Optical element and light irradiation device

Abstract

To provide an optical element with which it is possible to suppress the ingress of an adhesive to an optical region and increase the ratio of the area of the optical region relative to the area of top surface of the optical element.SOLUTION: In the present invention, the above problem is solved by providing an optical element that comprises: a substrate; an optical function layer located on at least one surface of the substrate and having an optical region composed of irregularities on the side opposite the side that faces the substrate; and an adhesive ingress suppress region located in the recesses of the irregularities, for forming a closed curve that is continuous to the protrusions of the irregularities. The optical region includes a frame, an adhesive ingress suppress region that satisfies the range of distance from 0 μm over to less than 150 μm from the frame toward the inside, and a center region that is enclosed with the adhesive ingress suppress region. The closed curve is formed in the adhesive ingress suppress region so as to enclose the center region.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an optical element and a light irradiation device. [Background technology]

[0002] Optical elements are elements that exhibit various functions through the interaction between light and materials. One example of an optical element that can change the area illuminated by light is a diffractive optical element. A diffractive optical element is sometimes called a Diffractive Optical Element or DOE. The top surface of a DOE has an optical region in which materials with different refractive indices are arranged alternately. When one material is air, the optical region is composed of concaves and convexes caused by the other material. When light is incident on a DOE, a difference in optical path occurs between the light incident on the concaves and the light incident on the convex parts, causing the light to diffract. By utilizing the diffraction of light, the area illuminated by light can be changed.

[0003] Optical elements such as DOEs are used as light irradiation devices by combining them with light sources, etc. In the light irradiation device, the optical element is held away from the light source by a holder, etc. The optical element and the holder are fixed with an adhesive, etc. When adhesive is applied to the optical element, there is a risk that the adhesive will seep into the optical region, which is composed of irregularities, etc. If the adhesive seeps into the optical region, a problem may occur in which the optical element loses its function.

[0004] Patent Document 1 discloses an optical element that suppresses the infiltration of adhesive into a line-and-space grating pattern by forming adhesive reservoir grooves on both ends of the grating pattern. In the optical element disclosed in Patent Document 1, the adhesive reservoir groove consists of a single groove. Patent Document 2 discloses an optical element that suppresses the infiltration of adhesive into the lens side by providing two or more liquid retaining means on the outer periphery of the lens. In both of the optical elements disclosed in Patent Document 1 and Patent Document 2, the structure for suppressing the infiltration of adhesive is formed outside the optical region, such as the grating pattern and the lens.

[0005] As the optical element becomes smaller, the alignment margin between the optical region and the light source becomes insufficient in the optical elements described in Patent Documents 1 and 2. When the alignment margin between the optical region and the light source is insufficient, the risk of light leakage from the outside of the optical region increases. Therefore, it is desirable that the ratio of the area of ​​the optical region to the area of ​​the upper surface of the optical element is as large as possible. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2002-182025 A [Patent Document 2] JP 2009-251249 A Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention has been made in consideration of the above-mentioned situation, and aims to provide an optical element that can suppress the infiltration of adhesive into the optical region and increase the ratio of the area of ​​the optical region to the area of ​​the top surface of the optical element. [Means for solving the problem]

[0008] A first invention provides a method for manufacturing a semiconductor device comprising: a substrate; an optical functional layer located on at least one surface of the substrate, the optical functional layer having an optical region formed of concaves and convexes on a surface opposite to the surface facing the substrate; and an adhesive penetration suppression pattern located in a concave portion of the concaves and convexes and forming a closed curve continuous with a convex portion of the concaves and convexes, The optical region is an optical element having a frame, an adhesive infiltration suppression region which is a region that fills the distance range from 0 μm to 150 μm from the frame inward, and a central region which is a region surrounded by the adhesive infiltration suppression region, and the closed curve is formed in the adhesive infiltration suppression region so as to surround the central region.

[0009] The second invention is an optical element comprising an optical functional substrate having an optical region consisting of concaves and convexes on one surface, and an adhesive penetration suppression pattern located in the concaves of the concaves and convexities and forming a continuous closed curve with the convex parts of the concaves and convexities, wherein the optical region has a frame, an adhesive penetration suppression region which is a region that fills the distance range from greater than 0 μm to less than 150 μm from the frame inward, and a central region which is a region surrounded by the adhesive penetration suppression region, and the closed curve is formed in the adhesive penetration suppression region so as to surround the central region.

[0010] A third invention is the optical element according to the first or second invention, wherein an upper surface of the adhesive penetration suppression pattern is at the same height as an upper surface of the concaves and convexes.

[0011] A fourth invention is the optical element according to any one of the first to third inventions, wherein the closed curve is formed in two or more parts.

