JP2018180006A - Cover member and mechanical timepiece - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cover member which comprises an antireflection function and has a sufficiently high hardness to secure scratch resistance, and a mobile phone comprising the cover member.SOLUTION: A cover member 2 of the present invention comprises a base material 11 having translucency. A laminate as an antireflection layer 12 including layers 12A and 12C containing silicon nitride and layers 12B and 12D containing silicon oxide is provided on at least a part of a surface of the base material 11. In the laminate, the content of silicon nitride in a range from the outermost surface thereof to a depth of 150 nm is 30-50 vol.%. An antifouling layer 13 containing a fluorine-containing organosilicon compound is provided on a surface of the laminate. The cover member 2 is provided on an information display part of equipment.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a cover member and a mechanical watch.

Conventionally, it is known to form an anti-reflection layer on a light-transmissive member called a cover glass (windshield) in order to enhance visibility such as time display. The antireflective layer is generally formed by laminating several layers to several tens of inorganic layers having different refractive indices, and when high hardness and scratch resistance are required on the surface of the cover glass, light is used. In many cases, SiO ₂ having a high transmittance, a low refractive index, and a relatively high hardness is formed as the outermost layer of the antireflective layer. For example, the surface of the cover glass for watches, SiO ₂ and the outermost layer and the lowermost layer, a technique for forming an antireflection layer and the SiO ₂ film and the Si ₃ N ₄ film are laminated alternately is disclosed (Patent Reference 1). In addition, there is also disclosed a watch windshield, which has silicon oxide (SiO ₂ ) as the outermost layer and a silicon nitride film is formed on the surface of a watch cover glass (see Patent Document 2).

Unexamined-Japanese-Patent No. 2004-271480 JP, 2006-275526, A

By the way, in a conventional wristwatch provided with an antireflective layer in which SiO ₂ films and Si ₃ N ₄ films are alternately stacked, the surface of the cover glass is often deeply scratched by daily use. However, the reason is not always clear, and it is unclear how the lamination of films with different hardness such as SiO ₂ film and Si ₃ N ₄ film affects the hardness and scratch resistance of the cover glass surface. The Therefore, the anti-reflection optical simulation in the cover glass has been performed without considering the ratio of the thickness of the SiO ₂ film to the thickness of the Si ₃ N ₄ film.

  Therefore, an object of the present invention is to provide a cover member having an anti-reflection function and having a sufficiently high hardness and ensured scratch resistance, and a mobile phone provided with the cover member.

As a result of research on the scratch resistance of the antireflective layer, we have found that the average hardness in the range of 150 nm from the outermost surface greatly affects the scratch resistance. Specifically, evaluations of hardness, scratch resistance and optical properties were repeated while changing the thicknesses of the relatively soft SiO ₂ film and the hard Si ₃ N ₄ film variously. As a result, it was found that the greater the hardness from the outermost surface of the antireflective layer to 150 nm, the higher the scratch resistance, but the increase in hardness at positions deeper than 150 nm has little effect on the scratch resistance. In addition, it has been found that when the ratio of the Si ₃ N ₄ film is 30 to 50 vol% in the range of 150 nm from the outermost surface of the antireflective layer, there are conditions under which high scratch resistance and low reflectance can be compatible.

The present invention is a light transmitting member comprising a light transmitting base material, wherein at least a part of the surface of the base material has a high refractive index layer made of silicon nitride and a low refractive index made of silicon oxide. An antireflective layer is formed by alternately laminating layers and the antireflective layer is characterized in that the content of silicon nitride in the range from the outermost surface to the depth of 150 nm is 30 to 50 vol%. .
Here, as the light-transmissive member, for example, a hard and transparent member such as a watch cover member, an instrument cover member, or a spectacle lens may be mentioned. As a base material of a translucent member, sapphire glass, quartz glass, soda glass etc. are mentioned.

