of an imaging element (not shown). The leg portion 920b prevents the second lens portion 920a from coming into contact with another member and being damaged in various steps after forming the second lens portion 920a, such as each step in manufacturing the imaging lens module. It also functions as a protective member. In addition, in this embodiment, although the leg part 920b is cyclic | annular, it does not necessarily need to be continuous and may be formed discretely.

As shown in FIG. 10, the first resin layer 910 includes a recess C1 similar to the first resin layer 110 of the first embodiment between the first lens portion 910a and the peripheral portion 910b. However, it does not include a recess having a curvature radius smaller than 0.1 mm, and is formed using a positive master molding die and a negative sub master molding die (PNP method). Further, the sub master mold corresponding to the first resin layer 910 is manufactured by a direct method.

The second resin layer 920 (the second lens portion 920a and the leg portion 920b) is integrally molded. The second resin layer 920 includes a concave portion C2 having a radius of curvature smaller than 0.1 mm at a connection portion between the second lens portion 920a and the leg portion 920b, and is a negative master molding die or a positive sub master molding die. And a negative type sub-submaster mold (NPNP method). Further, the sub master mold corresponding to the second resin layer 920 is manufactured by a step-and-repeat method. That is, the second resin layer 920 has a steep concave portion C2 around the lens portion 920a. However, since the second resin layer 920 is formed by the NPNP method, the portion of the master mold corresponding to the concave portion is a convex portion. Processing with a tool is possible in the same manner as described in the first embodiment and the second embodiment.

The manufacturing method of the lens unit 900 of the present embodiment does not include a step of laminating wafer lenses or the like, but includes a step of dividing (cutting) the wafer lens. The process of dividing the wafer lens is the same as the procedure described in the first embodiment.

The manufacturing method of the lens unit of the present embodiment can obtain the same effects as those of the first embodiment.

This application claims priority based on Japanese Patent Application No. 2011-266782 filed on December 6, 2011 and Japanese Patent Application No. 2011-266783 filed on December 6, 2011. The contents described in the application specification and the drawings are all incorporated herein by reference.

The method for manufacturing a lens unit of the present invention is useful, for example, in manufacturing an imaging lens unit.

100, 800, 900 Lens unit 109, 119, 129, 139 Photocurable resin material 110, 805, 910 First resin layer 110 ′ Surface of first resin layer 110a, 910a First lens portion 110a ′ first Lens optical surfaces 110b, 910b Peripheral part 110b 'of the first lens part Surfaces 120,810,920 of the first lens part 120', surface of the second resin layer 120a, 920a 2nd lens part 120a '2nd lens optical surface 120b Peripheral part of 2nd lens part 120b' Surface of peripheral part of 2nd lens part 130,815 3rd resin layer 130 'Surface of 3rd resin layer 130a Third lens part 130a 'Third lens optical surface 130b Third lens part peripheral part 130b' Third lens part peripheral part 140,820 Fourth resin layer 140 ′ Fourth resin layer surface 140a Fourth lens portion 140a ′ Fourth lens optical surface 140b Fourth lens portion peripheral portion 140b ′ Fourth lens portion peripheral portion surface 150 , 830, 930 First substrate 160, 835 Second substrate 170, 845 First spacer 180, 850 Second spacer 210, 310, 410, 510 Master mold 212, 312, 412, 512 Master mold Resin molding surface 212a, 312a, 412a, 512a Master molding lens molding surface 212b, 312b, 412b, 512b Master molding die peripheral molding surface 220, 320, 420, 520 Submaster molding die 222, 322, 422 , 522 Sub-master mold substrate 223, 323, 423, 433, 523 Resin Materials 224, 324, 424, 524 Sub-master molding die resin molding surfaces 224a, 324a, 424a, 524a Sub-master molding lens molding surfaces 224b, 324b, 424b, 524b Sub-master molding peripheral molding surfaces 230 Wafer lens having first lens portion 330 Wafer lens having first lens portion and second lens portion 430 Sub-sub master mold 432 Sub-sub master mold substrate 434 Sub-sub master mold resin molding surface 434a Sub-sub master molding Mold surface for mold 434b Mold surface for peripheral portion of sub-sub master mold 440 Wafer lens having fourth lens portion 530 Wafer lens having third lens portion and fourth lens portion 610 Fixing sheet 620 Cutting blade 710 Tool 7 0P positive master mold 720N negative of the master mold 825 fifth resin layer 840 third substrate 855 third spacer 920b legs C1, C2, C3, C4 recess

Claims (20)

