JP6402772B2 - Display cover member and manufacturing method thereof - Google Patents

Description

  The present invention relates to a display cover member and a manufacturing method thereof.

  Conventionally, in order to suppress regular reflection of light on the surface of the display, it has been proposed to arrange a cover member having an antiglare (AG) layer on the front surface of the display (see, for example, Patent Document 1).

JP 2013-504514 A

  From the viewpoint of suppressing regular reflection of light on the surface of the cover member, it is preferable to increase the surface roughness of the antiglare layer so that the haze of the cover member is increased. However, a display having a cover member with a large haze on the front surface has a problem that the resolution is lowered. Therefore, it is desired to realize high resolution while suppressing front reflection and suppressing reflection of the background.

  A main object of the present invention is to provide a display cover member that can realize a display having a high resolution with less reflection of a background.

In the cover member of the first display according to the present invention, one main surface is constituted by an uneven surface, and the average inclination angle (θ) of the roughness curve of the uneven surface is 0.5 ° to 1.5 °, Or, the average length (RSm) of the roughness curve element defined by JIS B0601-2013 on the uneven surface is 1.0 μm to 21.0 μm, and the area ratio in the bearing curve on the uneven curved surface of the uneven surface when but a height when 70% and _{H 1,} the height when the area ratio is 99% and _{H 2,} the arithmetic mean roughness defined by JIS B0601-2013 of the uneven surface was Ra (H ₁ -H ₂ ) / Ra is 0.25 or more.

In the cover member of the second display according to the present invention, one main surface is constituted by an uneven surface, and the average inclination angle (θ) of the roughness curve of the uneven surface and the roughness defined by JIS B0601-2013. The product (θ × RSm) of the average length (RSm) of the curved elements is 0.5 ° · μm to 40 ° · μm, and the area ratio is 70% in the bearing curve of the rough surface of the uneven surface. the height of a certain time and _{H 1,} the height when the area ratio is 99% and _{H 2,} the arithmetic mean roughness defined by JIS B0601-2013 of the uneven surface is taken as Ra, (H ₁ -H ₂₎ / Ra is 0.25 or more.

  The cover member of the first or second display according to the present invention preferably has a haze of 0.5% or more and less than 10%. The cover member of the first or second display according to the present invention includes a translucent plate and a coating film that covers at least part of one main surface of the translucent plate and forms an uneven surface. Is preferred.

  In the cover member of the first or second display according to the present invention, it is preferable that the coating film covers the entire main surface of the light-transmitting plate.

  As for the cover member of the 1st or 2nd display which concerns on this invention, it is preferable that the coating film is comprised with the inorganic film.

  As for the cover member of the 1st or 2nd display which concerns on this invention, it is preferable that the pencil hardness of a coating film is 6H or more.

  As for the cover member of the 1st or 2nd display which concerns on this invention, it is preferable that the translucent board is comprised with the tempered glass board.

  The manufacturing method of the display cover member according to the present invention is a method for manufacturing the cover member of the first or second display. In the method for manufacturing a cover member for a display according to the present invention, it is preferable to form a coating film constituting an uneven surface by a spray method on a light transmitting plate.

  In the manufacturing method of the cover member of the display which concerns on this invention, it is preferable to chemically strengthen a glass plate, after comprising a translucent plate with a glass plate and forming a coating film.

  In the manufacturing method of the cover member of the display which concerns on this invention, it is preferable to use a tempered glass board as a translucent board.

  ADVANTAGE OF THE INVENTION According to this invention, the cover member of a display which can implement | achieve the display with few reflections of a background and high resolution can be provided.

FIG. 1 is a schematic cross-sectional view of a cover member of a display according to an embodiment of the present invention. FIG. 2 is a roughness curve and bearing curve plot of the uneven surface of the cover member manufactured in Example 1. FIG. 3 is a roughness curve and bearing curve plot of the uneven surface of the cover member manufactured in Example 2. FIG. 4 is a roughness curve and bearing curve plot of the uneven surface of the cover member manufactured in Example 3. FIG. 5 is a roughness curve and bearing curve plot of the uneven surface of the cover member manufactured in Example 4. 6 is a roughness curve and bearing curve plot of the uneven surface of the cover member manufactured in Comparative Example 1. FIG. FIG. 7 is a roughness curve and a bearing curve plot of the uneven surface of the cover member manufactured in Comparative Example 2. 8 is a roughness curve and bearing curve plot of the uneven surface of the cover member manufactured in Comparative Example 3. FIG. FIG. 9 is a perspective view illustrating the shape of the uneven surface of the cover member manufactured in Example 1. FIG. FIG. 10 is a perspective view illustrating the shape of the uneven surface of the cover member manufactured in Example 2. FIG. FIG. 11 is a perspective view showing the shape of the uneven surface of the cover member manufactured in Example 3. FIG. 12 is a perspective view showing the shape of the uneven surface of the cover member manufactured in Comparative Example 1. FIG. 13 is a perspective view showing the shape of the uneven surface of the cover member manufactured in Comparative Example 2. FIG. 14 is a perspective view showing the shape of the uneven surface of the cover member manufactured in Comparative Example 3. FIG.