[0012] A fifth invention is the optical element according to the fourth invention, in which the ratio of the pitch of the two adhesive penetration suppression patterns facing each other in parallel to the wavelength of incident light is 0.2 or more and 2.0 or less.

[0013] A sixth invention is an optical element according to the fourth invention, in which the ratio of the pitch of the two adhesive penetration suppression patterns facing each other in parallel to the wavelength of incident light is 0.4 or more and 1.4 or less.

[0014] A seventh invention is the optical element according to any one of the first to sixth inventions, wherein the closed curve has an irregular shape.

[0015] An eighth invention is an optical element described in any one of the first to seventh inventions, wherein the unevenness has a pattern in which the boundary between the concave and convex portions includes a curve when viewed from the optical axis of the incident light.

[0016] A ninth invention is the optical element according to any one of the first to eighth inventions, wherein the optical region has a function of diffracting incident light.

[0017] A tenth invention is the optical element according to any one of the first to ninth inventions, wherein the adhesive penetration suppression pattern is made of an ultraviolet curable resin.

[0018] An eleventh aspect of the present invention is a light irradiation device comprising the optical element according to any one of the first to tenth aspects of the present invention. Effect of the Invention

[0019] As described above, according to the present invention, it is possible to provide an optical element that can suppress the infiltration of adhesive into the optical region and can increase the ratio of the area of ​​the optical region to the area of ​​the upper surface of the optical element. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 is a diagram showing the configuration of a light irradiation device 1. As shown in FIG. [Diagram 2] FIG. 2 is a diagram showing the transformation of the light irradiation area by the optical element 10. As shown in FIG. [Diagram 3] FIG. 3 is a diagram showing the configuration of the optical element 10. As shown in FIG. [Figure 4] FIG. 4 is a diagram showing the configuration of another embodiment of the optical element 10. In FIG. [Diagram 5] FIG. 5 is a cross-sectional view in the z direction of an optical region 5 consisting of n-level irregularities 5A. [Figure 6] FIG. 6 is a conceptual diagram showing the configuration of the irregularities 5A in the optical region 5. As shown in FIG. [Figure 7] FIG. 7 is a conceptual diagram showing the configuration of the optical region 5 of the GCA type. [Figure 8] FIG. 8 is a diagram showing the configuration of the adhesive infiltration suppression pattern 6. As shown in FIG. [Figure 9] FIG. 9 is a diagram showing the configuration of a closed curve L having a regular shape. [Figure 10]FIG. 10 is a diagram showing the configuration of a doubly formed closed curve L. [Figure 11] FIG. 11 is a diagram showing the pitch P of two adhesive intrusion suppression patterns 6 that face each other in parallel. [Figure 12] FIG. 12 is a diagram showing a method for producing the optical element 10 by the imprint method. [Figure 13] FIG. 13 is a diagram showing a method for producing the optical element 10 by etching. [Figure 14] FIG. 14 is a diagram showing observed images of the optical region 5 and the adhesive infiltration suppression pattern 6. As shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings attached to this specification, the scale and dimensional ratios are appropriately changed and exaggerated from those of the actual objects for the convenience of illustration and understanding.

[0022] In addition, terms used in this specification that specify shapes, geometric conditions, and the degree thereof, such as "parallel," "orthogonal," "identical," length, and angle values, etc., are not to be bound by their strict meanings, but are to be interpreted to include the extent to which similar functions can be expected.

[0023] The light irradiation device 1 is a device that irradiates light whose irradiation area has been transformed. FIG. 1 is a diagram showing the configuration of the light irradiation device 1. As shown in FIG. 1, a three-dimensional coordinate system consisting of an x-axis, a y-axis, and a z-axis is defined. The x-axis, the y-axis, and the z-axis are perpendicular to each other. FIG. 1(a) is a top view of the light irradiation device 1. FIG. 1(b) is a bottom view of the light irradiation device 1. FIG. 1(c) is a side view of the light irradiation device 1. FIG. 1(d) is a cross-sectional view of the light irradiation device 1 cut at the position of the arrow A-A' in FIG. 1(a). As shown in FIG. 1, the light irradiation device 1 includes a holder 2, a light source 3, an adhesive 4, and an optical element 10.

[0024] The holder 2 is a member for holding the optical element 10 in a state separated from the light source 3. The holder 2 is not particularly limited, and may have a shape as shown in FIG. 1, for example. The dimensions of the holder 2 may be, for example, 4×4 mm in outer dimensions of the top and bottom, 3×3 mm in opening of the top, 2×2 mm in opening of the bottom, and 2×4 mm in outer dimensions of the side. The material constituting the holder 2 may be, for example, acrylic or epoxy resin, glass, metal, etc.

