Chemically strengthened glass and method for producing same

Abstract

Provided are: a chemically strengthened glass having a sheet thickness of greater than 2 mm, a surface compressive stress CS0 of 400-1200 MPa, a compressive stress layer depth DOL-tail of 2.7-30.0 [mu] m, an absolute value of an average slope of a stress curve from the surface to the DOL-tail of 20-500 MPa / [mu] m, a tensile stress CT of 1.0-16 MPa, and a thickness of 0.5-10 [mu] m; the method for producing chemically strengthened glass comprises a step of bringing glass for chemical strengthening having a sheet thickness of greater than 2 mm into contact with an inorganic salt composition containing 80 mass% or more of potassium nitrate to perform ion exchange.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing chemically strengthened glass and chemically strengthened glass. In particular, it relates to chemically strengthened glass suitable as glass for protecting sensor modules and sensors or oscillators, and a method for manufacturing the same. Background Art

[0002] Mobile devices such as automobiles, trains, and drones, as well as safety devices such as outdoor sensors and surveillance cameras, are equipped with multiple sensors having various functions. Sometimes, the use of sensors is hindered by the structure and materials of the protective components, so the types of sensors arranged inside the protective components also become factors in selecting the structure and materials of the protective components.

[0003] As a material for a protective component that protects a sensor, it is desirable to select a material having high transmittance of visible light and excellent strength. There are known sensor modules that use glass as a protective component for protecting sensors. For example, a sensor module that uses chemically strengthened glass as a protective component is disclosed in Patent Document 1.

[0004] In recent years, due to the increasing requirements for energy conservation, the number of cases where solar cell arrays are installed on the outer side of buildings (for example, on houses or roofs) has increased. A solar cell array is constituted by arranging a plurality of panel-shaped solar cell modules in a plane and connecting them in series and in parallel. A protective component is adopted on the solar cell module installed on the outer side of a building to protect it from the effects of weather such as hail and snow, falling objects, etc. A solar cell module having glass as a protective component for the solar cell module is disclosed in Patent Document 2.

[0005] Chemically strengthened glass is glass in which a compressive stress layer is formed in a surface portion of the glass by an ion exchange treatment in which the glass is brought into contact with an inorganic salt composition such as sodium nitrate or potassium nitrate. In this ion exchange treatment, ion exchange occurs between the alkali metal ions contained in the glass and the alkali metal ions having a larger ionic radius contained in the inorganic salt composition, and a compressive stress layer is formed in the surface portion of the glass. The strength of chemically strengthened glass depends on a stress curve represented by compressive stress (hereinafter, also abbreviated as CS) that varies with the depth from the glass surface.

[0006] Prior Art Documents

[0007] Patent Documents

[0008] Patent Document 1: WO 2019 / 009336

[0009] Patent Document 2: JP 2007 - 123725 A Summary of the Invention

[0010] The strength expected for glass used as a protective component for sensors and solar cell modules can be roughly divided into three types. The first is resistance to flying stones. For example, when a sensor is mounted on a mobile device, there is a situation where foreign objects such as flying stones during movement collide with the sensor module. In this way, when an instantaneous impact is applied from the outside due to the collision of flying stones or the like, it is possible that the stress at the time of collision is not relieved and concentrated stress is generated, resulting in breakage of the glass and the sensor as the protective component. Therefore, glass for protecting sensors is required to have excellent resistance to flying stones. The second is the ball-drop impact strength (hereinafter, also abbreviated as ball-drop strength). It is necessary to have a strength that does not break easily when an object collides with the glass as the protective component or when the glass is dropped. Thirdly, since scratches generated on the glass surface due to the collision of flying stones or the like, and breakage and deterioration of the appearance caused by these scratches become problems, it is necessary to reduce the area and depth of these scratches, that is, the scratch resistance to flying stones (hereinafter, also abbreviated as scratch resistance).

[0011] Therefore, an object of the present invention is to provide a chemically strengthened glass and a method for manufacturing the same, which exhibit excellent resistance to flying stones, ball-drop strength, and scratch resistance as compared with the prior art.

[0012] The inventors of the present invention conducted research on the above problems, and as a result, found that by subjecting a chemically strengthened glass having a plate thickness greater than 2 mm to ion exchange using a molten salt composition mainly composed of potassium nitrate, a chemically strengthened glass having a specific stress curve can be obtained, and the resistance to flying stones, ball-drop strength, and scratch resistance can be improved by this chemically strengthened glass, thereby completing the present invention.

[0013] The present invention is as follows.

[0014] 1. A chemically strengthened glass having a plate thickness greater than 2 mm, a surface compressive stress CS0 of 400 to 1200 MPa, a depth of the compressive stress layer DOL-tail of 2.7 to 30.0 μm, an absolute value of the average slope of the stress curve from the surface to DOL-tail of 20 to 500 MPa / μm, and a tensile stress CT of 1.0 to 16 MPa.

[0015] 2. The chemically strengthened glass according to 1 above, wherein the absolute value of the average slope of the stress curve from a position 50 μm from the surface to DOC is 0.00 to 0.90 MPa / μm.

[0016] 3. The chemically strengthened glass according to 1 or 2 above, wherein, expressed as a molar percentage on an oxide basis, the difference between the average Na concentration at a depth of 25 to 30 μm from the surface and the Na concentration at the center of the plate thickness is 1% or less.

[0017] 4. The chemically strengthened glass according to any one of 1 to 3 above, wherein the integrated value (MPa·μm) of the tensile stress is 20,000 or less.

[0018] 5. The chemically strengthened glass according to any one of 1 to 4 above, which is a lithium-containing aluminosilicate glass.

[0019] 6. The chemically strengthened glass according to any one of 1 to 5 above, wherein the absolute value of the difference between the maximum crack arrest line depth and the minimum crack arrest line depth is 650 μm or more.

[0020] 7. The chemically strengthened glass according to any one of 1 to 6 above, wherein the absolute value of the difference between the maximum crack arrest line depth and the maximum crack depth is 40 μm or more.

[0021] 8. The chemically strengthened glass according to any one of 1 to 7 above, wherein the fracture generation rate evaluated according to the strength test method of Test Method B of ISO20567-1 is 20% or less.

[0022] 9. The chemically strengthened glass according to any one of 1 to 8 above, wherein the ball drop strength measured with a 500 g iron ball is 64 cm or more.

[0023] 10. The chemically strengthened glass according to any one of 1 to 9 above, wherein the plate thickness is 10 mm or less.

[0024] 11. The chemically strengthened glass according to any one of 1 to 10 above, wherein the surface roughness (Ra) is 0.20 nm or more,

[0025] the hydrogen concentration Y in the region at a depth of X from the outermost surface of the glass satisfies the following relational expression (I) when X = 0.1 to 0.4 (μm), and the surface has no grinding marks.

[0026] Y = aX + b (I)

[0027] 〔The meanings of the symbols in formula (I) are as follows.

[0028] Y: hydrogen concentration (in terms of H2O, mol / L)

[0029] X: depth from the outermost surface of the glass (μm)

[0030] a: -0.150 to 0.010

[0031] b: 0.000 to 0.220〕

[0032] 12. The chemically strengthened glass according to any one of 1 to 11 above, which is for vehicle-mounted sensors.

