JP6372590B2 - Cover member and portable information device - Google Patents

Description

  The present invention relates to a cover member and a portable information device.

Conventionally, in order to improve visibility such as time display, it is known to form an antireflection layer on a translucent member called a cover glass (windshield). This antireflection layer is generally constructed by laminating several to several tens of inorganic layers having different refractive indexes. When high hardness and scratch resistance are required on the surface of the cover glass, In many cases, SiO ₂ having high transmittance, low refractive index and relatively high hardness is formed on the outermost layer of the antireflection layer. For example, a technique for forming an antireflection layer in which SiO ₂ is the outermost layer and the lowermost layer and SiO ₂ films and Si ₃ N ₄ films are alternately laminated is disclosed on the surface of a watch cover glass (patent) Reference 1). Further, a watch windshield glass having silicon oxide (SiO ₂ ) as the outermost layer and a silicon nitride film formed on the surface of the watch cover glass is also disclosed (see Patent Document 2).

JP 2004-271480 A JP 2006-275526 A

By the way, the conventional wristwatch provided with the antireflection layer in which the SiO ₂ film and the Si ₃ N ₄ film are alternately laminated often has a deep scratch on the surface of the cover glass when used for daily life. However, the reason for this is not always clear, and it is unclear how the lamination of films with different hardness, such as SiO ₂ and Si ₃ N ₄ films, affects the hardness and scratch resistance of the cover glass surface. It was. Therefore, the antireflection optical simulation in the cover glass has been performed without considering the thickness ratio between the SiO ₂ film and the Si ₃ N ₄ film.

  Accordingly, an object of the present invention is to provide a cover member having an antireflection function and having a sufficiently high hardness and ensuring scratch resistance, and a mobile phone including the cover member.

As a result of studying the scratch resistance of the antireflection layer, we have found that the average hardness in the range of 150 nm from the outermost surface greatly affects the scratch resistance. Specifically, evaluation of hardness, scratch resistance, and optical characteristics was repeatedly performed while changing the thicknesses of the relatively soft SiO ₂ film and the hard Si ₃ N ₄ film. As a result, it was found that from the outermost surface of the antireflection layer to 150 nm, the scratch resistance increases as the hardness increases, but the increase in hardness at a position deeper than 150 nm does not significantly affect the scratch resistance. The ratio of _{the Si} 3 _{N 4} film in a range from the outermost surface of 150nm of the antireflection layer has been found that when 30～50Vol%, there is a condition that can achieve both high scratch resistance and low reflectivity.

The present invention is a translucent member comprising a substrate having translucency, wherein at least part of the surface of the substrate has a high refractive index layer made of silicon nitride and a low refractive index made of silicon oxide. An antireflection layer formed by alternately laminating layers is formed, and the antireflection layer has a silicon nitride content of 30 to 50 vol% in a range from the outermost surface to a depth of 150 nm. .
Here, examples of the translucent member include a hard and transparent member such as a watch cover member, an instrument cover member, or a spectacle lens. Examples of the base material of the translucent member include sapphire glass, quartz glass, and soda glass.

According to the present invention, the predetermined antireflection layer is formed on the substrate, and the content of silicon nitride in the range from the outermost surface of the antireflection layer to a depth of 150 nm is 30 vol% or more. A high antireflection layer can be formed on the substrate. When the content of silicon nitride in the range up to the predetermined depth is less than 30 vol%, the antireflection layer has insufficient scratch resistance, and, for example, the practicality as a watch cover glass is poor. In the present invention, since the silicon nitride content in the range from the outermost surface to a depth of 150 nm is 50 vol% or less, the antireflection effect is also excellent. When the silicon nitride content in the range up to the predetermined depth exceeds 50 vol%, the antireflection effect is inferior, and, for example, the practicality as a watch cover glass is poor.
When the content of silicon nitride in the range from the outermost surface of the antireflection layer to a depth of 150 nm is 40 to 50 vol%, it is possible to further improve the scratch resistance of the antireflection layer while maintaining the antireflection effect. Therefore, it is preferable.
Moreover, the layer thickness of the outermost layer made of silicon oxide is preferably 70 to 110 nm, more preferably 75 to 105 nm. The layer thickness of the silicon nitride layer adjacent to the outermost layer is preferably 50 to 115 nm, more preferably 55 to 110 nm. When the thickness of each of these layers is out of the above range, the reflectance of the antireflection layer tends to increase.

In this invention, it is preferable that the surface hardness of this translucent member is 24000 N / mm < ² > or more. Here, the test load is 1.225 mN.
According to this invention, since the surface hardness of this translucent member is 24000 N / mm < ² > or more, sufficient scratch resistance can be exhibited, for example, it is excellent as a cover glass for watches. Further, when the surface hardness of the translucent member is 30000 N / mm ² or more, further excellent scratch resistance can be exhibited.

In the present invention, an antifouling layer made of a fluorine-containing organosilicon compound is preferably formed on the antireflection layer.
According to this invention, the antifouling layer comprising a fluorine-containing organosilicon compound is formed on the antireflection layer. Since this antifouling layer is made of a fluorine-containing organosilicon compound, it exhibits not only water and oil repellency, but also excellent surface slipperiness. Therefore, even if an impact from the outside is applied to the translucent member, the impact can be reduced by the slipperiness of the surface of the antifouling layer, so that the scratch resistance is excellent. That is, it becomes possible to effectively prevent peeling of the antireflection layer. In addition, as a fluorine-containing organosilicon compound, what is necessary is just a compound which has water repellency and oil repellency, and can express antifouling property.