According to the present invention, the predetermined antireflective layer is formed on the base material, and the content of silicon nitride in the range from the outermost surface of the antireflective layer to the depth of 150 nm is 30 vol% or more. A high antireflective 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 scratch resistance of the antireflective layer becomes insufficient, and for example, the practicability as a cover glass for a watch becomes poor. Further, in the present invention, since the content of silicon nitride in the range from the outermost surface to the depth of 150 nm is 50 vol% or less, the antireflection effect is also excellent. When the content of silicon nitride in the range up to the predetermined depth exceeds 50 vol%, the antireflective effect is inferior, and for example, the practicability as a cover glass for a watch becomes poor.
When the content of silicon nitride in the range from the outermost surface of the antireflective layer to the depth of 150 nm is 40 to 50 vol%, the scratch resistance of the antireflective layer can be further improved while maintaining the antireflective effect It is preferable because
Moreover, it is preferable that the layer thickness of the outermost layer which consists of silicon oxides is 70-110 nm, More preferably, it is 75-105 nm. The 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 layer thickness of each of these layers deviates from the above range, the reflectance of the antireflective layer tends to be high.

In the present invention, the surface hardness of the light-transmissive member is preferably 24000 N / mm ² or more. Here, the test load is 1.225 mN.
According to the present invention, since the surface hardness of the light-transmissive member is 24000 N / mm ² or more, sufficient scratch resistance can be exhibited, and for example, it is excellent as a cover glass for a watch. In addition, when the surface hardness of the light-transmissive member is 30,000 N / mm ² or more, the scratch resistance can be further enhanced.

In the present invention, it is preferable that an antifouling layer composed of a fluorine-containing organic silicon compound is formed on the antireflective layer.
According to this invention, the antifouling layer comprising the fluorine-containing organic silicon compound is formed on the antireflective layer. Since the antifouling layer is made of a fluorine-containing organic silicon compound, it not only exerts a water and oil repellent effect, but is also very excellent in the surface slipperiness. Therefore, even if an impact from the outside is applied to the light-transmissive member, the impact can be softened by the slipperiness of the surface of the antifouling layer, so the scratch resistance is excellent. That is, it is possible to effectively prevent the peeling of the antireflective layer. In addition, as a fluorine-containing organic silicon 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 this invention, since the alkoxysilane compound is used as the fluorine-containing organic silicon compound, the water repellency and oil repellency are high, and the excellent antifouling property is 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 organic silicon 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。）

(Wherein, R _f ¹ represents a perfluoroalkyl group, and 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, e are integers of 0 or 1, and a + b + c + d + e is at least 1 or more, and the order of existence of each repeating unit enclosed by a, b, c, d, e is There is no limitation on 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 having no branch, containing a unit represented by the formula: “— (C _k F _{2 k} ) O—” Note that _k in the formula “— (C _k F _{2 k} ) O—” is an integer of 1 to 6. R ³ is a monovalent hydrocarbon group having 1 to 8 carbon atoms, and W is hydrolyzable. Group represents 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, by forming the fluorine-containing organosilicon compound represented by at least one of the above-mentioned formulas (1) and (2) on the above-mentioned antireflection layer, it has 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 thickness of the antifouling layer is preferably 0.001 to 0.05 μm, more preferably 0.001 to 0.03 μm, and still more 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 the abrasion resistance and further the chemical resistance can be improved. In addition, when the thickness of the antifouling layer is 0.05 μm or less, there is little possibility that the surface hardness of the light transmitting member is reduced. Furthermore, since the surface light scattering by the antifouling layer does not occur so much, the transparency of the substrate is not impaired.

In the present invention, preferably, the light transmitting member is a cover member, and the antireflective 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 reflection of light incident from the outside of the cover member can be prevented on the incident side, an antireflection effect is better than when the antireflection layer is formed on the part on the emission side which is the inner side of the cover member. Is obtained.

A timepiece according to the present invention includes the above-mentioned translucent member, and the above-mentioned translucent member is provided in a case for housing a timepiece.
The timepiece of the present invention can enjoy the same operation and effect as those 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 characterized by including the sputtering process which forms the high refractive index layer and low refractive index layer which comprise the said reflection prevention layer by sputtering.
According to the present invention, since the antireflective layer is formed by sputtering, it is possible not only to improve the hardness of the entire antireflective layer, as compared to the case of forming the high refractive index layer and the low refractive index layer by simple vapor deposition. Also, the adhesion between the antireflective layer and the base material and the interlayer adhesion in the antireflective layer are excellent. Therefore, as a result, it can contribute to the improvement of abrasion resistance.

Here, when performing the above-mentioned sputtering, it is more preferable than the 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.
In addition, if the reverse sputtering step of removing the deposit on the surface of the substrate is provided before the antireflective layer is formed by sputtering, the substrate surface can be cleaned, so the substrate and the antireflective layer are formed. It is more preferable than the viewpoint of the adhesion improvement with these.

