CN100541235C - Anti-reflection structure, anti-reflection molded body, manufacturing method thereof, and automobile part - Google Patents

Abstract

The invention discloses a kind of anti-reflection structure, comprise: with a plurality of bossings of the pitch arrangement shorter than the wavelength of luminous ray, each described bossing forms frustum basically and a kind of in the frusto-pyramidal basically, each described bossing comprises: i) form end circle and in be connected in this end circle end polygon the two one of basal surface, a) described end circle and b) circle of the polygonal described end of the external described end has the end diameter Db:100nm＜Db＜380nm that satisfies following formula separately, ii) form circle and in be connected to this in the circle last polygon the two one of upper surface, a) described circle and the b of going up) the external described polygonal described round last diameter Du:5nm＜Du＜50nm that satisfies following formula that has separately that.

Description

Anti-reflection structure, anti-reflection molded body, manufacturing method thereof, and automobile part

technical field

The present invention relates to an antireflection fine structure excellent in antireflection ability of light and anti-scratch. Furthermore, the present invention relates to an anti-reflection molded body having the above-mentioned anti-reflection microstructure, wherein the anti-reflection molded body is preferably used as a non-reflection panel for applications such as i) vehicles (including automobiles), boats, airplanes, etc. various instruments, ii) display devices, etc. Furthermore, the present invention relates to a method of manufacturing an antireflection molded body. Still further, the present invention relates to automobile parts having the above-mentioned anti-reflection fine structure.

Background technique

As images are input on the screens of various display devices such as liquid crystal displays, CRT displays, etc., depending on the specific situation, for a more practical example, the external light or internal illumination light input on the home TV screen will significantly reduce the visibility of the image.

Also, at a driver's seat of an automobile, a display portion in which various gauges such as a speedometer, an oil gauge, etc. are provided has a front surface in which a front cover of the gauge is fitted. Depending on the situation, the scene outside the vehicle that is input as an image on the display unit through the front window (windshield) or the side window degrades the visibility of various display devices. In this case, the meter cover is arranged on the display unit, thereby preventing external light from being projected onto the meter display.

A known structure for preventing the above-mentioned reflection of light includes a multilayer antireflection film including multilayer thin films having different refractive indices. However, Published Japanese Patent Application No. 2002-267815 discloses an antireflection structure employing a fine structure for further reducing reflectance than the above-mentioned multilayer antireflection film.

Published Japanese Patent Application No. 2002-267815 discloses an antireflection structure in which a large number of fine irregularities (protrusions and depressions) made of a transparent material are formed on the surface of a transparent molded article. Forming the intervals each smaller than or equal to the wavelength of light changes the refractive index of light in the thickness direction.

Contents of the invention

An object of the present invention is to provide an anti-reflection microstructure having i) a micro-irregular tip structure optimized so as to prevent damage to the micro-irregular tip without losing light anti-reflection properties, and ii) Anti-reflection and anti-scratch properties.

Another object of the present invention is to provide an antireflection molded body having the above-mentioned antireflection fine structure.

Still another object of the present invention is to provide a method of manufacturing an antireflection molded body.

A further object of the present invention is to provide an automobile part (such as a front cover of an instrument, a window glass, etc.) having the above-mentioned anti-reflection fine structure.

After excellent examination or research, the present inventors have found that the following strategies can achieve the above objects, thereby completing the present invention:

To the extent that anti-reflection properties are not adversely affected, the most vulnerable (i.e. most likely to be scratched) head end faces of the individual raised portions of the microirregularities are smoothed in such a way that the microirregularities Basically formed as a truncated cone or truncated pyramid.

According to a first aspect of the present invention, there is provided an antireflection structure comprising: a plurality of raised portions arranged at a pitch shorter than a wavelength of visible light, each of the raised portions being formed into a substantially frustoconical shape and one of substantially truncated pyramids, each of said raised portions comprising: i) a bottom surface formed as one of a base circle and a base polygon inscribed in the base circle, a) said base The circle and b) the base circle circumscribing the base polygon each have a base diameter Db satisfying the following expression: 100nm<Db<380nm, ii) formed as both an upper circle and an upper polygon inscribed in the upper circle One of the upper surfaces, a) the upper circle and b) the upper circle circumscribing the upper polygon each have an upper diameter Du satisfying the following expression: 5nm<Du<50nm, wherein each of the protrusions The part has a head end surface curved to define a radius of curvature R satisfying the following expression: R≥[{(Du ² −Du·Db)/(4·H)} ² +(Du/2) ² ] ^1/2 , where H represents the height of each raised portion.

Preferably, the bottom surfaces of the raised portions adjacent to each other are in contact with each other.

Preferably, each of the bottom surfaces is formed in any one of i) a non-oriented circle, ii) an equilateral triangle, iii) a rectangle, and iv) a regular hexagon.

