JP2016049777A - Red omnidirectional structural color made by metal and dielectric layers - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multilayer stack displaying a red structural color.SOLUTION: The multilayer stack includes: a core layer; a semiconductor layer extending across the core layer; and a dielectric layer extending across the semiconductor layer. The semiconductor layer absorbs more than 70% of incident white light that has a wavelength less than 550 nanometers (nm). In addition, the dielectric layer in combination with the core layer reflects 70% of the incident white light with a wavelength greater than 550 nm. In combination, the core layer, semiconductor layer and dielectric layer form an omnidirectional reflector that reflects a narrow band of visible electromagnetic radiation with a center wavelength of 550-700 nm and a width less than 200 nm and has a color shift less than 100 nm when the omnidirectional reflector is viewed from angles between 0° and 45°.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an omnidirectional structural color, in particular a red omnidirectional structural color provided by a multilayer stack having an absorber layer and a dielectric layer.

CROSS REFERENCE TO RELATED APPLICATIONS This application is a continuation-in-part (CIP) of US patent application Ser. No. 14 / 460,511, filed Aug. 15, 2014, which further includes a US application filed Apr. 1, 2014. This is a continuation-in-part application (CIP) of patent application No. 14 / 242,429, which is further a continuation-in-part application (CIP) of US patent application Ser. No. 14 / 138,499, filed Dec. 23, 2013. This is further a continuation-in-part (CIP) of US Patent Application No. 13 / 913,402 filed June 8, 2013, which is further a US Patent Application filed February 6, 2013. 13 / 760,699, a continuation-in-part application (CIP), which is further a continuation-in-part application (CIP) of US patent application 13 / 572,071 filed on August 10, 2012, which February 2011 This is a continuation-in-part (CIP) of US Patent Application No. 13 / 021,730 filed on the 5th, which further includes US Patent Application No. 12 / 793,772 filed on June 4, 2010 (US Patent No. 8 , 736,959), which is a continuation-in-part application (CIP) of US patent application Ser. No. 12 / 388,395 filed Feb. 18, 2009 (US Pat. No. 8,749,881). This is a continuation-in-part (CIP), which is further a continuation-in-part (CIP) of US patent application 11 / 837,529 (US Pat. No. 7,903,339) filed on August 12, 2007 It is. US Patent Application No. 13 / 913,402 filed June 8, 2013 is a continuation-in-part (CIP) of US Patent Application 13 / 014,398 filed January 26, 2011, which is Further, this is a continuation-in-part (CIP) of US patent application Ser. US Patent Application No. 13 / 014,398 filed January 26, 2011 is a portion of US Patent Application No. 13 / 014,398 filed January 13, 2010 (US Pat. No. 8,593,728). This is a continuation application (CIP), which is further a partial continuation application (CIP) of US patent application Ser. No. 12 / 389,256 (US Pat. No. 8,329,247) filed on Feb. 19, 2009. All of these are incorporated by reference in their entirety.

  Pigments made from multilayer structures are known. In addition, pigments that exhibit or result in highly colored omnidirectional structural colors are also known. However, prior art pigments required as many as 39 thin film layers to obtain the desired color characteristics.

  It should be understood that the cost associated with the production of thin film multilayer pigments is proportional to the number of layers required. Therefore, the costs associated with producing a high color omnidirectional structural color using a multilayer stack of dielectric materials can be very expensive. Therefore, high color omnidirectional structural colors that require minimal thin film layers are desirable.

  A multilayer structure that provides a red omnidirectional structural color is provided. The multilayer structure includes a core layer, a semiconductor layer extending across the core layer, and a dielectric layer extending across the semiconductor layer. This semiconductor layer absorbs more than 70% of incident white light having a wavelength less than 550 nanometers (nm). Furthermore, the dielectric layer, when combined with the core layer, reflects more than 70% of the incident white light having a wavelength generally greater than 550 nm. In combination, the core layer, the semiconductor layer, and the dielectric layer are: (1) a narrow band of visible electromagnetic radiation (reflection peak or reflection) having a central wavelength between 550 and 700 nm and a width less than 200 nm. And (2) forming an omnidirectional reflector having a color shift less than 100 nm when the omnidirectional reflector is viewed from an angle between 0-45 °. In some examples, the narrow band width of reflected visible electromagnetic radiation is less than 175 nm, preferably less than 150 nm, more preferably less than 125 nm, and even more preferably less than 100 nm.

  The pigment can be made from the multilayer structure by utilizing a sacrificial layer to produce a coating of the multilayer structure on the membrane. After the sacrificial layer is removed, the stripped coating is crushed into individual pieces with a maximum surface length of 20 μm and a thickness of 0.3-1.5 μm. This piece can then be mixed with a polymer material such as a binder, additive, basecoat resin, etc. to provide an omnidirectional structural color paint.