  Hereinafter, an example of the preferable form which implemented this invention is demonstrated. However, the following embodiment is merely an example. The present invention is not limited to the following embodiments.

  FIG. 1 is a schematic cross-sectional view of a cover member 1 of a display according to this embodiment. The cover member 1 is a member used by being disposed on the front surface of the display. Specifically, the cover member 1 is provided and used in a display such that the first main surface 1a faces the outside (viewer side) and the second main surface 1b faces the inside. For example, the cover member 1 may be a member constituting a front plate of the display, or a member provided on the front plate.

  The first main surface 1 a of the cover member 1 is constituted by an uneven surface 2.

  Specifically, in the present embodiment, the cover member 1 includes a translucent plate 10 and a coating film 11. But in this invention, the cover member may be comprised by one member.

The translucent plate 10 is not particularly limited as long as it transmits light from the display. The translucent plate 10 may be composed of, for example, a glass plate such as alkali-free glass or soda lime glass, a crystallized glass plate such as Li ₂ O—Al ₂ O ₃ —SiO ₂ based crystallized glass, a resin plate, or the like. it can. For example, when high mechanical strength is required for the cover member 1, it is preferable that the translucent plate 10 is made of a tempered glass plate.

  The thickness of the translucent plate 10 is not particularly limited. The thickness of the translucent plate 10 can be set to about 0.03 mm to 10 mm, for example. The translucent plate 10 may be a rigid body, but may have flexibility. The translucent plate 10 may be in the form of a sheet.

Incidentally, tempered glass plate is preferably used as the light transmitting plate 10, as a glass composition, in _{mass%, SiO 2 50~80%, Al} 2 O 3 5~25%, B 2 O 3 0~15%, Na ₂ O 1 to _20%, preferably contains K 2 O 0~10%. The reason for limiting the content range of each component as described above will be described below.

SiO ₂ is a component that forms a network of glass. The content of SiO ₂ is preferably 50-80%, 52-75%, 55-72%, 55-70%, in particular 55-67.5%. If the content of SiO ₂ is too small, vitrification becomes difficult, and the thermal expansion coefficient becomes too high, so that the thermal shock resistance tends to decrease. On the other hand, if the content of SiO ₂ is too large, the meltability and the formability tends to decrease.

Al ₂ O ₃ is a component that improves ion exchange performance, and is a component that increases the strain point and Young's modulus. The content of Al ₂ O ₃ is preferably 5 to 25%. If the content of Al ₂ O ₃ is too small, the thermal expansion coefficient becomes too high and the thermal shock resistance tends to be lowered, and there is a possibility that the ion exchange performance cannot be sufficiently exhibited. Therefore, the preferable lower limit range of Al ₂ O ₃ is 7% or more, 8% or more, 10% or more, 12% or more, 14% or more, 15% or more, particularly 16% or more. On the other hand, when the content of Al ₂ O ₃ is too large, devitrification crystal glass becomes easy to precipitate, and it becomes difficult to mold the glass sheet by an overflow down draw method or the like. In addition, the thermal expansion coefficient becomes too low to make it difficult to match the thermal expansion coefficient of the surrounding material, and further, the high-temperature viscosity becomes high and the meltability tends to be lowered. Therefore, the preferable upper limit range of Al ₂ O ₃ is 22% or less, 20% or less, 19% or less, 18% or less, particularly 17% or less.

B ₂ O ₃ is a component that lowers the high temperature viscosity and density, stabilizes the glass, makes it difficult to precipitate crystals, and lowers the liquidus temperature. It is also a component that increases crack resistance. However, if the content of B ₂ O ₃ is too large, the ion exchange treatment may cause coloring of the surface called burnt, decrease in water resistance, decrease in the compressive stress value of the compressive stress layer, The stress depth of the stress layer tends to decrease. Therefore, the content of B ₂ O ₃ is preferably 0 to 15%, 0.1 to 12%, 1 to 10%, more than 1 to 8%, 1.5 to 6%, particularly 2 to 5%. .

Na ₂ O is a main ion exchange component, and is a component that lowers the high temperature viscosity and improves the meltability and moldability. Na ₂ O is also a component that improves devitrification resistance. The content of Na ₂ O is 1 to 20%. When Na 2 _O content is too small, or reduced meltability, lowered coefficient of thermal expansion tends to decrease the ion exchange performance. Therefore, when Na ₂ O is introduced, a preferable lower limit range of Na ₂ O is 10% or more, 11% or more, and particularly 12% or more. On the other hand, when the content of Na ₂ O is too large, the thermal expansion coefficient becomes too high, the thermal shock resistance is lowered, and it becomes difficult to match the thermal expansion coefficient of the surrounding materials. In addition, the strain point may be excessively lowered or the component balance of the glass composition may be lost, and the devitrification resistance may be deteriorated. Therefore, a preferable upper limit range of Na ₂ O is 17% or less, particularly 16% or less.