In the present invention, the fluorine-containing organosilicon compound is preferably an alkoxysilane compound.
According to the present invention, since the alkoxysilane compound is used as the fluorine-containing organosilicon compound, the water and oil repellency is high and excellent antifouling properties are exhibited.
As the alkoxysilane compound, an organosilicon compound having an alkoxysilyl group such as a methoxysilyl group or a triethoxysilyl group and a perfluoro group is preferably used.

  In the present invention, the fluorine-containing organosilicon compound is preferably a perfluoroether compound represented by at least one of the following formulas (1) and (2).

（式中、Ｒ_ｆ ¹はパーフルオロアルキル基を示す。Ｘは臭素、ヨウ素または水素を示す。
Ｙは水素または低級アルキル基を示し、Ｚはフッ素またはトリフルオロメチル基を示す。Ｒ¹は加水分解可能な基を示し、Ｒ²は水素または不活性な１価の炭化水素基を示す。ａ、ｂ、ｃ、ｄ、ｅは０または１以上の整数で、且つａ＋ｂ＋ｃ＋ｄ＋ｅは少なくとも１以上であり、ａ、ｂ、ｃ、ｄ、ｅで括られた各繰り返し単位の存在順序は、式中において限定されない。ｆは０、１または２である。ｇは１、２または３である。ｈは１以上の整数である。）

(In the formula, R _f ¹ represents a perfluoroalkyl group. X represents bromine, iodine or hydrogen.
Y represents hydrogen or a lower alkyl group, and Z represents a fluorine or trifluoromethyl group. R ¹ represents a hydrolyzable group, and R ² represents hydrogen or an inert monovalent hydrocarbon group. a, b, c, d and e are 0 or an integer of 1 or more, a + b + c + d + e is at least 1 and the order of presence of each repeating unit enclosed by a, b, c, d and e is as follows: It is not limited in. f is 0, 1 or 2. g is 1, 2 or 3. h is an integer of 1 or more. )

（式中、Ｒ_ｆ ²は式：「−（Ｃ_kＦ_2k）Ｏ−」で示される単位を含み、分岐を有しない直鎖状のパーフルオロポリアルキレンエーテル構造を有する２価の基を示す。なお、式：「−（Ｃ_kＦ_2k）Ｏ−」におけるｋは１〜６の整数である。Ｒ³は炭素原子数１〜８の１価炭化水素基であり、Ｗは加水分解性基またはハロゲン原子を示す。ｐは０、１または２であり、ｎは１〜５の整数である。ｍおよびｒは、２または３である。）

(Wherein R _f ² represents a divalent group having a linear perfluoropolyalkylene ether structure containing a unit represented by the formula: “— (C _k F _2k ) O—” and having no branch). In the formula: “— (C _k F _2k ) O—”, k is an integer of 1 to 6. R ³ is a monovalent hydrocarbon group having 1 to 8 carbon atoms, and W is hydrolyzable. Represents a group or a halogen atom, p is 0, 1 or 2, n is an integer of 1 to 5. m and r are 2 or 3.)

  According to the present invention, the fluorine-containing organosilicon compound represented by at least one of the above formulas (1) and (2) is formed on the antireflection layer, thereby having excellent antifouling properties. A translucent member can be obtained. These fluorine-containing organosilicon compounds may be used alone or in combination.

In the present invention, the antifouling layer preferably has a thickness of 0.001 to 0.05 μm, more preferably 0.001 to 0.03 μm, and further preferably 0.001 to 0.02 μm. preferable.
When the thickness of the antifouling layer is 0.001 μm or more, sufficient water and oil repellency can be exhibited, and scratch resistance and chemical resistance can be improved. Moreover, there is also little possibility that the surface hardness of a translucent member will fall that the thickness of an antifouling layer is 0.05 micrometer or less. Furthermore, since the surface light scattering by the antifouling layer does not occur so much, the transparency of the substrate is not inhibited.

In the present invention, it is preferable that the translucent member is a cover member, and the antireflection layer is formed on at least an outer portion of an inner portion and an outer portion of the cover member.
According to the present invention, since the reflection of light incident from the outside of the cover member can be prevented on the incident side, the antireflection effect is better than when the antireflection layer is formed on the exit side portion inside the cover member. Is obtained.

The timepiece of the present invention includes the translucent member, and the translucent member is provided in a case that houses the timepiece.
The timepiece of the present invention can have the same operations and effects as described above by including the above-described translucent member. In addition, a translucent member is provided in a case as a cover glass (windshield), for example.

The manufacturing method of the translucent member of this invention is equipped with the sputtering process which forms the high refractive index layer and low-refractive-index layer which comprise the said reflection preventing layer by sputtering.
According to the present invention, since the antireflection layer is formed by sputtering, not only the high refractive index layer and the low refractive index layer are formed by simple vapor deposition, but also the overall hardness of the antireflection layer can be improved. In addition, the adhesion between the antireflection layer and the substrate and the interlayer adhesion in the antireflection layer are also excellent. Therefore, as a result, it can contribute to improvement of scratch resistance.

Here, when performing the above-mentioned sputtering, it is preferable from a viewpoint of the above-mentioned hardness and adhesiveness to provide the heating process which performs sputtering, heating a base material to 100 degreeC or more.
Moreover, since the base material surface can be cleaned by providing a reverse sputtering step for removing surface deposits on the base material before forming the antireflection layer by sputtering, the base material and the antireflection layer From the viewpoint of improving adhesion to the substrate.

  According to the present invention, it is possible to provide a translucent member having both an antireflection function and scratch resistance, a timepiece including the translucent member, and a method of manufacturing the translucent member.