FIG. 1A is a schematic illustration of an electric field point at or near zero in a ZnS dielectric layer exposed to electromagnetic radiation (EMR) having a wavelength of 500 nm. FIG. 1B shows the square of the absolute value of the electric field (| E | ² ) and the thickness of the ZnS dielectric layer shown in FIG. 1A when exposed to EMR having wavelengths of 300, 400, 500, 600, and 700 nm. It is a graph which shows the relationship. FIG. 2 is a schematic illustration of a dielectric layer extending over a substrate or reflector layer and exposed to electromagnetic radiation at an angle θ relative to the direction perpendicular to the outer surface of the dielectric layer. FIG. 3 is a schematic diagram of a ZnS dielectric layer with a Cr absorber layer located at zero or near zero electric field point in the ZnS dielectric layer with respect to an incident EMR having a wavelength of 434 nm. FIG. 4 shows reflectivity% and reflection for a multilayer laminate without a Cr absorber layer (eg, FIG. 1A) and a multilayer laminate with a Cr absorber layer (eg, FIG. 3A) exposed to white light. It is a graph which shows the relationship with an EMR wavelength. FIG. 5A is a graph showing the first and second harmonics exhibited by a ZnS dielectric layer (eg, FIG. 1A) extending over the Al reflector layer. FIG. 5B shows a multilayer having a ZnS dielectric layer extending over the Al reflector layer and a Cr absorber layer positioned within the ZnS dielectric layer to absorb the second harmonic shown in FIG. 5A. It is a graph which shows the relationship between reflectance% and a reflective EMR wavelength about a laminated body. FIG. 5C shows a multilayer stack having a ZnS dielectric layer extending over the Al reflector layer and a Cr absorber layer positioned within the ZnS dielectric layer to absorb the first harmonic shown in FIG. 5A. It is a graph which shows the relationship between reflectance% and a reflective EMR wavelength about a body. FIG. 6A is a graph showing the relationship between the square of the electric field and the thickness of the dielectric layer indicating the angular dependence of the electric field of the Cr absorber layer when exposed to incident light at 0 ° and 45 °. FIG. 6B shows the% absorbance by the Cr absorber layer and the reflected EMR wavelength when exposed to white light at angles of 0 ° and 45 ° to the normal to the outer surface (0 ° is perpendicular to the surface). It is a graph which shows the relationship. FIG. 7A is a schematic diagram of a red omnidirectional structural color multilayer stack according to an embodiment of the present invention. FIG. 7B shows the relationship between the absorbance% of the Cu absorber layer shown in FIG. 7A and the reflected EMR wavelength when the multilayer stack shown in FIG. 7A is exposed to white light at incident angles of 0 ° and 45 °. It is a graph. FIG. 8 shows a comparison of the calculation / simulation data and experimental data of the relationship between the reflectance% and the reflected EMR wavelength of a red omnidirectional structural color multilayer stack for proof of concept exposed to white light at an incident angle of 0 °. It is a graph to show. FIG. 9 is a schematic diagram of an omnidirectional structural color multilayer stack according to an embodiment of the present invention. FIG. 10 is a schematic diagram of an omnidirectional structural color multilayer stack according to an embodiment of the present invention. FIG. 11 is a schematic diagram of an omnidirectional structural color multilayer stack according to an embodiment of the present invention. FIG. 12 is a schematic diagram of an omnidirectional structural color multilayer stack according to an embodiment of the present invention. FIG. 13 is a scanning electron microscope (SEM) image of a piece or pigment having a multilayer laminate structure according to an embodiment of the present invention. FIG. 14 is an SEM image of a cross section of each small piece shown in FIG. FIG. 15A is a schematic illustration of a panel designed and manufactured according to an embodiment of the present invention and painted with an orange pigment having a hue of 36 ° on the color map shown in FIG. 15D. FIG. 15B is a schematic representation of a panel designed and manufactured according to an embodiment of the present invention and painted with a pigment having a dark red color having a hue of 26 ° on the color map shown in FIG. 15D. FIG. 15C is a schematic illustration of a panel designed and manufactured according to an embodiment of the present invention and painted with a pigment having a bright pink color with a hue of 354 ° on the color map shown in FIG. 15D. FIG. 15D is an a ^* b ^* color map using the CIELAB color space. FIG. 15E is a schematic diagram of an 11-layer design used in paint pigments represented by FIGS. 15A-15C. FIG. 16A is a schematic diagram of a seven-layer stack according to an embodiment of the present invention. FIG. 16B is a schematic diagram of a seven-layer stack according to an embodiment of the present invention. FIG. 16C is a schematic diagram of a seven-layer stack according to an embodiment of the present invention. FIG. 16D is a schematic diagram of a seven-layer stack according to an embodiment of the present invention. FIG. 17 shows a portion of the a * b * color map using the CIELAB color space, comparing the saturation and hue shift between the conventional paint and the paint used to paint the panel shown in FIG. 15B. It is a graph to show. FIG. 18 is a graph showing the relationship between reflectance and wavelength for a seven-layer design product based on an embodiment of the present invention. FIG. 19 is a graph showing the relationship between reflectance and wavelength for a seven-layer design product based on an embodiment of the present invention. FIG. 20 is a schematic diagram of a five-layer stack according to another embodiment of the present invention. FIG. 21 is a graph showing the relationship between the reflectance and the wavelength of a two-layer design product that provides a five-layer laminate according to another embodiment of the present invention. FIG. 22 is a schematic diagram of a seven-layer laminate according to another embodiment of the present invention. FIG. 23 is a graph showing the relationship between reflectance and wavelength of a three-layer design product that provides a seven-layer laminate according to another embodiment of the present invention. FIG. 24 is a schematic diagram of an 11-layer stack according to another embodiment of the present invention. FIG. 25 is a graph showing the relationship between reflectance and wavelength of a 5-layer design product that provides an 11-layer laminate according to another embodiment of the present invention. FIG. 26 is a graph showing the relationship between reflectance and wavelength of a six-layer design product according to another embodiment of the present invention. FIG. 27 is a graph showing the relationship between reflectance and wavelength of a four-layer design product according to another embodiment of the present invention. FIG. 28 is a graph showing the relationship between reflectance and wavelength of a five-layer design product according to another embodiment of the present invention. FIG. 29 is a graph showing the relationship between reflectance and wavelength of a four-layer design product according to another embodiment of the present invention.

  A multilayer stack is provided that provides an omnidirectional structural color, such as a red omnidirectional color. Thus, multilayer laminates have applications as paint applications, thin films that provide the desired color, and the like.

A multilayer stack that provides an omnidirectional structural color includes a core layer, a semiconductor layer extending across the core layer, and a dielectric layer extending across the semiconductor layer. This semiconductor layer absorbs more than 70% of incident white light having a wavelength of less than 550 nm. The dielectric layer, in combination with this core layer, reflects more than 70% of incident white light having a wavelength greater than 550 nm. The thickness of the dielectric layer is such that the wavelength of the incident white light of more than 70% reflected is greater than 550 nm, 560 nm, 580 nm, 600 nm, 620 nm, 640 nm, 660 nm, 680 nm, or intermediate between them It can be considered that the wavelength can be set to be a predetermined wavelength. In other words, on the Lab color system map, the thickness of the dielectric layer so that a specific color having a desired color with saturation and / or lightness between 35 and 350 is reflected and can be observed by the human eye Can be selected and manufactured. Furthermore, for the purposes of this disclosure, the color is defined by tan ⁻¹ (b / a), where a and b are the color coordinates of the Lab color system.

  In some examples, the multilayer stack has a color between 315 ° and 45 ° in the Lab color space. Furthermore, the multilayer stack has a saturation greater than 50 and a color shift of less than 30 °. In other examples, the saturation is greater than 55, preferably greater than 60, more preferably greater than 65, and / or the color shift is less than 25 °, preferably less than 20 °, more preferably Is less than 15 °, even more preferably less than 10 °. In some examples, the core and dielectric layers reflect more than 80% of incident white light having a wavelength greater than 550 nm, and in other examples, more than 90%. Further, in some examples, the semiconductor layer absorbs more than 80% of incident white light having a wavelength less than approximately 550 nm, and in other examples, more than 90%.

  In the text, “approximately” means + and / or −20 nm in some examples, + and / or −30 nm in other examples, + and / or −40 nm in still other examples, and still other examples. Should be understood as referring to + and / or −50 nm.

  The core layer, the semiconductor layer, and the dielectric layer have a central wavelength of 550 nm and reflect a narrow band of electromagnetic radiation (hereinafter referred to as a reflection peak or a reflection band) that is the visible IR edge in the EMR spectrum. Form the body. When the omnidirectional reflector is exposed to white light and observed from an angle between 0 ° and 45 °, the reflection band has a width of less than 200 nm and the color shift is less than 100 nm. The color shift may be in the form of a shift in the center wavelength of the reflection band, or alternatively in the form of a shift in the reflection band at the UV side end. For the purposes of the present invention, the reflection band of electromagnetic radiation is defined as the width of the reflection band at half the reflection height of the maximum reflection wavelength in the visible spectrum. Furthermore, the narrow band of reflected electromagnetic radiation, for example the “color” of the omnidirectional structural color, has a color shift of less than 35 °, and in one embodiment has a color shift of less than 25 °.

The core layer has a thickness of 50-200 nm and may be a reflector core layer, an absorber / reflector core layer, or a dielectric layer. The reflector core layer is made of a reflector material such as aluminum (Al), silver (Ag), platinum (Pt) and / or alloys thereof. The absorber / reflector core layer is made of an absorber / reflector material such as chromium (Cr), copper (Cu), gold (Au), tin (Sn) and / or alloys thereof. The dielectric core layer is made from a dielectric material, such as glass and / or mica, or alternatively from a colored dielectric material, such as Fe ₂ O ₃ , Cu ₂ O and / or combinations thereof. It is a body layer.

