KR20090023178A - Antireflective structure and antireflective molded body, and vehicle component using the antireflective molded body - Google Patents

Abstract

An antireflective structure, an antireflective molded body, and a vehicle component using the antireflective molded body are provided to perform an antireflective function and a damage preventing function by forming two reflective surfaces and a minute convex unit with a truncated cone or pyramid shape. An antireflective structure(1) includes a planar surface and a minute structure layer. The minute structure layer includes a circular or polygonal bottom surface. A plurality of minute convex parts(2) are arranged on the plane surface in a pitch. The minute convex part has a truncated cone or pyramid shape with circular diameter circumscribed in the bottom shape. The diameter of the bottom circumscribed circle and the pitch are smaller than the wavelength of the electromagnetic wave. The antireflective structure has minute convex parts with the truncated cone or pyramid shape including a flat tip.

Description

ANTIREFLECTIVE STRUCTURE AND ANTIREFLECTIVE MOLDED BODY, AND VEHICLE COMPONENT USING THE ANTIREFLECTIVE MOLDED BODY}

The present invention provides an antireflection structure having excellent anti-reflection function as well as anti-reflection of electromagnetic waves, and having such a structure, and as an anti-reflective panel, for example, a body such as a vehicle, a ship, an aircraft, a variety of instruments, and a display device. The molded object which can be used suitably etc. is related.

In the fields of aircraft, automobiles, ships, etc., it is necessary to prevent reflection of electromagnetic waves at various places, such as stealth technology not reflected by radar, IR measurement cameras such as inter-vehicle measurement, instrument covers, and liquid crystal display devices.

For example, an instrument front cover is fitted into a driver's seat of a vehicle on a front surface of a display unit in which various instruments such as a speed gauge and a fuel gauge are collectively stored. However, this may make it difficult to see various displays on the front window or side window, so the instrument hood should be placed above to block the incidence of external light on the instrument display. have.

As a structure for preventing the reflection of light, a multilayer antireflection film composed of a plurality of thin films having different refractive indices is known, but it is possible to further lower the reflectance than such a multilayer antireflection film. (For example, refer patent document 1).

[Patent Document 1] Japanese Patent Application Laid-Open No. 2002-267815

Patent Document 1 discloses an antireflection structure in which the refractive index of light is changed in the thickness direction by forming a myriad of fine irregularities made of a transparent material at a pitch below the wavelength of light on the surface of the transparent molded article.

That is, for example, the myriad of fine concavo-convexes forming a wave or a triangle are formed on the surface, so that the presence ratio of the transparent material is almost close to 0% at the outermost surface of the concave-convex, and substantially equal to the refractive index of air. On the other hand, at the bottom of the unevenness, the presence ratio of air is almost close to 0%, which is equivalent to the refractive index of the transparent material, and at the middle part, the refractive index according to the cross-sectional area occupied by the transparent material in the cross section. Thereby, the refractive index of light will change continuously from the refractive index of air to the refractive index of a transparent material in the thickness direction of the said antireflection structure. As a result, the antireflection performance superior to the said antireflection film can be exhibited by the principle similar to the multilayer antireflection film which consists of several thin films with different refractive index (in this case, the refractive index changes in steps).

However, in the structure described in Patent Document 1, the reflectance of light can be reduced, but the tip of the fine unevenness is easily broken, and the structure is damaged by contacting the surface of the structure or by wiping the surface, so that the antireflection performance is improved. There was a problem of being damaged.

This invention is made | formed in order to solve the said subject in the conventional antireflection structure which consists of a fine uneven structure formed by the pitch and size below the wavelength of an incident electromagnetic wave. The object of the present invention is to provide an antireflection structure that optimizes the tip shape of the convex portion in the fine concavo-convex structure, thereby improving the antireflection function of the electromagnetic waves and preventing the break of the tip of the fine convex portion. It is in doing it. That is, the present invention provides an antireflection structure having both an antireflection function and damage resistance.

The present invention finds that the above object can be achieved by smoothing the tip portion of each convex portion constituting the fine concavo-convex structure, making the fine convex portion in the shape of a truncated cone or the pyramid, and forming two reflective surfaces. The present invention has been accomplished.

