Silicon-based optical coatings for infrared monitoring systems

Abstract

A transmissive assembly includes a front substrate defining a first surface and a second surface, and a transparent coating stack comprising one or more silicon-based layers, wherein the one or more silicon-based layers have a high index of refraction and a low absorption of near infrared light.

Description

AUTO 05269T GEN010 FP1448AWOSILICON-BASED OPTICAL COATINGS FOR INFRARED MONITORING SYSTEMS CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims priority to and the benefit under 35 U.S.C. §119(e) of U.S.Provisional Patent Application No. 63 / 761,847, filed on February 21, 2025, entitled "SILICON BASED OPTICAL COATINGS FOR INFRARED MONITORING SYSTEMS", the entire disclosure of which is hereby incorporated herein by reference.FIELD OF THE DISCLOSURE

[0002] The present disclosure generally relates to silicon-based optical coatings, and more particularlyto silicon-based optical coatings with a high index of refractionand lowabsorption nearinfrared (NIR) wavelengths for a visible reflectance mirrorwith a high NIR transmittance for NIR monitoring.SUMMARY OF THE DISCLOSURE

[0003] According to one aspect of the present disclosure, a transmissive assembly includes a front substrate defining a first surface and a second surface, and a transparent coating stack comprising one or more silicon-based layers, wherein the one or more silicon-based layers have a high index of refraction and a low absorption of near infrared light.

[0004] According to another aspect of the present disclosure, an electro-optic device, includes a front substrate defining a first surface and a second surface, the second surface comprises a first electrically conductive layer, a rear substrate defining a third surface and a fourth surface, the third surface comprises a second electrically conductive layer, an electro optic medium disposed between the second surface and the third surface, and a series of clear mirror stacks comprising a silicon-based material.

[0005] According to another aspect of the present disclosure, a transparent coating stack includes a first layer of a silicon-based material, a layer of silicon dioxide, and a second layer of a silicone-base material, each of the first and second silicon-based layers comprise one of hydrogenated or polycrystalline silicon, the first and second layers silicon-based layers have a high index of refraction and a low absorption of light in approximately 800-1000 nm, the transparent coati ng stack is disposed onto a su bstrate, at least one of the silicon-based layers is between 15 nm and 35 nm thick.

[0006] These and other features, advantages, and objects of the present disclosure will be further understood and appreciated by those skilled in the art by reference to the following specification, claims, and appended drawings.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] In the drawings:

[0008] FIG. 1 is a cross-sectional schematic view of an electro-optic element according to aspects of the present disclosure; and

[0009] FIG. 2 is a graph of the extinction coefficient of Si at 940 nm.DETAILED DESCRIPTION

[0010] The present illustrated embodiments reside primarily in combinations of method steps and apparatus components related to silicon-based materials for an optical coating as components for an infrared monitoring system. Accordingly, the apparatus componentsand method steps have been represented, where appropriate, by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present disclosure so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein. Further, like numerals in the description and drawings represent like elements.

[0011] For purposes of description herein, the terms "upper," "lower," "right," "left," "rear," "front," "vertical," "horizontal," and derivatives thereof, shall relate to the disclosure as oriented in FIG. 1. Unless stated otherwise, the term "front" shall refer to a surface of the device closest to an intended viewer, and the term "rear" shall refer to a surface of the device furthest from the intended viewer. However, it is to be understood that the disclosure may assume various alternative orientations, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings and described in the followingspecification are simply exemplaryembodimentsof the inventive concepts defined in the appended claims. Hence, specific dimensions a nd other physical characteristics relatingto the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise.

[0012] The terms "including," "comprises," "comprising," or any other variation thereof, are intended to covera non-exclusive inclusion, such thata process, method, article, orapparatus that comprises a list of elements does not include onlythose elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element preceded by "comprises a . . . " does not, without more constraints, preclude theexistence of additional identical elements in the process, method, article, or apparatus that comprises the element.