The schematic diagram which shows the cross section of the cover glass which concerns on 1st Embodiment of this invention. The schematic diagram which shows the cross section of the cover glass which concerns on 2nd Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail.
[First Embodiment]
The translucent member (cover member) according to the first embodiment is, for example, a watch cover glass (hereinafter also simply referred to as “cover glass”), and FIG. 1 shows a cross section of the cover glass 1 of the present embodiment. The figure is shown. The cover glass 1 includes a transparent substrate 11 and an antireflection layer 12 formed thereon.

[Material of Substrate 11]
The material of the substrate 11 is an inorganic oxide, and examples thereof include sapphire glass, quartz glass, and soda glass. As a material of the watch cover glass, sapphire glass is particularly preferable from the viewpoints of hardness and transparency.

[Configuration of Antireflection Layer 12]
The antireflection layer 12 is a multilayer film formed on the substrate 11 and obtained by alternately laminating inorganic thin films having different refractive indexes. In the cover glass 1 shown in FIG. 1, the antireflection layer 12 includes four layers of 12A (high refractive index layer), 12B (low refractive index layer), 12C (high refractive index layer), and 12D (low refractive index layer). It is configured.
Here, the high refractive index layers 12A and 12C are formed of silicon nitride (SiNx), and the low refractive index layers 12B and 12D are formed of silicon oxide (SiO ₂ ). The silicon nitride content in the range from the outermost surface of the antireflection layer 12 to a depth of 150 nm is 30 to 50 vol%.

The antireflection layer 12 need not be four layers, and may be five layers or more. From the viewpoint of enhancing the antireflection effect, a larger number of layers is preferable. However, if the number of laminated layers is too large, a problem may occur from the viewpoint of productivity, so the range is preferably up to 9 layers.
The layer thickness of the outermost layer (low refractive index layer 12D) made of silicon oxide is preferably 70 to 110 nm, and more preferably 75 to 105 nm. The layer thickness of the silicon nitride layer (high refractive index layer 12C) adjacent to the outermost layer is preferably 50 to 115 nm, more preferably 55 to 110 nm. When the above-mentioned range of the layer thickness is deviated, the reflectance of the antireflection layer 12 tends to increase.
Here, the surface hardness of the cover glass 1 shown in FIG. 1 is 24000 N / mm ² or more as measured according to ISO14577 using a nanoindenter (test load 1.225 mN).

[Formation process of antireflection layer 12]
When forming the above-described antireflection layer 12 on the surface of the substrate 11, a sputtering method is suitably used. Note that a vacuum deposition method can also be applied. In the vacuum deposition method, a technique such as ion beam assist can be used in combination as appropriate. However, in order to obtain the antireflection layer 12 having excellent hardness, the sputtering method is most preferable. As the sputtering method and the vacuum evaporation method, a normal method used for forming an inorganic thin film can be applied.
Moreover, when performing above-described sputtering, it is preferable from a viewpoint of the above-mentioned hardness and adhesiveness to provide the heating process which heats the base material 11 to 100 degreeC or more.
In addition, before the antireflection layer 12 is formed by sputtering, the surface of the base material 11 can be cleaned by providing a reverse sputtering process for removing deposits on the surface of the base material 11. 11 is preferable from the viewpoint of improving the adhesion between the antireflection layer 12 and the antireflection layer 12.

According to the above embodiment, the following effects are obtained.
The cover glass 1 includes a transparent base material 11 and an antireflection layer 12. The antireflection layer 12 is formed by alternately laminating the high refractive index layers 12A and 12C and the low refractive index layers 12B and 12D. In the range from the outermost surface of the antireflection layer 12 to a depth of 150 nm. The silicon nitride content is 30 to 50 vol%. Therefore, the surface of the antireflection layer 12 is a very hard layer. When the content of silicon nitride in the range up to the predetermined depth is less than 30 vol%, the antireflection layer 12 has insufficient scratch resistance, and, for example, the practicality as a watch cover glass is poor. Further, since the silicon nitride content in the range from the outermost surface of the antireflection layer 12 to a depth of 150 nm is 50 vol% or less, the antireflection effect is also excellent. When the silicon nitride content in the range up to the predetermined depth exceeds 50 vol%, the antireflection effect is inferior and the practicality as a watch cover glass is poor. When the content of silicon nitride in the range from the outermost surface of the antireflection layer 12 to a depth of 150 nm is 40 vol% or more, it is possible to further improve the scratch resistance of the antireflection layer while maintaining the antireflection effect. Become.

Since the surface hardness of the cover glass 1 is 24000 N / mm ² or more, sufficient scratch resistance can be exhibited, and sufficient scratch resistance can be obtained when applied to a wristwatch or a portable information device. Further, when the surface hardness is 30000 N / mm ² or more, further excellent scratch resistance can be exhibited.

