JP2016528516A - Anti-reflective coating - Google Patents

Abstract

The present invention relates to optical coatings and can be used to significantly reduce the reflection of visible light from the outer surface of a display or other device for optical communication and information processing. The anti-reflective coating in various embodiments consists of two or three layers, which in various embodiments have one metal layer ranging in thickness from 2 to 12 nanometers and within a certain range. Including one or two non-metallic layers having a refractive index and thickness, the metal layer being disposed either between the non-metallic layer and the substrate or between the non-metallic layers. [Selection] Figure 1

Description

  The present invention relates to optical coatings, and more particularly to anti-reflection optical coatings that can avoid or significantly reduce the reflection of ambient light from displays and devices for optical communication and information processing.

  For example, P.I., published in 2004 by SPIE, Washington, USA. W. The well-known anti-reflective coating on substrates described in Baumeister's “Optical Coating Technology” pages 1-3, FIGS. 1-7, and pages 4-11, section 4.3.2, has a refractive index less than the substrate refractive index. And one quarter-wave optical thickness (the optical thickness of the layer is the physical thickness of the layer multiplied by the refractive index of the layer) Including. This known anti-reflective coating reduces the ambient light residual reflection from 4-5% to 1.5-2% of the bare substrate. The disadvantage of this one-layer antireflection coating is that the residual reflection is relatively high.

  For example, P.I., published in 2004 by SPIE, Washington, USA. W. Another known anti-reflective coating on a substrate, as described in Baumeister's “Optical Coating Technology” pages 4-12, Section 4.3.3.1, is a first non-metal having a refractive index greater than the substrate refractive index. And a second non-metallic layer having a refractive index less than that of the first non-metallic layer, wherein the first non-metallic layer is disposed between the second non-metallic layer and the substrate. The This known anti-reflection coating reduces the ambient light residual reflection from 4-5% of the bare substrate to 0.5-1%. The disadvantage of this two-layer anti-reflective coating lies in the bright color of the reflected light, not the required halftone.

  For example, P.I., published in 2004 by SPIE, Washington, USA. W. Further known anti-reflective coatings on substrates described in Baumeister's “Optical Coating Technology” pages 1-14, Section 1.3.1.3, alternate high and low reflectivity layers. A set of layers (4 layers or more) laminated to each other. This known anti-reflective coating reduces ambient light residual reflection from 4-5% of the bare substrate to 0.1-0.5%. The disadvantage of this multilayer anti-reflective coating lies in the relatively high production costs due to many deposited layers that are difficult to adjust.

  Reflective heat (infrared region) in the visible panel, which is highly transmissive, is disclosed in US Pat. No. 4,327,967. This panel is composed of one non-metallic layer having a refractive index of 2 or more deposited on a glass substrate, a gold layer deposited on the non-metallic layer, and a gold layer coated for neutrality of the reflected color. A thin layer of metal. The disadvantage of this panel is the relatively high reflection (> 8%) in the visible range.

  It is an object of the present invention that an anti-reflective coating on the substrate provides ambient light residual reflection of visible light as low as 0.1-0.5% at the required midtones.

  Another object of the present invention is to minimize the amount of multiple layers (3 layers or less) of the anti-reflective coating while providing low ambient light residual reflection at the required midtones, thus This ensures a low cost.

  According to the first embodiment of the invention, these objectives for visible light are one metal layer with a thickness of 2-5 nanometers, a reflectivity of 1.3-1.6 and 40-80 nanometers. An anti-reflective coating on a substrate comprising one non-metallic layer having a thickness of meters, wherein the metal layer is implemented with an anti-reflective coating disposed between the non-metallic layer and the substrate.

  According to the second embodiment of the present invention, these objects for visible light include one metal layer with a thickness of 2-12 nanometers, a refractive index of 1.7 or less and a thickness of 30-100 nanometers. An anti-reflective coating on a substrate comprising a first non-metallic layer having a thickness and a second non-metallic layer having a refractive index greater than 1.7 and a thickness of 10 to 50 nanometers, And the first non-metallic layer has a refractive index difference of 0.3 or more, the second non-metallic layer is disposed on the substrate, the metallic layer is disposed on the second non-metallic layer, Realized with an anti-reflective coating in which the metal layer is disposed on the metal layer.

  The present invention is clarified by the drawings showing some embodiments of the anti-reflective coating, without being completely covered by the full scope of the proposed technical solution and without being limited thereto.