K ₂ O is a component that promotes ion exchange, and is a component that has a large effect of increasing the stress depth of the compressive stress layer among alkali metal oxides. Moreover, it is a component which reduces high temperature viscosity and improves a meltability and a moldability. Furthermore, it is also a component that improves devitrification resistance. The content of K ₂ O is 0 to 10%. When the content of K 2 _O is too large, the thermal expansion coefficient becomes too high, the thermal shock resistance becomes difficult to match or decreased, the thermal expansion coefficient with those of peripheral materials. Moreover, there is a tendency that the strain point is excessively lowered, the component balance of the glass composition is lacking, and the devitrification resistance is lowered. Therefore, the preferable upper limit range of K ₂ O is 8% or less, 6% or less, 4% or less, and particularly less than 2%.

  In addition to the above components, for example, the following components may be introduced.

Li ₂ O is an ion exchange component and a component that lowers the high-temperature viscosity and improves the meltability and moldability. It is also a component that increases Young's modulus. Furthermore, the effect of increasing the compressive stress value is large among alkali metal oxides. However, when the content of Li 2 _O is too large, and decreases the liquidus viscosity, it tends glass devitrified. In addition, the thermal expansion coefficient becomes too high, so that the thermal shock resistance is lowered or it is difficult to match the thermal expansion coefficient of the surrounding material. Furthermore, if the low-temperature viscosity is too low and stress relaxation is likely to occur, the compressive stress value may be reduced. Therefore, the content of Li ₂ O is preferably 0 to 3.5%, 0 to 2%, 0 to 1%, 0 to 0.5%, particularly 0.01 to 0.2%.

The preferred content of Li ₂ O + Na ₂ O + K ₂ O is 5-25%, 10-22%, 15-22%, especially 17-22%. When _{Li 2 O + Na 2 O +} K content of ₂ O is too small, the ion exchange performance and meltability is liable to decrease. On the other hand, if the content of Li ₂ O + Na ₂ O + K ₂ O is too large, the glass tends to be devitrified, the thermal expansion coefficient becomes too high, the thermal shock resistance decreases, and the heat of the surrounding materials It becomes difficult to match the expansion coefficient. In addition, the strain point may be excessively lowered, making it difficult to obtain a high compressive stress value. Furthermore, the viscosity in the vicinity of the liquidus temperature may decrease, making it difficult to ensure a high liquidus viscosity. “Li ₂ O + Na ₂ O + K ₂ O” is the total amount of Li ₂ O, Na ₂ O and K ₂ O.

  MgO is a component that lowers the viscosity at high temperature, increases meltability and moldability, and increases the strain point and Young's modulus. Among alkaline earth metal oxides, MgO is a component that has a large effect of improving ion exchange performance. is there. However, when there is too much content of MgO, a density and a thermal expansion coefficient will become high easily, and it will become easy to devitrify glass. Therefore, the preferable upper limit range of MgO is 12% or less, 10% or less, 8% or less, 5% or less, and particularly 4% or less. In addition, when introducing MgO into a glass composition, the suitable minimum range of MgO is 0.1% or more, 0.5% or more, 1% or more, especially 2% or more.

  Compared with other components, CaO has a large effect of lowering the high temperature viscosity and improving the meltability and moldability, and increasing the strain point and Young's modulus without deteriorating devitrification resistance. The content of CaO is preferably 0 to 10%. However, when there is too much content of CaO, a density and a thermal expansion coefficient will become high, the component balance of a glass composition will be missing, and it will become easy to devitrify glass on the contrary, or ion exchange performance will fall easily. Therefore, suitable content of CaO is 0 to 5%, 0.01 to 4%, 0.1 to 3%, particularly 1 to 2.5%.

  SrO is a component that lowers the high-temperature viscosity without increasing devitrification resistance, thereby increasing the meltability and moldability, and increasing the strain point and Young's modulus. However, when the content of SrO is too large, the density and thermal expansion coefficient are increased, the ion exchange performance is lowered, and the glass composition tends to be devitrified due to lack of the component balance of the glass composition. A suitable content range of SrO is 0 to 5%, 0 to 3%, 0 to 1%, particularly 0 to less than 0.1%.

  BaO is a component that lowers the high-temperature viscosity without increasing devitrification resistance, thereby improving the meltability and moldability, and increasing the strain point and Young's modulus. However, when there is too much content of BaO, a density and a thermal expansion coefficient will become high, an ion exchange performance will fall, or it lacks the component balance of a glass composition, and on the contrary, it becomes easy to devitrify glass. A suitable content range of BaO is 0 to 5%, 0 to 3%, 0 to 1%, particularly 0 to less than 0.1%.