[0033] 13. A method for manufacturing chemically strengthened glass, comprising the following steps: bringing chemically strengthening glass with a plate thickness greater than 2 mm into contact with an inorganic salt composition containing 80% by mass or more of potassium nitrate for ion exchange.

[0034] 14. The method for manufacturing chemically strengthened glass according to item 13 above, wherein the ion exchange is to bring the chemically strengthening glass into contact with an inorganic salt composition containing 80% by mass or more of potassium nitrate and containing at least one salt selected from K2CO3, Na2CO3, KHCO3, NaHCO3, K3PO4, Na3PO4, K2SO4, Na2SO4, KOH, and NaOH to obtain chemically strengthened glass, and further comprising the following steps:

[0035] After the ion exchange, cleaning the chemically strengthened glass,

[0036] After the cleaning, performing acid treatment on the chemically strengthened glass,

[0037] After the acid treatment, performing alkali treatment on the chemically strengthened glass.

[0038] 15. The method for manufacturing chemically strengthened glass according to item 13 or 14 above, wherein the surface compressive stress CS0 of the chemically strengthened glass is 400 - 1200 MPa, the depth of the compressive stress layer DOL - tail is 2.7 - 30.0 μm, the absolute value of the average slope of the stress curve from the surface to DOL - tail is 20 - 500 MPa / μm, and the tensile stress CT is 1.0 - 16 MPa.

[0039] 16. The method for manufacturing chemically strengthened glass according to any one of items 13 - 15 above, wherein the chemically strengthening glass is a lithium-containing aluminosilicate glass.

[0040] 17. The chemically strengthened glass according to any one of items 1 - 12 above, wherein the plate thickness is greater than 2 mm and 10 mm or less, and when the plate thickness is set as T, the depth of the compressive stress layer DOL - tail is 0.03T or less.

[0041] 18. The chemically strengthened glass according to any one of items 1 - 12 and 17 above, wherein the plate thickness is greater than 2 mm and 10 mm or less, and DOL - tail is 10 μm or less.

[0042] 19. The chemically strengthened glass according to any one of items 1 - 12, 17, and 18 above, wherein the tensile stress CT is 1.0 - 4.0 MPa.

[0043] 20. The chemically strengthened glass according to any one of the above items 1 to 12 and 17 to 19, wherein the absolute value of the average slope of the stress curve from the surface to the DOL - tail is 50 to 200 MPa / μm.

[0044] 21. The chemically strengthened glass according to any one of the above items 1 to 12 and 17 to 20, wherein the collision energy measured by the falling ball test based on a 500 g iron ball is 3 J or more.

[0045] 22. The chemically strengthened glass according to any one of the above items 1 to 12 and 17 to 21, which does not break even when a hockey puck with a diameter of 55 mm collides at a speed of 33.9 m / s in the hockey puck test.

[0046] Among them, the above hockey puck test is carried out according to the following method.

[0047] Method: Make the hockey puck collide with a 100 mm × 100 mm glass.

[0048] 23. The chemically strengthened glass according to any one of the above items 1 to 12 and 17 to 22, wherein the Martens hardness MH when evaluated using PICODENTOR (registered trademark) of HM500 is 3600 N / mm 2 or more.

[0049] 24. A solar power generation module, in which a light - receiving panel and a solar cell substrate are sequentially laminated from the light - receiving surface side toward the back surface side,

[0050] the above light - receiving panel is the chemically strengthened glass according to any one of the above items 1 to 12 and 17 to 23,

[0051] the Sa of the light - receiving surface of the above light - receiving panel is 10 nm or less and the 20° glossiness is 100% or more.

[0052] 25. A solar power generation module, in which a light - receiving panel and a solar cell substrate are sequentially laminated from the light - receiving surface side toward the back surface side,

[0053] the above light - receiving panel is the chemically strengthened glass according to any one of the above items 1 to 12 and 17 to 23,

[0054] the Sn content in the range from the surface to a depth of 5 μm on the light - receiving surface of the above light - receiving panel is 10 times or more the Sn content in the range from the surface to a depth of 5 μm on the surface of the above light - receiving panel opposite to the light - receiving surface.

[0055] 26. A solar power generation module, in which a light - receiving panel and a solar cell substrate are sequentially laminated from the light - receiving surface side toward the back surface side,

[0056] The light-receiving panel is the chemically strengthened glass according to any one of the above items 1 to 12 and 17 to 23.

[0057] The absolute value of the difference between the CS0 of the light-receiving surface of the light-receiving panel and the CS0 of the surface of the light-receiving panel opposite to the light-receiving surface is 10 MPa or more.

[0058] 27. A solar power generation module includes a light-receiving panel, a solar cell substrate, and a back panel laminated in this order from the light-receiving surface side toward the back surface side.

[0059] The light-receiving panel is the chemically strengthened glass according to any one of the above items 1 to 12 and 17 to 23.

[0060] The back panel is a glass having a thickness 1 mm or more thinner than that of the light-receiving panel.

[0061] 28. The chemically strengthened glass according to any one of the above items 1 to 12 and 17 to 23, which has a first main surface, a second main surface opposite to the first main surface, and an end portion.

[0062] In either the first main surface or the second main surface, the shape of one of the four corners is different or the shapes of the four corners are different from each other.

[0063] The end portion is chamfered with a C-chamfer or an R-chamfer.

[0064] 29. A building includes the chemically strengthened glass according to any one of the above items 1 to 12 and 17 to 23 as an outer surface member.

[0065] Due to having a plate thickness and a stress curve within a specific range, particularly CT within a specific range, the chemically strengthened glass of the present invention exhibits excellent anti-flyrock property, ball-drop strength, and scratch resistance. According to the manufacturing method of the chemically strengthened glass of the present invention, by subjecting a chemically strengthened glass with a plate thickness greater than 2 mm to ion exchange under specific conditions, a chemically strengthened glass with CT within a specific range and excellent anti-flyrock property, ball-drop strength, and scratch resistance can be manufactured. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Figure 1 In (a) and (b) of, a perspective view showing a configuration example of a protective member formed of a part or all of the chemically strengthened glass of the present embodiment.

[0067] Figure 2 A graph showing the correlation between the tensile stress CT and the anti-flyrock property.

[0068] Figure 3 In (a) to (f) of, a graph showing an example of the stress curve of the chemically strengthened glass of the present embodiment. Figure 3Among them, (a) and (d) represent the measurement results based on the FSM, Figure 3 and (b), (c), (e) and (f) among them represent the measurement results based on the SLP.

[0069] Figure 4 It is a figure showing the result of observing the sample after the flying stone test using a microscope.

[0070] Figure 5 It is a figure showing the crack arrest lines generated on the fracture surface of the sample after the flying stone test. Detailed implementation mode

[0071] Hereinafter, the present invention will be described in detail. However, the present invention is not limited to the following embodiments, and can be implemented with any deformation without departing from the gist of the present invention.

