A cover plate

Abstract

The utility model relates to the technical field of cover plate discloses a kind of cover plate, the cover plate includes transparent substrate and plating film layer being plated in the transparent substrate surface, the cover plate includes plane portion and curved surface portion, define the thickness of plating film layer of plane portion as h1, the thickness of plating film layer of curved surface portion is h2, h1 and h2 are same, and h1>h2;Define the minimum value of visible light wave band as λ1, the maximum value of visible light wave band is λ2, λ1 and λ2 are all nm in unit;The reflectivity of the plating film layer of the plane portion of the cover plate in the range of light wavelength λ1~λ3≤3%, wherein λ3≥(λ2×h1 / h2).The utility model can effectively solve the arc edge heterochromatic problem after plating antireflection film, and a variety of cover plate schemes can be designed quickly and flexibly according to actual needs.

Description

Technical Field

[0001] This utility model relates to the field of cover plate technology, and specifically to a cover plate. Background Technology

[0002] Currently, after 3D curved surface coating of window protection products, the sputtering angle at the curved surface is greater than that on the flat surface. Due to the angle effect, the coating layer is thinner at the edge of the curved surface, resulting in higher reflectance of the spectral curve in the long-wavelength visible light band, which leads to the problem of color difference at the curved edge.

[0003] Especially for 3D curved surface coatings with large curvature, the existing film layer design technology will reduce the thickness of the 3D curved edge by more than 30%, and the problem of uneven color at the curved edge will be particularly obvious. Moreover, the hardness and durability of the film layer cannot meet the requirements.

[0004] The problem of uniform film thickness can be solved by the rotation of the equipment, but the equipment structure is complex, making maintenance difficult, resulting in poor appearance yield and making mass production difficult. Another problem of color difference caused by thinner film thickness at the curved edge is usually solved by using low refractive index materials with fewer coating layers, such as a single layer of MgF2 or a single layer of MgF2 superimposed with a thin layer of SiO2, etc. However, due to the characteristics of the material itself, the film hardness is low, and the film resistance to salt spray and alkaline sweat tests is relatively poor, which makes it unsuitable for actual production. Utility Model Content

[0005] The purpose of this invention is to provide a curved surface coated cover plate without the phenomenon of uneven color at the curved edge.

[0006] To achieve the above objectives, the present invention provides a cover plate, which includes a transparent substrate and a coating layer deposited on the surface of the transparent substrate. The cover plate includes a planar portion 1 and a curved portion, and the curved portion includes a curved middle portion 2 and a curved edge portion 3.

[0007] The thickness of the coating layer in the planar part 1 is defined as h1, and the thickness of the coating layer in the curved edge part 3 is defined as h2. The units of h1 and h2 are the same, and h1 > h2. The minimum value of the visible light band is defined as λ1, and the maximum value of the visible light band is defined as λ2. The units of λ1 and λ2 are both nm.

[0008] The reflectivity of the coating layer on the planar portion 1 of the cover plate is ≤3% in the range of light wavelength λ1~λ3, where λ3≥(λ2×h1 / h2).

[0009] Compared with the prior art, the present invention has at least the following advantages:

[0010] This invention can effectively solve the problem of uneven color on the curved edge after applying anti-reflective coating, and the reflectivity of the cover plate is lower than that of ordinary glass. This invention summarizes the core design principle and can quickly and flexibly design a variety of cover plate solutions according to actual needs. Attached Figure Description

[0011] Figure 1 This is a cross-sectional side view of the cover plate prepared according to this utility model.

[0012] Figure 2 This is a schematic diagram of a 5-layer coated cover plate structure according to this utility model;

[0013] Figure 3 This is a schematic diagram of a 7-layer coated cover plate structure according to this utility model;

[0014] Figure 4 This is a schematic diagram of a 12-layer coated cover plate structure according to the present invention;

[0015] Figure 5 The reflection curve is designed according to Embodiment 1 of this utility model;

[0016] Figure 6 This is the reflection curve designed in Comparative Example 1 of this utility model;

[0017] Figure 7 This is the reflection curve designed in Comparative Example 2 of this utility model;

[0018] Figure 8 This utility model provides a comparative example 3 showing the design of a reflection curve.