  ZnO is a component that enhances the ion exchange performance, and is a component that is particularly effective in increasing the compressive stress value. Moreover, it is a component which reduces high temperature viscosity, without reducing low temperature viscosity. However, when the content of ZnO is too large, the glass tends to undergo phase separation, the devitrification resistance decreases, the density increases, and the stress depth of the compressive stress layer decreases. Therefore, the content of ZnO is preferably 0 to 6%, 0 to 5%, 0 to 1%, 0 to 0.5%, particularly preferably 0 to less than 0.1%.

ZrO ₂ is a component that remarkably improves the ion exchange performance, and is a component that increases the viscosity and strain point near the liquid phase viscosity. However, if its content is too large, the devitrification resistance may be significantly reduced. There is also a possibility that the density becomes too high. Therefore, the preferable upper limit range of ZrO ₂ is 10% or less, 8% or less, 6% or less, particularly 5% or less. In addition, when it is desired to improve the ion exchange performance, it is preferable to introduce ZrO ₂ into the glass composition. In this case, the suitable lower limit range of ZrO ₂ is 0.001% or more, 0.01% or more, 0.5% In particular, it is 1% or more.

P ₂ O ₅ is a component that enhances ion exchange performance, and in particular, a component that increases the stress depth of the compressive stress layer. However, when the content of P ₂ O ₅ is too large, easily glass phase separation. Therefore, the preferable upper limit range of P ₂ O ₅ is 10% or less, 8% or less, 6% or less, 4% or less, 2% or less, 1% or less, particularly less than 0.1%.

As a fining agent, one or two or more selected from the group of As ₂ O ₃ , Sb ₂ O ₃ , SnO ₂ , F, Cl, and SO ₃ (preferably a group of SnO ₂ , Cl, and SO ₃ ) 30,000 ppm (3%) may be introduced. The content of SnO ₂ + SO ₃ + Cl is preferably 0 to 10000 ppm, 50 to 5000 ppm, 80 to 4000 ppm, 100 to 3000 ppm, particularly 300 to 3000 ppm, from the viewpoint of accurately enjoying the clarification effect. Here, “SnO ₂ + SO ₃ + Cl” refers to the total amount of SnO ₂ , SO ₃ and Cl.

The preferred content range of SnO ₂ is 0 to 10000 ppm, 0 to 7000 ppm, especially 50 to 6000 ppm. The preferred content range of Cl is 0 to 1500 ppm, 0 to 1200 ppm, 0 to 800 ppm, 0 to 500 ppm, especially 50 to 300 ppm. It is. A suitable content range of SO ₃ is 0 to 1000 ppm, 0 to 800 ppm, particularly 10 to 500 ppm.

Rare earth oxides such as Nd ₂ O ₃ and La ₂ O ₃ are components that increase the Young's modulus, and are components that can be decolored to control the color of glass when a complementary color is added. However, the cost of the raw material itself is high, and if it is introduced in a large amount, the devitrification resistance tends to decrease. Therefore, the rare earth oxide content is preferably 4% or less, 3% or less, 2% or less, 1% or less, particularly 0.5% or less.

In the present invention, in consideration of environmental, substantially _{As 2 O 3, F, PbO} , preferably contains no _Bi 2 _{O 3.} Here, “substantially does not contain As ₂ O ₃ ” means that the glass component does not positively add As ₂ O ₃ but allows mixing at the impurity level. This means that the content of As ₂ O ₃ is less than 500 ppm. “Substantially free of F” means that F is not actively added as a glass component but is allowed to be mixed at an impurity level. Specifically, the content of F is less than 500 ppm. It points to something. “Substantially no PbO” means that although PbO is not actively added as a glass component, it is allowed to be mixed at an impurity level. Specifically, the PbO content is less than 500 ppm. It points to something. By "substantially free of Bi ₂ O _3", but not added actively Bi ₂ O ₃ as a glass component, a purpose to allow the case to be mixed with impurity levels, specifically, Bi ₂ It indicates that the content of O ₃ is less than 500 ppm.

  The translucent plate 10 has a first main surface 10a and a second main surface 10b. In the present embodiment, each of the first and second main surfaces 10a and 10b is a flat surface. The second main surface 1 b of the cover member 1 is constituted by the second main surface 10 b of the light transmitting plate 10. A coating film 11 is provided on the first main surface 10 a of the light transmitting plate 10. The coating film 11 covers at least a part of the first main surface 10 a constituting the uneven surface 2. For example, the coating film 11 may cover the entire first main surface 10a or may cover a part of the first main surface 10a. The coating film 11 may be provided in an island shape, for example. When the coating film 11 covers a part of the first main surface 10a, the first main surface 1a of the cover member 1 is constituted by the coating film 11 and the first main surface 1a.