According to a second aspect of the present invention, there is provided an anti-reflection molded body comprising an anti-reflection structure on at least one of its first surface and second surface, the anti-reflection structure comprising: a plurality of raised portions arranged at intervals, each of said raised portions being formed into one of a substantially frustoconical shape and a substantially frustopyramidal shape, each said raised portion comprising: i) formed as The bottom surface of either a bottom circle and a bottom polygon inscribed in the bottom circle, a) the bottom circle and b) the bottom circle circumscribing the bottom polygon each have a bottom diameter Db satisfying the following expression : 100nm<Db<380nm, ii) an upper surface formed as one of an upper circle and an upper polygon inscribed in the upper circle, a) the upper circle and b) the upper surface circumscribing the upper polygon The circles each have an upper diameter Du satisfying the following expression: 5nm<Du<50nm, wherein each of said raised portions has a head end face curved to define a radius of curvature R satisfying the following expression: R≥ [{(Du ² −Du·Db)/(4·H)} ² +(Du/2) ² ] ^1/2 , where H represents the height of each of the raised portions.

Preferably, the antireflection molding is substantially transparent.

According to a third aspect of the present invention, there is provided a method of manufacturing an anti-reflection molded body, comprising: I) preparing: A) a forming mold having an anti-reflection structure, the anti-reflection structure comprising: a plurality of raised portions arranged, each of said raised portions being formed into one of a substantially frustoconical shape and a substantially frustopyramidal shape, each said raised portion comprising: i) formed as a bottomed circle and the bottom surface of either of the bottom polygons inscribed in the bottom circle, a) the bottom circle and b) the bottom circle circumscribing the bottom polygon each have a base diameter Db satisfying the following expression: 100 nm <Db<380nm, ii) an upper surface formed as one of an upper circle and an upper polygon inscribed in the upper circle, a) the upper circle and b) the upper circle circumscribing the upper polygon are each have an upper diameter Du that satisfies the following expression: 5nm<Du<50nm, wherein each of the raised portions has a head end surface that is curved to define a radius of curvature R that satisfies the following expression: R≥[{ (Du ² -Du·Db)/(4·H)} ² +(Du/2) ² ] ^1/2 , where H represents the height of each of the raised portions, and B) for the anti-reflection the base of the molded body; II) pressing the forming die and the base against each other in a state where at least one of the forming die and the base is heated; and III) on the first surface of the base The anti-reflection structure is formed on at least one of the second surface and the second surface.

According to a fourth aspect of the present invention, there is provided a method of manufacturing an anti-reflection molded body, comprising I) preparing: A) a forming mold having an anti-reflection structure, the anti-reflection structure comprising: a plurality of raised portions, each of which is formed as one of a substantially truncated cone and a substantially truncated pyramid, each of said raised portions comprising: i) formed as a base circle and The bottom surface of either of the bottom polygons inscribed in the bottom circle, a) the bottom circle and b) the bottom circle circumscribing the bottom polygon each have a base diameter Db satisfying the following expression: 100 nm<Db<380nm, ii) an upper surface formed as one of an upper circle and an upper polygon inscribed in the upper circle, a) the upper circle and b) the upper circle circumscribing the upper polygon each have An upper diameter Du satisfying the following expression: 5nm<Du<50nm, wherein each of the raised portions has a head end face curved to define a radius of curvature R satisfying the following expression: R≥[{( Du ² −Du·Db)/(4·H)} ² +(Du/2) ² ] ^1/2 , where H represents the height of each of the raised portions, and B) is used for the anti-reflection mode the base of the body; II) irradiating active energy to the forming die and the base with an active energy ray-curable resin disposed between the forming die and the base; and III) The antireflection structure is formed on at least one of the first surface and the second surface.

According to a fifth aspect of the present invention, there is provided an automobile part comprising an anti-reflection structure comprising: a plurality of raised portions arranged at intervals shorter than the wavelength of visible rays, each of the raised portions being formed as one of substantially frustoconical and substantially frustopyramidal, each of said raised portions comprising: i) a base formed as one of a base circle and a base polygon inscribed in the base circle On the surface, a) the base circle and b) the base circle circumscribing the base polygon each have a base diameter Db satisfying the following expression: 100nm<Db<380nm, ii) formed as an upper circle and inscribed on the upper circle The upper surface of either of the upper polygons in the circle, a) the upper circle and b) the upper circle circumscribing the upper polygon each have an upper diameter Du satisfying the following expression: 5nm<Du<50nm, where , each of said convex portions has a head end surface curved to define a radius of curvature R satisfying the following expression: R≥[{(Du ² −Du·Db)/(4·H)} ² + (Du/2) ² ] ^1/2 , where H represents the height of each of the raised portions.

Description of drawings

Other objects and features of the present invention will be understood from the following description made with reference to the accompanying drawings.

FIG. 1A is a perspective view of an antireflection microstructure according to the present invention, and FIG. 1B is a perspective view of an antireflection molded body having an antireflection microstructure according to the present invention.

FIG. 2A shows the measurement positions of the fine convex portions of the antireflection fine structure formed as a truncated cone.

FIG. 2B shows the measurement positions of the fine convex portions of the antireflection fine structure formed as a truncated pyramid.

