DE102016100346A1 - RESISTANT HYBRID PIGMENTS OF AN OMNIDIRECTIONAL STRUCTURAL COLOR FOR EXTERNAL APPLICATIONS - Google Patents

Abstract

Hybrid pigment of an omnidirectional structural color. The pigment has a color visible to the human eye and has very little or no discernible color shift when exposed to broadband electromagnetic radiation (e.g., white light) and from angles between 0 and 45 ° relative to the normal of an outer Surface of the pigment is considered. The pigment is in the form of a multilayer stack with a reflective core layer and at least two high refractive index (nh) layers. One of the nh layers may be a dry deposited nth dielectric layer extending over the reflective core layer, and one of the layers may be a wet deposited nth n protective layer. An absorber layer extending between the dry-deposited nh dielectric layer and the wet-deposited nh external protective layer may also be included.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation-in-part (CIP) of U.S. Patent Application Serial No. 14 / 471,834, filed August 28, 2014, which in turn is a CIP of U.S. Patent Application Serial No. 14 filed August 15, 2014 460,511, which in turn is a CIP of U.S. Patent Application Serial No. 14 / 242,429 filed April 1, 2014, which in turn is a CIP of U.S. Patent Application Serial No. 14 / 138,499 filed December 23, 2013, which in turn a CIP of U.S. Patent Application Serial No. 13 / 913,402, filed June 8, 2013, which in turn is a CIP of U.S. Patent Application Serial No. 13 / 760,699 filed February 6, 2013, which is a CIP of the prior art filed on Feb. 10, 2013. No. 13 / 572,071 filed August 5, 2011, which is in turn a CIP of US Patent Application Serial No. 13 / 021,730 filed February 5, 2011, which in turn is a CIP of 12 / 793,772 (filed Jun. 4, 2010). U.S. Patent 8,736,959 ), which in turn issued a CIP of 12 / 388,395 ( U.S. Patent 8,749,881 ), which in turn issued a CIP of US Patent Application Serial No. 11 / 837,529 (filed on August 12, 2007). U.S. Patent 7,903,339 ). US Patent Application Serial No. 13 / 913,402, filed June 8, 2013, is a CIP of 13 / 014,398 filed January 26, 2011, which is a CIP of 12 / 793,772 filed June 4, 2010, which issued a CIP of U.S. Pat 12 / 686,861 filed January 13, 2010 ( U.S. Patent 8,593,728 ), which is a CIP of the 12 / 389,256 ( U.S. Patent 8,329,247 ), all of which are incorporated by reference in their entirety.

FIELD OF THE INVENTION

The present invention relates to multilayer stacked structures having protective coatings thereon, and more particularly to multi-layered hybrid stacked structures having a protective coating thereon which exhibit minimal or imperceptible color shift when exposed to broadband electromagnetic radiation and viewed from different angles.

BACKGROUND OF THE INVENTION

Pigments of multilayer structures are known. In addition, pigments are also known which exhibit or provide an omnidirectional structural color with high chroma or saturation. However, such prior art pigments require as many as 39 thin film layers to obtain desired color properties.

It will be appreciated that the costs associated with producing thin multi-layered pigments are proportional to the number of layers required. As a result, the cost associated with producing high chroma omnidirectional structural colors using multilayer stacks of dielectric materials can be prohibitively high. Therefore, a high chroma omnidirectional structural color that requires a minimum number of thin film layers would be desirable.

In addition to the foregoing, it should be understood that when pigments are exposed to sunlight and particularly ultraviolet light, they may fade, exhibit color changes, etc. Accordingly, a pigment of omnidirectional, high chroma structural color which is weather resistant would also be desirable.

SUMMARY OF THE INVENTION

Provided is a hybrid pigment of an omnidirectional structural color. The pigment has a color visible to the human eye and has very little or no discernible color shift when exposed to broadband electromagnetic radiation (e.g., white light) and viewed from angles between 0 and 45 °.

The pigment is in the form of a multilayer stack, also referred to herein as a multilayer thin film, which reflects a reflection band of a predetermined full half width (FWHM) of less than 300 nm. In addition, the reflection band has a predetermined color shift of less than 30 ° in an a * b * color chart using the CIELAB color space, when the pigment is exposed to broad band electromagnetic radiation and viewed from angles between 0 and 45 °.

The multilayer stack has a reflective core layer and at least two high refractive index (n _h ) layers. One of the n _h layers may be a dry deposited n _h dielectric layer extending over the reflective core layer, and one of the layers may be a dry deposited absorber layer extending over the dry deposited n _h dielectric layer. The multilayer stack also includes an outer protective layer, which may be in the form of a wet-deposited outer n "_h" oxide layer. In some cases, the wet-deposited outer n "_h" layer will cover the dry-deposited absorber layer and be in direct contact with it and may or may not completely surround or sheath the reflector core layer and at least two n "_h" layers.

The reflective core layer may be a metallic reflector core layer having a thickness between 30-200 nm. In some cases, the metallic core reflector layer is made of at least one of Al, Ag, Pt, Cr, Cu, Zn, Au, Sn, and alloys thereof.

The dry-deposited dielectric layer is n _h of at least one of CeO _2, Nb ₂ O _5, SiN, SnO _2, SnS, TiO _2, ZnO, ZnS, and _ZrO2, or made of a mixture comprising at least one of CeO _2, Nb ₂ O ₅ , SiN, SnO ₂ , SnS, TiO ₂ , ZnO, ZnS and ZrO ₂ . In addition, the dry deposited n _h dielectric layer has a thickness between 0.1 QW-4.0QW for a desired control wavelength, the desired control wavelength being a center wavelength for a desired color reflection band. The dry deposited absorber layer is made of at least one of Cr, Cu, Au, Sn, alloys thereof, amorphous Si, Fe ₂ O _3, and the like, and may have a thickness between 2-30 nm. The wet-deposited outer n _H oxide layer is made of at least one of CeO ₂ , Nb ₂ O ₅ , SnO ₂ , TiO ₂ , ZnO, and ZrO ₂ , and may have a thickness between 5-200 nm.

In some cases, the multilayer reflector has an average core layer and a pair of dry deposited dielectric _h n layers, which are arranged opposite one another and delimit the reflective core layer. In addition, a pair of absorber layers may be arranged opposite one another and delimit the pair of dry deposited dielectric layers n _h. Also, the wet deposited outer n "_h" oxide layer may extend over outer surfaces of the pair of absorber layers.

The hybrid omnidirectional structural color pigment has a thickness of less than 2.0 μm and in some cases has a thickness of less than 1.5 μm. The pigment, and thus the multilayer stack, may also have less than 10 layers in total, and in some cases may have less than 8 layers in total.

Also provided is a method of making an omnidirectional structural color pigment. The method includes fabricating the multilayer stack discussed above by providing a reflective core layer and dry depositing an n _h dielectric layer extending over the reflective core layer. Moreover, the method includes Trockenabscheiden an absorber layer extending over the dielectric layer _h n, and _h n Nassabscheiden an outer oxide layer, which extends over the absorber layer.

