A textured region that reduces specular reflection, comprising a low refractive index substrate having high-altitude and low-altitude surfaces, and a high refractive index material disposed on the low-altitude surface.

Abstract

A display article substrate comprises: (a) a major surface; and (b) a textured region on at least a portion of the major surface, the textured region including: (i) one or more high planes located at a high mean altitude parallel to a reference plane extending through the substrate below the textured region; (ii) one or more low planes located at a low mean altitude parallel to the reference plane that is lower than the high mean altitude; and (iii) a high refractive index material disposed on each of the one or more low planes located at the low mean altitudes to form one or more median planes located at a median mean altitude parallel to the reference plane that is higher than the low mean altitude and lower than the high mean altitude, the high refractive index material having a refractive index higher than the refractive index of the substrate.

Description

Priority Claim

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 049843 filed on 9 July 2021, and all contents of this Provisional Application shall constitute part of this Specification by reference. Cross-references to related applications

[0002] This application is owned by the same assignee and is based on U.S. Patent Application No. __________ (D31038 / 32632) (Title of Invention: "ANTI-GLARE SUBSTRATE FOR A DISPLAY ARTICLE INCLUDING A TEXTURED REGION WITH PRIMARY SURFACE FEATURES AND SECONDARY SURFACE FEATURES IMPARTING A SURFACE ROUGHNESS THAT INCREASES SURFACE SCATTERING") and U.S. Patent Application No. __________ (D32630 / 32632) (Title of Invention: "TEXTURED REGION OF A SUBSTRATE TO REDUCE SPECULAR REFLECTANCE INCORPORATING SURFACE FEATURES WITH AN ELLIPTICAL PERIMETER OR SEGMENTS THEREOF, AND METHOD OF MAKING THE This invention relates to the same U.S. Patent Application No. __________ (D32647) (title of invention "DISPLAY ARTICLES WITH DIFFRACTIVE, ANTIGLARE SURFACES AND THIN, DURABLE ANTIREFLECTION COATINGS", filing date ______________), and U.S. Patent Application No. __________ (D32623) (title of invention "DISPLAY ARTICLES WITH DIFFRACTIVE, ANTIGLARE SURFACES AND THIN, DURABLE ANTIREFLECTION COATINGS", filing date ______________), but does not claim priority thereto. All disclosures in the above U.S. Patent Application specifications, publications and patent documents shall, by reference, form part of this specification. [Technical Field]

[0003] The present disclosure relates to a substrate for a display article having a texture region that reduces specular reflection, including a low refractive index substrate having a high altitude surface and a low altitude surface, and a high refractive index material disposed on the low altitude surface.

Background Art

[0004] For the purpose of covering the display of a display article, a substrate transparent to visible light is used. Such display articles include smartphones, tablet terminals, televisions, computer monitors, and the like. Further, as the display, a liquid crystal display and an organic light emitting diode display are particularly often used. This substrate protects the display and at the same time enables the user to view the display due to the transparency of the substrate.

[0005] When the substrate reflects external light, particularly specularly, the visibility of the display through the substrate decreases. Specular reflection here refers to the reflection of external light by the substrate like a mirror. For example, the substrate may reflect visible light reflected or emitted from an object in the surrounding environment of the device. When the substrate reflects visible light, the contrast of the light transmitted through the substrate from the display and entering the user's eyes decreases. Further, depending on the viewing angle, instead of the visible light emitted from the display, a specularly reflected image may be seen by the user. Therefore, attempts have been made to reduce the specular reflection of visible external light by the substrate.

[0006] Attempts to reduce specular reflection on substrates have been made by adding texture to the reflective surface of the substrate. The resulting surface is sometimes called an "antiglare surface." For example, texture can be added to the surface of a substrate by sandblasting or liquid etching, which typically causes the surface to reflect ambient light more diffusely than specularly. Diffuse reflection generally refers to the phenomenon where the intensity of ambient light reflected by a reflective surface does not change, but the texture of the reflective surface causes it to be reflected as scattered light. The more diffuse reflection there is, the less it interferes with the user's visibility of the visible light emitted by the display.

[0007] However, the texture application methods described above (i.e., sandblasting and liquid etching) generate feature areas on the surface with unclear and unreproducible geometry (the texture is obtained from these feature areas). The geometry of the textured surface of one substrate formed by sandblasting or liquid etching can never perfectly match the geometry of the textured surface of another substrate formed by sandblasting or liquid etching. Generally, the reproducible target in this texture application process is a quantified representation of the surface roughness of the textured surface of the substrate (i.e., R a ) was limited to.

[0008] Various evaluation criteria are used to assess the quality of an "antiglare" surface. These criteria include (1) distinctness-of-image, (2) pixel power deviation, (3) visible moiré interference fringes, (4) transmitted haze, (5) specular reflection reduction, and (6) reflective color artifacts. Discreteness-of-image, which might be more accurately called distinctness-of-reflected-image, is an indicator of how clearly the image reflected from the surface appears. Textured surfaces with low discreetness-of-image tend to have a higher degree of diffuse reflection than specular reflection. Surface features can also make various pixels on the display appear larger, potentially causing users to perceive distorted images. Pixel power deviation, also known as "sparkle," is a quantitative measure of this effect. A lower pixel power deviation is better. Moiré interference fringes are large interference patterns, and when moiré interference fringes are visible, the image seen by the user becomes distorted. It is preferable that the textured surface does not generate visible moiré interference fringes. Transmitted haze is an indicator of how much visible light emitted by the display is diffused by the textured surface as it passes through the substrate. When the transmitted haze increases, the sharpness of the display decreases (i.e., the apparent resolution decreases). Specular reflection reduction is an indicator of how much the anti-glare surface can reduce the specular reflection of ambient light compared to a baseline non-anti-glare glass substrate. A larger specular reflection reduction from the baseline is better. Reflected color artifact is a type of chromatic aberration in which the reflected light is relatively diffused but appears separated by color due to diffraction as a function of wavelength when reflected by the textured surface. The weaker the reflected color artifact on the textured surface, the better. Some of these characteristics will be described in detail later.

[0009] However, simply targeting a specific surface roughness level did not allow for the simultaneous optimization of all the above indicators. While increasing surface roughness relatively through sandblasting or liquid etching might allow for a proper conversion of specular reflection to diffuse reflection, higher surface roughness can lead to increased transmission haze and pixel power deviation. On the other hand, if the surface roughness is relatively low, transmission haze decreases, but it may not be possible to sufficiently convert specular reflection to diffuse reflection, potentially failing to achieve the "anti-glare" effect intended by texture application. [Overview of the project] [Problems that the invention aims to solve]

[0010] Therefore, there is a need for a new method for creating textured areas on substrates, that is, a method that is reproducible between substrates and makes the textured surface an "anti-glare" surface (e.g., low image sharpness, low specular reflection) by reflecting ambient light more effectively by diffuse reflection than by specular reflection, while simultaneously achieving low pixel power deviation, low transmission haze, and low reflective color artifacts. [Means for solving the problem]

[0011] This disclosure provides a novel method for simultaneously achieving many desired anti-glare performance indicators. A textured region is formed on the main surface of the substrate, and in the textured region, multiple surfaces are provided on the substrate at two different average heights by forming surface features on the substrate using methods such as etching. A high refractive index material is then deposited on the substrate surface located at the lower of the two different average heights. At this time, the amount of high refractive index material deposited is set so that it does not reach the substrate surface located at the higher of the two different average heights. The surface features can be arranged randomly but at specific positions, thereby achieving reproducibility between substrates. The surface features can have adjustable characteristic dimensions to obtain the desired optical results. In general, the presence of high refractive index material reduces pixel power deviation, and the presence of surface features scatters reflected light, resulting in a reduction of specular reflection.

[0012] A substrate for a display article is provided, comprising: (a) a main surface; and (b) a texture region provided on at least a portion of the main surface, the texture region comprising: (i) one or more high surfaces located at a high mean height parallel to a reference plane and extending below the texture region through the substrate; (ii) one or more low surfaces located at a low mean height parallel to the reference plane and lower than the high mean height; and (iii) one or more medium surfaces arranged on each of the one or more low surfaces located at the low mean height and located at a medium mean height parallel to the reference plane, which is higher than the low mean height and lower than the high mean height, and the high refractive index material having a refractive index higher than the refractive index of the substrate or the low refractive index material forming one or more high surfaces.

[0013] According to a second aspect of this disclosure, in the substrate described in the first aspect, (i) the median mean height of the high refractive index material is lower than the high mean height of one or more high surfaces by a distance in the range of 100 nm to 190 nm, (ii) the low mean height of one or more low surfaces is lower than the high mean height of one or more high surfaces by a distance in the range of 220 nm to 370 nm, and (iii) the median mean height of the high refractive index material is higher than the low mean height of one or more low surfaces by a distance in the range of 100 nm to 200 nm.

[0014] According to a third aspect of this disclosure, in the substrate described in the first or second aspect, (i) the refractive index of the substrate or low refractive index material is in the range of 1.4 to 1.6, and (ii) the refractive index of the high refractive index material is in the range of 1.6 to 2.3.

[0015] According to a fourth aspect of this disclosure, in the substrate described in any one of the first to third aspects, the high refractive index material is an area on a plane that is (i) parallel to a reference plane and (ii) extends through the high refractive index material, and which comprises 22% to 49% of the area defined by the texture region.

[0016] According to the fifth aspect of this disclosure, in the substrate described in any one of the first to fourth aspects, the substrate includes a glass substrate or a glass ceramic substrate.

[0017] According to a sixth aspect of the present disclosure, a substrate for a display article, comprising: (i) a main surface; and (ii) a textured region provided on at least a portion of the main surface, wherein (a) one or more high surfaces located at a high mean height parallel to a reference plane and extending below the textured region through the substrate; (b) one or more low surfaces located at a low mean height parallel to the reference plane and lower than the high mean height; and (c) a surface feature portion provided so as to protrude from or be recessed from the peripheral portion of the main surface, wherein the surface feature portion comprises one or more high surfaces and one or more A substrate is provided, comprising: (ii) a surface feature portion that forms one of the lower surfaces, and whose peripheral portion forms the other surface among one or more higher surfaces and one or more lower surfaces that is different from the surface feature portion; and (d) a texture region comprising a high refractive index material disposed on one or more lower surfaces located at a lower mean height, which has a refractive index higher than the refractive index of the substrate or the low refractive index material forming one or more higher surfaces, and (ii) one or more intermediate surfaces located at an intermediate mean height parallel to a reference plane, between the higher mean height and the lower mean height.

[0018] According to a seventh aspect of this disclosure, in the substrate described in the sixth aspect, (i) the surface feature portion is provided so as to be recessed from the peripheral portion, and (ii) the high refractive index material is arranged on one or more lower surfaces located at the lower mean height of the surface feature portion within each surface feature portion.

[0019] According to the eighth aspect of this disclosure, in the substrate described in the sixth or seventh aspect, the median mean height of the high refractive index material is lower than the high mean height of one or more high surfaces by a distance in the range of 120 nm to 190 nm.