  The semiconductor layer has a thickness between 5 and 400 nm and has a semiconductor material, for example, silicon (Si), amorphous Si, germanium (Ge), or an electronic forbidden band in the visible range of the electromagnetic spectrum. Made from other semiconductor layers and combinations thereof. It should be understood that the term Si refers to crystalline Si.

The dielectric layer has a thickness of between 0.1QW and 4.0QW for the desired tuning wavelength and the tuning wavelength determined by the desired target wavelength in visible white light. Dielectric layers made from dielectric materials have a refractive index greater than 1.6, such as ZnS, TiO ₂ , Si ₂ N ₄ , HfO ₂ , Nb ₂ O ₅ , Ta ₂ O ₅ and combinations thereof. doing. In one example, the dielectric layer is a colored dielectric layer made from a colored dielectric material, such as Fe ₂ O ₃ , Cu ₂ O, and combinations thereof.

  In certain embodiments disclosed herein, the omnidirectional reflector includes an optional partial absorber layer that extends between the semiconductor layer and the dielectric layer. The partial absorber layer has a thickness of 2-30 nm and is made from selected materials such as Cr, Cu, Au, Sn and combinations thereof.

  In another embodiment, the omnidirectional reflector has a second semiconductor layer in addition to the aforementioned semiconductor layer (also known as the first semiconductor layer). Furthermore, the second semiconductor layer extends over the dielectric layer, and is disposed on the opposite side of the first semiconductor layer with respect to the dielectric layer. In the presence of the second semiconductor layer, the omnidirectional reflector further extends across the second semiconductor layer in addition to the aforementioned dielectric layer (also known as the first dielectric layer). The second dielectric layer may be disposed on the opposite side of the first dielectric layer with respect to the second semiconductor layer.

  The semiconductor layer is selected to absorb a desired range of wavelengths in the white light spectrum and reflect another desired range of the white light spectrum. For example, it absorbs electromagnetic radiation at wavelengths according to purple, blue, green, yellow (eg 400-500 nm), but reflects electromagnetic radiation according to red (ie 580-infrared (IR) range). As such, semiconductors are designed and produced.

  The overall thickness of the multilayer stack making up the omnidirectional reflector disclosed herein is less than 2 microns (μm), in some instances less than 1.5 μm, and in other examples 1 It is less than 0.0 μm, and in another example, it is less than 0.75 μm.

  In some examples, the dielectric layer has an optical thickness of 0.1 to 2.0 QW, and in other examples, the dielectric layer has a thickness between 0.1 and 1.8 QW. doing. In still other examples, the dielectric layer has an optical thickness of less than 1.9QW, for example, less than 1.8QW, less than 1.7QW, less than 1.6QW, less than 1.5QW, 1.4QW. Less than, less than 1.3QW, less than 1.2QW, or less than 1.1QW. Alternatively, the dielectric layer has an optical thickness greater than 2.0 QW.

The dielectric layer has a refractive index greater than 1.60, 1.62, or 1.70 and is made of a dielectric material such as ZnS, Si ₂ N ₄ , TiO ₂ , HfO ₂ , Nb ₂ O ₅ , Made from Ta ₂ O ₅ , combinations thereof, and others similar to these. In some examples, the dielectric layer is a colored dielectric layer or a selective dielectric layer made from colored dielectric materials, such as Fe ₂ O ₃ , Cu ₂ O, and the like. For the purposes of the present invention, the term “colored dielectric material” or “colored dielectric layer” refers to a dielectric material or dielectric layer that transmits only a portion of the transmitted white light and reflects the other portion of the white light. Is mentioned. For example, the colored dielectric layer can transmit electromagnetic radiation having a wavelength between 400 and 600 nm and reflect wavelengths greater than 600 nm. Thus, the colored dielectric material or colored dielectric layer has an orange, red, and / or orange-red appearance.

  The position of the dielectric layer is such that a zero or near zero energy boundary exists between the absorber or semiconductor layer and the dielectric layer. In other words, the dielectric layer has a thickness such that zero or a near-zero energy boundary is located at the dielectric layer-semiconductor layer or dielectric layer-absorber layer boundary. It should be understood that the thickness of the dielectric layer in the presence of zero or near zero energy field is a function of the incident EMR wavelength. In addition, a wavelength corresponding to an electric field of zero or near zero transmits a dielectric layer-semiconductor layer boundary or a dielectric layer-absorber layer boundary, while a wavelength not corresponding to an electric field of zero or near zero. It should be further understood that does not penetrate these. In this way, the desired incident white light wavelength is transmitted through the dielectric layer-semiconductor layer boundary or dielectric layer-absorber layer boundary, reflected at the core layer, and the dielectric layer-semiconductor layer boundary or The thickness of the dielectric layer is designed and produced to pass back through the dielectric layer-absorber layer boundary. Similarly, the thickness of the dielectric layer is made such that unwanted incident white light wavelengths are not transmitted through the dielectric layer-semiconductor layer boundary or the dielectric layer-absorber layer boundary.

  From the above, wavelengths that do not correspond to zero or near-zero electric field boundaries are absorbed by the semiconductor layer or absorber layer and are therefore not reflected. In this way, the desired “clear” color, also known as the structural color, is provided. In addition, the thickness of the dielectric layer allows the desired first and / or second harmonics to be red on the surface and provide a surface having an omnidirectional appearance. It is the thickness that is made.

  With respect to the dielectric layer for the absorber layer described above and an electric field of zero or near zero, FIG. The ZnS dielectric layer has a total thickness of 143 nm and there is a zero or near zero energy point at 77 nm for incident electromagnetic radiation having a wavelength of 500 nm. In other words, the ZnS dielectric layer exhibits an electric field of zero or near zero at a distance of 77 nm from the Al reflector for incident EMR having a wavelength of 550 nm. In addition, FIG. 1B provides a graph of the energy field across the ZnS dielectric layer for a number of different incident EMR wavelengths. As shown in the graph, the dielectric layer has a zero electric field at a thickness of 77 nm for a wavelength of 500 nm, but for EMR wavelengths of 300, 400, 600, and 700 nm. It has a non-zero electric field at a thickness of 77 nm.

  Without being limited by principle, the calculation of the thickness of the energy point at or near zero of the dielectric layer, for example as illustrated in FIG. 1A, is discussed below.

Referring to FIG. 2, a dielectric layer 4 having a total thickness “D”, incremental thickness “d” and refractive index “n” on a substrate or core layer 2 having a refractive index “n _s ” is shown. ing. Incident light strikes the outer surface 5 of the dielectric layer 4 at an angle θ with respect to a line 6 perpendicular to the outer surface 5 and is reflected from the outer surface 5 at the same angle. Incident light passes through the outer surface 5 into the dielectric layer 4 at an angle θ _F with respect to the line 6 and strikes the substrate layer 2 at an angle θ _s .

