Structure manufacturing method and structure

Abstract

Provided are: a structure manufacturing method with which a fine textured structure is easily formed only on a desired portion of a substrate without a curable resin protruding from the periphery thereof; and said structure. The structure manufacturing method comprises: a modification step for forming a non-modified portion 10 and a modified portion 20 on a surface of a substrate 101; an application step for applying a curable resin to the surface; a structure formation step for forming a fine textured structure in the curable resin applied to the substrate 101; a curing step for curing the curable resin; and a removal step for removing a cured product of the curable resin applied to the non-modified portion 10.

Description

Method for manufacturing a structure and the structure

[0001] The present disclosure relates to a method for manufacturing a structure and the structure.

[0002] Plastic lenses such as COP (cycloolefin polymers) and COC (cycloolefin copolymers) are widely used in lenses for VR (virtual reality), AR (augmented reality), camera modules, etc. It is known that high transmittance can be ensured by imparting a microstructure such as a moth-eye structure to the surface of a plastic lens such as a COP or COC.

[0003] A known method for forming a fine structure is the nanoimprint method, in which a curable resin applied to the surface of a substrate such as a plastic lens is pressed with a mold engraved with a fine pattern to transfer the fine pattern to the curable resin.

[0004] For example, Patent Document 1 discloses a method in which a transfer object, which is a substrate on which a molding material (photocurable resin) is provided, is placed on a stage, and a mold held via a spring part is pressed against the transfer object using a roller, thereby transferring the fine uneven structure formed on the mold to the transfer object.

[0005] Patent Document 2 discloses a method for transferring a fine relief structure to a photocurable resin on the surface of a substrate. Specifically, this method includes the steps of first applying a photocurable resin onto the substrate so that the photocurable resin covers the surface of the substrate and extends beyond the periphery of the substrate, then pre-curing only the photocurable resin in the extended portion, and then pressing a mold on which a fine relief structure has been formed onto the photocurable resin on the surface of the substrate.

[0006] JP 2017-5085 A JP 2016-213423 A

[0007] However, with the conventional technology described in Patent Document 1, when pressing the material to be molded (photocurable resin) against the substrate using a roller, the material to be molded (photocurable resin) sometimes spills over into areas on the substrate where the fine relief structure is not intended to be formed. If the photocurable resin is uncured and liquid at the edge of the lens corresponding to the spilled area, the edge or the area inside the edge where the fine relief structure is to be formed may be contaminated, potentially impairing the properties of the optical element. Furthermore, with the conventional technology described in Patent Document 2, the addition of a pre-curing step increases the complexity of the process.

[0008] In conventional methods, nanoimprinting on 3D lenses or individual substrates has the problem that if the curable resin that protrudes beyond the area where the fine unevenness structure is intended to be formed hardens, the edge shape of the lens becomes larger than the specified design value, making it difficult to function as an optical element. Therefore, there has been a need for a method for manufacturing a structure that can easily form a fine unevenness structure only in the desired area of ​​the substrate without the curable resin protruding to the periphery.

[0009] The present invention aims to provide a method for easily manufacturing a structure in which a fine uneven structure is formed only in desired areas of a substrate without the curable resin spilling out onto the surrounding areas, and to provide the structure itself.

[0010] That is, the gist of the present invention is as follows: (1) A method for manufacturing a structure, including a modifying step of forming an unmodified portion and a modified portion on the surface of a substrate, a coating step of coating the surface with a curable resin, a structure forming step of forming a fine uneven structure in the curable resin coated on the substrate, a curing step of curing the curable resin, and a removal step of removing the cured product of the curable resin coated on the unmodified portion.

[0011] (2) A method for manufacturing a structure described in (1) above, wherein the modification step includes a step of covering a first portion of the surface with a mask, a step of modifying a second portion of the surface that is not covered by the mask as the modified portion, and a step of removing the mask.

[0012] (3) The method for manufacturing a structure according to (1) or (2) above, wherein the structure forming step is carried out using a mold having an inverted shape of the fine concave-convex structure.

[0013] (4) A method for manufacturing a structure described in any one of (1) to (3) above, wherein the water droplet contact angle of the modified portion formed in the modification process is smaller by 40 degrees or more than the water droplet contact angle of the unmodified portion.

[0014] (5) The method for producing a structure according to (2) above, wherein the modifying step is carried out by a surface modification treatment selected from the group consisting of an excimer treatment, a silane coupling treatment, and a primer treatment.