The present invention is based on the above findings, and the antireflection structure of the present invention has a substantially circular or polygonal shape, and a myriad of fine convex portions forming a truncated cone shape or a truncated cone shape having a bottom surface smaller than the wavelength of the incident electromagnetic wave. It is arranged in the pitch shorter than the wavelength of the electromagnetic wave which injects, and it has a reflecting surface between the tip part of these horn-shaped fine convex parts, and these horn-shaped fine convex parts, respectively.

According to the present invention, a polygon in which the shape of the individual fine convex portions constituting the antireflection structure is in the shape of a truncated cone or the pyramid, and the bottom surface is inscribed in the circle of the diameter D or the circle of the diameter D. (However, D <λ: wavelength of incident electromagnetic wave) arranged at a pitch P (where P <X), and the flat portion between the tip end of the horn-shaped fine convex portion and the convex portion at the proximal end of these fine convex portions. Since the reflection surfaces are formed respectively, the height of the fine convex portions can be lowered without increasing the reflectance, and both the antireflection function and the damage resistance can be achieved.

Hereinafter, the antireflective structure of the present invention and the antireflective molded article to which the microstructure is applied will be described in more detail together with the production method, the embodiment, and the like.

The antireflective structure of the present invention comprises a myriad of fine convex portions forming a truncated truncated or pyramidal shape as described above. The antireflective structure includes a front end portion and a reflecting surface between these horn shaped fine convex portions, respectively, and at the bottom of the fine convex portion. The size is smaller than the wavelength of the incident electromagnetic wave and is arranged at a pitch shorter than this wavelength.

Fig. 1 shows an example of an embodiment of the antireflective structure of the present invention, and the antireflective structure 1 of the present invention includes a myriad of fine convex portions 2 having a flat truncated cone or a truncated pyramid shape (in this example, a truncated cone). ) Has a structure arranged at a pitch P shorter than the wavelength [lambda] of the incident electromagnetic wave. At this time, the bottom face size of the fine convex portion, that is, the bottom diameter in the case of a truncated cone and the diameter of the circle circumscribed to the bottom polygon in the case of a truncated cone is smaller than the wavelength? Of the incident electromagnetic wave.

Therefore, the refractive index of the electromagnetic wave in each cross section determined by the existence ratio of the structural material and the air in each step surface in the thickness direction of the antireflection structure is continuous from the refractive index of the air to the refractive index of the material toward the thickness direction. By being changed to, the antireflection property of electromagnetic waves is exhibited. On the other hand, since the tip portion of each fine convex portion 2 is flattened, the electromagnetic waves reflected from the flat portions between the fine convex portions 2 are canceled out from the electromagnetic waves reflected at the tip portion, thereby enabling further low reflection.

Moreover, since the tip is smooth, it is hard to be damaged even if it is rubbed with another member or rubbed, and the antireflection function of electromagnetic waves can be made compatible with damage resistance with a minimum effect on the antireflection performance.

As for the size of the horn-shaped fine convex portion 2, as shown in Fig. 2A, when the shape is a truncated cone, when the diameter of the bottom surface is D, D < It is necessary to set it to D <380 nm in order to prevent reflection of visible light especially. Moreover, it is preferable to set it to D <= 250nm from the viewpoint of preventing coloring of the reflected light by diffraction. In addition, it is preferable that D≤150 nm for ultraviolet rays and D≤780 nm for near infrared rays. That is, when the bottom dimension D becomes equal to or more than the wavelength? Of the incident electromagnetic wave, the pitch P between the adjacent fine convex portions 2 cannot be made shorter than the wavelength?, And the electromagnetic wave is diffracted, It does not become antireflection.

In addition, when the shape of the fine convex part 2 is a pyramidal shape as shown to FIG.2 (b)-FIG.2 (d) (in the figure, as a typical example, a square horn, a hexagonal horn, and a tripod) The horns are respectively shown), and have a diameter D of a circle circumscribed to the polygon forming the bottom face, and the bottom face size.

