阅读说明：本技术 显示器装置 (Display device ) 是由 F·西纳毕 E·德根特 I·马林内 Z·哈比比 于 2019-08-07 设计创作，主要内容包括：本发明涉及一种显示器装置(10),所述显示器装置包括具有显示表面(7)的显示元件(20)和具有第一纹理化表面(1)的盖板玻璃板(30),所述显示器装置被配置成使得所述第一纹理化表面(1)面向所述显示元件。所述第一纹理化表面(1)具有由等于或大于0.12μm的第一算术幅值Ra1(Ra1≥0.12μm)和等于或大于45μm的第一间距值Rsm1(Rsm1≥45μm)定义的表面粗糙度,所述第一算术幅值和所述第一间距值均是在12mm的评价长度上使用截止波长为0.8mm的高斯滤波器测量的。所述第一纹理化表面在所述第一纹理化表面的接触区域的至少一部分上与所述显示表面直接接触。(The invention relates to a display device (10) comprising a display element (20) having a display surface (7) and a cover glass plate (30) having a first textured surface (1), the display device being configured such that the first textured surface (1) faces the display element. The first textured surface (1) has a surface roughness defined by a first arithmetic amplitude Ra1(Ra1 ≧ 0.12 μm) equal to or greater than 0.12 μm and a first spacing value Rsm1(Rsm1 ≧ 45 μm) equal to or greater than 45 μm, both measured over an evaluation length of 12mm using a Gaussian filter with a cutoff wavelength of 0.8 mm. The first textured surface is in direct contact with the display surface over at least a portion of a contact area of the first textured surface.)

1. A display device (10) comprising a display element (20) having a display surface (7) and a cover glass plate (30) having a first textured surface (1), the display device being configured such that the first textured surface (1) faces the display element,

wherein the first textured surface (1) has a surface roughness defined by a first arithmetic amplitude Ra1(Ra1 ≧ 0.12 μm) equal to or greater than 0.12 μm and a first spacing value Rsm1(Rsm1 ≧ 45 μm) equal to or greater than 45 μm, both measured over an evaluation length of 12mm using a Gaussian filter with a cutoff wavelength of 0.8mm,

wherein the first textured surface is in direct contact with the display surface over at least a portion of a contact area of the first textured surface.

2. The display device of claim 2, wherein the display surface is textured to exhibit a surface roughness defined by a display arithmetic magnitude, Rad, and wherein the direct contact is such that an average distance, Dav, between the first textured surface of the cover glass plate and the display surface over the contact region is less than or equal to a sum of the first arithmetic magnitude, Ra1, and the display arithmetic magnitude, Rad (Dav ≦ (Ra1+ Rad)).

3. A display device according to any of the preceding claims, wherein the first arithmetic magnitude Ra1 of the cover glass plate is comprised in the range 0.12 μm Ra1 ≦ 0.5 μm, preferably in the range 0.12 μm Ra1 ≦ 0.25 μm, more preferably in the range 0.15 μm Ra1 ≦ 0.25 μm.

4. A display device according to any of the preceding claims, wherein the cover glass plate has a second textured surface presenting a surface roughness defined by a second arithmetic magnitude Ra2(Ra2 ≧ 0.08 μm) equal to or greater than 0.08 μm and a second spacing value Rsm2(Rsm2 ≧ 45 μm) equal to or greater than 45 μm, both measured over an evaluation length of 12mm using a Gaussian filter with a cutoff wavelength of 0.8 mm.

5. A display device according to any of the preceding claims, wherein the second arithmetic magnitude Ra2 of the cover glass plate is comprised in the range 0.08 μm Ra2 ≦ 0.5 μm, preferably in the range 0.08 μm Ra2 ≦ 0.25 μm, more preferably in the range 0.09 μm Ra2 ≦ 0.25 μm.

6. A display device according to any of the preceding claims, wherein the first pitch value of the cover glass plate Rsm1 is comprised in the range 45 μm Rsm1 ≦ 200 μm, preferably in the range 45 μm Rsm1 ≦ 100 μm, more preferably in the range 50 μm Rsm1 ≦ 100 μm.