[0019] Figure 9 This utility model relates to a 7-layer coated cover plate that reduces the reflection curves of different film thicknesses;

[0020] Figure 10 It is a common anti-reflective coating cover plate that reduces the reflection curves of different film thicknesses;

[0021] Figure 11 This utility model optimizes the back cover to reduce the reflection curves of different film thicknesses;

[0022] Figure 12 This utility model is a 3D colorless cover plate that reduces the reflection curves of different film thicknesses.

[0023] Explanation of reference numerals in the attached figures

[0024] 1. Planar portion; 2. Middle portion of curved surface; 3. Edge portion of curved surface;

[0025] 001 Transparent substrate; 101 Medium refractive index layer; 201 High refractive index layer; 301 Low refractive index layer; 401 High refractive index layer; 501 Low refractive index layer;

[0026] 002 Transparent substrate; 102 Medium refractive index layer; 202 High refractive index layer; 302 Low refractive index layer; 402 High refractive index layer; 502 Low refractive index layer; 602 High refractive index layer; 702 Low refractive index layer;

[0027] 003 Transparent substrate; 103 Medium refractive index layer; 203 Low refractive index layer; 303 High refractive index layer; 403 Low refractive index layer; 503 High refractive index layer; 603 Low refractive index layer; 703 High refractive index layer; 803 Low refractive index layer; 903 High refractive index layer; 1003 Low refractive index layer; 1103 High refractive index layer; 1203 Low refractive index layer. Detailed Implementation

[0028] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0029] In this invention, unless otherwise stated, the “inner” and “outer” of the coating layer refer to the side closer to the transparent substrate as the inner side and the side in contact with the external environment as the outer side.

[0030] In this utility model Figures 5 to 8 In the diagram, the reflection curves from left to right represent the film thickness -10% and the original thickness, respectively. In this utility model... Figures 9 to 11 In the diagram, the reflection curves from left to right represent film thickness -30%, film thickness -20%, film thickness -10%, and the original thickness, respectively.

[0031] In this invention, "original thickness" refers to the thickness of the coating layer on the planar portion, and "film thickness -30%" means that the thickness of the coating layer on the curved edge portion is reduced by 30% compared to the planar portion. Similar expressions in other parts of this invention have the same definition and will not be described in detail here.

[0032] In this invention, the minimum value λ1 and the maximum value λ2 of the visible light band refer to the conventional definition of the visible light band in the art. For example, it can be understood that the minimum value λ1 is 380nm and the maximum value λ2 is 750nm. However, different sources define the boundary values ​​slightly differently, for example, 400nm-700nm, or 380nm-700nm, or 380nm-780nm. The technical solution of this invention is applicable to all defined ranges of the visible light band.

[0033] like Figure 1As shown, a cover plate includes a transparent substrate and a coating layer deposited on the surface of the transparent substrate. The cover plate includes a planar portion 1 and a curved portion, and the curved portion includes a curved middle portion 2 and a curved edge portion 3.

[0034] The thickness of the coating layer in the planar part 1 is defined as h1, and the thickness of the coating layer in the curved edge part 3 is defined as h2. The units of h1 and h2 are the same, and h1 > h2. The minimum value of the visible light band is defined as λ1, and the maximum value of the visible light band is defined as λ2. The units of λ1 and λ2 are both nm.

[0035] The reflectivity of the coating layer on the planar portion 1 of the cover plate is ≤3% in the range of light wavelength λ1~λ3, where λ3≥(λ2×h1 / h2).

[0036] In the preferred embodiment, λ3 = (λ2 × h1 / h2). Under this preferred condition, the present invention can overcome the problem of uneven color at the curved edge of the cover plate, and the thickness of the cover plate is smaller, thus reducing production costs.

[0037] like Figure 1 As shown, in this utility model, the angle between the middle part 2 of the curved surface and the plane is θ1, and the angle between the edge part 3 of the curved surface and the plane is θ2. The angle between the edge part 3 of the curved surface and the plane is the largest, and the film layer is the thinnest at the point where the film layer is relative to the plane.

[0038] In existing coated curved glass products, the coating layer on the curved surface is thinner than that on the flat surface due to the sputtering angle being greater. This angle effect results in a thinner coating on the curved surface compared to the flat surface, leading to color differences. This invention utilizes the visible light band within the λ1~λ2 range, where wavelengths above λ2 are invisible. Therefore, the maximum wavelength of the visible light band on the flat surface is designed to be greater than λ2, for example, 900nm. Since wavelengths above λ2 are invisible, the color is not affected. Furthermore, the curved surface of the product is thinned, reducing the wavelength from 900nm to λ2. Therefore, from the final appearance, the cover plate provided by this invention will not exhibit color variations.