BRIEF DESCRIPTION OF THE FIGURES

1 Figure 3 is a schematic representation of a multi-layer stack of omnidirectional structural paint made of a dielectric layer, a selective absorbing layer (SAL) and a reflector layer;

2A is a schematic representation of zero or near zero electric field point within a ZnS dielectric layer exposed to 500 nm electromagnetic radiation (EMR);

2 B is a plot of the absolute value of the electric field squared (| E | ² ) versus the thickness of the in 2A shown ZnS dielectric layer when exposed to an EMR with wavelengths of 300, 400, 500, 600 and 700 nm;

3 Fig. 12 is a schematic representation of a dielectric layer extending over a substrate or reflector layer exposed to electromagnetic radiation at an angle θ relative to a normal to the outer surface of the dielectric layer;

4 Fig. 12 is a schematic representation of a ZnS dielectric layer having a Cr absorber layer disposed at the zero or near zero electric field point within the incident ZnS dielectric layer having a wavelength of 434 nm;

5 Figure 3 is a graph of percent reflection versus reflected EMR wavelength for a multilayer stack without a Cr absorber layer (e.g. 2A ) and a multilayer stack with a Cr absorber layer (e.g. 4 ) exposed to white light;

6A FIG. 12 is a plot of first harmonic and second harmonic of a ZnS dielectric layer extending over an Al reflector layer (eg, FIG. 2A );

6B FIG. 12 is a graph of percent reflection versus reflected EMR wavelength for a multilayer stack having a ZnS dielectric layer extending over an Al reflector layer and a Cr absorber layer disposed within the ZnS dielectric layer, FIG. that in 6A be absorbed second harmonic shown;

6C FIG. 12 is a graph of percent reflection versus reflected EMR wavelength for a multilayer stack having a ZnS dielectric layer extending over an Al reflector layer and a Cr absorber layer disposed within the ZnS dielectric layer, FIG. that in 6A absorbed first harmonic shown;

7A Figure 12 is a plot of an electric field squared versus thickness of the dielectric layer showing the angular dependence of the electric field of a Cr absorber layer for incident light exposure at 0 and 45 degrees;

7B Figure 12 is a plot of% absorption through a Cr absorber layer versus the reflected EMR wavelength when exposed to white light at angles of 0 and 45 ° relative to the normal of the outer surface (where 0 ° is the normal to the surface);

8A Fig. 10 is a schematic representation of a multilayer stack of red omnidirectional structural paint according to an embodiment disclosed herein;

8B is a graph of the percent absorption of in 8A shown Cu absorber layer over the reflected EMR wavelength for loading the in 10A shown multilayer stack with white light at angles of incidence of 0 and 45 °;

9 FIG. 12 is a graphical comparison of computation / simulation data and percent reflection versus reflected EMR wavelength experimental data for concept verification of the multilayer stack of red omnidirectional structural color exposed to white light at an incidence angle of 0 °;

10 Figure 4 is a plot of percent reflection versus wavelength for a multilayer stack of omnidirectional structural color in accordance with an embodiment disclosed herein;

11 Figure 4 is a plot of percent reflection versus wavelength for a multilayer stack of omnidirectional structural color in accordance with an embodiment disclosed herein;

12 Figure 4 is a plot of percent reflection versus wavelength for a multilayer stack of omnidirectional structural color in accordance with an embodiment disclosed herein;

13 Figure 4 is a plot of percent reflection versus wavelength for a multilayer stack of omnidirectional structural color in accordance with an embodiment disclosed herein;

14 FIG. 12 is a graphical representation of a portion of an a * b * color chart using CIELAB color space comparing the chroma and hue shift between a conventional color and a color made from pigments in accordance with an embodiment disclosed herein (sample (FIG. b));

15 Figure 3 is a schematic representation of a multilayer stack of omnidirectional structural paint according to an embodiment disclosed herein;

16 Figure 3 is a schematic representation of a five-layered pigment of omnidirectional structural color having a protective coating according to an embodiment disclosed herein;

17 Fig. 12 is a schematic representation of a protective coating containing two or more layers according to an embodiment disclosed herein;

18 Figure 3 is a schematic representation of a multilayer stack of omnidirectional structural paint according to an embodiment disclosed herein; and

19 Figure 10 is a schematic representation of a seven-layered pigment of omnidirectional structural color having a protective coating according to an embodiment disclosed herein.

DETAILED DESCRIPTION OF THE INVENTION

Provided is a pigment of an omnidirectional structural color. The omnidirectional structural ink is in the form of a multilayer stack (also referred to herein as a multilayer thin film) that reflects a narrow band of electromagnetic radiation in the visible spectrum and has little or no discernible color shift when the multilayer stack is out through the human eye Angles between 0 to 45 degrees is considered. Technically speaking, the multilayer stack reflects a narrow band of visible electromagnetic radiation having a width of less than 300 nm when exposed to white light. In addition, the narrow band of reflected visible light shifts less than 30 ° in an a * b * color chart using the CIELAB color space when the pigment is viewed from angles between 0 to 45 degrees relative to the normal of an outer surface of the multilayer stack becomes.

The multilayer stack has a reflector core layer, a high refractive index (n _h ) dielectric layer extending over the reflector core layer, an absorber layer extending over the n _h dielectric layer, and an n _h outer protective layer extending over the absorber layer. In some cases, the narrow band of reflected electromagnetic radiation has an FWHM defined below less than 200 nm and in other cases less than 150 nm. The multilayer stack may also have a color shift of less than 20 ° and in some cases less than 15 ° in the a * b * color chart.

Another measure of the color shift is a shift of a center wavelength of the narrow reflection band. As such, a center wavelength of the narrow band of reflected visible light shifts less than 50 nm, preferably less than 40 nm, and more preferably less than 30 nm, when the multilayer stack is exposed to broad band electromagnetic radiation and from angles between 0 and 45 degrees relative to that Normal is considered an outer surface of the multilayer stack. Also, the multilayer stack may or may not have a separate reflected band of electromagnetic radiation in the UV and / or IR region.

The total thickness of the multilayer stack is less than 2 μm, preferably less than 1.5 μm and more preferably less than 1.0 μm. As a result, the multilayered stack can be used as a color pigment in thin film color coatings.

The multilayer stack may also include a reflector core layer over which the first layer and the second layer extend, and the reflector core layer may be made of metals such as Al, Ag, Pt, Cr, Cu, Zn, Au, Sn, alloys thereof, and be made of the same. The reflector core layer typically has a thickness between 30-200 nm.

The first layer is made of a dielectric material _h n, and the second layer is made of an absorbent material. The dielectric n _h material may be CeO ₂ , Nb ₂ O ₅ , SiN, SnO ₂ , SnS, TiO ₂ , ZnO, ZnS and ZrO ₂ include, but are not limited to. The absorbing material may include selectively absorbing materials such as Cu, Au, Zn, Sn, alloys thereof, and the like, or may alternatively include colored dielectric materials such as Fe ₂ O ₃ , Cu ₂ O, combinations thereof, and the like. The absorbent material may also be a non-selective absorbing material such as Cr, Ta, W, Mo, Ti, Ti-nitride, Nb, Co, Si, Ge, Ni, Pd, V, iron oxides, combinations or alloys thereof and the like be. The outer protective layer may include, but is not limited to, CeO ₂ , Nb ₂ O ₅ , SnO ₂ , TiO ₂ , ZnO, and ZrO ₂ .