7. A display device according to any of the preceding claims, wherein the second distance value of the cover glass plate Rsm2 is comprised in the range 45 μm Rsm2 ≦ 200 μm, preferably in the range 45 μm Rsm2 ≦ 100 μm, more preferably in the range 50 μm Rsm2 ≦ 100 μm.

8. A display device according to any of the preceding claims, wherein the 60 ° gloss value of the second textured surface is comprised in the range of 50SGU to 120SGU, preferably in the range of 60SGU to 110 SGU.

9. A display device according to any of the preceding claims, wherein the cover glass sheet has a total transmission haze value Hazetot equal to or less than 10% (Hazetot ≦ 10%), preferably equal to or less than 8% (Hazetot ≦ 8%), more preferably equal to or less than 5% (Hazetot ≦ 5%).

1. Field of the invention

The present invention relates to a display device providing excellent anti-newton ring characteristics.

2. Background of the invention

Touch display applications and digital signal applications typically include a display element separated from a cover glass plate by an air gap. This air gap generally helps prevent the cover glass plate from contacting the display element and improves ventilation.

In recent years, the size of display devices has increased. The current average size is about 65 inches, and it is expected that the future average size of the display will reach 75 inches, and even greater. Furthermore, there is a demand in the market for reducing the total weight of the display device. One of the elements is the thickness of the cover glass plate, which should be kept as small as possible.

Increasing the size of the cover glass sheet raises technical problems in providing a cover glass sheet with higher flexibility. In fact, for similar finger pressure, the glass buckling in the center of the cover glass plate is proportional to the square of the glass length. Maintaining a minimum thickness of the cover glass sheet also contributes to the flexibility of the glass. Thus, the chance of such a cover glass plate touching the display element is indeed significantly increased. First, friction between the cover glass plate and the display element mechanically damages the surface of the display element. Secondly, when the cover glass plate is pressed by a user's finger and brought into contact with the display element, newton rings are generated around the contact portion.

One solution provided in the art to avoid newton's rings is to increase the air gap between the display element and the cover glass plate. However, increasing the air gap increases the parallax phenomenon, whereby the displacement or difference in the apparent position of objects viewed along two different lines of sight increases. Another solution is to glue the cover glass plate to the display element, thereby avoiding parallax errors. However, this solution is very expensive, difficult to handle and does not allow for deconstruction and reconstruction in case of failure of the display device.

US 2013/0008767 solves the technical problem of newton rings and the glare phenomenon known as glare in touch panel applications, and provides a newton ring-preventing sheet having an uneven layer formed substantially of a polymer resin by arranging a plurality of structures having peaks in a lattice shape.

US 2016/0221315 solves the technical problem of blocking resistance, resistance to newton rings and obtaining sharp images by providing a laminated film for a touch panel device. US 2016/0221315 teaches the use of a laminate comprising a substrate, a refractive index adjustment layer on a first surface of the substrate, a transparent conductive layer on an opposite surface, and a fine textured layer on a second surface, the fine textured layer having an average spacing between raised portions of 400nm or less.

JP 2012252038 discloses an optical film which can improve an anti-glare property or an anti-newton ring property and can display a clear image without whitening. This optical film includes a transparent film and a hard coat layer formed on the transparent film, wherein an uneven structure is formed on a surface of the hard coat layer, an average spacing Sm of the uneven structure between apexes of protrusions is in a range of 600 to 1500 μm and an arithmetic average roughness Ra is 0.04 to 0.2 μm. The hard coating layer is formed by curing a composition including a curable resin precursor and cellulose nanofibers of a specific diameter and length.

There is a need to provide a cost-effective and efficient solution for designing display devices, in particular large-sized display devices, which provide anti-newton-ring properties.

3. Summary of the invention

The present invention relates to a display device comprising a display element having a display surface and a cover glass plate having a first textured surface, the display device being configured such that the first textured surface faces the display element. The first textured surface has a surface roughness defined by a first arithmetic amplitude Ra1(Ra1 ≧ 0.12 μm) equal to or greater than 0.12 μm and a first spacing value Rsm1(Rsm1 ≧ 45 μm) equal to or greater than 45 μm, both measured using a Gaussian filter with a cutoff wavelength of 0.8mm over an evaluation length of 12 mm. The first textured surface is in direct contact with the display surface over at least a portion of a contact area of the first textured surface.

