JP2023084865A - Optical element and light irradiation device - Google Patents

Abstract

To provide an optical element inhibiting adhesive from immersing into an optical area.SOLUTION: The optical element comprises: a substrate; and an optical functional layer positioned on at least one surface of the substrate. The optical functional layer includes, on its surface opposite the surface facing the substrate, an optical area and a first adhesive immersion suppression area positioned on the periphery of the optical area. The optical area includes an optical pattern composed of recesses and protrusions. The first adhesive immersion suppression area includes a first adhesive immersion suppression pattern composed of grooves. (D1/W1) is greater than (D0/W0), where an opening width of the recess of the optical pattern is denoted by W0, a depth of the recess of the optical pattern is denoted by D0, an opening width of the first adhesive immersion suppression pattern is denoted by W1, and a depth of the first adhesive immersion suppression pattern is denoted by D1.SELECTED DRAWING: Figure 3

Description

The present invention relates to an optical element and a light irradiation device.

An optical element is an element that exhibits various functions through interaction between light and matter. As an optical element for converting the light irradiation area, for example, there is a diffractive optical element. Diffractive optical elements are sometimes called Diffractive Optical Elements or DOEs. The top surface of the DOE has optical regions with alternating materials of different refractive indices. When one material is air, the optical region is composed of irregularities due to the other material. When light enters the DOE, the light is diffracted because an optical path difference occurs between the light incident on the concave portion and the incident light on the convex portion. By utilizing the diffraction of light, the light irradiation area can be converted.

An optical element such as a DOE is used as a light irradiation device in combination with a light source or the like. In the light irradiation device, the optical element is held in a state separated from the light source by a holder or the like. The optical element and the holder are fixed with an adhesive or the like. When the adhesive is applied to the optical element, there is a risk that the adhesive will penetrate into the optical region formed by unevenness or the like. Penetration of the adhesive into the optical area can cause problems with the optical element becoming non-functional.

Japanese Patent Application Laid-Open No. 2002-200000 discloses an optical element that suppresses penetration of an adhesive into a grating pattern by forming adhesive reservoir grooves at both ends of the grating pattern in the form of lines and spaces. In the optical element described in Patent Document 1, the adhesive is stored in the adhesive reservoir grooves, thereby suppressing the penetration of the adhesive into the grating pattern. In this case, the adhesive accumulating groove must have a sufficient volume for accumulating the adhesive.

JP 2002-182025 A

SUMMARY OF THE INVENTION It is an object of the present invention to provide an optical element capable of suppressing penetration of an adhesive into an optical region.

A first invention comprises a substrate and an optical functional layer located on at least one surface of the substrate, the optical functional layer having an optical It has a first adhesive permeation suppression region located on the perimeter of the region and the optical region, the optical region has an optical pattern made up of recesses and protrusions, and the first adhesive permeation suppression region is a first adhesive permeation suppression region made up of grooves. It has an adhesive permeation suppression pattern, the aperture width of the recess of the optical pattern is W0, the depth of the recess of the optical pattern is D0, the aperture width of the first adhesive permeation suppression pattern is W1, and the first adhesive permeation Assuming that the depth of the suppression pattern is D1, (D1/W1) is an optical element larger than (D0/W0).

A second invention is provided with an optical functional base material having, on one surface, an optical region and a first adhesive penetration suppression region located on the outer periphery of the optical region, wherein the optical region is an optical pattern consisting of concave portions and convex portions. The first adhesive permeation suppression area has a first adhesive permeation suppression pattern consisting of grooves, the opening width of the concave portion of the optical pattern is W0, the depth of the concave portion of the optical pattern is D0, and the Assuming that the width of the first adhesive permeation suppression pattern is W1 and the depth of the first adhesive permeation suppression pattern is D1, (D1/W1) is greater than (D0/W0) in the optical element.

A third invention is the optical element according to the first invention or the second invention, wherein the first adhesive permeation suppression pattern forms a first closed curve surrounding the optical region.

A fourth invention is the optical element according to the third invention, wherein the shape of the first closed curve is the same as the shape of the frame of the optical region.

A fifth invention is the optical element according to the third invention or the fourth invention, wherein the first closed curve is formed in two or more.

A sixth invention is the optical element according to any one of the first invention to the fifth invention, wherein the first adhesive penetration suppression area has a mark.

A seventh invention is the optical element according to the sixth invention, wherein the mark is a groove and is mixed with the first adhesive permeation suppression pattern.

In an eighth aspect of the invention, the optical region comprises a frame, a second adhesive permeation suppression region which is a region satisfying a range of a distance greater than 0 μm and less than 150 μm toward the inside from the frame, and a second adhesive permeation suppression region. and a central region that is an enclosed region, wherein the second adhesive permeation suppression region is located in the concave portion of the optical region and forms a second closed curve that is continuous with the convex portion of the optical region. The optical element according to any one of the first to seventh inventions, which has a suppression pattern and the second closed curve is formed so as to surround the central region.

A ninth invention is the optical element according to the eighth invention, wherein the top surface of the second adhesive permeation suppression pattern is at the same height as the top surface of the convex portion of the optical region.

A tenth invention is the optical element according to the eighth invention or the ninth invention, wherein the second closed curve is formed in two or more.

An eleventh invention is the optical element according to the tenth invention, wherein the ratio of the pitch of the two second adhesive permeation suppression patterns that face each other in parallel to the wavelength of the incident light is 0.2 or more and 2.0 or less. is an optical element.

A twelfth invention is the optical element according to the tenth invention, wherein the ratio of the pitch of the two second adhesive permeation suppression patterns facing each other in parallel to the wavelength of the incident light is 0.4 or more and 1.4 or less. is an optical element.

A thirteenth invention is the optical element according to any one of the eighth invention to the twelfth invention, wherein the second closed curve has an irregular shape.