The thickness of the dielectric layer may be between 0.1 _h n be QW QW 4.0 for a desired wavelength control. The thickness of an absorbing layer made of selectively absorbing material is between 20-80 nm, whereas the thickness of an absorbing layer made of a non-selective absorbing material is between 5-30 nm. The thickness of the outer protective layer may be between 5-200 nm.

The multilayer stack may have a narrow reflected band of electromagnetic radiation that is in the form of a symmetrical peak within the visible spectrum. Alternatively, the narrow reflected band of electromagnetic radiation in the visible spectrum may be adjacent to the UV region, such that a portion of the reflected band of electromagnetic radiation, i. H. the UV section, invisible to the human eye. In another alternative, the reflected band of electromagnetic radiation may have a portion in the IR region such that the IR portion is not visible to the human eye.

Whether the visible band of electromagnetic radiation lying in the visible spectrum is adjacent to the UV region, the IR region, or has a symmetric peak within the visible spectrum, multilayer stacks disclosed herein have a narrow reflected band of electromagnetic radiation in the visible spectrum a slight, slight or imperceptible color shift. The slight or imperceptible color shift may be in the form of a slight shift of a center wavelength for a narrow reflected band of electromagnetic radiation. Alternatively, the slight or imperceptible color shift may be in the form of a slight shift of a UV-side boundary or IR-side boundary of a reflected band of electromagnetic radiation adjacent to the IR region or UV region, respectively. Such a slight shift of a center wavelength, UV-side boundary and / or IR-side boundary is typically less than 50 nm, in some cases less than 40 nm and in other cases less than 30 nm when the multilayer stack of angles between 0 and 45 degrees relative to the normal of an outer surface of the multilayer stack. The slight or imperceptible color shift may also be in the form of a slight hue shift in an a * b * color chart using the CIELAB color space. For example, in some cases, the hue shift for the multilayer stack is less than 30 °, preferably less than 25 °, more preferably less than 20 °, even more preferably less than 15 °, and even more preferably less than 10 °.

In addition to the above, the omnidirectional structural paint may be in the form of a multi-layered stack in the form of a plurality of pigment particles having the outer protective coating thereon, e.g. As a weather-resistant coating, are present. The outer protective coating may include one or more n "_h" oxide layers that reduce the relative photocatalytic activity of the pigment particles. In some cases, the outer protective coating includes a first oxide layer and a second oxide layer. Moreover, the first oxide layer and / or the second oxide layer may be a hybrid oxide layer, ie, an oxide layer that is a combination of two different oxides.

A method for producing the pigment of an omnidirectional structural color may or may not involve the use of an acid, an acidic compound, an acidic solution, and the like. In other words, the plurality of pigment particles of an omnidirectional structural color may or may not be treated in an acidic solution. Additional teachings and details of the pigment of an omnidirectional structural paint and a method of making the pigment will be discussed later in this document.

With reference to 1 a design is shown in which a first layer DL ₁ of dielectric material extends over an underlying reflector layer (RL) and a selectively absorbing layer SAL extends over the DL ₁ layer. In addition, another DL ₁ may be provided or may not layer and extending over the selectively absorbing layer. Also in the figure is one Showing that all of the incident electromagnetic radiation from the multilayer structure is either reflected or selectively absorbed.

Such in 1 illustrated design corresponds to another approach that is used to design and manufacture a desired multilayer stack. In particular, a thickness of zero or near zero energy point is used and discussed below for a dielectric layer.

For example 2A a schematic representation of a dielectric ZnS layer extending over an Al reflector core layer. The dielectric ZnS layer has a total thickness of 143 nm, and for incident electromagnetic radiation having a wavelength of 500 nm, there is an energy point of zero or near zero at 77 nm. In other words, the ZnS dielectric layer at a distance of 77 nm from the Al reflector layer for incident electromagnetic radiation (EMR) having a wavelength of 500 nm has an electric field of zero or near zero. In addition, looks 2 B for a series of different incident EMR wavelengths, plot the energy field over the ZnS dielectric layer. As shown in the graph, the dielectric layer has a zero electric field for the wavelength of 500 nm at a thickness of 77 nm, but for EMR wavelengths of 300, 400, 600 and 700 nm has a non-zero electric field in the Thickness of 77 nm.

Illustrated with respect to the calculation of an electric field point of zero or near zero 3 a dielectric layer 4 with a total thickness 'D', an incremental thickness 'd' and a refractive index 'n' on a substrate or core layer 2 with a refractive index n _s . Incident light hits the outer surface 5 the dielectric layer 4 with an angle θ relative to the line 6 on that to the outer surface 5 is perpendicular, and is from the outer surface 5 reflected at the same angle θ. Incident light passes through the outer surface 5 and in the dielectric layer 4 with an angle θ _F relative to the line 6 transmitted and hits with an angle θ _s on the surface 3 the substrate layer 2 on.

und für eine p-Polarisation als:

wobei k = 2π / λ und λ eine zu reflektierende gewünschte Wellenlänge ist. Auch gilt α = n_s, sinθ_s, wobei ,s' dem Substrat in 5 entspricht, und ε ~(z) die Dielektrizitätskonstante der Schicht als eine Funktion von z ist. Demzufolge gilt |E(d)|² = |u(z)|²exp(2ikαy)|_z=d (3) für eine s-Polarisation und

für eine p-Polarisation.For a single dielectric layer, θ _s = θ _F , and the energy / electric field (E) can be expressed as E (z) when z = d. From the Maxwell equations, the electric field for s-polarization can be expressed as:

and for a p-polarization as:

in which k = 2π / λ and λ is a desired wavelength to be reflected. Also, α = n _s , sin θ _s , where, s' is the substrate in 5 corresponds, and ε ~ (z) the dielectric constant of the layer is a function of z. Consequently, applies | E (d) | ² = | u (z) | ² exp (2ikαy) | _{z = d} (3) for a s polarization and

for a p-polarization.