[0015] (6) A method for manufacturing a structure described in any of (1) to (5) above, wherein the modification step includes a material application step of forming the unmodified portion using a first material in a first portion of the surface, and forming the modified portion using a second material different from the first material in a second portion of the surface different from the first portion.

[0016] (7) The method for producing a structure according to any one of (1) to (6) above, wherein the substrate is formed from a cycloolefin resin.

[0017] (8) A structure comprising a substrate having an unmodified portion and a modified portion on its surface, and a microrelief structure layer made of a curable resin disposed only on the modified portion of the substrate.

[0018] (9) The structure according to (8) above, wherein the water droplet contact angle of the modified portion is smaller than the water droplet contact angle of the unmodified portion by 40 degrees or more.

[0019] (10) A structure described in (8) or (9) above, wherein the non-modified portion is formed on a first portion of the surface using a first material, and the modified portion is formed on a second portion of the surface using a second material different from the first material.

[0020] (11) The structure according to any one of (8) to (10) above, wherein the substrate is formed from a cycloolefin resin.

[0021] According to the present invention, it is possible to easily provide a method for manufacturing a structure in which a fine uneven structure is formed only in desired areas of a substrate without the curable resin spilling out to the surrounding areas, and to provide the structure.

[0022] FIG. 1 is a schematic diagram showing one step in a method for manufacturing a structure according to one embodiment of the present invention. FIG. 2 is a schematic diagram showing one step in a method for manufacturing a structure according to one embodiment of the present invention. FIG. 3 is a schematic diagram showing one step in a method for manufacturing a structure according to one embodiment of the present invention. FIG. 4 is a schematic diagram showing one step in a method for manufacturing a structure according to one embodiment of the present invention. FIG. 5 is a schematic diagram showing one step in a method for manufacturing a structure according to one embodiment of the present invention, and is a schematic cross-sectional view showing a structure according to one embodiment of the present invention.

[0023] The present invention will be described in detail below based on embodiments.

[0024] (Method for manufacturing a structure) The method for manufacturing a structure of the present invention is characterized by comprising a modification step of forming a non-modified portion and a modified portion on the surface of a substrate, a coating step of coating a curable resin on the surface, a structure formation step of forming a fine uneven structure in the curable resin coated on the substrate, a curing step of curing the curable resin, and a removal step of removing the cured product of the curable resin coated on the non-modified portion.

[0025] As used herein, the term "unmodified portion" refers to a portion of the substrate surface that has not been subjected to a surface modification treatment, or a portion of the substrate surface that is formed from a first material. As used herein, the term "modified portion" refers to a portion of the substrate surface that has been subjected to a surface modification treatment, or a portion of the substrate surface that is formed from a second material that is different from the first material. In the relationship between the modified portion and the unmodified portion in this specification, the water droplet contact angle of the modified portion is smaller than the water droplet contact angle of the unmodified portion by, for example, 40 degrees or more. As used herein, the surface modification treatment refers to a treatment selected from the group consisting of an excimer treatment, a silane coupling treatment, and a primer treatment.

[0026] In this specification, the water droplet contact angle was measured by the θ / 2 method based on JIS R3257 "Test method for wettability of substrate glass surfaces." Specifically, the boundary line between the water droplet and the water droplet-receiving contact body, and the angle formed by the line connecting one of the contact points between the water droplet and the water droplet-receiving contact body and the apex of the water droplet were measured using an optical reading device, and the obtained value was doubled.

[0027] In this specification, excimer treatment means irradiating a substrate with light (excimer light) having a wavelength of 150 nm to 200 nm. In this specification, silane coupling treatment means dripping or spraying a silane coupling agent onto a substrate. In this specification, primer treatment means applying a silane coupling agent onto a substrate.

[0028] A method for manufacturing a structure according to one embodiment of the present invention (hereinafter, sometimes referred to as the "manufacturing method of this embodiment") will be described below with reference to FIGS. 1A to 1G.