FIG. 3 is a graph showing the upper diameter Du of the fine convex portion of the anti-reflection microstructure versus the average reflectance.

4A , 4B and 4C illustrate schematic structures of different forms of the head end faces of the fine protrusions of the anti-reflection microstructures.

5A and 5B show that the structures of the ridge lines of the fine raised portions of the anti-reflection microstructure according to the present invention are represented by the corresponding n-time linear expressions [1] and [2].

Detailed ways

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

For ease of understanding, the following descriptions contain various directional terms, such as left, right, up, down, front, back, etc. However, such terms should be understood only with reference to the drawings in which corresponding parts of the elements are shown.

Furthermore, unless otherwise stated hereinafter, the term "cone" means a circular cone, to be distinguished from the term "pyramid", while the term "frustum" means a circular frustum, to be distinguished from the term " Truncated pyramids" are distinguished.

Explained later in detail according to the present invention include the antireflection microstructure, the antireflection molded body on which the antireflection microstructure is applied, the manufacturing method of the antireflection molded body, examples (including comparative examples) of the above, and the like.

The antireflection fine structure according to the present invention includes a large number of fine raised portions each formed into a truncated pyramid or a truncated pyramid. The fine raised portions are arranged at a pitch smaller than the wavelength of visible rays, and the bottom surface and the upper surface of the fine raised portions are formed in circular or polygonal shapes each having a specific size.

FIG. 1 is a perspective view of an antireflection fine structure 1 according to an embodiment of the present invention, and FIG. 1B is a perspective view of an antireflection molded body 10 (described later) having an antireflection fine structure 1 . The anti-reflection fine structure 1 of the present invention has such a structure that the head end face 1pe is formed on a frustum of a pyramid 5 or a frustum of a pyramid 6 (in FIG. The convex portions 1p are arranged at a pitch 4 shorter than the wavelength of visible rays.

Therefore, in the thickness direction, the light refraction index at each cross section is determined by the occupancy ratio of each step surface in the thickness direction of the antireflection fine structure 1 (raw material of the antireflection fine structure 1 with respect to air) It is determined that the refractive index of the air changes continuously from the refractive index of the material, thereby producing the anti-reflection property of light. At the same time, the head end surface 1pe of each finely raised portion 1p is flattened within a numerical range described later. Therefore, even if the anti-reflection microstructure 1 rubs or collides with other component materials, it is less likely to be damaged or scratched, satisfies light anti-reflection and anti-scratch properties, and minimizes harmful effects on anti-reflection properties.

FIG. 2A shows the dimensions of the finely raised portion 1 p of the frustum 5 . The bottom diameter Db of the bottom circle 2bc of the bottom surface 2 and the upper diameter Du of the upper circle 3uc of the upper surface 3 satisfy 100nm<Db<380nm and 5nm<Du<50nm, respectively.

Furthermore, FIG. 2B shows the dimensions of the finely raised portion 1p of the truncated pyramid 6, typically a quadrangular truncated pyramid 6. Similarly, the bottom diameter Db of the circumscribed circle (i.e. bottom circle 2bc) of the bottom polygon 2bp of the bottom surface 2 and the upper diameter Du of the circumscribed circle (i.e. the upper circle 3uc) of the upper polygon 3up of the upper surface 3 respectively satisfy 100nm<Db<380nm and 5nm<Du<50nm.

That is, the base diameter Db greater than or equal to 380nm, where 380nm is the distance between visible rays, cannot make the interval 4 between adjacent fine convex portions 1p shorter than the wavelength of visible rays, resulting in light diffraction and thereby lowering the antireflection capability. shortest wavelength.

Meanwhile, the lower limit of the bottom diameter Db will be explained. In order to obtain the anti-reflection capability, by inclining the side faces of the fine convex portion 1p to a certain degree, the light refractive index is continuously changed in the cross-section in the thickness direction. Thus, in view of the upper limit of 50 nm of the upper diameter Du of the upper surface 3 (described in detail later), the bottom diameter Db of 100 nm or less cannot produce sufficient anti-reflection capability due to insufficient side slope.

FIG. 3 is a graph showing the correspondence between the upper diameter Du of the upper surface 3 of each fine convex portion 1p of the antireflection microstructure 1 and the average reflectance. The larger the upper diameter Du, the more the planar ratio increases, resulting in higher reflectivity. However, as is evident from FIG. 3 , the upper diameter Du greater than or equal to 50 nm causes a rapid increase in reflectance. However, in the range smaller than 50 nm, the graph is substantially similar to the case without leveling (Du=0). Thus, the upper diameter Du of the upper surface 3 of the fine convex portion 1p is set to be smaller than 50 nm.

However, in the above-mentioned antireflection fine structure 1, it is extremely difficult to mold an upper diameter Du smaller than or equal to 5 nm as a lower limit even by electron beam lithography or the like.

Also, in order to further reduce the reflectivity, the upper surface 3 (head end surface 1pe) of the above-mentioned fine convex portion 1p is preferably a curved surface such as a dome shape in FIG. 4A rather than a flat surface. The curvature radius R of the above-mentioned curved surface preferably satisfies the following expression [X], where H represents the height of the fine convex portion 1p.