In the present invention, in order to cancel the reflected electromagnetic wave generated from the tip of the fine convex portion 2 and the flat portion between these fine convex portions, the occupancy ratio (Rt and Rb) between the tip reflective surface and the fine convex portion And the height H of the fine convex portions become important.

The reflecting surface occupancy rate Rb between the tip reflecting surface occupancy rate Rt and the fine convex portion is the occupancy ratio of the reflecting surface between the tip reflecting surface and the fine convex portion when the repeated one unit of the antireflection structure 1 is extracted. .

Specifically, as shown in Fig. 3, when the antireflection structure 1 is viewed from above, first, the portion forming the plane in the distal end portion of the fine convex portion 2 is the tip reflecting surface 2t and the fine convex portion. It is formed in the base end side of the part 2, and the planar part between adjacent fine convex parts is made into the reflecting surface 2b between fine convex parts. Then, the area ratio of the tip reflecting surface 2t with respect to the unit area (the area of 1 unit forming a hexagon in the drawing) is determined by the tip reflecting surface occupancy rate Rt, similarly between the fine convex portions with respect to the hexagonal unit area ( The area ratio of 2b) is defined as the reflection surface occupancy ratio Rb between the fine convex portions.

In the antireflection structure 1 of the present invention, the antireflection property of electromagnetic waves is improved when the ratio of the reflecting surface occupancy ratio between the tip portion and the fine convex portion and Rt / Rb is 0.2 to 2.0. Moreover, it is preferable that this Rt / Rb ratio is 0.5-1.6.

Further, the shape of the tip end portion of the fine convex portion 2 is not particularly limited as long as it is in a range that satisfies the above-described occupancy ratio, and may not necessarily be a perfect plane. That is, depression, expansion, irregularities, etc. within 20 nm in height do not significantly affect the reflectance.

Next, the height H of the fine convex portion 2 has the greatest effect when the phase of the reflected electromagnetic wave from the tip end portion of the reflected electromagnetic wave and the fine convex portion is offset by p / 2 in order to cancel the incident electromagnetic wave. Specifically, the height (H) = [incident wavelength (λ) / (2 x average refractive index (n))] x is represented by the formula (1), and the value of A is preferably in the range of 0.6 to 1.4, More preferably A = 0.8 to 1.2. In addition, the average refractive index here means the refractive index with respect to the wavelength of an incident electromagnetic wave.

When the value of A is smaller than 0.6, the height H of the fine convex part 2 becomes low, and the reflected electromagnetic waves from two reflection surfaces cannot become low reflection in the target wavelength range. In addition, when the value of A exceeds 1.4, since the height H of the fine convex portion 2 increases and the refractive index changes smoothly, some degree of antireflection can be ensured, but damage resistance deteriorates. There is a tendency.

In particular, in order to prevent reflection in visible light, it may be designed so that the vicinity of 540 to 560 nm having high sensitivity to the human eye becomes the minimum reflectance.

The range of the height H of the fine convex portion 2 depending on the type of electromagnetic wave may be a range derived from the above formula, but is particularly preferably 80 to 160 nm in the ultraviolet region and 160 to 350 nm in the visible region. More preferably, it is 160-240 nm, 350 nm-about 45 micrometers in an infrared region.

In addition, the average refractive index at this time is the numerical value which averaged the refractive index from the front-end | tip of the fine convex part 2 to a base end (bottom). The method of deriving the average refractive index divides the fine convex part 2 of a unit unit 100 in the direction perpendicular | vertical to a height direction, derives a refractive index from the ratio of the solid and space in each unit, and calculates an average value.

The fine convex part 2 which comprises the anti-reflective structure of this invention forms a "pyramidal shape" as mentioned above, and it showed that it is a truncated cone in FIG. However, as the shape of the fine convex part 2 in this invention, not only an accurate truncated cone (straight line of a bus bar) and a truncated pyramid (straight line of a corner, a flat side surface) but also a shape which the cross section becomes small gradually from the bottom face to the front end side The shape may be a truncated truncated cone, or a truncated truncated pyramid having a curved side.

In addition, the straight line which connects the center of the bottom face of the fine convex part 2, and the center point of the top face is not necessarily perpendicular to a bottom face, but may be inclined.

