WO2008050500A1

WO2008050500A1 - Protective plate for portable equipment display device

Info

Publication number: WO2008050500A1
Application number: PCT/JP2007/057482
Authority: WO
Inventors: Masahiro Kobayashi; Koichi Hashimoto
Original assignee: Nippon Electric Glass Co., Ltd.
Priority date: 2006-09-29
Filing date: 2007-04-03
Publication date: 2008-05-02

Abstract

This invention provides a protective plate for a portable equipment display device, characterized by comprising a plate glass having a Young's modulus of not less than 75 GPa. Further, the protective plate for a portable equipment display device is characterized by comprising a plate glass having a composition comprising, by mass, 50 to 80% of SiO2, 15 to 30% of Al2O3, and 15 to 30% of Al2O3 + MgO + ZnO. The protective plate for a portable equipment display device is usable as protective plates for displays for cellular phones, digital cameras, and PDAs, as well as for displays, for example, for portable gaming machines, portable music players, IC recorders, and electronic dictionaries.

Description

Specification

Protection plate for portable device display device

Technical field

[0001] The present invention relates to a protective plate for protecting a display device of a portable device from isotropic force.

Background art

In recent years, mobile devices, particularly mobile phones, digital cameras, and personal digital assistants (PDAs) have been reduced in size, weight, and thickness. On the other hand, these displays are becoming larger. Liquid crystal displays (LCD) and organic EL displays (OELD) are mainly used for such displays.

[0003] These displays are more susceptible to impacts and external forces in handling than displays that are fixed and used, such as monitors of televisions and personal computers. For example, when external force is applied to the LCD, image disturbance called “paddling” may occur or the glass substrate may be damaged. Therefore, in order to protect the display, a transparent resin plate (protective plate) is installed in parallel with the display via a fixed width interval (see, for example, Patent Document 1).

) o

[0004] However, when the resin board is used for a long period of time, the resin deteriorates and the transparency is lowered, or the surface is soiled or scratched, resulting in a problem that the display becomes visible. . That you use to protect plate glass plate has been proposed in order to solve such problem instead of榭脂plate (e.g., see Patent Document 2.) ₀

Patent Document 1: Japanese Patent Application Laid-Open No. 2004-299199

Patent Document 2: Japanese Patent Laid-Open No. 2003-140558

Disclosure of the invention

[0005] As described above, a protective plate that also has glass power is required to have low transparency and be less susceptible to dirt and scratches. However, in recent years, the protective plate itself is becoming increasingly thin for portable devices. It is required to reduce the wall thickness.

[0006] However, if the thickness of the protective plate made of glass is reduced, the protective plate tends to break and Does not function as a protective plate.

[0007] An object of the present invention is to provide a protective plate for a portable device display device that can sufficiently protect the display even when the wall thickness is reduced.

[0008] As a result of intensive studies, the inventors of the present invention have a particularly large amount of Al 2 O (15 to 30%) in the glass composition.

twenty three

When added, it is found that the glass plate becomes difficult to squeeze, and the effect of chemical strengthening becomes high and it is difficult to break, which is proposed as the present invention.

That is, the present invention relates to the following (1) to (6).

(1) A protective plate for a portable device display device, comprising a plate glass having a Young's modulus of 75 GPa or more.

(2) The protective plate for a portable device display device according to (1), wherein the plate glass is physically strengthened or chemically strengthened.

(3) The protective plate for a portable device display device according to (1) or (2), wherein the plate glass has a surface compressive stress value of 700 MPa or more.

(4) The protective plate for a portable device display device according to any one of (1) to (3), wherein a scattering prevention film is adhered to the surface of the plate glass.

(5) By mass%, SiO 50-80%, Α1 Ο 15-30%, Al O + MgO + ZnO

2 2 3 2 3

A protective plate for a portable device display device, comprising a plate glass containing a composition of 15 to 30%.