R≥[{(Du ² -Du·Db)/(4·H)} ² +(Du/2) ² ] ^1/2 ·····[X]

That is, the right side of the above expression [X] represents the length of the perpendicular from the normal (the center point of the circumscribed circle passing through the bottom surface 2) to the ridge line 12 at the tip of the antireflection microstructure 1, expressed as In other words, the length of the perpendicular represents the radius of curvature of the end face 1pe of the head. The radius R of curvature R of the head end surface 1pe of the finely raised portion 1p being less than or equal to the value thus calculated makes the tip sharp, depending on the case, resulting in a scratch-causing hook.

Here, if the head end surface 1pe is in (included) in the dome curved surface having the above-mentioned radius of curvature R, the structure of the head end surface 1pe of the fine convex portion 1p can be variable (amorphous), as shown in FIG. 4B and 4C.

The structure of the fine raised portion 1p of the present invention is, as mentioned above, a truncated pyramid or a truncated pyramid. In this case, however, the structure is not necessarily limited to a precise frustum or a precise frustum of a pyramid, that is, the generatrix of the frustum of the cone or the ridge 12 of the frustum of the pyramid are not limited to straight , but can be curved. The busbars or ridges 12 are preferably curved, satisfying the following n-sublinear expressions [1] and [2]. Thereby, the change in the refractive index in the thickness direction of the antireflection fine structure 1 becomes more gentle, thereby reducing the light reflectance more effectively. Here, the n-times of the linear expressions [1] and [2] are preferably in the range greater than 1 and less than or equal to 3.

Refer to FIG. 5A or FIG. 5B to elaborate the above content in more detail. In a vertical section through the center of the fine raised portion 1p, with the bottom side defined as the X axis and the apex 11 disposed on the Z axis, i) the height of each fine raised portion 1p of the antireflection fine structure 1 H, ii) the height Ha to the apex 11, which is defined by the extension of the ridge line 12 of the fine raised portion 1p, and iii) the base diameter Db of the base circle 2bc of the bottom surface 2 or the base polygon circumscribing the bottom surface 2 The base diameter Db of the base circle 2bc of 2bp, combined, gives the X-coordinate on the ridge 12 expressed by one of the following n-time linear expressions [1] and [2]:

X=(Db/2)×{1-(Z/Ha) ⁿ }·····[1] See Figure 5A

Z={Ha/(Db/2) ⁿ }×X ⁿ [2] See Figure 5B

In the above, when the vertex 11 is set at a certain position, a constant term for correction can be added.

Also, from the viewpoint of further reducing the reflectance by reducing the flat portion between the fine raised portions 1p, the structure of the bottom surface 2 of the fine raised portions 1p is preferably such that the bottoms of the adjacent fine raised portions 1p The surfaces 2 are in contact with each other without separation.

From the above viewpoint, i) non-oriented circles, ii) equilateral triangles, iii) rectangles, and iv) regular hexagons that can be arranged on a plane without gaps are preferable.

The above-mentioned antireflection microstructure 1 of the present invention is molded onto a substrate 15, typically molded onto the first surface 15A of the transparent substrate 15, or preferably molded onto both surfaces of the substrate (the first surface 15A and the second surface 15A). The anti-reflection molded body 10 can be formed on the two surfaces 15B). Applying the above-mentioned anti-reflection molded body 10 to panels of various display devices, transparent panels such as display windows or display cabinets, etc., can reduce the reflection of external light or indoor lighting, and effectively prevent built-in imaging of reflected images, thereby Improved visibility of graphics, displays and interior displays.

Moreover, the above-mentioned antireflection fine structure 1 (antireflection molded body 10) is applied to various parts such as automobile parts, especially glass of windows or roofs, bezels, headlights, rear finishers, The same anti-reflection effect can be produced in a film or the like used for the front surface of a display device such as a liquid crystal or the like.

A method of manufacturing the antireflection molded body 10 according to the present invention will be described below. A forming die having the aforementioned large number of finely raised portions 1p was prepared. Subsequently, the forming die and the base 15 are relatively pressed against each other in a state where at least one of the forming die and the base 15 is heated. Thus, the antireflection fine structure 1 is formed on at least one of the first surface 15A and the second surface 15B of the substrate 15 .

Alternatively, active energy ray (active energy line) is irradiated to the forming mold and the base 15 with the active energy ray curable resin disposed therebetween, followed by solidification (hardening) of the active energy ray curable resin, whereby the base 15 The antireflection microstructure 1 is formed on at least one of the first surface 15A and the second surface 15B, thereby forming the antireflection molded body 10 .