[Second Embodiment]
An antifouling layer can be formed on the antireflection layer 12 described above. FIG. 2 shows a cover glass 2 in which an antifouling layer 13 is further formed on the antireflection layer 12 described above. Hereinafter, the antifouling layer 13 will be described.
[Configuration of Antifouling Layer 13]
The antifouling layer 13 is composed of a compound known as a so-called water / oil repellent. Such a compound is preferably a fluorine-containing organosilicon compound such as alkoxysilane.
For _{example, CF 3 (CF 2) 2} C 2 H 4 Si (OCH 3) 3, CF 3 (CF 2) 4 C 2 H 4 Si (OCH 3) 3, CF 3 (CF 2) 6 C 2 H 4 Si (OCH ₃ ) ₃ , CF ₃ (CF ₂ ) ₈ C ₂ H ₄ Si (OCH ₃ ) ₃ , CF ₃ (CF ₂ ) ₁₀ C ₂ H ₄ Si (OCH ₃ ) ₃ , CF ₃ (CF ₂ ) ₁₂ C ₂ H ₄ Si (OCH ₃ ) ₃ , CF ₃ (CF ₂ ) ₁₄ C ₂ H ₄ Si (OCH ₃ ) ₃ , CF ₃ (CF ₂ ) ₁₆ C ₂ H ₄ Si (OCH ₃ ) ₃ , CF ₃ (CF _{2) 18 C 2 H 4 Si} (OCH 3) 3, CF 3 (CF 2) 6 C 2 H 4 Si (OC 2 H 5) 3, CF 3 (CF 2) 8 C 2 H 4 Si (OC 2 H _{5) 3, CF 3 (CF} 2) 6 C 2 H 4 _{iCl 3, CF 3 (CF 2} ) 8 C 2 H 4 SiCl 3, CF 3 (CF 2) 6 C 3 H 6 Si (OCH 3) 3, CF 3 (CF 2) 8 C 3 H 6 Si (OCH 3 ) ₃ , CF ₃ (CF ₂ ) ₆ C ₃ H ₆ Si (OC ₂ H ₅ ) ₃ , CF ₃ (CF ₂ ) ₈ C ₃ H ₆ Si (OC ₂ H ₅ ) ₃ , CF ₃ (CF ₂ ) _{6 C 3 H 6 SiCl 3, CF} 3 (CF 2) 8 C 3 H 6 SiCl 3, CF 3 (CF 2) 6 C 4 H 8 Si (OCH 3) 3, CF 3 (CF 2) 8 C 4 H 8 Si (OCH ₃ ) ₃ , CF ₃ (CF ₂ ) ₆ C ₄ H ₈ Si (OC ₂ H ₅ ) ₃ , CF ₃ (CF ₂ ) ₈ C ₄ H ₈ Si (OC ₂ H ₅ ) ₃ , CF ₃ ( _{CF 2) 6 C 2 H 4} Si (CH 3) (OCH 3 _{2, CF 3 (CF 2)} 8 C 2 H 4 Si (CH 3) (OCH 3) 2, CF 3 (CF 2) 6 C 2 H 4 Si (CH 3) Cl 2, CF 3 (CF 2) 8 _{C 2 H 4 Si (CH 3} ) Cl 2, CF 3 (CF 2) 6 C 2 H 4 Si (C 2 H 5) (OC 2 H 5) 2, and _{CF 3 (CF 2) 8 C} 2 H 4 _{Si (C 2 H 5) (} OC 2 H 5) 2 and the like.
As the fluorine-containing organosilicon compound, a compound containing an amino group is also suitable.
For example, C ₉ F ₁₉ CONH (CH ₂ ) ₃ Si (OC ₂ H ₅ ) ₃ , C ₉ F ₁₉ CONH (CH ₂ ) ₃ SiCl ₃ , C ₉ F ₁₉ CONH (CH ₂ ) ₃ Si (CH ₃ ) Cl _{2, C 9 F 19 CONH (} CH 2) NH (CH 2) Si (OC 2 H 5) 3, C 9 F 19 CONH (CH 2) 5 CONH (CH 2) Si (OC 2 H 5) 3, C _{8 F 17 SO 2 NH (CH} 2) 5 CONH (CH 2) Si (OC 2 H 5) 3, C 3 F 7 O (CF (CF 3) CF 2 O) 2 -CF (CF 3) -CONH ( _{CH 2) Si (OC 2 H} 5) 3, and _{C 3 F 7 O (CF (} CF 3) CF 2 O) m'-CF (CF 3) -CONH (CH 2) Si (OCH 3) 3 [ where M ′ is an integer greater than or equal to 1] And the like.
Moreover, as a fluorine-containing organosilicon compound, the following compounds are also suitable.
For example, Rf ′ (CH ₂ ) ₂ SiCl ₃ , Rf ′ (CH ₂ ) ₂ Si (CH ₃ ) Cl ₂ , (Rf′CH ₂ CH ₂ ) ₂ SiCl ₂ , Rf ′ (CH ₂ ) ₂ Si (OCH ₃ ) ) ₃ , Rf′CONH (CH ₂ ) ₃ Si (OC ₂ H ₅ ) ₃ , Rf′CONH (CH ₂ ) ₂ NH (CH ₂ ) ₃ Si (OC ₂ H ₅ ) ₃ , Rf′SO ₂ N (CH ₃ ) (CH ₂ ) ₂ CONH (CH ₂ ) ₃ Si (OC ₂ H ₅ ) ₃ , Rf ′ (CH ₂ ) ₂ OCO (CH ₂ ) ₂ S (CH ₂ ) ₃ Si (OCH ₃ ) ₃ , Rf ′ _{(CH 2) 2 OCONH (CH} 2) 2 Si (OC 2 H 5) 3, Rf'COO-Cy (OH) - (CH 2) 2 Si (OCH 3) 3, Rf '(CH 2) 2 NH ( _{CH 2) 2 Si (OCH 3} ) 3, and Rf ' _{CH 2) 2 NH (CH 2} ) 2 NH (CH 2) 2 Si (OCH 2 CH 2 OCH 3) 3 and the like. In each of the above formulas, Cy is a cyclohexane residue, and Rf ′ is a polyfluoroalkyl group having 4 to 16 carbon atoms.