[0013] Aspects of the present disclosure relateto a transparent coating stack may comprise one or more silicon-based layers. These layers collectively may have a high index of refraction and a low to negligible absorption in near infrared light. The silicon-based layers may comprise polycrystalline silicon. Alternatively, the silicon-based layers may comprise hydrogenated amorphous silicon layers. Alternatively, the silicon-based layers may comprise an intermediate level of crystallinity and / or hydrogenation. Additionally, or alternatively, more layers of other materials may be included depending on various practical considerations, which may include but are not limited to cost of the materials, stress, target index of refraction, optical stack design, and sputter rates. Near infrared light is typically considered electromagnetic radiation with wavelengths ranging from approximately 800-2500 nm, or from approximately 800-1000 nm. In some embodiments of the current disclosure, the wavelength of approximately 940 nm maybe used forautomotive applications inside a cabin. The transmitted and reflected color and brightness values reported herein (Y, a*, b*) are derived from the CIE-1964 standard utilizing the D65 illuminant.

[0014] Referring to FIG. 1, reference numeral 10 generally designates an electro-optic element includingan electro-optic medium 14. The transparent coatingstack of the present disclosure may be used in the electro-optic elements 10, which include, but are not limited to, electrochromic devices or a prism-type construction incorporating such electro-optic elements 10. By way of introduction, electrochromic devices generally include an electrooptic medium 14, which may be an electrochromic medium. The electro-optic medium 14 transitions between an inactivated state in which the electro -optic medium 14 is relatively transparent to light having a wavelength within a predetermined wavelength range and an activated state in which the electro-optic medium 14 has a decreased transmission to light within a predetermined wavelength range when an electrical potential is applied to the electro-opticdevice. Theelectro-optic medium 14isdisposed between an anodiccomponent and a cathodic component, which may also be referred to as electroactive components, at least one of which is also electro-optic. The anodic and cathodic components may, alternatively, be referred to as chromophores, electrochromic moieties, molecules or dyes, or electrochromic polymers. The electro-optic and / or electroactive component can providethe electro-optic device with a perceived color when the electro-optic device is in the activated state and / or as the device transitions between the inactivated and activated states.

[0015] Electro-optic components, as described herein, include materials whose color or opacity is affected by an electrical current, such that when an electrical field is applied to the material, the color or opacity changes from a first state to a second state (e.g., the inactivated and activated states). Thus, an electro -opticdevice can exhibit a change in transparencyasa result of electrochemical oxidation and reduction reactionsthat occur between electroactive components (e.g., the anodic components and the cathodic components), in which at least one of the electroactive components is also electro-optic. In other words, when a sufficient electrical potential difference is applied across electrodes of an electro-optic device, the electro-optic medium can shift from a substantially clear state (e.g., a high transmission state, such as the inactivated state) to a substantially dark or darkened state (e.g., a low transmission state, such as the activated state), as well as intermediate states thereto.

[0016] Still referring to FIG. 1, the electro-optic element 10 may include the electro-optic medium 14. The electro-optic element 10 can include a front substrate 18 having a first surface 22 and a second surface 26. A first electrically conductive layer 42 is disposed on the second surface 26. A rear substrate 30 is provided opposite the front substrate 18 and includes a third surface 34 and a fourth surface 38. A second electrically conductive layer 46 is disposed on the third surface 34. The front substrate 18 and the rear substrate 30, along with a sealing member 50 define a chamber 54 for containing the electro-optic medium 14 therein. The front substrate 18 and the rear substrate 30 may be substantially parallel. The first surface 22 and the third surface 34 may be oriented toward a front direction of the electro-optical element 10. The second surface 26 and the fourth surface 38 maybe oriented towards a rear direction of the electro-optical element 10. A direction of view 56 of the electro-optical element 10 may be from the front direction to the rear direction. A transparent coating stack may be disposed on the front substrate 18 orthe rear su bstrate 30. In some examples, the transparent coating stack may be on the second, third, or fourth surface 26, 34, 38.