Preferably, typical materials for the above-mentioned substrate 15 are those having transparency, in particular, i) thermoplastic resins such as methyl methacrylate, polymethyl acrylate, polyethylene, polypropylene, polyvinyl alcohol, poly Vinylidene chloride, polyethylene terephthalate, polyvinyl chloride, polystyrene, ABS resin, AS resin, acrylic resin, polyamide, polyacetal, polybutylene terephthalate ), glass-reinforced polyethylene terephthalate, polycarbonate, modified polyphenylene ether, polyphenylene sulfide, polyether ether ketone, liquid crystal polymer, fluororesin, polyallate, poly Sulfone, polyethersulfone, polyamide-imide, polyetherimide, thermoplastic polyimide, etc., ii) thermosetting resins such as phenolic resins, melamine resins, urea resins, epoxy resins, not Saturated polyester resin, alkyd resin, silicone resin, diallyl phthalate resin, polyamide bismaleimide, polyamide triazole, etc., and iii) two or more of the above materials combination of materials.

Also, examples of active energy ray-curable resins that initiate polymerization by irradiation such as ultraviolet rays and are subsequently solidified (cured) include: i) ultraviolet-curable acryl urethaneresin, ultraviolet-curable methyl methacrylate, ultraviolet-curable polyacrylic acid Methyl ester, UV curable polyester acrylate resin, UV curable epoxy acrylate resin, UV curable polyol acrylate resin, UV curable epoxy resin, etc. A polymerization initiator that causes radicals by irradiating active energy rays may be used when necessary. Also, a coagulating agent (curing agent, hardener) such as isocyanate may be added to further enhance coagulation. Typical examples of active energy rays used here include ultraviolet rays, X-rays, other electron beams, other electromagnetic waves, etc., but are not specifically limited to these.

Also, an inorganic transparent material such as glass may also be used for the substrate 15 . In this case, by a method such as i) cutting the surface of the glass with an electron beam, etc., and ii) pouring the melted inorganic transparent material into the mold having the antireflection fine structure 1 of the present invention, it can be formed on the surface of the substrate 15. Anti-reflection microstructures 1 are formed on at least one of the first surface 15A and the second surface 15B.

In the above-mentioned latter method, after pouring the melted inorganic transparent material, if necessary, before the above-mentioned material is cooled, a second mold having the same anti-reflection structure is pressed against, so that the first surface 15A of the substrate 15 and the first surface 15A of the base 15 and The anti-reflection fine structure 1 is formed on the second surface 15B. In addition, if necessary, the inorganic transparent material whose two surfaces are pressed against by the mold is heated to a softening point, and then pressure is applied to transfer the structure, to thereby be printed on the first surface 15A and the second surface 15B of the substrate 15 An anti-reflection fine structure 1 is formed.

example

Hereinafter, the present invention will be described more specifically based on the following examples. However, the present invention is not limited to these examples.

(first instance)

The mold formed by a commercially available electron beam drawing device is heated to 150°C. Subsequently, the mold was pressed against both faces (the first surface 15A and the second surface 15B) of the polymethylmethacrylate substrate 15 under a pressure of 10 MPa for 1 hour, and then cooled to 70° C. or less to The anti-reflection molded body 10 in which both surfaces (the first surface 15A and the second surface 15B) are provided with the anti-reflection microstructure 1 is thus formed, wherein each fine raised portion 1p encloses the spliced state in a hexagonal shape Set (pitch 4: 200nm). Each fine raised portion 1p is formed as a truncated cone having a bottom surface 2 with a base diameter Db of 200 nm, an upper surface 3 with an upper diameter Du of 20 nm, a height H of 400 nm, and a radius of curvature R (at the head) of 10.25 nm. end face 1pe).

(second instance)

The same operation as that of the above-mentioned first example is carried out using a mold formed by the same electron beam drawing apparatus, to thereby form a , Antireflection molded body 10 including polymethyl methacrylate base 15 in which fine raised portions 1 p are arranged in a hexagonal closest fit (pitch 4: 250 nm). Each fine convex portion 1p is formed as a truncated cone having a bottom surface 2 with a base diameter Db of 250nm, an upper surface 3 with an upper diameter Du of 25nm, a height H of 250nm, and a head end surface 1pe that is flat.

(third instance)

The same operation as that of the above-mentioned first example is carried out using a mold formed by the same electron beam drawing apparatus, to thereby form a , Antireflection molded body 10 including polymethyl methacrylate base 15 in which fine raised portions 1 p are arranged in a hexagonal closest fit (pitch 4: 250 nm). Each fine raised portion 1p is formed as a truncated cone having a bottom surface 2 with a base diameter Db of 250 nm, an upper surface 3 with an upper diameter Du of 25 nm, a height H of 250 nm, and a radius of curvature R (at the head) of 13.71 nm. end face 1pe).

(fourth instance)

The same operation as that of the above-mentioned first example is carried out using a mold formed by the same electron beam drawing apparatus, to thereby form a , Antireflection molded body 10 including polymethyl methacrylate base 15 in which each fine raised portion 1p is arranged in a hexagonal most closely packed state (pitch 4: 177 nm). Each fine raised portion 1p is formed as a truncated rectangular pyramid, having a bottom surface 2 with a base diameter Db of 250 nm (circle circumscribed in a rectangle), and an upper surface 3 with an upper diameter Du of 50 nm (circle circumscribed in a rectangle) of 500 nm. Height H, and a radius of curvature R of 25.50 nm (at the end face 1pe of the head).