[0029] <Modification Step> The modification step is a step of forming a non-modified portion 10 and a modified portion 20 on the surface of the substrate 101. The modification step preferably includes a mask covering step, a modification step, and a mask removal step. This method allows the modified portion 20 to be formed in any portion of the surface of the substrate 101, and the microrelief structure layer 102 made of a curable resin to be disposed only on the modified portion 20 of the substrate 101. <<Mask Covering Step>> The mask covering step is a step of covering, with a mask, portions of the surface of the substrate 101 where the formation of the microrelief structure layer 102 is not intended. In the manufacturing method of this embodiment, as shown in FIG. 1A , a first portion 10a on the surface of the substrate 101 is covered with a mask 150. The first portion 10a corresponds to the portion where the formation of the microrelief structure layer 102 is not intended. Here, the portion of the substrate 101 not covered with the mask 150 is referred to as a second portion 20a. The second portion 20a corresponds to the portion where the microrelief structure layer 102 is intended to be formed. <<Modifying Step>> The modifying step is a step of performing a surface modification treatment on the second portion 20a not covered by the mask on the surface of the substrate 101, as a modified portion, by a treatment selected from the group consisting of an excimer treatment, a silane coupling treatment, and a primer treatment. In the manufacturing method of this embodiment, as shown in FIG. 1B , excimer light is irradiated onto the upper surface of the substrate 101. At this time, because the excimer light does not pass through the mask 150, the first portion 10a on the surface of the substrate 101 covered by the mask 150 is not modified and corresponds to the unmodified portion 10. Only the second portion 20a not covered by the mask 150 is subjected to the surface modification treatment, and the second portion 20a corresponds to the modified portion 20. <<Mask Removing Step>> The mask 150 removing step is a step of removing the mask 150 that covered the first portion 10a on the surface of the substrate 101. After removing the mask 150, the substrate 101 is in the state shown in Fig. 1C. In Fig. 1C, the modified portion of the surface is designated as a modified portion 20, and the unmodified portion is designated as a non-modified portion 10, as in Fig. 1B.

[0030] In the modification step, the surface of the substrate 101 is modified by excimer treatment, but the modification step is not limited to this. Instead of or in addition to the surface modification of the substrate 101, a non-modified portion 10 made of a first material may be formed in a first portion 10a of the surface of the substrate 101, and a modified portion 20 made of a second material different from the first material may be formed in a second portion 20a.

[0031] The water droplet contact angle of the modified section 20 is preferably 40 degrees or more smaller than the water droplet contact angle of the unmodified section 10, more preferably 50 degrees or more smaller, and even more preferably 60 degrees or more smaller. By performing a surface modification treatment so that the water droplet contact angle of the modified section 20 is 40 degrees or more smaller than the water droplet contact angle of the unmodified section 10, the wettability of the curable resin described below to the modified section 20 is improved.

[0032] <Coating Step> The coating step is a step of coating (potting) a curable resin onto the surface of the substrate 101 that has undergone the modification step. In the manufacturing method of this embodiment, as shown in FIG. 1D , a UV (Ultra-Violet) curable resin 160 is coated onto the substrate 101. The UV curable resin 160 is not particularly limited, but examples thereof include a UV curable acrylic resin and a UV curable epoxy resin. Furthermore, various additives such as a curing initiator may be added to the UV curable resin 160 as needed.

[0033] <Structure Forming Process> The structure forming process is a process of forming a microrelief structure in the UV-curable resin 160 applied to the substrate 101 in the application process. Specifically, a mold on which a microrelief structure has been formed is placed on the substrate 101 via the UV-curable resin 160, and the UV-curable resin 160 is pressed against the mold. The microrelief structure formed on the mold preferably has an inverted shape of the microrelief structure to be formed on the substrate 101. The mold on which the microrelief structure has been formed is not particularly limited, and examples thereof include a thin film optical element on a carrier film or a mold. Furthermore, examples of the microrelief structure are not particularly limited, and examples thereof include a moth-eye structure, a microlens array structure, a diffractive structure, and the like. In the manufacturing method of this embodiment, as shown in FIG. 1E, a film mold 250 on which a microrelief structure has been formed is placed on the substrate 101 via the UV-curable resin 160. Next, the UV-curable resin 160 is pressed against the film mold 250. Here, by adjusting the pressure and time during pressing, it is possible to adjust the thickness of the fine concave-convex structure layer 102 that is finally obtained, which will be described later.

[0034] <Curing Process> The curing process is a process of curing the curable resin pressed onto the mold on which the microrelief structure was formed in the structure forming process. The method for curing the curable resin is preferably selected from UV curing, heat curing, or room temperature chemical reaction depending on the properties of the curable resin. In the manufacturing method of this embodiment, UV curable resin 160 is cured by UV irradiation as shown in FIG. 1E. After the UV curable resin 160 has cured, the film mold 250 on which the microrelief structure was formed is peeled off, resulting in a microrelief structure layer 102 being formed on the substrate 101 as shown in FIG. 1F.

