JP2015099171A - Glass for electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide glass for an electronic apparatus, which achieves weight saving and enhancement of edge strength.SOLUTION: Glass for an electronic apparatus includes a thin wall part forming a central region of the glass, and a thick wall part which forms a peripheral region surrounding the central region and which is thicker than the thin wall part.

Description

  The present invention relates to glass for electronic devices.

In recent years, mobile devices such as smartphones and tablet PCs are rapidly spreading as mobile electronic devices, and the development of cover glasses mounted on these mobile devices is progressing (for example, Patent Document 1).
In addition, as stationary electronic devices such as home televisions, display devices such as liquid crystal displays (LCDs) and plasma displays (PDPs) are becoming larger, and cover glasses and glass used for display devices are also being developed. The size of the substrate is also increasing.

Special table 2011-510904 gazette

Since portable devices are always carried and used by people, there is a strong demand for weight reduction. Therefore, the cover glass mounted on the portable device tends to be thin in order to realize a slight weight reduction.
Also in display devices, attempts have been made to reduce the thickness of the glass used as much as possible, and to realize weight reduction and space saving of the entire device.

  However, as the plate thickness of the glass is reduced, the energy required for breaking the glass is lowered and the glass strength is deteriorated. In particular, the edge of glass tends to be subjected to a strong impact due to its sharp shape, and tends to be a crack starting point. For example, since a portable device is portable, it is susceptible to impacts from various directions, and there is a high demand for enhancing edge strength.

  This invention is made | formed in view of the above point, and it aims at providing the glass for electronic devices by which weight reduction and reinforcement | strengthening of edge strength were implement | achieved.

As a result of intensive studies to achieve the above object, the inventors have made the central region of the glass a thin portion with a relatively thin plate thickness, while the peripheral region has a thick plate portion with a relatively large plate thickness. As a result, it was found that weight reduction and edge strength enhancement could be realized, and the present invention was completed.
That is, the present invention provides the following (1) to (6).

  (1) Glass for electronic equipment, comprising: a thin-walled portion constituting the central region of the glass; and a thick-walled portion constituting a peripheral region surrounding the central region and thicker than the thin-walled portion. Glass.

  (2) The glass for electronic equipment according to (1), wherein the thick part is configured by laminating a plurality of glass plates.

  (3) The glass for electronic devices according to (2), wherein the plurality of glass plates have different glass compositions.

  (4) The glass for electronic devices according to any one of (1) to (3) above, which has a chemically strengthened layer on the surface of which compressive stress is generated by a chemical strengthening treatment.

  (5) In (4), the angle formed by the end surface on the central region side in the thick portion and the surface of the thin portion connected to the end surface is 90 degrees or more and less than 180 degrees in a cross-sectional view. The glass for electronic devices as described.

  (6) The end surface on the central region side in the thick part is curved in a concave shape in a cross-sectional view and is connected to the surface of the thin part, according to any one of (1) to (5). Glass for electronic equipment.

  ADVANTAGE OF THE INVENTION According to this invention, the glass for electronic devices by which weight reduction and reinforcement | strengthening of edge strength were implement | achieved can be provided.

It is a top view which shows an example of the glass 1 typically. It is a sectional side view which shows an example of the glass 1 typically. 4 is a side sectional view schematically showing another example of the glass 1. FIG. It is side sectional drawing which shows typically an example of the glass 1 comprised by the laminated | stacked several glass plate. It is a sectional side view which shows typically an example of the glass 1 to which the chemical strengthening process was performed. It is side sectional drawing which shows an example of the glass 1 which the end surface 12a curves to concave shape in sectional view, and is connected to the surface 11a.

First, as the “electronic device” in the present invention, for example, a mobile electronic device represented by a mobile device such as a smartphone or a tablet PC; a display device such as a liquid crystal display (LCD) or a plasma display (PDP) is representative. Stationary electronic equipment; and the like.
In the glass used for the above-mentioned electronic equipment, regardless of whether it is a mobile type or a stationary type, there is a high demand for weight reduction and space saving, and there is a tendency to reduce the plate thickness. . In particular, the edge of glass is susceptible to impacts and is likely to become a starting point of cracking, so there is a high demand for enhancing the edge strength.
That is, there is a demand for weight reduction and edge strength enhancement for glass for electronic devices used in electronic devices. However, the glass for electronic devices of the present invention has a relative thickness in the central region of the glass. Because it is light and thin, and the peripheral area is a thick part with a relatively thick plate, weight reduction and enhanced edge strength are achieved. It can be suitably used for the electronic device described above.