  As the fluorine-containing organosilicon compound used in the present invention, a compound represented by at least one of the following formulas (1) and (2) is particularly preferable.

In the formula, R _f ¹ represents a perfluoroalkyl group. X represents bromine, iodine or hydrogen.
Y represents hydrogen or a lower alkyl group, and Z represents a fluorine or trifluoromethyl group. R ¹ represents a hydrolyzable group, and R ² represents hydrogen or an inert monovalent hydrocarbon group. a, b, c, d and e are 0 or an integer of 1 or more, a + b + c + d + e is at least 1 and the order of presence of each repeating unit enclosed by a, b, c, d and e is as follows: It is not limited in. f is 0, 1 or 2. g is 1, 2 or 3. h is an integer of 1 or more.

In the formula, R _f ² represents a divalent group having a linear perfluoropolyalkylene ether structure containing a unit represented by the formula: “— (C _k F _2k ) O—” and having no branch. In the formula: “— (C _k F _2k ) O—”, k is an integer of 1-6. R ³ is a monovalent hydrocarbon group having 1 to 8 carbon atoms, and W represents a hydrolyzable group or a halogen atom. p is 0, 1 or 2, and n is an integer of 1-5. m and r are 2 or 3.

By forming the fluorine-containing organosilicon compound as the antifouling layer 13 on the antireflection layer 12, a cover glass having excellent water and oil repellency effects and excellent scratch resistance is obtained. be able to. These fluorine-containing organosilicon compounds may be used alone or in combination. In particular, it is preferable to use a mixture of the compounds of the above formulas (1) and (2) because the durability of the antifouling layer is improved.
Specific examples of the fluorine-containing organosilicon compound include GE Toshiba Silicones Co., Ltd. TSL8233, TSL8257, Daikin Industries, Ltd. OPTOOL DSX, Shin-Etsu Chemical Co., Ltd. KY-130, KP-801, and the like.

[Formation process of antifouling layer 13]
As a method for forming the antifouling layer 13, either a dry method or a wet method can be used. Each will be described below.

(Dry method)
As the dry method, a vacuum vapor deposition method in which the fluorine-containing organosilicon compound is evaporated in a vacuum chamber and adhered to the surface of the substrate 11 (antireflection layer 12) can be employed. For example, the vapor deposition apparatus described in Unexamined-Japanese-Patent No. 6-340966 and Unexamined-Japanese-Patent No. 2005-301208 can be utilized suitably. Specifically, the antifouling layer 13 can be formed as follows.

  A treatment agent obtained by dissolving and diluting a fluorine-containing organosilicon compound in an appropriate fluorine-based solvent is attached to a fibrous or porous medium, and this is applied in a vacuum chamber under a pressure of 1 to 0.0001 Pa. By heating, the antifouling layer 13 is formed on the antireflection layer 12 of the cover glass 2 placed in the vacuum chamber. As the fluorine-based solvent to be used, the same solvents as those used in the wet method described later can be used. In addition, the amount of solvent used is small and there is almost no environmental impact.

As such a medium, a conductive fiber or a porous sintered metal is preferable from the viewpoint of thermal conductivity and heating efficiency, and copper or stainless steel is preferable as a material. Here, as a porous medium such as a sintered metal, the pore diameter is preferably 40 to 200 μm, more preferably 80 to 120 μm, from the viewpoint of obtaining an appropriate deposition rate.
The temperature at which the fluorine-containing organosilicon compound adhered to the medium is heated when the antifouling layer 13 is formed varies depending on the pressure in the vacuum chamber, but is set within a range not exceeding the decomposition temperature of the organosilicon compound. It is preferable.

  The pressure when forming the antifouling layer 13 is preferably 0.5 to 0.005 Pa, more preferably 0.1 to 0.001 Pa. When the pressure at the time of forming the antifouling layer 13 is higher than 1 Pa, the average free process of the evaporated molecules is short, and the formation rate of the antifouling layer 13 is slowed. On the other hand, if the pressure is lower than 0.0001 Pa, the formation speed of the antifouling layer 13 increases, but it is not preferable because it takes too much time to obtain such a vacuum state.

The formation rate (deposition rate) of the antifouling layer 13 is preferably 0.05 to 5.0 Å / s, more preferably 0.1 to 2.0 Å / s. If it is less than 0.05 kg / s, the production cost is excessive because of low productivity. On the other hand, if it exceeds 2.0 kg / s, the layer thickness distribution of the antifouling layer 13 becomes non-uniform, and the surface slipperiness deteriorates. Here, the formation speed of the antifouling layer 13 can be controlled by adjusting the pressure in the vacuum chamber and the heating temperature.
In the vacuum deposition method, the fluorine-containing organosilicon compound can be used at a high concentration or without a diluting solvent.

(Wet method)
<Preparation of treatment agent>
In order to form the antifouling layer 13 on the substrate 11 (antireflection layer 12) by a wet method, any of the fluorine-containing organosilicon compounds described above is dissolved in an organic solvent so as to have a predetermined concentration. It is possible to adopt a method of adjusting to the surface of the substrate 11 and applying it to the surface of the substrate 11. The organic solvent is preferably an organic compound having a perfluoro group excellent in solubility of the fluorine-containing organosilicon compound and having 4 or more carbon atoms, such as perfluorohexane, perfluorocyclobutane, perfluorooctane, perfluorodecane. Perfluoromethylcyclohexane, perfluoro-1,3-dimethylcyclohexane, perfluoro-4-methoxybutane, perfluoro-4-ethoxybutane, and metaxylene hexafluoride. Moreover, perfluoroether oil and chlorotrifluoroethylene oligomer oil can be used. In addition, CFC 225 (a mixture of CF ₃ CF ₂ CHCl ₂ and CClF ₂ CF ₂ CHClF) can be exemplified. One of these organic solvents can be used alone or in admixture of two or more.