It is understood that a variation of the electric field along the Z-direction of the dielectric layer 4 can be estimated by calculating the unknown parameters u (z) and v (z), where it can be shown that:

und v(z)|_z=d = iqu|_z=0sinφ + v|_z=0cosφ = iqsinφ + q_scosφ (12) Normally, i 'is the square root of -1. Using the boundary conditions u | _{z = 0} = 1, v | _{z = 0} = q _s and the following relations: q _s = n _s cos θ _s for an s polarization (6) q _s = n _s / cos θ _s for a p-polarization (7) q = ncosθ _F for an s-polarization (8) q = n / cosθ _F for a p-polarization (9) φ = k · n · d cos (θ _F ) (10) u (z) and v (z) can be expressed as:

and v (z) | _{z = d} = iqu | _{z = 0} sinφ + v | _{z = 0} = cos iqsinφ q + _s cos (12)

für eine s-Polarisation mit φ = k·n·dcos(θ_F), und:

gilt für eine p-Polarisation, wobei gilt: α = n_ssinθ_s = nsinθ_F (15)

Therefore:

for an s-polarization with φ = k · n · d cos (θ _F ), and:

applies to a p-polarization, where: α = n _s sin θ _s = n sin θ _F (15)

was es ermöglicht, nach der Dicke ,d' aufzulösen, d. h. der Position oder Stelle innerhalb der dielektrischen Schicht, wo das elektrische Feld null ist.Thus, for a simple situation, where θ _F = 0 or a perpendicular incidence, φ = k · n · d and α = 0:

which makes it possible to resolve by thickness, d ', ie the position or location within the dielectric layer where the electric field is zero.

With reference to 4 Equation 19 was used to calculate the electric field point from zero or near zero in the 2A ZnS dielectric layer when exposed to an EMR having a wavelength of 434 nm. The zero or near zero electric field point was calculated to be 70 nm (instead of 77 nm for a wavelength of 500 nm). In addition, at the thickness or the distance of 70 nm from the Al reflector core layer, a 15 nm-thick Cr absorber layer was inserted to allow a ZnS-Cr interface of electric field of zero or near zero. Such an inventive structure allows light having a wavelength of 434 nm to pass through the Cr-ZnS interfaces, but absorbs light having a wavelength other than 434 nm. In other words, the Cr-ZnS interfaces have a zero or near electric field zero with respect to light having a wavelength of 434 nm, and thus 434 nm light passes through the interfaces. However, the Cr-ZnS interfaces do not have zero or near zero electric field for light having a wavelength other than 434 nm, and thus such light is absorbed by the Cr absorber layer and / or the Cr-ZnS interfaces and not by reflected the Al reflector layer.

It is understood that a certain percentage of light will pass through the Cr-ZnS interface within +/- 10 nm of the desired 434 nm. However, it is also understood that such a narrow band of reflected light, e.g. 434 +/- 10 nm yet provides a sharp structural color to a human eye.

The result of the Cr absorber layer in the multilayer stack in FIG 4 is in 5 Figure 4 illustrates where the percent reflection over the reflected EMR wavelength is shown. As shown by the dashed line, the in 4 At about 400 nm, there is a narrow reflection peak, but a much broader peak is at about 550+ nm. In addition, a considerable amount of light is still reflected in the wavelength range of 500 nm. As a result, there is a double peak which prevents the multilayer stack from having or having a structural color.

In contrast, the solid line in 5 the in 4 shown structure with the existing Cr absorber layer. As shown in the figure, there is a sharp peak at about 434 nm, and for wavelengths greater than 434 nm, the Cr absorber layer causes a sharp drop in reflectance. It is understood that the sharp peak represented by the solid line appears visually as sharp / structural color. Also illustrated 5 , where the width of a reflection peak or band is measured, ie the width of the band is measured at 50% reflection of the maximum reflected wavelength, also called full width at half maximum (FWHM).

Regarding the omnidirectional behavior of the 4 The thickness of the ZnS dielectric layer may be designed or adjusted such that only the first harmonics of reflected light are provided. It is understood that this is sufficient for a "blue" color, but the generation of a "red" color requires additional considerations. For example, control of angle independence for red color is difficult because thicker dielectric layers are required, which in turn results in a highly harmonic design, ie, the presence of the second and possible third harmonics is unavoidable. Also, the color space of the dark red color is very narrow. As a result, a multilayer stack of a red color has a higher angular variance.

In order to overcome the higher angular variance for red color, the present application discloses a unique and novel design / structure that enables a red color that is angular independent. For example, illustrated 6A a dielectric layer having first and second harmonics for incident white light when an outer surface of the dielectric layer is viewed from 0 and 45 degrees relative to the normal of the outer surface. As shown by the graph, a low angle dependence (small Δλ _c ) is provided by the thickness of the dielectric layer, but such a multilayer stack has a combination of blue color (1st harmonic) and red color (2nd harmonic) is therefore not suitable for a desired "exclusively red" color. Therefore, the concept / structure of using an absorber layer to absorb an undesired harmonic series has been developed. 6A Figure 12 also illustrates an example of the position of the reflection band mean wavelength (λ _c ) for a given reflection peak and the distribution or shift of the center wavelength (Δλ _c ) when the sample is viewed from 0 and 45 degrees.

Referring to 6B will the in 6A is absorbed with a Cr absorber layer at the appropriate thickness of the dielectric layer (e.g., 72 nm), and a sharp blue color is provided. Also illustrated 6C in that a red color is provided by absorbing the first harmonic with the Cr absorber at a different thickness of the dielectric layer (e.g., 125 nm). However illustrated 6C Also, that the use of the Cr absorber layer can still lead to more than a desired angle dependence by the multilayer stack, ie a larger Δλ _c than desired.

It will be understood that the relatively large shift of λ _c for the red color compared to the blue color is due to the fact that the dark red color space is very narrow, and due to the fact that the Cr absorber layer has wavelengths associated with zero absorbed different electric field, ie no light is absorbed when the electric field is zero or near zero. Accordingly illustrated 7A in that the zero or non-zero point is different for light wavelengths at different angles of incidence. Such factors lead to the in 7B shown angle-dependent absorption, ie the difference of the 0 ° and 45 ° absorption curves. Thus, to further refine the design of the multilayer stack and the angular independence performance, an absorber layer is used, e.g. B. blue light is absorbed regardless of whether the electric field is zero or not.

In particular shows 8A a multilayer stack having a Cu absorber layer instead of a Cr absorber layer extending over a ZnS dielectric layer. The results of using such a "colored" or "selective" absorber layer are in 8B shown a much "narrower" grouping of the 0 ° and 45 ° absorption lines for the in 8A shows shown multilayer stack. As a result, a comparison between 8B and 7B the significant improvement in absorption angle independence when a selective absorber layer is used instead of a non-selective absorber layer.

Based on the above, a concept proof multilayer stack structure was designed and manufactured. In addition, calculation / simulation results and actual experimental data for the concept proof sample were compared. In particular, and as represented by the graph in FIG 9 shown a sharp red color was produced (wavelengths greater than 700 nm are typically not seen by the human eye), and there was a very good agreement between the calculation / simulation and the experimental light data obtained from the actual sample. In other words, calculations / simulations may be used and / or used to simulate the results of multilayer stack designs according to one or more of the prior art embodiments and / or multilayer stacks disclosed herein.