Other aspects and advantages of the embodiments will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the described embodiments.

4. Description of the drawings

Fig. 1 shows a cross-sectional view of a prior art display device comprising device elements and a cover glass plate.

FIG. 2 illustrates a cross-sectional view of a display device including device elements and a cover glass plate according to one embodiment of the invention.

5. Detailed description of the preferred embodiments

An object of the present invention is to provide a display device including a display element and a cover glass plate, which exhibits excellent anti-newton ring characteristics particularly when designed in a large size.

Accordingly, the present invention relates to a display device comprising a display element having a display surface and a cover glass plate having a first textured surface, the display device being configured such that the first textured surface faces the display element. The first textured surface of the cover glass sheet has a surface roughness defined by a first arithmetic amplitude Ra1(Ra1 ≧ 0.12 μm) equal to or greater than 0.12 μm and a first spacing value Rsm1(Rsm1 ≧ 45 μm) equal to or greater than 45 μm, both the first arithmetic amplitude and the first spacing value measured over an evaluation length of 12mm using a Gaussian filter with a cutoff wavelength of 0.8 mm. The first textured surface is in direct contact with the display surface over at least a portion of a contact area of the first textured surface.

In fact, it has been surprisingly found that by texturing the inner surface of the glass sheet of the present invention to provide a surface roughness defined by a first arithmetic magnitude Ra1(Ra1 ≧ 0.12 μm) equal to or greater than 0.12 μm and a first spacing value Rsm1(Rsm1 ≧ 45 μm) equal to or greater than 45 μm, such textured inner surface of the cover glass sheet can be brought into direct contact with the surface of the display element without generating Newton rings and without mechanically damaging the surface of the display element.

The cover glass plate has a first textured surface (1) and a second surface (2), which may also be further textured. In the display device of the invention, the first textured surface faces the display element and may therefore also be referred to as inner surface. The second surface faces the exterior of the display device and may also be referred to as an exterior surface. The second outer surface of the cover glass sheet is spaced from the first inner surface by the thickness of the cover sheet.

Fig. 1 illustrates a prior art display device (10) in which a cover glass plate (30) is typically separated from a display element (20) by a spacer (3) defining an air gap (4) and protected by a protective frame (5).

Fig. 2 shows a display device according to the invention, wherein the first textured surface (1) of the cover glass plate (30) is in direct contact with the display surface (7) of the display element (20) without any spacers and is protected by a protective frame (5).

Infrared touch sensors (6) may be used and are located between the cover glass plate and the protective frame.

The display element has a display surface that may be smooth (i.e., not textured) and thus have a surface roughness defined by an arithmetic magnitude Ra0(Ra0 ≦ 0.2nm) equal to or less than 0.2 nm.

In another embodiment, the display element has a display surface which may be textured and thus has a surface roughness defined by the display arithmetic magnitude Rad and the first pitch value Rsmd.

In a preferred embodiment, the direct contact between the first textured surface of the cover glass plate and the display surface of the display element is such that the average distance Dav over the contact area between the first textured surface of the cover glass plate and the display surface is equal to or less than the sum of the first arithmetic magnitude Ra1 and the display arithmetic magnitude Rad (Dav ≦ (Ra1+ Rad)).

The glass cover plate extends over a length L measured parallel to the longitudinal axis X and over a width W measured parallel to the transverse axis Y (perpendicular to X). In a preferred embodiment, the contact area portion is equal to or greater than 50%, preferably equal to or greater than 80%, more preferably equal to or greater than 90%, even more preferably equal to or greater than 100% of the surface of the glass cover plate projected onto a plane parallel to X and Y. In embodiments where the size of the cover glass plate is larger than the size of the display element, the contact area portion may indeed be larger than 100%, preferably equal to or larger than or equal to 110%.

The cover glass plate of the display device of the present invention has a first surface facing the display element. The first face is textured to present a surface roughness defined by a first arithmetic amplitude Ra1(Ra1 ≧ 0.12 μm) equal to or greater than 0.12 μm and a first spacing value Rsm1(Rsm1 ≧ 45 μm) equal to or greater than 45 μm, both measured over an evaluation length of 12mm using a Gaussian filter with a cutoff wavelength of 0.8 mm.