[0017] The electro-opticelement 10 allowsthe electro-optic device to be operable between a first state of the electro-opticelement 10, which allows electromagnetic radiation havinga wavelength within a predetermined wavelength range to pass through, and a second state, in which a portion, or no electromagnetic radiation having a wavelength within apredetermined wavelength range, is transmitted through the electro -opticelement 10 (e.g., the electro-optic element 10 becomes generally darkened or generally opaque or partially opaque to electromagnetic radiation having a wavelength within the predetermined wavelength range). The second state of the electro-opticelement 10 can be defined relative to the transmissivity of the first state. According to an aspect of the present disclosure, the transmissivity of electromagnetic radiation of a predetermined wavelength or wavelength range through the electro-opticelement 10 in the first state may be greater than about 10%, greaterthan about 12%, greaterthan about 25%, greaterthan about 50%, greaterthan about 55%, or greater than about 85%. Typically, the percentage of reflectance, transmittance, and absorbance of the electro-opticelement 10 sum to 100%. In some aspects, the transmissivity of electromagnetic radiation of the predetermined wavelength or wavelength range through the electro-opticelement 10 in the second state may be lessthan about 20%, less than about 10%, less than about 1%, less than about 0.1%, less than about 0.01%, or less than about 0.001%.

[0018] Thefront and / or rear substrates 18, 30 can be made of glass, plastic, or other optically transparent or translucent material(s), non-limiting examples of which include borosilicate glass, soda lime glass, or polymeric materials, such as natural and synthetic polymeric resins, plastics, and / or composites. Non-limiting examples of such include polyesters (e.g., PET), polyimides (PI), polycarbonates, polysulfones, polyethylene naphtha late (PEN), ethylene vinyl acetate (EVA), acrylate polymers, as well as cyclic olefin copolymers (COC) and cyclic olefin polymers (COP) (such as those commercially available from TOPAS® Advanced Polymers). In some aspects, both the front and rear substrates 18, 30 are made of an optically transparent or translucent material, while, in other aspects, only a single substrate, such as the front substrate 18, is made of an optically transparent ortranslucent material. The front and rear substrates 18, 30 can be made from the same or different materialsand may have the same or different dimensions.

[0019] Alternatively, the electro-optic element 10 may be present in a prism-type construction. The prism-type construction may include a single substrate with a first surface and a second surface; the first and second surfaces may or may not be parallel. In one example, the single substrate hasa varying thickness from topto bottom. Further, the single substrate may be made of glass or plasticweb such as PET. In anotherexample, at least two substrates may be present in the prism-type construction, which may include a forward anda back substrate. The back substrate has a third and a fourth surface. The forward and back substrates may be made of the same material or different materials. In some embodiments, an optically clearadhesive may be used to bond the second surface of the forward substrate with the third surface of the back substrate. Alternatively, the second surface of the front substrate may be laminated usingan optically clearadhesiveto the third surface of the back substrate. In some embodiments, the back substrate may define a concave surface. In other embodiments, both the front and the back substrate are flat.

[0020] According to aspects of the present disclosure, the electro-optic element 10 may have a transflective coating which may be disposed on the second, third, or fourth surface 26, 34, 38. Alternatively, in prism-type constructions, the transflective coating may be disposed on the second surface. The visible reflectance and transmittance of the transflective coating may vary depending on design considerations of the electro-optic element 10. The transflective coating may be the transparent coating stack of the present disclosure. The transparent coating stack may exist in the form of a film. While amorphous silicon as used in the transparent coating stack may have a high refraction index, it may not be ideal as amorphous silicon may have a non-negligible absorption in the visible and the near infrared spectrum. However, amorphous silicon may be useful as it is possible to deposit layers as a part of the transparent coating stack with standard sputtering methods to form a film. Alternatively, crystalline silicon hasa high index of refraction and negligible absorption in the near infrared spectrum, but is unable to be deposited as a film. To achieve a film applied via sputtering method with a high index of refraction and negligible absorption in the near infrared spectrum it may be useful to modifyan amorphous silicon layerto increase the content of crystalline silicon in the amorphous layer. An increase of crystalline silicon from an amorphous silicon layer may be considered as polycrystalline silicon or nanocrystalline silicon.