(Fifth example)

The operation as in the above-mentioned first example was carried out using a mold formed by the same electron beam drawing apparatus, to thereby form a polymethylmethacrylate-comprising substrate provided with anti-reflection fine structures 1 on the back side (second surface 15B) 15. The antireflection molded body 10 in which the fine convex portions 1p are arranged in a hexagonal closest fit (pitch 4: 300 nm). Each fine raised portion 1p is formed as a truncated cone having a bottom surface 2 with a base diameter Db of 300 nm, an upper surface 3 with an upper diameter Du of 50 nm, a height H of 600 nm, and a radius of curvature R (at the head) of 25.54 nm. end face 1pe).

(sixth example)

The same operation as that of the above-mentioned first example is carried out using a mold formed by the same electron beam drawing apparatus, to thereby form a , Antireflection molded body 10 including polymethyl methacrylate base 15 in which each fine raised portion 1p is arranged in a hexagonal most closely packed state (pitch 4: 177 nm). Each fine raised portion 1p is formed as a truncated rectangular pyramid, having a bottom surface 2 with a base diameter Db of 250 nm (circle circumscribed in a rectangle), and an upper surface 3 with an upper diameter Du of 30 nm (circle circumscribed in a rectangle) of 640 nm. The height Ha (to the apex 11), the height H of 550nm, and the head end face 1pe are flat. In each fine convex portion 1p, the ridge line 12 extending from the peripheral portion of the head end surface 1pe to the peripheral portion of the bottom surface 2 is given by the following linear expression [1] having degree n=1.2.

X＝(Db/2)×{1-(Z/Ha) ⁿ }·····[1]

(seventh example)

The same operation as that of the above-mentioned first example is carried out using a mold formed by the same electron beam drawing apparatus, to thereby form a , Antireflection molded body 10 including polymethyl methacrylate base 15 in which each fine raised portion 1p is arranged in a hexagonal most closely packed state (pitch 4: 177 nm). Each fine raised portion 1p is formed as a truncated rectangular pyramid, having a bottom surface 2 with a base diameter Db of 250 nm (circle circumscribed in a rectangle), an upper surface 3 with an upper diameter Du of 50 nm (circle circumscribed in a rectangle), and an upper surface 3 of 720 nm. Height Ha (to apex 11), height H of 550 nm, and radius of curvature R of 50 nm (at head end face 1pe). In each fine convex portion 1p, the ridge line 12 extending from the peripheral portion of the head end surface 1pe to the peripheral portion of the bottom surface 2 is given by the linear expression [1] having degree n=1.2.

(eighth example)

The same operation as that of the above-mentioned first example is carried out using a mold formed by the same electron beam drawing apparatus, to thereby form a , Antireflection molded body 10 comprising polymethyl methacrylate base 15 in which fine raised portions 1 p are arranged in a hexagonal closest fit (pitch 4: 212 nm). Each fine raised portion 1p is formed as a truncated rectangular pyramid, having a bottom surface 2 with a base diameter Db of 300 nm (circle circumscribed in a rectangle), an upper surface 3 with an upper diameter Du of 40 nm (circle circumscribed in a rectangle), and an upper surface 3 of 400 nm. Height Ha (to apex 11), height H of 300 nm, and radius of curvature R of 45 nm (at head end face 1 pe). In each fine convex portion 1p, the ridge line 12 extending from the outer peripheral portion of the head end surface 1pe to the outer peripheral portion of the bottom surface 2 is given by the following linear expression [2] with degree n=2:

Z＝{Ha/(Db/2) ⁿ }×X ⁿ ·····[2]

(ninth example)

The same operation as that of the above-mentioned first example is carried out using a mold formed by the same electron beam drawing apparatus, to thereby form a , Antireflection molded body 10 comprising polymethyl methacrylate base 15 in which each fine raised portion 1p is arranged in a hexagonal most closely packed state (pitch 4: 141 nm). Each fine raised portion 1p is formed as a truncated rectangular pyramid, having a bottom surface 2 with a base diameter Db of 200 nm (circle circumscribing the rectangle) and an upper surface 3 with an upper diameter Du of 10 nm (circle circumscribing the rectangle) of 555 nm. Height Ha (to apex 11), height H of 500nm, and radius of curvature R of 15nm (at head end face 1pe). In each fine convex portion 1p, the ridge line 12 extending from the peripheral portion of the head end surface 1pe to the peripheral portion of the bottom surface 2 is given by a linear expression [2] having degree n=2.

(first comparative example)

The same operation as that of the above-mentioned first example is carried out using a mold formed by the same electron beam drawing apparatus, to thereby form a , Antireflection molded body 10 including polymethyl methacrylate base 15 in which fine raised portions 1 p are arranged in a hexagonal closest fit (pitch 4: 250 nm). Each fine raised portion 1p is formed into a cone having a bottom surface 2 having a bottom diameter Db of 250 nm and a height H of 750 nm.