[0039] This utility model provides, by way of example, such as Figure 10 , Figure 11 and Figure 12 This invention illustrates the design principle of the present invention. The reflection curve of a typical AR (anti-reflective coating) layer is shown below. Figure 10As shown in the figure, the reflection curves from left to right represent film thickness -30%, film thickness -20%, film thickness -10%, and the original thickness. It can be seen from the figure that as the thickness of the curved coating layer gradually decreases, the reflection curve of the coating layer gradually shifts to the left. Typically, the design prioritizes low reflection in the 400nm–700nm range and high reflection in other wavelengths. However, this shift causes the curves above 700nm to shift to the left, resulting in high reflection in the 400nm–700nm range, leading to a reddish or yellowish color. The full-band reflection curve optimized by the design principle of this invention is shown below. Figure 11 As shown in the figure, even though the reflection curve shifts to the left due to the reduced thickness of the curved coating layer after optimization, the reflectivity remains ≤3% in the visible light range of 400nm to 700nm, exhibiting low reflectivity. Therefore, the cover plate will not exhibit color variation at the curved edge. The cover plate provided by this invention can still achieve the same effect even if the curved portion is thinned due to the angle effect. Figure 12 The reflection curve shown indicates low and stable low reflection in the visible light band.

[0040] In some preferred embodiments, the reflectivity of the coating layer on the planar portion 1 of the cover plate is ≤1% in the range of light wavelengths λ1 to λ3, preferably ≤0.5%. In this preferred case, the cover plate provided by the present invention exhibits smaller reflectivity fluctuations and stable low reflectivity.

[0041] In a preferred embodiment, the value of h1 / h2 is 1.0-4.3, and more preferably 1.0-2.0.

[0042] In some preferred embodiments, the coating layer includes a first coating layer and a second coating layer from the inside out; the first coating layer is a medium refractive index layer, and the second coating layer includes at least one high refractive index layer and at least one low refractive index layer stacked alternately in sequence; the outermost layer of the coating layer is a low refractive index layer.

[0043] Preferably, the thickness of the coating layer is 200nm~600nm, more preferably 200nm~400nm.

[0044] Preferably, the sum of the number of layers of the first coating layer and the second coating layer is 5 to 12 layers, more preferably 5 to 7 layers.

[0045] Preferably, the high refractive index layer material has a refractive index of 1.9~2.2 and an extinction coefficient K < 0.001. Preferably, the high refractive index layer material has a nanohardness of 13 GPa or higher.

[0046] Preferably, the material of the high refractive index layer is selected from at least one of SiAlN, AlN, Si3N4, TiO2, NB2O5, SiON, SiAlON, and AlON.

[0047] In a preferred embodiment, the refractive index of the material of the intermediate refractive index layer is 1.6 to 1.7, and the extinction coefficient K is less than 0.001.

[0048] Preferably, the material of the intermediate refractive material layer is selected from at least one of SiON, Al2O3, AlON, and SiAlO.

[0049] In a preferred embodiment, the refractive index of the low refractive index layer is 1.4 to 1.5, and the extinction coefficient K is less than 0.001.

[0050] Preferably, the material of the low-refractive-index layer is selected from at least one of MgF2, SiON, SiO2, AlON, and SiAlO.

[0051] In this invention, the materials of the high refractive index layer and the low refractive index layer are preferably resistant to salt spray, alkali, acid and organic solvent corrosion.

[0052] In this invention, salt spray resistance refers to the fact that the coating layer of the material deposited on the substrate is not damaged when it is placed in a salt spray chamber at a temperature of 35±2℃, a NaCl solution concentration of 5±1wt%, and a solution pH of 6.5~7.2 for 48 hours.

[0053] In this invention, the alkali resistance refers to the fact that when the material plated on the substrate is placed in an incubator at 70°C for 24 hours while enveloped in an alkaline NaOH solution with a pH value of 9.5, the coating layer is not damaged.

[0054] In this invention, the acid resistance is demonstrated by placing the material coated on the substrate in an acidic solution with a pH value of 4.6±0.1 in an insulated box at a temperature of 55±2℃ and a humidity of 93±2% for 96 hours without damaging the coating layer.