[0072] In this specification, "~" indicating a numerical range is used to mean including the numerical values described before and after it as the lower limit value and the upper limit value. In addition, in this specification, the composition of the glass (content of each component) is described in terms of mol% on an oxide basis, unless otherwise specified.

[0073] Hereinafter, "chemically strengthened glass" refers to glass after chemical strengthening treatment, and "glass for chemical strengthening" refers to glass before chemical strengthening treatment.

[0074] In this specification, unless otherwise specified, the glass composition is expressed in mol% on an oxide basis, and mol% is abbreviated as "%". In addition, "substantially does not contain" in this specification means below the impurity level contained in raw materials, etc., that is, not intentionally added. Specifically, for example, less than 0.1%.

[0075] In this specification, the "stress curve" refers to a curve representing the compressive stress value with the depth from the glass surface as a variable. In the stress curve, the tensile stress is expressed as a negative compressive stress.

[0076] "Compressive stress (CS)" can be measured by thinning the cross-section of the glass and analyzing the thinned sample using a birefringence imaging system. The birefringence imaging system birefringence stress meter is a device that uses a polarizing microscope and a liquid crystal compensator, etc. to measure the magnitude of the retardation generated by stress. For example, there is the birefringence imaging system Abrio-IM manufactured by CRi Corporation.

[0077] In addition, sometimes it can also be measured using scattered light photoelasticity. In this method, light can be incident from the surface of the glass, and the polarized light of the scattered light can be analyzed to measure CS. As a stress measuring device using scattered light photoelasticity, for example, there is the scattered light photoelastic stress meter SLP-2000 manufactured by Oriehara Seisakusho.

[0078] In this specification, the "depth of compressive stress layer (DOC)" is the depth at which the compressive stress value is zero. Hereinafter, the surface compressive stress value may sometimes be denoted as CS0. In addition, the "internal tensile stress (CT)" refers to the tensile stress value at a depth of 1 / 2 of the plate thickness t.

[0079] In this specification, the fracture generation rate is evaluated according to the strength test method of ISO20567-1 Test Method B under the following conditions.

[0080] (Condition)

[0081] Projectiles: Chilled Iron Grit

[0082] Stone size: 3.55 - 5 mm

[0083] Shot volume: 500 g

[0084] Shot pressure: 200 kPa

[0085] Sample setting angle: 54°

[0086] Shot time: 8 - 12 s

[0087] Shot times: 2

[0088] Sample collision area: 40×40 mm

[0089] <Stress measurement method>

[0090] In recent years, in the application of cover glass for smartphones and the like, glass that has undergone two-step chemical strengthening has become the mainstream. The two-step chemical strengthening is to exchange lithium ions and sodium ions inside the glass (Li-Na exchange), and then further exchange sodium ions inside the glass with potassium ions in the surface layer of the glass (Na-K exchange).

[0091] In order to obtain the stress curve of such two-step chemically strengthened glass in a non-destructive manner, for example, a Scattered Light Photoelastic Stress Meter (hereinafter also abbreviated as SLP), a Film Stress Measurement (hereinafter also abbreviated as FSM), etc. can be used in combination.

[0092] In the method using a scattered light photoelastic stress meter (SLP), compressive stress from Li-Na exchange can be measured inside the glass at a distance of several tens of μm or more from the glass surface layer. On the other hand, in the method using a glass surface stress meter (FSM), compressive stress from Na-K exchange can be measured in the glass surface layer portion at a distance of several tens of μm or less from the glass surface (for example, International Publication No. 2018 / 056121, International Publication No. 2017 / 115811). Therefore, as the stress curves of the glass surface layer and the interior in the two-step chemically strengthened glass, stress curves obtained by synthesizing the information of SLP and FSM are sometimes used.

[0093] In the present invention, a stress curve measured using a scattered light photoelastic stress meter (SLP) is mainly used. It should be noted that when referring to the compressive stress CS2, tensile stress CT, depth of compressive stress layer DOC, etc. in this specification, it refers to the values in the SLP stress curve.

[0094] A scattered light photoelastic stress meter is a stress measurement device that has: a polarization light phase difference variable member that changes the polarization light phase difference of a laser by more than one wavelength with respect to the wavelength of the laser, an imaging element that captures multiple images by repeatedly photographing the scattered light generated by irradiating the strengthened glass with the laser whose polarization light phase difference has been changed at a predetermined time interval, and an arithmetic unit that measures the periodic brightness change of the scattered light using the multiple images, calculates the phase change of the brightness change, and calculates the stress distribution in the depth direction from the surface of the strengthened glass based on the phase change.

[0095] As a method for measuring a stress curve using a scattered light photoelastic stress meter, the method described in International Publication No. 2018 / 056121 can be cited. As a scattered light photoelastic stress meter, for example, SLP-1000 and SLP-2000 manufactured by Oriehara Seisakusho can be cited. If the attached software SlpIV_up3 (Ver. 2019.01.10.001) is combined with these scattered light photoelastic stress meters, high-precision stress measurement can be performed.

[0096] In this specification, the average slope of the stress curve means that in a stress curve with the depth from the glass surface on the horizontal axis and the compressive stress on the vertical axis, the slope of the stress curve is calculated for each 1 μm within the depth range where the slope is obtained, and the average value is obtained from the obtained slopes.

[0097] <<Chemically Strengthened Glass>>

[0098] <<<Stress Curve>>>

[0099] The chemically strengthened glass of this embodiment (hereinafter, also simply referred to as this chemically strengthened glass) is characterized in that: the plate thickness is greater than 2 mm, the surface compressive stress CS0 is 400 to 1200 MPa, the depth of the compressive stress layer DOL-tail is 2.7 to 30.0 μm, the absolute value of the average slope of the stress curve from the surface to DOL-tail is 20 to 500 MPa / μm, and the tensile stress CT is 1.0 to 16 MPa. It should be noted that in this specification, DOL-tail refers to the depth of the compressive stress layer (μm) measured by FSM. In addition, "to DOL-tail", "to DOC", and "to the center of the plate thickness" mean including DOL-tail, DOC, and the center of the plate thickness, respectively.

[0100] The plate thickness of this chemically strengthened glass is greater than 2 mm, preferably 2.5 mm or more, more preferably 3 mm or more, further preferably 4 mm or more, and particularly preferably 5 mm or more. By having a plate thickness greater than 2 mm, the strength is improved, and excellent anti-flyrock property is exhibited. In addition, from the viewpoint of achieving weight reduction, the plate thickness is preferably 10 mm or less, 9 mm or less, 8 mm or less, 7 mm or less, more preferably 6.6 mm or less, further preferably 6.2 mm or less, and particularly preferably 5.8 mm or less in the following order.

[0101] From the viewpoint of improving the bending strength, the surface compressive stress CS0 of this chemically strengthened glass is preferably 400 MPa or more, more preferably 500 MPa or more, further preferably 550 MPa or more, and particularly preferably 600 MPa or more. In addition, from the viewpoint of achieving the balance between the compressive stress and the tensile stress, the surface compressive stress CS0 is preferably 1200 MPa or less, more preferably 1150 MPa or less, and further preferably 1100 MPa or less.