  When the cover member 1 is used for a touch sensor or the like, for example, the surface of the cover member 1 is required to have high durability (such as scratch resistance). For this reason, it is preferable that the coating film 11 is hard. The pencil hardness of the coating film 11 is preferably 6H or more, more preferably 7H or more, further preferably 8H or more, and still more preferably 9H or more.

The coating film 11 can be composed of an inorganic film made of an inorganic oxide such as SiO ₂ , TiO ₂ , Al ₂ O ₃ , or ZrO ₂ . Of these, the coating film 11 is preferably made of SiO _2.

  The thickness of the coating film 11 is preferably 0.1 μm to 5 μm, for example.

  In the present embodiment, an example in which the coating film 11 is directly provided on the first main surface 10a of the translucent plate 10 will be described. However, the present invention is not limited to this configuration. For example, an antireflection film or the like may be provided between the coating film and the translucent plate. Further, an antireflection film, a transparent conductive film, or the like may be provided also on the second main surface 10b of the translucent plate.

  The antireflection film is, for example, a low refractive index film having a lower refractive index than that of the translucent plate 10, a low refractive index layer having a relatively low refractive index, and a high refractive index layer having a relatively high refractive index. It may be a dielectric multilayer film laminated on the substrate. The antireflection film can be formed by, for example, a sputtering method or a CVD method.

  The transparent conductive film functions as an electrode for a touch sensor when the translucent plate 10 is used as a cover glass. Examples of the transparent conductive film include a tin-doped indium oxide (ITO) film, a fluorine-doped tin oxide (FTO) film, and an antimony-doped tin oxide (ATO) film. Among these, an ITO film is preferably used because of its low electric resistance. The ITO film can be formed by, for example, a sputtering method. Further, the FTO film and the ATO film can be formed by a CVD (Chemical Vapor Deposition) method.

  In the present embodiment, the coating film 11 constitutes the surface of the cover member 1. However, the present invention is not limited to this configuration. On the coating film, for example, another film such as an anti-fingerprint film (AF film) or an antireflection film may be further provided to prevent adhesion of fingerprints and impart water repellency and oil repellency. .

  The AF film preferably contains a fluoropolymer containing silicon in the main chain. Examples of the fluorinated polymer include a polymer having a —Si—O—Si— unit in the main chain and a water-repellent functional group containing fluorine in the side chain. The fluorine-containing polymer can be synthesized, for example, by dehydrating condensation of silanol.

  When the antireflection film and the AF film are formed on the uneven surface side of the light transmitting plate 10, the antireflection film may be formed on the uneven surface, and the AF film may be formed on the antireflection film. preferable.

  As described above, it is preferable to increase the haze of the cover member from the viewpoint of suppressing regular reflection of light on the surface of the cover member. However, a display having a cover member with a large haze on the front surface has a problem that the resolution is lowered. That is, it is impossible to achieve both high resolution and suppression of background reflection only by adjusting the haze.

  As a result of intensive studies, the inventors have obtained the following conditions (A) and (C) or conditions (B) and (C) even when the haze is reduced to some extent in order to obtain high resolution. It has been conceived that the reflection of the background can be suppressed by satisfying the following conditions or by satisfying the following conditions (C) and (D).

Condition (A): The average inclination angle (θ) of the roughness curve of the uneven surface is 0.5 ° to 1.5 °.
Condition (B): The average length (RSm) of the roughness curve element defined by JIS B0601-2013 on the uneven surface is 1.0 μm to 21.0 μm.
Condition (C): (H ₁ -H ₂ ) /Ra≧0.25
Condition (D): The product θ × RSm of the average inclination angle (θ) of the roughness curve of the uneven surface and the average length (RSm) of the roughness curve element defined by JIS B0601-2013 of the uneven surface is 0.5 ~ 40 ° ・ μm

However,
H ₁ : Height when the area ratio is 70% in the bearing curve of the roughness curved surface of the uneven surface 2,
H ₂ : Height when the area ratio is 99% in the bearing curve of the roughness curved surface of the uneven surface 2,
Ra: Arithmetic average roughness defined by JIS B0601-2013 on the uneven surface.

  A bearing curve is a graph created by a bearing curve plotting method, which is a technique for analyzing the height distribution of a surface with a rough surface. The bearing curve plot shows the area ratio that changes when the position (height component) of the cutting plane parallel to the center plane is changed in the part extracted by the reference area from the curved surface represented by the surface roughness data. (Ratio with respect to the reference | standard area of the total cross-sectional area of the mountain cut | disconnected by the said cutting plane) is represented with a graph. In the bearing curve, the vertical axis is the area ratio (integrated value) (%), and the horizontal axis is the height (nm). For example, at the point where the (height, area ratio) of the bearing curve is (Hnm, S%), the ratio of the area of the region having a height of Hnm or more to the total area of the uneven surface ((the height is The area of the area equal to or higher than H / (the entire area of the uneven surface)) is S%.