  Referring to FIG. 3, Equation 19 shows that the electric field point in the ZnS dielectric layer shown in FIG. 1A when exposed to an EMR having a wavelength of 434 nm is 70 nm (instead of 77 nm for a wavelength of 500 nm). Used to calculate what is in). In addition, a 15 nm thick Cr absorber layer was inserted 70 nm thick from the Al reflector, resulting in a zero or near zero electric field ZnS-Cr boundary. Such a structure of the present invention allows light having a wavelength of 434 nm to pass through the Cr-ZnS boundary, but absorbs light that does not have a wavelength of 434 nm. In other words, the Cr-ZnS boundary has an electric field of zero or near zero for light having a wavelength of 434 nm, and this causes 434 nm light to pass through this boundary. However, the Cr—ZnS boundary does not have an electric field of zero or near zero for light that does not have a wavelength of 434 nm, and thus this light is absorbed by the Cr absorber layer and / or the Cr—ZnS boundary. And is not reflected by the Al reflector layer.

  It should be understood that a few percent of the desired 434 nm ± 10 nm light passes through the Cr-ZnS boundary. However, it should be further understood that such a narrow band of reflected light, for example 434 ± 10 nm, still provides a clear structural color to the human eye.

  This result of the Cr absorber in the multilayer stack in FIG. 3 is illustrated in FIG. 4 where the function of reflectivity and reflected EMR wavelength is shown. As shown by the dotted line corresponding to the ZnS dielectric layer shown in FIG. 3 without the Cr absorber layer, a narrow reflection peak exists at about 400 nm, but a broader peak exists at about 500 nm and above. In addition, there is still a large amount of reflected light in the 500 nm wavelength region. Thus, there are two peaks that inhibit the multilayer stack from having or exhibiting a structural color.

  In contrast, the solid line in FIG. 4 corresponds to the structure shown in FIG. 3 in which a Cr absorber layer is present. As shown in the figure, there is a sharp peak at about 434 nm and a sharp decrease in reflectivity is provided by the Cr absorber layer for wavelengths above 434 nm. It should be understood that a sharp peak represented by a solid line appears visually as a sharp / structural color. Further, FIG. 4 illustrates where the reflection peak or band width is measured, for example, the band width is determined in the portion of the reflectance that is 50% of the maximum of the reflection wavelength, and this portion is further divided by half. Also known as the value range (FWHM).

  For the omnidirectional behavior of the multilayer stack shown in FIG. 3, the thickness of the ZnS dielectric layer is designed or set so that only the first harmonic of the reflected light is provided. It should be understood that this is sufficient for the “blue” color, however, further consideration is necessary to produce the “red” color. For example, angle-independent control for red requires a thicker dielectric layer, which inevitably presents a high harmonic design, ie, the presence of a second and even possible third harmonic. Therefore, it is difficult. Furthermore, the dark red space is very narrow. Therefore, the red multilayer laminate has a high angular variation.

In order to overcome the higher angular variation for red, this application discloses a unique and novel design / structure that provides an angle independent red. For example, FIG. 5A illustrates a dielectric layer that exhibits first and second harmonics for incident white light when the outer surface of the dielectric layer is observed from 0 ° and 45 °. As shown in the graph, the thickness of the dielectric layer provides a low angle dependence (small Δλ _c ), however, such multilayer stacks are blue (first harmonic) and red (second harmonic). And thus not suitable for the desired “red only” color. Therefore, concepts / structures have been developed that use absorber layers to absorb unwanted harmonic sequences. In FIG. 5A, the central wavelength (λ _c ) of the reflection band of a given reflection peak and the position of the scattering or shift (Δλ _c ) of the central wavelength when the sample is observed from angles of 0 ° and 45 °. An example is further illustrated.

Referring now to FIG. 5B, the second harmonic shown in FIG. 5A is absorbed by the Cr absorber layer at a suitable dielectric layer thickness (eg, 72 nm), resulting in a sharp blue color. More importantly, FIG. 5C illustrates that red is obtained by absorbing the first harmonic by the Cr absorber layer at different thicknesses of the dielectric layer (eg, 125 nm). ing. However, FIG. 5C further illustrates that the use of a Cr absorber layer would exceed the desired angular dependence of the multilayer stack, for example greater than the desired Δλ _c . .

Compared to blue, a large shift in red λ _c is the fact that the dark red space is very narrow and the fact that the Cr absorber layer absorbs wavelengths corresponding to non-zero electric fields, ie the electric field is zero or zero. It should be understood that when near, it does not absorb light. Accordingly, FIG. 6A illustrates that different incident angles result in different zero or non-zero points for the light wavelength. Such factors result in the angle-dependent absorption shown in FIG. 6B, ie the difference between the 0 ° and 45 ° absorption curves. Thus, to further improve the multilayer stack design and angle independence, for example, an absorber layer that absorbs blue light is used regardless of whether the electric field is zero or nearly zero.

  In particular, FIG. 7A illustrates a multilayer stack in which a Cu absorber layer extends over a ZnS dielectric layer instead of a Cr absorber layer. The result of using such a “colored” or “selective” absorber layer is shown in FIG. 7B, which is a set of 0 ° and 45 ° absorption lines for the multilayer stack illustrated in FIG. 7A. This represents a “no gap” arrangement. Thus, the comparison of FIG. 6B and FIG. 7B shows that the absorption angle independence is significantly improved when the selective absorber layer is used rather than the non-selective absorber layer.

  Based on the above, a multi-layer laminate for proof-of-concept was designed and manufactured. In addition, the calculation / simulation results for the multi-layer stack for proof-of-concept and the actual experimental data of the test were compared. In particular, and as shown in the graph plot of FIG. 8, a bright red color was produced (wavelengths greater than 700 nm are generally invisible to the human eye) and were obtained from calculations / simulations and actual samples. Very good agreement was obtained with the experimental light data. In other words, the calculation / simulation can simulate and / or simulate the results of a multilayer stack design based on one or more embodiments of the invention and / or known multilayer stacks. Can be used for

  Samples of simulated and / or actually produced multilayer stacks are provided in Table 1 below. As shown in the table, the inventive design disclosed herein includes at least five different layer structures. In addition, this sample was simulated and / or made from a wide range of materials. Samples were obtained that showed high saturation, low color shift, and complete reflection. In addition, the 3 and 5 layer samples have a total thickness of 120-200 nm; the 7 layer sample has a total thickness of 350-600 nm; the 9 layer sample has a total thickness of 440-500 nm. Also, the 11-layer sample had a total thickness of 600-660 nm.

  Referring to the actual arrangement of layers, FIG. 9 illustrates half of the five-layer design by reference numeral 10. The omnidirectional reflector 10 includes a reflector layer 100, a dielectric layer 110 extending over the reflector layer 100, and an absorber layer 120 extending over the dielectric layer 110. It should be understood that another dielectric layer and another absorber layer can be placed on the opposite side of the reflector layer 100 to provide a five layer design.

  Reference numeral 20 in FIG. 10 illustrates half of a seven-layer design, in which another dielectric layer 130 extends across the absorber layer 120 so that the dielectric layer 130 absorbs. The body layer 120 is disposed on the opposite side of the dielectric layer 110.

  FIG. 11 illustrates half of the nine-layer design, in which the second absorber layer 105 is located between the reflector layer 100 and the dielectric layer 110. Finally, FIG. 12 illustrates half of the eleven-layer design, in which another absorber layer 140 extends across the dielectric layer 130 and yet another dielectric layer 150 is formed. It extends over the absorber layer 140.