  The concentration when diluted with an organic solvent is preferably in the range of 0.03 to 1% by mass. If it is lower than 0.03% by mass, it is difficult to form the antifouling layer 13 having a sufficient thickness, and sufficient water and oil repellency effects and sufficient slipperiness may not be obtained. On the other hand, if it is thicker than 1% by mass, the antifouling layer 13 may be too thick, and the burden of rinsing work for eliminating coating unevenness after application may increase.

<Application process>
As a coating method, dipping (dipping) method, spin coating method, spray method, flow method, doctor blade method, roll coat coating, gravure coat coating, curtain flow coating, brush coating and the like are used. The layer thickness of the antifouling layer 13 is not particularly limited, but is preferably 0.001 to 0.05 μm, more preferably 0.001 to 0.03 μm, and further preferably 0.001 to 0.02 μm. preferable.
When the thickness of the antifouling layer 13 is less than 0.001 μm, sufficient water and oil repellency cannot be exhibited and the slipperiness is poor, so that the scratch resistance and chemical resistance may be lowered. Further, if the thickness of the antifouling layer exceeds 0.05 μm, the surface hardness of the cover glass 2 may be reduced, and further, surface light scattering by the antifouling layer 13 is increased, thereby impairing the transparency of the base material 11. There is a fear.

  In the case of the dipping method, the base material 11 is immersed in a treatment liquid adjusted to a predetermined concentration using the above-described organic solvent, and after a predetermined time has elapsed, the base material 11 is pulled up at a constant speed. At this time, the immersion time is preferably about 0.5 to 3 minutes. When the time is less than 0.5 minutes, the fluorine-containing organosilicon compound is not sufficiently adsorbed on the surface of the base material 11, so that predetermined water / oil repellency and slipperiness cannot be obtained. If it exceeds 3 minutes, the cycle time increases, which is not preferable. The pulling speed is preferably 100 mm / min to 300 mm / min. This is determined in consideration of the concentration of the treatment solution. If the concentration is less than 100 mm / min, the antifouling layer 13 becomes too thin to obtain a predetermined performance. If the concentration exceeds 300 mm / min, the antifouling layer 13 becomes too thick, and there is a possibility that the burden of rinsing work for eliminating coating unevenness after application increases.

<Aging process>
After the coating step, it is allowed to stand for 0.5 hours or more in an atmosphere having a temperature of 10 to 60 ° C. and a relative humidity of 10 to 90%. The temperature is preferably 20-50 ° C. and the relative humidity is preferably 20-80%. The standing time (ripening time) is preferably 1 to 10 hours. If the atmospheric temperature is too low, the organosilicon compound has low reactivity, so that the antifouling layer 13 is not sufficiently formed. Conversely, if the ambient temperature is too high, the antifouling layer 13 may crack and the appearance of the cover glass 2 may be poor. On the other hand, if the atmospheric humidity is too low, the anti-staining layer 13 is not sufficiently formed because the reactivity of the organosilicon compound is low as in the case of temperature. If the atmospheric humidity is too high, the reaction will be too fast and the antifouling layer 13 will crack and the appearance of the cover glass 2 may be poor. On the other hand, if the aging time is too short, the reaction of the organosilicon compound becomes insufficient and the formation of the antifouling layer 13 becomes insufficient. The aging time is required to be 0.5 hours or longer. For example, it is preferably about 24 hours when the temperature is 25 ° C. and the relative humidity is 40%, and about 2 hours when the temperature is 60 ° C. and the relative humidity is 80%.
In either of the dry method and the wet method described above, it is preferable to perform plasma treatment (argon, oxygen, etc.) on the surface of the antireflection layer 12 in advance. For example, if the plasma treatment is performed on the antireflection layer 12 (low refractive index layer 12D, SiO ₂ layer), the adhesion (adhesion) between the antireflection layer 12 and the antifouling layer 13 is greatly improved. To do.

The surface hardness of the cover glass 2 on which the antifouling layer 13 is finally formed is 24000 N / mm ² or more as measured by ISO14577 using a nanoindenter (test load 1.225 mN).

According to the above embodiment, the following effects can be obtained.
On the antireflection layer 12, an antifouling layer 13 made of a fluorine-containing organosilicon compound is formed. Therefore, this antifouling layer not only exhibits water and oil repellency, but also has excellent surface slipperiness. Therefore, even if an impact from the outside is applied to the cover glass 2, the impact can be reduced by the slipperiness of the surface of the antifouling layer 13, so that the scratch resistance is very excellent. Therefore, the visibility of the cover glass 2 can be maintained for a long time.
By using an alkoxysilane compound or a perfluoroether compound such as the above-described formulas (1) and (2) as the fluorine-containing organosilicon compound used for the antifouling layer 13, high slipperiness is imparted to the cover glass 2. As a result, excellent scratch resistance can be exhibited.

By setting the thickness of the antifouling layer 13 in the range of 0.001 to 0.05 μm, the cover glass 1 can exhibit sufficient water and oil repellency, and has excellent scratch resistance and chemical resistance. Can provide.
Since the surface hardness of the cover glass 1 is 24000 N / mm ² or more, sufficient scratch resistance can be obtained when applied to a wristwatch or a portable information device.