[0025] The light source 3 is a device that emits light. The light source 3 is not particularly limited, and may be, for example, a vertical cavity surface emitting laser. The vertical cavity surface emitting laser is sometimes called a Vertical Cavity Surface Emitting Laser or VCSEL. The VCSEL has small characteristic changes with temperature changes, so it can emit stable light. As the light from the light source 3, for example, near-infrared light with a peak wavelength of 850 nm or 940 nm may be used. Since near-infrared light is invisible to the human eye, it does not interfere with the human field of vision. Furthermore, near-infrared light is not easily affected by external light in the environment in which it is used indoors.

[0026] The adhesive 4 is a member that fixes the optical element 10 to the holder 2. For example, the optical element 10 and the holder 2 are bonded together by applying the adhesive 4 to the interface between them. The adhesive 4 is not particularly limited, but may be, for example, an ultraviolet curing adhesive, a heat curing adhesive, or the like. By using an ultraviolet curing adhesive, a heat curing adhesive, or the like as the adhesive 4, it is possible to exert sufficient adhesive strength for the light irradiation device 1 to function stably.

[0027] The optical element 10 is an element that exhibits various functions through the interaction between light and matter. FIG. 2 is a diagram showing the conversion of the light irradiation area by the optical element 10. The pre-conversion irradiation area S1 and the post-conversion irradiation area S2 shown in FIG. 2 are merely examples. The pre-conversion irradiation area S1 is, for example, one circle. The light 30 passes through the optical area 5, whereby the irradiation area of ​​the light 30 is converted. The post-conversion irradiation area S2 can be, for example, nine circles on the screen 7. The light irradiation area can be freely controlled by performing optical design for the optical area 5.

[0028] The configuration of the optical element 10 will be described. Fig. 3 is a diagram showing the configuration of the optical element 10. Fig. 3(a) is a perspective view of the optical element 10. Fig. 3(b) is a cross-sectional view of the optical element 10 cut at the position of the arrow B-B' in Fig. 3(a). As shown in Fig. 3(b), the optical element 10 includes a substrate 11, an optical functional layer 12, and an adhesive intrusion suppression pattern 6.

[0029] The substrate 11 is a member for supporting the optical functional layer 12. The substrate 11 may have optical transparency. For example, quartz glass, soda glass, calcium fluoride, magnesium fluoride, barium borosilicate glass, amino borosilicate glass, polycarbonate, polyethylene terephthalate, methyl methacrylate butadiene styrene copolymer, methyl methacrylate styrene copolymer, acrylic styrene copolymer, acrylonitrile butadiene styrene copolymer, etc. may be used as the substrate 11.

[0030] When used as a reflective optical element, the base material 11 does not necessarily need to be light-transmitting.

[0031] The shape of the substrate 11 is not particularly limited, and may be, for example, a rectangular parallelepiped. The dimensions of the substrate 11 may be, for example, 3 mm×3 mm×0.5 mm. The ends of the substrate 11 may be chamfered. By chamfering the ends of the substrate 11, damage to the ends of the substrate 11 can be suppressed when the substrate 11 is transported, etc.

[0032] The optical functional layer 12 is a layer for forming the optical region 5. The optical functional layer 12 is located on at least one surface of the substrate. The optical functional layer 12 may have a thickness of, for example, 20 μm. The optical functional layer 12 may be formed by, for example, a spin coating method.

[0033] The optical functional layer 12 is not particularly limited, and may be, for example, an ultraviolet curable resin. The ultraviolet curable resin may be, for example, a resin mainly made of urethane acrylate, polyester acrylate, epoxy acrylate, polyether acrylate, polythiol, butadiene acrylate, etc. By forming the optical functional layer 12 from an ultraviolet curable resin, the optical region 5 can be easily formed by an imprint method or the like.

[0034] The optical function layer 12 may be formed of, for example, a thermosetting resin or an electron beam curable resin, or may be formed of a thermosetting or ultraviolet curable spin-on glass.

[0035] An adhesive layer may be formed between the substrate 11 and the optical functional layer 12. For example, a silane coupling agent or the like may be used as the adhesive layer. By forming the adhesive layer, the adhesiveness between the substrate 11 and the optical functional layer 12 can be improved. The improved adhesiveness can prevent the substrate 11 and the optical functional layer 12 from peeling off when the mold 8 is released from the optical functional layer 12 in the imprint method. Furthermore, when used as an optical element for a long period of time, the improved adhesiveness is often advantageous.