  A scanning electron microscope (SEM) image of a plurality of pigments having a multilayer structure according to an embodiment of the present invention is shown in FIG. FIG. 14 is a higher magnification SEM image of one of the pigments, showing a multilayer structure. These pigments were used in the manufacture of three different red paints, and these red paints were applied to three panels for testing. FIGS. 15A-15C are schematics of a panel that has been actually painted, because the actual picture of the panel appears gray / black and becomes black and white when printed and copied. On the color map in FIG. 15D, FIG. 15A represents an orange color of 36 °, FIG. 15B represents a dark red color of 26 °, and FIG. 15C represents a color of 354 °. Expresses a bright pink color. Furthermore, the dark red panel represented in FIG. 15B had a brightness L * of 44 and a saturation C * of 67.

  FIG. 15E is a schematic representation of an 11 layer design representative of the pigment used to paint the panels depicted in FIGS. For exemplary thicknesses of the various layers, Table 2 provides the actual thickness of each corresponding multilayer stack / pigment. As shown in the thickness values in Table 2, the total thickness of the 11-layer design is less than 2 microns and can be less than 1 micron.

  It should be understood that 7-layer designs and 7-layer multilayer laminates can be used to produce such pigments. Examples of four seven-layer multilayer stacks are shown in FIGS. FIG. 16A illustrates a seven-layer laminate that (1) reflector layer 100; (2) extends across the reflector layer and is disposed on opposite sides with respect to reflector layer 100. FIG. A pair of dielectric layers 110; (3) a pair of selective absorber layers 120a extending over a pair of dielectric layers 110; (4) a pair of selective absorber layers 120a extending over a pair of selective absorber layers 120a; A dielectric layer 130 is provided.

Of course, the thickness of the dielectric layer 110 and the selective absorber layer 120a is such that the boundary between the selective absorber layer 120a and the dielectric layer 110 and the boundary between the selective absorber layer 120a and the dielectric layer 130 are as follows. With the desired light wavelength in the pink-red-orange region (315 ^o <color <45 ^o and / or 550 nm <λ _c <700 nm) of the color map shown in FIG. 15D, it will now have an electric field of zero or near zero. ing. Thus, the desired red light passes through layers 130-120a-110, is reflected at layer 100, and passes back through layers 110-120a-130. In contrast, light that is not red is absorbed by the selective absorber layer 120a. Furthermore, the selective absorber layer 120A has angle-independent absorption for light other than red as discussed above and shown in FIGS. 7A-7B.

It should be understood that the thickness of the dielectric layer 100 and / or 130 is such that the red light reflection of the multilayer stack is omnidirectional. The omnidirectional reflection is measured or determined by the small Δλ _c of the reflected light. For example, in some examples, Δλ _c is less than 120 nm. In other examples, Δλ _c is less than 100 nm. In still other examples, Δλ _c is less than 80 nm, preferably less than 60 nm, even more preferably less than 50 nm, and even more preferably less than 40 nm.

Omnidirectional reflection can be further measured by low color shift. For example, as shown in FIG. 17, the color shift of a pigment made from a multilayer laminate according to an embodiment of the present invention is 30 ° or less (see Δθ ₁ ), and in some examples, The color 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 exhibit a color shift of 45 ° or greater (see Δθ ₂ ).

  FIG. 16B illustrates a seven-layer stack, which is: (1) selective reflector layer 100a; (2) extends across the selective reflector layer 100a and faces each other on both sides thereof. A pair of disposed dielectric layers 110; (3) a pair of selective absorber layers 120a extending over a pair of dielectric layers 110; (4) a pair of selective absorber layers 120a extending over a pair of selective absorber layers 120a; A dielectric layer 130 is provided.

  FIG. 16C illustrates a seven-layer stack, which is: (1) selective reflector layer 100a; (2) extends across the selective reflector layer 100a and is placed on opposite sides thereof. (3) a pair of selective absorber layers 120 extending across the pair of dielectric layers 110; and (4) a pair of dielectrics extending across the pair of selective absorber layers 120. It has a layer 130.

  FIG. 16D illustrates a seven-layer stack, which is: (1) a selective reflector layer 100; (2) extends across the selective reflector layer 100 and is placed on opposite sides thereof. (3) a pair of selective absorber layers 120 extending across the pair of dielectric layers 110; and (4) a pair of dielectrics extending across the pair of selective absorber layers 120. It has a layer 130.

  Referring to FIG. 18, the reflectance percentage and reflected EMR wavelength for a 7-layer design omnidirectional reflector when exposed to white light from angles of 0 and 45 degrees to the reflector surface. And a plot is shown. As shown in this plot, the 0 ° and 45 ° curves provided by the omni-directional reflector for wavelengths below 550 nm both represent very small reflectivity, eg, less than 10%. However, as shown by this curve, the reflector provides a sharp increase in reflectivity at wavelengths between 560 and 570 nm, reaching a maximum of about 90% at 700 nm. It should be understood that the right hand (IR side) portion or region of the curve graph represents the IR portion of the reflection band provided by the reflector.

The sharp increase in reflectivity provided by this omni-directional reflector is characterized by the UV side edge of each curve extending from a low reflectivity part at wavelengths below 550 nm to a high reflectivity part, eg> 70%. . The straight line portion 200 on the UV end side is inclined at an angle (β) larger than 60 ° with respect to the x-axis, and has a length L of about 40 on the reflectance axis and an inclination of 1.4. In one example, the straight portion is inclined at an angle greater than 70 ° with respect to the x-axis, while in other examples β is greater than 75 °. Furthermore, the reflection band has a visible FWMH of less than 200 nm, in some examples a visible FWMH of less than 150 nm and in other examples a visible FWMH of less than 100 nm. In addition, the center wavelength λ _c of the visible reflection band as shown in FIG. 18 is defined as a wavelength equidistant from the UV side end of the reflection band and the IR end of the IR spectrum of the visible FWHM.

  The term “visible FWHM” is the width of the reflection band between the UV end of this curve and the end of the IR spectral region beyond which the reflection supplied by the omnidirectional reflector is not visible to the human eye. Should be understood as referring to. Thus, the inventive designs and multi-layer laminates disclosed herein use the invisible IR portion of electromagnetic radiation to provide a sharp structural color. In other words, despite the fact that the reflector reflects a wider band of electromagnetic radiation that extends into the IR region, the omnidirectional reflector disclosed herein provides a narrow band of reflected visible light. In order to do so, the invisible IR portion of the electromagnetic radiation spectrum is utilized.

Referring to FIG. 19, a plot of% reflectance vs. wavelength for another 7-layer design omnidirectional reflector when exposed to white light from 0 ° and 45 ° angles to the reflector surface is shown. Has been. In addition, an omnidirectional property definition or characterization provided by the omnidirectional reflector disclosed herein is shown. In particular, also when the reflection band provided by the reflector of the present invention has a maximum, ie the peak shown in the figure, each curve has a central wavelength (λ _c ) defined as the wavelength exhibiting the maximum reflectivity. Yes. The term maximum reflection wavelength can be further used for λ _c .