[0021] According to aspects of the present disclosure, a method of achieving a polycrystalline silicon layer as layers within the transparent coating stack may include depositing silicon material at a high temperature during deposition. Polycrystalline, as used herein, may refer to materials with many crystallites of varying size and orientation within the material, which may exist as a crystal on a small or microscopic scale. In other words, the structure of polycrystalline materials may exist between a spectrum of crystalline materials, with a single crystal with atoms in a near-perfect periodic arrangement, and amorphous materials, with atoms with no periodic arrangement. Alternatively, a method of achieving a polycrystallinesilicon layer may include exposingan amorphous silicon film layer to high temperature by annealing post deposition. The annealing process for silicon may be above 300°C and may vary for different combinations of time and temperature. Either of the above methods may result in the formation of microscopic silicon crystals, resulting in a high index of refraction and reduced absorption in the near infrared spectrum. The resulting silicon-based film may alternatively include an intermediate level of crystallinity. A low absorption may correspond to a high transmittance value of a material. Transmittance maybe measured as a percentage, with 0% transmittance relatingto complete absorption and 100% transmittance relatingto no absorption. In some instances, a material with lowabsorption would have a transmittance value greater than about 60%, greater than about 70%, greater than about 85%, or up to 100%.

[0022] According to another aspect of the disclosure, the silicon-based layers may instead comprise hydrogenated amorphoussilicon layersas opposed to polycrystalline silicon which may achieve the same or similar optical effects. The resulting silicon-based film may alternatively include an intermediate level of hydrogenation. Referring to FIG. 2, this graph shows the relationship between the increase of hydrogen duringthe sputtering process and absorption. During the sputtering process, hydrogen (H2) is introduced as a reactive gas, measured in units of standard cubic centimeters (seem). Argon gas is the primary sputtering gas, which controls the pressure during the process. The graph of FIG. 2 showsan extinction coefficient (k) at 940 nm as being dependent on the hydrogen gas flow. The extinction coefficient is directly linked to absorption. With the increase in the introduction of hydrogen to the process, the amorphous silicon becomes virtually transparent at 940 nm, as evident by k being close to 0.

[0023] The polycrystalline silicon layerorthe hydrogenated amorphoussilicon layer may be present as multiple layers. Additionally, or alternatively, more layers of other materials may be included within the transparent coating stack. In one example, the transparent coating stack may include a low refractive index material such as silicon dioxide or indium tin oxide (ITO) adjacent to one or more layers of polycrystalline silicon layer or hydrogenated amorphoussilicon. In another embodiment of the disclosure, a visible or infrared monitoring system or sensor may be disposed behind the fourth surface 38. For the visible or infrared monitoringsystem, it may be useful to use fewer layers within the transparent coatingstackresultingin a cheaper overall cost. In some examples, the overall transmission of visible light is higher than 3%, or higher than 5%, or higher than 8%.EXAMPLES

[0024] To measure the optical properties of the transparent coating stack. First, the percentage of reflectance (%R) and transmittance (%T) represent the amount of light that is reflected by a material and passes through a material, respectively. The higher the value of %T, the clearer an object will be; conversely, the lower the %T the more opaque an object will be. Additionally, a value Y relates to the luminance / brightness and a* and b* relate to components of the CIELAB color space and the hue.

[0025] Example 1

[0026] A five-layer prism coating on the second surface was tested using the materials:niobium-pentoxide (Nb2O5), silicon dioxide (SiO2), and silicon (Si). The thickness of each layer and the order of each component are shown below in Table 1. The resulting reflected and transmitted, Y, a*, and b* using cold-silicon and hot-silicon are shown in Table 2 and Table 3 respectively. The experiment for the cold-silicon (Table 2) was performed using standard soda-lime (crown) float glass. The experiment for the hot-silicon (Table 3) was performed using Tirex™ from AGC which has a lower absorbance in the near infrared.

[0027] Table 1

[0028] Table 2

[0029] Table 3

[0030] Example 2

[0031] A three-layer prism coating on the second surface was tested using the materials:polycrystalline or hydrogenated silicon (Si*) and silicon dioxide (SiO2). The thickness of each layer and the order of each component are shown below in Table 4. The resulting reflected and transmitted, Y, a*, and b* are shown in Table 5. The experiment was performed using standard soda-lime (crown) float glass.