(6) Sheet glass is in mass%, SiO 50-80%, Α1 Ο 15-30%, Α1 Ο + Μ

The protective plate for a portable device display device according to any one of claims 1 to 4, which also has a glass strength containing a composition of 2 2 3 2 3 gO + ZnO 15 to 30%.

[0009] Since the protective plate for a portable device display device of the present invention includes a plate glass having a Young's modulus of 75 GPa or more, it is difficult to squeeze and break even if it is thin. As a result, since the display can be sufficiently protected even if the wall thickness is reduced, the mobile device itself can be made thinner.

BEST MODE FOR CARRYING OUT THE INVENTION

[0010] Hereinafter, the present invention will be described in detail. The percentages and the like in this specification are based on mass unless otherwise indicated. All hundreds defined by mass The fractions and the like are the same as those defined by weight.

[0011] The Young's modulus of the plate glass is 75 GPa or more, and preferably 78 GPa or more, more preferably 80 GPa or more.

[0012] The protective plate for a portable device display device of the present invention is preferably such that the hardness of the plate glass is 500 Hv or more, since the surface is hardly scratched, so that it does not cause breakage and the display is difficult to see. More preferably, it is 600 Hv or more, and further preferably 650 Hv or more.

The protective plate for a mobile device display device of the present invention has a thermal expansion coefficient of 30 to 70 10 ^_7 7 °, preferably 35 to 60 10 ^_7 7 °, more preferably 40 to 30 in the range of 30 to 380 ° C. 50 X 1 0 ^_ . C. When the thermal expansion coefficient is higher than 70 ^× 10 ^_7 / ° C, the glass substrate is easily damaged by thermal strain when immersed in a molten salt such as potassium nitrate. If the thermal expansion coefficient is smaller than 30 X 10 ^_7 Z ° C, the thermal expansion coefficient cannot be matched with the surrounding members.

[0013] The protective plate for a portable device display device of the present invention is preferable because it is damaged when it is strengthened. In particular, a sheet glass having a surface compressive stress value of 700 MPa or more is preferred because of its excellent effect of preventing breakage.

[0014] Methods for strengthening the protective plate include a method of rapidly cooling from a temperature above the strain point (physical strengthening) and an alkali metal ion (for example, Li + or Na +) contained in the protective plate with an alkali having a large ion radius. A method of ion exchange with metal ions (for example, K +) (strengthening of chemicals) is widely used. However, the method of ion exchange is preferable because it can apply a large compressive stress to break.

[0015] When the protective plate for a portable device display device of the present invention has an antireflection film formed on at least one side (particularly the outer surface side), there is less reflection and images and images on the display device are easy to see. preferable.

In addition, when a transparent conductive film is formed on the protective plate for a portable device display device of the present invention, it is possible to shield electromagnetic waves and to prevent contamination such as dust because it is difficult to be charged. As the transparent conductive film, oxides such as tin-containing indium oxide (ITO), antimony-containing indium oxide, and fluorine-containing indium oxide, and metal thin films such as aluminum, gold, and silver can be used.

[0017] The protective plate for portable device display device of the present invention is formed with a scattering prevention film (scattering prevention film). It is preferable that fragments are hardly scattered even if the plate glass is broken. The anti-scattering film is preferred because it has an excellent effect of preventing debris from being scattered on either side, even if it is formed on either side.

[0018] The protective plate for a portable device display device of the present invention is expressed by mass%, SiO 50-80%, Al 2 O 3

twenty two

When made of glass containing a composition of 15-30%, AI O + MgO + ZnO 15-30%

3 2 3

The Young's modulus is large and difficult to stagnate.

[0019] SiO is a component that forms a skeleton of glass. If it is less than 50%, weather resistance is obtained.

2

If it exceeds 80%, the viscosity of the glass tends to increase and melting tends to be difficult, and the liquidus temperature rises, making it difficult to form. Therefore, SiO

The content of 2 is 50 to 80%, preferably 50 to 75%, more preferably 55 to 75%, more preferably 60 to 70%, and still more preferably 62 to 68%.