  According to the present invention as described above, it is possible to provide a translucent member having both an antireflective function and scratch resistance, a timepiece provided with the same, 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 cover glass for a watch (hereinafter, also simply referred to as a "cover glass"), and FIG. 1 shows a cross section of the cover glass 1 of the present embodiment. A diagram is shown. The cover glass 1 is provided with a transparent substrate 11 and an antireflective layer 12 formed thereon.

[Material of Base Material 11]
The material of the substrate 11 is an inorganic oxide, and examples thereof include sapphire glass, quartz glass, soda glass and the like. Sapphire glass is particularly preferable as the material of the watch cover glass from the viewpoint of hardness and transparency.

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

The antireflection layer 12 does not have to have four layers, and may have five or more layers. From the viewpoint of enhancing the reflection preventing effect, it is preferable that the number of laminations is large. However, if the number of layers is too large, problems 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, 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. If the thickness range is deviated, the reflectance of the antireflective layer 12 tends to be high.
Here, the surface hardness of the cover glass 1 shown in FIG. 1 is 24000 N / mm ² or more in a measured value in accordance with ISO 14577 using a nano indenter (test load 1.225 mN)
.

[Step of Forming Antireflection Layer 12]
When forming the above-mentioned antireflection layer 12 on the surface of the substrate 11, a sputtering method is suitably used. In addition, a vacuum evaporation method is also applicable, and methods, such as ion beam assistance, can also be used together suitably by a vacuum evaporation method. However, in order to obtain the antireflective layer 12 excellent in hardness, the sputtering method is most preferable. As the sputtering method or the vacuum evaporation method, a usual method used for forming an inorganic thin film can be applied.
Moreover, when performing above-described sputtering, it is more preferable than the 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, if the reverse sputtering process is performed to remove the deposits on the surface of the substrate 11 before the antireflective layer 12 is formed by sputtering, the surface of the substrate 11 can be cleaned. It is more preferable than the viewpoint of the adhesion improvement with 11 and the anti-reflective layer 12.

According to the above embodiment, the following effects can be obtained.
The cover glass 1 is configured to include a transparent substrate 11 and an antireflective layer 12. The antireflective layer 12 is formed by alternately laminating the high refractive index layers 12A and 12C and the low refractive index layers 12B and 12D, and in the range from the outermost surface of the antireflective layer 12 to a depth of 150 nm. The content of silicon nitride is 30 to 50 vol%. Therefore, the surface of the antireflective layer 12 becomes a very hard layer. When the content of silicon nitride in the range up to the predetermined depth is less than 30 vol%, the scratch resistance of the antireflective layer 12 becomes insufficient, and for example, the practicability as a cover glass for a watch becomes poor. In addition, since the content of silicon nitride in the range from the outermost surface of the antireflective layer 12 to the depth of 150 nm is 50 vol% or less, the antireflective effect is also excellent. When the content of silicon nitride in the range up to the predetermined depth exceeds 50 vol%, the antireflective effect is inferior and the practicability as a cover glass for a watch becomes poor. When the content of silicon nitride in the range from the outermost surface of the antireflective layer 12 to the depth of 150 nm is 40 vol% or more, it is possible to further improve the scratch resistance of the antireflective layer while maintaining the antireflective 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 watch or a portable information device. In addition, when the surface hardness is 30000 N / mm ² or more, it is possible to exhibit further excellent scratch resistance.

Second Embodiment
An antifouling layer can be formed on the above-mentioned antireflection layer 12. FIG. 2 shows a cover glass 2 in which an antifouling layer 13 is further formed on the above-described antireflective layer 12. 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 repellent agent / oil repellent agent. As such a compound, a fluorine-containing organic silicon compound such as alkoxysilane is preferable.
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 ₃ ) 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 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 [herein 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'CO
NH (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 S
_{i (OC 2 H 5) 3} , Rf '(CH 2) 2 OCO (CH 2) 2 S (CH 2) 3 Si (OC
_{H 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
Such as _{Si (OCH 2 CH 2 OCH 3} ) 3 and the like. In each of the above-mentioned formulas, Cy is a cyclohexane residue, and Rf 'is a polyfluoroalkyl group having 4 to 16 carbon atoms.

  As the fluorine-containing organic silicon 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, e are integers of 0 or 1, and a + b + c + d + e is at least 1 or more, and the order of existence of each repeating unit enclosed by a, b, c, d, e is There is no limitation on f is 0, 1 or 2; g is 1, 2 or 3; h is an integer of 1 or more.