[0036] The substrate 11 and the optical functional layer 12 may be integrated into one layer as an optically functional substrate 13. Fig. 4 is a diagram showing another configuration of the optical element 10. Fig. 4(a) is a perspective view of the optical element 10. Fig. 4(b) is a cross-sectional view of the optical element 10 cut at the position of the arrow CC' in Fig. 4(a). As shown in Fig. 4(b), the optical element 10 includes an optically functional substrate 13 and an adhesive infiltration suppression pattern 6.

[0037] The optical function substrate 13 is a member for forming the optical region 5. The optical function substrate 13 is a member that can independently maintain its shape. The optical function substrate 13 may have optical transparency. As the optical function substrate 13, for example, quartz glass, soda glass, calcium fluoride, magnesium fluoride, barium borosilicate glass, amino borosilicate glass, polycarbonate, polyethylene terephthalate, methyl methacrylate butadiene styrene copolymer, methyl methacrylate styrene copolymer, acrylic styrene copolymer, acrylonitrile butadiene styrene copolymer, etc. may be used. The optical function substrate 13 can be formed with the optical region 5 by, for example, an etching method, an injection molding method, etc.

[0038] When used as a reflective optical element, the optically functional substrate 13 does not necessarily need to be light-transmitting.

[0039] The shape of the optically functional substrate 13 is not particularly limited, and may be, for example, a rectangular parallelepiped. The dimensions of the optically functional substrate 13 may be, for example, 3 mm×3 mm×0.5 mm. The ends of the optically functional substrate 13 may be chamfered. By chamfering the ends of the optically functional substrate 13, damage to the ends of the optically functional substrate 13 can be suppressed when the optically functional substrate 13 is transported, etc.

[0040] The optical functional layer 12 has an optical region 5 consisting of irregularities 5A on the surface opposite to the surface facing the substrate 11. In the case of the optically functional substrate 13, the optical region 5 consisting of irregularities 5A is provided on one surface. The optical region 5 is a region that exhibits an optical function for incident light. The optical function may be a function due to the diffraction or refraction of light, etc.

[0041] 3(a) and 4(a), the optical region 5 has a frame 50, an adhesive infiltration suppression region 51, and a central region 52. The frame 50 is a line that defines the outer shape of the optical region 5. The shape of the frame 50 is not particularly limited, and may be, for example, a rectangle, a circle, or the like.

[0042] The adhesive infiltration suppression region 51 is a region in which the adhesive infiltration suppression pattern 6 is formed. The adhesive infiltration suppression region 51 is a region that fills a distance range greater than 0 μm and less than 150 μm from the frame 50 toward the inside. By setting the adhesive infiltration suppression region 51 to a distance range greater than 0 μm, the adhesive infiltration suppression pattern 6 can be formed in the vicinity of the frame 50. Furthermore, by setting the adhesive infiltration suppression region 51 to a distance range less than 150 μm, a sufficient range for providing the adhesive infiltration suppression pattern 6 described later can be secured. Furthermore, even when considering alignment errors in the xy directions between the light source 3 and the optical region 5, light leakage from outside the optical region can be sufficiently suppressed. The shape of the adhesive infiltration suppression region 51 is determined by the shape of the frame 50.

[0043] The central region 52 is a region where the adhesive infiltration suppression pattern 6 is not formed. The central region 52 is a region surrounded by the adhesive infiltration suppression region 51. The shape of the central region 52 is determined by the shapes of the frame 50 and the adhesive infiltration suppression region 51.

[0044] As shown in FIG. 3(b) and FIG. 4(b), the optical region 5 is configured with irregularities 5A in a cross section in the z-axis direction. The irregularities 5A have recesses 5B and protrusions 5C. The recesses 5B are portions occupied by air. The protrusions 5C are portions occupied by materials constituting the optical function layer 12 or the optical function substrate 13. The recesses 5B and the protrusions 5C are configured by substances with different refractive indices. An optical path difference occurs between the light incident on the recesses 5B and the light incident on the protrusions 5C, and therefore the optical function can be realized.

[0045] The unevenness 5A is not limited to the two-level example shown in FIG. 3(b) and FIG. 4(b), but may have three or more levels. FIG. 5 is a cross-sectional view in the z direction of the optical region 5 consisting of n-level unevenness 5A. In FIG. 5, the adhesive infiltration suppression pattern 6 is omitted. n is a natural number of 2 or more. The n-level means that the maximum number of steps of the unevenness 5A is n. As shown in FIG. 8, unevenness 5A with a number of steps less than n may exist. The larger the value of n, the more accurately the light irradiation region can be controlled.