[0055] In some preferred embodiments, the reflectivity of the cover plate is 5% to 6%, and the transmittance is 93% to 94%; the sum of the reflectivity and transmittance of the cover plate is > 99%.

[0056] Preferably, the nanohardness of the coating layer of the cover plate is 8~10 GPa.

[0057] According to a preferred embodiment of the present invention, the a value of the coating layer of the planar portion 1 is defined as a1, and the b value is defined as b1; the a value of the coating layer of the curved edge portion 3 is defined as a2, and the b value is defined as b2; |a2-a1|<0.8, |b2-b1|<2.

[0058] Preferably, a1 is selected from any value from 0.2 to 1.0, and b1 is selected from any value from -2.5 to 1.3.

[0059] The cover plate provided by this utility model can simultaneously meet the excellent performance requirements of low stress, low reflection, high transmittance, and high hardness, and has no problem of uneven color at the curved edge.

[0060] This invention can obtain a structure for a non-arc-edge, color-blocked cover plate coating that meets the requirements, based on the characteristics of different coating materials, the required coating thickness, and the band reflectivity design principle of this invention. The following specific embodiments are provided as examples of this invention.

[0061] Example 1

[0062] The film thickness at the curved edge is reduced by 10% compared to the flat portion, i.e., h1 / h2 = 1.11. The visible light wavelengths are λ1 = 400 nm, λ2 = 700 nm, and λ3 = 700 × 1.11 = 777 nm. The designed wavelength range for the coating is 400 nm to 777 nm. The reflectivity of the coating on the flat portion of the cover plate is ≤3% within the wavelength range λ1 to λ3. The specific structure is as follows... Figure 2 As shown in Table 1.

[0063] Table 1

[0064]

[0065] Reflection curves of curved edge parts and planar parts, such as Figure 5 As shown in Table 2, the color difference test results are as follows.

[0066] Table 2

[0067]

[0068] As can be seen from Table 2, the cover plate structure provided in this embodiment has small color difference and no uneven color phenomenon at the arc edge.

[0069] Comparative Example 1

[0070] The film thickness at the curved edge is reduced by 10% compared to the flat portion, i.e., h1 / h2 = 1.11. The visible light wavelengths are λ1 = 400 nm, λ2 = 700 nm, and λ3 = 763 nm. The designed wavelength range for the coating is 400 nm–763 nm. The reflectivity of the coating on the flat portion of the cover plate within the 400 nm–763 nm range is ≤3%. The specific structure is as follows... Figure 2 As shown in Table 3.

[0071] Table 3

[0072]

[0073] Reflection curves of curved edge parts and planar parts, such as Figure 6 As shown in Table 4, the color difference test results are as follows.

[0074] Table 4

[0075]

[0076] As can be seen from the table above, the color difference of the cover plate structure provided by this comparison is too large, and there is a phenomenon of different colors at the arc edge.

[0077] Comparative Example 2

[0078] The film thickness at the curved edge is reduced by 10% compared to the flat portion, i.e., h1 / h2 = 1.11. The visible light wavelengths are λ1 = 400 nm, λ2 = 700 nm, and λ3 = 756 nm. The designed wavelength range for the coating is 400 nm to 756 nm. The reflectivity of the coating on the flat portion of the cover plate is ≤3% within the 400 nm to 756 nm range. The specific structure is as follows... Figure 2 As shown in Table 5.

[0079] Table 5

[0080]

[0081] Reflection curves of curved edge parts and planar parts, such as Figure 7 As shown in Table 6, the color difference test results are as follows.

[0082] Table 6

[0083]

[0084] As can be seen from the table above, the cover plate structure provided in this comparison model has a large color difference, turning noticeably redder, and exhibits color variation at the curved edges.

[0085] Comparative Example 3

[0086] The film thickness at the curved edge is reduced by 10% compared to the flat portion, i.e., h1 / h2 = 1.11. The visible light wavelengths are λ1 = 400 nm, λ2 = 700 nm, and λ3 = 749 nm. The designed wavelength range for the coating is 400 nm to 749 nm. The reflectivity of the coating on the flat portion of the cover plate within the 400 nm to 749 nm range is ≤3%. The specific structure is as follows... Figure 2 As shown in Table 7.