The first of the anti-reflective coating consisting of one non-metallic layer having a refractive index of 1.6 or less and one metallic layer 2-5 nanometers thick disposed between the non-metallic layer and the substrate It is a figure which shows embodiment. FIG. 2 shows the ambient visible light reflection spectrum of the antireflection coating according to FIG. 1. An anti-reflective coating comprising a first non-metallic layer having a refractive index of 1.7 or less, a second non-metallic layer having a refractive index greater than 1.7, and a single metallic layer, wherein the second non-metallic layer comprises: FIG. 4 illustrates a second embodiment of an anti-reflective coating in which a metal layer is disposed on a substrate, a metal layer is disposed on a second non-metal layer, and a first non-metal layer is disposed on the metal layer. It is. FIG. 4 shows the ambient visible light reflection spectrum of the antireflection coating according to FIG. 3.

  1 includes one metal layer 1 having a thickness of 2 to 5 nanometers and one non-metal layer 2 having a reflectivity of 1.3 to 1.6 and a thickness of 40 to 80 nanometers. A first embodiment of an anti-reflective coating on the substrate 3 for visible light, in which the metal layer 1 is arranged between the non-metal layer 2 and the substrate 3, is shown.

  The anti-reflective coating functions as follows. Ambient white light 4 enters the antireflection coating, and includes “the interface between air and nonmetal layer 2”, “the interface between nonmetal layer 2 and metal layer 1”, and “the interface between metal layer 1 and substrate 3”. Reflected from each interface. As a result of the destructive interference of the reflected light, the total intensity of the reflected light 5 is very low in the thickness and refractive index of certain specific and appropriately selected non-metallic layers 1 and the optical properties of the metal and its thickness. Become.

  Preferably, the metal layer comprises gold Au, silver Ag, aluminum Al, copper Cu, chromium Cr, titanium Ti, nickel Ni, manganese Mn, molybdenum Mo, bismuth Bi, tin Sn, rhodium Rh, platinum Pt, antimony Sb, and Made from a metal selected from the group comprising any alloy or solid solution of these materials. In order to better adhere to the substrate 3 and the non-metal layer 2 described above, the metal layer 1 has a thickness of 1 nanometer or less, and chromium Cr, titanium Ti, nickel Ni, vanadium V, zirconium Zr, It may further include a sub-layer made from a material selected from the group comprising hafnium Hf, niobium Nb, molybdenum Mo, and any mixture, alloy, or solid solution of these materials.

  The thickness of the metal layer 1 is in the range of 2-5 nanometers depending on which metal is used and the thickness and refractive index of the non-metal layer 2. A metal thickness of less than 2 nanometers does not have a significant effect only on the visible reflection versus non-metal layer. Metal thicknesses greater than 5 nanometers increase visible reflection in the “blue” and “red” wavelength ranges, and hence total reflection of visible white light, and also produce undesirable brightly colored reflected light.

  Well-known methods such as thermal evaporation, electron beam evaporation, pulverization, ion beam, cathode pulverization, and film formation by plasma vapor chemical growth can be used to form the metal layer 1 on the substrate 3.

Non-metallic layer 2 is magnesium, calcium, barium, aluminum, lanthanum _{fluoride, MgF 2, CaF 2, AlF} 3, LaF 3, SiО 2, and any mixture of the foregoing materials, from the group comprising alloys or solid solutions, Made from selected material. Organic polymer groups consisting of acrylate polymers and fluoropolymers are also used. Other materials having a refractive index of 1.6 or less not described here can be used.

  The thickness of the non-metallic layer 2 depends on the type of non-metallic material, mainly its refractive index, and the thickness and type of the metallic layer 1, and its range is 40-80 nanometers. Well-known methods such as thermal vapor deposition, electron beam vapor deposition, pulverized vapor deposition, ion beam, cathodic pulverization, and plasma vapor chemical growth can be used for the formation of the nonmetallic layer 2. A wet coating method can also be used.

  The substrate 3 (the outer surface of the display or other device) is made from a dielectric material, for example glass or polymer.

  In FIG. 2, the ambient visible light reflection spectrum of the antireflection coating according to FIG. 1 is shown. It can clearly be seen that the residual reflection of white light is 0.35% or less and has a nearly neutral tone (due to the uniform reflection in the visible spectral region).

  In FIG. 3, a second embodiment of the present invention is shown, wherein the anti-reflective coating on the substrate 3 for visible light comprises one metal layer 1 with a thickness of 2 to 12 nanometers and 1.7 or less. A first non-metallic layer 2 having a refractive index and a thickness of 30 to 100 nanometers, and a second non-metallic layer 6 having a refractive index greater than 1.7 and a thickness of 10 to 50 nanometers. , Having a difference in refractive index between the second and first non-metallic layers of 0.3 or more, the second non-metallic layer 6 is disposed on the substrate 3, and the metallic layer 1 is the second non-metallic layer. The first non-metallic layer 2 is disposed on the metal layer 1.