Wherein, R _f ² is the formula: - wherein the "(C _k F _2k) O-" units represented by a divalent group having a linear perfluoroalkyl polyalkylene ether structure having no branch. In addition, _{k in} a formula: "-( _CkF2k ) O-" is an integer of 1-6. R ³ is a monovalent hydrocarbon group having 1 to 8 carbon atoms, and W is a hydrolyzable group or a halogen atom. p is 0, 1 or 2 and n is an integer of 1 to 5. m and r are 2 or 3;

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

[Step of Forming 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 process)
As a dry method, it is possible to employ a vacuum evaporation method in which the fluorine-containing organosilicon compound is evaporated in a vacuum tank to adhere to the surface of the substrate 11 (antireflection layer 12). 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 a suitable fluorine-based solvent is attached to a fibrous or porous medium, and it is applied in a vacuum tank under a pressure of 1 to 0.0001 Pa. By heating, it adheres on the anti-reflective layer 12 of the cover glass 2 mounted in the inside of a vacuum tank, and the antifouling layer 13 is formed. As a fluorine-type solvent to be used, the same thing as what is used by the wet method mentioned later can be used. The amount of solvent used is small and there is almost no environmental impact.

As such a medium, conductive fibers and porous sintered metals are preferable from the viewpoint of thermal conductivity and heating efficiency, and copper and stainless steel are preferable as the 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 the time of heating the fluorine-containing organosilicon compound attached to the medium at the time of forming the antifouling layer 13 varies depending on the pressure in the vacuum tank, but is set within a range not exceeding the decomposition temperature of the organosilicon compound. Is preferred.

  The pressure at the time of forming the antifouling layer 13 is preferably 0.5 to 0.005 Pa, and 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 mean free path of the evaporation molecules is short, and the forming speed of the antifouling layer 13 is reduced. On the other hand, if the pressure is lower than 0.0001 Pa, although the formation rate of the antifouling layer 13 is increased, it takes too much time to obtain such a vacuum state, which is also not preferable.

The formation rate (deposition rate) of the antifouling layer 13 is preferably 0.05 to 5.0 Å / s, and more preferably 0.1 to 2.0 Å / s. If it is less than 0.05 Å / s, the production cost is too high because the productivity is low. When the thickness exceeds 2.0 Å / s, the layer thickness distribution of the antifouling layer 13 becomes uneven, and the surface slipperiness deteriorates. Here, the formation rate of the antifouling layer 13 can be controlled by adjusting the pressure in the vacuum chamber and the heating temperature.
In the vacuum evaporation 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 (the antireflective layer 12) by a wet method, any of the above-mentioned fluorine-containing organic silicon compounds is dissolved in an organic solvent to obtain a predetermined concentration. It is possible to adopt a method of adjusting to and coating on the surface of the substrate 11. The organic solvent is preferably an organic compound having a perfluoro group excellent in the solubility of the fluorine-containing organic silicon compound and having 4 or more carbon atoms, for example, perfluorohexane, perfluorocyclobutane, perfluorooctane, perfluorodecane And perfluoromethylcyclohexane, perfluoro-1,3-dimethylcyclohexane, perfluoro-4-methoxybutane, perfluoro-4-ethoxybutane and metaxylene hexafluoride. In addition, perfluoroether oil, chlorotrifluoroethylene oligomer oil can be used. In addition, fluorocarbon 225 (CF ₃ CF ₂ CHCl ₂ and CClF ₂ CF ₂ CHClF
(A mixture of These organic solvents can be used alone or in combination 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 the amount is less than 0.03% by mass, it may be difficult to form the antifouling layer 13 having a sufficient thickness, and a sufficient water repellency / oil repellency effect and a sufficient slipperiness may not be obtained. On the other hand, if the concentration is more than 1% by mass, the antifouling layer 13 may be too thick, and the load of the rinse operation for eliminating coating unevenness after application may be increased.

<Coating process>
As a coating method, a dipping method, a spin coating method, a spray method, a flow method, a doctor blade method, roll coating, gravure coating, curtain flow coating, brush coating, or the like is used. The layer thickness of the antifouling layer 13 is not particularly limited, but preferably 0.001 to 0.05 μm, more preferably 0.001 to 0.03 μm, and still more preferably 0.001 to 0.02 μm. preferable.
If the thickness of the antifouling layer 13 is less than 0.001 μm, sufficient water repellency and oil repellency can not be exhibited, and the slipperiness is also inferior, so that the abrasion resistance and the chemical resistance may be reduced. In addition, if the thickness of the antifouling layer exceeds 0.05 μm, the surface hardness of the cover glass 2 may be reduced, and the surface light scattering by the antifouling layer 13 becomes large, so the transparency of the substrate 11 is inhibited. There is a fear.