In a preferred embodiment, the first arithmetic magnitude Ra1 is included in the range 0.12 μm Ra1 0.5 μm, preferably 0.12 μm Ra1 0.25 μm, and more preferably 0.15 μm Ra1 0.25 μm. In a preferred embodiment, the first pitch value Rsm1 is included in the range 45 μm Rsm1 200 μm, preferably 45 μm Rsm1 100 μm, and more preferably 50 μm Rsm1 100 μm.

The second surface of the cover glass plate used in the display device of the present invention faces the outside of the display device. The second surface may be further textured to provide anti-glare and anti-haze properties.

In a preferred embodiment, the surface roughness of the second textured surface has a second arithmetic magnitude Ra2(Ra2 ≧ 0.08 μm) equal to or greater than 0.08 μm and a second spacing value Rsm2(Rsm2 ≧ 45 μm) equal to or greater than 45 μm, both measured using a Gaussian filter with a cutoff wavelength of 0.8mm over an evaluation length of 12 mm.

In another preferred embodiment, the arithmetic amplitude Ra2 is comprised within the range 0.08 μm Ra2 0.5 μm, preferably within the range 0.08 μm Ra2 0.25 μm, more preferably within the range 0.09 μm Ra2 0.25 μm. In a further preferred embodiment, the second pitch value Rsm2 is comprised within the range 45 μm Rsm2 ≦ 200 μm, preferably 45 μm Rsm2 ≦ 100 μm, more preferably 50 μm Rsm2 ≦ 100 μm.

Glare treats the external source of reflection off a surface, such as bright sunlight or high ambient lighting conditions. The anti-glare properties are measured by gloss optical properties. Anti-glare properties use a diffusion mechanism (such as texturing) to decompose the reflected light exiting the surface. Gloss characterizes the brightness or shine of a surface, and more specifically corresponds to the specular reflectance of the surface relative to a standard (e.g., an certified black glass standard). The Gloss was measured at a specific angle of 60 ° according to ASTM Standard D523-14 "Standard Test Method for Specular Gloss [ Standard Test Method for Specular Gloss ]" for 5, 4, 2017, and it was expressed in SGU (Standard Gloss units). According to an advantageous embodiment of the invention, the second surface of the cover glass sheet has a 60 ° gloss value from 50SGU to 120 SGU. More preferably, the glass sheet has a 60 ° gloss value from 60SGU to 110 SGU.

Light passing through the glass sheet may be affected by irregularities and surface roughness of the glass sheet, causing the light to scatter in different directions. The degree of light scattering depends on the size and amount of irregularities present and the amount of surface roughness. Light scattering is responsible for transmission haze due to loss of transmission contrast. The diffusion mechanism achieved by texturing, for example, has a negative effect on light reflection. Standard test method ASTM D1003-11 defines haze as the percentage of transmitted light that is scattered such that the direction of transmitted light deviates from the direction of the incident beam by an angle of more than 2.5 °.

In designing cover glass sheets for display applications, both haze and glare characteristics should indeed be considered to improve or optimize the readability of the displayed image or character set. Thus, there is a tradeoff between reducing glare of the surface and reducing haze of the surface, as increasing the texture/roughness of the glass surface typically results in a desirable reduction in glare, but an undesirable increase in haze. It has been found that texturing the second surface of the glass cover to have such arithmetic magnitude and spacing values provides excellent anti-haze and anti-glare properties.

For display applications, it is preferred that the cover glass sheet provide low total transmission haze. Thus, in preferred embodiments, the total transmission haze, i.e., the haze of a cover glass sheet with the first surface textured and the final second surface further textured, is preferably equal to or less than 10% (Hazetot ≦ 10%), preferably equal to or less than 8% (Hazetot ≦ 8%), more preferably equal to or less than 5% (Hazetot ≦ 5%). The Haze measurement was carried out according to ASTM Standard D1003-11 "Standard Test Method for Haze and luminescence Transmission of Transparent Plastics [ Standard Test Method for Haze and light Transmittance of Transparent Plastics ]" dated 11.2011, using light source A, according to procedure A, which was carried out by means of a Haze measuring instrument. Please refer to paragraph 7 of this standard test method.