As described above, in the present invention, the "horn shape" means not only an accurate truncated cone or a pyramid but also a flat or inclined tip of a modified pyramid having a flank or acorn-shaped deformation cone or a curved surface. It means the shape included.

The line connecting the upper and lower floors in the trapezoidal cross section perpendicular to the bottom surface passing through the center of the ridge shape of the fine convex portion 2 and the front end surface of the fine convex portion 2 is represented by the following formula (2). It is preferable that it is in the shape represented by the linear formula (1 <= m <= 1.5) as shown by (). Thereby, the ratio of the change of the refractive index from the top of the fine convex part to the bottom in the antireflection structure becomes uniform, and the antireflection function can be further improved.

In other words, the height of the bottom in the vertical cross section passing through the center of the fine convex portion 2 on the X axis to the peak point appearing as an intersection point when the ridge line is extended is h, and the peak point is on the Z axis axis. When taken into consideration, the X coordinate value on the ridgeline can be expressed as shown in Fig. 4 based on the following equation (2). At this time, the integer term may be added and corrected by the position of the stationary point.

X = (D / 2) x {1-(Z / h) ^m }. (2)

In addition, about the bottom shape of the micro-convex part 2, about the circle | round | yen shape, ie, round, oval, egg-shaped, polygonal triangle, square, pentagon, hexagon, and the shape of the shape where each side of a polygon expands outward, the middle of a circle and a polygon One having the same shape as the above can be employed. Among these, a circle, a rectangle, and a hexagon are preferable because they are relatively easy to manufacture and can be arranged closely.

In addition, about such a fine convex part 2, the diameter D of the circle which circumscribes to the shape which forms a bottom face is made into bottom face size. That is, in the case of a circular bottom face, the diameter, the long axis diameter in the case of an ellipse or an egg shape, and the diameter of the circle which circumscribes this in a polygon correspond to D.

As for the arrangement of the fine convex portions 2, in view of forming the reflective surface 2b between the fine convex portions on the proximal end side of the fine convex portions 2 (see FIG. 3), the fine arrangement when the bottom face is circular can do.

On the other hand, when the bottom shape of the fine convex part 2 is an equilateral triangle, square, a regular hexagon, etc. which can be spread | discovered without a clearance on a plane, it is necessary to arrange | position the space | interval between the fine convex parts 2 comrades.

As the material of the horn-shaped fine convex portion 2, the same basic materials as those described later can be used. However, in view of further improving durability in addition to the antireflection property, the resin and the sphere equivalent diameter as described later are described. Therefore, it is preferable to consist of particles of 10-50 nm.

Such particles are not particularly limited, and for example, inorganic particles such as organic particles such as polymethyl methacrylate, polystyrene, amide, imide, polyester, silicon dioxide, titanium dioxide, zirconium dioxide and aluminum oxide, Metal colloidal particles such as gold, silver, platinum, iron, and ceramic particles such as barium titanate may be used. In particular, inorganic oxides having a high compressive strength and good adhesion to the resin due to surface modification, etc., are preferred for improving durability. Do. There is no restriction | limiting in particular also about the shape of these particle | grains, A spherical shape, a rugby ball shape, a star candy shape, an amorphous form, a porous shape, etc. are mentioned.

In addition, as the size of the particles, if the particles are too small, the exposure of the particles to the surface is reduced, and the wear of the resin is increased. If the particles are too large, the particles are less likely to enter the fine convex portion 2 during molding. Since durability may not be improved, it is preferable that it is 10-50 nm in terms of a sphere diameter. More preferably, it is the range of 10-20 nm.

As the particle strength, one having a compressive strength of 500 MPa or more is preferable, and when it is lower than this, there is a possibility that the particle part is not likely to wear out, and durability may not be secured.

The amount of the particles added is preferably in the range of 20 to 60% by weight because the durability of the fine protrusions is not improved. If the amount of the particles is too high, the dispersion state of the particles may deteriorate and the molded article may be deteriorated or the transparency may deteriorate.