A fourteenth invention is the optical element according to any one of the eighth invention to the thirteenth invention, wherein the second adhesive permeation suppression pattern is made of an ultraviolet curable resin.

A fifteenth invention is the optical pattern according to any one of the first invention to the fourteenth invention, wherein the optical pattern has a pattern in which a boundary between the concave portion and the convex portion includes a curved line when viewed from the optical axis of the incident light. It is an optical element.

A sixteenth invention is the optical element according to any one of the first to fifteenth inventions, wherein the optical pattern has a function of diffracting incident light.

A seventeenth invention is a light irradiation device comprising the optical element according to any one of the first invention to the sixteenth invention.

As described above, according to the present invention, it is possible to provide an optical element capable of suppressing penetration of the adhesive into the optical region.

FIG. 1 is a diagram showing the configuration of a light irradiation device 1. As shown in FIG. FIG. 2 is a diagram showing how the optical element 10 converts the light irradiation area. FIG. 3 is a diagram showing the configuration of the optical element 10. As shown in FIG. FIG. 4 is a diagram showing another configuration of the optical element 10. As shown in FIG. FIG. 5 is a cross-sectional view in the z-direction of the optical region 5 consisting of the n-level optical pattern 5A. FIG. 6 is a conceptual diagram showing the configuration of the optical pattern 5A in the optical region 5. As shown in FIG. FIG. 7 is a conceptual diagram showing the configuration of the GCA-type optical region 5. As shown in FIG. FIG. 8 is an enlarged sectional view along the z-axis of the recess 5B of the optical pattern 5A and the first adhesive permeation suppression pattern 6A. FIG. 9 is a diagram showing a form example of the first adhesive permeation suppression pattern 6A when viewed from the z-axis direction. FIG. 10 is a diagram showing an arrangement example of the marks 9. As shown in FIG. FIG. 11 is a diagram showing the form of the mark 9. As shown in FIG. FIG. 12 is a diagram showing the configuration of the optical region 5. As shown in FIG. FIG. 13 is a diagram showing the configuration of the adhesive penetration suppression pattern 6. As shown in FIG. FIG. 14 is a diagram showing the configuration of a closed curve L with a regular shape. FIG. 15 is a diagram showing the structure of a closed curve L formed doubly. FIG. 16 is a diagram showing the pitch P of two adhesive permeation suppression patterns 6 facing each other in parallel. FIG. 17 is a diagram showing a method of manufacturing the optical element 10 by imprinting. FIG. 18 is a diagram showing a method of manufacturing the optical element 10 by etching. FIG. 19 is a diagram showing how isopropyl alcohol is dropped from the outside of the first adhesive permeation suppression pattern.

EMBODIMENT OF THE INVENTION Hereinafter, the form for implementing this invention is demonstrated with reference to drawings. In the drawings attached to this specification, for the convenience of illustration and easy understanding, scales, dimensional ratios, etc. are appropriately changed and exaggerated from those of the real thing.

Also, terms such as "parallel," "perpendicular," "identical," length and angle values, etc. that specify shapes and geometric conditions and degrees thereof, as used herein, are not strictly defined. Without being bound by the meaning, it is interpreted to include the extent to which similar functions can be expected.

The light irradiation device 1 is a device that irradiates light whose irradiation area has been converted. FIG. 1 is a diagram showing the configuration of a light irradiation device 1. As shown in FIG. As shown in FIG. 1, a three-dimensional coordinate system consisting of x-, y-, and z-axes is defined. The x-, y-, and z-axes are orthogonal to each other. FIG. 1(a) is a top view of the light irradiation device 1. FIG. FIG. 1B is a bottom view of the light irradiation device 1. FIG. FIG. 1(c) is a side view of the light irradiation device 1. FIG. FIG. 1(d) is a cross-sectional view of the light irradiation device 1 taken along the line AA 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 .

The holder 2 is a member for holding the optical element 10 away from the light source 3 . Although the holder 2 is not particularly limited, it may have the shape shown in FIG. 1, for example. Regarding the dimensions of the holder 2, for example, the top and bottom surfaces may be 4×4 mm, the top opening may be 3×3 mm, the bottom opening may be 2×2 mm, and the side surface may be 2×4 mm. The material forming the holder 2 may be, for example, acrylic or epoxy resin, glass, metal, or the like.

The light source 3 is a device that emits light. The light source 3 is not particularly limited, but may be, for example, a vertical cavity surface emitting laser. Vertical cavity surface emitting lasers are sometimes called Vertical Cavity Surface Emitting Lasers or VCSELs. A VCSEL can emit stable light because its characteristics change little with temperature changes. As the light from the light source 3, for example, near-infrared light with a peak wavelength of 850 nm, 940 nm, or the like may be used. Since near-infrared light is invisible to the human eye, it does not interfere with human vision. In addition, near-infrared light is less likely to be affected by the external light of the environment in which it is used indoors.

The adhesive 4 is a member that fixes the optical element 10 to the holder 2 . For example, by applying an adhesive 4 to the interface between the optical element 10 and the holder 2, the two are bonded together. 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 curable adhesive, a heat curable adhesive, or the like as the adhesive 4, it is possible to exhibit sufficient adhesive strength for the light irradiation device 1 to function stably.

The optical element 10 is an element that exhibits various functions through interaction between light and matter. FIG. 2 is a diagram showing how the optical element 10 converts the light irradiation area. The pre-conversion irradiation region S1 and the post-conversion irradiation region S2 shown in FIG. 2 are merely examples. The pre-conversion irradiation area S1 is, for example, one circle. As the light 30 passes through the optical region 5, the irradiation region of the light 30 is transformed. The post-conversion illumination areas S2 can be nine circles on the screen 7, for example. By optically designing the optical region 5, the light irradiation region can be freely controlled.