  The anti-reflective coating functions as follows. Ambient white light 4 enters the antireflection coating, “the interface between air and nonmetallic layer 2”, “the interface between nonmetallic layer 2 and metal layer 1”, “metal layer 1 and second nonmetallic layer 6. And the “interface between the second non-metallic layer 6 and the substrate 3”. As a result of the destructive interference of the reflected light, the total intensity of the reflected light 5 is very low for the proper choice of metallic and non-metallic materials, their thickness and refractive index of the non-metallic layers 2 and 6.

  Preferably, the metal layer comprises gold Au, silver Ag, aluminum Al, copper Cu, chromium Cr, titanium Ti, nickel Ni, manganese Mn, molybdenum Mo, bismuth Bi, tin Sn, rhodium Rh, platinum Pt, antimony Sb, and Made from a metal selected from the group comprising any mixture, alloy, solid solution, or intermetallic compound of the foregoing materials. In order to adhere the non-metallic layer 6 and the non-metallic layer 2 to the good port, the metal layer 1 has a thickness of 1 nanometer or less, and chromium Cr, titanium Ti, nickel Ni, vanadium V, It can further include a sub-layer made from a material selected from the group comprising zirconium Zr, hafnium Hf, niobium Nb, molybdenum Mo, and any mixture, alloy, solid solution, or intermetallic compound of the foregoing substances.

  The thickness of the metal layer 1 is 2-12 nanometers, depending on the type of metal and the thickness and refractive index of the non-metal layers 2 and 6. Metal thicknesses less than 2 nanometers do not significantly affect visible reflections and non-metallic layers. Metal thicknesses greater than 12 nanometers increase visible reflection in the “blue” and “red” wavelength ranges, and thereby total reflection of visible white light, and also produce a bright color of undesirable reflected light.

  Known methods for forming the metal layer 1 on the non-metal layer 6 include magnetron sputtering, thermal evaporation, electron beam, pulverization, ion beam, cathode pulverization, (plasma growth) vapor deposition by chemical vapor deposition, and the like. It has been.

  Known methods for forming the nonmetallic layers 2 and 6 include magnetron sputtering, thermal evaporation, electron beam evaporation, sol-gel, (plasma growth) chemical vapor deposition, and the like.

The non-metallic layer 2 having a refractive index of 1.7 or less includes magnesium, calcium, barium, aluminum, lanthanum fluoride, MgF ₂ , CaF ₂ , BaF ₂ , AlF ₃ , LaF ₃ , silicon dioxide SiO ₂ , and the aforementioned Made from a material selected from the group comprising any mixture, alloy or solid solution of substances, and organic polymer groups consisting of acrylate polymers and fluoropolymers. Organic polymer groups consisting of acrylate polymers and fluoropolymers are also used. Other materials having a refractive index of 1.7 or less not described here can also be used.

The thickness of the nonmetallic layer 2 depends on the type of the nonmetallic material, mainly its refractive index and thickness, and the type of the metallic layer 1, and is 30 to 100 nanometers. The second non-metallic layer 6 having a refractive index greater than 1.7 includes sapphire Al ₂ O ₃ , titanium dioxide TiO ₂ , zinc sulfide ZnS, tantalum pentoxide Та ₂ O ₅ , zinc selenide ZnSe, gallium phosphide GaP, Gallium nitride GaN, indium tin oxide ITO, niobium pentoxide Nb ₂ O ₅ , lead molybdate PbMoO ₄ , boron nitride BN, silicon nitride Si ₃ N ₄ , aluminum nitride AlN, silicon Si, germanium Ge, selenium Se, semiconductor A Made from a material selected from the group comprising ₃ B ₅ type, semiconductor A ₂ B ₆ type, semiconductor A ₅ B ₆ type (arsenic, antimony, and bismuth chalcogenide), and any mixture or solid solution of the aforementioned substances .

  The thickness of the non-metallic layer 6 depends on the type of non-metallic material of both the layers 2 and 6, mainly its reflectivity, and the thickness and type of the metallic layer 1 and is 10-50 nanometers.

  The difference between the refractive indices of the second and first non-metallic layers is 0.3 or greater. Differences less than 0.3 increase the visible reflection in the “blue” and “red” wavelength regions, and the total reflection of visible white light, and also produce undesirable brightly colored reflected light.