Texturing glass surfaces is widely used in the display industry. Texturing may be produced by several known methods, like (i) removal of material from a smooth glass surface by chemical etching or sandblasting or (ii) application of a rough coating on a smooth surface by, for example, spraying, polymer mesh coating or dip coating.

According to the invention, both surfaces of the cover glass plate are textured. An "etched surface" refers to a surface that has been mechanically or chemically etched to remove an amount of glass material and impart a particular surface texture/roughness. We talk about chemically etched glass when material removal occurs by chemical reaction/attack (i.e., acid etching). We talk about mechanically etched glass when material removal occurs by mechanical reaction/erosion (i.e., sandblasting).

According to the invention, the textured surface may advantageously be textured over substantially the entire glass surface, i.e. over at least 90% of the glass surface.

The textured surface of a glass plate is generally characterized by its surface texture or roughness and, in particular, by the Ra and Rsm values (expressed in micrometers) defined in standard ISO 4287-. The texture/roughness is a result of the presence of surface irregularities/patterns. These irregularities consist of ridges called "peaks" and valleys called "valleys". In a cross-section perpendicular to the textured surface, these peaks and valleys are distributed on both sides of a "center line" (algebraic average), also called "bisector". In a profile and for measurements along a fixed length (called the "evaluation length"):

ra (magnitude) corresponds to the mean difference of the texture, meaning the arithmetic mean of the absolute values of the differences between these peaks and valleys. Ra measures the distance between the average and the "line" and gives an indication of the height of the pattern on the textured surface;

rsm (pitch value) is the average distance between two consecutive channels of the profile passing through the "bisector"; and this gives the average distance between these "peaks" and hence the average of the width of the pattern.

The roughness values according to the invention can be measured with a 2D profilometer (according to ISO4287 standard). Alternatively, 3D profilometry techniques (according to ISO 25178 standard) may be used, but a 2D profile is isolated, which 2D profile then allows the parameters defined in the ISO4287 standard to be obtained.

According to the invention, the roughness values are measured with a gaussian filter, which is a long-wavelength filter, also called contour filter λ c. It is used to separate the component of roughness/texture from the relief component of the contour.

The evaluation length L according to the present invention is a profile length used to evaluate roughness. The base length l is the portion of the evaluation length that is used to identify irregularities that characterize the contour to be evaluated. The evaluation length L is divided/sliced into n base lengths L, depending on the contour irregularity. The base length l corresponds to the "cut-off" wavelength (or limiting wavelength) of the gaussian filter (l ═ λ c). Typically, the evaluation length is at least five times the base length.

In roughness measurements, a short wavelength filter (profile filter λ s) is also typically used to eliminate the effect of very short wavelengths which are background noise.

The cover glass plate according to the invention is made of glass, the base composition of which is not particularly limited and can therefore belong to different categories. The glass may be a soda-lime-silicate glass, an aluminosilicate glass, an alkali-free glass, a borosilicate glass, or the like. Preferably, the glass sheet of the present invention is made of soda lime glass or aluminosilicate glass.

According to an embodiment of the invention, the glass sheet has a composition comprising, in a content expressed as a percentage of the total weight of the glass:

in a preferred manner, the glass sheet has the following composition, said composition comprising, in a content expressed as a percentage of the total weight of the glass:

in a more preferred manner, the glass sheet has a composition comprising, in a content expressed as a percentage of the total weight of the glass:

this soda-lime type base glass composition has the advantage of being inexpensive, even though it is itself mechanically less tolerant.

Ideally, according to this last embodiment, the glass composition does not contain B₂O₃(meaning that it is not intentionally added, but may be present as a very low amount of undesirable impurities).

In an alternative more preferred way, the glass sheet has a composition comprising, in a content expressed as a percentage of the total weight of the glass:

this aluminosilicate type base glass composition has the advantage of being mechanically more resistant, but it is more expensive than the soda-lime type.

Ideally, according to this last embodiment, the glass composition does not contain B₂O₃(meaning that it is not intentionally added, but may be present as a very low amount of undesirable impurities).