  In the case of the dipping method, the substrate 11 is immersed in a treatment liquid adjusted to a predetermined concentration using the above-mentioned organic solvent, and after a certain time, the substrate 11 is pulled up at a constant speed. At this time, the immersion time is preferably about 0.5 minutes to 3 minutes. If the time is less than 0.5 minutes, the adsorption of the fluorine-containing organic silicon compound on the surface of the base material 11 is not sufficient, so that it is not possible to obtain predetermined water / oil repellent performance and slipperiness. If it exceeds 3 minutes, the cycle time is undesirably increased. The pulling speed is preferably 100 mm / min to 300 mm / min. This is determined in view of the concentration of the treatment liquid, but if it is less than 100 mm / min, the antifouling layer 13 becomes too thin to obtain predetermined performance, and if it exceeds 300 mm / min, the antifouling layer 13 may be too thick, which may increase the burden of the rinse operation to eliminate coating unevenness after application.

Aging Process
After the application step, it is left for 0.5 hours or more in an atmosphere at a temperature of 10 to 60 ° C. and a relative humidity of 10 to 90%. The temperature is preferably 20 to 50 ° C., and the relative humidity is preferably 20 to 80%. The standing time (aging time) is preferably 1 to 10 hours. When the ambient temperature is too low, the reactivity of the organosilicon compound is low, so that the formation of the antifouling layer 13 is insufficient. On the contrary, if the ambient temperature is too high, the antifouling layer 13 may be cracked and the appearance of the cover glass 2 may be poor. When the atmospheric humidity is too low, the reactivity of the organosilicon compound is low as in the case of the temperature, so that the formation of the antifouling layer 13 is insufficient. If the atmospheric humidity is too high, the reaction is too fast, and the antifouling layer 13 may be cracked to cause the appearance of the cover glass 2 to be defective. When the aging time is too short, the reaction of the organosilicon compound becomes insufficient, and the formation of the antifouling layer 13 becomes insufficient. As the ripening time, 0.5 hours or more is required. For example, 25 ° C., relative humidity 40% about 24 hours, 60 ° C., relative humidity 80% about 2 hours is preferable.
In any of the above-described dry method and wet method, it is preferable to perform plasma treatment (argon, oxygen, etc.) on the surface of the antireflective layer 12 in advance. When the plasma treatment is performed on, for example, the antireflective layer 12 (low refractive index layer 12D, SiO ₂ layer), the adhesion (adhesiveness) between the antireflective layer 12 and the antifouling layer 13 is greatly improved. 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 according to ISO 14577 using a nano indenter (test load: 1.225 mN).

According to the above embodiment, the following effects can be obtained.
An antifouling layer 13 made of a fluorine-containing organic silicon compound is formed on the antireflective layer 12. Therefore, the antifouling layer not only exhibits the water and oil repellency but also is extremely excellent in surface slipperiness. Therefore, even if an external impact is applied to the cover glass 2, the impact can be softened by the slipperiness of the surface of the antifouling layer 13, so 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 formulas (1) and (2) described above as the fluorine-containing organic silicon compound used for the antifouling layer 13, the cover glass 2 is provided with high slip properties. 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, a cover glass which can exhibit sufficient water and oil repellency and is excellent also in scratch resistance and chemical resistance Can provide
Since the surface hardness of the cover glass 1 is 24000 N / mm ² or more, sufficient abrasion resistance can be obtained when applied to a watch, a portable information device, or the like.

When the antifouling layer 13 is formed by the above-described predetermined wet method, not only can the cover glass 2 having excellent scratch resistance be manufactured, but large equipment such as a vacuum device is not necessary, and the cost for manufacturing can be reduced. It becomes possible.
In addition, when the antifouling layer 13 is formed by the above-described predetermined dry method, not only can the cover glass 2 having excellent scratch resistance be manufactured, but also the solvent is not substantially used, so the environmental load is low. 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 also high by using a fibrous or porous medium.