[0032] Table 4

[0033] Table 5

[0034] Example 3

[0035] Afive-layercoatingforan electrochromicdevice usingan electrochromic medium (EC) on the fourth surface was tested using the materials: pentoxide (Nb2O5), silicon dioxide (SiO2), and silicon (Si). In addition, a layer of indium tin oxide (ITO) was added on the second and the third surface. The thickness of each layer a nd the order of each component are shown below in Table 6. The resulting reflected and transmitted, Y, a*, and b* are shown in Table 7. The experiment was performed using standard soda-lime (crown) float glass.

[0036] Table 6

[0037] Table 7

[0038] Example 4

[0039] A three-layer coating for an electrochromic device using an electrochromic medium (EC) on the fourth surface was tested using the materials: polycrystalline or hydrogenated silicon (Si*) and silicon dioxide (SiO2). In addition, a layerof indium tin oxide (ITO) was added on the second and the third surface. The thickness of each layer and the order of each component are shown below in Table 8. The resulting reflected and transmitted, Y, a*, and b* are shown in Table 9. The experiment was performed using standard soda-lime (crown) float glass.

[0040] Table8

[0041] Table 9

[0042] Example 5

[0043] A seven-layer coating for an electrochromic device using an electrochromic medium (EC) on the third surface was tested using the materials: pentoxide (Nb2O5), silicon dioxide (SiO2), and silicon (Si). In addition, a layer of indium tin oxide (ITO) was added on the second and the third surface. The thickness of each layer a nd the order of each component a re shown below in Table 10. The resulting reflected and transmitted, Y, a*, and b* are shown in Table 11. The experiment was performed using standard soda-lime (crown) float glass.

[0044] Table 10

[0045] Table 11

[0046] Example 6

[0047] A four-layer coating for an electrochromic device using an electrochromic medium (EC) on the third surface was tested using the materials: silicon dioxide (SiO2), and polycrystallineor hydrogenated silicon (Si*). In addition, a layerof indium tin oxide (ITO) was added on the second and the third surface. The thickness of each layer a nd the order of each component are shown below in Table 12. The resulting reflected and transmitted, Y, a*, and b* are shown in Table 13. The experiment was performed using standard soda-lime (crown) float glass.

[0048] Table 12

[0049] Table 13

[0050] Example 7

[0051] A six-layercoatingfor an electrochromicdevice usingan electrochromic medium (EC) on the third surface was tested using the materials: silicon dioxide (SiO2), and polycrystalline hydrogenated silicon (Si*). In addition, a layer of indium tin oxide (ITO) was added on the second and the third surface. The thickness of each layer and the order of each component are shown below in Table 14. The resulting reflected and transmitted, Y, a*, and b* are shown in Table 15.

[0052] Table 14

[0053] Table 15

[0054] An alternative six-layer coating for the electrochromic device was tested using modified thicknesses. The thickness of each layer a nd the order of each component are shown below in Table 16. The resulting reflected and transmitted, Y, a*, and b* are shown in Table 17.

[0055] Table 16

[0056] Table 17

[0057] It will be understood by one having ordinary skill in the art that construction of the described disclosure and other components is not limited to any specific material. Other exemplary embodiments of the disclosure disclosed herein may be formed from a wide variety of materials, unless described otherwise herein.

[0058] According to one aspect of the present disclosure, a transmissive assembly includes a front substrate defining a first surface and a second surface, and a transparent coating stack comprising one or more silicon-based layers, wherein the one or more silicon-based layers have a high index of refraction and a low absorption of near infrared light.

[0059] According to another aspect of the present disclosure, a rearsubstrate defining a third surface and a fourth surface, the transparent coating stack is disposed on the second, third, or fourth surface, a chamber defined between the second surface and the third surface, and an electro-optic medium disposed in the chamber, wherein the electro-optic medium is operable between a comparatively transmissive state and non-transmissive state.

[0060] According to yet another aspect of the present disclosure, the one or more silicon- based layers comprise a polycrystalline silicon.