According to an advantageous embodiment of the invention, which can be combined with the previous embodiments with respect to the base glass composition, the glass sheet has a total iron (in Fe) content ranging from 0.002 to 0.06 wt. -%₂O₃Expressed) content. Less than or equal to 0.06 wt% total iron (as Fe)₂O₃Expressed in terms of form) content makes it possible to obtain a glass panel with little visible coloration and which allows a high degree of flexibility in the aesthetic design (for example, without deformation when performing white screen printing of some glass elements of a smartphone). This minimum value makes it possible not to cause excessive damage to the cost of the glass, since such low iron values often require expensive, very pure starting materials and also purification of these materials. Preferably, said composition comprises in the range of from 0.002 wt%To 0.04 wt.% of total iron (as Fe)₂O₃Expressed in terms of) content. More preferably, the composition comprises total iron (as Fe) in the range of from 0.002 wt% to 0.02 wt%₂O₃Expressed in terms of) content. In the most preferred embodiment, the composition comprises total iron (as Fe) in the range of from 0.002 wt% to 0.015 wt%₂O₃Expressed in terms of) content.

According to another embodiment of the invention, the iron oxide is Fe₂O₃The preceding embodiments can be combined at levels of glass having a composition comprising, expressed as a percentage of the total weight of the glass, for example, 0.0001% Cr ≦ Cr₂O₃Chromium content of less than or equal to 0.06 percent. Preferably, the glass has a glass composition comprising at least one of: 0.002% or more Cr₂O₃Chromium content less than or equal to 0.06 percent. This chromium content allows to obtain a glass with a higher IR transmittance, and it is therefore advantageous when using the glass sheet in a touch panel using optical IR touch technology, like for example Planar Scattering Detection (PSD) or Frustrated Total Internal Reflection (FTIR) (or any other technology requiring a high IR radiation transmittance), in order to detect the position of one or more objects (e.g. a finger or a stylus) on the surface of the glass sheet.

The glass sheet of the present invention may be a drawn glass sheet or a float glass sheet. According to an embodiment, the glass sheet of the invention is a float glass sheet. The term "float glass sheet" should be understood to mean a glass sheet formed by the float process, which includes pouring molten glass onto a bath of molten tin under reducing conditions. Float glass sheets comprise, in a known manner, a "tin face", i.e. a face rich in tin within the bulk of the glass close to the surface of the sheet. The term "tin-rich" should be understood to mean an increase in the tin concentration relative to the composition of the glass at the core, which may or may not be substantially zero (no tin). Thus, float glass sheets can be easily distinguished from sheets obtained by other glass manufacturing processes, in particular by the tin oxide content, which can be measured, for example, by an electronic microprobe to a depth of about 10 microns.

The glass sheet according to the invention may have a thickness of from 0.1mm to 25 mm. Advantageously, the glass sheet according to the invention may preferably have a thickness of from 0.1mm to 6 mm. More preferably, the cover glass plate according to the invention has a thickness of from 0.1 to 2.1mm for weight reasons.

The cover glass plate according to the invention may advantageously be a prestressed glass. The prestressed glass refers to heat-strengthened glass, heat-toughened glass or chemically-strengthened glass. Thermally treating the thermally strengthened glass using a controlled heating and cooling process that subjects the glass surface to compression and the glass core to tension. This heat treatment process provides glass having a flexural strength greater than annealed glass but less than thermally toughened safety glass.

Thermally treating the thermally toughened safety glass using a controlled heating and cooling process that subjects the glass surface to compression and the glass core to tension. Such stresses can cause the glass to break into small granular particles upon impact rather than breaking into jagged fragments. The granular particles are less likely to injure occupants or damage objects.

Chemical strengthening of glass articles is thermally induced ion exchange involving the replacement of smaller alkali sodium ions in the surface layers of the glass with larger ions (e.g., alkali potassium ions). Increased surface compressive stress occurs in the glass when larger ions "wedge" into small sites originally occupied by sodium ions. Such chemical treatment is typically carried out by immersing the glass in an ion-exchange molten bath of a molten salt containing one or more relatively large ions, under precise control of temperature and time. Aluminosilicate-type Glass compositions are also known, such as the product line from Asahi Glass CoOr product line from Corning Inc (Corning Inc.)Those) are very efficient for chemical tempering.

Various layers/treatments may be deposited/performed on the cover glass sheet of the present invention, on one or both sides of the cover glass sheet, depending on the desired application, intended use, and/or properties.