Therefore, in the cover member 1, the average inclination angle (θ) of the roughness curve of the concavo-convex surface 2 is set to 0.5 ° to 1.5 °, and (H ₁ −H ₂ ) / Ra is 0. It is set to 25 or more. Therefore, by using the cover member 1, it is possible to realize a display having a high resolution with less reflection of the background. Hereinafter, this effect will be described in more detail.

In this embodiment, the average inclination angle (θ) of the roughness curve of the uneven surface 2 is set to 0.5 ° to 1.5 ° (condition (A)). For this reason, the uneven surface 2 is constituted by gentle unevenness. In addition, (H ₁ -H ₂ ) / Ra is set to 0.25 or more (condition (C)). Here, (H ₁ −H ₂ ) / Ra can be considered as an index of the area ratio of the flat surface in the valley of the uneven surface 2. (H ₁ −H ₂ ) / Ra decreases as the number of flat portions in the valley portion of the uneven surface 2 decreases, and conversely, as the number of flat portions in the valley portion of the uneven surface 2 decreases, (H ₁ −H ₂ ) / Ra increases. For this reason, the ratio of the area | region parallel to the 1st main surface 10a which occupies the trough part of the uneven surface 2 is small. Therefore, although the transmitted light is difficult to diffuse, regular reflection hardly occurs. Therefore, by using the cover member 1, it is possible to realize a display having a high resolution with less reflection of the background.

For example, when the haze is constant, the unevenness constituting the uneven surface becomes closer to flat as the average inclination angle θ decreases, and the proportion of the region parallel to the first main surface 10a in the uneven surface tends to increase. . Similarly, as (H ₁ −H ₂ ) / Ra is smaller, the ratio of the region parallel to the first main surface 10 a in the valleys of the uneven surface tends to increase. Therefore, when the average inclination angle θ is large or (H ₁ −H ₂ ) / Ra is small, regular reflection tends to occur and the background is easily reflected.

  Similarly, when the first main surface 10a is exposed, the background is easily reflected. For this reason, it is preferable that the coating film 11 covers the entire first main surface 10a. For example, when the coating film 11 has an island shape, the exposure rate of the first main surface 10a is increased. For this reason, it is preferable that the coating film 11 is not island-shaped.

  By satisfying the condition (B) (the average length (RSm) of the roughness curve element defined by JIS B0601-2013 of the uneven surface is 1.0 μm to 21.0 μm), excellent scratch resistance and High resolution can be achieved at the same time. If the average length (RSm) of the roughness curve element is too small, surface durability (abrasion resistance) may be reduced. If the average length (RSm) of the roughness curve element is too large, the resolution may decrease.

  Condition (D) (the product θ × RSm of the average inclination angle (θ) of the roughness curve of the uneven surface and the average length (RSm) of the roughness curve element defined by JIS B0601-2013 of the uneven surface is 0.5 By satisfying (˜40 ° · μm), high resolution can be obtained while suppressing reflection. If the product θ × RSm is too small, the reflection may become conspicuous. If the product θ × RSm is too large, the resolution may decrease.

  In addition, from the viewpoint of setting the conditions (A), the conditions (B), and the conditions (D) related to θ and RSm in a preferable range, at least a part of one main surface of the translucent plate 10 is covered, and an uneven surface is formed. The coating film 11 is preferably provided.

  The coating film 11 does not contain scattering particles like a fine particle dispersion film, and is preferably a homogeneous film. In this case, the resolution can be further increased and the reflection can be more effectively suppressed.

  The coating film 11 preferably has a lower refractive index than the translucent plate 10. In that case, reflection can be more effectively suppressed.

  From the viewpoint of more effectively realizing a display having a high resolution, the average inclination angle θ is preferably 0.9 ° or less, and more preferably 0.8 ° or less.

From the viewpoint of more effectively suppressing the reflection of the background, (H ₁ -H ₂ ) / Ra is more preferably 0.45 or more, and further preferably 0.5 or more.

  From the viewpoint of more effectively realizing a display having a high resolution, the average length (RSm) of the roughness curve element is preferably 20.0 μm or less, and more preferably 18.0 μm or less.

  From the viewpoint of more effectively realizing a display having a high resolution, the product θ × RSm is preferably 39 ° · μm or less, and more preferably 38 ° · μm or less.

  In the present invention, the average inclination angle θ can be specifically measured as follows, for example.

  Measuring method of average inclination angle θ: The average inclination angle θ is defined by the following mathematical formula (1).