[0061] According to another aspect of the present disclosure, the polycrystalline silicon is made by depositing the transparent coating stack as an amorphous layer at high temperatures during deposition.

[0062] Accordingto yet another aspect of the present disclosure, the polycrystalline silicon is made by depositing the transparent coating stack as an amorphous layer followed by an annealing post deposition.

[0063] Accordingto another aspect of the present disclosure, the one or more silicon-based layers comprise hydrogenated amorphous silicon layers.

[0064] According to yet another aspect of the present disclosure, the transparent coating stack comprises three layers.

[0065] According to anotheraspectof the present disclosure, the transmission assembly isa prism mirror.

[0066] Accordingto yet anotheraspectofthe present disclosure, a front substrate defining a first surface and a second surface, the second surface comprises a first electrically conductive layer, a rear substrate defininga third surface and a fourth surface, the third surface includes a second electrically conductive layer, an electro-optic medium disposed betweenthe second surface and the third surface, and a series of clear mirror stacks comprising a silicon-based material.

[0067] Accordingto another aspect of the present disclosure, the series of clear mirror stacks further includes layers of niobium pentoxide or an equivalent high-index material, and / or indium tin oxide.

[0068] According to yet another aspect of the present disclosure, the series of clear mirror stacks is disposed on the second surface, the third surface, and / or the fourth surface.

[0069] Accordingto another aspect of the present disclosure, the series of clear mirror stacks further comprises layers of silicon dioxide.

[0070] According to yet another aspect of the present disclosure, the series of clear mirror stacks comprises between 3-7 layers.

[0071] Accordingto another aspect of the present disclosure, the series of clear mirror stacks comprises at least one layer of hydrogenated amorphous silicon.

[0072] According to yet another aspect of the present disclosure, the at least one layer of amorphous hydrogenated silicon is between 16 nm and 31 nm.

[0073] Accordingto another aspect of the present disclosure, the series of clear mirror stacks includes at least one layer of polycrystalline silicon.

[0074] According to yet another aspect of the present disclosure, the at least one layer of polycrystalline silicon is between 16 nm and 31 nm.

[0075] Accordingto anotheraspectofthe present disclosure, the electro-opticdevice further includes a first layer of indium tin oxide, a second layer of indium tin oxide, a first layer of niobium-pentoxide oran equivalent high-index material, a first layerof silicon dioxide, a layer of polycrystalline silicon, a second layer of silicon dioxide, and a second layer of niobiumpentoxide or an equivalent high-index material.

[0076] According to yet another aspect of the present disclosure, the electro-optic device further includes a first layerof indium tin oxide, a second layerof indium tin oxide, a first layerof niobium-pentoxide or an equivalent high-index material, a first layer of silicon dioxide, a layer of hydrogenated silicon, a second layer of silicon dioxide, and a second layer of niobiumpentoxide or an equivalent high-index material.

[0077] According to another aspect of the present disclosure, the series of clear mirror stacks includes a layer of niobium-pentoxide or an equivalent high-index material, a first layer of silicon dioxide, a layerof polycrystalline silicon, a second layerof silicon dioxide, and a second layer of niobium-pentoxide or an equivalent high-index material.

[0078] According to yet another aspect of the present disclosure, the series of clear mirror stacks includes a layerof niobium-pentoxide oran equivalent high-index material, a first layer of silicon dioxide, a layer of hydrogenated silicon, a second layer of silicon dioxide, and a second layer of niobium-pentoxide or an equivalent high-index material.

[0079] According to another aspect of the present disclosure, a first layerof a silicon-based material, a layer of silicon dioxide, and a second layer of a silicon-base material, the first and second layers of a silicon-based material have a high index of refraction and a low absorption of light in approximately 800-1000 nm, the transparent coating stack is disposed onto a substrate, the first and second layers of a silicon-based material are between 16 nm and 31 nm thick.

[0080] According to yet another aspect of the present disclosure, the transparent coating stack further includes a layer of niobium-pentoxide or an equivalent high-index material disposed on the layer of silicon dioxide.

[0081] According to another aspect of the present disclosure, the transparent coating stack further includes a layer of indium tin oxide disposed on either the substrate or the first layer of a silicon-based material.