A configuration of the optical element 10 will be described. FIG. 3 is a diagram showing the configuration of the optical element 10. As shown in FIG. FIG. 3A is a perspective view of the optical element 10. FIG. FIG. 3(b) is a cross-sectional view of the optical element 10 taken along the line BB in FIG. 3(a). As shown in FIG. 3, the optical element 10 includes a substrate 11 and an optical functional layer 12. As shown in FIG.

The base material 11 is a member for supporting the optical function layer 12 . The substrate 11 may have optical transparency. The substrate 11 is made of, for example, quartz glass, soda glass, calcium fluoride, magnesium fluoride, barium borosilicate glass, aminoborosilicate glass, polycarbonate, polyethylene terephthalate, methyl-butadiene-styrene methacrylate copolymer, methyl-styrene methacrylate copolymer. Polymers, acrylic styrene copolymers, acrylonitrile butadiene styrene copolymers, and the like may also be used.
When used as a reflective optical element, the substrate 11 does not necessarily need to be light transmissive.

The shape of the substrate 11 is not particularly limited, but may be, for example, a rectangular parallelepiped. The dimensions of the substrate 11 may be, for example, 3 mm×3 mm×0.5 mm. In addition, the edge of the base material 11 may be chamfered. By chamfering the edge of the base material 11, the edge of the base material 11 can be prevented from being damaged when the base material 11 is transported or the like.

The optical function layer 12 is a layer for forming the optical region 5 . The optical function layer 12 is located on at least one surface of the substrate. The film thickness of the optical function layer 12 may be, for example, 20 μm. The optical function layer 12 may be formed by, for example, spin coating.

Although the optical function layer 12 is not particularly limited, it may be made of, for example, an ultraviolet curable resin. The ultraviolet curable resin may be a resin based on, for example, urethane acrylate, polyester acrylate, epoxy acrylate, polyether acrylate, polythiol, butadiene acrylate, or the like. By forming the optical function layer 12 with an ultraviolet curable resin, the optical regions 5 can be easily formed by an imprint method or the like.

Note that the optical function layer 12 may be made of, for example, a thermosetting resin or an electron beam curable resin. Also, the optical function layer 12 may be formed of thermosetting or ultraviolet curing spin-on glass.

An adhesion layer may be formed between the substrate 11 and the optical function layer 12 . The adhesion layer may be, for example, a silane coupling agent or the like. By forming the adhesion layer, adhesion between the substrate 11 and the optical function layer 12 can be improved. By improving the adhesion, when releasing the mold 8 from the optical function layer 12 in the imprint method, it is possible to suppress the separation between the base material 11 and the optical function layer 12 . Furthermore, when used as an optical element for a long period of time, improved adhesion is often advantageous.

The substrate 11 and the optical functional layer 12 may be combined into one layer as the optical functional substrate 13 . FIG. 4 is a diagram showing another configuration of the optical element 10. As shown in FIG. FIG. 4A is a perspective view of the optical element 10. FIG. FIG. 4(b) is a cross-sectional view of the optical element 10 taken along line CC in FIG. 4(a). As shown in FIG. 4 , the optical element 10 includes an optical functional substrate 13 .

The optical functional substrate 13 is a member for forming the optical region 5 . The optical function substrate 13 is a member that can maintain its shape independently. The optical functional substrate 13 may have optical transparency. Examples of the optical function substrate 13 include quartz glass, soda glass, calcium fluoride, magnesium fluoride, barium borosilicate glass, aminoborosilicate glass, polycarbonate, polyethylene terephthalate, methyl-butadiene-styrene copolymer methacrylate, and methacrylic acid. A methylstyrene copolymer, an acrylic styrene copolymer, an acrylonitrile-butadiene-styrene copolymer, or the like may also be used. The optical region 5 can be formed on the optical function base material 13 by, for example, an etching method, an injection molding method, or the like.
When used as a reflective optical element, the optical functional substrate 13 does not necessarily need to be light transmissive.

The shape of the optical function substrate 13 is not particularly limited, but may be, for example, a rectangular parallelepiped. The dimensions of the optical function substrate 13 may be, for example, 3 mm×3 mm×0.5 mm. The end of the optical functional substrate 13 may be chamfered. By chamfering the end portion of the optical function base material 13, it is possible to prevent the end portion of the optical function base material 13 from being damaged when the optical function base material 13 is transported or the like.

As shown in FIG. 3( a ), the optical function layer 12 has an optical region 5 and a first adhesive penetration suppression region 51A located on the outer periphery of the optical region 5 on the surface opposite to the side facing the base material 11 . have As shown in FIG. 4( a ), the optical functional substrate 13 has, on one surface, the optical region 5 and the first adhesive penetration suppression region 51A located on the outer periphery of the optical region 5 .

The optical region 5 is a region that exhibits an optical function with respect to incident light. The optical function may be a function based on light diffraction, refraction, or the like. As shown in FIGS. 3(b) and 4(b), the optical region 5 has an optical pattern 5A consisting of concave portions 5B and convex portions 5C. The recess 5B is a portion occupied by air. The convex portion 5C is a portion occupied by the material forming the optical function layer 12 or the optical function substrate 13 . The concave portion 5B and the convex portion 5C are made of substances having different refractive indices. Since there is an optical path difference between the light incident on the concave portion 5B and the light incident on the convex portion 5C, an optical function can be exhibited.

The optical pattern 5A is not limited to the two-level example shown in FIGS. 3(b) and 4(b), and may have three or more levels. FIG. 5 is a cross-sectional view in the z-direction of the optical region 5 consisting of the n-level optical pattern 5A. n is a natural number of 2 or more. The n level means that the maximum number of stages of the optical pattern 5A is n. As shown in FIG. 5, there may be optical patterns 5A with a number of steps less than n. The larger the value of n, the more accurately the light irradiation area can be controlled.