[0102] The depth of the compressive stress layer DOL-tail of this chemically strengthened glass is 2.7 μm or more, preferably 3.0 μm or more, more preferably 4.5 μm or more, and particularly preferably 6.0 μm or more. DOL-tail is 30.0 μm or less, preferably 25.0 μm or less, more preferably 20.0 μm or less, further preferably 15.0 μm or less, particularly preferably 10.0 μm or less, and most preferably 6.0 μm or less. By making DOL-tail 2.7 μm to 30.0 μm, excellent anti-flyrock property, ball-drop strength, and scratch resistance are exhibited.

[0103] From the viewpoint of further improving the ball-drop strength, the plate thickness T of this chemically strengthened glass is greater than 2 mm and 10 mm or less, and when the plate thickness is T, the depth of the compressive stress layer DOL-tail is preferably 0.03T or less, more preferably 0.02T or less, further preferably 0.01T or less, and particularly preferably 0.005T or less.

[0104] The absolute value of the average slope of the stress curve from the surface to DOL-tail of this chemically strengthened glass (hereinafter, also abbreviated as the surface layer slope) is 20 MPa / μm or more, preferably 30 MPa / μm or more, more preferably 40 MPa / μm or more, further preferably 50 MPa / μm or more, and particularly preferably 100 MPa / μm or more. The absolute value of this average slope is 500 MPa / μm or less, preferably 400 MPa / μm or less, more preferably 350 MPa / μm or less, further preferably 300 MPa / μm or less, particularly preferably 250 MPa / μm or less, and most preferably 200 MPa / μm or less. By making the absolute value of this surface layer slope 20 MPa / μm to 500 MPa / μm, excellent anti-spalling property, ball-drop strength, and scratch resistance are exhibited. In addition, by making the absolute value of this surface layer slope 50 MPa / μm to 200 MPa / μm, more excellent ball-drop strength is shown.

[0105] The tensile stress CT of this chemically strengthened glass is 1.0 MPa or more, preferably 1.5 MPa or more, more preferably 2.0 MPa or more, and further preferably 2.5 MPa or more. The tensile stress CT is 16 MPa or less, preferably 13 MPa or less, more preferably 10 MPa or less, further preferably 5.0 MPa or less, and particularly preferably 4.0 MPa or less. As Figure 2 shown, when the plate thickness is greater than 2 mm, there is a correlation between CT and anti-spalling property. By making the tensile stress 1.0 MPa to 16 MPa, excellent anti-spalling property, ball-drop strength, and scratch resistance are shown. In addition, by making the tensile stress 1.0 MPa to 4.0 MPa, more excellent ball-drop strength is shown.

[0106] The absolute value of the average slope of the stress curve from a position 50 μm from the surface to the DOC of this chemically strengthened glass (hereinafter, also abbreviated as the deep slope) is preferably 0.00 MPa / μm or more, more preferably 0.02 MPa / μm or more, still more preferably 0.04 MPa / μm or more, and particularly preferably 0.06 MPa / μm or more. The absolute value of this average slope is preferably 0.90 MPa / μm or less, more preferably 0.80 MPa / μm or less, still more preferably 0.70 MPa / μm or less, and particularly preferably 0.60 MPa / μm or less. By making the absolute value of this deep slope 0.00 MPa / μm to 0.90 MPa / μm, the resistance to spalling, the ball drop strength, and the scratch resistance can be further improved.

[0107] The absolute value of the average slope of the stress curve from a depth of 400 μm from the surface to the center of the plate thickness of this chemically strengthened glass is preferably 0.010 MPa / μm or less, more preferably 0.008 MPa / μm or less, still more preferably 0.006 MPa / μm or less, and particularly preferably 0.005 MPa / μm or less. The lower limit of the absolute value of this average slope is not particularly limited, and is preferably 0.000 MPa / μm or more. By making the average slope from a depth of 400 μm to the center of the plate thickness 0.000 MPa / μm to 0.010 MPa / μm, the resistance to spalling, the ball drop strength, and the scratch resistance can be further improved.

[0108] In terms of the molar percentage based on oxides of this chemically strengthened glass, the difference between the average Na concentration at a depth of 25 to 30 μm from the surface and the Na concentration at the center of the plate thickness is preferably 1% or less. This difference is more preferably 0.9% or less, still more preferably 0.8% or less, and particularly preferably 0.7% or less. The lower limit of this difference is not particularly limited, and is preferably 0.02% or more, for example. By making this difference 1.0% or less, the resistance to spalling, the ball drop strength, and the scratch resistance can be further improved. The Na concentration can be measured by a known method using EPMA.

[0109] The integrated value ICT (MPa·μm) of the tensile stress of this chemically strengthened glass is preferably 20000 or less, more preferably 18000 or less, still more preferably, and particularly preferably 16000 or less. By making the integrated value ICT (MPa·μm) of the tensile stress 20000 or less, the energy contributing to crack development can be suppressed, and thus the resistance to spalling, the ball drop strength, and the scratch resistance can be further improved. From the viewpoint of improving strength, the integrated value ICT (MPa·μm) of the tensile stress is preferably 500 or more, more preferably 1000 or more, still more preferably 2000 or more, and particularly preferably 3000 or more. The integrated value ICT of the tensile stress refers to the integrated value of the tensile stress in a region deeper than the DOC.

[0110] This chemically strengthened glass preferably has a first main surface, a second main surface opposite to the first main surface, and an end portion. In either the first main surface or the second main surface, the shape of one of the four corners is different or the shapes of the four corners are different from each other, and the end portion is chamfered with a C-chamfer or an R-chamfer. By having the above shape, when used as a component such as a solar power generation module, advantages such as being easy to identify the light-receiving surface can be obtained, and the production efficiency can be improved.

[0111] (Hydrogen concentration and surface roughness)

[0112] This chemically strengthened glass preferably has a surface roughness (Ra) of 0.20 nm or more, and the hydrogen concentration Y in the region of the depth X from the outermost surface of the glass satisfies the following relational expression (I) when X = 0.1 to 0.4 (μm), and there are no grinding marks on the surface.

[0113] Y = aX + b (I)

[0114] 〔The meanings of the symbols in formula (I) are as described below.

[0115] Y: Hydrogen concentration (H2O conversion, mol / L)

[0116] X: Depth from the outermost surface of the glass (μm)

[0117] a: -0.150 to 0.010

[0118] b: 0.000 to 0.220〕

[0119] If the hydrogen concentration in the glass is high, hydrogen enters the Si - O - Si bonding network of the glass in the form of Si - OH, and the Si - O - Si bond is broken. It is considered that when the hydrogen concentration in the glass is high, more parts of the Si - O - Si bond are broken, chemical defects are easily generated, and the strength is reduced.