[0046] The unevenness 5A may have a pattern in which the boundary between the recessed portion 5B and the protruding portion 5C includes a curve when viewed from the optical axis of the incident light. FIG. 6 is a conceptual diagram showing the configuration of the unevenness 5A in the optical region 5. In FIG. 6, the adhesive penetration suppression pattern 6 is omitted. The optical axis of the incident light is the z-axis in FIG. 6. The boundary between the recessed portion 5B and the protruding portion 5C is the interface between the air constituting the recessed portion 5B and the material constituting the protruding portion 5C. The curve may be, for example, a wavy line, a broken line, or a combination of these. By including a curve in the boundary between the recessed portion 5B and the protruding portion 5C, the light irradiation region can be controlled more accurately.

[0047] The optical region 5 may be a pattern in which unit cells 53 each having the same concave and convex portions 5A are arranged. The pattern in which the unit cells 53 are arranged is called a grating cell array type. The grating cell array type is also called a Grating Cell Array type or a GCA type. FIG. 7 is a conceptual diagram showing the configuration of a GCA type optical region 5. FIG. 7 shows an example of a GCA type optical region 5 in which nine unit cells 53 are arranged. The GCA type optical region 5 may be arranged such that each unit cell 53 is oriented in a different direction. By using a GCA type optical region 5, the light irradiation region can be controlled more accurately.

[0048] The width of the recesses 5B and the protrusions 5C on the upper surface of the irregularity 5A may be, for example, 0.1 μm or more and 20 μm or less. The depth of the recesses 5B, i.e., the height of the protrusions 5C may be, for example, 0.1 μm or more and 3 μm or less. The pitch of the irregularities 5A may be, for example, 0.2 μm or more and 40 μm or less.

[0049] The adhesive infiltration suppression pattern 6 is a pattern that has the function of blocking the adhesive 4. FIG. 8 is a diagram showing the configuration of the adhesive infiltration suppression pattern 6. The adhesive infiltration suppression pattern 6 is located in the recess 5B, and forms a closed curve L that is continuous with the protrusion 5C. A closed curve is a curve whose starting point and ending point coincide. Continuous means a state in which one pattern is connected to the other. As shown in FIG. 8, when the adhesive infiltration suppression pattern 6 and the protrusion 5C that is continuous with the adhesive infiltration suppression pattern 6 are connected together, it can be seen that a closed curve L is formed.

[0050] FIG. 8(a) is a diagram showing the optical region 5 and the adhesive infiltration suppression pattern 6. Since the adhesive infiltration suppression pattern 6 is located in the recess 5B, it is not necessary to form the adhesive infiltration suppression pattern 6 outside the optical region 5, so that the ratio of the area of ​​the optical region 5 to the area of ​​the upper surface of the optical element 10 can be increased. Furthermore, since the adhesive infiltration suppression pattern 6 is located in the recess 5B, it is possible to partially leave the outline of the convex portion 5C, and it is possible to suppress the loss of the optical function of the optical region 5. And, since the adhesive infiltration suppression pattern 6 forms a closed curve L continuous with the convex portion 5C, it is possible to suppress the infiltration of the adhesive 4 into the optical region 5. Therefore, it is possible to suppress the loss of the optical function of the optical region 5.

[0051] The closed curve L is formed in the adhesive infiltration suppression region 51 so as to surround the central region 52. Fig. 8(b) is a diagram in which only the portion forming the closed curve L is extracted from Fig. 8(a) and the adhesive infiltration suppression region 51 and the central region 52 are superimposed. By forming the closed curve L in the adhesive infiltration suppression region 51 so as to surround the central region 52, the adhesive infiltration suppression pattern 6 can be formed in the vicinity of the frame 50. Therefore, irradiation of the adhesive infiltration suppression pattern 6 with incident light can be suppressed.

[0052] The width of the adhesive infiltration suppression pattern 6 may be, for example, 0.1 μm or more and 20 μm or less. The height of the adhesive infiltration suppression pattern 6 may be, for example, 0.1 μm or more and 3 μm or less. The upper surface of the adhesive infiltration suppression pattern 6 may be at the same height as the upper surface of the unevenness 5A. By having the upper surface of the adhesive infiltration suppression pattern 6 and the upper surface of the unevenness 5A at the same height, infiltration of the adhesive 4 into the optical region 5 can be more reliably suppressed.

[0053] The closed curve L may have an irregular shape. Irregular means that the shape is not a regular shape such as a rectangle or a circle. In the example shown in FIG. 8(a), the closed curve L has an irregular shape. When the closed curve L has an irregular shape, the diffraction direction of the light irradiated to each adhesive infiltration suppression pattern 6 becomes irregular, so that the adhesive infiltration suppression pattern 6 can be made invisible. Therefore, it is possible to suppress the position of the adhesive infiltration suppression pattern 6 from being identified.