[0020] According to the ninth aspect of this disclosure, in the substrate described in any one of the sixth to eighth aspects, the lower mean elevation is lower than the higher mean elevation by a distance in the range of 220 nm to 370 nm.

[0021] According to the tenth aspect of this disclosure, in the substrate described in any one of the sixth to ninth aspects, the median mean height of the high refractive index material is higher than the lower mean height of one or more lower surfaces by a distance in the range of 100 nm to 200 nm.

[0022] According to the eleventh aspect of this disclosure, in the substrate described in any one of the sixth to tenth aspects, the refractive index of the substrate or low refractive index material is in the range of 1.4 to 1.6.

[0023] According to the twelfth aspect of this disclosure, in the substrate described in any one of the sixth to eleventh aspects, the refractive index of the high refractive index material is in the range of 1.6 to 2.3.

[0024] According to the 13th aspect of this disclosure, in the substrate described in any one of the 6th to 12th aspects, (i) each surface feature portion has an outer circumference parallel to a reference plane, and (ii) the outer circumference of each surface feature portion is circular or elliptical.

[0025] According to a fourteenth aspect of this disclosure, in a substrate described in any one of the sixth to twelfth aspects, (i) each surface feature portion has an outer circumference parallel to a reference plane, and (ii) the outer circumference of each surface feature portion has a maximum dimension in the range of 5 μm to 200 μm.

[0026] According to the 15th aspect of this disclosure, in the substrate described in any one of the 6th to 14th aspects, the arrangement of surface features is not a repeating arrangement but an arrangement that reflects a random distribution.

[0027] According to the sixteenth aspect of this disclosure, in the substrate described in any one of the sixth to fourteenth aspects, the surface feature portions are arranged in a random distribution such that the distance between the surface feature portions satisfies the minimum center-to-center distance.

[0028] According to the 17th aspect of this disclosure, in the substrate described in any one of the 6th to 16th aspects, the high refractive index material is AlN x SiOx N y , or SiN x Includes.

[0029] According to the 18th aspect of this disclosure, in the substrate according to any one of the 6th to 17th aspects, the high refractive index material is an area on a plane that is (i) parallel to a reference plane and (ii) extends through the high refractive index material, and which comprises 22% to 49% of the area defined by the texture region.

[0030] According to the 19th aspect of this disclosure, in the substrate described in any one of the 6th to 18th aspects, the substrate includes a glass substrate or a glass ceramic substrate.

[0031] According to the 20th aspect of this disclosure, in the substrate described in any one of the 6th to 19th aspects, (i) the textured area exhibits a pixel power deviation in the range of 1.2% to 2.1%, (ii) the textured area exhibits a transmission haze in the range of 1.5% to 2.5%, (iii) the textured area exhibits a specular reflectance in the range of 0.5% to 1.75%, and (iv) the textured area exhibits an image sharpness in the range of 25% to 85%.

[0032] According to a 21st aspect of the present disclosure, a method for forming a textured area of ​​a substrate for a display article, comprising the steps of (a) forming a textured area on the main surface of the substrate, in accordance with a predetermined positioning of each surface feature portion, the surface feature portion being recessed from or protruding from the periphery, wherein (i) one or more high surfaces of the textured area are located at a high mean height parallel to a reference plane provided to extend below the textured area through the substrate, (ii) one or more low surfaces of the textured area are located at a low mean height parallel to the reference plane, which is lower than the high mean height, and (iii) the surface feature portion A method is provided comprising the steps of (iv) forming a surface feature portion which has one of one or more high-level surfaces and one or more low-level surfaces, and whose peripheral portion has the other of the one or more high-level surfaces and one or more low-level surfaces which is different from the surface feature portion which has the surface feature portion; and (b) depositing a high refractive index material on the portion of the surface feature portion and the peripheral portion which has one or more low-level surfaces located at a low mean altitude, wherein the high refractive index material has (i) a refractive index higher than the refractive index of the substrate, and (ii) one or more intermediate surfaces located at a mid mean altitude parallel to a reference plane, between the high mean altitude and the low mean altitude.

[0033] According to a 22nd aspect of the present disclosure, the method according to the 21st aspect further includes the step of establishing a predetermined position for each surface feature by determining the position of each surface feature using a spacing distribution algorithm.

[0034] According to a 23rd aspect of the present disclosure, the method according to the 22nd aspect further includes the step of placing on a main surface an etching mask that prevents etching at locations where a surface feature is to be formed according to a predetermined positioning of the surface feature, or (ii) an etching mask that allows etching only at locations where a surface feature is to be formed according to a predetermined positioning of the surface feature, wherein the step of forming the surface feature includes bringing at least the main surface of the substrate into contact with an etching solution with the etching mask placed on the main surface of the substrate.

[0035] According to a 24th aspect of this disclosure, in the method of the 23rd aspect, the step of depositing a high refractive index material is performed after the surface feature portion has been formed and with the etching mask placed on the main surface.

[0036] According to a 25th aspect of the present disclosure, the method according to the 24th aspect further includes the step of removing an etching mask after depositing a high refractive index material. [Brief explanation of the drawing]

[0037] [Figure 1] A perspective view of a display article of the present disclosure, showing a substrate having a textured area for reducing the specular reflectivity of light emitted from the external environment. [Figure 2] This figure shows scan images of the optical profilometer according to Examples 2A to 2G, and provides an overview of the embodiment of a texture region including one or more surfaces located at an average height higher than the reference plane, and a high refractive index material deposited within the surface feature area to form a surface located at an average height in the middle of the reference plane. [Figure 3A] Figure 2 shows an elevation view of the section taken along line III-III, illustrating a substrate provided with a surface located at a high mean altitude, a surface located at a lower mean altitude from the reference plane, and a high refractive index material positioned on the surface at the lower mean altitude, forming a surface at a mid-mean altitude between the high and low mean altitudes. [Figure 3B] This figure is similar to Figure 3A, but the surface feature area protrudes from the periphery of the substrate (as in Figure 3A), rather than being recessed from the periphery, illustrating the case where the high refractive index material is placed on the periphery. [Figure 4] Diagrams related to the calculation of hexagonal degrees [Figure 5] A schematic diagram illustrating a method for forming the texture region embodiment shown in Figure 1, including the steps of determining the position of the surface feature portion, placing an etching mask on the substrate so that the surface feature portion can be formed at the determined position, depositing a high refractive index material on the substrate while the etching mask is on the substrate, and then removing the etching mask. [Figure 6A]A graph showing the diffraction efficiency of light transmitted through the texture region of the substrate in Comparative Example 1A as a function of trench depth (i.e., the distance between the higher mean altitude and the lower mean altitude). [Figure 6B] A graph showing the diffraction efficiency of light reflected from the textured region of the substrate as a function of trench depth, relating to Comparative Example 1A. [Figure 7A] A graph showing the diffraction efficiency of light transmitted through the textured region of the substrate as a function of trench depth, relating to Example 1B. [Figure 7B] A graph showing the diffraction efficiency of light reflected from the textured region of the substrate as a function of trench depth, relating to Example 1B. [Figure 7C] A graph showing the diffraction efficiency of light passing through the texture region of the substrate in Example 1B as a function of the substrate's packing density (i.e., the proportion of the plane through which the high refractive index material of the texture region passes). [Figure 7D] A graph showing the diffraction efficiency of light reflected from the textured region of the substrate in Example 1B as a function of the substrate's filling density (i.e., the proportion of the plane through which the high refractive index material of the textured region passes). [Figure 7E] A graph showing the diffraction efficiency of light reflected from the textured region of the substrate as a function of the incident light angle, relating to Example 1B. [Figure 7F] A graph showing the diffraction efficiency of light transmitted through the texture region of the substrate as a function of the incident light angle, according to Example 1B. [Figure 8] Histograms showing the distance between the centers of objects randomly placed within an area using a spacing distribution algorithm (to determine the arrangement of surface features of the textured area to be formed in a subsequent process) in Examples 2A to 2G. [Figure 9] Histograms showing the distance between the centers of objects randomly placed within an area using other spacing distribution algorithms (in order to determine the arrangement of surface features of the textured area to be formed in a subsequent process) relating to Examples 3A to 3D. [Modes for carrying out the invention]

[0038] Referring to Figure 1, the display article 10 includes a substrate 12. In some embodiments, the display article 10 further includes a housing 14 to which the substrate 12 is attached, and a display 16 inside the housing 14. In such embodiments, the substrate 12 covers at least a portion of the display 16 so that light emitted from the display 16 passes through the substrate 12.

[0039] The substrate 12 has a main surface 18, a textured area 20 defined on the main surface 18, and a thickness 22 whose area is partially defined by the main surface 18. Typically, the main surface 18 faces the direction of the external environment 24 surrounding the display item 10 and toward the distal side of the display 16. The display 16 emits visible light that passes through the thickness 22 of the substrate 12 and exits from the main surface 18 into the external environment 24.

[0040] Referring to Figures 2 to 3B, in several embodiments, the textured region 20 has one or more higher surfaces 26. The higher surfaces 26 face the external environment 24 and are located at a higher mean elevation 28. The base-plane 30 extends below the textured region 20, passing through the substrate 12. The higher mean elevation 28 is parallel to the base-plane 30. Note that the base-plane 30 provides a conceptual reference position and is not a structural feature. Each of the one or more higher surfaces 26 is located near this higher mean elevation 28 within the manufacturing capacity.

[0041] The textured area has one or more lower surfaces 32. The lower surfaces 32 face the external environment 24 and are located at a lower mean elevation 34. The lower mean elevation 34 is parallel to the reference plane 30 and lower than the higher mean elevation 28. Therefore, "higher" and "lower" are terms that indicate relative elevation from the reference plane 30. Any one or more lower surfaces 32 are located near this lower mean elevation 34 within the manufacturing capacity.