[0120] The above relational expression (I) holds in the region where the depth X from the outermost surface is 0.1 to 0.4 μm. The thickness of the compressive stress layer formed by ion exchange depends on the degree of chemical strengthening and is formed in the range of 5 to 50 μm. Moreover, the penetration depth of hydrogen in the glass depends on the diffusion coefficient, temperature, and time, and the penetration amount of hydrogen is also affected by the moisture content in the ambient gas in addition to these. The hydrogen concentration after chemical strengthening is the highest at the outermost surface and slowly decreases toward the deep part (main body) where the compressive stress layer is not formed. The above relational expression (I) stipulates the degree of its decrease. At the outermost surface (X = 0 μm), the moisture concentration may change due to aging over time, so it holds in the near-surface region (X = 0.1 to 0.4 μm) where it is considered that there is no such influence.

[0121] In formula (I), a is the slope that defines the degree of reduction of the hydrogen concentration. The range of a is from -0.150 to 0.010, preferably from -0.100 to 0.010, more preferably from -0.050 to 0.010.

[0122] In formula (I), b corresponds to the hydrogen concentration at the outermost surface (X = 0 μm). The range of b is from 0.000 to 0.220, preferably from 0.000 to 0.215, more preferably from 0.010 to 0.150, and further preferably from 0.010 to 0.100.

[0123] 〔Method for Measuring Hydrogen Concentration Distribution〕

[0124] Here, the hydrogen concentration distribution (H2O concentration, mol / L) of the glass is the distribution measured under the following analysis conditions.

[0125] The hydrogen concentration distribution of the glass substrate is measured using secondary ion mass spectrometry (SIMS). In the case of obtaining a quantitatively determined hydrogen concentration distribution by SIMS, a standard sample with a known hydrogen concentration is required. The method for producing the standard sample and the method for quantifying the hydrogen concentration are described below.

[0126] 1) Cut out a part of the glass substrate to be measured.

[0127] 2) Remove the region more than 50 μm from the surface of the cut glass substrate by grinding or chemical etching. The removal treatment is performed on both sides. That is, the removal thickness on both sides is more than 100 μm. The glass substrate after this removal treatment is used as the standard sample.

[0128] 3) Perform infrared spectroscopy (IR) on the standard sample, and find the absorbance height A of the peak near 3550 cm －1 and the absorbance height A of 4000 cm 3550 (baseline). －1 of the peak near 4000 (baseline).

[0129] 4) Measure the plate thickness d (cm) of the standard sample using a micrometer or other plate thickness measuring instrument.

[0130] 5) Referring to Document A, set the infrared actual absorption coefficient ε pract (L / (mol·cm)) of the glass H2O to 75, and use formula II to find the hydrogen concentration (in terms of H2O conversion, mol / L) of the standard sample.

[0131] Hydrogen concentration of the standard sample = (A 3550 - A 4000) / (ε pract ·d)···Formula II

[0132] Literature A) S. lievskiet al., Glastech. Ber. Glass Sci. Technol., 73(2000)39.

[0133] The glass substrate to be measured and the standard sample with a known hydrogen concentration obtained by the above method are simultaneously transported into the SIMS device, and measurements are carried out in sequence to obtain 1 H － and 30 Si － The depth-direction distribution of the intensities. Then, divide the 1 H － distribution by the 30 Si － distribution to obtain 1 H － / 30 Si － The depth-direction distribution of the intensity ratio. According to the 1 H － / 30 Si － depth-direction distribution of the intensity ratio, calculate the average 1 H － / 30 Si － intensity ratio in the region from a depth of 1 μm to 2 μm, and make a calibration curve of this value against the hydrogen concentration in a way that passes through the origin (the calibration curve under the standard sample of grade 1). Using this calibration curve, convert the 1 H － / 30 Si － intensity ratio on the vertical axis of the distribution of the glass substrate to be measured into the hydrogen concentration. Thus, the hydrogen concentration distribution of the glass substrate to be measured is obtained. It should be noted that the measurement conditions for SIMS and IR are as described below.

[0134] 〔Measurement conditions for SIMS〕

[0135] Device: ADEPT1010 manufactured by ULVAC-PHI

[0136] Primary ion species: Cs +

[0137] Acceleration voltage of the primary ion: 5 kV

[0138] Current value of the primary ion: 500 nA

[0139] Incident angle of the primary ion: 60° with respect to the normal of the sample surface

[0140] Scanning field range of primary ions: 300×300μm 2

[0141] Polarity of secondary ions: negative

[0142] Detection area of secondary ions: 60×60μm 2 (4% of the scanning field range of primary ions)

[0143] ESA Input Lens: 0

[0144] Use of neutralization gun: yes

[0145] Method for converting the horizontal axis from sputtering time to depth: Use a stylus surface profiler (Dektak150 manufactured by Veeco) to measure the depth of the analysis pit, and obtain the sputtering rate of primary ions. Use this sputtering rate to convert the horizontal axis from sputtering time to depth.

[0146] 1 H － Field Axis Potential during detection: It is possible that the optimum value varies according to each device. The measurer should pay attention to fully subtracting the background and set the value.

[0147] 〔Measurement conditions for IR〕

[0148] Device: Nic-plan / Nicolet 6700 manufactured by Thermo Fisher Scientific

[0149] Resolution: 4cm －1

[0150] Accumulation: 16

[0151] Detector: TGS detector

[0152] In order to derive the relational expression 〔I〕 from the hydrogen concentration distribution (H2O concentration, mol / L) of the glass measured according to the above analysis conditions, the following steps are carried out. Perform a linear approximation on the hydrogen concentration distribution in the depth range of 0.1~0.4μm. Use the obtained approximate straight-line equation as the relational expression 〔I〕. In addition, as a means of controlling a and b, for example, changing the flux concentration, sodium concentration, temperature, time, etc. in the ion exchange process can be cited.

[0153] This chemically strengthened glass preferably has a surface roughness (Ra) of 0.20nm or more. By making the surface roughness the above value or more, a chemically strengthened glass with higher surface strength can be manufactured. It is speculated that by making the glass surface have a certain degree of surface roughness, stress concentration is suppressed and the strength is increased.

[0154] The surface roughness can be measured, for example, by AFM surface observation in a measurement range of 1 μm × 1 μm.

[0155] It should be noted that the surface roughness of the conventional unpolished chemically strengthened glass plate is less than 0.20 nm.

[0156] 〔AFM measurement conditions〕

[0157] Device: Nanoscope V + MultiMode8 or Dimension ICON manufactured by Bruker

[0158] Mode: ScanAsyst mode

[0159] Detector: RTESPA (spring constant: 40 N / m)

[0160] Samples / lines: 256

[0161] Number of lines: 256

[0162] Scanning frequency: 1 Hz

[0163] Measurement field of view: 1 × 1 μm 2 (Aim at an area without contamination)

[0164] This chemically strengthened glass preferably has no grinding marks on the surface. Here, the grinding in this embodiment means smoothing the glass surface by grinding with abrasive grains. In addition, the presence or absence of grinding marks can be distinguished by surface observation using an AFM (Atomic Force Microscope). When there are no more than 2 scratches with a length of 5 μm or more and a width of 0.1 μm or more in a 10 μm × 5 μm area, it can be said that the surface has no grinding marks.