  Hereinafter, the electronic device glass of the present invention (hereinafter also simply referred to as “glass”) will be described in more detail with reference to FIGS. 1 to 5, but the present invention is not limited thereto. .

  FIG. 1 is a plan view schematically showing an example of the glass 1, and FIG. 2 is a side sectional view thereof.

As shown in FIG. 1, the region of the glass 1 is roughly divided into a central region 51 and a peripheral region 52 that is an outermost peripheral region surrounding the central region 51.
When the glass 1 is used as a cover glass, for example, the central region 51 mainly constitutes a region through which video / image is transmitted, but other regions may be constructed, and the peripheral region 52 is composed of video / image. You may comprise the area | region which permeate | transmits.

As shown in FIG. 2, the central region 51 is configured by the thin portion 11, and the peripheral region 52 is configured by the thick portion 12 that is thicker than the thin portion 11.
In addition, although the center area | region 51 is comprised only by the thin part 11, the peripheral area | region 52 may be partially comprised by the thin part 11, and may be comprised by the thick part 12 entirely. Good. That is, the thick portion 12 may be provided intermittently in a part of the peripheral region 52 or may be provided in the entire periphery of the glass 1 (the entire peripheral region 52).

As shown in FIG. 2, in the glass 1, the thick portion 12 that is relatively thicker than the thin portion 11 is disposed at the edge, and therefore, for example, the entire region including the peripheral region 52 is configured by the thin portion 11. Compared to the case, higher energy is required when breaking the edge. That is, the edge strength is excellent.
Moreover, in the glass 1, since the thin part 11 relatively thin rather than the thick part 12 comprises the center area | region 51 which occupies most of all the area | regions, when the whole area | region is comprised by the thick part 12, In comparison, the weight is reduced.
Thus, in the glass 1, weight reduction and edge strength enhancement are realized.

When the entire width of the glass 1 (distance in the left-right direction in FIG. 2) is “W1”, when the glass 1 is used in a portable device, W1 is used from the viewpoint of being used in a portable device that can be carried. It is preferably 300 mm or less, and more preferably 250 mm or less.
On the other hand, W1 is preferably 15 mm or more, and more preferably 20 mm or more, because a thick part having a sufficient thickness can be formed.

  In addition, when glass 1 is used for display apparatuses, such as LCD and PDP, it is preferable that W1 is 2500 mm or less, and it is more preferable that it is 2000 mm or less.

Moreover, when the thickness of the thin portion 11 (distance in the vertical direction in FIG. 2) is “T1”, when the glass 1 is used in a portable device, T1 is 1.1 mm from the viewpoint of weight reduction. The following is preferable, and 0.9 mm or less is more preferable.
On the other hand, T1 is preferably 0.2 mm or more and more preferably 0.4 mm or more because it has the minimum necessary strength.

  In addition, when glass 1 is used for display apparatuses, such as LCD and PDP, it is preferable that T1 is 1.1 mm or less, and it is more preferable that it is 0.9 mm or less.

  When the width of the thick portion 12 (distance in the left-right direction in FIG. 2) is “W2” and the thickness of the thick portion 12 (distance in the vertical direction in FIG. 2) is “T2”, these are described above. It can be defined by the ratio to “W1” or “T1”.

That is, the lower limit of the width (W2) of the thick portion 12 is expressed by T1 × X, and X is preferably 1.5 or more, and preferably 2 or more, because the edge strength is improved to a significant difference. More preferred.
On the other hand, since the increase in weight can be suppressed, the upper limit of W2 is represented by (W1 / 2) × Y, and Y is preferably 0.2 or less, and more preferably 0.1 or less.

Further, the thickness (T2) of the thick portion 12 is represented by T1 × Z, and Z is preferably 1.5 or more, and more preferably 2 or more, because the edge strength is improved to a significant degree. preferable.
On the other hand, when a force is applied to the thick portion 12, a bending stress is generated with the boundary between the thick portion 12 and the thin portion 11 as a fulcrum. When the thickness (T2) of the thick portion 12 is larger than the thickness (T1) of the thin portion 11, the bending stress generated when the same force is applied also increases. Z is preferably 65 or less, more preferably 30 or less, because the strength against bending stress is increased.