[0042] One or more upper surfaces 26 of the texture region 20 are obtained by the substrate 12 or a low refractive index material disposed on the substrate 12. In such an embodiment, among the substrate 12 and the low refractive index material, the one forming one or more upper surfaces 26 has a refractive index of 1.4, 1.5, 1.6, or within the range of 1.4 to 1.6. In a plurality of embodiments, regardless of whether the substrate 12 forms one or more upper surfaces 26, the substrate 12 has a refractive index of 1.4, 1.5, 1.6, or within the range of 1.4 to 1.6. For the purposes of the present invention, any specific refractive index value is a refractive index value at a wavelength of 589 nm and a temperature of 25°C. <> <>

[0043] <> Also, the texture region 20 further includes a high refractive index material 36. In a plurality of embodiments, the high refractive index material 36 has a composition different from that of the substrate 12. The high refractive index materials 36 are respectively disposed on one or more lower surfaces 32 of the texture region 20 located at the lower average height 34. The high refractive index material 36 forms one or more intermediate surfaces 38. The intermediate surface 38 faces the external environment 24 and is located at an intermediate mean elevation 40 parallel to the reference plane 30. Any of the one or more intermediate surfaces 38 is located near this intermediate mean elevation 40 within the range of manufacturing capabilities. <> <>

[0044] <> The high refractive index material 36 has a refractive index. The refractive index of the high refractive index material 36 is higher than the refractive index of the substrate 12. In a plurality of embodiments, the refractive index of the high refractive index material 36 is 1.6, 1.7, 1.8, 1.9, 2.0, 2.01, 2.02, 2.03, 2.04, 2.05, 2.06, 2.07, 2.08, 2.09, 2.1, 2.2, 2.3, or within any range having any two of these values as upper and lower limit values (for example, among 1.6 to 2.3, 1.8 to 2.2, 1.9 to 2.1, etc.). In a plurality of embodiments, the high refractive index material is Si <> u Al <> v O <> x N<> y , Ta2O5, Nb2O5, AlN <> xSi3N4, AlO x N y SiO x N y SiN x SiN x :H y , HfO2, TiO2, ZrO2, Y2O3, Al2O3, MoO3, and diamond-like carbon, or comprising these. In several embodiments, the high refractive index material is AlN x SiO x N y , or SiN x It is or includes the above. In some embodiments, the high refractive index material is AlN x It is or includes the same. Furthermore, those skilled in the art will understand that the material "AlN" in this disclosure is not a material of the same nature as the material of the present disclosure. x "AlO x N y "SiO x N y ", and "SiN x This can be referred to as a category of material without specifying a particular value with a subscript. Furthermore, the refractive index of high refractive index materials can be adjusted by adjusting the ratio of oxygen and nitrogen through routine experiments. In embodiments where it is desired to have a high refractive index of the film (e.g., 1.8, 1.9 or higher), SiN has a composition close to Si3N4. x In some cases, this is preferable. Also, AlN having a composition close to that of AlN x These may also be preferred as films with similarly high refractive indices. Furthermore, small amounts (e.g., 0-20 atomic%) of oxygen or hydrogen can be incorporated into these materials while achieving a similar high refractive index range.

[0045] The median mean altitude 40 of one or more median surfaces 38 of the high refractive index material 36 is higher than the low mean altitude 34 of one or more low surfaces 32 of the texture region 20, but lower than the high mean altitude 28 of one or more high surfaces 26 of the texture region 20. In short, the median mean altitude 40 is the altitude between the high mean altitude 28 and the low mean altitude 34.

[0046] The mean high altitude 28 of one or more high-altitude surfaces 26 of the texture region 20 is higher by a distance 42 than the mean low altitude 34 of one or more low-altitude surfaces 32 of the texture region 20. In this disclosure, the distance 42 may be referred to as the "trench depth" (but should not be confused with the "air trench depth" described later). In several embodiments, the distance 42 is 220nm, 230nm, 240nm, 250nm, 260nm, 270nm, 280nm, 290nm, 300nm, 310nm, 320nm, 330nm, 340nm, 350nm, 360nm, or 370nm, or any range with any two of these values ​​as upper and lower limits (e.g., 250nm to 350nm, 270nm to 330nm, 220nm to 370nm, etc.).

[0047] The median mean height 40 of the high refractive index material 36 is a distance 44 higher than the lower mean height 34 of one or more lower surfaces 32 of the texture region 20. The distance 44 can also be called the "height" or "thickness" of the high refractive index material 36 deposited on one or more lower surfaces 32. In several embodiments, the distance 44 is 100 nm, 110 nm, 120 nm, 130 nm, 140 nm, 150 nm, 160 nm, 170 nm, 180 nm, 190 nm, or 200 nm, or any range with any two of these values ​​as upper and lower limits (e.g., 100 nm to 200 nm, 120 nm to 180 nm, etc.).

[0048] The median mean height 40 of the high refractive index material 36 is lower by a distance 46 than the high mean height 28 of one or more high surfaces 26 of the texture region 20. In this disclosure, this distance 46 may be referred to as the "air trench depth". In several embodiments, the distance 46 is 100 nm, 110 nm, 120 nm, 125 nm, 130 nm, 140 nm, 150 nm, 160 nm, 170 nm, 180 nm, or 190 nm, or any range with any two of these values ​​as upper and lower limits (e.g., 120 nm to 190 nm, 125 nm to 190 nm, 130 nm to 180 nm, 100 nm to 190 nm, etc.). Note that Figures 3A and 3B are not to scale.

[0049] The high refractive index material 36 occupies a portion of an area 48 on a plane 50 that (i) is parallel to the reference plane 30 and (ii) extends through the high refractive index material 36. The extent of area 48 is defined by the texture region 20. In other words, area 48 does not extend beyond the texture region 20 in the creepage direction. In this specification, the proportion of the high refractive index material 36 in area 48 on plane 50 may be referred to as the "fill-fraction" of the high refractive index material 36. In several embodiments, the filling density of the high refractive index material 36 is 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, or 49%, or any range with any two of these values ​​as upper and lower limits (for example, 44% to 45%, 22% to 49%, etc.). The difference obtained by subtracting the filling density of the high refractive index material 36 from 100% is the filling density of the substrate 12 (or the low refractive index material deposited on the substrate 12) having a lower refractive index than the high refractive index material 36.

[0050] It is believed that the specular reflectivity and first-order diffraction peak intensity are minimized when the filling density of the high-refractive-index material is between 22% and 49%. Since the high-refractive-index material 36 has a higher refractive index than the substrate 12 or the low-refractive-index material, the high-refractive-index material 36 has a higher reflectivity. Therefore, in order to maximize the canceling interference during reflection, the proportion of the high-refractive-index material 36 in the texture region 20 of the main surface 18 that reflects ambient light should be less than half. To balance this with the higher reflectivity of the high-refractive-index material 36, it is necessary to make more than half of the texture region 20 of the main surface 18 that reflects ambient light the substrate 12 or the low-refractive-index material with a lower refractive index.

[0051] In several embodiments, the textured region 20 has surface feature portions 52. In several embodiments, the surface feature portions 52 protrude from the peripheral portion 54 of the textured region 20 of the main surface 18. Such surface feature portions 52 take the form of columns, ridges, etc. Also in several embodiments, the surface feature portions 52 are provided recessed (i.e., set back) from the peripheral portion 54. Such surface feature portions 52 take the form of blind holes, grooves, or mesas extending from the peripheral portion 54 in the direction of the thickness 22 of the substrate 12 or the low refractive index material. In several embodiments, a portion of the surface feature portion 52 may be provided recessed from the peripheral portion 54, and a portion of the surface feature portion 52 may protrude from the peripheral portion 54. In several embodiments, the surface feature portion 52 is surrounded by a continuous peripheral portion 54 without breaks.

[0052] One or more high-level surfaces 26 located at the high-average altitude 28 are obtained by either the surface feature portion 52 or the peripheral portion 54, and one or more low-level surfaces 32 located at the low-average altitude 34 are obtained by the other of the surface feature portion 52 or the peripheral portion 54. When the surface feature portion 52 protrudes from the peripheral portion 54 (see Figure 3B), one or more high-level surfaces 26 located at the high-average altitude 28 are obtained by the surface feature portion 52. In this example, one or more low-level surfaces 32 located at the low-average altitude 34 are obtained by the peripheral portion 54. When the surface feature portion 52 is recessed from the peripheral portion 54 (see Figure 3A), one or more high-level surfaces 26 located at the high-average altitude 28 are obtained by the peripheral portion 54. In this example, one or more low-level surfaces 32 located at the low-average altitude 34 are obtained by the surface feature portion 52.

[0053] The high refractive index material 36 is provided on one or more low-level surfaces 32 located at the low mean height 34, between the surface feature portion 52 and the peripheral portion 54. In embodiments where the surface feature portion 52 is recessed from the peripheral portion 54, the high refractive index material 36 is provided on one or more low-level surfaces 32 located at the low mean height 34 formed by the surface feature portion 52. In embodiments where the surface feature portion 52 protrudes from the peripheral portion 54, the high refractive index material 36 is provided on one or more low-level surfaces 32 located at the low mean height 34 formed by the peripheral portion 54, between the surface feature portions 52. In embodiments where the high refractive index material 36 is located in the peripheral portion 54 and the peripheral portion 54 is continuous without breaks, the high refractive index material 36 can form a single continuous intermediate surface 38 around the surface feature portion 52 that protrudes through the high refractive index material 36 toward the external environment 24.

[0054] In several embodiments, one or more high-level surfaces 26 located at the high-level mean altitude 28 are planar. In several embodiments, one or more low-level surfaces 32 located at the low-level mean altitude 34 are planar. In other embodiments, one or more low-level surfaces 32 are convex or concave. In several embodiments, part of one or more low-level surfaces 32 can be concave and the others convex.

[0055] The texture region 20, comprising one or more high-level surfaces 26 located at a high-level average altitude 28 and one or more low-level surfaces 32 located at a low-level average altitude 34, is a diffraction structure generated in a way that controls the scattering of reflected ambient light. By scattering the reflected ambient light, specular reflectivity and image sharpness are reduced. Furthermore, as will be described in detail later, the high-refractive-index material 36, which has a refractive index higher than that of the substrate 12 (or the low-refractive-index material on the substrate 12), improves the transmission of light passing through the texture region 20 (such as light emitted from the display 16), thus reducing transmission haze and pixel power deviation compared to using only the texture region 20 without the high-refractive-index material 36.

[0056] In several embodiments, the surface feature portions 52 are arranged in a random distribution. In other words, in such embodiments, the surface feature portions 52 are not arranged in a pattern. However, in other embodiments, the surface feature portions 52 are arranged in a pattern such as a hexagon. If the surface feature portions 52 are arranged in a pattern, there is a risk that the texture area 20 will generate a moiré interference pattern due to the reflection of ambient light. Also, by not arranging the surface feature portions 52 in a pattern, the wavelength dependence of scattered ambient light can be reduced. Therefore, in some applications, it may be more advantageous not to arrange the surface feature portions 52 in a pattern.

[0057] Referring to Figure 4, the degree of hexagonality of the surface feature portion 52 is shown as an indicator of randomness. The degree of hexagonality is an indicator used to locally quantify how closely the arrangement of objects within a certain area approximates a hexagonal grid arrangement. Each object within the area has a center point. The degree of hexagonality H at each of these center points within the area is calculated using the following formula, with respect to an arbitrary axis the angles of the six points closest to that center point.

[0058]

number

[0059] Variable αk H=1 represents the angles of the six closest points. In a hexagonal grid, the difference between these six angles is 60 degrees (π / 3 radians), so the difference between the exponents of the six addends is 2π radians, and all six complex numbers in this sum are equal. In this case, H=1, which is a regular hexagonal grid. Each center point within an area has a unique H value. The average of all H values ​​within an area represents the degree of deviation from the hexagonal grid arrangement. The further the average of all H values ​​is from 1, the more random the arrangement is.