The optical pattern 5A may have a pattern in which the boundaries between the concave portions 5B and the convex portions 5C include curved lines when viewed from the optical axis of the incident light. FIG. 6 is a conceptual diagram showing the configuration of the optical pattern 5A in the optical region 5. As shown in FIG. The optical axis of incident light is the z-axis in FIG. The boundary between the concave portion 5B and the convex portion 5C is the interface between the air forming the concave portion 5B and the substance forming the convex portion 5C. A curve may be, for example, a wavy line, a polygonal line, or a combination thereof. Since the boundary between the concave portion 5B and the convex portion 5C includes a curved line, the light irradiation area can be controlled more accurately.

The optical region 5 may be a pattern in which unit cells 53 each having the same optical pattern 5A are arranged. A pattern in which the unit cells 53 are arranged is called a grating cell array type. The grating cell array type is sometimes called a grating cell array type or a GCA type. FIG. 7 is a conceptual diagram showing the configuration of the GCA-type optical region 5. As shown in FIG. FIG. 7 shows an example of a GCA-type optical region 5 in which nine unit cells 53 are arranged. The GCA-type optical regions 5 may be arranged in different directions for each unit cell 53 . By using the GCA-type optical region 5, the light irradiation region can be controlled more accurately.

The opening width of the concave portion 5B and the width of the convex portion 5C may be, for example, 0.1 μm or more and 20 μm or less on the upper surface of the optical function layer 12 or the optical function substrate 13 . The depth of the concave portion 5B, that is, the height of the convex portion 5C may be, for example, 0.1 μm or more and 3 μm or less. The pitch of the optical pattern 5A may be, for example, 0.2 μm or more and 40 μm or less.

The first adhesive permeation suppression region 51A is a region that suppresses permeation of the adhesive 4 into the optical pattern 5A. As shown in FIGS. 3(b) and 4(b), the first adhesive permeation suppression area 51A has a first adhesive permeation suppression pattern 6A consisting of grooves. The first adhesive permeation suppression pattern 6A is a pattern that suppresses permeation of the adhesive 4 into the optical pattern 5A. Since the first adhesive permeation suppression pattern 6A is formed of grooves, it has a resistance to permeation of the adhesive 4 and can suppress permeation of the adhesive 4 into the optical pattern 5A.

Let W0 be the opening width of the recessed portion 5B of the optical pattern 5A, D0 be the depth of the recessed portion 5B of the optical pattern 5A, W1 be the opening width of the first adhesive penetration suppression pattern 6A, and W1 be the aperture width of the first adhesive penetration suppression pattern 6A. If the depth is D1, (D1/W1) is greater than (D0/W0). In other words, the aspect ratio of the first adhesive permeation suppression pattern 6A is larger than the aspect ratio of the recesses 5B of the optical pattern 5A. Since the aspect ratio of the first adhesive permeation suppressing pattern 6A is larger than the aspect ratio of the concave portion 5B of the optical pattern 5A, the pressure of the air contained in the first adhesive permeation suppressing pattern 6A is increased, so that the advance of the adhesive 4 is suppressed. It can be stopped by the first adhesive permeation suppression pattern 6A. Therefore, it is possible to suppress the penetration of the adhesive 4 into the optical pattern 5A. As W1 becomes smaller, the number of the first adhesive permeation suppression patterns 6A arranged per unit area of the first adhesive permeation suppression region 51A increases, so the area of the first adhesive permeation suppression patterns 6A can be reduced.

FIG. 8 is an enlarged sectional view along the z-axis of the recess 5B of the optical pattern 5A and the first adhesive permeation suppression pattern 6A. FIG. 8(a) is a diagram of a form in which the optical pattern 5A has two levels. FIG. 8(b) is a diagram of a configuration in which the optical pattern 5A has four levels. The opening width W0 of the concave portion 5B of the optical pattern 5A is the width of the upper surface of the optical function layer 12 or the optical function base material 13 . Also, the depth D0 of the recess 5B of the optical pattern 5A is the depth from the upper surface of the optical function layer 12 or the optical function substrate 13 to the bottom surface of the recess 5B.

As shown in FIG. 8, the depth D0 of the concave portion 5B of the optical pattern 5A and the depth D1 of the first adhesive permeation suppression pattern 6A may be the same depth. When D0 and D1 have the same depth, the size relationship of the aspect ratio can be determined by the size relationship between the opening width W0 of the recess 5B of the optical pattern 5A and the opening width W1 of the first adhesive permeation suppression pattern 6A. Furthermore, since the optical pattern 5A and the first adhesive permeation suppression pattern 6A can be processed simultaneously, the process can be simplified.

The opening width W1 of the first adhesive permeation suppression pattern 6A may be, for example, 50 nm or more and 1 μm or less on the upper surface of the optical function layer 12 or the optical function substrate 13 . The depth D1 of the first adhesive permeation suppression pattern 6A may be, for example, 0.1 μm or more and 3 μm or less. The pitch of the first adhesive permeation suppression pattern 6A may be, for example, 0.1 μm or more and 2 μm or less. The pitch of the first adhesive permeation suppression pattern 6A may not be constant.

FIG. 9 is a diagram showing a form example of the first adhesive permeation suppression pattern 6A when viewed from the z-axis direction. As shown in FIG. 9A, the first adhesive permeation suppression pattern 6A may form a first flat curve L1 surrounding the optical region 5. As shown in FIG. Since the first adhesive permeation suppression pattern 6A forms the first flat curve L1 surrounding the optical region 5, the first adhesive permeation suppression pattern 6A is formed in all directions in which the adhesive 4 may permeate. Therefore, the effect of suppressing the penetration of the adhesive 4 into the optical pattern 5A is high. In addition, as shown in FIG.9(b), the shape of the 1st adhesive agent penetration|invasion suppression pattern 6A may be interrupted.