(second comparative example)

The same operation as that of the above-mentioned first example is carried out using a mold formed by the same electron beam drawing apparatus, to thereby form a , Antireflection molded body 10 comprising polymethyl methacrylate base 15 in which fine raised portions 1p are arranged in a hexagonal closest fit (pitch 4: 400 nm). Each fine raised portion 1p is formed as a truncated cone having a bottom surface 2 with a base diameter Db of 400 nm, an upper surface 3 with an upper diameter Du of 25 nm, a height H of 800 nm, and a radius of curvature R (at the head) of 12.84 nm. end face 1pe).

(Third comparative example)

The same operation as that of the above-mentioned first example is carried out using a mold formed by the same electron beam drawing apparatus, to thereby form a , Antireflection molded body 10 including polymethyl methacrylate base 15 in which fine raised portions 1 p are arranged in a hexagonal closest fit (pitch 4: 250 nm). Each fine raised portion 1p is formed as a truncated cone having a bottom surface 2 with a base diameter Db of 250 nm, an upper surface 3 with an upper diameter Du of 100 nm, a height H of 500 nm, and a radius of curvature R (at the head) of 50.56 nm. end face 1pe).

[Evaluation test method]

The above-mentioned antireflection molded bodies 10 obtained by the above-mentioned Examples and Comparative Examples were subjected to the following evaluation tests in terms of average reflectance and scratch resistance. Table 1 shows the evaluation test results and the specifications of each antireflection molded body 10 .

(1) Average reflectance measurement

A variable angle spectrophotometer (manufactured by Otsuka Electronics Co., Ltd.) was used to measure the reflectance of each antireflection molded body 10 under the condition that the light incident angle was 0 and the measurement angle was 0. Measurements were performed at stepwise wavelengths (10 nm) from 380 nm to 780 nm. The average value of the measurement results is defined as the average reflectance.

(2) Anti-scratch test

According to the pencil hardness test specified in JIS K5600-5-4 (where JIS stands for Japanese Industrial Standard), an HB pencil is used to scratch the test specimen with a load of 1kg. Thereafter, by visual inspection, the samples with scratches were evaluated as "unacceptable", and the samples without scratches were evaluated as "acceptable".

In addition to the specifications of the anti-reflective microstructure 1, Table 1 also shows evaluation test results including average reflectance and scratch resistance.

As a result, the first first having a structure such that each fine convex portion p of the antireflection fine structure 1 is substantially formed into a truncated cone or a truncated pyramid with the base diameter Db and the upper diameter Du within a certain range Examples to Ninth Examples show: i) low reflectivity at visible light wavelengths, and ii) excellent scratch resistance.

On the contrary, according to the first comparative example, the antireflection molded body 10 provided with the antireflection fine structure 1 in which the fine convex portion 1p is formed into a cone (instead of a truncated cone) is excellent in antireflection, but is very poor. May cause scratches and is therefore impractical (unacceptable).

Also, according to the antireflection molded body 10 of the second comparative example, although the fine convex portion 1p is formed in a frustoconical shape while the bottom surface 2 (base diameter Db) is so large that the pitch 4 (=400nm) is larger than the shortest of visible rays wavelength, excellent scratch resistance but poor anti-reflection ability.

Furthermore, according to the antireflection molded body 10 of the third comparative example, although the fine convex portion 1p is formed in a truncated cone while having an extremely large upper surface 3 (upper diameter Du), the scratch resistance is excellent but the antireflection capability Difference.

Although the present invention has been described with reference to specific embodiments, the present invention is not limited to the embodiments described above. Based on the above teachings, those skilled in the art can make modifications and changes to the above embodiments.

The present invention is based on prior Japanese Patent Applications No. P2006-054262 (filed in Japan on March 1, 2006) and No. P2006-293705 (filed in Japan on October 30, 2006). The entire contents of Japanese Patent Applications No. P2006-054262 and No. P2006-293705 from which priority is claimed are hereby incorporated by reference in order to prevent translation errors or omissions.

Claims (8)