[0060] Each surface feature portion 52 has an outer circumference 56 parallel to the reference plane 30. In several embodiments, the outer circumference 56 of each surface feature portion 52 has the same shape. For example, in several embodiments such as the embodiment shown in Figure 2, the outer circumference 56 of each surface feature portion 52 is circular. In several embodiments, the outer circumference 56 of each surface feature portion 52 is elliptical. In several embodiments, the outer circumference 56 of each surface feature portion 52 is hexagonal or polygonal. In several embodiments, the outer circumference 56 of the surface feature portion 52 is one of two or more shapes (for example, partly elliptical and partly circular).

[0061] The outer circumference 56 of each surface feature portion 52 has a longest dimension 58. If the outer circumference 56 is circular, the longest dimension 58 is the diameter of the outer circumference 56. If the outer circumference 56 is hexagonal, the longest dimension 58 is the major axis (long diagonal). The same applies to other cases. In several embodiments, the longest dimension 58 of the outer circumference 56 of each surface feature portion 52 is 5 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 170 μm, 180 μm, 190 μm, or 200 μm, or any range with any two of these values ​​as upper and lower limits (for example, 5 μm to 200 μm, 20 μm to 100 μm, 80 μm to 120 μm, 30 μm to 70 μm, 25 μm to 75 μm, etc.).

[0062] In several embodiments, the surface feature portions 52 are spaced at least by a minimum center-to-center distance 60. For example, if the minimum center-to-center distance 60 is 100 μm, the distance from the center of one surface feature portion 52 to the center of an adjacent surface feature portion 52 may be 100 μm or more, but will never be less than 100 μm. In several embodiments, the minimum center-to-center distance 60 is 5 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, or 130 μm, or any range with any two of these values ​​as upper and lower limits (e.g., 30 μm to 70 μm, 40 μm to 80 μm, 5 μm to 100 μm, 20 μm to 90 μm, 30 μm to 80 μm, etc.).

[0063] The high refractive index material 36, which has a refractive index higher than that of the substrate 12 (or the low refractive index material on the substrate 12), reduces the pixel power deviation generated by the texture region 20. Therefore, it is possible to increase the minimum center-to-center distance 60 compared to when the high refractive index material 36 is not incorporated. Furthermore, by incorporating the high refractive index material 36, it is possible to increase the maximum dimension 58 of the surface feature portion 52 compared to when the high refractive index material 36 is not incorporated. This is beneficial for several reasons. Firstly, the longer the maximum dimension 58 of the surface feature portion 52, the easier it is to manufacture the surface feature portion 52, and consequently the texture region 20. Therefore, by incorporating the high refractive index material 36, it is possible to manufacture the texture region 20 using low-cost methods such as inkjet printing, screen printing, and gravure offset printing. Secondly, the longer the maximum dimension 58 of the outer circumference 56 of the surface feature portion 52, the lower the transmission haze generated from the texture region 20. However, there are practical limitations on the maximum dimension 58 of the surface feature portion 52. This is because, when the longest dimension 58 becomes long enough, the surface feature portion 52 becomes visible to the human eye, which may be undesirable.

[0064] Thirdly, when the longest dimension 58 of the outer circumference 56 of the surface feature portion 52 is sufficiently long, the scattering intensity of reflected light increases in a narrow angular range including an angle of about 0.3 degrees from the specular reflection angle. As a result, the pixel power deviation occurring in the texture region 20 increases. Furthermore, since this scattering of reflected light does not extend over an angular range wide enough for the human eye to distinguish colors, reflected color artifacts are reduced. For example, the angular difference between the peak scattering angle of light in the 450 nm wavelength portion and the peak scattering angle of light in the 650 nm wavelength portion can be less than 0.4 degrees, less than 0.3 degrees, or even less than 0.2 degrees. It is preferable that the difference in scattering angles between different wavelengths be small. This is because it is difficult for the human eye to resolve extremely small differences in scattering angles, so when the difference in scattering angles between wavelengths is small, the viewer does not see much of the color of the scattered light.

[0065] In several embodiments, the substrate 12 comprises glass or glass ceramic. In several embodiments, the substrate 12 is a multi-component glass composition comprising about 40 mol% to 80 mol% silica in a balanced manner with one or more other components (e.g., alumina, calcium oxide, sodium oxide, boron oxide, etc.). In some embodiments, the bulk composition of the substrate 12 is selected from the group consisting of aluminosilicate glass, borosilicate glass, and phosphate silicate glass. In other embodiments, the bulk composition of the substrate 12 is selected from the group consisting of aluminosilicate glass, borosilicate glass, phosphate silicate glass, soda-lime glass, alkali aluminosilicate glass, and alkali aluminoborosilicate glass. In further embodiments, the substrate 12 is a glass-based substrate and includes, but is not limited to, a glass ceramic material containing about 90% by mass or more of glass components and ceramic components. In other embodiments of the display article 10, the substrate 12 can be a polymer material having durability and mechanical properties suitable for growing and retaining the texture area 20. In other embodiments, the substrate 12 is a single-crystal structure such as sapphire, or includes a single-crystal structure.

[0066] In several embodiments, the bulk composition of the substrate 12 includes an alkali aluminosilicate glass containing alumina, at least one alkali metal, and SiO2. In some embodiments, this glass contains more than 50 mol% SiO2, in other embodiments, at least 58 mol% SiO2, and in yet another embodiment, at least 60 mol% SiO2, with a ratio of (Al2O3 (mol%) + B2O3 (mol%)) / Σ alkali metal modifier (mol%) > 1, where the alkali metal modifier is an alkali metal oxide. In certain embodiments, the glass contains (or essentially consists of) about 58 mol% to about 72 mol% of SiO2, about 9 mol% to about 17 mol% of Al2O3, about 2 mol% to about 12 mol% of B2O3, about 8 mol% to about 16 mol% of Na2O, and 0 mol% to about 4 mol% of K2O, with a ratio of (Al2O3 (mol%) + B2O3 (mol%)) / Σ alkali metal modifier (mol%) > 1, where the alkali metal modifier is an alkali metal oxide.

[0067] In several embodiments, the bulk composition of the substrate 12 includes an alkali aluminosilicate glass containing (or essentially consisting of, or comprising) about 61 mol% to about 75 mol% of SiO2, about 7 mol% to about 15 mol% of Al2O3, 0 mol% to about 12 mol% of B2O3, about 9 mol% to about 21 mol% of Na2O, 0 mol% to about 4 mol% of K2O, 0 mol% to about 7 mol% of MgO, and 0 mol% to about 3 mol% of CaO.

[0068] In several embodiments, the bulk composition of the substrate 12 is approximately 60 mol% to approximately 70 mol% of SiO2, approximately 6 mol% to approximately 14 mol% of Al2O3, 0 mol% to approximately 15 mol% of B2O3, 0 mol% to approximately 15 mol% of Li2O, 0 mol% to approximately 20 mol% of Na2O, 0 mol% to approximately 10 mol% of K2O, 0 mol% to approximately 8 mol% of MgO, 0 mol% to approximately 10 mol% of CaO, and approximately 0 mol% to approximately The material contains alkali aluminosilicate glass containing (or essentially consisting of) 5 mol% ZrO2, 0 mol% to about 1 mol% SnO2, 0 mol% to about 1 mol% CeO2, less than about 50 ppm As2O3, and less than about 50 ppm Sb2O3, with 12 mol% ≤ Li2O + Na2O + K2O ≤ 20 mol%, and 0 mol% ≤ MgO + Ca ≤ 10 mol%.

[0069] In several embodiments, the bulk composition of the substrate 12 includes (or essentially consists of, or comprises) about 64 mol% to about 68 mol% of SiO2, about 12 mol% to about 16 mol% of Na2O, about 8 mol% to about 12 mol% of Al2O3, 0 mol% to about 3 mol% of B2O3, about 2 mol% to about 5 mol% of K2O, about 4 mol% to about 6 mol% of MgO, and 0 mol% to about 5 mol% of CaO, 66 This product contains alkali aluminosilicate glass with the following characteristics: mol% ≤ SiO2 + B2O3 + CaO ≤ 69 mol%, Na2O + K2O + B2O3 + MgO + CaO + SrO > 10 mol%, 5 mol% ≤ MgO + CaO + SrO ≤ 8 mol%, (Na2O + B2O3)-Al2O3 ≤ 2 mol%, 2 mol% ≤ Na2O-Al2O3 ≤ 6 mol%, and 4 mol% ≤ (Na2O + K2O)-Al2O3 ≤ 10 mol%.

[0070] In several embodiments, the bulk composition of the substrate 12 includes SiO2, Al2O3, P2O5, and at least one alkali metal oxide (R2O), where 0.75 > [(P2O5 (mol%) + R2O (mol%)) / M2O3 (mol%)] ≤ 1.2, and M2O3 = Al2O3 + B2O3. In several embodiments, [(P2O 5( %) + R2O (mol%) / M2O 3([mol%] = 1, and in several embodiments, the glass does not contain B2O3 and M2O3 = Al2O3. In several embodiments, the substrate 12 contains about 40 to about 70 mol% SiO2, 0 to about 28 mol% B2O3, about 0 to about 28 mol% Al2O3, about 1 to about 14 mol% P2O5, and about 12 to about 16 mol% R2O. In some embodiments, the glass substrate contains about 40 to about 64 mol% SiO2, 0 to about 8 mol% B2O3, about 16 to about 28 mol% Al2O3, about 2 to about 12 mol% P2O5, and about 12 to about 16 mol% R2O. The substrate 12 may also further contain at least one alkaline earth metal oxide. Examples of alkaline earth metal oxides include, but are not limited to, MgO or CaO.

[0071] In some embodiments, the substrate 12 has a substantially lithium-free bulk composition. That is, the amount of Li2O contained in the glass is less than 1 mol%, in other embodiments it is less than 0.1 mol%, in other embodiments it is 0.01 mol%, and in yet other embodiments it is 0 mol%. In some embodiments, such glass does not contain at least one of arsenic, antimony, and barium. That is, the amount of As2O3, Sb2O3, and / or BaO contained in the glass is less than 1 mol%, in other embodiments it is less than 0.1 mol%, and in yet other embodiments it is 0 mol%.

[0072] In several embodiments, the bulk composition of the substrate 12 includes (or essentially consists of) Corning® Eagle XG® glass, Corning® Gorilla® glass, Corning® Gorilla® glass 2, Corning® Gorilla® glass 3, Corning® Gorilla® glass 4, or Corning® Gorilla® glass 5.

[0073] In several embodiments, the substrate 12 has an ion-exchangeable glass composition strengthened by either chemical or thermal means known in the art. In several embodiments, the substrate 12 is chemically strengthened by ion exchange. In this process, metal ions on or near the main surface 18 of the substrate 12 are exchanged for larger metal ions in the substrate 12 with the same valence. Generally, ion exchange is performed by bringing the substrate 12 into contact with an ion exchange medium (e.g., a molten salt bath) containing larger metal ions. These metal ions are usually monovalent metal ions, such as alkali metal ions. For example, when chemically strengthening a substrate 12 containing sodium ions by ion exchange, the strengthening of the substrate 12 is performed by immersing the substrate 12 in an ion exchange bath containing a molten potassium salt such as potassium nitrate (KNO3). In certain embodiments, ions in the surface layer adjacent to the main surface 18 of the substrate 12, and larger ions, are Li + (When located inside glass), or Na + , K + , Rb + , Cs + These are monovalent alkali metal cations such as Ag. Alternatively, monovalent cations in the surface layer of the substrate 12 are Ag + It is also possible to substitute with monovalent cations other than alkali metal cations, such as those mentioned above.