[0082] According to yet another aspect of the present disclosure, transparent coating stack is in an electro-optic device.

[0083] According to another aspect of the present disclosure, the electro-optic device has a transmittance at 940 nm between 65-75%.

[0084] According to yet another aspect of the present disclosure, the transparent coating stack includes the substrate, a first layer of hydrogenated silicon, a layer of silicon dioxide, and a second layer of hydrogenated silicon.

[0085] According to another aspect of the present disclosure, the substrate is glass, plastic, or other optically transparent material.

[0086] According to yet another aspect of the present disclosure, the substrate is soda lime glass.

[0087] Accordingto another aspect of the present disclosure, the substrate is a low iron glass.

[0088] For purposes of this disclosure, the term "coupled" (in all of its forms, couple, coupling, coupled, etc.) generally means the joining of two components (electrical or mechanical) directly or indirectly to one another. Such joining may be stationary in nature or movable in nature. Such joining may be achieved with the two components (electrical or mechanical) and any additional intermediate members being integrally formed as a single unitary body with one another or with the two components. Such joining may be permanent in nature or may be removable or releasable in nature unless otherwise stated.

[0089] It is also important to note that the construction and arrangement of the elements of the disclosure, as shown in the exemplary embodiments, is illustrative only. Although only a few embodiments of the present innovations have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter recited. For example, elements shown as integrally formed may be constructed of multiple parts, or elements shown as multiple parts may be integrally formed, the operation of the interfaces may be reversed or otherwise varied, the length or width of the structures and / or members or connector or other elements of the system may be varied, the nature or number of adjustment positions provided between the elements may be varied. It should be noted that the elements and / or assemblies of the system may be constructed from any of a wide variety of materials that provide sufficient strength or durability, in any of a wide variety of colors, textures, and combinations. Accordingly, all such modifications are intended to be included within the scope of the present innovations. Other substitutions, modifications, changes, and omissions may be made in the design, operating conditions, and arrangement of the desired and other exemplary embodiments without departing from the spirit of the present innovations.

[0090] It will be understood thatanydescribed processesorstepswithindescribed processes may be combined with other disclosed processes or steps to form structures within the scopeof the present disclosure. The exemplary structures and processes disclosed herein are for illustrative purposes and are not to be construed as limiting.

Claims

What is claimed is:

1. A transmissive assembly comprising:a front substrate defining a first surface and a second surface; anda transparent coati ng stack comprising one or more silicon-based layers, wherein the one or more silicon-based layers have a high index of refraction and a low absorptionof near infrared light.

2. A transmissive assembly of claim 1, further comprising:a rear substrate defining a third surface and a fourth surface; wherein the transparent coating stack is disposed on the second, third, or fourth surface;a chamber defined between the second surface and the third surface; and an electro-optic medium disposed in the chamber, wherein the electro-optic medium is operable between a comparatively transmissive state and non-transmissive state.

3. The transmissive assembly of claim 1, wherein the one or more silicon-based layers comprise a polycrystalline silicon.

4. The transmissive assembly of claim 3, wherein the polycrystalline silicon is made by depositingthe transparent coati ng stack as an amorphous layer at high temperatures during deposition.

5. The transmissive assembly of claim 3, wherein the polycrystalline silicon is made by depositingthe transparent coatingstackas an amorphous layerfollowed by an annealing post deposition.

6. The transmissive assembly of claim 1, wherein the one or more silicon-based layers comprise hydrogenated amorphous silicon layers.

7. The transmissive assembly of any one of the claims 1-6, wherein the transparent coating stack comprises three layers.

8. The transmissive assembly of any one of the claims 3-6, wherein said transmission assembly is a prism mirror.

9. An electro-optic device, comprising:a front substrate defining a first surface and a second surface, wherein the second surface comprises a first electrically conductive layer;a rear substrate defining a third surface a nd a fourth surface; wherein the third surface comprises a second electrically conductive layer;an electro-optic medium disposed between the second surface and the third surface; anda series of clear mirror stacks comprising a silicon-based material.