A list of simulated and / or actually produced multilayer stack samples is provided in Table 1 below. As shown in the table, those disclosed herein include inventive designs at least 5 different layered structures. In addition, the samples were simulated and / or made from a wide range of materials. Samples were provided with high chroma, low hue shift (Δh), and excellent reflection. Also, the three- and five-layered samples had a total thickness between 120-200 nm; the seven-layered samples had a total thickness between 350-600 nm; the nine-layered samples had a total thickness between 440-500 nm; and the eleven-layered samples had a total thickness between 600-660 nm. Table 1 Avg. Chroma (0-45) Δh (0-65) Max. Reflection sample name 3 layers 90 2 96 3-1 5 layers 91 3 96 5-1 7 layers 88 1 92 7-1 91 3 92 7-2 91 3 96 7-3 90 1 94 7-4 82 4 75 7-5 76 20 84 7-6 9 layers 71 21 88 9-1 95 0 94 9-2 79 14 86 9-3 90 4 87 9-4 94 1 94 9-5 94 1 94 9-6 73 7 87 9-7 11 layers 88 1 84 11-1 92 1 93 11-2 90 3 92 11-3 89 9 90 11-4

Referring to 10 For example, a plot of percent reflection versus reflected EMR wavelength for an omnidirectional reflector when exposed to white light at angles of 0 and 45 degrees relative to the normal of the outer surface of the reflector is shown. As shown by the illustration, both curves of 0 ° and 45 ° represent a very low reflection, e.g. B. less than 20%, which is provided by the omnidirectional reflector for wavelengths greater than 500 nm. However, as shown by the curves, the reflector provides a large increase in reflection at wavelengths between 400-500 nm and reaches a maximum of about 90% at 450 nm. It is understood that the portion or region of the graph is on the left Side (UV side) of the curve represents the UV portion of the reflection band provided by the reflector.

The sharp increase in reflection provided by the omnidirectional reflector is characterized by an IR-side boundary of each curve extending from a low-reflection portion at wavelengths above 500 nm to a high-reflectance portion, e.g. B.> 70%, extends. An IR side boundary linear section 200 is inclined at an angle (β) greater than 60 ° relative to the x axis, has a length L of about 50 on the reflection axis, and an inclination of 1.2. In some cases, the linear portion is inclined at an angle greater than 70 ° relative to the x axis, while in other cases β is greater than 75 °. Also, the reflection band has a visible FWHM of less than 200 nm and in some cases a visible FWHM of less than 150 nm and in other cases a visible FWHM of less than 100 nm. In addition, the center wavelength λ _c for the in 10 illustrated visible reflection band is defined as the wavelength equidistant between the IR-side boundary of the reflection band and the UV limit of the UV spectrum at the visible FHWM.

The term "visible FWHM" refers to the width of the reflection band between the IR side boundary of the curve and the boundary of the UV spectrum region, beyond which reflection provided by the omnidirectional reflector is not visible to the human eye. In this way, the inventive designs and multilayer stacks disclosed herein utilize the non-visible UV portion of the electromagnetic radiation spectrum to provide a sharp or structural color. In other words, the omnidirectional reflectors disclosed herein may utilize the non-visible UV portion of the electromagnetic radiation spectrum to provide a narrow band of reflected visible light, despite the fact that the reflectors may reflect a much broader band of electromagnetic radiation propagating in them extends the UV range.

With reference to 11 For example, when viewed at 0 ° and 45 °, a generally symmetrical reflection band provided by a multilayer stack according to an embodiment disclosed herein is shown. As illustrated in the figure, the reflection band provided by the multilayer stack has a central wavelength λ _c (0 °) when viewed at 0 ° and a central wavelength λ _c (45 °) when viewed at 45 °. Also, the center wavelength shifts less than 50 nm when the multilayer stack is viewed at angles between 0 and 45 °, ie, Δλ _c (0-45 °) <50 nm. In addition, the FWHM is both the reflection band of 0 ° and of the reflection band of 45 ° smaller than 200 nm.

12 Figure 12 shows a plot of percent reflection versus reflected EMR wavelength for another omnidirectional reflector design when exposed to white light at angles of 0 and 45 degrees relative to the normal of the outer surface of the reflector. As shown by the illustration, both curves of 0 ° and 45 ° represent a very low reflection, e.g. B. less than 10%, which is provided by the omnidirectional reflector for wavelengths less than 550 nm. However, as shown by the curves, the reflector provides a large increase in reflection at wavelengths between 560-570 nm and reaches a maximum of about 90% at 700 nm. It is understood that the portion or region of the graph is on the right Side (IR side) of the curve represents the IR section of the reflection band provided by the reflector.

The sharp increase in reflection provided by the omnidirectional reflector is characterized by a UV-side boundary of each curve extending from a low-reflection portion at wavelengths below 550 nm to a high-reflectance portion, e.g. B.> 70%, extends. A linear portion 200 of the UV-side boundary is inclined at an angle (β) greater than 60 ° relative to the x-axis, has a length L of about 40 on the reflection axis, and an inclination of 1.4. In some cases, the linear portion is inclined at an angle greater than 70 ° relative to the x-axis, while in other cases β is greater than 75 °. Also, the reflection band has a visible FWHM of less than 200 nm and in some cases a visible FWHM of less than 150 nm and in other cases a visible FWHM of less than 100 nm. In addition, the center wavelength λ _c for the in 12 illustrated visible reflection band defined as the wavelength equidistant between the UV-side boundary of the reflection band and the IR-boundary of the IR spectrum at the visible FHWM.

It will be understood that the term "visible FWHM" refers to the width of the reflection band between the UV boundary of the curve and the boundary of the IR spectrum region, beyond which reflection provided by the omnidirectional reflector to the human eye is not visible. In this way, the inventive designs and multilayer stacks disclosed herein utilize the non-visible IR portion of the electromagnetic radiation spectrum to provide a sharp or structural color. In other words, the omnidirectional reflectors disclosed herein utilize the non-visible IR portion of the electromagnetic radiation spectrum to provide a narrow band of reflected visible light, despite the fact that the reflectors can reflect a much broader band of electromagnetic radiation propagating into the IR range extends.

Referring to 13 Figure 4 is a plot of percent reflection versus wavelength for another seven-layered omnidirectional reflector design when exposed to white light at angles of 0 and 45 degrees relative to the outer surface of the reflector. In addition, a definition or characterization of omnidirectional properties provided by omnidirectional reflectors disclosed herein is shown. In particular, and when the reflection band provided by an inventive reflector has a maximum, that is, has a peak as shown in the figure each curve has a center wavelength (λ _c ) defined as the wavelength having or experiencing maximum reflection. The term maximum reflected wavelength can also be used for λ _c .

As in 13 Shown is a displacement or displacement of λ _c when an outer surface of the omnidirectional reflector is viewed from a 45 ° angle (λ _c (45 °)), e.g. When the outer surface is inclined at 45 ° relative to a human eye looking at the surface, compared to when the surface is viewed from an angle of 0 ° (λ _c (0 °)), that is, perpendicular to the surface. This shift of λ _c (Δλ _c ) provides a measure of the omnidirectional nature of the omnidirectional reflector. Normally, zero displacement, that is, no displacement at all, would be a perfectly omnidirectional reflector. However, omnidirectional reflectors disclosed herein may provide a Δλ _c of less than 50 nm, which may appear to the human eye as if the color of the surface of the reflector has not changed, and thus, in practical terms, the reflector is omnidirectional. In some cases, omnidirectional reflectors disclosed herein may provide a Δλ _c of less than 40 nm, in other cases a Δλ _c of less than 30 nm and in still other cases a Δλ _c of less than 20 nm and in yet other cases a Δλ _c of less than 15 nm. Such a shift of Δλ _c can be determined by a plot of the actual reflection versus wavelength for a reflector and / or alternatively by modeling the reflector if the materials and layer thicknesses are known.