[0035] <Removing Step> The removing step is a step of removing a cured product of the curable resin applied to the non-modified portion 10. For example, the removing step is a step of removing the microrelief structure layer 102 on the non-modified portion 10 from the microrelief structure layer 102 formed on the substrate 101. In the manufacturing method of this embodiment, the microrelief structure layer 102 formed on the non-modified portion 10 is removed to obtain the structure 100 shown in FIG. 1G. Due to the surface modification treatment in the modifying step, the microrelief structure layer 102 on the modified portion 20 is more difficult to peel off than the microrelief structure layer 102 on the non-modified portion 10, so it is possible to peel off only the microrelief structure layer 102 on the non-modified portion 10.

[0036] (Structure) The structure 100 of the present invention is characterized in that it includes a substrate 101 having an unmodified portion 10 and a modified portion 20 on its surface, and a microrelief structure layer 102 made of a UV-curable resin 160 is disposed only on the modified portion 20 of the substrate 101. In the present invention, "disposed only on the modified portion" does not include a case in which the UV-curable resin 160 unintentionally protrudes into a portion other than the modified portion 20 (specifically, the unmodified portion 10).

[0037] As shown in FIG. 1G, a structure 100 according to one embodiment of the present invention (hereinafter sometimes referred to as the "structure of this embodiment") has a substrate 101 having an unmodified portion 10 and a modified portion 20 on its surface, and a fine uneven structure layer 102 made of a UV-curable resin 160, which is arranged only on the modified portion 20 of the substrate 101.

[0038] <Substrate> The substrate 101 used in this embodiment is preferably formed from a cycloolefin resin. The substrate 101 used in this embodiment can be appropriately selected depending on the purpose, and examples thereof include COP and COC. The substrate 101 is preferably transparent. The surface of the substrate 101 may also be coated. Here, "transparent" means that the transmittance of light with wavelengths belonging to the visible light band (approximately 360 nm to 830 nm) is high, and for example, the transmittance of the light is 70% or more.

[0039] <Modified Section and Non-Modified Section> In this embodiment, the water droplet contact angle of the modified section 20 is preferably at least 40 degrees smaller than the water droplet contact angle of the non-modified section 10, more preferably at least 50 degrees smaller, and even more preferably at least 60 degrees smaller. The modified section 20 and the non-modified section 10 may be distinguished from each other by subjecting a portion of the surface of the substrate 101 to a surface modification treatment to form the modified section 20. Alternatively, the modified section 20 and the non-modified section 10 may be distinguished from each other by forming the non-modified section 10 from a first material in a first portion 10a of the surface of the substrate 101, and forming the modified section 20 from a second material different from the first material in a second portion 20a. For example, the first material may be a material different from the second material in the second portion 20a, such as fluorine or silicone.

[0040] <Fine Relief Structure Layer> The fine relief structure layer 102 of this embodiment has a fine relief pattern (protrusions that are protruding in the thickness direction of the fine relief structure and recesses that are recessed in the thickness direction of the fine relief structure). This can improve anti-reflection performance. The protrusions and recesses may be arranged periodically (for example, in a houndstooth or rectangular lattice pattern) or randomly. There are no particular restrictions on the shapes of the protrusions and recesses, and they may be bullet-shaped, cone-shaped, columnar, needle-shaped, or the like. The shape of the recesses refers to the shape formed by the inner walls of the recesses.

[0041] The thickness of the micro-relief structure layer 102 at the boundary between the modified portion 20 and the non-modified portion 10 (points A and B in Figure 1G) is preferably 1 μm or less, more preferably 0.5 μm or less, and even more preferably 0.1 μm or less.