When the antifouling layer 13 is formed by the predetermined wet method described above, not only the cover glass 2 having excellent scratch resistance can be produced, but also large equipment such as a vacuum apparatus is not required, and the production cost can be reduced. It becomes possible.
Further, when the antifouling layer 13 is formed by the above-described predetermined dry method, not only the cover glass 2 having excellent scratch resistance can be produced, but also the environmental load is low because a solvent is not substantially used. Moreover, since it is easy to change the conditions in the formation process of the antifouling layer 13, the layer thickness control of the antifouling layer is also simple. Furthermore, the heating efficiency of the fluorine-containing organosilicon compound is high by using a fibrous or porous medium.

The present invention is not limited to the above-described embodiments, and various improvements and modifications can be made within a range in which the object of the present invention can be achieved.
In the said embodiment, although the example in which this invention was applied to the cover glasses 1 and 2 as a windshield was shown, the translucent member of this invention is not limited to the cover glass as a windshield. In a mechanical timepiece or the like, a translucent member as a cover member is provided at a position where a back cover is provided, and a see-through back specification is provided in which a mechanism inside the watch body can be visually recognized through the translucent member. Sometimes. In such a case, the present invention can be applied to the translucent member.
In addition, as a base material of a translucent member, high-hardness sapphire glass is suitable, but use of quartz glass, soda glass, or the like may also be considered.

The translucent member of the present invention is not limited to a cover member used in a watch, but covers information display units in various devices such as mobile phones, portable information devices, measuring devices, digital cameras, printers, diving computers, and pulse meters. It can be suitably used as a member.
The translucent member of the present invention is not limited to the cover member. The antireflection layer and the antifouling layer according to the present invention are formed at any location where hardness, antireflection function, and scratch resistance are required in the base material of the translucent member.

  Hereinafter, the present invention will be described in more detail by way of examples and comparative examples. Specifically, after using a general sapphire glass as the base material 11 of the watch cover glasses 1 and 2 shown in FIGS. 1 and 2, and forming a predetermined antireflection layer and further an antifouling layer on the surface thereof Various evaluations were made.

[Examples 1 to 16, Comparative Examples 1 to 12]
(Pretreatment of substrate 11)
After sapphire glass was immersed in hot concentrated sulfuric acid at 120 ° C. for 10 minutes, it was thoroughly washed with pure water and dried in the atmosphere for 30 minutes in an oven set at 120 ° C. Next, after this sapphire glass was placed inside the sputtering apparatus, the inside of the apparatus was brought to a pressure of 10 ⁻⁶ Torr while heating to 120 ° C. Subsequently, Ar gas was introduced into the apparatus, and the surface of the sapphire glass was cleaned by reverse sputtering at 0.8 mTorr.

(Formation of the antireflection layer 12)
Sputtering was performed under the following conditions using silicon as a target, and antireflection layers 12 (4 to 9 layers) composed of a high refractive index layer and a low refractive index layer were formed on the surface of the sapphire glass substrate 11. Specific layer structures are shown in Tables 1 and 2. The volume fraction of silicon nitride (SiNx) from the outermost surface of the antireflection layer 12 to a depth of 150 nm is shown as the SiNx occupancy rate.
High refractive index layer: silicon nitride (SiNx)
N ₂ gas: 10.0 sccm
Ar gas: 10.0sccm
Sputtering power: 2.0KW
Low refractive index layer: silicon oxide (SiO ₂ )
0 ₂ Gas: 10.0sccm
Ar gas: 10.0sccm
Sputtering power: 1.5KW

[Evaluation items and methods]
The following evaluation was performed on the base material 11 obtained above, and the results are shown in Tables 1 and 2. A single sapphire glass is also shown as a reference example.
(1) Reflectance (%)
The reflectance of standard light incident on the substrate surface at an incident angle of 90 ° is obtained, and this reflectance is multiplied by the luminous sensitivity at an incident angle of 90 ° at each wavelength in the visible light region. It calculated based on the integrated value.

(2) Light transmittance difference before and after sandfall test (ΔT%)
First, the following sandfall test is performed. The cover glass is arranged at an inclination angle of 45 ° with respect to the horizontal plane. At this time, the cover glass is arranged so that the side on which the antireflection layer 12 is formed is the upper surface side. Then, the sand is dropped toward the antifouling layer from a height of 1 m from the horizontal plane. Thereafter, the cover glass was washed, and the difficulty of scratching was evaluated based on the difference ΔT% between the light transmittance of the cover glass before the test and the light transmittance of the cover glass after the test.
Here, the sand used is a carborundum produced by pulverizing and classifying black silicon carbide ingot and green silicon carbide ingot. In this test, 800 cm ³ of Carborundum # 24 having a center particle size of 600 to 850 μm was used.

(3) Surface hardness (N / mm ² )
Using a nanoindenter, the surface hardness of the antireflection layer side of the base material 11 at a test load of 1.225 mN was measured (based on ISO14577).

〔Evaluation results〕
From the results of Table 1, regardless of the number of antireflection layers 12, the surface hardness is maintained at 24000 N / mm ² or more by setting the SiNx occupancy from the outermost surface to a depth of 150 nm at 30 to 50 vol%. It is understood that the transmittance difference (Δ%) before and after the sandfall test can be reduced to 2% or less. When the transmittance difference is 2% or less, it can be said that practical scratch resistance is good as a watch cover glass. Moreover, the transmittance | permeability difference before and after the sandfall test can be further reduced to 1.5% or less by setting the SiNx occupation ratio to 40 vol% or more. If the transmittance difference is 1.5% or less, it can be said that the practical scratch resistance is very good.
On the other hand, from the results in Table 2, as shown in Comparative Examples 1, 3, 5, 7, 9, and 11, when the SiNx occupancy exceeds 50 vol%, the reflectance exceeds 0.4% and is practically used. It turns out that it becomes a difficult level. Further, as shown in Comparative Examples 2, 4, 6, 8, 10, and 12, when the SiNx occupancy is less than 30 vol%, the surface hardness is very small and the transmittance difference is also large. That is, the scratch resistance is inferior.