Another definition or characterization of the omnidirectional properties of a reflector can be determined by shifting a lateral boundary for a given set of angular reflection bands. For example, and with reference to 10 represents a shift or displacement of an IR-side boundary (ΔS _IR ) for reflection from an omnidirectional reflector viewed from 0 ° (S _IR (0 °)) compared to the IR side boundary for reflection by the same reflector , which is viewed from 45 ° (S _IR (45 °)), provides a measure of the omnidirectional nature of the omnidirectional reflector. Moreover, the use of ΔS _IR as a measure of omnidirectionality over the use of Δλ _{c may be} preferred, e.g. For example, for reflectors that have a reflection band similar to that in FIG 10 or 12 shown, ie, a reflection band extending in the UV or IR region of EMR. It is understood that the shift in the IR-side limit (ΔS _IR ) at the visible FWHM is measured and / or can be measured.

With reference to 12 represents a shift or shift of a UV-side limit (ΔS _UV ) for reflection from an omnidirectional reflector viewed from 0 ° (S _UV (0 °)) compared to the IR-side limit for reflection by the same reflector _Being viewed from 45 ° (S _UV (45 °)) provides a measure of the omnidirectional nature of the omnidirectional reflector. It is understood that the shift in the UV-side limit (ΔS _UV ) at the visible FWHM is measured and / or can be measured.

Normally, a shift of zero, ie no displacement at all (ΔS _i = 0 nm, i = IR, UV) would characterize a perfectly omnidirectional reflector. However, omnidirectional reflectors disclosed herein may provide a ΔS _i of less than 50 nm, which may appear to the human eye as if the color of the surface of the reflector has not changed, and thus, in practical terms, the reflector is omnidirectional. In some cases omnidirectional reflectors disclosed herein may provide a ΔS _i of less than 40 nm, in other cases a ΔS _i of less than 30 nm and in still other cases a ΔS _i of less than 20 nm and in yet other cases a ΔS _i less than 15 nm. Such a shift in ΔS _i can be determined by a plot of the actual reflection versus wavelength for a reflector and / or alternatively by modeling the reflector if the materials and layer thicknesses are known.

The shift of an omnidirectional reflection can also be measured by a slight hue shift. For example, the hue shift of pigments made of multilayer stacks according to an embodiment disclosed herein is 30 ° or less, as in FIG 14 (eg, Δθ ₁ and Δθ ₃ ), and in some cases, the hue shift is 25 ° or less, preferably less than 20 °, more preferably less than 15 °, and even more preferably less than 10 °. In contrast, conventional pigments have a hue shift of 45 ° or more (eg, Δθ ₂ and Δθ ₄ ). It is understood that the hue shift associated with Δθ ₁ generally corresponds to a red color, but the small color shift is relevant to any color reflected from a hybrid pigment of omnidirectional structural color disclosed herein. For example, the in 14 shown slight hue shift Δθ ₃ in general of a blue color provided by an exemplary hybrid pigment of an omnidirectional structural color, whereas the relatively large hue shift of a conventional blue pigment is represented by Δθ ₄ .

A schematic representation of an omnidirectional multilayer stack according to another embodiment disclosed herein is shown in FIG 15 with reference number 10 shown. The multilayer stack 10 has a first layer 110 and a second layer 120 on. An optional reflector layer 100 can be included. Exemplary materials for the reflector layer 100 , which is sometimes referred to as a reflector core layer, may include, but is not limited to, Al, Ag, Pt, Cr, Cu, Zn, Au, Sn, and alloys thereof. As a result, the reflector layer 100 a metallic reflector layer, but this is not required. In addition, exemplary thicknesses for the core reflector layer are in the range between 30 to 200 nm.

A symmetric pair of layers may be on one of the reflector layers 100 located opposite side, ie the reflector layer 100 may comprise a further first layer, which is opposite to the first layer 110 is arranged so that the reflector layer 100 sandwiched between a pair of first layers. In addition, another second layer 120 opposite to the reflector layer 100 be arranged so that a five-layer structure is provided. Therefore, it should be understood that the discussion of the multilayer stacks provided herein also includes the possibility of a mirror structure with respect to one or more middle layers. As a result, can 15 to illustrate one half of a five-layer multilayer stack.

The first shift 110 may be a high refractive index (n _h ) dielectric layer which is deposited dry. For the purposes of the present disclosure, the term high refractive index material refers to a material having a refractive index greater than or equal to 2.0. Also, the term "dry deposited" refers to a layer that has been deposited and / or formed using a dry deposition technique known to those skilled in the art, such as chemical vapor deposition (CVD) and physical vapor deposition (PVD). Also, the term "dry deposition" refers to the deposition of a layer using a dry deposition technique known to those skilled in the art.

Exemplary materials for the dry deposited dielectric layer n _h 110 include, but are not limited to, CeO ₂ , Nb ₂ O ₅ , SiN, SnO ₂ , SnS, TiO ₂ , ZnO, ZnS, and ZrO ₂ . Moreover, / may the dry deposited (n) dielectric (n) n _h layer (s) have a thickness between 0.1 QW and 4.0 QW for a desired control shaft length, the desired control wavelength is a center wavelength of a reflection band of a desired color is. It should be understood that the term "QW" or "QW thickness" refers to a thickness that is one quarter of the desired control wavelength, ie, QW = λ _cw / 4, where λ _{cw is} the desired control wavelength.

The second layer 120 may be a dry deposited absorbent layer. Exemplary absorbent layer materials include, but are not limited to, Cr, Cu, Au, Sn, alloys thereof, amorphous Si and Fe ₂ O ₃ , and the thickness of the second layer 120 is preferably between 2 and 30 nm.

16 illustrates a pigment 10a a five-layered design with symmetrical layers, including an outer protective layer 200 extending over the reflector core layer 100 extend. The pigment 10a has, disposed opposite, a dry deposited dielectric n _h layer 110a and a dry-deposited absorbent layer 120a on. The outer protective layer 200 may be a wet-deposited protective layer and / or an n _h -Oxidschicht. It should be understood that the term "wet deposited" refers to a layer made using a wet-chemical technique known to those skilled in the art, such as sol-gel processing, layer-by-layer processing, spin-coating, and the like the like, deposited and / or formed. Exemplary examples of wet-deposited layer materials include CeO ₂ , Nb ₂ O ₅ , SnO ₂ , TiO ₂ , ZnO, and ZrO ₂ , and a thickness of such a layer may be in a range of 5-200 nm.