[0042] Furthermore, the depth of the recesses (height of the protrusions) in the concave-convex pattern of the microrelief structure layer 102 is not particularly limited, but is preferably 150 nm or more, more preferably 190 nm or more, and preferably 500 nm or less, and more preferably 230 nm or less. On the other hand, the thickness of the non-microrelief structure portion of the microrelief structure layer 102 is preferably 250 nm or less. If the thickness of the non-microrelief structure portion of the microrelief structure layer 102 is 250 nm or less, the vibration (ripple) of the reflection spectrum caused by multiple reflections between the substrate 101 and the microrelief structure layer 102 is reduced, thereby further suppressing color unevenness or deterioration of reflection. From the same perspective, the thickness of the non-microrelief structure portion of the microrelief structure layer 102 is more preferably 200 nm or less, even more preferably 100 nm or less, and particularly preferably 50 nm or less. On the other hand, from a practical standpoint, the thickness of the non-microrelief structure portion of the microrelief structure layer 102 can be 0.01 nm or more. The thickness of the portion of the micro-relief structure layer 102 that is not a micro-relief structure refers to the distance in the stacking direction or film thickness direction between the surface where the micro-relief structure layer 102 and the substrate 101 contact and the apex of the deepest recess of the formed micro-relief structure.

[0043] The average period (pitch) of the concave-convex pattern on the upper surface of the microrelief structure layer 102 is preferably equal to or less than the wavelength of visible light (for example, 830 nm or less), more preferably equal to or less than 350 nm, even more preferably equal to or less than 280 nm, and more preferably equal to or greater than 100 nm, even more preferably equal to or greater than 150 nm. By making the pitch of the concave-convex pattern on the upper surface of the microrelief structure layer 102 equal to or less than the wavelength of visible light, in other words, by making the upper surface of the microrelief structure layer 102 have a so-called moth-eye structure, a structure with even greater anti-reflection performance can be achieved.

[0044] Here, the average period of the concave-convex pattern is the arithmetic mean value of the distances between adjacent convex portions and concave portions. The concave-convex pattern and thickness of the micro-convex structure layer 102 can be observed, for example, using a scanning electron microscope (SEM) or a cross-sectional transmission electron microscope (cross-sectional TEM). One method for calculating the average period is to pick several combinations of adjacent convex portions and several combinations of adjacent concave portions, measure the distances between the convex portions and the concave portions that make up each combination, and average the measured values.

[0045] The microrelief structure layer 102 used in this embodiment is made of a curable resin. The curable resin is not particularly limited, but may be, for example, a UV-curable resin 160. Examples of the UV-curable resin 160 include a UV-curable acrylic resin and a UV-curable epoxy resin.

[0046] In this embodiment, the refractive indexes of the substrate 101 and the microrelief structure layer 102 are n ０ , n １ When ０ and １ The absolute value of the difference in refractive index between the first and second layers is preferably within 0.2. By satisfying this condition, the vibration (ripple) of the reflection spectrum caused by multiple reflections between layers is reduced, color unevenness or deterioration of reflection is suppressed, and a structure with high transmittance can be obtained.

[0047] Next, the present invention will be described in more detail using examples and comparative examples, but the present invention is not limited to the following examples.

[0048] Example 1 According to the manufacturing method of the present invention, a structure 100 was produced by the method shown in FIGS. 1A to 1G, which includes a substrate 101 having an unmodified portion 10 and a modified portion 20 on its surface, and a microrelief structure layer 102 made of a UV-curable resin 160 and disposed only on the modified portion 20 of the substrate 101.

[0049] Specifically, a 3 mm-thick substrate 101 made of COC was prepared. The portion of the substrate 101 where the microrelief structure layer 102 would be formed was designated the second portion 20a, and the remaining portion was designated the first portion 10a. The first portion 10a on the surface of the substrate 101 was covered with a mask 150 ( FIG. 1A ). Next, the substrate 101 was irradiated with excimer light from above, and the second portion 20a on the surface of the substrate 101 was subjected to excimer treatment ( FIG. 1B ). The mask 150 covering the first portion 10a on the surface of the substrate 101 was removed. After removing the mask 150, the modified portion of the surface was designated the modified portion 20, and the unmodified portion was designated the unmodified portion 10 ( FIG. 1C ). Next, a UV-curable resin 160 was applied to the surface of the substrate 101 ( FIG. 1D ). A UV-curable resin (SK1120 manufactured by DXC) was used as the UV-curable resin 160. A film mold 250 having a moth-eye structure formed as a fine uneven structure was laminated on the UV-curable resin 160, and pressed at 0.1 MPa for 10 seconds. The fine uneven structure of the film mold 250 used was a moth-eye structure with a pitch of 200 nm and a depth of the recesses (height of the protrusions) of 200 nm. At this time, the film thickness of the UV-curable resin 160 was 0.1 μm. UV was irradiated from above the film mold 250 to harden the UV-curable resin 160 (FIG. 1E). The film mold 250 was peeled off, and a fine uneven structure layer 102 was formed (FIG. 1F). Next, the fine uneven structure layer 102 formed on the unmodified portion 10 was peeled off, leaving the structure 100 (FIG. 1G). The refractive index n of the substrate 101 was also determined. ０ is 1.52, and the refractive index n １ was set to 1.52.