  In addition, in FIG. 2, although the thick part 12 showed the aspect protruded only to the upper surface side (upper side in FIG. 2) of the glass 1 with respect to the thin part 11, it is not limited to this, Next, as will be described with reference to FIG. 3, the thick portion 12 may also protrude to the lower surface side of the glass 1.

  FIG. 3 is a side sectional view schematically showing another example of the glass 1. In the glass 1 shown in FIG. 3, the thick portion 12 protrudes not only on the upper surface side (upper side in FIG. 3) of the glass 1 but also on the lower surface side (lower side in FIG. 3). ing. At this time, the thickness (T2) of the thick portion 12 is a thickness including portions protruding to the upper surface side and the lower surface side of the glass 1.

  The manufacturing method of the glass 1 is not specifically limited, For example, the method of grind | polishing one glass plate which has plate | board thickness more than the thickness (T2) of the thick part 12 and obtaining the glass 1 is mentioned. As the polishing method, a conventionally known method can be used, and examples thereof include a method of mechanically polishing the surface of the glass plate, a method of chemically polishing the surface of the glass plate, and the like.

  Moreover, the manufacturing method of the glass 1 is not limited to polishing, and for example, a method of obtaining a glass 1 by laminating a plurality of glass plates as described below with reference to FIG. .

FIG. 4 is a side sectional view schematically showing an example of the glass 1 constituted by a plurality of laminated glass plates. In the glass 1 shown in FIG. 4, a second glass plate 32 different from the first glass plate 31 is laminated on the peripheral region 52 of the first glass plate 31. The first glass plate 31 constitutes the thin part 11 and a part of the thick part 12, and the second glass plate 32 constitutes the remaining part of the thick part 12.
In addition, the 1st glass plate 31 and / or the 2nd glass plate 32 may be further comprised by the laminated | stacked several glass plate.

  The method for laminating is not particularly limited, and a conventionally known method can be used. For example, a method of bonding the first glass plate 31 and the second glass plate 32 to each other by bonding; A method of heating the plate 31 and the second glass plate 32 to a temperature equal to or higher than the softening point of the two and fusing them together.

The glass composition of the glass 1 demonstrated based on FIGS. 1-4 is not specifically limited. Moreover, when the glass 1 is comprised with several glass plates (refer FIG. 4), the glass composition of several glass plates may be the same, or may mutually differ.
However, the glass 1 may be subjected to a chemical strengthening treatment as described below with reference to FIG. 5, and in that case, as the glass 1, it is necessary to select a glass containing an alkali component, Alkali aluminosilicate glass is preferred.

  FIG. 5 is a side sectional view schematically showing an example of the glass 1 subjected to the chemical strengthening treatment. On the surface of the glass 1 shown in FIG. 5, a chemical strengthening layer 41 that has been subjected to a chemical strengthening process, which will be described later, and has generated a compressive stress (hereinafter also referred to as “chemically strengthened compressive stress”) is formed.

  The depth of the chemical strengthening layer 41 is not particularly limited, and is preferably 15 to 50 μm, for example. Moreover, the chemical strengthening compressive stress of the chemical strengthening layer 41 is not particularly limited, and is preferably 600 to 2000 MPa, for example.

The chemical strengthening treatment generally includes an alkali component (for example, an alkali metal ion such as Li ion or Na ion, hereinafter also referred to as “small-diameter alkali component”) present in the glass plate, and an alkali having a larger ion radius. This is a so-called ion exchange treatment in which a component (for example, an alkali metal ion such as K ion or the like, hereinafter also referred to as “large-diameter alkali component”) is substituted.
Therefore, the concentration of the large-diameter alkaline component in the chemically strengthened layer 41 is higher than that in the portion excluding the chemically strengthened layer 41. That is, the chemical strengthening layer 41 and the portion excluding the chemical strengthening layer 41 can be clearly distinguished by the difference in the concentration of the large-diameter alkaline component.

Specific examples of the chemical strengthening treatment include a method of immersing the glass 1 in a potassium nitrate (KNO ₃ ) molten salt for 0.25 to 5 hours. The chemical strengthening treatment may include a preheat treatment for preheating using a heater or the like as a pretreatment for immersion. Examples of the temperature of the chemical strengthening treatment (including preheat treatment) include 550 ° C. or lower.