As shown in FIG. 9, the shape of the first adhesive permeation suppression pattern 6A may be the same shape as the shape of the frame 50 of the optical area 5 . The shape of the frame 50 may be square or circular, for example. The shape of the frame 50 is similar to a shape along the trajectory of lines perpendicular to the infiltration direction of the adhesive 4 . That is, since the adhesive 4 advances in the direction perpendicular to the direction in which the first adhesive permeation suppression pattern 6A extends, the effect of suppressing the permeation of the adhesive 4 into the optical pattern 5A is high.

The first closed curve L1 may be formed twice or more. Since the first closed curve L1 is formed in two or more layers, it is possible to have a plurality of boundary lines where the adhesive 4 stays, so that the penetration of the adhesive 4 into the optical pattern 5A can be strongly suppressed.

The first adhesive permeation suppression area 51A may have the mark 9 . FIG. 10 is a diagram showing an arrangement example of the marks 9. As shown in FIG. In FIG. 10, illustration of the first adhesive permeation suppression pattern 6A is omitted. As shown in FIG. 10, the marks 9 may be arranged at all or part of the four corners of the first adhesive permeation suppression area 51A. Also, the location and number of the marks 9 may be changed as appropriate. The mark 9 has a high degree of freedom in pattern shape, and can provide a sufficient difference in visibility from the first adhesive penetration suppression pattern 6A. Therefore, the mark 9 and the first adhesive penetration suppression pattern 6A are mixed. may Since the marks 9 are intermingled with the first adhesive permeation suppression pattern 6A, it is possible to maximize the freedom of design such as the arrangement and size of the first adhesive permeation suppression region 51A.

The marks 9 may be, for example, alignment marks, mold identification marks, position identification marks, defect marks, and the like. FIG. 11 is a diagram showing the form of the mark 9. As shown in FIG. FIGS. 11A to 11C are examples of alignment marks. FIG. 11(d) is an example of a type identification mark. FIG. 11(e) is an example of a position identification mark. FIG. 11(f) is an example of a defect identification mark.

Alignment marks are marks that improve the alignment accuracy when separate bodies are superimposed on each other. When the mark 9 is an alignment mark, highly accurate alignment between the optical element 10 and other objects is facilitated. Note that the mark 9 is not limited to the rectangular shape shown in FIGS. 11(a) to 11(c), and may have other planar shapes such as a cross shape and an L shape.

The mold identification mark is a mark for identifying the mold, and is written as "400A" in the example shown in FIG. 11(d). The mold identification mark is a code unique to the mold, and in the case of a multifaceted product, all the optical elements 10 have the same mark. Therefore, it is possible to determine with which mold the optical element 10 was molded.

A position identification mark is a mark that identifies the position of the optical element 10 in the mold. When molding a large number of optical elements 10 in one molding die, a position identification mark is provided as a code that can specify at which position the optical elements 10 are molded. The example in FIG. 11(e) shows an example in which "X25" is on the top and "Y34" is on the bottom, and is the 25th column in the X direction and the 34th row in the Y direction. It is shown that. Note that the display is not limited to the column number and row number as in this example, and numerical values starting from 1 may be used.

The mark 9 may be a combination of a type identification mark and a position identification mark so that one mark has both functions. For example, it may be "400A-X25Y34".

A defect identification mark is a mark formed with a predetermined size, and is provided for an inspector to refer to during visual inspection. Alternatively, it may be used as a criterion for automatic inspection by an inspection device. For example, even if an inspection standard is set such that a defect larger than 40 μm is regarded as a defective product, it is difficult for an inspector to determine the size of the defect. In addition, it is also difficult to unify judgment criteria for each inspector. Therefore, it is possible to improve the inspection pass/fail determination accuracy and the inspection takt time by making it possible to observe a portion that may be defective by comparing the defect identification marks.

In the example of FIG. 11(f), three defect identification marks having different dimensions are arranged in order of size. By arranging the defect identification marks whose dimensions gradually change at a constant rate, when an inspector observes a possible defect, it is expected that the size of the defect can be grasped quickly and accurately. Also, the defect identification mark is not limited to a square, and may be rectangular, circular, elliptical, or the like.

FIG. 12 is a diagram showing the configuration of the optical region 5. As shown in FIG. As shown in FIG. 12, the optical area 5 has a frame 50, a second adhesive penetration suppression area 51B, and a center area 52. As shown in FIG. A frame 50 is a line that forms the outline of the optical area 5 . The shape of the frame 50 is not particularly limited, but may be, for example, a square, a circle, or the like.

The second adhesive permeation suppression region 51B is a region for forming the second adhesive permeation suppression pattern 6B. The second adhesive permeation suppression area 51B is an area that fills a range of distances larger than 0 μm and smaller than 150 μm from the frame 50 toward the inside. The second adhesive permeation suppressing pattern 6B can be formed in the vicinity of the frame 50 by setting the second adhesive permeation suppressing region 51B to a range of distance greater than 0 μm. Further, by setting the distance of the second adhesive permeation suppression area 51B to a range smaller than 150 μm, a sufficient range for providing the second adhesive permeation suppression pattern 6B can be secured. In addition, light leakage from the outside of the optical region 5 can be sufficiently suppressed even when an alignment error in the xy direction between the light source 3 and the optical region 5 is taken into account. The shape of the second adhesive permeation suppression area 51B is determined due to the shape of the frame 50 .

The center region 52 is a region where the second adhesive permeation suppression pattern 6B is not formed. The center region 52 is a region surrounded by the second adhesive permeation suppression region 51B. The shape of the central region 52 is determined by the shapes of the frame 50 and the second adhesive permeation suppression region 51B.

The second adhesive permeation suppression area 51B has a second adhesive permeation suppression pattern 6B positioned in the recess 5B of the optical area 5 and forming a second closed curve L2 continuous with the protrusion 5C of the optical area 5 .