[0054] The closed curve L may have a regular shape such as a rectangle or a circle. Fig. 9 is a diagram showing the configuration of a regular shaped closed curve L. Fig. 9(a) is a diagram showing the configuration of a rectangular closed curve L. Fig. 9(b) is a diagram showing the configuration of a circular closed curve L. The regular shape of the closed curve L can simplify the design of the adhesive infiltration suppression pattern 6. Therefore, the time required to design the adhesive infiltration suppression pattern 6 can be shortened.

[0055] The closed curve L may be formed in two or more layers. Fig. 10 is a diagram showing the configuration of the closed curve L formed in two layers. Fig. 10(a) is a diagram showing the configuration of the closed curve L formed in two layers and having an irregular shape. Fig. 10(b) is a diagram showing the configuration of the closed curve L formed in two layers and having a regular shape. By forming the closed curve L in two or more layers, it is possible to more reliably suppress the infiltration of the adhesive 4 into the optical region 5.

[0056] 11 is a diagram showing the pitch P of two parallel adhesive infiltration suppression patterns 6. The pitch P is the distance between corresponding side surfaces of two parallel adhesive infiltration suppression patterns 6 when the closed curve L is formed in two or more portions.

[0057] According to the principle of diffraction, the following formula (1) holds between the pitch P, the wavelength λ of the incident light, and the diffraction angle θ of the light.

[0058]

number

[0059]

number

[0060] Here, it is widely known that it is difficult for a diffractive optical element to control zero-order light, that is, light that has the same shape and axis as the light before conversion. It is also widely known that when the phase difference between the pattern portion and the air portion is 180°, the intensity of the zero-order light is at a minimum, and when the phase difference is close to 180°, it becomes easier to control the intensity of the zero-order light.

[0061] For example, when the phase difference is set to 180° in a pattern material with a refractive index of 1.5, the wavelength λ of the incident light and the pattern height h are equal according to formula (2). However, the relationship between λ and h may change when the intensity of the zero-order light is controlled to a constant level or in a diffractive optical element whose pattern material is not 1.5, so the present invention does not need to be limited to λ=h. The ratio P / λ may be 0.2 or more and 2.0 or less, preferably 0.4 or more and 1.4 or less, and more preferably 0.4 or more and less than 1.0. The reason for this will be explained below.

[0062] The aspect ratio of the adhesive infiltration suppression pattern 6 is preferably 10 or less. For example, if the width of the adhesive infiltration suppression pattern 6 is d, the height of the adhesive infiltration suppression pattern 6 is preferably 10d or less. The wavelength λ of the incident light is preferably equal to the height of the adhesive infiltration suppression pattern 6, and therefore is 10d or less. The pitch P is preferably twice the width of the adhesive infiltration suppression pattern 6, and therefore is 2d. That is, in order to make the aspect ratio of the adhesive infiltration suppression pattern 6 10 or less, the ratio P / λ needs to be 0.2 or more. By making the ratio P / λ 0.2 or more, the aspect ratio of the adhesive infiltration suppression pattern 6 is 10 or less, and therefore the collapse of the adhesive infiltration suppression pattern 6 can be suppressed.

[0063] It is more preferable that the aspect ratio of the adhesive infiltration suppression pattern 6 is 5.0 or less. For example, if the width of the adhesive infiltration suppression pattern 6 is d, the height of the adhesive infiltration suppression pattern 6 is preferably 5.0d or less. The wavelength λ of the incident light is preferably equal to the height of the adhesive infiltration suppression pattern 6, and therefore is 5.0d or less. The pitch P is preferably twice the width of the adhesive infiltration suppression pattern 6, and therefore is 2d. That is, in order to make the aspect ratio of the adhesive infiltration suppression pattern 6 5.0 or less, the ratio P / λ needs to be 0.4 or more. By making the ratio P / λ 0.4 or more, the aspect ratio of the adhesive infiltration suppression pattern 6 is 5.0 or less, and therefore the collapse of the adhesive infiltration suppression pattern 6 can be more reliably suppressed.

[0064] The diffraction angle θ of light by the adhesive infiltration suppression pattern 6 is preferably 30° or more. In other words, sinθ is preferably 0.5 or more. From formula (1), the ratio P / λ is preferably 2.0 or less. By setting the ratio P / λ to 2.0 or less, the diffraction angle θ of light can be made 30° or more. For example, when the effective irradiation area provided by the optical area 5 is ±30°, which is about the angle of view of a typical camera, the diffracted light that becomes noise caused by the adhesive infiltration suppression pattern 6 can be made to escape to the outside of the effective irradiation area.