[0074] In such embodiments, a compressive stress region is formed within the substrate 12 by replacing smaller metal ions with larger metal ions in an ion exchange process, extending to a depth (referred to as the "depth of layer") from the main surface 18. This compressive stress in the substrate 12 balances the tensile stress (also known as "central tension") within the substrate 12. In some embodiments, the main surface 18 of the substrate 12 described herein, having been strengthened by ion exchange, has a compressive stress of at least 350 MPa, and the compressive stress region extends to a depth (i.e., the depth of layer) of at least 15 μm within the thickness 22 below the main surface 18.

[0075] The ion exchange process is typically carried out by immersing the substrate 12 in a molten salt bath containing larger ions that will replace smaller ions in the glass. Parameters of the ion exchange process include, but are not limited to, the composition and temperature of the bath, the immersion time, the number of times the glass is immersed in (one or more) salt baths, the use of multiple salt baths, and additional steps such as annealing or washing. Those skilled in the art will understand that the parameters of such an ion exchange process are typically determined by the composition of the glass, as well as the desired glass layer depth and compressive stress as a result of the strengthening treatment. For example, ion exchange of alkali metal-containing glass can be carried out by immersion in at least one molten bath containing salts of large alkali metal ions (e.g., nitrates, sulfates, chlorides, etc., but not limited to these). The temperature of the molten salt bath is typically in the range of about 380°C to about 450°C, and the immersion time is typically in the range of about 15 minutes to about 16 hours. However, different temperatures and immersion times may be used. When such ion exchange treatment is performed on a substrate 12 having an alkali aluminosilicate glass composition, a compressive stress region is obtained with a depth (layer depth) in the range of approximately 10 μm to at least 50 μm, a compressive stress in the range of approximately 200 MPa to approximately 800 MPa, and a central tension of less than approximately 100 MPa.

[0076] Although the texture region 20 of the substrate 12 can be formed using an etching process, the etching process may remove alkali metal ions in the substrate 12 that were supposed to be replaced by large alkali metal ions during the ion exchange process. For this reason, it is preferable to form and grow the texture region 20 first, and then grow the compressive stress region on the display item 10.

[0077] In several embodiments, the texture region 20 represents the pixel power deviation ("PPD"). Details of the measurement system and image processing calculations used to obtain the PPD value are described in U.S. Patent No. 9,411,180 (title of the invention, "Apparatus and Method for Determining Sparkle"). All portions of this patent specification, particularly those relating to PPD measurement, are incorporated herein by reference. Furthermore, unless otherwise noted, the generation and evaluation of PPD measurements in this disclosure were performed using the SMS-1000 system (Display-Messtechnik & Systeme GmbH & Co. KG). The PPD measurement system comprises a pixelation source and an imaging system. The pixelation source (e.g., a 140ppi Lenovo Z50 notebook computer) comprises a plurality of pixels, each of which has reference indices i and j. The imaging system is optically positioned along the optical path emitted by the pixelation source. The imaging system comprises an imaging device and a diaphragm. The imaging device is positioned along the optical path and has a pixelated sensing area comprising a second set of pixels, each of which is referenced by indices m and n. The diaphragm is positioned in the optical path between the pixelation source and the imaging device and has an adjustable focusing angle with respect to the image emitted by the pixelation source. The image processing calculation includes the steps of: acquiring a pixelated image of a transparent sample comprising a set of pixels; identifying the boundaries between adjacent pixels in the pixelated image; determining the integral energy of each original pixel in the pixelated image by performing integration within the boundaries; and determining the standard deviation of the integral energy of each original pixel, with the obtained standard deviation being the power deviation per pixel. In this specification, all calculations and evaluations of the PPD value, characteristics, and upper and lower limits have been performed using an experimental configuration with a display device having a pixel density of 140 pixels per inch (approximately 25.4 mm) (140 PPI).In several embodiments, the display article 10 exhibits a PPD of 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, or any range (e.g., 1.2% to 2.1%) with any two of these values ​​as upper and lower limits. In several embodiments, the textured area 20 exhibits a PPD of less than 4%, less than 3%, less than 2.5%, less than 2.1%, less than 2.0%, or less than 1.75%, and even less than 1.5%.

[0078] Furthermore, because the pixel power deviation value generated by the texture area 20 of this disclosure is so low, the display 16 of the display article 10 can have a higher resolution than usual. As mentioned in the previous paragraph, the pixel power deviation value is measured using a display with a resolution of 140 pixels per inch (approximately 25.4 mm) (140 ppi), which is an industry standard. The texture area 20 of this disclosure can transmit such a resolution while suppressing the pixel power deviation. Therefore, it is possible to increase the resolution of the display 16. In several embodiments, the display 16 of the display article 10 has a resolution greater than 140 ppi, for example, a resolution in the range of 140 ppi to 300 ppi.

[0079] In several embodiments, the texture region 20 indicates the image sharpness ("DOI"). In this specification, the specular reflection flux measured by light incident on the texture region 20 (at an angle of 20° from the normal) is R S , the specular reflection flux R measured with the same incident light S The reflected flux in the direction of 0.3° from R 0.3゜ Therefore, "DOI" is 100*(R S -R 0.3゜ ) / R SAs shown above. Unless otherwise specified, the DOI values ​​and measurements described herein were obtained in accordance with ASTM standard D5767-18, "Standard Test Method for Instrumental Measurement of Distinctness-of-Image (DOI) Gloss of Coated Surfaces using a Rhopoint IQ Gloss Haze & DOI Meter." Furthermore, the DOI measurements were performed with the back surface of the substrate 12 (the surface opposite to the main surface 18) coupled to the absorber to eliminate reflection from the back surface. Therefore, the DOI values ​​described herein are "coupled" values, i.e., "first surface" values. In several embodiments, the image clarity ("DOI") of the texture region 20 is 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, or 85%, or any range with any two of these values ​​as upper and lower limits (e.g., 25% to 85%). In several embodiments, the image clarity of the texture region 20 is less than 90%, less than 80%, less than 70%, less than 60%, less than 50%, less than 40%, or less than 35%, and even less than 30%.

[0080] In several embodiments, the texture region 20 exhibits transmission haze. In this specification, the term "transmission haze" refers to the proportion of transmitted light scattered outside an angular cone of approximately ±2.5°, according to ASTM standard D1003, "Standard Test Method for Haze and Luminous Transmittance of Transparent Plastics." All content described herein constitutes part of this specification by reference. In the examples, transmission haze was measured using a BYK Gardner Haze-Gard Plus with an integrating sphere detection system, using incident light with perpendicular incidence (0 degrees). Although ASTM standard D1003 is named after plastics, this standard also applies to substrates containing glass materials. Typically, the transmission haze of an optically smooth surface is close to zero. In several embodiments, the texture region 20 exhibits transparency haze of 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, 2.3%, 2.4%, or 2.5%, or any range (e.g., 1.5% to 2.5%) with any two of these values ​​as upper and lower limits. In several embodiments, the texture region 20 exhibits transparency haze of less than 20%, less than 10%, less than 5%, less than 3%, less than 2.5%, or less than 2.0%.

[0081] In several embodiments, the texture region 20 exhibits a specular reflectance of 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.75%, or any range (e.g., 0.5% to 1.75%) with any two of these values ​​as upper and lower limits. Specular reflectance measurements in this specification were performed using a gloss, haze, and DOI meter Rhopoint IQ (Rhopoint Instruments) at a reflection incidence angle of 20 degrees, with the back surface of the substrate 12 coupled to an absorber to eliminate back surface reflectance. The indicated value of this instrument (unit: GU (gloss unit)) is a normalized value based on a control sample of black glass with a refractive index of 1.567 and a known principal surface reflectance of 4.91% at an incident angle of 20 degrees, with the control sample value of 100 GU as the reference value. Therefore, the specular reflectance value in this specification is the value obtained by converting the instrument's generated value to the absolute specular reflectance (%) of the first surface according to the formula of multiplying the instrument's generated value by 0.0491.

[0082] In several embodiments, over an optical wavelength range of approximately 400 nm to approximately 800 nm, the textured region 20 exhibits transmittances of 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, or 95%, or any range with any two of these values ​​as upper and lower limits (e.g., 85% to 95%, 90% to 92%). In this specification, the term "transmittance" is defined as the percentage of optical power that passes through the substrate 12 and exits the textured region 20 when incident light of a wavelength within a given wavelength range is transmitted. Transmittances in the embodiments were measured using a BYK Gardner HazeGuard Plus with an integrating sphere detection system, with incident light at a perpendicular incidence (0 degrees). The transmittances described herein are total transmittances at all output angles.

[0083] In several embodiments, the texture region 20 simultaneously exhibits (i) a pixel power deviation in the range of 1.2% to 2.1%, (ii) a transmission haze in the range of 1.5% to 2.5%, (iii) a specular reflectance of 0.5% to 1.75%, and (iv) an image sharpness of 25% to 85%.

[0084] Referring here to Figure 5, a method 100 for forming a textured region 20 is described. Method 100 includes step 102 of forming surface feature portions 52 on the main surface 18 of the substrate 12 that protrude from or are recessed from the periphery, according to a predetermined positioning of each surface feature portion 52. Method 100 further includes step 104 of depositing a high refractive index material 36 onto either the surface feature portion 52 or the periphery 54 to provide one or more lower surfaces 32 located at the lower mean height 34. Steps 102 and 104 will be described further later.

[0085] In several embodiments, method 100 further includes a step 106 in which the positioning of each surface feature portion 52 is determined using a spacing distribution algorithm. As a result, the predetermined positioning of each surface feature portion 52 is achieved. This step 106 is performed before step 102 in which the surface feature portions 52 are formed on the substrate 12. Examples of spacing distribution algorithms include the Poisson disk sampling algorithm, the maxi-min spacing algorithm, and the hard-sphere distribution algorithm. In the spacing distribution algorithm, objects 108 are placed on the area 110 according to the minimum center-to-center distance 112 that separates the objects 108 (which represent the surface feature portions 52 or are the source of the arrangement of the surface feature portions 52). The minimum center-to-center distance 112 can be made to match the minimum center-to-center distance 60 of the desired surface feature portions 52.

[0086] According to the Poisson disk sampling algorithm, a first object 108 (a circular object with a diameter matching the desired longest dimension 58 for the surface feature portion 52) is inserted into area 48. Next, the algorithm inserts a second object 108 into area 48, placing its center at a random position within area 48. If the placement of the second object 108 satisfies the minimum center-to-center distance 112 from the first object 108, the second object 108 remains in area 48. The algorithm then repeats this process until it is no longer possible to place an object 108 that satisfies the minimum center-to-center distance 112 within area 110. This results in the objects 108 being placed at specific locations in a random distribution.