As shown in FIG. 19, the outer surface of the omnidirectional reflector is 45 ° (λ _c (45 ^o ) compared to the case where the surface is observed at 0 ° ((λ _c (0 ^o )), that is, perpendicular to the surface. )) when observed from, for example, when observed the surface, may look inclined at 45 ° to the human eye, lambda _c shift or substitutions result in. the lambda _c shift ([Delta] [lambda] _c) the total Provides a degree of omnidirectional characteristics of a directional reflector, which is, of course, a perfect omnidirectional reflector when zero shift, i.e. no shift, however, the omnidirectional reflector disclosed herein is a reflective It is visible to the human eye as if the color of the body surface has not changed, and this can provide a Δλ _c of less than 100 nm where the reflector is omnidirectional from a practical standpoint. In an embodiment, the omnidirectional reflector disclosed herein is Can provide [Delta] [lambda] _c of less than 5 nm, providing a [Delta] [lambda] _c of less than 15nm is the [Delta] [lambda] _c of less than 50nm in another embodiment, the [Delta] [lambda] _c of less than 25nm in yet another example, in another embodiment from further Such a shift in Δλ _c can be a plot of the actual reflectivity versus wavelength of the reflector, and / or alternatively modeling the reflector if the material and layer thickness are known. Can be measured.

Another definition or characterization of the omnidirectional characteristics of the reflector can be measured by shifting the sides of a given series of angular reflection bands. For example, from an omnidirectional reflector observed from 0 ° (S _L (0 ^o )) compared to the UV-side edge for reflections from the same reflector observed from 45 ° (S _L (45 ^o )) The UV-side edge shift or substitution (ΔS _L ) with respect to the reflection provides a measure of the omnidirectional characteristics of the omnidirectional reflector. In addition, [Delta] [lambda] _c, for example, [Delta] [lambda] _c, i.e., the reflection band (diagram a peak corresponding to the maximum reflection wavelength not in the visible region of the one to the reflector supplies a reflection band similar among shown in FIG. 18 to use the 18 reference), it is preferable to use a [Delta] S _L as the degree of omnidirectional reflectivity. It should be understood that the (ΔS _L ) shift of the UV side edge can be measured and / or done in the visible FWHM.

Of course, the zero shift, ie no shift at all (ΔS _L = 0 nm), characterizes a perfect omnidirectional reflector. However, the omnidirectional reflector disclosed herein appears to the human eye as if the color of the reflector's surface does not change, so from a practical standpoint, the reflector is omnidirectional. , ΔS _L of less than 100 nm can be provided. In some examples, the omnidirectional reflectors disclosed herein can provide ΔS _L of less than 75 nm, in other examples, can provide ΔS _L of less than 50 nm, and in other examples ΔS _L of less than 25 nm can be provided, and in yet other examples, ΔS _L of less than 15 nm can be provided. Such ΔS _L shifts can be measured by plotting the actual reflectivity versus wavelength of the reflector and / or alternatively by modeling the reflector if the material and layer thickness are known. .

Referring to FIG. 20, a five-layer design product according to another embodiment is schematically indicated at reference numeral 30. The five-layer stack includes a core layer 300, a pair of semiconductor layers 310 extending across the core layer 300 and facing both sides thereof, and a pair of semiconductor layers 310 extending across the outer surfaces of the pair of semiconductor layers 310. A dielectric layer 320 is provided. The core layer has a thickness of 50-200 nm and may be a reflector core layer, an absorber / reflector core layer, or a dielectric core layer. The reflector core layer is made of a reflector material such as Al, Ag, Pt, alloys thereof, and the like. The absorber / reflector core layer is made of an absorber / reflector material such as Cr, Cu, Au, Sn, alloys thereof, and the like. The dielectric core layer is made from a dielectric center material such as glass, mica and the like. Alternatively, the dielectric center material may be a colored dielectric material, such as Fe ₂ O ₃ , Cu ₂ O and the like.

The semiconductor layer 310 has a thickness of 5 to 400 nm and has any semiconductor material, such as Si, amorphous Si, Ge, these having an electronic forbidden band in the visible range of the electromagnetic spectrum. Made from combinations and other similar types. In addition, the dielectric layer 320 has a thickness of 0.1QW to 4.0QW and has any refractive material known to those skilled in the art having a refractive index greater than 1.6, such as ZnS, _{TiO 2, Si 2 N 4,} HfO 2, Nb 2 O 5, Ta 2 O 5, is also made from those combinations thereof, and the like.

The reflection spectrum of such a five-layer stack is shown in FIG. 21, where a pair of amorphous Si semiconductor layers 310 and a pair of Si ₃ N ₄ dielectric layers 320 are on the core layer 300. The percent reflection (% R) versus wavelength is shown. As shown in the figure, this multilayer stack reflects 70% of incident electromagnetic radiation having a wavelength of approximately 640 nm and absorbs more than 70% of incident electromagnetic radiation having a wavelength of less than approximately 550 nm. Further, although not shown in the figure, a reflection spectrum at an observation angle of 0 °, that is, an observation angle perpendicular to the surface is shown, and the peak of the reflection band is shifted by less than 45 nm when observed from 45 °.

  Referring to FIG. 22, a seven-layer design according to another embodiment is shown generally at reference numeral 32. The multilayer stack 32 is similar to the multilayer stack 30 shown in FIG. 20, however, there is an optional partial absorber layer 315 between the semiconductor layer 310 and the dielectric layer 320. This partial absorber layer has a thickness of 2 to 30 nm and is made from partial absorber materials such as Cr, Cu, Au, Sn, alloys thereof, and the like.

The reflection spectrum of such a seven-layer stack having a core layer 300, a pair of amorphous Si semiconductor layers 310, a pair of Cr partial absorber layers 315, and a pair of Si ₃ N ₄ dielectric layers 320 is shown in FIG. Has been. As shown in the figure, this multilayer stack reflects more than 70% of incident electromagnetic radiation having a wavelength of approximately 640 nm and absorbs more than 70% of incident electromagnetic radiation having a wavelength of less than approximately 550 nm. Further, although not shown in the figure, a reflection spectrum is shown at an observation angle of 0 °, ie, an observation angle perpendicular to the surface, and the peak of the reflection band shifts less than 45 nm when observed from 45 °.

  An eleven-layer design according to another embodiment is indicated by reference numeral 34 in FIG. In particular, except that a pair of second semiconductor layers 330 extending across the first dielectric layer 320 and a pair of dielectric layers 340 extending across the pair of second semiconductor layers 330 are added, This 11-layer design is similar to the 7-layer design 32 shown in FIG. The eleven-layer design 34 includes an optional partial absorber layer 315, however, it should be understood that this is not required.

The core layer 300, the pair of first amorphous Si semiconductor layers 310, the pair of Cr partial absorber layers 315, the pair of first Si ₃ N ₄ dielectric layers 320, the pair of second Si semiconductor layers 330, and the pair of The reflection spectrum of such an 11-layer stack having a second Si ₃ N ₄ dielectric layer 320 is shown in FIG. As shown in the figure, this multilayer stack reflects 70% of incident electromagnetic radiation having a wavelength greater than approximately 550 nm and absorbs more than 70% of incident electromagnetic radiation having a wavelength less than approximately 550 nm. Further, although not shown in the figure, a reflection spectrum is shown at an observation angle of 0 °, ie, an observation angle perpendicular to the surface, and the peak of the reflection band shifts less than 45 nm when observed from 45 °.