[0020] Al O increases the Young's modulus and facilitates ion exchange to strengthen the surface.

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It is also a component that can increase the compressive stress value. If the amount is less than 15%, the above effect tends to be difficult to obtain.If the amount is more than 30%, the viscosity of the glass becomes high, so that it becomes difficult to melt, and the liquidus temperature rises to make molding difficult. Cheap. Therefore, Al O

The content of 2 3 is 15 to 30%, preferably 17 to 28%, more preferably 20 to 25%.

[0021] Al 2 O, MgO, and ZnO are components that increase the Young's modulus. 15% total content of these ingredients

twenty three

If the ratio is less than 33%, the Young's modulus cannot be sufficiently increased, and if it is more than 33%, it tends to be difficult to melt or devitrification is likely to occur. Therefore, Al O, Mg

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0, the total amount of ZnO is 15 to 33%, preferably 15 to 30%.

[0022] MgO is not an essential component, but can be added up to a content of 5%. If it exceeds 5%, devitrification occurs and it is difficult to mold immediately. A content of 4% or less is preferred 3.5

It is more preferable that it is% or less.

[0023] ZnO is not an essential component, but can be added up to a content of 5%. If it exceeds 5%, devitrification tends to occur. The content is preferably 4% or less, and more preferably 3.5% or less.

In addition to the above, the following components can be added. [0025] Li 2 O is an ion exchange component that improves meltability, increases Young's modulus,

2

It is a component that adjusts the tension coefficient and can be added up to 6%. If the content is more than 6%, the glass tends to be devitrified or it may become cloudy due to phase separation. In addition, the coefficient of thermal expansion becomes too high, and there is a risk that the glass will break easily when immersed in molten potassium nitrate during ion exchange. The content is preferably 5.5% or less, and more preferably 5.2% or less. On the other hand, from the viewpoint of improving the Young's modulus and ion exchange performance of the glass, it is preferable to contain 0.1% or more of Li 2 O, and more preferably 0.5% or more.

2

More preferably, it is 1% or more.

[0026] Na 2 O is also an ion exchange component, improving the meltability and adjusting the thermal expansion coefficient.

2

It can be added up to 5%. If the content is more than 5%, the Young's modulus may decrease, and when a transparent conductive film such as an ITO film is formed on the glass surface, the transparent conductive film is likely to deteriorate, which is not preferable. The content is preferably 4.5% or less. 4. More preferably, the content is 2% or less.

[0027] Li O and Na 2 O are components strengthened by ion exchange with K +,

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0.1% or more is preferable 0.5% or more is more preferable 1% or more is more preferable. If it is less than 1%, it is not preferable because it is difficult to sufficiently strengthen even after ion exchange with K +.

[0028] K 2 O is a component that enhances the meltability and increases the coefficient of thermal expansion.

2

can do. If the content is more than 5%, the Young's modulus may decrease, which is not preferable. The content is preferably 4.5% or less. 4. More preferably, the content is 2% or less.

The total amount of Li 0, Na 2 O and Κ Ο is 0-10%. The total amount of these becomes 10% or more

2 2 2

When the ion exchange is performed because the glass has a too high thermal expansion coefficient, the glass is likely to break due to thermal strain, which may reduce productivity. Preferred Li 0, Na O and

The range of the total amount of 2 2 and K Ο is 0 to 8%, more preferably 0.1 to 8%,

2

A preferred range is 0.5 to 8%, and a particularly preferred range is 1 to 7%.

[0029] CaO, SrO, and BaO are also components that increase the meltability and easily cause force devitrification. Therefore, these components can be added up to 8% in total. 7% or less 6. It is more preferable that it is 6.5% or less.

[0030] TiO is a component that lowers the glass viscosity at high temperatures and imparts weather resistance,

2

It is a component that easily causes devitrification and can be added up to 8%. It is preferably 6% or less, more preferably 4% or less.