[0087] The maximin spacing algorithm, as its name suggests, attempts to maximize the minimum nearest-center distance 112 of a point distribution (i.e., in this algorithm, objects in an area are points). This algorithm proceeds by repeatedly moving each object 108 to another location further away from any adjacent object than it is currently located, and therefore does not typically generate a regular hexagonal grid arrangement. The maximin spacing algorithm generates a random distribution with a relatively high mean hexagonality (often exceeding 90%).

[0088] The rigid sphere distribution algorithm is a molecular dynamics simulation performed at a finite temperature. Specifically, it is used in the molecular dynamics simulator LAMMPS (URL: https: / / www.lammps.org / , last accessed: June 26, 2021). According to this algorithm, objects 108 are placed in area 110 in a random distribution, and at specific positions that are not part of a hexagonal grid. However, this algorithm also results in a higher degree of hexagonality in the resulting arrangement compared to the Poisson disk algorithm.

[0089] In either case, the positioning of the object 108 in area 110 determines the predetermined positioning of each surface feature portion 52 to be formed on the substrate 12 in a subsequent process, or the predetermined position of each surface feature portion 52 is derived from the positioning of the object 108 in area 110.

[0090] In several embodiments, method 100 further includes step 114 of placing an etching mask 116 on the main surface 18 of the substrate 12. Then, a subsequent step 102 of forming the surface feature portion 52 includes bringing the substrate 12 into contact with an etching solution 118 with the etching mask 116 placed on the main surface 18 of the substrate 12.

[0091] In several embodiments, the etching mask 116 is formed on the substrate 12 as a positive or negative mask of the area 110 where the objects 108 are arranged according to a spacing distribution algorithm. In other words, in several embodiments, the etching mask 116 is formed to match the arrangement of the objects 108 on the main surface 18 of the substrate 12, in which case the etching mask 116 prevents subsequent etching at locations where the surface feature portion 52 is formed according to a predetermined position of the surface feature portion 52. In such an example, the etching step 102 yields a surface feature portion 52 that protrudes from the peripheral portion 54. In other embodiments (such as the embodiment shown in Figure 5), the etching mask 116 is formed as a negative mask of the arrangement of the objects 108 on the area 110, preventing etching at locations that will become the peripheral portion 54 and allowing etching only at locations that will become the surface feature portion 52 (i.e., locations in the area where the objects are arranged).

[0092] In several embodiments, the etching solution 118 contains one or more of hydrofluoric acid and nitric acid. In several embodiments, the etching solution 118 contains both hydrofluoric acid and nitric acid. The etching solution 118 can be sprayed onto the substrate 12 with the etching mask 116 placed on the substrate 12. Alternatively, the substrate 12 with the etching mask 116 attached can be immersed in a tank 120 containing the etching solution 118. In several embodiments, the contact time of the etching solution 118 with the substrate 12 is 10 seconds, 20 seconds, 30 seconds, 40 seconds, 50 seconds, or 60 seconds, or any range with any two of these values ​​as upper and lower limits (e.g., 10 seconds to 60 seconds). After this contact time, the substrate 12 is rinsed with deionized water and dried. The longer the etching solution 118 is in contact with the substrate 12, the deeper the etching of the substrate 12 by the etching solution 118 becomes. As a result, the distance 42 between one or more high surfaces 26 of the substrate 12 located at the high average height 28 and one or more low surfaces 32 of the substrate 12 located at the low average height 34 becomes larger.

[0093] As described above, method 100 includes step 104 of depositing the high refractive index material 36 on either the surface feature portion 52 or the peripheral portion 54. In some embodiments, the deposition of the high refractive index material 36 is performed after the surface feature portion 52 is formed in step 102, while the etching mask 116 remains in place on the substrate 12. By depositing the high refractive index material 36 while the etching mask 116 remains on the substrate 12, it is possible to reliably deposit the high refractive index material 36 only in the desired locations. For example, regardless of whether one or more low-lying surfaces 32 of the substrate 12 located at the low mean height 34 are obtained by the surface feature portion 52 or the peripheral portion 54, it is possible to deposit the high refractive index material 36 only on the one or more low-lying surfaces 32, and not on the one or more high-lying surfaces 26 located at the high mean height 28. Various deposition methods can be used to deposit the high refractive index material 36, such as chemical vapor deposition (e.g., plasma chemical vapor deposition, low-pressure chemical vapor deposition, atmospheric pressure chemical vapor deposition, and atmospheric pressure plasma chemical vapor deposition), physical vapor deposition (e.g., reactive or non-reactive sputtering or laser ablation), thermal deposition or electron beam deposition, and / or vacuum deposition techniques such as atomic layer deposition. In some embodiments, the high refractive index material 36 is deposited by reactive sputtering.

[0094] In several embodiments, method 100 further includes step 122 to remove the etching mask 116 after depositing the high refractive index material 36 in step 104. Depending on the composition of the etching mask 116, the etching mask 116 can be removed from the substrate 12 using an organic solvent such as acetone or isopropyl alcohol.

[0095] In a modified example, a film of low refractive index material is deposited on the main surface 18 of the substrate 12 before step 114. Then, an etching mask 116 is placed on the substrate 12 so as to cover the low refractive index material. Next, in step 102, with the etching mask 116 placed on the low refractive index material, the low refractive index material is brought into contact with the etching solution 118 to form the surface feature portion 52. From this point onward, the remainder of method 100 is carried out as described above. [Examples]

[0096] Comparative Example 1A As Comparative Example 1A, an embodiment of the texture region of this disclosure was modeled as a diffraction grating using a commercially available software package, Gsolver (Grating Solver Development Company, Saratoga Springs, Utah, USA). The modeled substrate is one in which the peripheral area forms a surface with a high mean height, and the linear grooves (as surface features) that are recessed from the peripheral area form a surface with a lower mean height than the high mean height. The intercenter spacing (gratting period) of the linear grooves was set to 20 μm. In the model, the ambient light was assumed to be light of a single wavelength of 550 nm. The substrate was made of glass with a refractive index of 1.518. A high refractive index material (especially SiO2) with a high refractive index of 1.892 was placed on the linear groove surface located at the lower mean height. x N yA layer of high refractive index material was added with a filling density of 50%. As a result, all surfaces formed by the high refractive index material became surfaces at the median mean height between the high mean height and low mean height of the substrate. The air trench depth (the distance between the high mean height of the substrate and the median mean height of the high refractive index material deposited in the linear groove) was set to 220 nm. The trench depth (the distance between the high mean height and low mean height of the substrate) was varied from approximately 220 nm to over 700 nm, and the height of the high refractive index material deposited in the groove was adjusted as appropriate to maintain the air trench depth at 220 nm. Next, the 0th to 5th order diffraction efficiency was calculated as a function of the trench depth (and therefore also as a function of the height of the high refractive index material added to maintain an air trench depth of 220 nm) for both the light transmitted through the modeled texture region (Figure 6A) and the light reflected from the modeled texture region (Figure 6B). Figure 6A shows a reproduction of the modeling results for transmitted light, and Figure 6B shows a reproduction of the modeling results for reflected light.

[0097] From the modeling results reproduced in Figure 6A, it can be seen that in order to maximize the transmittance that passes through the substrate and exits the textured area, the trench depth of the substrate needs to be 520 nm (0.52 μm). Therefore, in order to maintain the air trench depth at 220 nm, the high refractive index material SiO2 must be added to the linear groove. x N y The height needs to be 300 nm. However, as the modeling results reproduced in Figure 6B show, if the trench depth of the substrate is 520 nm, the specular reflectance (0th order corresponds to the specular surface) cannot be sufficiently minimized.

[0098] Example 1B Example 1B is a modeling example similar to Comparative Example 1A. However, Example 1B differs from Comparative Example 1A in that the air trench depth is fixed and the trench depth of the substrate is not varied. Instead, in Example 1B, the trench depth of the substrate is set to: high refractive index material SiO x N yThe ratio of height to air trench depth was fixed at 3:1.6:1.4. In this model, diffraction efficiency was determined as a function of the trench depth of the substrate for both transmitted light (Figure 7A) and reflected light (Figure 7B). Other parameters of the model in Example 1B were set for the high refractive index material SiO x N y The packing rate, including 50%, was the same as in Comparative Example 1A.

[0099] The graph in Figure 7A shows that the zero-order (specular, not diffractive) transmittance, which passes through the substrate and exits the textured area, remains high regardless of the trench depth of the substrate. On the other hand, the diffractive transmittance (first order and above) is very close to zero. This is because the above ratio of 3:1.6:1.4 is almost an ideal ratio for a transparent diffusing material. The graph in Figure 7B shows that when the trench depth of the substrate is changed, the specular reflectance (zero order) and scattered reflectance (first order and above) change significantly. Specular reflectance peaks at trench depths of approximately 0.10 μm and 0.50 μm, so substrates with these trench depths are undesirable. On the other hand, when the trench depth of the substrate is 0.22 μm to 0.37 μm, the specular reflectance is minimized. Furthermore, the first-order diffractive reflectance is minimized at approximately 0.30 μm. If the above ratio is adopted, and the trench depth of the substrate is 0.22 μm to 0.37 μm, the high refractive index material SiO x N y The height is 0.12 μm to 0.20 μm, and the air trench depth is 0.10 μm to 0.20 μm. Therefore, the target values ​​using this model are, for example, a substrate trench depth of 0.32 μm and a high refractive index material SiO2 provided recessed from the surface feature area. x N y The height is 0.17 μm and the air trench depth is 0.15 μm. Furthermore, this model demonstrates that by appropriately designing the textured region disclosed herein, the specular reflectivity can be suppressed by 5 times, or even 10 times or more, compared to flat glass without texture.

[0100] Referring to Figures 7C and 7D, the model is used to examine both transmission (Figure 7C) and reflection (Figure 7D) of the high refractive index material SiOx N y The diffraction efficiency was calculated as a function of the packing ratio (the ratio obtained by subtracting the packing ratio of the low refractive index substrate from 100%). In this model, the trench depth of the substrate was 0.32 μm, and the high refractive index material SiO was provided recessed from the surface feature area. x N y The height was assumed to be 0.17 μm and the air trench depth 0.15 μm. In this model as well, the center-to-center distance was assumed to be 20 μm and the wavelength 550 nm. From the graph in Figure 7C, it can be seen that according to this model, the specular transmittance is high and the transmission scattering rate is low for all the packing density considered. This is due to the trench depth of the substrate and the high refractive index material SiO, which is recessed from the surface feature area. x N y This is because the ratio of the height and air trench depth had already been optimized according to the transparent diffuser standard. From the graph in Figure 7D, it can be seen that this model minimizes specular reflection (0th order) when the substrate (low refractive index) filling density is in the range of 52% to 62%. This is because the high refractive index material SiO x N y This corresponds to setting the filling density to a range of 38% to 48%. Depending on the application, the goal of the optimal design may not only be to suppress specular reflection (0th order), but also to simultaneously achieve minimization of specular reflection intensity and one or more higher-order (1st, 2nd, etc.) diffraction reflection intensity. In applications where minimizing diffraction reflection intensity at all diffraction orders is desired, the filling density of the low refractive index substrate or low refractive index material can be set to approximately 75%, or about 55% to about 78%. This is because high refractive index materials (e.g., SiO₂) x N y This corresponds to a filling rate of 25%, or approximately 22% to 45%.