[0050] The thickness of the microrelief structure layer 102 at the boundary between the modified section 20 (the section intended to form the microrelief structure) and the non-modified section 10 (the section not intended to form the microrelief structure) was approximately 0.1 μm. The thickness of the non-microrelief structure section of the microrelief structure layer 102 was also approximately 0.1 μm.

[0051] Next, the water droplet contact angle of the modified portion 20 of the structure 100 (the portion intended to form a microrelief structure), the water droplet contact angle of the unmodified portion 10 (the portion not intended to form a microrelief structure), the difference in water droplet contact angle between the modified portion 20 and the unmodified portion 10, peeling of excess curing agent, and spilling onto the edge were measured. The evaluation results are shown in Table 1. The water droplet contact angles of the modified portion 20 and the unmodified portion 10 were measured before applying the UV-curable resin 160 to the substrate 101. Furthermore, peeling of excess curing agent indicates whether or not the microrelief structure layer 102 formed on the unmodified portion 10 (the portion not intended to form a microrelief structure) is peeled off. Spilling onto the edge indicates the presence or absence of UV-curable resin 160 on the unmodified portion 10 (the portion not intended to form a microrelief structure).

[0052] Example 2 A structure 100 similar to that of Example 1 was produced, except that a film mold 250 with a 0.5 μm-thick thin-film carrier film having a fine uneven structure was used as a mold for forming the fine uneven structure in the UV-curable resin 160. The fine uneven structure of the film mold 250 with the carrier film attached was a moth-eye structure with a pitch of 200 nm and a recess depth (height of the protrusion) of 200 nm. The film mold 250 with the fine uneven structure was laminated on the UV-curable resin 160 and pressed at 0.1 MPa for 10 seconds. At this time, the thickness of the thinnest part of the UV-curable resin 160 was 0.1 μm. UV was irradiated from above the film mold 250 to harden the UV-curable resin 160, forming a peelable fine uneven structure layer 102. The thickness of the microrelief structure layer 102 at the boundary between the modified section 20 (the section intended to form a microrelief structure) and the non-modified section 10 (the section not intended to form a microrelief structure) was approximately 0.1 μm. The thickness of the non-microrelief structure section of the microrelief structure layer 102 was approximately 0.1 μm. As in Example 1, the water droplet contact angle of the modified section 20, the water droplet contact angle of the non-modified section 10, the difference in water droplet contact angle between the modified section 20 and the non-modified section 10, peeling of excess curing agent, and spillage onto the edge were evaluated. The results are shown in Table 1.

[0053] Comparative Example 1 A structure 100 similar to that of Example 1 was produced, except that during the modification process, the portions where the microrelief structure was not intended to be formed were not covered with a mask, and excimer treatment was performed to modify the entire surface of the substrate 101. The thickness of the microrelief structure layer 102 at the boundary between the portion where the microrelief structure was intended to be formed and the portion where the microrelief structure was not intended to be formed was 2 μm. The thickness of the portion of the microrelief structure layer 102 where the microrelief structure was not intended to be formed was also 2 μm. As in Example 1, the water droplet contact angle of the portion where the microrelief structure was intended to be formed, the water droplet contact angle of the portion where the microrelief structure was not intended to be formed, the difference therebetween, peeling of excess curing agent, and spillage onto the edge were evaluated. The results are shown in Table 1. The water droplet contact angle of the portion where the microrelief structure was intended to be formed and the water droplet contact angle of the portion where the microrelief structure was not intended to be formed were measured before applying the UV-curable resin 160 to the substrate 101.

[0054] Comparative Example 2 A structure 100 similar to that of Example 2 was produced, except that during the modification process, the portions where the microrelief structure was not intended to be formed were not covered with a mask, and excimer treatment was performed to modify the entire surface of the substrate 101. The thickness of the microrelief structure layer 102 at the boundary between the portion where the microrelief structure was intended to be formed and the portion where the microrelief structure was not intended to be formed was 2 μm. The thickness of the portion of the microrelief structure layer 102 where the microrelief structure was not intended to be formed was also 2 μm. As in Example 1, the water droplet contact angle of the portion where the microrelief structure was intended to be formed, the water droplet contact angle of the portion where the microrelief structure was not intended to be formed, the difference between them, peeling of excess curing agent, and spillage onto the edge were evaluated. The results are shown in Table 1. The water droplet contact angle of the portion where the microrelief structure was intended to be formed and the water droplet contact angle of the portion where the microrelief structure was not intended to be formed were measured before applying the UV-curable resin 160 to the substrate 101.