[0031] ZrO is a component that imparts weather resistance, but is easily devitrified and difficult to melt

2

However, up to 7% can be added. 5% or less is preferred 4% or less is more preferred

[0032] PO is a component that suppresses the occurrence of devitrification, and is easy to phase-separate!

twenty five

Can be added. 5% or less is preferable 4% or less is more preferable.

[0033] As O, Sb 2 O, Sb 2 O, SO, Cl, F may be added up to 2% each as a clarifier.

2 3 2 3 2 5 3

However, it is preferable not to contain As O because it is an environmentally hazardous substance.

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[0034] Content of colored oxides such as Fe 2 O, CuO, CoO, Cr 2 O, NiO, etc. is 1% or less in total

2 3 2 3

It is preferable that The total content is more preferably 0.7% or less, and even more preferably 0.5% or less.

Example

Hereinafter, the present invention will be described in detail using examples and comparative examples.

[0036] Table 1 shows the glass composition and properties of each sample, Table 2 shows the amount of stagnation of each sample, and Table 3 shows the properties before and after chemical strengthening.

[0037] [Table 1]

Example 1 Example 2 Comparative example 1 Comparative example 2 Material Glass Glass Glass acrylic

S i O ₂ (wt%) 66.0 65.6 67.0

A 1 ₂ O 3 22.0 22.0 6.0

L i ₂ O 4.0 4.0 ―

N a 2 O 0.5 0.4 14.0

K ₂ O 0.5 0.5 2.0

M g O ― 0.8 3.0

C a O ― ― 7.5

S r O ― ― ―

B a O 0.5 0.2 ―

Z n O ― ― 0.5

T i O 2 2.0 2.0 ―

Z r O ₂ 2.0 2.0 ―

P 2 O ₅ 1.5 1.5-

S b a O a 1.0 1.0 ―

Young's modulus (GPa) 81 82 70 3.0 Hardness (Hv) 700 710 640

Average transmittance (%) 91.4 91.0 91.5 92 Density (g / cm ³ ) 2.4 2.4 2.5 1.2 Thermal expansion coefficient

44 44.5 93.6 ―

(1 0 one ^{^7/0} C)

Example 1 Example 2 Comparative example 1 Comparative example 2 Substrate size Deflection amount (mm) Deflection amount (mm) Manipulation amount (mm) Deflection amount (mm)

25 x 35 x 1.0 mm 0. 01 0. 01 0. 01 0. 3

50 x 70 1 .O m m 0. 05 0. 05 0. 06 1. 3

25 x 35 x 0.7 m m 0. 03 0. 03 0. 04 0. 9

50 x 70 x 0.7 mm 0. 1 4 0. 1 4 0. 1 7 3. 8

25 35 x 0.4 mm 0. 1 7 0. 1 7 0. 20 Not measured

50 X 70 X 0.4 m m 0. 76 0. 75 0. 88 Not measured

[0039] [Table 3]

[0040] Each sample (Example and Comparative Example 1) was produced as follows.

[0041] First, glass raw materials were prepared so as to have the composition shown in Table 1, and then charged into a platinum crucible.

The molten glass was obtained using an electric furnace at 1600 ° C for 5 hours.

[0042] Next, the molten glass was poured onto a carbon plate, and a glass plate having a thickness of 1.2 mm was produced using a roller.

[0043] Finally, after annealing at 650 ° C, the surface was optically polished to prepare a sample.

[0044] The Young's modulus was measured by a resonance method by preparing a sample of 20 X 40 X 1 mm. The measuring device used was a nondestructive elastic modulus measuring system (Kanebo KI-11).

[0045] The hardness was measured 10 times using a micro hardness tester (MXT-50 manufactured by Matsuzawa Seiki Co., Ltd.), and the average was calculated.

[0046] The average transmittance was 40 x 40 x 0.7 mm, and the transmittance at each wavelength of 400 to 700 nm was measured using a spectrophotometer (Shimadzu UV-3100PC) with a slit width of 2n. Measured in m and averaged.