1. An anti-reflection structure, comprising: a plurality of raised portions arranged at intervals shorter than the wavelength of visible rays, each of said raised portions being formed in one of a substantially frustoconical shape and a substantially frustopyramidal shape, each said raised portion Sections include: i) a bottom surface formed as one of a bottom circle and a bottom polygon inscribed in the bottom circle, a) the bottom circle and b) the bottom circle circumscribing the bottom polygon each have a value satisfying the following expression The bottom diameter Db of: 100nm<Db<380nm, ii) an upper surface formed as one of an upper circle and an upper polygon inscribed in the upper circle, each of a) the upper circle and b) the upper circle circumscribing the upper polygon has the following expression The upper diameter Du: 5nm<Du<50nm; Wherein, each of said raised portions has a head end surface curved to define a radius of curvature R satisfying the following expression: R≥[{(Du ² -Du·Db)/(4·H)} ² +(Du/2) ² ] ^1/2 wherein H represents the height of each of said raised portions. 2. The anti-reflection structure according to claim 1, wherein The bottom surfaces of the raised portions adjacent to each other are in contact with each other. 3. The anti-reflection structure according to claim 2, wherein Each said bottom surface is formed as any of the following: i) a non-oriented circle, ii) an equilateral triangle, iii) a rectangle, and iv) regular hexagon. 4. An anti-reflection molded body comprising on at least one of its first surface and second surface: Anti-reflection structure, the anti-reflection structure includes: a plurality of raised portions arranged at intervals shorter than the wavelength of visible rays, each of said raised portions being formed in one of a substantially frustoconical shape and a substantially frustopyramidal shape, each said raised portion Sections include: i) a bottom surface formed as one of a bottom circle and a bottom polygon inscribed in the bottom circle, a) the bottom circle and b) the bottom circle circumscribing the bottom polygon each have a value satisfying the following expression The bottom diameter Db of: 100nm<Db<380nm, ii) an upper surface formed as one of an upper circle and an upper polygon inscribed in the upper circle, each of a) the upper circle and b) the upper circle circumscribing the upper polygon has the following expression The upper diameter Du: 5nm<Du<50nm Wherein, each of said raised portions has a head end surface curved so as to define a radius of curvature R satisfying the following expression: R≥[{(Du ² -Du·Db)/(4·H)} ² +(Du/2) ² ] ^1/2 wherein H represents the height of each of said raised portions. 5. The antireflection molded body according to claim 4, wherein the antireflection molded body is substantially transparent. 6. A method of manufacturing an anti-reflective molded body, comprising: I) Preparation: A) A forming die with an anti-reflection structure, the anti-reflection structure comprising: a plurality of raised portions arranged at intervals shorter than the wavelength of visible rays, each of said raised portions is formed in one of a substantially frustoconical shape and a substantially truncated pyramidal shape, each of said raised portions Sections include: i) a bottom surface formed as one of a bottom circle and a bottom polygon inscribed in the bottom circle, a) the bottom circle and b) the bottom circle circumscribing the bottom polygon each have a value satisfying the following expression The bottom diameter Db of: 100nm<Db<380nm, ii) an upper surface formed as one of an upper circle and an upper polygon inscribed in the upper circle, each of a) the upper circle and b) the upper circle circumscribing the upper polygon has the following expression The upper diameter Du: 5nm<Du<50nm, Wherein, each of said raised portions has a head end surface curved to define a radius of curvature R satisfying the following expression: R≥[{(Du ² -Du·Db)/(4·H)} ² +(Du/2) ² ] ^1/2 where H represents the height of each of the raised portions, and B) a substrate for the antireflection molding; II) pressing the forming die and the substrate against each other in a state where at least one of the forming die and the substrate is heated; and III) forming the antireflection structure on at least one of the first surface and the second surface of the substrate. 7. A method of manufacturing an anti-reflective molded body, comprising: I) preparation: A) A forming die with an anti-reflection structure, the anti-reflection structure comprising: a plurality of raised portions arranged at intervals shorter than the wavelength of visible rays, each of said raised portions being formed in one of a substantially frustoconical shape and a substantially frustopyramidal shape, each said raised portion Sections include: i) a bottom surface formed as one of a bottom circle and a bottom polygon inscribed in the bottom circle, a) the bottom circle and b) the bottom circle circumscribing the bottom polygon each have a value satisfying the following expression The bottom diameter Db of: 100nm<Db<380nm, ii) an upper surface formed as one of an upper circle and an upper polygon inscribed in the upper circle, each of a) the upper circle and b) the upper circle circumscribing the upper polygon has the following expression The upper diameter Du: 5nm<Du<50nm, Wherein, each of said raised portions has a head end surface curved to define a radius of curvature R satisfying the following expression: R≥[{(Du ² -Du·Db)/(4·H)} ² +(Du/2) ² ] ^1/2 where H represents the height of each of the raised portions, and B) a substrate for the antireflection molding; II) irradiating active energy to the forming die and the substrate with an active energy ray-curable resin disposed between the forming die and the substrate; and III) forming the antireflection structure on at least one of the first surface and the second surface of the substrate. 8. An automobile part, comprising: Anti-reflection structure, the anti-reflection structure includes: a plurality of raised portions arranged at intervals shorter than the wavelength of visible rays, each of said raised portions being formed in one of a substantially frustoconical shape and a substantially frustopyramidal shape, each said raised portion Sections include: i) a bottom surface formed as one of a bottom circle and a bottom polygon inscribed in the bottom circle, a) the bottom circle and b) the bottom circle circumscribing the bottom polygon each have a value satisfying the following expression The bottom diameter Db of: 100nm<Db<380nm, ii) an upper surface formed as one of an upper circle and an upper polygon inscribed in the upper circle, each of a) the upper circle and b) the upper circle circumscribing the upper polygon has the following expression The upper diameter Du: 5nm<Du<50nm, Wherein, each of said raised portions has a head end surface curved to define a radius of curvature R satisfying the following expression: R≥[{(Du ² -Du·Db)/(4·H)} ² +(Du/2) ² ] ^1/2 wherein H represents the height of each of said raised portions.

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