The second adhesive permeation suppression pattern 6B is a pattern having a function of blocking the adhesive 4 . FIG. 13 is a diagram showing the configuration of the second adhesive permeation suppression pattern 6B. The second adhesive permeation suppression pattern 6B is positioned in the recess 5B and forms a second closed curve L2 that is continuous with the protrusion 5C. A closed curve is a curve whose starting and ending points coincide. Continuity is the state of being connected one after another. As shown in FIG. 13, the second closed curve L2 is formed by connecting the second adhesive permeation suppression pattern 6B and the convex portion 5C continuous with the second adhesive permeation suppression pattern 6B.

FIG. 13(a) is a diagram showing the optical region 5 and the second adhesive permeation suppression pattern 6B. By positioning the second adhesive permeation suppression pattern 6B in the recess 5B, the permeation of the adhesive 4 into the optical region 5 is suppressed more strongly than when only the first adhesive permeation suppression pattern 6A is formed. can. Moreover, since it is not necessary to form the adhesive penetration suppression pattern 6 outside the optical region 5, 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 permeation suppression pattern 6 is positioned in the concave portion 5B, the outline of the convex portion 5C can be partially left, and loss of the optical function of the optical region 5 can be suppressed. Then, the second adhesive permeation suppression pattern 6B forms a second closed curve L2 that is continuous with the convex portion 5C, so that the permeation of the adhesive 4 into the optical region 5 can be suppressed. Therefore, loss of the optical function of the optical region 5 can be suppressed.

A second closed curve L2 is formed in the second adhesive permeation suppression region 51B so as to surround the center region 52. As shown in FIG. FIG. 13(b) is a diagram in which only the portion forming the second closed curve L2 is extracted from FIG. 13(a), and the second adhesive permeation suppression region 51B and the center region 52 are superimposed. The second adhesive permeation suppression pattern 6B can be formed in the vicinity of the frame 50 by forming the second closed curve L2 in the second adhesive permeation suppression region 51B so as to surround the central region 52 . Therefore, it is possible to suppress the incident light from irradiating the second adhesive permeation suppression pattern 6B.

The width of the second adhesive permeation suppression pattern 6B may be, for example, 0.1 μm or more and 20 μm or less. The height of the second adhesive permeation suppression pattern 6B may be, for example, 0.1 μm or more and 3 μm or less. The top surface of the second adhesive permeation suppression pattern 6B may be the same height as the top surface of the optical pattern 5A. Since the upper surface of the second adhesive permeation suppression pattern 6B and the upper surface of the optical pattern 5A are at the same height, the permeation of the adhesive 4 into the optical region 5 can be suppressed more strongly.

The second closed curve L2 may have an irregular shape. Irregular means not having a regular shape such as a square or a circle, for example. In the example shown in FIG. 13(a), the second closed curve L2 has an irregular shape. Due to the irregular shape of the second closed curve L2, the diffraction direction of the light irradiated to each of the second adhesive permeation suppression patterns 6B becomes irregular, making the second adhesive permeation suppression patterns 6B invisible. can do. Therefore, it is possible to suppress the specification of the position of the second adhesive permeation suppression pattern 6B.

The second closed curve L2 may have a regular shape such as a square or a circle. FIG. 14 is a diagram showing the configuration of the regular-shaped second closed curve L2. FIG. 14(a) is a diagram showing the configuration of the quadrangular second closed curve L2. FIG. 14(b) is a diagram showing the configuration of the circular second closed curve L2. The regular shape of the second closed curve L2 simplifies the design of the second adhesive permeation suppression pattern 6B. Therefore, the design time of the second adhesive permeation suppression pattern 6B can be shortened.

The second closed curve L2 may be formed twice or more. FIG. 15 is a diagram showing the configuration of the second closed curve L2 formed doubly. FIG. 15(a) is a diagram showing the configuration of the irregularly shaped second closed curve L2 formed doubly. FIG. 15(b) is a diagram showing the configuration of the regular-shaped second closed curve L2 that is formed doubly. Since the second closed curve L2 is formed in two or more layers, the penetration of the adhesive 4 into the optical region 5 can be suppressed more strongly.

FIG. 16 is a diagram showing the pitch P of the two second adhesive permeation suppression patterns 6B that face each other in parallel. The pitch P is the distance between the corresponding side surfaces of the two second adhesive permeation suppression patterns 6B facing each other in parallel when the second closed curve L2 is formed in two or more.

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

Further, when the phase difference between the pattern portion and the air portion is 180° at the air interface of the two-level optical element, the following formula (2) holds.

however,
P: pitch λ: wavelength of incident light θ: diffraction angle of light h: pattern height n: refractive index of pattern material.

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 on the same axis as the light before conversion. When the phase difference between the pattern portion and the air portion is 180°, the intensity of the 0th-order light becomes the minimum value. Are known.
For example, when the phase difference is 180° in a pattern material with a refractive index of 1.5, the wavelength λ of incident light and the pattern height h match according to Equation (2). However, the relationship between λ and h may change in a diffractive optical element where the intensity of the 0th order light is controlled to a constant level or the pattern material is not 1.5, so the present invention is limited to λ=h. do not have to

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, more preferably 0.4 or more and less than 1.0. The reason for this will be explained below.

The aspect ratio of the second adhesive permeation suppression pattern 6B is preferably 10 or less. For example, if the width of the second adhesive permeation suppression pattern 6B is d, the height of the second adhesive permeation suppression pattern 6B is preferably 10d or less. The wavelength λ of the incident light is preferably 10d or less because it preferably matches the height of the second adhesive permeation suppression pattern 6B. Since the pitch P is preferably twice the width of the second adhesive permeation suppression pattern 6B, it is 2d. That is, in order to set the aspect ratio of the second adhesive permeation suppression pattern 6B to 10 or less, the ratio P/λ must be 0.2 or more. By setting the ratio P/λ to be 0.2 or more, the aspect ratio of the second adhesive permeation suppression pattern 6B is 10 or less, so collapse of the second adhesive permeation suppression pattern 6B can be suppressed.