In the case of the base material and the visible light, the antireflection structure of the present invention can be formed on one side of the transparent base material, preferably on both sides, to form an antireflection molded body. Application to transparent panels, such as show windows and display cases, can reduce reflection of external light and indoor lighting, effectively prevent projection of reflected images, and improve visual confirmation of images, displays, and internal displays.

In addition, the same antireflection effect can be obtained by applying to various parts including automobiles, for example, glass for windows and roofs, instrument front covers, headlamps, rear finishers, and films used for the frontmost surfaces of display devices such as liquid crystals.

In manufacturing the said anti-reflective molded object of this invention, the shaping | molding die provided with the fine concave part which inverted the above-mentioned countless fine convex parts 2 was prepared, and the one or both of this molding die and a base material were heated. By relatively pressing both in the state, the above antireflection structure 1 can be formed on the surface of the substrate.

Furthermore, by irradiating an active energy ray in the state which an active energy ray curable resin interposed between the said molding metal mold | die and a base material, and hardening the said resin, the surface of the said base material as above-mentioned antireflection structure ( 1) may be molded to form an antireflection molded body.

As a material of the said base material, what has transparency typically is preferable, For example, polyethylene, polypropylene, polyvinyl alcohol, polyvinylidene 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 crystalline polymer, fluororesin, polyarylate, Thermoplastic resins such as polysulfone, polyethersulfone, polyamideimide, polyetherimide, and thermoplastic polyimide, phenol resin, melamine resin, urea resin, epoxy resin, unsaturated polyester resin, alkyd resin, silicone resin, and diaryl phthalate Resin, Polyamide Bismaleimide, Polybisamide Tree Thermosetting resins, such as an azole, and the material which mixed these 2 or more types can be used.

Moreover, as active energy ray hardening resin which starts superposition | polymerization and hardens | cures by irradiation of ultraviolet rays etc., for example, ultraviolet curable acrylic urethane resin, ultraviolet curable polyester acrylate resin, ultraviolet curable epoxy acrylate resin, UV-curable polyol acrylate resins, UV-curable epoxy resins, and the like, and the like, may be used a polymerization initiator that generates radicals by irradiating active energy rays, or a curing agent such as isocyanate may be added to solidify more firmly. .

In addition, as an active energy ray used here, although an ultraviolet-ray, an X-ray, other electron beams, an electromagnetic wave, etc. are mentioned typically, it is not specifically limited.

In addition, it is also possible to use inorganic transparent materials such as glass, in which case, by cutting the glass surface with an electron beam or the like, a method of forming the antireflection structure as described above, or the type provided with the antireflection structure of the present invention The antireflection structure can be formed on the surface of the substrate by a method of flowing the inorganic transparent material melted into the substrate).

EXAMPLE

In the following, the present invention will be described in more detail based on Examples. It goes without saying that the present invention is not limited only to these examples.

(First embodiment)

After using the metal mold | die produced by the commercially available electron beam drawing apparatus, this metal mold | die was heated at 170 degreeC, and it pressed to both surfaces of a polycarbonate base material at the pressure of 10 Mpa for 1 hour, and then cooled to 70 degrees C or less. As a result, as shown in Table 1, the fine convex portions 2 having a truncated conical shape having a diameter D of the bottom surface of 1000 nm, a diameter of the front end surface of 250 nm, and a height H of 750 nm are hexagonal finely divided. An anti-reflective molded article having both sides with an antireflective structure 1 arranged at (pitch: 1000 nm) was produced.

And the obtained molded object was irradiated with the infrared ray of wavelength 2000nm, the reflectance in 0 degree of incidence angle and 0 degree of measurement angle was measured, and antireflection performance was evaluated.

In addition, when the surface of the said molded object was reciprocated and rubbed 5000 times with surface pressure 392 kPa, the generation | occurrence | production state of the damage after visual observation can be observed and it can confirm that the occurrence of damage is "x", and it was not recognized Damage resistance was evaluated as "(circle)". These results are shown in Table 2.