A method for manufacturing a lens unit having a plurality of lens optical surfaces, including a first lens optical surface and a second lens optical surface arranged side by side in the optical axis direction,
The first lens optical surface is:
By performing molding using a first master molding die having a first molding surface including a plurality of negative lens molding surfaces corresponding to the shape of the first lens optical surface and a resin material, the first Producing a first sub-master mold having a second molding surface including a plurality of positive lens molding surfaces corresponding to the shape of the lens optical surface;
A sub-sub having a third molding surface including a plurality of negative lens molding surfaces corresponding to the shape of the first lens optical surface by molding using the first sub-master molding die and the resin material. Producing a master mold; and
Forming a first resin layer having a first surface including a plurality of first lens optical surfaces by molding using the sub-submaster mold and the curable resin material;
Including a first wafer lens manufacturing method,
The second lens optical surface is:
By performing molding using a second master mold having a fourth molding surface including a plurality of positive lens molding surfaces corresponding to the shape of the second lens optical surface and a resin material, the second Producing a second sub-master mold having a plurality of fifth molding surfaces including a plurality of negative lens molding surfaces corresponding to the shape of the lens optical surface;
Forming a second resin layer having a second surface including a plurality of the second lens optical surfaces by molding using the second sub-master mold and the curable resin material;
Formed by a second wafer lens manufacturing method,
A manufacturing method of a lens unit. The first surface includes a recess having a radius of curvature smaller than a radius of curvature of a tip portion of a tool for producing the first master mold.
The second surface does not include a recess having a radius of curvature smaller than the radius of curvature of the tip of a tool for producing the second master mold.
The manufacturing method of the lens unit of Claim 1. The first surface includes a recess having a radius of curvature of less than 0.1 mm;
The second surface does not include a recess having a radius of curvature of less than 0.1 mm;
The manufacturing method of the lens unit of Claim 1. The method for manufacturing a lens unit according to claim 3, wherein the first surface includes a recess having a radius of curvature smaller than 0.03 mm. In the manufacturing method of the first wafer lens, after individually disposing the curable resin material on at least the plurality of lens molding surfaces of the third molding surface of the sub-submaster molding die, The method for producing a lens unit according to any one of claims 1 to 4, wherein molding is performed by curing a curable resin material. The first sub-master mold is a step-and-step that forms a plurality of resin moldings on one substrate by repeatedly forming one or more resin moldings using the first master molding die. Produced by repeat method,
The second sub-master mold is produced by a direct method in which a plurality of resin molded products are formed on one substrate by simultaneously forming all the resin molded products using the second master mold. The
The method for manufacturing a lens unit according to any one of claims 1 to 5. A method of manufacturing a lens unit having a plurality of lens optical surfaces including a first lens optical surface and a second lens optical surface arranged side by side in the optical axis direction,
The first lens optical surface and the second lens optical surface are:
Sub master mold having a plurality of lens molding surfaces corresponding to the shape of the lens optical surface by molding using a master molding die having a lens molding surface corresponding to the shape of the lens optical surface and a resin material A step of producing
A wafer having a plurality of lens portions including the lens optical surface by molding using the sub-master mold or the sub-sub-master mold produced using the sub-master mold and a curable resin material. Producing a lens;
Including a wafer lens manufacturing method,
The first sub-master mold corresponding to the first lens optical surface is a first master mold having one or more lens molding surfaces having a shape corresponding to the shape of the first lens optical surface. Using one or two or more resin moldings to form a plurality of resin moldings on a single substrate, thereby producing a step-and-repeat method,
The second sub-master mold corresponding to the second lens optical surface is a second master mold having a plurality of lens molding surfaces having a shape corresponding to the shape of the second lens optical surface. Produced by the direct method of forming a plurality of resin moldings on one substrate by forming all the resin moldings simultaneously.
A manufacturing method of a lens unit. The method of manufacturing a lens unit according to claim 7, wherein the first lens optical surface is formed by molding using the sub-submaster mold and the curable resin material. The sub-sub master mold is formed by interposing a resin material between the first sub-master mold and the substrate, solidifying the resin material, and then releasing the first sub-master mold. The manufacturing method of the lens unit of Claim 8 produced. 10. The number of lens molding surfaces of the first master molding die is 1/100 to 1/10 of the number of lens molding surfaces of the second master molding die. The manufacturing method of the lens unit of description. The method for manufacturing a lens unit according to any one of claims 1 to 10, wherein the first lens optical surface has a larger tolerance for shape and / or position than the second lens optical surface. . The lens unit manufacturing method according to any one of claims 1 to 11, wherein the lens optical surface located closest to the image side among the plurality of lens optical surfaces is the first lens optical surface. The method of manufacturing a lens unit according to any one of claims 1 to 12, wherein an effective diameter of the first lens optical surface is the largest among the plurality of lens optical surfaces. Forming a wafer lens by forming a plurality of the first lens optical surfaces on one surface of the substrate and forming a plurality of the second lens optical surfaces on the other surface of the substrate; The method for manufacturing a lens unit according to any one of claims 13 to 14. 15. The method of manufacturing a lens unit according to claim 14, further comprising a step of cutting the wafer lens for each pair of the first and second lens optical surfaces. A first wafer lens in which the first lens optical surface is formed on a first substrate, and a second wafer lens in which the second lens optical surface is formed on a second substrate, a spacer The method for manufacturing a lens unit according to any one of claims 1 to 15, further comprising a step of stacking the layers to form a stacked body. The method further includes a step of cutting the laminated body for each of the corresponding first and second lens optical surfaces of the first wafer lens and the first and second lens optical surfaces of the second wafer lens. Item 17. A method for manufacturing a lens unit according to Item 16. A lens unit manufactured by the method for manufacturing a lens unit according to any one of claims 1 to 17. 19. A concave portion derived from the sub-master mold for molding the first lens optical surface or a convex portion formed on the sub-sub-master mold in the periphery of the first lens optical surface. The lens unit described in 1. A leg projecting in the direction of the lens optical axis around the first lens optical surface;
A concave portion between the leg portion and the first lens optical surface;
The lens unit according to claim 18 or 19.

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