The present invention is not limited to the embodiments described above, and various improvements and modifications can be made as long as the object of the present invention can be achieved.
In the said embodiment, although the example to which this invention was applied to the cover glass 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 mechanical watches and the like, a translucent member as a cover member is provided at the position where the back cover is provided, and the see-through back specification allows the internal mechanism of the timepiece to be visually recognized through the translucent member. Sometimes. In such a case, the present invention can be applied to this translucent member.
In addition, although sapphire glass with high hardness is suitable as a base material of a translucent member, use of quartz glass, soda glass, etc. may be examined besides this.

The translucent member of the present invention is not limited to the cover member used in a watch, and covers the information display unit in various devices such as mobile phones, portable information devices, measuring devices, digital cameras, printers, diving computers, and pulsimeters. It can be suitably used as a member.
In addition, the translucent member of this invention is not limited to a cover member. The antireflective layer and the antifouling layer according to the present invention are formed on the base material of the light transmitting member at any place where the hardness is secured, the antireflective function and the scratch resistance are required.

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

[Examples 1-16, Comparative Examples 1-12]
(Pretreatment of base material 11)
After immersing the sapphire glass in hot concentrated sulfuric acid at 120 ° C. for 10 minutes, the sapphire glass was thoroughly washed with pure water, and dried in the air for 30 minutes in the atmosphere set at 120 ° C. Next, the sapphire glass was placed inside a sputtering apparatus, and then 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 reverse sputtering was performed at 0.8 mTorr to clean the sapphire glass surface.

(Formation of antireflective layer 12)
Using silicon as a target, sputtering was performed under the following conditions to form an antireflection layer 12 (four to nine layers) composed of a high refractive index layer and a low refractive index layer on the surface of the sapphire glass substrate 11. Specific layer configurations are shown in Tables 1 and 2. The volume fraction of silicon nitride (SiN x) from the outermost surface of the antireflective layer 12 to the depth of 150 nm is shown as the SiN x occupancy.
High refractive index layer: silicon nitride (SiN x)
N ₂ gas: 10.0 sccm
Ar gas: 10.0 sccm
Sputtering power: 2.0 KW
Low refractive index layer: silicon oxide (SiO ₂ )
0 ₂ gas: 10.0 sccm
Ar gas: 10.0 sccm
Sputtering power: 1.5 KW

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

(2) Light transmittance difference (ΔT%) before and after sand fall test
First, the following sand fall test is conducted. Position the cover glass at an inclination angle of 45 ° with respect to the horizontal plane. At this time, the cover glass is disposed such that the side on which the antireflective layer 12 is formed is on the top side. Then, sand is dropped toward the antifouling layer from a height of 1 m from the horizontal surface. After that, the cover glass was washed, and the scratch resistance 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 material of the sand to be used is carborundum produced by crushing and classifying a black silicon carbide ingot and a green silicon carbide ingot. In this test, 800 cm ³ of Carborundum # 24 having a central particle size of 600 to 850 μm was used.

(3) Surface hardness (N / mm ² )
The surface hardness of the antireflective layer side of the substrate 11 at a test load of 1.225 mN was measured using a nanoindenter (in accordance with ISO 14577).

〔Evaluation results〕
From the results of Table 1, regardless of the number of layers of the antireflective layer 12, maintaining the surface hardness at 24000 N / mm ² or more by setting the occupancy rate of SiN x to 30 to 50 vol% from the outermost surface to a depth of 150 nm. At the same time, it can be seen that the difference in transmittance (.DELTA.%) Before and after the sand fall test can be made 2% or less. When the difference in transmittance is 2% or less, it can be said that the practical scratch resistance as a watch cover glass is good. Moreover, the transmittance | permeability difference before and behind a sand falling test can be further made into 1.5% or less by making SiNx occupancy rate into 40 vol% or more. If the transmittance difference is 1.5% or less, it can be said that practical scratch resistance is extremely good.
On the other hand, according to 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 it is practically used It turns out that it will be a difficult level. Further, as shown in Comparative Examples 2, 4, 6, 8, 10 and 12, when the SiNx occupancy rate is less than 30 vol%, the surface hardness becomes very small and the transmittance difference also becomes large. That is, it becomes inferior to scratch resistance.