Average inclination angle θ = tan ⁻¹ Δa (1) In Equation (1), Δa is the reference length of the roughness curve defined in JIS B 0601-2013 as shown in Equation (2) below. In l, the sum of the absolute values (h1 + h2 + h3... + hn) of the difference (height h) between the apex of adjacent peaks and the lowest point of the valley is a value obtained by dividing by the reference length l.

  Δa = (h1 + h2 + h3... + Hn) / l (2) Specifically, the average inclination angle can be measured as follows.

  The height of the surface of the concavo-convex surface 2 is measured along one direction by scanning the surface of the concavo-convex surface 2 with a laser or a stylus along one direction. The length (measurement length) along one direction in which the height measurement is performed can be set to about 200 μm to 350 μm, for example. The height can be measured at intervals of 0.5 μm, for example.

  Next, the center line L is determined. Specifically, the center line L that passes through the average height of the uneven surface is determined.

  Next, the absolute value of the angle between the irregular surface 2 and the center line L is measured every 0.5 μm interval. Then, the average inclination angle θ can be calculated by averaging the absolute values of the angles formed by the concavo-convex surface 2 and the center line L every 0.5 μm interval measured every 0.5 μm interval. it can.

  Haze is the ratio of diffusely transmitted light to total light transmitted. For this reason, diffuse transmitted light can be reduced by reducing the haze. Therefore, high resolution can be realized. The haze of the cover member 1 is preferably less than 10%, more preferably less than 4%, more preferably 3% or less, and even more preferably 2% or less. However, if the haze of the cover member 1 is too small, the background may be easily reflected. Therefore, the haze of the cover member 1 is preferably 0.5% or more, and more preferably 0.8% or more.

  Next, an example of a method for manufacturing the cover member 1 will be described.

  First, the translucent plate 10 is prepared. Next, the coating film 11 can be formed by applying a light-transmitting material on the first main surface 10a of the light-transmitting plate 10 by a spray method and drying it. By forming the coating film 11 using the spray method, it becomes easy to set the conditions (A), (B), and (D) regarding θ and RSm within a preferable range.

  More specifically, the coating film 11 can be formed as follows. While the translucent plate 10 is transported through the coating chamber, the translucent material is ejected from the nozzle toward the translucent plate 10 while reciprocating the nozzle in a direction perpendicular to the transport direction of the translucent plate 10. I will do it. Then, the coating film 11 can be completed by drying the obtained coating film. During film formation, it is preferable to apply a laminar flow that flows downward from above to the coating chamber.

The average inclination angle θ and (H ₁ −H ₂ ) / Ra of the cover member 1 to be manufactured are, for example, the particle size of the liquid droplets discharged from the nozzle, the discharge pressure, the amount discharged per unit area, and the laminar flow rate. It can be adjusted by controlling etc.

For example, the average inclination angle θ can be reduced and (H ₁ −H ₂ ) / Ra can be increased by reducing the particle size of the droplets ejected from the nozzle. Moreover, the average length (RSm) of the roughness curve element can be reduced. The particle diameter of the droplets discharged from the nozzle is preferably 20 μm or less, and more preferably 10 μm or less.

For example, by increasing the discharge pressure from the nozzle, the average inclination angle θ can be reduced, and (H ₁ −H ₂ ) / Ra can be increased. For example, the discharge pressure from the nozzle is preferably 0.25 MPa or more, and more preferably 0.3 MPa or more.

  By reducing the discharge pressure from the nozzle, the average length (RSm) of the roughness curve element can be reduced. From this viewpoint, the discharge pressure from the nozzle is preferably 0.34 MPa or less.

For example, by reducing the coating amount per unit area, the average inclination angle θ can be reduced, and (H ₁ −H ₂ ) / Ra can be increased. For example, the coating amount per unit area is preferably 50 g / m ² or less, and more preferably 48 g / m ² or less.

For example, by increasing the laminar flow rate, the average inclination angle θ can be reduced, and (H ₁ −H ₂ ) / Ra can be increased. The laminar flow rate is preferably, for example, 25 m ³ / min or more.

  When the translucent plate 10 is composed of a tempered glass plate, the coating film 11 may be formed on the tempered glass plate, or after the coating film 11 is formed on the glass plate, the glass plate May be strengthened by chemical strengthening or air cooling strengthening.

  Hereinafter, the present invention will be described in more detail on the basis of specific examples. However, the present invention is not limited to the following examples, and may be appropriately modified and implemented without departing from the scope of the present invention. Is possible.

(Examples 1 to 3 and Comparative Example 1) On a glass flat plate (Non-alkali glass flat plate manufactured by Nippon Electric Glass Co., Ltd., thickness 0.7 mm), a liquid containing a SiO ₂ component is applied by a spray method and dried. Thus, a coating film was formed and a cover member was obtained. Detailed conditions are shown in Table 1.