A non-exhaustive list of materials of which the dry deposited dielectric layer n _h and / or wet-deposited outer proactive _h n layers may be prepared in the following Table 2 is shown. Table 2 Materials with refractive index (visible range) Materials with refractive index (visible range) material refractive index material refractive index Germanium (Ge) 4.0-5.0 Chrome (Cr) 3.0 Tellurium (Te) 4.6 Tin sulfide (SnS) 2.6 Gallium antimonide (GaSb) 4.5-5.0 low porosity Si 2.56 Indium arsenide (InAs) 4.0 chalcogenide 2.6 Silicon (Si) 3.7 Cerium oxide (CeO ₂ ) 2.53 Indium phosphate (InP) 3.5 Tungsten (W) 2.5 Gallium arsenate (GaAs) 3.53 Gallium nitride (GaN) 2.5 Gallium phosphate (GaP) 3.31 Manganese (Mn) 2.5 Vanadium (V) 3 Niobium oxide (Nb ₂ O ₃ ) 2.4 Arsenic selenide (As ₂ Se ₃ ) 2.8 Zinc telluride (ZnTe) 3.0 CuAlSe ₂ 2.75 Chalcogenide glass + Ag 3.0 Zinc selenide (ZnSe) 2.5-2.6 Zinc sulfide (ZnS) 2.5-3.0 Titanium dioxide (TiO ₂ ) - sol-gel 2.36 Titanium dioxide (TiO ₂ ) - deposited in a vacuum 2.43 _SnO2 2.0 Hafnium oxide (HfO ₂ ) 2.0 Zinc sulfide (ZnS) 2.3 + i (0.015) Niobium oxide (Nb ₂ O ₅ ) 2.1 Titanium nitride (TiN) 1.5 + i (2.0) Aluminum (Al) 2.0 + i (15) Chrome (Cr) 2.5 + i (2.5) 4 Silicon nitride (SiN) 2.1 Niobium pentoxide (Nb ₂ O ₅ ) 2, Zirconium oxide (ZrO ₂ ) 2.36 Hafnium oxide (HfO ₂ ) 1.9-2.0

In some cases, the outer protective layer 200 from two in 17 illustrated wet deposited layers. For example, a wet-deposited layer 202 be a first n _H -Oxid, and a wet-deposited layer 204 may be a second n _H -Oxide. In addition, a single outer protective layer 200 , the layer 202 and / or the layer 204 be a n _h -Mischoxidschicht, which contains one or more n _h oxide (e).

It is understood that in 16 shown five-layer design an absorber layer 120 and 120a directly adjacent to or below the outer protective layer 200 having. In other words, a five-layered pigment produced by dry deposition has an outer absorbent layer and no outer dielectric layer before being coated with an outer protective layer. It is also understood that the outer protective layer can serve not only as a protective layer but also as a color-enhancing layer. For example, and for purposes of illustration only, the outer protective layer 200 merely serve as a protective layer and have no effect on the color of the pigment 10a to have. As a result, the entire color of the pigment 10a through the reflector core layer 100 , the dry deposited dielectric n _h layer 110 . 110a and the absorbing layer 120 . 120a provided. Alternatively, the outer protective layer 200 the pigment 10a with a certain color effect, such as an increase in the chroma of the pigment, a slight shift in the "color" exhibited by the pigment to the human eye, a slight increase in the omnidirectionality of the pigment (ie a reduced color shift), a slight decrease in pigmentation Omnidirectionality of the pigment and the like.

Referring to 18 is with reference numerals 20 another embodiment of an inventive multilayer stack shown. The multilayer stack 20 resembles the multilayer stack 10 with the exception of an additional absorbent layer 105 extending between the reflector core layer 100 and the dry deposited dielectric n _h layer 110 extends. Also similar to the one in 16 shown pigment 10a is in 19 a pigment 20a shown in which symmetrical layers 105a . 110a and 120a over the reflector core layer 100 extend and opposite to the layers 105 . 110 respectively. 120 are arranged. The pigment 20a also has the wet deposited outer n _H oxide protective layer 200 on.

Methods of making the multilayer stacks disclosed herein may be any method or process known to those skilled in the art, or methods that are not known to those skilled in the art. Typical known methods include wet processes, such as sol-gel processing, layer-by-layer processing, spin coating, and the like. Other known dry processes include a chemical vapor deposition process and a physical vapor deposition process such as sputtering, electron beam deposition, and the like.

The multilayered stacks disclosed herein may be used for almost any color application, such as pigments for paints, thin films applied to surfaces, and the like. In addition, those in the 16 and 18 illustrated pigments have omnidirectional structural color properties, as in 10 - 14 shown.

To better teach the invention without, however, limiting its scope in any way, examples of weather resistant pigments of omnidirectional structural color and process protocols for making such pigments are discussed below.

Protocol 1-5-layered pigments coated with a ZrO ₂ layer

Two grams of 5-layer pigments were suspended in 30 ml of ethanol in a 100 ml round bottom flask and stirred at 500 rpm at room temperature. A solution of 2.75 ml of zirconium butoxide (80% in 1-butanol) dissolved in 10 ml of ethanol was titrated in at 1 hour at a constant rate. At the same time, 1 ml of DI water, diluted in 3 ml of ethanol, was metered in. After the titration, the suspension was stirred for a further 15 minutes. The mixture was filtered, washed with ethanol and then isopropanol and dried at 100 ° C for 24 hours, or alternatively further annealed at 200 ° C for 24 hours, the final results being a 5-layer pigment with an in 16 were illustrated structure. If necessary, further annealing can be used at a higher temperature.

Protocol 2-5-layer pigments coated with a TiO ₂ layer

Two grams of 5-layer pigments were suspended in 30 ml IPA in a 100 ml round bottom flask and stirred at 40 ° C. Then, a solution of 2.5 ml of titanium ethoxide (97%) dissolved in 20 ml of IPA was titrated in a constant rate in 2.5 hours. At the same time, 2.5 ml DI water diluted in 4 ml IPA was metered in. After the titration, the suspension was stirred for a further 30 minutes. The mixture was then allowed to cool to room temperature, filtered, washed with IPA and dried at 100 ° C for 24 hours, or alternatively further annealed at 200 ° C for 24 hours, the final results being a 5-layer pigment with an in 16 were illustrated structure. If necessary, further annealing can be used at a higher temperature.