[0047] The density was measured by the well-known Archimedes method. The thermal expansion coefficient was measured using a dilatometer, and the average thermal expansion coefficient at 30 to 380 ° C was used.

[0048] Next, the amount of stagnation was measured as follows.

[0049] First, each sample shown in Table 2 was prepared and arranged on a frame in which each side of the sample was supported with a width of lmm.

[0050] Next, an ION load was measured in a direction perpendicular to the sample surface with a rod having a square cross section of 10 mm x 10 mm in the center of the sample, and the amount of displacement at the center was measured as the amount of stagnation.

[0051] Next, five samples of 35 x 35 x 0.70 mm were prepared for the samples of Example and Comparative Example 1, respectively, and immersed in a potassium nitrate melt under the conditions shown in Table 3.

[0052] Using a surface stress meter (FSM-60 manufactured by Toshiba), it was confirmed that a compressive stress layer was formed on the sample surface, and the compressive stress value and the depth thereof were measured.

[0053] Also, the immersed sample was placed on a smooth ring with an inner diameter of 25 mm, and a load was applied to the center of the sample using a flat indenter with a diameter of 12.5 mm until it was damaged. Was calculated as the average fracture strength.

As is clear from Table 1, the Young's modulus of Example 1 was 81 GPa, the Young's modulus of Example 2 was 82 GPa, and Comparative Example 1 was 70 GPa.

[0055] Further, as is apparent from Table 2, in the same size sample, the stagnation amount of the example was smaller than that of Comparative Example 1! /. For this reason, since the embodiment can reduce the thickness of the sample itself or the distance from the display, it is effective for reducing the thickness of the portable device.

[0056] As is clear from Table 3, Example 1 and Example 2 after strengthening had higher average fracture strength than Comparative Example 1 after strengthening.

For Example 1 and Comparative Example 1, a 35 × 35 × 0.5 mm plate-like sample was immersed in molten potassium nitrate set at 500 ° C. All the end surfaces of these plate samples were polished with # 600 water-resistant abrasive paper, and both surfaces were optically polished. In addition, the time until one plate-like sample was completely immersed in potassium nitrate molten salt was within 1 second, and the number of damaged plate samples for Example 1 and Comparative Example 1 was examined. As a result, in Example 1, the number of damaged sheets was 0 out of 50 sheets, whereas in Comparative Example 1, the number of damaged sheets was 5 out of 50 sheets. there were.

[0057] Although the invention has been described in detail with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention. This application consists of a Japanese patent application filed on October 3, 2005 (Japanese Patent Application 2005-289490) and a Japanese patent application filed on September 29, 2006 (Japanese Patent Application 2006-268 391). Which is incorporated by reference in its entirety.

Also, all references cited herein are incorporated as a whole.

Industrial applicability

[0058] The protective plate for a portable device display device of the present invention can be used as a protective plate for displays such as portable game machines, portable music players, IC recorders, electronic dictionaries, etc., which can be used only with a mobile phone, a digital camera, or a PDA. is there.

Claims

The scope of the claims

[1] A protective plate for a portable device display device, comprising a plate glass having a Young's modulus of 75 GPa or more.

[2] The protective plate for a mobile device display device according to [1], wherein the plate glass is physically strengthened or chemically strengthened.

[3] The surface compressive stress value of the plate glass is 700 MPa or more, or 1

2. A protective plate for a portable device display device according to 2.

[4] The protective plate for a portable device display device according to any one of claims 1 to 3, wherein an anti-scattering film is adhered to the surface of the plate glass.

[5] SiO 50-80%, Α1 Ο 15-30%, Al 2 O + MgO + ZnO 15

2 2 3 2 3

A protective plate for a portable device display device, comprising a plate glass containing a composition of -30%.

[6] Sheet glass is expressed in mass%, SiO 50-80%, Α1 Ο 15-30%, Al O + MgO +

2 2 3 2 3

The protective plate for a portable device display device according to any one of claims 1 to 4, wherein the protective plate has a glass strength containing 15-30% of ZnO.