[Examples 17 to 22]
About the above-mentioned Example 1, 3, 5, 8, 11, 14, the antifouling layer 13 was further formed in the surface of the reflection prevention layer 12, and evaluation was performed similarly.
(Formation of antifouling layer 13)
A compound containing 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 give a solid content of 3 mass% is Japan Steel Wool # 0, wire diameter 0.025 mm) 1.0 g filled in a container (cylindrical copper container with an open top, inner diameter 16 mm x inner height 6 mm) pre-filled with 0.5 g And dried at 120 ° C. for 1 hour. Next, this copper container is placed in a vacuum evaporator together with sapphire glass on which an antireflective layer is formed, and the pressure in the apparatus is set to a pressure of 0.01 Pa. The fluorine-containing organosilicon compound was evaporated from the copper container so as to obtain a film formation rate (deposition rate) of s. A molybdenum resistive heating boat was used as a heating source.

(Evaluation of characteristics of cover glass 2)
The characteristics described above were evaluated for the cover glass 2 manufactured under the above-described manufacturing conditions. The results are shown in Table 3.

〔Evaluation results〕
As shown in Table 3, the cover glasses 2 of Examples 17 to 22 all have an antifouling layer, but the cover glasses 1 serving as the bases thereof (Examples 1, 3, 5, 8, 11) And 14), it can be seen that the antireflective effect and the scratch resistance are excellent. That is, it can be seen that the effect of the SiNx occupancy ratio is strongly reflected even if the antifouling layer is formed.

1, 2 ... cover glass (light transmitting member, cover member), 11 ... substrate, 12 ... antireflective layer, 12A, 12C ... high refractive index layer, 12B, 12D ... Low refractive index layer, 13 ... antifouling layer

Claims (13)

It is a cover member provided with the base material which has translucency,
At least a portion of the surface of the substrate
A laminate as an antireflective layer comprising a layer comprising silicon nitride and a layer comprising silicon oxide,
In the stack, the content of silicon nitride in the range from the outermost surface to a depth of 150 nm is 30 to 50 vol%,
The surface of the laminate has an antifouling layer containing a fluorine-containing organosilicon compound,
The cover member is provided on a mechanical watch. In the cover member according to claim 1,
The cover member is provided to a see-through mechanical watch. The cover member according to claim 1 or 2
The cover member is provided on a back cover of the mechanical watch. The cover member according to any one of claims 1 to 3.
The cover is characterized in that the content of the silicon nitride in the range from the outermost surface to the depth of 150 nm is 40 to 50 vol%. The cover member according to any one of claims 1 to 4.
The thickness of the said antifouling layer is 0.001-0.05 micrometers. The cover member characterized by the above-mentioned. The cover member according to any one of claims 1 to 5.
The surface hardness of the cover member is 24000 N / mm ² or more. The cover member according to any one of claims 1 to 6.
The cover member is characterized in that the number of laminated layers is four by laminating the layer containing silicon nitride and the layer containing silicon oxide. The cover member according to any one of claims 1 to 7.
The cover member, wherein the base material is sapphire glass. The cover member according to any one of claims 1 to 8.
The surface hardness of the cover member is 30000 N / mm ² or more. The cover member according to any one of claims 1 to 9.
The cover member, wherein the fluorine-containing organosilicon compound is an alkoxysilane compound. The cover member according to any one of claims 1 to 10.
The cover member wherein the fluorine-containing organic silicon compound is a perfluoroether compound represented by at least one of the following formulas (1) and (2).

(Wherein 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 water) R ² represents hydrogen or an inactive monovalent hydrocarbon group, a, b, c, d and e each represent an integer of 0 or more, and a + b + c + d + e is at least 1 or more. The order in which each repeating unit enclosed by a, b, c, d and e is present is not limited in the formula, f is 0, 1 or 2, g is 1, 2 or 3. h is It is an integer of 1 or more.)

(Wherein, R _f ² represents a divalent group having a linear perfluoropolyalkylene ether structure having no branch, containing a unit represented by the formula: “— (C _k F _{2 k} ) O—” Note that _k in the formula “— (C _k F _{2 k} ) O—” is an integer of 1 to 6. R ³ is a monovalent hydrocarbon group having 1 to 8 carbon atoms, and W is hydrolyzable. Group represents a halogen atom, p is 0, 1 or 2, n is an integer of 1 to 5. m and r are 2 or 3.) The cover member according to any one of claims 1 to 11.
The cover member is characterized in that the lamination is formed on at least an outer portion of an inner portion and an outer portion of the cover member. A mechanical timepiece comprising the cover member according to any one of claims 1 to 12.

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