[0065] It is more preferable that the diffraction angle θ of light by the adhesive infiltration suppression pattern 6 is 45° or more. In other words, it is preferable that sinθ is 1 / √2 or more. From formula (1), it is preferable that the ratio P / λ is 1.4 or less. By setting the ratio P / λ to 1.4 or less, the diffraction angle θ of light can be made 45° or more. For example, when the effective irradiation area provided by the optical area 5 is ±30°, which is about the angle of view of a typical camera, the diffracted light that becomes noise generated by the adhesive infiltration suppression pattern 6 can be more reliably guided outside the effective irradiation area.

[0066] It is even more preferable that the adhesive infiltration suppression pattern 6 does not diffract light. sinθ is a value between 0 and 1.0. In formula (1), when sinθ is greater than 1, that is, when the ratio P / λ is less than 1.0, light is not diffracted. Therefore, even if incident light is irradiated onto the adhesive infiltration suppression pattern 6, the diffraction of light can be suppressed. Therefore, by making the ratio P / λ less than 1.0, diffracted light that can become noise caused by the adhesive infiltration suppression pattern 6 can be suppressed.

[0067] In view of the above, the ratio P / λ may be 0.2 or more and 2.0 or less, preferably 0.4 or more and 1.4 or less, and more preferably 0.4 or more and less than 1.0.

[0068] The adhesive infiltration suppression pattern 6 may be made of an ultraviolet curable resin or the like, similar to the optical functional layer 12. By making the adhesive infiltration suppression pattern 6 out of an ultraviolet curable resin, the concaves and convexes 5A and the adhesive infiltration suppression pattern 6 can be formed simultaneously. This allows the time required to manufacture the optical element 10 to be shortened.

[0069] The optical region 5 and the adhesive infiltration suppression pattern 6 may be formed by an imprinting method. FIG. 12 is a diagram showing a method for producing an optical element 10 by an imprinting method. As shown in FIG. 12(a), a substrate 11 is prepared. As shown in FIG. 12(b), an ultraviolet curable resin is applied onto one surface of the substrate 11 to form an uncured optical functional layer 12. As shown in FIG. 12(c), the uneven surface of the mold 8 is pressed against the surface of the optical functional layer 12 opposite to the surface facing the substrate 11. The uneven surface of the mold 8 has a pattern that is an inversion of the unevenness 5A and the adhesive infiltration suppression pattern 6. As shown in FIG. 12(d), the optical functional layer 12 is cured by irradiating the optical functional layer 12 with ultraviolet light UV from the back side of the mold 8. As shown in FIG. 12(e), the mold 8 is released from the optical functional layer 12 to form the optical region 5 and the adhesive infiltration suppression pattern 6 in the optical functional layer 12. The optical element 10 is completed by a series of steps shown in FIG. 12.

[0070] The mold 8 is preferably made of a material that transmits ultraviolet light UV. A master mold made of quartz glass or the like may be used as the mold 8. Also, a resin replica mold replicated from the master mold may be used as the mold 8.

[0071] The optical region 5 and the adhesive infiltration suppression pattern 6 may be formed by a method other than the imprint method, such as a lithography method including photolithography and electron beam lithography.

[0072] 12(e), the substrate 11 may be etched using the optical functional layer 12 as a mask. Since the optical region 5 and the adhesive infiltration suppression pattern 6 are formed in the substrate 11, the optical element 10 in which the substrate 11 serves as the optical functional substrate 13 can be obtained.

[0073] FIG. 13 is a diagram showing a method for producing an optical element 10 by etching. FIG. 13(a) is a diagram showing the optical element 10 shown in FIG. 12(e) in which the substrate 11 is replaced with an optically functional substrate 13. As shown in FIG. 13(b), the optically functional layer 12 and the optically functional substrate 13 are anisotropically etched using an etching gas. Argon or the like may be used as the etching gas. By using argon as the etching gas, it is possible to suppress the etching gas from chemically reacting with the optically functional layer 12 and the optically functional substrate 13. As shown in FIG. 13(c), the optical element 10 is completed by removing the remaining film of the optically functional layer 12. When the optically functional layer 12 is an ultraviolet curable resin, the remaining film of the optically functional layer 12 may be removed by reactive ion etching using oxygen plasma or the like. When the optically functional substrate 13 is quartz glass, the optically functional substrate 13 is not etched by reactive ion etching using oxygen plasma, so that only the remaining film of the optically functional layer 12 can be removed.

[0074] A hard mask may be formed between the optical functional layer 12 and the optical functional substrate 13. A metal such as chromium may be used as the hard mask. By forming a hard mask between the optical functional layer 12 and the optical functional substrate 13, the line edge roughness of the optical region 5 and the adhesive infiltration suppression pattern 6 can be reduced. EXAMPLES

[0075] The present invention will be described in more detail below with reference to examples.