[0055]

[0056] From Table 1, it can be seen that in the structures 100 according to Examples 1 and 2, the difference in water droplet contact angle between the modified portion 20 (the portion intended to form a fine uneven structure) and the unmodified portion 10 (the portion not intended to form a fine uneven structure) is 40 degrees or more, and the excess curing agent can be peeled off and there is no spillage to the edge portion. Furthermore, it can be seen that the thickness of the fine uneven structure layer 102 at the boundary between the modified portion 20 and the unmodified portion 10 is 0.1 μm or less. On the other hand, in the structures 100 according to Comparative Examples 1 and 2, the difference in water droplet contact angle between the portion of the surface of the substrate 101 intended to form a fine uneven structure and the portion not intended to form a fine uneven structure is 0 degrees, so the excess curing agent cannot be peeled off and there is also spillage to the edge portion. Furthermore, it can be seen that the thickness of the fine uneven structure layer 102 at the boundary between the portion intended to form a fine uneven structure and the portion not intended to form a fine uneven structure is 2 μm.

[0057] According to the present invention, it is possible to easily provide a method for manufacturing a structure in which a microrelief structure is formed only in desired portions of a substrate, without the curable resin spilling out to the surrounding area, and the structure itself. According to the present invention, a microrelief structure can be formed without interfering with the original shape of the substrate on which the microrelief structure is formed, thereby suppressing problems such as malfunctions when setting the structure in a housing or optical alignment errors. Furthermore, according to the present invention, the curable resin spilling out to areas where the microrelief structure layer 102 is not intended to be formed also hardens, allowing the excess portion to be removed without contaminating the surrounding area. Therefore, a high-quality process can be realized.

[0058] REFERENCE SIGNS LIST 10 Non-modified portion 20 Modified portion 10a First portion 20a Second portion 100 Structure 101 Substrate 102 Microrelief structure layer 150 Mask 160 UV-curable resin 250 Film mold

Claims

1. A method for manufacturing a structure, comprising: a modification step of forming an unmodified portion and a modified portion on the surface of a substrate; a coating step of applying a curable resin to the surface; a structure formation step of forming a fine concavo-convex structure on the curable resin applied to the substrate; a curing step of curing the curable resin; and a removal step of removing the cured product of the curable resin applied to the unmodified portion.

2. The method for manufacturing a structure according to claim 1, wherein the modification step includes: a step of covering a first portion of the surface with a mask; a step of modifying a second portion of the surface that is not covered with the mask as the modified portion; and a step of removing the mask.

3. The method for manufacturing a structure according to claim 1, wherein the structure formation step is performed using a mold having an inverted shape of the fine concavo-convex structure.

4. The method for manufacturing a structure according to claim 1, wherein the water contact angle of the modified portion formed in the modification step is at least 40 degrees smaller than the water contact angle of the unmodified portion.

5. The method for manufacturing a structure according to claim 2, wherein the modifying step is performed by a surface modification treatment selected from the group consisting of excimer treatment, silane coupling treatment, and primer treatment.

6. The method for manufacturing a structure according to claim 1, wherein the modification step includes a material application step of forming the unmodified portion with a first material on a first portion of the surface and forming the modified portion with a second material different from the first material on a second portion of the surface different from the first portion.

7. The method for manufacturing a structure according to claim 1, wherein the substrate is formed of a cycloolefin resin.

8. A structure, comprising: a substrate having an unmodified portion and a modified portion on the surface; and a fine concavo-convex structure layer made of a curable resin disposed only on the modified portion of the substrate.

9. The structure according to claim 8, wherein the water contact angle of the modified portion is at least 40 degrees smaller than the water contact angle of the unmodified portion.

10. The structure according to claim 8, wherein the unmodified portion is formed of a first material on a first portion of the surface, and the modified portion is formed of a second material different from the first material on a second portion of the surface.

11. The structure according to claim 8, wherein the substrate is formed of a cycloolefin resin.

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