Note that the chemically strengthened layer 41 may be formed on the laminated glass 1 (see FIG. 4). At this time, when laminating by bonding at a temperature of 100 ° C. or lower, the timing of performing the chemical strengthening treatment may be before or after the lamination. That is, in the case of the glass 1 shown in FIG. 4, you may laminate | stack, after giving the chemical strengthening process to the 1st glass plate 31 and / or the 2nd glass plate 32. FIG.
However, when laminating by heat fusion, the effect of the chemical strengthening treatment disappears due to heating at the time of fusion, so that it is necessary to perform the chemical strengthening treatment after the lamination.

Here, not only when a part of the glass 1 (for example, the second glass plate 32 shown in FIG. 4) is subjected to the chemical strengthening treatment, but as shown in FIG. Consider the case where 41 is formed.
In this case, compressive stress acts on the end surface 12a on the central region 51 side in the thick portion 12 and the surface 11a of the thin portion 11 connected to the end surface 12a. The intersection P1 where the end surface 12a and the surface 11a intersect is pulled by the compressive stress acting on the end surface 12a and the surface 11a. For this reason, the tearing force works at the intersection P1, and cracking is likely to occur. Further, heat is likely to accumulate at the intersection P1 during the chemical strengthening process.

At this time, in the cross-sectional view as shown in FIG. 5, the tearing force acting on the intersection P1 becomes less concentrated as the angle formed by the end surface 12a and the surface 11a (hereinafter also referred to as “angle θ”) is obtuse. Cracks at the intersection P1 can be suppressed. In addition, heat does not collect easily.
From such a viewpoint, when the chemical strengthening layer 41 is formed, the angle θ is preferably 90 degrees or more and less than 180 degrees, and more preferably 135 degrees or more and less than 180 degrees.

  As shown in FIG. 5, when the angle θ is other than 90 degrees, the end surface 12 a of the thick portion 12 is inclined, so that the width (W2) of the thick portion 12 is in the thickness direction of the thick portion 12. In this case, the width (W2) of the thick portion 12 is the maximum width, although it depends on the position.

Further, the shape of the glass 1 is not limited to the above-described shape. For example, as described below with reference to FIG. 6, the end surface 12a of the thick portion 12 and the surface 11a of the thin portion 11 are smoothly connected. It may be.
FIG. 6 is a side sectional view showing an example of the glass 1 whose end surface 12a is curved in a concave shape in a sectional view and connected to the surface 11a. In the glass 1 shown in FIG. 6, only the end face 12a is curved in a sectional view shape, and the surface 11a is a flat face.
Also in the glass 1 shown in FIG. 6, when the angle θ formed by the end face 12 a and the surface 11 a is an obtuse angle, the chemical strengthening layer 41 (not shown in FIG. 6) is formed on the entire surface of the glass 1. Even if it exists, the crack in the intersection P1 can be suppressed and heat is hard to collect.
In the glass 1 shown in FIG. 6, as in the case described with reference to FIG. 5, the width (W2) of the thick portion 12 varies depending on the position of the thick portion 12 in the thickness direction. The maximum width.

  As described above, the glass for electronic devices according to the present invention is suitably used as a cover glass or a glass substrate mounted on a portable device or a display device because it achieves weight reduction and enhanced edge strength.

  Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to these.

<Glass composition>
Details of the glass layer used in the following examples and the like are as follows.

(Glass A)
- _Composition: SiO 2 64.3 mole%, _Al 2 _{O 3} 6 mol%, MgO 11 mol%, CaO 0.1 mol%, SrO 0.06 mol%, BaO 0.04 mol%, _Na 2 O 12 moles %, K ₂ O 4 mol%, ZrO ₂ 2.5 mol%
Thermal expansion coefficient: 91 × 10 ⁻⁷ / K
Glass transition temperature: 620 ° C
Softening point: 842 ° C
-Refractive index: 1.52
・ Young's modulus: 78GPa
-Poisson's ratio: 0.22

<Example 1>
Using the glass A, a glass 1 having a sectional view shown in FIG. 2 was produced. At this time, the total width (W1) of the glass 1, the width (W2) of the thick portion 12, the thickness (T1) of the thin portion 11, the thickness (T2) of the thick portion 12, and the angle θ are as follows. As shown in Table 1.
Specifically, the surface of glass A having a total width and thickness larger than W1 and T2, respectively, is polished using cerium oxide, and the end surface is ground using diamond abrasive grains having a grain size of # 600. After the processing, the central region 51 is ground using a # 600 diamond abrasive grain so as to form a counterbore in a square shape, thereby producing the glass 1 having a cross-sectional view shown in FIG.