[Examples 17 to 22]
For the above-described Examples 1, 3, 5, 8, 11, and 14, the antifouling layer 13 was further formed on the surface of the antireflection layer 12 and evaluated in the same manner.
(Formation of antifouling layer 13)
Fluorine-containing organosilicon compound (KY-130 (3), manufactured by Shin-Etsu Chemical Co., Ltd.) diluted with a fluorine-based solvent (FR thinner, manufactured by Shin-Etsu Chemical Co., Ltd.) to obtain a solid content of 3% by weight is obtained from steel wool ( Packed with 1.0 g in a container (Japanese cylindrical wool # 0, wire diameter 0.025 mm) pre-filled with 0.5 g (cylindrical copper container with open top, inner diameter 16 mm × inner height 6 mm) And dried at 120 ° C. for 1 hour. Next, this copper container is placed in a vacuum evaporator together with the sapphire glass on which the antireflection layer is formed, and the inside of the apparatus is set to a pressure of 0.01 Pa. The fluorine-containing organosilicon compound was evaporated from the copper container so that the film formation rate (deposition rate) of s was obtained. As a heating source, a resistance heating boat made of molybdenum was used.

(Evaluation of characteristics of cover glass 2)
About the cover glass 2 manufactured on said manufacturing conditions, each above-mentioned characteristic was evaluated. The results are shown in Table 3.

〔Evaluation results〕
As shown in Table 3, each of the cover glasses 2 of Examples 17 to 22 has an antifouling layer, but the cover glass 1 (Examples 1, 3, 5, 8, 11) serving as a base thereof. 14), it is understood that the antireflection effect and scratch resistance are excellent. That is, it can be seen that even if the antifouling layer is formed, the effect of the SiNx occupation ratio is strongly reflected.

1, 2 ... Cover glass (translucent member, cover member), 11 ... Base material, 12 ... Antireflection layer, 12A, 12C ... High refractive index layer, 12B, 12D ... Low refractive index layer, 13 ... Antifouling layer

Claims (8)

A cover member comprising a base material having translucency,
At least a part of the surface of the substrate includes
A laminate as an antireflection layer including a layer containing silicon nitride and a layer containing silicon oxide,
The stack has a silicon nitride content of 40 to 50 vol% in a range from the outermost surface to a depth of 150 nm.
The surface of the laminate has an antifouling layer containing a fluorine-containing organosilicon compound,
The antifouling layer has a thickness of 0.001 to 0.05 μm,
The cover member is provided in an information display unit of a portable information device,
The cover member has a surface hardness of 24000 N / mm ² or more. A cover member comprising a base material having translucency,
At least a part of the surface of the substrate includes
A laminate as an antireflection layer including a layer containing silicon nitride and a layer containing silicon oxide,
The laminate has a silicon nitride content of 30 to 50 vol% in a range from the outermost surface to a depth of 150 nm,
The surface of the laminate has an antifouling layer containing a fluorine-containing organosilicon compound,
The antifouling layer has a thickness of 0.001 to 0.05 μm,
The stack is formed by stacking the layer containing silicon nitride and the layer containing silicon oxide, and the number of stacks is four.
The cover member is provided in an information display unit of a portable information device,
The cover member has a surface hardness of 24000 N / mm ² or more. The cover member according to claim 1 or 2,
The said base material is sapphire glass. The cover member characterized by the above-mentioned. In the cover member in any one of Claims 1-3,
The cover member has a surface hardness of 30000 N / mm ² or more. In the cover member in any one of Claims 1-4,
The cover member, wherein the fluorine-containing organosilicon compound is an alkoxysilane compound. In the cover member in any one of Claims 1-5,
The fluorine-containing organosilicon compound is a perfluoroether compound represented by at least one of the following formulas (1) and (2).

(In the formula, R _f ¹ represents a perfluoroalkyl group. X represents bromine, iodine or hydrogen.
Y represents hydrogen or a lower alkyl group, and Z represents a fluorine or trifluoromethyl group. R ¹ represents a hydrolyzable group, and R ² represents hydrogen or an inert monovalent hydrocarbon group. a, b, c, d and e are 0 or an integer of 1 or more, a + b + c + d + e is at least 1 and the order of presence of each repeating unit enclosed by a, b, c, d and e is as follows: It is not limited in. f is 0, 1 or 2. g is 1, 2 or 3. h is an integer of 1 or more. )

(In the formula, R _f ² represents a divalent group having a linear perfluoropolyalkylene ether structure containing a unit represented by the formula: “— (C _k F _2k ) O—” and having no branch). In the formula: “— (C _k F _2k ) O—”, k is an integer of 1 to 6. R ³ is a monovalent hydrocarbon group having 1 to 8 carbon atoms, and W is hydrolyzable. Represents a group or a halogen atom, p is 0, 1 or 2, n is an integer of 1 to 5. m and r are 2 or 3.) In the cover member in any one of Claims 1-6 ,
The said lamination | stacking is formed in the outer part at least among the inner part and the outer part of the said cover member, The cover member characterized by the above-mentioned. A portable information device comprising the cover member according to any one of claims 1 to 7 .

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