[0165] <<Breakage generation rate>>

[0166] The breakage generation rate of this chemically strengthened glass evaluated according to the strength test method of ISO20567-1 Test Method B is preferably 20% or less, more preferably 18% or less, further preferably 15% or less, and particularly preferably 13% or less. By making the above breakage generation rate 20% or less, the resistance to flying stones can be more effectively improved. n when calculating the breakage generation rate is 3 or more.

[0167] The scratch area of this chemically strengthened glass measured by the following method according to the strength test method of ISO20567-1 Test Method B is preferably 6% or less, more preferably 5.5% or less, and further preferably 5% or less.

[0168] (Method)

[0169] Measurement range: A range of 35×35 mm in the center of the sample

[0170] Image capture: Using a digital microscope (e.g., VHX-5000 manufactured by Keyence Corporation), capture an image of the sample after the flying stone test under a coaxial epi-illumination light source.

[0171] Extraction and area of scratches: Using a digital microscope (e.g., VHX-5000 manufactured by Keyence Corporation), binarize the captured image by brightness, extract the scratches on the surface of the sample, and take the value obtained by dividing the total area of the scratches by the area of the measurement range as the scratch area.

[0172] <<Drop ball strength>>

[0173] The drop ball strength of this chemically strengthened glass, measured by the following measurement test based on a 500 g iron ball, is preferably 20 cm or more, more preferably 40 cm or more, further preferably 60 cm or more, particularly preferably 64 cm or more, and most preferably 80 cm or more. The higher this drop ball strength, the better, and there is no particular limitation on the upper limit.

[0174] Measurement test: Drop a 500 g iron ball onto a glass substrate with a thickness of 2.0 mm or more made of the above-mentioned chemically strengthened glass, and increase the drop height sequentially until the glass substrate is broken. Measure the drop height at the time of breakage, and take the average value of the breakage heights of 5 test pieces as the drop ball strength.

[0175] The impact energy of this chemically strengthened glass, measured by the above measurement test through the drop ball test based on a 500 g iron ball, is preferably 3 J or more, more preferably 4 J or more, and further preferably 5 J or more. The higher this energy, the better.

[0176] The energy required to cause breakage of this chemically strengthened glass through the ice ball test is preferably 46 J or more, more preferably 89 J or more, further preferably 158 J or more, and particularly preferably 261 J or more. The higher the impact energy based on this ice ball, the better, and there is no particular limitation on the upper limit. The ice ball test is carried out by the following method in accordance with JIS C61215 (2020).

[0177] Test method: Make an ice ball collide with a glass of 100 mm×100 mm.

[0178] As a form of this chemically strengthened glass, it is preferable that even when a puck with a diameter of 55 mm collides at a speed of 33.9 m / s in the above-mentioned puck test, it does not break. As a form of this chemically strengthened glass, it is preferable that even when a puck with a diameter of 65 mm collides at a speed of 36.7 m / s in the above-mentioned puck test, it does not break. As a form of this chemically strengthened glass, it is preferable that even when a puck with a diameter of 75 mm collides at a speed of 39.5 m / s in the above-mentioned puck test, it does not break.

[0179] <<Breaking strength>>

[0180] The breaking strength of this chemically strengthened glass can be defined by the maximum value of the crack arrest lines or the difference between the maximum value and the minimum value of the crack arrest lines. A crack arrest line refers to a pattern generated when the progress of breakage temporarily stops, and the crack arrest line can be confirmed by observing the broken surface of the broken sample. Figure 5 It is a figure showing the crack arrest lines generated on the broken surface of the sample after the flying stone test. In Figure 5 it, the position where the flying stone collides with the sample surface 51 is taken as the collision point 52, the crack arrest lines are represented by dotted lines, the minimum value of the crack arrest lines is represented as the minimum crack arrest line 53, and the maximum value of the crack arrest lines is represented as the maximum crack arrest line 54.

[0181] As Figure 5 shown by the dotted line in, multiple crack arrest lines are generated by the repeated development and stop of cracks. The value of the crack arrest line is measured as the distance from the glass surface to the farthest position along the cutting surface of the glass in the vertical direction up to the generated crack arrest line.

[0182] In addition, the breaking strength can also be defined by the difference between the maximum value of the crack arrest lines and the maximum crack depth. The maximum crack depth is measured for the crack depths of the cutting surfaces of multiple unbroken chemically strengthened glasses, and the average value thereof is taken as the maximum crack depth (n≥3). That is, the larger the difference between the maximum value of the crack arrest lines and the maximum crack depth, the more abundant the margin before reaching breakage can be said to be. Hereinafter, the maximum value of the crack arrest lines is taken as the maximum crack arrest line depth, and the minimum value of the crack arrest lines is taken as the minimum crack arrest line depth.

[0183] <<Martens hardness MH>>

[0184] The Martens hardness MH of this chemically strengthened glass evaluated by PICODENTOR (registered trademark) of HM500 is preferably 3600 N / mm 2 or more, more preferably 3700 N / mm 2 or more, and further preferably 3750 N / mm 2 or more. From the viewpoint of being less likely to generate scratches, the higher this Martens hardness MH is, the better.

[0185] <<Glass composition>>

[0186] In this specification, the "parent composition of chemically strengthened glass" refers to the glass composition of the glass for chemical strengthening. Except in the case of extreme ion exchange treatment, the glass composition in the part deeper than the depth of the specific compressive stress layer of the chemically strengthened glass is almost the same as the parent composition of the chemically strengthened glass.

[0187] The parent composition of the chemically strengthened glass of this embodiment is expressed in mol% based on oxides, and preferably contains 52 to 75% of SiO2, 1 to 20% of Al2O3, and 1 to 20% of Na2O.

[0188] More preferably, the parent composition of the chemically strengthened glass of this embodiment is expressed in mol% based on oxides and contains 52 to 75% of SiO2, 1 to 20% of Al2O3, 0 to 18% of Li2O, 1 to 20% of Na2O, 0 to 5% of K2O, 0 to 20% of MgO, 0 to 20% of CaO, 0 to 20% of SrO, 0 to 20% of BaO, 0 to 10% of ZnO, 0 to 1% of TiO2, 0 to 8% of ZrO2, and 0 to 5% of Y2O3.

[0189] Hereinafter, the preferred glass compositions will be described.

[0190] In the glass for chemical strengthening of this embodiment, SiO2 is a component that forms the network structure of the glass. In addition, it is a component that improves chemical durability. The content of SiO2 is preferably 52% or more, more preferably 56% or more, further preferably 60% or more, and particularly preferably 64% or more. On the other hand, in order to have good meltability, the content of SiO2 is preferably 75% or less, more preferably 73% or less, further preferably 71% or less, and particularly preferably 69% or less.

[0191] Al2O3 is a component that increases the surface compressive stress generated by chemical strengthening and is essential. The content of Al2O3 is preferably 1% or more, more preferably 2% or more, further preferably 4% or more, and particularly preferably 6% or more. On the other hand, in order not to make the devitrification temperature of the glass too high, the content of Al2O3 is preferably 20% or less, more preferably 18% or less, and further preferably 17% or less, 16% or less in this order, and most preferably 15% or less.