[0076] A pattern consisting of an optical region and an adhesive infiltration suppression pattern was designed. In the optical region, the width of the concave portion was 1 μm, the width of the convex portion was 1 μm, and the height of the convex portion was 1 μm. In the adhesive infiltration suppression pattern, the width was 300 nm and the pitch was 600 nm.

[0077] A mold pattern was designed by inverting the designed pattern. The mold pattern was formed on a quartz substrate by lithography. The quartz substrate on which the mold pattern was formed was used as a mold.

[0078] A glass substrate with a thickness of 0.5 mm was prepared. Uncured UV-curable resin was applied to the glass substrate to a film thickness of 20 μm. A mold was pressed onto the UV-curable resin. The UV-curable resin was cured by irradiating it with UV rays through the mold. The mold was released from the UV-curable resin to form an optical region and an adhesive infiltration suppression pattern in the UV-curable resin, producing an optical element.

[0079] The conductivity was improved by sputtering platinum-palladium to a thickness of 2 nm on the UV-curable resin on which the optical region and adhesive penetration suppression pattern were formed. The optical region and adhesive penetration suppression pattern were observed using a scanning electron microscope. Scanning electron microscopes are also called Scanning Electron Microscopes or SEMs. The conditions for SEM observation were an acceleration voltage of 5 kV, a numerical aperture of 30 μm, and a working distance of 3 mm.

[0080] Fig. 14 is a diagram showing an observed image of the optical region and the adhesive infiltration suppression pattern. From Fig. 14, it was confirmed that the adhesive infiltration suppression pattern was located in the recess. This enabled the ratio of the area of ​​the optical region to the area of ​​the top surface of the optical element to be increased.

[0081] The optical element of the present invention can be used in a light irradiation device for three-dimensional face authentication, for example, to enhance security in electronic devices such as smartphones. [Explanation of symbols]

[0082] 1 Light irradiation device 10 Optical elements 11 Base material 12 Optical functional layer 13 Optical functional substrate 2 Holder 3 light source 4. Glue 5 Optical area 50 slots 51 Adhesive penetration suppression area 52 Central area 53 Unit Cell 5A unevenness 5B Recess 5C Convex 6 Adhesive penetration prevention pattern 7 Screen 8. Mold 8A Pattern surface 8B Back S1 Pre-conversion irradiation area S2 Post-conversion irradiation area L closed curve Pitch UV ultraviolet light

Claims

1. A substrate; An optical functional layer located on at least one surface of the substrate, the optical functional layer having an optical region having projections and recesses on a surface opposite to the surface facing the substrate; an adhesive infiltration suppression pattern that is located in a concave portion of the concave portion and forms a continuous closed curve with the convex portion of the concave portion, The optical region has a frame, an adhesive infiltration suppression region that is a region that satisfies a distance range of more than 0 μm and less than 150 μm from the frame toward the inside, and a central region that is a region surrounded by the adhesive infiltration suppression region, The closed curve is formed in the adhesive penetration suppression region so as to surround the central region. Optical elements.

2. An optically functional substrate having an optical region formed of projections and recesses on one surface thereof; an adhesive infiltration suppression pattern that is located in a concave portion of the concave portion and forms a continuous closed curve with the convex portion of the concave portion, The optical region has a frame, an adhesive infiltration suppression region that is a region that satisfies a distance range of more than 0 μm and less than 150 μm from the frame toward the inside, and a central region that is a region surrounded by the adhesive infiltration suppression region, The closed curve is formed in the adhesive penetration suppression region so as to surround the central region. Optical elements.

3. The upper surface of the adhesive penetration suppression pattern is at the same height as the upper surface of the unevenness. The optical element according to claim 1 .

4. The closed curve is formed in two or more parts. The optical element according to claim 1 .

5. 5. The optical element according to claim 4, a ratio of the pitch of the two adhesive infiltration suppression patterns facing each other in parallel to the wavelength of incident light is 0.2 or more and 2.0 or less; Optical elements.

6. 5. The optical element according to claim 4, a ratio of the pitch of the two adhesive infiltration suppression patterns facing each other in parallel to the wavelength of incident light is 0.4 or more and 1.4 or less; Optical elements.

7. The closed curve is an irregular shape. The optical element according to claim 1 .

8. The unevenness has a pattern in which the boundaries between the concave portions and the convex portions include curved lines when viewed from the optical axis of the incident light. The optical element according to claim 1 .

9. The optical region has a function of diffracting incident light.

9. The optical element according to claim 1.

10. The adhesive penetration suppression pattern is made of an ultraviolet curable resin.

10. The optical element according to claim 1 .

11. An optical element comprising the optical element according to any one of claims 1 to 10. Light irradiation device.

Images