A summary of coatings, the method used to make a coating, the coating thickness, coating thickness uniformity and photocatalytic activity are shown in Table 3 below. Table 3. sample Core* layer material coating protocol Thickness (nm) uniformity Photocatalytic activity ** 1 P5 1. CeO ₂ *** 20 G 70% 2 P5 1. ZrO ₂ 1 80 G 29% 3 P5 1. TiO ₂ 2 80 G 36% 4 P5 1. TiO ₂ 2 80 G 27% Second ZrO ₂ -Al ₂ O ₃ *** 15 G * P5 = 5-layered pigment
** compared to uncoated 5-layer pigment
*** proprietary coating protocol

In view of the foregoing, Table 4 provides a listing of various oxide layers, substrates that can be coated, and coating thickness ranges included in the present teachings. Table 4. oxide substratum Coating thickness range (nm) SiO ₂ Mica, P5, metal, oxides 10-160 TiO ₂ Mica, P5, metal, oxides 20-100 ZrO ₂ Mica, P5, metal, oxides 20-100 Al ₂ O ₃ Mica, P5, metal, oxides 5-30 CeO ₂ Mica, P5, oxides ~ 5-40 SiO ₂ -Al ₂ O ₃ Mica, P5, oxides 20-100 ZrO ₂ -Al ₂ O ₃ Mica, P5, metal, oxides 10-50

In addition to the above, the pigments of an omnidirectional structural paint having a protective coating may be subjected to a surface treatment with organosilanes. For example, in an illustrative organosilane protocol treatment, 0.5 g of pigments coated with one or more of the protective layers discussed above were dissolved in 10 mL of a pH 4 EtOH / water (4: 1) solution 5.0 (adjusted by dilute acetic acid solution) suspended in a 100 ml round bottom flask. The slurry was sonicated for 20 seconds, then stirred at 500 rpm for 15 minutes. Next, 0.1-0.5 vol.% Of an organosilane agent was added to the slurry, and the solution was stirred at 500 rpm for further 2 hours. The slurry was then centrifuged or filtered using DI water, and the remaining pigments were redispersed in 10 ml of a 4: 1 EtOH / water solution. The pigment EtOH / water slurry was heated to 65 ° C, refluxing, and stirred at 500 rpm for 30 minutes. The slurry was then centrifuged or filtered using DI water and then IPA to produce a cake of pigment particles. Finally, the cake was dried at 100 ° C for 12 hours. If necessary, further annealing can be used at a higher temperature.

The organosilane protocol may employ any organosilane coupling agent known to those skilled in the art which illustratively comprises N- (2-aminoethyl) -3-aminopropyltrimethoxysilane (APTMS), N- [3- (trimethoxysilyl) propyl] ethylenediamine, 3-methacryloxypropyltrimethoxysilane (MAPTMS), N- [2 (vinylbenzylamino) ethyl] -3-aminopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane and the like.

The above examples and embodiments are for the purpose of illustration only, and variations, modifications and the like will be apparent to those skilled in the art and are still within the scope of the invention. Accordingly, the scope of the invention is defined by the claims and all equivalents thereof.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 8736959 [0001]
• US 8749881 [0001]
• US 7903339 [0001]
• US 8593728 [0001]
• US 8329247 [0001]

Claims (13)

A hybrid pigment of an omnidirectional structural ink, comprising: a multilayer stack comprising: a reflective core layer; a dry deposited high refractive index (n _h ) dielectric layer extending over the reflective core layer; a dry deposited absorber layer extending over the dielectric n _h layer; and a wet-deposited outer n _H oxide layer extending over the absorber layer; wherein the multilayer stack has a reflection band having a predetermined full width at half maximum (FWHM) of less than 300 nm and a predetermined hue shift of less than 30 ° when the multilayer stack is exposed to broad band electromagnetic radiation and from angles between 0 and 45 ° relative to that Normal is considered an outer surface of the multilayer stack. The hybrid pigment of an omnidirectional structural color according to claim 1, wherein the reflective core layer is a metallic core reflector layer having a thickness between 30-200 nm and is a metallic material consisting of at least one selected from the group consisting of Al, Ag, Pt, Cr, Cu, Zn, Au, Sn and alloys thereof are selected; and said dry deposited n _h dielectric layer is a dielectric material selected from at least one of CeO ₂ , Nb ₂ O ₅ , SiN, SnO ₂ , SnS, TiO ₂ , ZnO, ZnS and ZrO ₂ . An omnidirectional structural color hybrid pigment according to claims 1-2, wherein said dry deposited n _h dielectric layer has a thickness between 0.1 QW-4.0 QW for a desired control wavelength. An omnidirectional structural color hybrid pigment according to claims 1-3, wherein the dry deposited absorber layer is an absorber material selected from at least one selected from the group consisting of Cr, Cu, Au, Sn, alloys thereof, amorphous Si, and Fe ₂ O ₃ ; and has a thickness between 2-30 nm. A hybrid pigment of an omnidirectional structural color according to claims 1-4, wherein the wet-deposited outer n _H oxide layer is an oxide consisting of at least one selected from the group consisting of CeO ₂ , Nb ₂ O ₅ , SnO ₂ , TiO ₂ , ZnO and ZrO _{2 is} selected; and has a thickness between 5-200 nm. An omnidirectional structural color hybrid pigment according to claims 1-5, wherein the dry deposited n _h dielectric layer is a pair of n _h dielectric layers having the reflective core layer extending therebetween, wherein the dry deposited absorber layer comprises a pair of dry deposited absorber layers is the extending therebetween pair of dielectric layers and n _h at the wet deposited outer n _h oxide layer extends over the outer surfaces of the pair of dry deposited absorber layers. An omnidirectional structural ink hybrid pigment according to claims 1-6, wherein the multilayer stack has a thickness of less than 2.0 μm, and preferably less than 1.5 μm. An omnidirectional structural color hybrid pigment according to claims 1-7, wherein the multilayer stack has less than 10 layers, and preferably less than 8 layers. A method of producing a pigment of an omnidirectional structural color, the method comprising: preparing a multilayer stack by: providing a reflective core layer; Dry depositing a high refractive index (n _h ) dielectric layer extending over the reflective core layer; Dry depositing an absorber layer extending over the dielectric n _h layer; and wet-depositing an outer n "_h" oxide layer extending over the absorber layer; wherein the multilayer stack has a reflection band having a predetermined full width at half maximum (FWHM) of less than 300 nm and a predetermined hue shift of less than 30 ° when the multilayer stack is exposed to broad band electromagnetic radiation and from angles between 0 and 45 ° relative to that Normal is considered an outer surface of the multilayer stack. The method of claim 9, wherein the reflective core layer is a metallic core reflector layer having a thickness of between 30-200 nm made of a metallic material consisting of at least one selected from the group consisting of Al, Ag, Pt, Cr, Cu, Zn , Au, Sn and alloys thereof are selected therefrom; and the dry deposited n _h dielectric layer has a thickness between 0.1 QW-4.0QW for a desired control wavelength and is made of a dielectric material composed of at least one selected from the group consisting of CeO ₂ , Nb ₂ O ₅ , SiN, SnO ₂ , SnS, TiO ₂ , ZnO, ZnS and ZrO ₂ . The method of claims 9-10, wherein the dry deposited absorber layer has a thickness between 2-30 nm and is made of an absorber material consisting of at least one selected from the group consisting of Cr, Cu, Au, Sn, alloys thereof, amorphous Si and Fe ₂ O _{3 is} selected; and the wet-deposited outer n _H oxide layer has a thickness between 5-200 nm and is an oxide selected from at least one selected from the group consisting of CeO ₂ , Nb ₂ O ₅ , SnO ₂ , TiO ₂ , ZnO and ZrO ₂ is. The method of claims 9-11, wherein the multilayer stack has less than 10 layers, and preferably less than 8 layers. The method of claims 9-12, wherein the multilayer stack has a total thickness of less than 2.0 μm, and preferably less than 1.5 μm.

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