More preferably, the aspect ratio of the second adhesive permeation suppression pattern 6B is 5.0 or less. For example, if the width of the second adhesive permeation suppression pattern 6B is d, the height of the second adhesive permeation suppression pattern 6B is preferably 5.0 d or less. The wavelength λ of the incident light is preferably 5.0d or less because it preferably matches the height of the second adhesive permeation suppression pattern 6B. Since the pitch P is preferably twice the width of the second adhesive permeation suppression pattern 6B, it is 2d. That is, in order to set the aspect ratio of the second adhesive permeation suppression pattern 6B to 5.0 or less, the ratio P/λ must be 0.4 or more. By setting the ratio P/λ to be 0.4 or more, the aspect ratio of the second adhesive permeation suppression pattern 6B is 5.0 or less, so collapse of the second adhesive permeation suppression pattern 6B can be suppressed more strongly. .

The diffraction angle θ of light by the second adhesive permeation suppression pattern 6B is preferably 30° or more. That is, sin θ is preferably 0.5 or more. According to 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 set to 30° or more. For example, when the effective irradiation area provided by the optical region 5 is ±30°, which is the angle of view of a general camera, the diffracted light that becomes noise generated by the second adhesive permeation suppression pattern 6B is applied to the effective irradiation area. You can escape to the outside.

It is more preferable that the diffraction angle θ of light by the second adhesive permeation suppression pattern 6B is 45° or more. That is, sin θ is preferably 1/√2 or more. According to formula (1), the ratio P/λ is preferably 1.4 or less. By setting the ratio P/λ to 1.4 or less, the diffraction angle θ of light can be set to 45° or more. For example, when the effective irradiation area provided by the optical area 5 is ±30°, which is the angle of view of a general camera, the diffracted light that becomes noise generated by the second adhesive permeation suppression pattern 6B is more strongly effective. It can escape to the outside of the irradiation area.

More preferably, light is not diffracted by the second adhesive permeation suppression pattern 6B. sin θ is a value of 0 or more and 1.0 or less. If sin θ is greater than 1 in Equation (1), ie the ratio P/λ is less than 1.0, no light is diffracted. Therefore, even if the second adhesive permeation suppression pattern 6B is irradiated with incident light, diffraction of the light can be suppressed. Therefore, by setting the ratio P/λ to be less than 1.0, it is possible to suppress diffracted light that may be caused by the second adhesive permeation suppression pattern 6B and cause noise.

As described 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.

Like the optical function layer 12, the second adhesive permeation suppression pattern 6B may be made of an ultraviolet curable resin or the like. The optical pattern 5A and the second adhesive penetration suppression pattern 6B can be formed at the same time by forming the second adhesive penetration suppression pattern 6B from the ultraviolet curable resin. Therefore, the time for manufacturing the optical element 10 can be shortened.

The optical pattern 5A, the second adhesive permeation suppression pattern 6B, the first adhesive permeation suppression pattern 6A and the mark 9 may be formed by an imprint method. FIG. 17 is a diagram showing a method of manufacturing the optical element 10 by imprinting. As shown in FIG. 17(a), a substrate 11 is prepared. As shown in FIG. 17B, the uncured optical function layer 12 is formed by applying an ultraviolet curable resin on one surface of the substrate 11 . As shown in FIG. 17( c ), the concave-convex surface of the mold 8 is pressed against the surface of the optical function layer 12 opposite to the side facing the substrate 11 . The concave-convex surface of the mold 8 has patterns obtained by reversing the optical pattern 5A, the second adhesive penetration suppression pattern 6B, the first adhesive penetration suppression pattern 6A, and the mark 9. FIG. As shown in FIG. 17D, the optical functional layer 12 is cured by irradiating the optical functional layer 12 with ultraviolet rays UV from the back side of the mold 8 . As shown in FIG. 17E, the mold 8 is released from the optical function layer 12 to form the optical region 5 and the second adhesive permeation suppression pattern 6B on the optical function layer 12 . The optical element 10 is completed by a series of steps shown in FIG.

It is preferable that the mold 8 be made of a material or the like that transmits ultraviolet rays UV. As the mold 8, a master mold made of quartz glass or the like may be used. Moreover, as the mold 8, a resin replica mold reproduced from a master mold may be used.

The optical pattern 5A, the second adhesive permeation suppression pattern 6B, the first adhesive permeation suppression pattern 6A, and the mark 9 are not limited to the imprint method, and are formed by, for example, a lithography method such as photolithography or electron beam lithography. may

In the optical element 10 shown in FIG. 17E, the base material 11 may be etched using the optical function layer 12 as a mask. Since the optical region 5 and the second adhesive permeation suppression pattern 6B are formed on the substrate 11, the optical element 10 using the substrate 11 as the optical functional substrate 13 can be obtained.

FIG. 18 is a diagram showing a method of manufacturing the optical element 10 by etching. FIG. 18(a) is a diagram of the optical element 10 shown in FIG. 17(e) in which the substrate 11 is replaced by an optical functional substrate 13. FIG. As shown in FIG. 18B, an etching gas is used to anisotropically etch the optical function layer 12 and the optical function substrate 13 . Argon or the like may be used as the etching gas. By using argon as the etching gas, chemical reaction of the etching gas with the optical function layer 12 and the optical function substrate 13 can be suppressed. As shown in FIG. 18C, the optical element 10 is completed by removing the remaining film of the optical function layer 12 . When the optical function layer 12 is an ultraviolet curable resin, the remaining film of the optical function layer 12 may be removed by reactive ion etching using oxygen plasma or the like. When the optical function substrate 13 is quartz glass, the optical function substrate 13 is not etched by reactive ion etching using oxygen plasma, so only the remaining film of the optical function layer 12 can be removed.