26 shows a core layer 300, a pair of first amorphous Si semiconductor layers 310, a pair of first Si ₃ N ₄ dielectric layers 320, a pair of second Si semiconductor layers 330, and a pair of second Si _3. N ₄ dielectric layer 340, a pair of second Si ₃ N ₄ dielectric layer 340 extending over the surface, a pair of third Si semiconductor layers extending over the surface, and a pair of third Si semiconductor layers extending over the outer surface The reflection spectrum of a 13-layer stack having a pair of existing third Si ₃ N ₄ dielectric layers is shown. As shown in the figure, this multilayer stack reflects more than 70% of incident electromagnetic radiation having a wavelength greater than approximately 550 nm and absorbs more than 70% of incident electromagnetic radiation having a wavelength less than approximately 550 nm. Further, although not shown in the figure, a reflection spectrum is shown at an observation angle of 0 °, ie, an observation angle perpendicular to the surface, and the peak of the reflection band shifts less than 45 nm when observed from 45 °.

27 denotes a core layer 300, a pair of first amorphous Si semiconductor layers 310, a pair of first Si ₃ N ₄ dielectric layers 320, a pair of second Si semiconductor layers 330, and a pair of second Si ₃ N _4. The reflection spectrum of a nine-layer design product with a dielectric layer 340 is shown. As shown in the figure, this multi-layer stack utilizes the electromagnetic radiation spectrum in the invisible IR region to reflect more than 70% of incident electromagnetic radiation having a wavelength greater than approximately 550 nm, and for incident electromagnetic radiation having a wavelength less than approximately 550 nm. Absorbs more than 70% of the radiation. Further, although not shown in the figure, a reflection spectrum is shown at an observation angle of 0 °, ie, an observation angle perpendicular to the surface, and the peak of the reflection band shifts less than 45 nm when observed from 45 °.

FIG. 28 illustrates a core layer, a pair of first Si ₃ N ₄ dielectric layers extending across the core layer, and a pair of first Si semiconductor layers extending across the pair of first Si ₃ N ₄ dielectric layers. , second Si ₃ N ₄ dielectric layer of a pair extending over the pair of first Si semiconductor layer, the second Si semiconductor layer of a pair extending over a pair second Si ₃ N ₄ dielectric layer , And the reflection spectrum of an 11-layer design with a pair of third Si ₃ N ₄ dielectric layers extending across the pair of second Si semiconductor layers. As shown in the figure, the multilayer stack utilizes more than 70% of incident electromagnetic radiation having a wavelength greater than approximately 550 nm, utilizing incident electromagnetic radiation spectrum in the invisible IR region, and incident electromagnetic radiation having a wavelength less than approximately 550 nm. Absorbs more than 70%. Further, although not shown in the figure, a reflection spectrum is shown at an observation angle of 0 °, ie, an observation angle perpendicular to the surface, and the peak of the reflection band shifts less than 45 nm when observed from 45 °. FIG. 29 shows a Cr absorber / reflector 300, a pair of first amorphous Si semiconductor layers 310, a pair of first TiO ₂ dielectric layers 320, a pair of second amorphous Si semiconductor layers 330, and a pair of first The reflection spectrum of a 9 layer design with 2 TiO ₂ dielectric layers 340 is shown. Multilayer stacks do not reflect more than 70% of incident electromagnetic radiation having a wavelength greater than approximately 550 nm, but the design utilizes the invisible IR region to provide greater than 70% of incident electromagnetic radiation at a wavelength less than approximately 550 nm. It represents absorbing. Furthermore, the figure shows how embodiments of the present invention can have a UV side edge shift measured with a visible FWHM of less than 40 nm, such as less than 30 nm.

  The method of manufacturing a multilayer laminate disclosed herein can be any method or process known to those skilled in the art, or one or more methods not yet known to the patentee. . Common known methods include sol-gel methods, layer-by-layer methods, and wet methods such as spin coating. Other known dry methods include sputtering, chemical vapor deposition, and physical vapor deposition such as beam evaporation.

  The multilayer laminate disclosed in the present specification can be used for almost all colored paints such as pigments for paints and thin films applied to surfaces. For example, the pigment can be produced by placing the desired multilayer body on a film having a sacrificial layer. Upon removal of the sacrificial layer, the peeled coating is broken into individual pieces having a maximum surface length of 20 μm and a thickness of 0.3-1.5 μm. This piece is then mixed with a polymer agent, such as a binder, an additive, and a resin coated substrate to provide an omnidirectional structural color paint.

  The above examples and embodiments are for illustrative purposes only, and variations and modifications thereof should be apparent to those skilled in the art and still fall within the scope of the invention. Accordingly, the scope of the present invention extends to the claims and all equivalents thereof.

The present invention further includes the following embodiments:
1. A core layer, a semiconductor layer extending over the core layer, the semiconductor layer absorbing more than 70% of incident white light having a wavelength of less than 550 nm, a dielectric layer extending over the semiconductor layer, the dielectric layer, and A core layer that reflects more than 70% of incident white light having a wavelength greater than 550 nm; the core layer, the semiconductor layer, and the dielectric layer form an omnidirectional reflector, the omnidirectional reflector being Reflects a narrow band of visible electromagnetic radiation having a central wavelength of 550 to 700 nm and a width of less than 200 nm, and the color shift is less than 100 nm when the omnidirectional reflector is observed from an angle between 0 ° and 45 ° A multilayer laminate exhibiting a red omnidirectional structural color.
2. The multilayer stack according to claim 1, wherein the semiconductor layer has a thickness of between 5 and 400 nm.
3. The semiconductor layer is made of a semiconductor material selected from the group comprising Si, amorphous Si, Ge, and / or other semiconductor layers having an electronic forbidden band in the visible range of electromagnetic waves, or these The multilayer laminate according to 2 above, which is a combination of the above.
4). 4. The multilayer laminate according to 3, wherein the dielectric layer has a thickness between 0.1QW and 4.0QW.
5). The dielectric layer has a refractive index greater than 1.6 and is selected from the group consisting of ZnS, TiO ₂ , Si ₂ N ₄ , HfO ₂ , Nb ₂ O ₅ , Ta ₂ O ₅ and combinations thereof. 5. The multilayer laminate as described in 4 above, which is made from a dielectric material.
6). 5. The multilayer laminate according to 4, wherein the dielectric layer is a colored dielectric made from a colored dielectric material selected from the group consisting of Fe ₂ O ₃ , Cu ₂ O, and combinations thereof.
7). 7. The multilayer laminate according to 6, further comprising a partial absorption layer extending between the semiconductor layer and the dielectric layer.
8). The multilayer laminate according to 7, wherein the partial absorber layer has a thickness between 2 and 30 nm.
9. The multilayer laminate according to claim 8, wherein the partial absorber layer is made of a partial absorber material selected from the group consisting of Cr, Cu, Au, Sn, and alloys thereof.
10. In addition to the semiconductor layer, a second semiconductor layer is provided, the second semiconductor layer extends over the dielectric layer, and is disposed on the opposite side of the semiconductor layer with respect to the dielectric layer. The multilayer laminate according to 4, wherein the core layer, the semiconductor layer, the dielectric layer, and the second semiconductor layer form the omnidirectional reflector.
11. 11. The multilayer stack according to 10, wherein the second semiconductor layer has a thickness in the range of 5 to 400 nm.
12 The second semiconductor layer is a semiconductor layer made of a semiconductor material selected from the group consisting of Si, amorphous Si, and Ge, or another semiconductor layer having an electronic forbidden band in the visible region of electromagnetic waves, or these 12. The multilayer laminate according to 11 above, which is a combination.
13. 11. The multilayer laminate according to 10, further comprising a partial absorber layer extending between the semiconductor layer and the dielectric layer.
14 14. The multilayer laminate according to 13, wherein the partial absorber layer has a thickness between 2 and 30 nm.
15. 15. The multilayer laminate according to 14, wherein the partial absorber layer is made of a partial absorber material selected from the group consisting of Cr, Cu, Au, Sn, and alloys thereof.
16. A second dielectric layer in addition to the dielectric layer, the second dielectric layer extending over the second semiconductor layer, and the dielectric with respect to the second semiconductor layer; The core layer, the semiconductor layer, the dielectric layer, the second semiconductor layer, and the second dielectric layer form the omnidirectional reflector; A multilayer laminate as described in 1.
17. 17. The multilayer stack according to 16, wherein the second dielectric layer has a thickness between 0.1QW and 4.0QW.
18. The second dielectric layer has a refractive index of more than 1.6 and is composed of ZnS, TiO ₂ , Si ₂ N ₄ , HfO ₂ , Nb ₂ O ₅ , Ta ₂ O ₅ and combinations thereof. 18. A multilayer stack according to claim 17 made from a selected dielectric material.
19. 18. The multilayer as described in 17 above, wherein the second dielectric layer is a colored dielectric layer made of a colored dielectric material selected from the group consisting of Fe ₂ O ₃ , Cu ₂ O and combinations thereof. Laminated body.
20. 17. The multilayer laminate according to 16, further comprising a partial absorption layer extending between the semiconductor layer and the dielectric layer.
21. 21. The multilayer laminate according to 20, wherein the partial absorber layer has a thickness between 2 and 30 nm.
22. 22. The multilayer laminate according to 21 above, wherein the partial absorber layer is made of a partial absorber material selected from the group consisting of Cr, Cu, Au, Sn, and alloys thereof.
23. 2. The multilayer laminate according to 1, wherein the core layer is selected from the group consisting of a reflector core layer, an absorber / reflector layer, and a dielectric layer.
24. 24. The multilayer laminate according to 23, wherein the core layer is the reflector core layer and has a thickness between 50 and 200 nm.
25. The multilayer laminate according to 24, wherein the reflective core layer is made of a reflector material selected from the group consisting of Al, Ag, Pt, and alloys thereof.
26. 24. The multilayer laminate according to 23, wherein the core layer is the absorber / reflector layer and has a thickness between 50 and 200 nm.
27. 27. The multilayer laminate according to 26, wherein the absorber / reflector core layer is made of an absorber / reflector material selected from the group consisting of Cr, Cu, Au, Sn, and alloys thereof.
28. 24. The multilayer laminate according to 23, wherein the core layer is the dielectric core layer and has a thickness between 50 and 200 nm.
29. 29. The multilayer stack of claim 28, wherein the dielectric core layer is made from a dielectric material selected from the group consisting of glass and mica.
30. 29. The multilayer laminate according to 28, wherein the dielectric core layer is made of a colored dielectric material selected from the group consisting of Fe ₂ O ₃ , Cu ₂ O, and combinations thereof.