[0192] Na2O is a component that improves the meltability of the glass and forms the surface compressive stress through ion exchange. The content of Na2O is preferably 1% or more, more preferably 2% or more, and particularly preferably 4% or more. If the amount of Na2O is too large, the chemical strengthening characteristics will be reduced. Therefore, the content of Na2O is preferably 20% or less, more preferably 18% or less, particularly preferably 16% or less, and most preferably 14% or less.

[0193] Similar to Na2O, K2O is also a component that reduces the melting temperature of glass and forms surface compressive stress through ion exchange. When K2O is contained, its content is preferably 0% or more, more preferably 0.1% or more, further preferably 0.3% or more, still further preferably 0.4% or more, and particularly preferably 0.5% or more. If there is too much K2O, the chemical strengthening property will be reduced, or the chemical durability will be reduced. Therefore, it is preferably 5% or less, more preferably 4.8% or less, further preferably 4.5% or less, particularly preferably 4.2% or less, and most preferably 4.0% or less.

[0194] From the viewpoint of improving the meltability of glass raw materials and forming surface compressive stress through ion exchange, the total content of Na2O and K2O, Na2O + K2O, is preferably 1% or more, more preferably 2% or more.

[0195] Li2O is a component that forms surface compressive stress through ion exchange. When Li2O is contained, its content is preferably 1% or more, more preferably 2% or more, further preferably 4% or more, and particularly preferably 5% or more. On the other hand, in order to make the glass stable, the content of Li2O is preferably 18% or less, more preferably 17% or less, further preferably 16% or less, and most preferably 15% or less.

[0196] If the ratio of the K2O content to the total content of Li2O, Na2O, and K2O (hereinafter referred to as R2O), K2O / R2O, is 0.2 or less, the chemical strengthening property can be improved and the chemical durability can be enhanced, so it is preferred. K2O / R2O is more preferably 0.15 or less, and further preferably 0.10 or less. It should be noted that R2O is preferably 10% or more, more preferably 12% or more, and further preferably 15% or more. In addition, R2O is preferably 20% or less, more preferably 18% or less.

[0197] MgO is a component that stabilizes the glass and also improves the mechanical strength and chemical resistance, so it is preferably contained when the content of Al2O3 is small, etc. The content of MgO is preferably 1% or more, more preferably 2% or more, further preferably 3% or more, and particularly preferably 4% or more. On the other hand, if MgO is added in excess, the viscosity of the glass will decrease, and devitrification or phase separation is likely to occur. The content of MgO is preferably 20% or less, more preferably 19% or less, further preferably 18% or less, and particularly preferably 17% or less.

[0198] CaO, SrO, BaO, and ZnO are all components that improve the meltability of glass and can be contained.

[0199] CaO is a component that improves the fusibility of glass and is a component that improves the pulverizability of chemically strengthened glass, and it may be contained. When CaO is contained, the content is preferably 0.5% or more, more preferably 1% or more, further preferably 2% or more, particularly preferably 3% or more, and most preferably 5% or more. On the other hand, if the content of CaO is greater than 20%, the ion exchange performance is significantly reduced, and thus it is preferably 20% or less. The content of CaO is more preferably 14% or less, and further preferably 10% or less, 8% or less, 6% or less, 3% or less, 1% or less in stages as follows.

[0200] SrO is a component that improves the fusibility of glass and is a component that improves the pulverizability of chemically strengthened glass, and it may be contained. When SrO is contained, the content is preferably 0.5% or more, more preferably 1% or more, further preferably 2% or more, particularly preferably 3% or more, and most preferably 5% or more. On the other hand, if the content of SrO is greater than 20%, the ion exchange performance is significantly reduced, and thus it is preferably 20% or less. The content of SrO is more preferably 14% or less, and further preferably 10% or less, 8% or less, 6% or less, 3% or less, 1% or less in stages as follows.

[0201] BaO is a component that improves the fusibility of glass and is a component that improves the pulverizability of chemically strengthened glass, and it may be contained. When BaO is contained, the content is preferably 0.5% or more, more preferably 1% or more, further preferably 2% or more, particularly preferably 3% or more, and most preferably 5% or more. On the other hand, if the content of BaO is greater than 20%, the ion exchange performance is significantly reduced. The content of BaO is preferably 20% or less, and more preferably 15% or less, 10% or less, 6% or less, 3% or less, 1% or less in stages as follows.

[0202] ZnO is a component that improves the fusibility of glass and may be contained. When ZnO is contained, the content is preferably 0.25% or more, more preferably 0.5% or more. On the other hand, if the content of ZnO is greater than 10%, the weather resistance of the glass is significantly reduced. The content of ZnO is more preferably 10% or less, and further preferably 8% or less, 6% or less, 3% or less, 1% or less in stages as follows.

[0203] ZrO2 is a component that improves mechanical strength and chemical durability and is preferably contained because it significantly increases CS. The content of ZrO2 is preferably 0.5% or more, more preferably 0.7% or more, further preferably 1.0% or more, particularly preferably 1.2% or more, and most preferably 1.5% or more. On the other hand, in order to suppress devitrification during melting, ZrO2 is preferably 8% or less, more preferably 7.5% or less, further preferably 7% or less, and particularly preferably 6% or less. If the content of ZrO2 is too high, the viscosity decreases due to an increase in the devitrification temperature. In order to suppress the deterioration of formability caused by the above-mentioned decrease in viscosity, when the forming viscosity is low, the content of ZrO2 is preferably 5% or less, more preferably 4.5% or less, and further preferably 3.5% or less.

[0204] In order to improve chemical durability, ZrO2 / R2O is preferably 0.02 or more, more preferably 0.04 or more, further preferably 0.06 or more, particularly preferably 0.08 or more, and most preferably 0.1 or more. ZrO2 / R2O is preferably 0.2 or less, more preferably 0.18 or less, further preferably 0.16 or less, and particularly preferably 0.14 or less.

[0205] TiO2 is not essential. When contained, it is preferably 0.05% or more, more preferably 0.1% or more. On the other hand, in order to suppress devitrification during melting, the content of TiO2 is preferably 1% or less, more preferably 0.5% or less, and further preferably 0.3% or less.

[0206] SnO2 is not essential. When contained, it is preferably 0.5% or more, more preferably 1% or more, further preferably 1.5% or more, and particularly preferably 2% or more. On the other hand, in order to suppress devitrification during melting, the content of SnO2 is preferably 4% or less, more preferably 3.5% or less, further preferably 3% or less, and particularly preferably 2.5% or less.

[0207] Y2O3 is a component that has the effect of making fragments less likely to fly off when chemically strengthened glass is broken and can be contained. The content of Y2O3 is preferably 0.3% or more, more preferably 0.5% or more, further preferably 0.7% or more, and particularly preferably 1.0% or more. On the other hand, in order to suppress devitrification during melting, the content of Y2O3 is preferably 5% or less, more preferably 4% or less.