A hard mask may be formed between the optical function layer 12 and the optical function substrate 13 . A metal such as chromium may be used as the hard mask. A hard mask is formed between the optical functional layer 12 and the optical functional substrate 13, so that the optical pattern 5A, the second adhesive penetration suppression pattern 6B, the first adhesive penetration suppression pattern 6A and the line edges of the mark 9 are formed. Roughness can be reduced.

EXAMPLES The present invention will be described in more detail with reference to examples below.

A pattern consisting of an optical pattern and a first adhesive permeation suppression pattern was designed. In the optical pattern, 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. The first adhesive permeation suppression pattern was formed by forming two rows of bundles each having a width of 300 nm, a pitch of 600 nm, and a depth of 1 μm.

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

A glass substrate having a thickness of 0.5 mm was prepared. An uncured UV curable resin was applied on a glass substrate in a film thickness of 20 μm. The mold was pressed against the UV curable resin. The ultraviolet curable resin was cured by irradiation with ultraviolet rays through the mold. By releasing the mold from the ultraviolet curable resin, the optical pattern and the first adhesive permeation suppression pattern were formed in the ultraviolet curable resin, and an optical element was obtained.

Isopropyl alcohol was dropped from the outside of the first adhesive permeation suppression pattern to the fabricated optical element. The state of isopropyl alcohol was observed.

FIG. 19 is a diagram showing how isopropyl alcohol is dropped from the outside of the first adhesive permeation suppression pattern. From FIG. 19, isopropyl alcohol was blocked by the first adhesive penetration suppression pattern, and the penetration of isopropyl alcohol into the optical pattern was suppressed.

1 Light irradiation device 10 Optical element 11 Base material 12 Optical function layer 13 Optical function base material 2 Holder 3 Light source 4 Adhesive 5 Optical region 50 Frame 51A First adhesive penetration suppression region 51B Second adhesive penetration suppression region 52 Central region 53 unit cell 5A optical pattern 5B concave portion 5C convex portion 6A first adhesive permeation suppression pattern 6B second adhesive permeation suppression pattern 7 screen 8 mold 8A pattern surface 8B back surface 9 mark S1 pre-conversion irradiation region S2 post-conversion irradiation region L1 1 closed curve L2 2nd closed curve P Pitch UV Ultraviolet

Claims (17)

a substrate;
an optical functional layer located on at least one surface of the base material;
The optical function layer has an optical region and a first adhesive penetration suppression region located on the outer periphery of the optical region on the surface opposite to the side facing the base material,
The optical region has an optical pattern consisting of recesses and protrusions,
The first adhesive penetration suppression area has a first adhesive penetration suppression pattern consisting of grooves,
Let W0 be the opening width of the concave portion of the optical pattern, D0 be the depth of the concave portion of the optical pattern, W1 be the opening width of the first adhesive penetration suppression pattern, and W1 be the aperture width of the first adhesive penetration suppression pattern. If the depth is D1, (D1/W1) is greater than (D0/W0),
optical element. An optical functional substrate having, on one surface, an optical region and a first adhesive penetration suppression region located on the outer periphery of the optical region,
The optical region has an optical pattern consisting of recesses and protrusions,
The first adhesive penetration suppression area has a first adhesive penetration suppression pattern consisting of grooves,
Let W0 be the opening width of the concave portion of the optical pattern, D0 be the depth of the concave portion of the optical pattern, W1 be the width of the first adhesive penetration suppression pattern, and W1 be the depth of the first adhesive penetration suppression pattern. D1, (D1/W1) is greater than (D0/W0),
optical element. The first adhesive penetration suppression pattern forms a first closed curve surrounding the optical region,
The optical element according to claim 1 or 2. The shape of the first closed curve is the same shape as the shape of the frame of the optical region,
The optical element according to claim 3. The first closed curve is formed in two or more,
The optical element according to claim 3 or 4. The first adhesive penetration suppression area has a mark,
The optical element according to any one of claims 1 to 5. The mark is a groove and is mixed with the first adhesive penetration suppression pattern,
The optical element according to claim 6. The optical region includes a frame, a second adhesive permeation suppression region that is a region that satisfies a range of a distance greater than 0 μm and less than 150 μm toward the inside from the frame, and a region surrounded by the second adhesive permeation suppression region. and a central region of
The second adhesive permeation suppression region has a second adhesive permeation suppression pattern that is positioned in the recess of the optical region and forms a second closed curve that is continuous with the protrusion of the optical region,
The second closed curve is formed to surround the central region,
The optical element according to any one of claims 1 to 7. The upper surface of the second adhesive permeation suppression pattern has the same height as the upper surface of the convex portion of the optical region,
The optical element according to claim 8. The second closed curve is formed in two or more,
The optical element according to claim 8 or 9. In the optical element according to claim 10,
The ratio of the pitch of the two second adhesive permeation suppression patterns facing in parallel with respect to the wavelength of the incident light is 0.2 or more and 2.0 or less.
optical element. In the optical element according to claim 10,
The ratio of the pitch of the two second adhesive permeation suppression patterns facing in parallel with respect to the wavelength of the incident light is 0.4 or more and 1.4 or less.
optical element. The second closed curve has an irregular shape,
13. The optical element according to any one of claims 8-12. The second adhesive penetration suppression pattern is composed of an ultraviolet curable resin,
14. The optical element according to any one of claims 8-13. The optical pattern has a pattern in which a boundary between the concave portion and the convex portion includes a curved line when viewed from the optical axis of incident light.
15. The optical element according to any one of claims 1-14. The optical pattern has a function of diffracting incident light,
16. The optical element according to any one of claims 1-15. A device comprising the optical element according to any one of claims 1 to 16,
Light irradiation device.

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