(2nd Example)

By using the same mold manufactured by the same electron beam drawing apparatus and repeating the same operation as in the first embodiment, the diameter D of the bottom surface is 300 nm on both surfaces of the polymethyl methacrylate substrate, as shown in Table 1. The reflection provided with the anti-reflection structure 1 in which the fine convex part 2 which comprises the truncated conical part 2 of 45 nm in diameter and 220 nm in height H is arranged in a hexagonal fine state (pitch: 300 nm). The prevention molded object was produced.

And the obtained molded object was irradiated with the visible light of wavelength 555nm, the incidence angle 0 degree, the reflectance in the measurement angle 0 were measured, antireflection performance was evaluated, and damage resistance was evaluated by the above-mentioned method. This result is combined with Table 2 and shown.

(3rd to 5th, 8th, and 9th embodiments)

By repeating the same operation as in the second embodiment, the anti-reflection in which the fine convex portions 2 which form a truncated conical shape each having the dimensions shown in Table 1 on both sides of the polymethyl methacrylate substrate are arranged in a hexagonal fine state The anti-reflective molded object provided with the structure (1) was produced, respectively.

And the reflectance and damage resistance were each evaluated about the obtained molded object by the same method as Example 2, respectively. These results are combined with Table 2 and shown.

(Sixth and seventh embodiments)

By repeating the same operation as in the second embodiment, the dimensions shown in Table 1 are respectively prepared on both sides of the polymethyl methacrylate base material, and the ridges extending from the circumferential end portion to the bottom circumference portion are order (m) = 1.2. And the antireflection molded body provided with the antireflection structure 1 in which the truncated conical fine convex portions 2 represented by the linear formula (1) of 1.5 were arranged in a hexagonal fine state, respectively.

And the reflectance and damage resistance were each evaluated about the obtained molded object by the same method as Example 2, respectively. These results are combined with Table 2 and shown.

(Example 10)

Toluene-dispersed silica sol (formulated particle diameter: 20 nm, compressive strength of particles: 6.2 kPa) in 70 mass% of UV-cured acrylic resin (polymethyl methacrylate) and 10 mass% of γ methacryloxypropyl trimethoxysilane. , Concentration: 20% solution) was mixed so that the solid content was 20% by weight, and was applied on a polymethyl methacrylate substrate so as to have a film thickness of 50 µm.

Next, the surface was pressed with the same mold as used in the first embodiment, and then irradiated with ultraviolet light for 10 minutes using a high-pressure mercury lamp (80 W) to form a resin and silica particles, as shown in Table 1 below. The anti-reflective molded object provided with the anti-reflective structure 1 by which the truncated conical fine convex part 2 of the dimension was arranged in the hexagonal fine state was produced.

And the reflectance and damage resistance of the obtained molded object were evaluated by the method similar to Example 1. These results are combined with Table 2 and shown.

(Example 11)

The same anti-reflective molded article was repeated by repeating the same operation as in the tenth example, except that the toluene-dispersed silica sol was replaced with a converted particle diameter of 10 nm and the concentration was 30%, and the same mold as that used in the third example was used. Made.

And the reflectance and damage resistance of each obtained molded object were evaluated by the method similar to Example 2. These results are combined with Table 2 and shown.

(First Comparative Example)

Using the metal mold | die produced by the same electron beam drawing apparatus, operation similar to the said 2nd Example is repeated, and as shown in Table 1, the diameter D of the bottom face is 200 nm on both surfaces of a polymethylmethacrylate base material. The anti-reflective molded object provided with the anti-reflective structure by which the convex part which forms conical shape whose height H is 200 nm was arranged in hexagonal fine state (pitch: 200 nm) was produced.

And the reflectance and damage resistance were each evaluated about the obtained molded object by the same method as Example 2, respectively. These results are combined with Table 2 and shown.

Table 1

[Table 2]

As a result, in the first to eleventh embodiments, which are the scope of the present invention, it was confirmed that the reflectance with respect to the incident electromagnetic wave was low.

On the other hand, in the antireflective molded article of the first comparative example, since the fine convex portions form a conical shape and do not have a reflecting surface of the incident electromagnetic wave at the distal end, the antireflection function is inferior and damage resistance is also inferior.