[0101] Referring now to Figures 7E and 7F, the high refractive index material SiO x N y The substrate has a packing density of 45%, a trench depth of 0.32 μm, and is made of high refractive index material SiO2. x N yModeling was performed with optimal parameters of a height of 0.17 μm and an air trench depth of 0.15 μm, and the reflectance (Figure 7E) and transmittance (Figure 7F) were calculated as functions of the incident light angle for the obtained model. As can be seen from the graph in Figure 7E, the specular reflectance (first surface) of the modeled texture region is less than 1% for any incident light angle from 0 to approximately 40 degrees. Also, as can be seen from the graph in Figure 7F, the modeled texture region transmits more than 90% of the incident light for any incident light angle from 0 to approximately 40 degrees.

[0102] Examples 2A-2G In Examples 2A to 2G, the rigid sphere spacing distribution algorithm (LAMMPS) was used to determine the positioning of each surface feature to be placed on the main surface 18 of the substrate. The rigid sphere spacing distribution algorithm aimed to place objects (circles) in an area until 50% of that area was occupied by objects. This goal can also be rephrased as depositing high refractive index material on the substrate until the filling rate reached 50%. The diameter of the object circles was set to 50 μm, and the minimum center-to-center spacing was set to 60 μm. Specifically, using software, a gas of "molecules" representing objects (i.e., desired surface feature areas) was initially placed on a two-dimensional hexagonal grid with a fixed filling rate of 50%. Subsequently, the gas was heated to perform two-dimensional randomization. A repulsive rigid sphere potential was applied to the molecules to maintain a minimum center-to-center spacing of 60 μm. As a result, the objects within the area were arranged as shown in the graph in Figure 2. The average hexagonalness of the obtained object placement was 0.49, which indicates a significant deviation from a hexagonal grid, and consequently, that the objects are placed in specific locations despite having a high degree of randomness. The graph reproduced in Figure 8 is a histogram showing the ratio of all objects placed within the area as a function of the center-to-center distance to the nearest object.

[0103] Next, etching masks were formed on seven glass substrate samples so as to superimpose object placements according to the rigid sphere spacing distribution algorithm. Each sample's etching mask was configured to allow etching of the substrate in areas where objects were placed according to the rigid sphere spacing distribution algorithm, while preventing etching of the substrate in areas where no objects were placed. Subsequently, all seven substrate samples with the etching masks attached were brought into contact with the etching solution. By varying the contact time for each sample, it was possible to generate surface features with different trench depths. The etching solution formed surface features across the entire texture area, where objects were placed according to the algorithm, resulting in a shape that was recessed from the surrounding areas. Two of these samples were then separated into Examples 2F and 2G as comparative examples.

[0104] After etching, the etching masks were left attached to the substrate samples of Examples 2A to 2E. Then, a high refractive index material, specifically AlN, with a refractive index higher than the substrate's refractive index (~1.51), was deposited on the surface of each surface feature. In some samples, the deposition time was varied, resulting in differences in the height of the deposited high refractive index material. Subsequently, the etching masks were removed from each substrate sample. Due to the effects of the manufacturing process and slight shadows created during deposition, the filling density of the high refractive index material AlN ranged from 40% to 49%.

[0105] Next, all samples from Examples 2A to 2G were subjected to various optical measurements. Specifically, pixel power deviation ("PPD"), transmittance, transmitted haze ("haze"), image clarity ("DOI"), and specular reflectance were measured. Table 1 below shows the measurement results for each sample, along with the air trench depth and the height of the high refractive index material AlN deposited in each surface feature area ("AlN height"). Examples 2F and 2G are comparative examples, and since high refractive index material AlN was not deposited in the surface feature area, the "air trench depth" values ​​for Examples 2F and 2G indicate the height difference between the substrate in the surface feature area and the substrate in the surrounding area. Figure 2 is a reproduction of a scan of Example 2C, after the high refractive index material AlN was placed in the surface feature area, using an optical profilometer.

[0106] [Table 1]

[0107] Analysis of the data presented in Table 1 revealed that in Examples 2A to 2E, incorporating a high refractive index material into the surface feature area significantly reduced the pixel power deviation compared to both Examples 2F and 2G, without significantly adversely affecting other optical property measurements. In particular, Examples 2B and 2C exhibited a combination of measurement values ​​that demonstrated favorable optical properties, specifically a pixel power deviation of less than 1.5%, transmittance of over 92%, transmission haze of less than 2%, image sharpness of less than 50%, and specular reflectance of less than 0.85%. Such a combination of values ​​would be difficult or impossible to achieve by other methods. This was especially difficult to achieve in surface feature areas with a maximum dimension of approximately 50 μm, which is easier to manufacture than those with a maximum dimension smaller than approximately 50 μm.

[0108] Examples 3A-3D In Examples 3A-3D, a spacing distribution algorithm implementing the Poisson disk sampling method was used to determine the positioning of each surface feature area to be placed on the main surface of the substrate. This algorithm aimed to place objects (circles) in an area until 36% of that area was occupied by objects. This goal can also be rephrased as depositing high refractive index material within the surface feature area until the filling rate reached 36%. The diameter of the object circles was set to 50 μm, and the minimum center-to-center spacing was set to 60 μm. The hexagonalness H of each circle placed in the area by the algorithm was 0.41. Since this hexagonalness is low, the degree of randomness is considered to be high. The graph reproduced in Figure 9 is a histogram showing the ratio of all objects placed in the area as a function of the center-to-center spacing with the nearest object.

[0109] Next, etching masks were formed on four glass substrate samples so as to superimpose the object placement according to this algorithm. Each sample's etching mask was configured to allow etching of the substrate in areas where objects were placed according to this algorithm, while preventing etching of the substrate in areas where no objects were placed. Subsequently, all four substrate samples with the etching masks attached were brought into contact with an etching solution. The etching solution formed surface features across the entire texture area, where objects were placed according to the algorithm, resulting in a recessed shape compared to the surrounding areas. Two of these samples were then separated into Examples 3C and 3D as comparative examples.

[0110] After etching, the etching masks were left attached to the substrate samples of Examples 3A and 3B. Then, a high refractive index material, specifically AlN, with a refractive index higher than that of the substrate (~1.51), was deposited into each surface feature area by reactive sputtering. Subsequently, the etching masks were removed from each substrate sample. Due to the effects of the manufacturing process and slight shadows created during deposition, the filling density of the high refractive index material AlN was in the range of 30-35%.

[0111] Next, all samples from Examples 3A to 3D were subjected to various optical measurements. Specifically, pixel power deviation ("PPD"), transmittance, transmitted haze ("haze"), image clarity ("DOI"), and specular reflectance were measured. Table 2 below shows the measurement results for each sample, along with the air trench depth and the height of the high refractive index material AlN deposited within each surface feature area ("AlN height"). The "air trench depth" values ​​for Examples 3C and 3D indicate the depth of the surface feature area relative to the periphery (since AlN was not added in Examples 3C and 3D).

[0112] [Table 2]

[0113] Analysis of the data in Table 2 revealed that in Examples 3A and 3B, by incorporating a high refractive index material into the surface feature area, the pixel power deviation was significantly reduced compared to both Examples 3C and 3D without significantly adversely affecting other optical property measurements. In Examples 3A and 3B, the image clarity value is less than 85%, indicating that specular reflection was suppressed.

[0114] Preferred embodiments of the present invention are described below in separate sections.

[0115] Embodiment 1 A substrate for display articles, Main surface and, A texture region provided on at least a part of the main surface, One or more high-level surfaces located at a high mean height parallel to a reference plane, which are provided below the texture region so as to extend through the substrate, One or more lower planes located at a lower mean altitude parallel to the reference plane, which is lower than the aforementioned higher mean altitude, and A high refractive index material disposed on each of the one or more low-level surfaces located at the low-level mean altitude, forming one or more intermediate surfaces located at an intermediate mean altitude parallel to the reference plane, which is higher than the low-level mean altitude and lower than the high-level mean altitude, and having a refractive index higher than the refractive index of the substrate or the low-refractive index material forming the one or more high-level surfaces. A texture area including, A circuit board equipped with the following features.

[0116] Embodiment 2 The median mean height of the high refractive index material is lower than the upper mean height of one or more upper surfaces by a distance within the range of 100 nm to 190 nm. The average lower altitude of the one or more lower surfaces is lower than the average upper altitude of the one or more upper surfaces by a distance within the range of 220 nm to 370 nm. The substrate according to Embodiment 1, wherein the median mean height of the high refractive index material is higher by a distance within the range of 100 nm to 200 nm than the lower mean height of one or more lower surfaces.

[0117] Embodiment 3 The refractive index of the substrate or the low refractive index material is within the range of 1.4 to 1.6. The substrate according to Embodiment 1 or 2, wherein the refractive index of the high refractive index material is in the range of 1.6 to 2.3.

[0118] Embodiment 4 The substrate according to any one of Embodiments 1 to 3, wherein the high refractive index material is an area on a plane that is (i) parallel to the reference plane and (ii) extends through the high refractive index material, and which occupies 22% to 49% of the area defined by the texture region.

[0119] Embodiment 5 The substrate according to any one of Embodiments 1 to 4, wherein the substrate includes a glass substrate or a glass ceramic substrate.

[0120] Embodiment 6 A substrate for display articles, Main surface and, A texture region provided on at least a part of the main surface, One or more high-level surfaces located at a high mean height parallel to a reference plane, which are provided below the texture region so as to extend through the substrate, One or more lower surfaces located at a lower mean altitude parallel to the reference plane, which is lower than the aforementioned higher mean altitude, A surface feature portion provided so as to protrude from or be recessed from the peripheral portion of the main surface, wherein (i) the surface feature portion forms one of the one or more high surfaces and the one or more low surfaces, and (ii) the peripheral portion forms the other of the one or more high surfaces and the one or more low surfaces that is different from the surface feature portion, and A high refractive index material disposed on one or more low-level surfaces located at the low-level mean altitude, wherein (i) the refractive index is higher than that of the substrate or the low-level materials forming the one or more high-level surfaces, and (ii) the high refractive index material has one or more intermediate surfaces located at an intermediate mean altitude parallel to the reference plane, between the high-level mean altitude and the low-level mean altitude. A texture area including, A circuit board equipped with the following features.

[0121] Embodiment 7 The aforementioned surface feature portion is provided so as to be recessed from the peripheral portion. The substrate according to Embodiment 6, wherein the high refractive index material is disposed on one or more lower surfaces located at the lower mean height formed by the surface feature portion within each surface feature portion.