<Comparative Examples 1 and 2>
Glass A for electronic equipment was produced by polishing glass A having the same size as that used in Example 1, but unlike Example 1, the thickness was made uniform without providing thick portion 12. . The thickness at this time is referred to as “T1” for convenience and is shown in Table 1 below. Further, since the thick part 12 was not provided, “−” was described in Table 1 below for the width (W2) and thickness (T2) of the thick part 12 and the angle θ.

<Evaluation>
(Edge strength)
A 307 g cylinder (diameter: 40 mm) was struck from the horizontal lateral direction against the edge of the glass tilted 10 degrees from the vertical direction to the surface in contact with the loader, and the edge was broken. The cylinder draws a pendulum-like orbit and comes into contact with the glass, and the impact energy applied to the glass can be varied according to its initial height.
The test was repeated for 20 glasses, and when the average value of the impact energy when broken was 0.02 J or more, it was evaluated as “A”, and when it was less than 0.02 J Rated "B".
From the viewpoint of practicality, “A” can be evaluated as having excellent edge strength.

(Lightweight)
The mass of the glass of Example 1 was set as a reference “B”, and when it was lighter than Example 1, it was evaluated as “A”, and when it was heavier than Example 1, it was evaluated as “C”.
If it is "A" or "B", it can be evaluated as being excellent in lightness.

As is clear from the results shown in Table 1, the edge strength was “A” and the lightness was “B” in Example 1, so both edge strength enhancement and weight reduction were realized. I understood that I was able to do it.
On the other hand, it was found that Comparative Example 1 was inferior in edge strength while having good lightness, and Comparative Example 2 was inferior in lightness in spite of good edge strength.

<Example 2>
Glass 1 was produced in the same manner as in Example 1, but at this time, W1 was 600 mm, W2 was 5 mm, T1 was 1.1 mm, and T2 was 3.0 mm.

<Example 3>
Using the glass A, a glass 1 having a sectional view shown in FIG. 4 was produced. At this time, W1, W2, T1, T2, and the angle θ were the same as in Example 1. More specifically, the second glass plate 32 using the glass A is heated to a temperature equal to or higher than the softening point of the glass A in the peripheral region 52 of the first glass plate 31 using the glass A. The end faces were ground using diamond abrasive grains having a grain size of # 600.

<Example 4>
First, glass was produced in the same manner as in Example 1, but at this time, the angle θ was 90 degrees. Next, the prefabricated glass was preheated using a heater, then immersed in KNO ₃ molten salt (immersion time: 1 hour, immersion temperature: 435 ° C.), dried after washing with pure water, and shown in FIG. A glass 1 having a chemically strengthened layer 41 having a cross-sectional view was obtained. The preheating temperature was the same as the immersion temperature.

1 Glass (glass for electronic equipment)
DESCRIPTION OF SYMBOLS 11 Thin part 12 Thick part 31 1st glass plate 32 2nd glass plate 41 Chemical strengthening layer 51 Central area | region 52 Peripheral area | region P1 Intersection T1 Thin part thickness T2 Thick part thickness W1 Full width W2 of glass Meat width θ angle

Claims (6)

Electronic glass,
A thin portion constituting the central region of the glass;
An electronic device glass comprising a peripheral portion surrounding the central region and a thick portion thicker than the thin portion.   The glass for electronic devices according to claim 1, wherein the thick portion is configured by laminating a plurality of glass plates.   The glass for electronic devices according to claim 2, wherein the plurality of glass plates have different glass compositions.   The glass for electronic devices of any one of Claims 1-3 which has the chemical strengthening layer which generated the compressive stress by the chemical strengthening process on the surface.   5. The electronic device according to claim 4, wherein an angle formed by an end surface on the central region side in the thick portion and a surface of the thin portion connected to the end surface is 90 degrees or more and less than 180 degrees in a cross-sectional view. Glass.   The glass for electronic devices according to any one of claims 1 to 5, wherein an end surface on the central region side of the thick portion is curved in a concave shape in a cross-sectional view and connected to the surface of the thin portion. .