10. The electro-optic device of claim 9, wherein the series of clear mirror stacks further comprises layers of niobium pentoxide or an equivalent high-index material, and / or indium tin oxide.

11. The electro-optic device of either claim 9 or 10, wherein the series of clear mirror stacks is disposed on the second surface, the third surface, and / or the fourth surface.

12. The electro-opticdevice of any one of claims 9-11, wherein the series of clear mirror stacks further comprises layers of silicon dioxide.

13. The electro-opticdevice of any one of claims 9-12, wherein the series of clear mirror stacks comprises between 3-7 layers.

14. The electro-optic device of any one of the claims 9-13, wherein the series of clear mirror stacks comprises at least one layer of hydrogenated amorphous silicon.

15. The electro-optic device of claim 14, wherein the at least one layer of amorphous hydrogenated silicon is between 16 nm and 31 nm.

16. The electro-optic device of any one of the claims 9-13, wherein the series of clear mirror stacks comprises at least one layer of polycrystalline silicon.

17. The electro-optic device of claim 16, wherein the at least one layer of polycrystalline silicon is between 16 nm and 31 nm.

18. The electro-optic device of claim 9, wherein the electro-optic device further comprises:a first layer of indium tin oxide;a second layer of indium tin oxide;a first layer of niobium-pentoxide or an equivalent high-index material;a first layer of silicon dioxide;a layer of polycrystalline silicon;a second layer of silicon dioxide; anda second layer of niobium-pentoxide or an equivalent high-index material.

19. The electro-optic device of claim 9, wherein the electro-optic device further comprises:a first layer of indium tin oxide;a second layer of indium tin oxide;a first layer of niobium-pentoxide or an equivalent high-index material;a first layer of silicon dioxide;a layer of hydrogenated silicon;a second layer of silicon dioxide; anda second layer of niobium-pentoxide or an equivalent high-index material.

20. The electro-optic device of claim 9, wherein the series of clear mirror stacks comprises:a layer of niobium-pentoxide or an equivalent high-index material;a first layer of silicon dioxide;a layer of polycrystalline silicon;a second layer of silicon dioxide; anda second layer of niobium-pentoxide or an equivalent high-index material.

21. The electro-optic device of claim 9, wherein the series of clear mirror stacks comprises:a layer of niobium-pentoxide or an equivalent high-index material;a first layer of silicon dioxide;a layer of hydrogenated silicon;a second layer of silicon dioxide; anda second layer of niobium-pentoxide or an equivalent high-index material.

22. A transparent coating stack comprising:a first layer of a silicon-based material;a layer of silicon dioxide; anda second layer of a silicon-base material, wherein the first and second layers of a silicon-based material have a high index of refraction and a low absorption of light in approximately 800-1000 nm, wherein the transparent coating stack is disposed onto a substrate, wherein the first and second layers of a silicon-based material are between 16 nm and 31 nm thick.

23. The transparent coating stack of claim 22, further comprising:a layer of niobium-pentoxide or an equivalent high-index material disposed on the layer of silicon dioxide.

24. The transparent coating stack of either one of claims 22 and 23, further comprising:a layer of indium tin oxide disposed on either the substrate or the first layer of a silicon-based material.

25. The transparent coati ng stack of claim 22, wherein said transparent coating stack is in an electro-optic device.

26. The transparent coating stack of claim 25, wherein the electro-optic device has a transmittance at 940 nm between 65-75%.

27. The transparent coating stack of claim 22, wherein said transparent coating stack comprises:a substrate;a first layer of hydrogenated silicon;a layer of silicon dioxide; anda second layer of hydrogenated silicon.

28. The transparent coating stack of claim 22, wherein said transparent coating stack comprises:a substrate;a first layer of polycrystalline silicon;a layer of silicon dioxide; anda second layer of polycrystalline silicon.

29. Thetransparent coati ng stack of any one of the claims 22-28, wherein the substrate is glass, plastic, or other optically transparent material.

30. The transparent coating stack of claim 29, wherein the substrate is soda lime glass.

31. The transparent coating stack of claim 29, wherein the substrate is a low iron glass.

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