According to one embodiment of the invention, the glass plate is coated with at least one thin transparent and electrically conductive layer. The transparent and electrically conductive thin layer according to the invention may be based on SnO, for example₂:F、SnO₂Sb or ITO (indium tin oxide), ZnO Al or also ZnO Ga.

According to another embodiment of the invention, the glass plate is coated with at least one antireflection layer. Advantageously, according to this embodiment, the cover glass plate is coated on the second surface with said antireflection layer. This embodiment is advantageous in case the glass plate of the invention is used as a front cover of a screen. The antireflection layer according to the invention may be, for example, a layer based on porous silicon with a low refractive index or it may consist of several layers (stacks), in particular stacks of layers of alternating layers of dielectric material with a low and a high refractive index, and ending with a layer with a low refractive index.

According to yet another embodiment, the glass sheet has at least one anti-fingerprint layer/treatment to reduce or prevent the recording of fingerprints. Advantageously, according to this embodiment, the glass sheet has said anti-fingerprint layer/treatment on the second surface. Such layers/treatments may be combined with thin layers deposited on opposite sides that are transparent and conductive. Such layers/treatments may be combined with an anti-reflective layer deposited on the same side.

According to yet another embodiment of the invention the glass sheet is provided with an antimicrobial layer/treatment. Advantageously, according to this embodiment, the glass sheet has said antimicrobial layer/treatment on the second surface. For example, such an antimicrobial treatment may be the diffusion of silver ions in the bulk of the glass sheet to the vicinity of the outer surface.

Embodiments of the invention will now be further described, by way of example only, together with some comparative examples which are not in accordance with the invention. The following examples are provided for illustrative purposes and are not intended to limit the scope of the present invention.

Examples of the invention

Gloss measurements were made by a Gloss meter-Micro-Tri Gloss of BYK at a specific angle of 60 ° according to ASTM standard D523. The surface roughness measurements were performed using a 3D optical profiler Leica type DCM3D, using "Leica map" software, over an evaluation length of 12mm with a gaussian filter with a cut-off wavelength of 0.8 mm. The sample was first washed with detergent and dried. It is then placed under a microscope and after regular setup, the profile of the 2D acquisition is then started (the software applies a default cutoff wavelength λ s of 2.5 microns). Haze was measured on a cover glass plaque by standard test method ATSM D1003 using illuminant A. Note that the haze value measured by the ATSM D1003 was the same regardless of which surface of the cover glass plate was illuminated in the haze meter.

The exemplary cover glass sheets of examples 1-3 were soda-lime compositions made from the following compositions in weight percent:

SiO2	73.27％
		Na2O	13.9％
CaO	7.9％
		MgO	4.5％
K2O	0.07％
		Al2O3	0.1％
SO3	0.2％
		TiO2	0.06％

examples 1 and 2

The display device is designed as a cover glass plate with the following examples 1 and 2, wherein the first textured surface is in direct contact with the display surface of the display element. The first surface of the cover glass plate has been textured as described in the table below and is positioned in direct contact with the display surface of the display element without creating newton's rings. Such cover glass sheets further provide excellent gloss and haze characteristics.

Example 3

The display device is designed as a cover glass plate with the following example 3, wherein the first textured surface is in direct contact with the display surface of the display element. The cover glass plate was prepared by coupling VRD VCLO 110 soda lime etched glass as the first inside surface of the cover glass plate to VRD VCLO 90 soda lime etched glass as the second outside surface of the cover glass plate by Immersion Index Liquid (Immersion Index) from Cargill corporation having a refractive Index of 1.52. VRD VCLO 90 and VRD VCLO 110 are Glass plates commercially available from Asahi Glass company of Europe (AGC Glass Europe).

The first surface of the cover glass plate is positioned in direct contact with the display surface of the display element without generating Newton rings. Such a cover glass sheet further provides excellent gloss and antifog properties.

Reference symbol #	Feature(s)
		10	Display device
20	Display element
		30	Cover glass plate
1	First surface of cover glass plate
		2	Second surface of cover glass plate
3	Spacer member
		4	Air gap
5	Protective frame
		6	Infrared touch sensor
7	Display surface