(Example 4) On a glass flat plate (tempered glass flat plate made by Nippon Electric Glass Co., Ltd., thickness 0.7 mm), a coating film is formed by applying a liquid containing SiO ₂ component by a spray method and drying. A cover member was obtained. Detailed conditions are shown in Table 1.

  (Comparative Examples 2 and 3) An uneven surface was formed by etching one principal surface of a glass flat plate (Non-alkali glass flat plate manufactured by Nippon Electric Glass Co., Ltd., thickness 0.7 mm) to obtain a cover member.

  (Measurement of haze) Based on JISK7136 (2000), the haze of the cover member produced in Examples 1-4 and Comparative Examples 1-3 was measured. The results are shown in Table 1.

The measurement method of (the average inclination angle theta and (H 1 _-H 2) / _Ra measurements) the average inclination angle theta, the average inclination angle theta of the cover member manufactured in Examples 1-4 and Comparative Examples 1-3 Asked. In this measurement, the reference length was 317 μm. Further, (H ₁ -H ₂ ) / Ra was determined from the surface roughness curved surface in the range of 317 μm × 238 μm by the bearing curve plotting method. The results are shown in Table 1. Moreover, the roughness curve and bearing curve plot of the measured uneven surface are shown in FIGS. The perspective view of the uneven surface of each cover member is shown in FIGS.

  (Evaluation of resolution) A cover member is installed above the letter “c” having a line thickness of 1 mm, a height of 4 mm, and a width of 4 mm, at a height of 20 mm, and the letter “c” is visually observed from a position 500 mm away. Was observed. At that time, the case where the character “c” was clearly visible was judged as “◎”, the case where the character “c” was clearly visible was ○, the case where the character “c” was slightly blurred was judged as “◯”, the case where the character “c” was blurry could be judged as Δ.

  (Evaluation of the degree of reflection) A mending tape (manufactured by 3M) was attached to the back surface of the cover member, and the fluorescent lamp was reflected on the uneven surface of the cover member. Judgment that the reflected fluorescent light is blurred and not visible at all, ◎ when it is slightly visible, ◯ when it is blurred, △ when the fluorescent light is visible but slightly blurred, and X when the fluorescent light is clearly visible went.

From the results shown in Table 1, even if the haze is reduced to some extent, the following condition (A) or condition (B) and condition (C) should be satisfied, or the following condition: It can be seen that, by satisfying the condition (C) and the condition (D), the reflection of the background can be suppressed while realizing a high resolution.

1: cover member 1a: first main surface 1b: second main surface 2: uneven surface 10: translucent plate 10a: first main surface 10b: second main surface 11: coating film

Claims (11)

One main surface is composed of an uneven surface,
The average inclination angle (θ) of the roughness curve of the uneven surface is 0.5 ° to 1.5 °, or the average length (RSm) of the roughness curve element defined by JIS B0601-2013 of the uneven surface. Is 1.0 μm to 21.0 μm, and in the bearing curve of the roughness curved surface of the uneven surface, the height when the area ratio is 70% is H ₁ and the area ratio is 99%. A cover for a display, wherein (H ₁ −H ₂ ) / Ra is 0.25 or more, where H ₂ is the height and Ra is the arithmetic average roughness defined by JIS B0601-2013 of the uneven surface. Element. One main surface is composed of an uneven surface,
The product (θ × RSm) of the average inclination angle (θ) of the roughness curve of the uneven surface and the average length (RSm) of the roughness curve element defined by JIS B0601-2013 is 0.5 ° · μm to 40 ° · a [mu] m, and, in the bearing curve of the roughness curved surface of the irregular surface, the height when the area ratio is 70% and H _1, the height when the area ratio is 99% H ₂ And (H ₁ −H ₂ ) / Ra is 0.25 or more, where Ra is the arithmetic average roughness defined by JIS B0601-2013 of the uneven surface.   The display cover member according to claim 1, wherein the haze is 0.5% or more and less than 10%. A translucent plate,
A coating film that covers at least a part of one principal surface of the translucent plate and forms the uneven surface;
The display cover member according to claim 1, comprising:   The display cover member according to claim 4, wherein the coating film covers an entire main surface of the translucent plate.   The display cover member according to claim 4, wherein the coating film is made of an inorganic film.   The display cover member according to any one of claims 4 to 6, wherein the coating film has a pencil hardness of 6H or more.   The display cover member according to any one of claims 4 to 7, wherein the translucent plate is formed of a tempered glass plate. A method for manufacturing a cover member for a display according to claim 1,
A method for producing a cover member for a display, comprising forming a coating film constituting the uneven surface on a light-transmitting plate by a spray method. The translucent plate is composed of a glass plate,
The method for manufacturing a display cover member according to claim 9, wherein the glass plate is chemically strengthened after the coating film is formed. The manufacturing method of the cover member of the display of Claim 9 which uses a tempered glass board as said translucent board.