  The substrate (the outer surface of the display or other device) is made from a dielectric material such as glass or polymer.

  In FIG. 4, the ambient light reflection spectrum of the antireflection coating according to FIG. 3 is shown. It can clearly be seen that the residual reflection of white light is less than 0.2% and has an intermediate tone (due to uniform reflection in the visible spectral region).

  The technical results ensured by the aggregated attributes of the anti-reflective coating described herein can be reduced to 0.1-0.5% in intermediate tones where ambient light residual reflection is required. Similarly, the anti-reflective coating has three layers or less to ensure low cost.

  This result is achieved by an optimal balance of non-metallic layer thicknesses, their refractive index, and metallic layer thickness.

Claims (9)

An anti-reflective coating on a substrate for visible light,
One metal layer of 2-5 nanometers,
One non-metallic layer having a reflectivity of 1.3 to 1.6 and a thickness of 40 to 80 nanometers,
An anti-reflective coating, wherein the metal layer is disposed between the non-metal and the substrate.   The metal layer may be gold Au, silver Ag, aluminum Al, chromium Cr, titanium Ti, nickel Ni, manganese Mn, molybdenum Mo, bismuth Bi, tin Sn, and any mixture, alloy, solid solution, or metal of the aforementioned substances. The antireflective coating of claim 1 made from a material selected from the group comprising an intercalation compound.   The metal layer has a total thickness of 1 nanometer or less, and chromium Cr, titanium Ti, nickel Ni, vanadium V, zirconium Zr, hafnium Hf, niobium Nb, molybdenum Mo, and any mixture, alloy of the foregoing substances The antireflective coating of claim 2 further comprising a sublayer made from a metal selected from the group comprising: or a solid solution. Said non-metallic layer comprises MgF ₂ , CaF ₂ , BaF ₂ , SiO ₂ , AlF ₂ , LaF ₃ , and any mixture or solid solution of the aforementioned substances, and organic polymer groups including acrylate polymers and fluoropolymers. The antireflective coating of claim 1 made from a material selected from the group. An anti-reflective coating on a substrate for visible light,
One metal layer with a thickness of 2-12 nanometers;
A first non-metallic layer having a refractive index of 1.7 or less and a thickness of 30 to 100 nanometers;
A second non-metallic layer having a refractive index greater than 1.7 and a thickness of 10 to 50 nanometers,
Having a difference between the refractive indices of the second and first non-metallic layers of 0.3 or more;
An antireflective coating, wherein a second non-metallic layer is disposed on the substrate, the metallic layer is disposed on the second non-metallic layer, and the first non-metallic layer is disposed on the metallic layer.   The metal layer may be gold Au, silver Ag, aluminum Al, chromium Cr, titanium Ti, nickel Ni, manganese Mn, molybdenum Mo, bismuth Bi, tin Sn, and any mixture, alloy, solid solution, or metal of the aforementioned substances. 6. The anti-reflective coating of claim 5 made from a material selected from the group comprising intermetallic compounds.   The metal layer has a total thickness of 1 nanometer or less, and chromium Cr, titanium Ti, nickel Ni, vanadium V, zirconium Zr, hafnium Hf, niobium Nb, molybdenum Mo, and any mixture, alloy of the foregoing substances The antireflective coating of claim 6 further comprising a sublayer made of a metal selected from the group comprising: or a solid solution. The first non-metallic layer comprises MgF ₂ , CaF ₂ , BaF ₂ , SiO ₂ , AlF ₃ , LaF ₃ , and any mixture or solid solution of the aforementioned substances, and an organic polymer group consisting of an acrylate polymer and a fluoropolymer. 6. The antireflective coating of claim 5 made from a material selected from the group comprising. Said second non-metal layer of the foregoing, the titanium dioxide TiO _2, zinc sulfide ZnS, tantalum pentoxide Та ₂ О _5, zinc selenide ZnSe, gallium phosphide GaP, indium tin oxide ITO, gallium nitride GaN, niobium pentoxide Nb ₂ O ₅ , lead molybdate PbMoO ₄ , boron nitride BN, silicon nitride Si ₃ N ₄ , aluminum nitride AlN, silicon Si, germanium Ge, selenium Se, semiconductor A ₃ B ₅ type, semiconductor A ₂ B ₆ type, semiconductor a ₅ B ₆ type (arsenic, antimony, and bismuth chalcogenide), and is fabricated from a material selected from the group consisting of any mixture or solid solution of the foregoing material, anti-reflective coating according to claim 5.

Images