In addition, about the damage resistance of the said 10th and 11th Example, although the difference with another Example was not able to be confirmed by the said evaluation method, when it evaluated by the test of stricter conditions, 1st-9th implementation is carried out. It is predicted to show superior damage resistance than the example.

1 is a perspective view showing an antireflection structure of the present invention;

Fig. 2A is an explanatory diagram showing a case of a truncated cone as an example of the shape of the fine convex portions forming the antireflection structure. Fig. 2B is an explanatory diagram showing a case of a square pyramid shape as an example of the shape of the fine convex portions constituting the antireflection structure. Fig. 2C is an explanatory diagram showing a case of a hexagonal cone shape as an example of the shape of the fine convex portions constituting the antireflection structure. Fig. 2 (d) is an explanatory view showing a triangular pyramid shape as an example of the shape of the fine convex portions constituting the antireflection structure.

Fig. 3 is a plan view of the antireflection structure for explaining the front surface reflecting surface occupancy and the reflecting surface occupancy between the fine convex portions in the present invention. A graph showing the relationship between the upper surface dimension (d) of the fine convex portion and the average reflectance.

Fig. 4 is an explanatory diagram showing the ridge shape of the fine convex portions in the m-th order linear form in the antireflection structure of the present invention.

 <Explanation of symbols for the main parts of the drawings>

1: antireflection structure

2: fine convexity

Rt: Tip Reflector Share

Rb: Reflective surface occupancy between the fine convex portions

Claims (11)

Flat floor, It is composed of a microstructure layer having a circular or polygonal bottom surface, a myriad of fine convex portions having a diameter of a circle circumscribed to the bottom shape or forming a truncated pyramid shape with a pitch P on the planar layer, It has a reflecting surface on the surface of the planar layer between the tip end portion of the horn-shaped fine convex portion and the horn-shaped fine convex portion, and the circumscribed circle diameter (D) and pitch (P) of the bottom face are smaller than the wavelength (λ) of the electromagnetic wave incident. An antireflection structure, characterized in that. It is an antireflection structure which has a circular or polygonal bottom surface, and countless fine convex parts which form a truncated cone shape or a truncated pyramid shape with the diameter of the circle which circumscribes the said bottom face shape are arranged on the surface at pitch P, The wavelength of the electromagnetic wave which has a reflecting surface between the tip end of the said horn-shaped fine convex part, and the horn-shaped fine convex part in the base end side of the said fine convex part, and the circumscribed circle diameter D and pitch P of the said bottom face inject. An antireflection structure, which is smaller than (λ). 3. The microstructure of claim 1, wherein the ratio Rt / Rb of the tip reflecting surface occupancy rate Rt between the horn-shaped fine convex portion and the reflecting surface occupancy rate Rb between the fine convex portions is 0.2 to 2; The height H of the convex portion is a value calculated by the following equation (1). H = A (λ / 2n)... (One) (Wherein n is the average refractive index of the micro-convex portion, and A represents any value in the range of 0.6 to 1.4) The antireflection structure according to claim 3, wherein the ratio (Rt / Rb) is 0.5 to 1.6. The antireflection structure according to claim 1 or 2, wherein the ridge shape of the horn-shaped fine convex portion is a curve represented by the following formula (2), and the order m is 1 or more and 1.5 or less. X = (D / 2) x {1-(Z / h) ^m }. (2) (Wherein h represents the height to the peak point represented as the intersection of the extension lines of the ridges of the horn-shaped fine protrusions) The circumscribed circle diameter (D) and the pitch (P) of the bottom surface of the horn-shaped fine convex portion are 380 nm or less, and the height (H) of the fine convex portion is 160 to 350 nm. rescue. 7. The antireflection structure according to claim 6, wherein a circumscribed circle diameter (D) and a pitch (P) of the bottom face of the horn-shaped fine convex portion are 250 nm or less. The antireflection structure according to claim 1 or 2, wherein the horn-shaped fine convex portion is made of particles and resin having a converted diameter of 10 to 50 nm. The anti-reflective molded object of Claim 1 or 2 is provided in at least one surface of the base material. The antireflective molded article according to claim 9, wherein the substrate is transparent. An antireflective molded article according to claim 9 was used.

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