Claims (20)

Core layer,
A semiconductor layer extending over the core layer and absorbing more than 70% of incident white light having a wavelength of less than 550 nm;
A dielectric layer extending over the semiconductor layer, wherein the dielectric layer and the core layer reflect more than 70% of incident white light having a wavelength greater than 550 nm;
And the core layer, the semiconductor layer, and the dielectric layer form an omnidirectional reflector, the omnidirectional reflector having a central wavelength of 550 to 700 nm and a width of less than 200 nm of visible electromagnetic radiation. A multilayer laminate that reflects a narrow band and exhibits a red omnidirectional structural color with a color shift of less than 100 nm when the omnidirectional reflector is observed from an angle between 0 ° and 45 °.   The multilayer stack according to claim 1, wherein the semiconductor layer has a thickness of between 5 and 400 nm.   The semiconductor layer is made of a semiconductor material selected from the group consisting of Si, amorphous Si, and Ge, and / or another semiconductor layer having an electronic forbidden band in the visible range of electromagnetic waves, or these The multilayer laminate according to claim 2, which is a combination of   The multilayer stack of claim 3, wherein the dielectric layer has a thickness between 0.1 QW and 4.0 QW. The dielectric layer has a refractive index greater than 1.6 and is selected from the group consisting of ZnS, TiO ₂ , Si ₂ N ₄ , HfO ₂ , Nb ₂ O ₅ , Ta ₂ O ₅ and combinations thereof. 5. A multilayer stack according to claim 4, made from a dielectric material. The multilayer laminate according to claim 4, wherein the dielectric layer is a colored dielectric made of a colored dielectric material selected from the group consisting of Fe ₂ O ₃ , Cu ₂ O, and combinations thereof.   The multilayer laminate according to claim 6, further comprising a partial absorption layer extending between the semiconductor layer and the dielectric layer.   The multilayer laminate according to claim 7, wherein the partial absorber layer has a thickness of between 2 and 30 nm.   The multilayer laminate according to claim 8, wherein the partial absorber layer is made of a partial absorber material selected from the group consisting of Cr, Cu, Au, Sn, and alloys thereof. In addition to the semiconductor layer, it has a second semiconductor layer, the second semiconductor layer extends over the dielectric layer, and is disposed on the opposite side of the semiconductor layer with respect to the dielectric layer ;
The core layer, the semiconductor layer, the dielectric layer, and the second semiconductor layer form the omnidirectional reflector;
The multilayer laminate according to claim 9.   The multilayer stack according to claim 10, wherein the second semiconductor layer has a thickness in the range of 5 to 400 nm.   The second semiconductor layer is a semiconductor layer made of a semiconductor material selected from the group consisting of Si, amorphous Si, and Ge, another semiconductor layer having an electronic forbidden band in the visible region of electromagnetic waves, or these The multilayer laminate according to claim 11, which is a combination.   The multilayer stack according to claim 12, further comprising a partial absorber layer extending between the semiconductor layer and the dielectric layer.   14. A multilayer stack according to claim 13, wherein the partial absorber layer has a thickness between 2 and 30 nm.   The multilayer laminate according to claim 14, wherein the partial absorber layer is made of a partial absorber material selected from the group consisting of Cr, Cu, Au, Sn and alloys thereof. A second dielectric layer in addition to the dielectric layer, the second dielectric layer extending over the second semiconductor layer, and the dielectric with respect to the second semiconductor layer; Located on the opposite side of the body layer;
The core layer, the semiconductor layer, the dielectric layer, the second semiconductor layer, and the second dielectric layer form the omnidirectional reflector;
The multilayer laminate according to claim 15.   The multilayer stack of claim 16, wherein the second dielectric layer has a thickness between 0.1 QW and 4.0 QW. The second dielectric layer has a refractive index of more than 1.6 and is composed of ZnS, TiO ₂ , Si ₂ N ₄ , HfO ₂ , Nb ₂ O ₅ , Ta ₂ O ₅ and combinations thereof. 18. A multilayer laminate according to claim 17, made from a selected dielectric material. Said second dielectric layer is a Fe 2 O _{3, Cu} 2 _O and colored dielectric layer made from a colored dielectric material selected from the group consisting of, according to claim 17 Multilayer laminate.   The multilayer stack of claim 17, further comprising a partial absorption layer extending between the semiconductor layer and the dielectric layer and having a thickness between 20 and 30 nm.