[0087] Table 7

[0088]

[0089] Reflection curves of curved edge parts and planar parts, such as Figure 8 As shown in Table 8, the color difference test results are as follows.

[0090] Table 8

[0091]

[0092] As can be seen from the table above, the color difference of the cover plate structure provided in this comparison is too large. The color becomes more reddish where the film is thinner, and there is a phenomenon of different colors at the curved edge.

[0093] Example 2

[0094] Following the same design principles as in Example 1, a cover plate with seven coating layers was designed, with the specific structure as follows: Figure 3 As shown in Table 9.

[0095] Table 9

[0096]

[0097] Example 3

[0098] The film thickness at the curved edge is reduced by 76.7% compared to the flat portion, i.e., h1 / h2 = 4.29. The visible light wavelengths are λ1 = 400 nm, λ2 = 700 nm, and λ3 = 700 × 4.29 = 3003 nm. The designed wavelength range for the coating is 400 nm–3003 nm. The reflectivity of the coating on the flat portion of the cover plate within this range is ≤3%. The specific structure is as follows... Figure 4 As shown in Table 10.

[0099] Table 10

[0100]

[0101] This invention can reduce the film thickness of the curved edge portion by up to 76.7% relative to the flat portion within the design wavelength range of 400nm-3000nm, without causing color difference at the curved edge.

[0102] The preferred embodiments of this utility model have been described in detail above; however, this utility model is not limited thereto. Within the scope of the technical concept of this utility model, various simple modifications can be made to the technical solution of this utility model, including combining the various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed by this utility model and are all within the protection scope of this utility model.

Claims

1. A cover plate, characterized in that, The cover plate includes a transparent substrate and a coating layer deposited on the surface of the transparent substrate. The cover plate includes a planar portion (1) and a curved portion. The curved portion includes a curved middle portion (2) and a curved edge portion (3). The thickness of the coating layer in the planar part (1) is defined as h1, and the thickness of the coating layer in the curved edge part (3) is defined as h2. The units of h1 and h2 are the same, and h1 > h2. The minimum value of the visible light band is defined as λ1, and the maximum value of the visible light band is defined as λ2. The units of λ1 and λ2 are both nm. The reflectivity of the coating layer of the planar portion (1) of the cover plate is ≤3% in the range of light wavelength λ1~λ3, where λ3≥(λ2×h1 / h2).

2. The cover plate according to claim 1, characterized in that, The reflectivity of the coating layer on the planar portion (1) of the cover plate is ≤1% in the range of light wavelength λ1~λ3; The value of h1 / h2 is 1.0~4.

3.

3. The cover plate according to claim 2, characterized in that, The reflectivity of the coating layer on the planar portion (1) of the cover plate is ≤0.5% in the range of light wavelength λ1~λ3; The value of h1 / h2 is 1.0~2.

0.

4. The cover plate according to claim 1, characterized in that, λ3 = (λ2 × h1 / h2).

5. The cover plate according to claim 1, characterized in that, The coating layer comprises a first coating layer and a second coating layer from the inside out; the first coating layer is a medium refractive index layer, and the second coating layer comprises at least one high refractive index layer and at least one low refractive index layer stacked alternately in sequence; the outermost layer of the coating layer is a low refractive index layer.

6. The cover plate according to claim 5, characterized in that, The thickness of the coating layer is 200nm~600nm; The sum of the number of layers in the first coating layer and the second coating layer is 5 to 12.

7. The cover plate according to claim 5, characterized in that, The high refractive index layer has a refractive index of 1.9~2.2 and an extinction coefficient K<0.001; The refractive index of the material in the intermediate refractive index layer is 1.6~1.7, and the extinction coefficient K < 0.001; The low-refractive-index layer has a refractive index of 1.4 to 1.5 and an extinction coefficient K < 0.

001.

8. The cover plate according to claim 1, characterized in that, The cover plate has a reflectivity of 5% to 6% and a transmittance of 93% to 94%; the sum of the reflectivity and transmittance of the cover plate is >99%. And / or, the nanohardness of the coating layer of the cover plate is 8~10 GPa.

9. The cover plate according to any one of claims 1-8, characterized in that, The a value of the coating layer in the planar part (1) is defined as a1 and the b value as b1; the a value of the coating layer in the curved edge part (3) is defined as a2 and the b value as b2. |a2-a1|<0.8, |b2-b1|<2.

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