[0122] Embodiment 8 The substrate according to Embodiment 6 or 7, wherein the median mean height of the high refractive index material is lower by a distance within the range of 120 nm to 190 nm than the high mean height of one or more high surfaces.

[0123] Embodiment 9 The substrate according to any one of embodiments 6 to 8, wherein the lower mean altitude is lower than the higher mean altitude by a distance within the range of 220 nm to 370 nm.

[0124] Embodiment 10 The substrate according to any one of embodiments 6 to 9, wherein the median mean height of the high refractive index material is higher by a distance within the range of 100 nm to 200 nm than the lower mean height of one or more lower surfaces.

[0125] Embodiment 11 The substrate according to any one of embodiments 6 to 10, wherein the refractive index of the substrate or the low refractive index material is in the range of 1.4 to 1.6.

[0126] Embodiment 12 A substrate according to any one of embodiments 6 to 11, wherein the refractive index of the high refractive index material is in the range of 1.6 to 2.3.

[0127] Embodiment 13 Each surface feature portion has an outer circumference parallel to the reference plane, A substrate according to any one of embodiments 6 to 12, wherein the outer periphery of each surface feature portion is circular or elliptical.

[0128] Embodiment 14 Each surface feature portion has an outer circumference parallel to the reference plane, A substrate according to any one of embodiments 6 to 12, wherein the outer circumference of each surface feature portion has a maximum dimension in the range of 5 μm to 200 μm.

[0129] Embodiment 15 The substrate according to any one of embodiments 6 to 14, wherein the arrangement of the surface feature portions is not a repeating arrangement but an arrangement that reflects a random distribution.

[0130] Embodiment 16 The substrate according to any one of embodiments 6 to 14, wherein the surface feature portions are arranged in a random distribution such that the distance between the surface feature portions satisfies the minimum distance between centers.

[0131] Embodiment 17 The aforementioned high refractive index material is AlNx SiO x N y , or SiN x A substrate according to any one of embodiments 6 to 16, including the substrate described therein.

[0132] Embodiment 18 The substrate according to any one of Embodiments 6 to 17, wherein the high refractive index material is an area on a plane that is (i) parallel to the reference plane and (ii) extends through the high refractive index material, and which occupies 22% to 49% of the area defined by the texture region.

[0133] Embodiment 19 The substrate according to any one of embodiments 6 to 18, wherein the substrate includes a glass substrate or a glass ceramic substrate.

[0134] Embodiment 20 The aforementioned texture region exhibits a pixel power deviation within the range of 1.2% to 2.1%. The aforementioned texture area exhibits a transparent haze in the range of 1.5% to 2.5%. The aforementioned texture region exhibits a specular reflectance in the range of 0.5% to 1.75%. The substrate according to any one of embodiments 6 to 19, wherein the textured area exhibits an image clarity in the range of 25% to 85%.

[0135] Embodiment 21 A method for forming a textured area on a substrate for display articles, A step of forming a texture region by forming surface feature portions on the main surface of a substrate that protrude from or are recessed from the peripheral portion, according to the predetermined positioning of each surface feature portion, (i) One or more of the higher surfaces of the texture region are located at a higher mean height parallel to a reference plane that extends below the texture region through the substrate, (ii) One or more lower surfaces of the texture region are located at a lower mean altitude parallel to the reference plane, which is lower than the upper mean altitude, (iii) The surface feature portion is one of the one or more high-level surfaces and the one or more low-level surfaces, (iv) The step of forming a surface feature portion such that the peripheral portion is the other surface of the one or more high surfaces and the one or more low surfaces that is different from the surface feature portion, The step includes depositing a high refractive index material on one or more lower surfaces located at the lower mean height among the surface feature portion and the peripheral portion, A method wherein the high refractive index material has (i) a refractive index higher than the refractive index of the substrate, and (ii) one or more intermediate planes located at an intermediate mean altitude parallel to the reference plane, between the high mean altitude and the low mean altitude.

[0136] Embodiment 22 The method according to Embodiment 21, further comprising the step of establishing the predetermined position of each surface feature portion by determining the position of each surface feature portion using a spacing distribution algorithm.

[0137] Embodiment 23 The method further includes the step of placing on the main surface an etching mask that prevents etching at locations where the surface feature portion is formed according to the predetermined positioning of the surface feature portion, or an etching mask that allows etching only at locations where the surface feature portion is formed according to the predetermined positioning of the surface feature portion. The method according to Embodiment 22, wherein the step of forming the surface feature portion includes the step of bringing at least the main surface of the substrate into contact with an etching solution while the etching mask is placed on the main surface of the substrate.

[0138] Embodiment 24 The method according to Embodiment 23, wherein the step of depositing the high refractive index material is performed after the surface feature portion has been formed, with the etching mask placed on the main surface.

[0139] Embodiment 25 The method according to Embodiment 24, further comprising the step of removing an etching mask after depositing the high refractive index material. [Explanation of Symbols]

[0140] 10 Display items 12 circuit boards 14 cabinets 16 displays 18 Main surface 20 Texture Area 22 Thickness 24 External environment 26 High plane 28 High average altitude 30 Reference plane 32 Lower plane 34 Lower average altitude 36 High refractive index materials 38 Intermediate Surface 40 medium average altitude 42 Distance (Trench Depth) 44. Distance (height of high refractive index material) 46 Distance (Air Trench Depth) 48 areas 50 planes 52 Surface Features 54 Peripheral area 56 Outer perimeter 58 Maximum dimensions 60 Minimum center distance 108 objects 110 Areas 112 Minimum center distance 116 Etching Mask 118 Etching solution 120 tanks

Claims

1. A substrate for display articles, Main surface and, A texture region provided on at least a part of the main surface, One or more high-level surfaces located below the texture region and at a high-level mean height parallel to a reference plane extending through the substrate, One or more lower planes located at a lower mean altitude parallel to the reference plane, which is lower than the aforementioned higher mean altitude, and A high refractive index material disposed on each of the one or more low-level surfaces located at the low-level mean altitude, which forms one or more intermediate surfaces located at an intermediate mean altitude parallel to the reference plane, higher than the low-level mean altitude and lower than the high-level mean altitude, and having a refractive index higher than the refractive index of the substrate or the one or more high-level surfaces. A texture area including, Equipped with, The aforementioned texture region exhibits a pixel power deviation in the range of 1.2% to 2.1% and a specular reflectance in the range of 0.5% to 1.75%. The refractive index of the substrate or the low refractive index material is in the range of 1.4 to 1.6, and A substrate in which the refractive index of the high refractive index material is in the range of 1.6 to 2.

3.

2. The substrate according to claim 1, wherein the high refractive index material is an area on a plane that is (i) parallel to the reference plane and (ii) extends through the high refractive index material, and which occupies 22% to 49% of the area defined by the texture region.

3. The substrate according to claim 1, wherein the refractive index of the high refractive index material is higher than the refractive index of the substrate or the low refractive index material.

4. The substrate according to any one of claims 1 to 3, wherein the median mean height of the high refractive index material is lower than the upper mean height of one or more upper surfaces by a distance in the range of 130 nm to 180 nm.

5. The substrate according to any one of claims 1 to 4, wherein the textured region exhibits a specular reflectance of 0.5% to less than 0.85%.

6. The aforementioned texture region is Pixel power deviation within the range of 1.2% to less than 1.5%, Image clarity within the range of 25% to 85%. Image clarity of less than 50%, 2.5% or less transmitted haze, and Over 92% light transmittance A substrate according to any one of claims 1 to 5, wherein one or more of the following are represented.

7. The substrate according to any one of claims 1 to 6, wherein the median mean height of the high refractive index material is higher by a distance in the range of 100 nm to 200 nm than the lower mean height of one or more lower surfaces.

8. A method for forming a textured area on a substrate for display articles, A step of forming a texture region by forming surface feature portions on the main surface of a substrate that protrude from or are recessed from the peripheral portion, according to predetermined positioning of each surface feature portion, the step of forming a surface feature portion such that (i) one or more high surfaces of the texture region are located at a high mean height parallel to a reference plane provided so as to extend below the texture region through the substrate, and (ii) one or more low surfaces are located at a low mean height parallel to the reference plane, which is lower than the high mean height. The step includes depositing a high refractive index material on each of the one or more low-level surfaces located at the low-level mean altitude to form one or more intermediate surfaces located at an intermediate mean altitude parallel to the reference plane, which is higher than the low-level mean altitude and lower than the high-level mean altitude, The high refractive index material has a refractive index higher than the refractive index of the substrate or the low refractive index material forming one or more high-level surfaces. The aforementioned texture region exhibits a pixel power deviation in the range of 1.2% to 2.1% and a specular reflectance in the range of 0.5% to 1.75%. The refractive index of the substrate or the low refractive index material is in the range of 1.4 to 1.6, and A method wherein the refractive index of the high refractive index material is in the range of 1.6 to 2.

3.

9. The method according to claim 8, wherein the high refractive index material is an area on a plane that is (i) parallel to the reference plane and (ii) extends through the high refractive index material, and which comprises 22% to 49% of the area defined by the texture region.

10. The method according to claim 8 or 9, wherein the median mean height of the high refractive index material is higher than the lower mean height of one or more lower surfaces by a distance within the range of 100 nm to 200 nm.

11. A substrate for display articles, Main surface and, A texture region provided on at least a part of the main surface, One or more high-level surfaces located at a high mean height parallel to a reference plane, which are provided below the texture region so as to extend through the substrate, One or more lower surfaces located at a lower mean altitude parallel to the reference plane, which is lower than the aforementioned higher mean altitude, A surface feature portion provided so as to protrude from or be recessed from the peripheral portion of the main surface, wherein (i) the surface feature portion forms one of the one or more high surfaces and the one or more low surfaces, and (ii) the peripheral portion forms the other of the one or more high surfaces and the one or more low surfaces that is different from the surface feature portion, and A high refractive index material disposed on one or more low-level surfaces located at the low-level mean altitude, wherein (i) the refractive index is higher than that of the substrate or the low-level materials forming the one or more high-level surfaces, and (ii) the high refractive index material has one or more intermediate surfaces located at an intermediate mean altitude parallel to the reference plane, between the high-level mean altitude and the low-level mean altitude. A texture area including, Equipped with, The aforementioned texture region exhibits a pixel power deviation in the range of 1.2% to 2.1% and a specular reflectance in the range of 0.5% to 1.75%. The refractive index of the substrate or the low refractive index material is in the range of 1.4 to 1.6, and A substrate in which the refractive index of the high refractive index material is in the range of 1.6 to 2.

3.

12. The substrate according to claim 11, wherein the high refractive index material is an area on a plane that is (i) parallel to the reference plane and (ii) extends through the high refractive index material, and which comprises 22% to 49% of the area defined by the texture region.

13. The substrate according to claim 11 or 12, wherein the median mean height of the high refractive index material is higher by a distance within the range of 100 nm to 200 nm than the lower mean height of one or more lower surfaces.

Images