[0208] B2O3 is a component that improves the chipping resistance of chemically strengthened glass or chemically strengthened glass and also improves the meltability, and can be contained. In order to improve the meltability, when containing B2O3, the content is preferably 0.5% or more, more preferably 1% or more, and further preferably 2% or more. On the other hand, if the content of B2O3 is too high, striae will be generated during melting, or phase separation is likely to occur, resulting in a reduction in the quality of the chemically strengthened glass. Therefore, it is preferably 10% or less. The content of B2O3 is more preferably 8% or less, further preferably 6% or less, and particularly preferably 4% or less.

[0209] La2O3, Nb2O5, and Ta2O5 are all components that make the fragments less likely to fly off when the chemically strengthened glass is broken, and can be contained in order to increase the refractive index. When containing these components, the total content of La2O3, Nb2O5, and Ta2O5 (hereinafter referred to as La2O3 + Nb2O5 + Ta2O5) is preferably 0.5% or more, more preferably 1% or more, further preferably 1.5% or more, and particularly preferably 2% or more. In addition, in order to prevent the glass from devitrifying during melting, La2O3 + Nb2O5 + Ta2O5 is preferably 4% or less, more preferably 3% or less, further preferably 2% or less, and particularly preferably 1% or less.

[0210] In addition, CeO2 can be contained. CeO2 sometimes suppresses coloring by oxidizing the glass. When containing CeO2, the content is preferably 0.03% or more, more preferably 0.05% or more, and further preferably 0.07% or more. In order to improve the transparency, the content of CeO2 is preferably 1.5% or less, more preferably 1.0% or less.

[0211] When the chemically strengthened glass is colored for use, coloring components can be added within the range that does not hinder the achievement of the desired chemical strengthening characteristics. As coloring components, for example, Co3O4, MnO2, Fe2O3, NiO, CuO, Cr2O3, V2O5, Bi2O3, SeO2, Er2O3, Nd2O3 can be cited.

[0212] The total content of the coloring components is preferably in the range of 1% or less. When it is desired to further improve the visible light transmittance of the glass, it is preferably substantially free of these components.

[0213] In order to improve the weather resistance to ultraviolet light irradiation, HfO2, Nb2O5, and Ti2O3 can be added. When added for the purpose of improving the weather resistance to ultraviolet light irradiation, in order to suppress the influence on other characteristics, the total content of HfO2, Nb2O5, and Ti2O3 is preferably 1% or less, further preferably 0.5% or less, and more preferably 0.1% or less.

[0214] In addition, as a fining agent during glass melting, etc., SO3, chlorides, and fluorides can be appropriately contained. If added in excess, it will affect the strengthening characteristics. Therefore, the total content of the components that function as fining agents, expressed as mass% on an oxide basis, is preferably 2% or less, more preferably 1% or less, and still more preferably 0.5% or less. There is no particular limitation on the lower limit. Typically, the total is preferably 0.05% or more, expressed as mass% on an oxide basis.

[0215] When using SO3 as a fining agent, if the content of SO3 is too small, no effect can be seen. Therefore, expressed as mass% on an oxide basis, it is preferably 0.01% or more, more preferably 0.05% or more, and still more preferably 0.1% or more. In addition, when using SO3 as a fining agent, the content of SO3, expressed as mass% on an oxide basis, is preferably 1% or less, more preferably 0.8% or less, and still more preferably 0.6% or less.

[0216] If added in excess, it will affect physical properties such as the strengthening characteristics. Therefore, when using Cl as a fining agent, the content of Cl, expressed as mass% on an oxide basis, is preferably 1% or less, more preferably 0.8% or less, and still more preferably 0.6% or less. In addition, if it is too small, no effect can be seen. Therefore, when using Cl as a fining agent, the content of Cl, expressed as mass% on an oxide basis, is preferably 0.05% or more, more preferably 0.1% or more, and still more preferably 0.2% or more.

[0217] When using SnO2 as a fining agent, the content of SnO2, expressed as mass% on an oxide basis, is preferably 1% or less, more preferably 0.5% or less, and still more preferably 0.3% or less. In addition, if it is too small, no effect can be seen. Therefore, when using SnO2 as a fining agent, the content of SnO2, expressed as mass% on an oxide basis, is preferably 0.02% or more, more preferably 0.05% or more, and still more preferably 0.1% or more.

[0218] It is preferably free of P2O5. When P2O5 is contained, it is preferably 2.0% or less, more preferably 1.0% or less, and most preferably not contained.

[0219] It is preferably free of As2O3. When Sb2O3 is contained, it is preferably 0.3% or less, more preferably 0.1% or less, and most preferably not contained.

[0220] <<Use>>

[0221] As uses of the chemically strengthened glass of the present invention, for example, there can be mentioned protective members for sensors mounted on mobile devices such as automobiles and trains, outdoor sensors, sensors mounted on surveillance cameras, etc., light-receiving panels of solar power generation modules, and outer surface members of buildings. Since the chemically strengthened glass of the present invention exhibits excellent resistance to flying stones, among these, it is preferably used as a protective member for sensors mounted on mobile devices, and more preferably used as a protective member for in-vehicle sensors. In Figure 1 FIGS. (a) and (b) of

[0222] Figure 1 FIG. (a) shows a structure in which a protective glass 10 is used for the lid portion of a cylindrical housing (protective member 1) that houses a sensor 20. Figure 1 FIG. (b) shows a structure in which glass is used for the spherical surface of a hemisphere that houses a sensor 20. Part or all of the protective member 1 is formed using the protective glass 10, and the protective glass 10 can be the chemically strengthened glass of the present invention.

[0223] As shown in Figure 1 FIG. (a), a support portion 2 for supporting the protective glass 10 may also be formed in a part of the protective member 1. The support portion 2 can be glass, or a metal such as stainless steel or corrosion-resistant aluminum can be used.

[0224] The protective member 1 is not limited to a cylindrical shape or a hemisphere, and can also be a three-dimensional shape such as a cylindrical shape, a prismatic shape, and a regular polyhedron of a spherical shape. In addition, the protective member 1 can be formed by laminating multiple glass sheets. When forming the support portion 2, an adhesive layer can be formed between the support portion 2 and the protective glass 10 to bond the support portion 2 and the protective glass 10.

[0225] <Manufacturing method of chemically strengthened glass>

[0226] The manufacturing method of the chemically strengthened glass of the present embodiment (hereinafter, also referred to as the present manufacturing method) is characterized by including the following steps (hereinafter, also abbreviated as step A): ion exchange is performed by bringing a chemically strengthening glass having a plate thickness greater than 2 mm into contact with an inorganic salt composition containing 80% by mass or more of potassium nitrate.

[0227] The chemical strengthening treatment for forming a compressive stress layer on the surface layer of the glass is a treatment in which a glass plate is brought into contact with an inorganic salt composition and metal ions in the glass are replaced with metal ions having an ionic radius larger than that of the metal ions present in the inorganic salt composition.

[0228] As a method of bringing glass into contact with an inorganic salt composition, examples include a method of applying a paste-like inorganic salt composition to glass, a method of spraying an aqueous solution of the inorganic salt composition onto glass, and a method of immersing glass in a salt bath of a molten salt of the inorganic salt composition heated to a temperature above the melting point. Among these methods, from the viewpoint of improving productivity, a method of immersing glass in a salt bath of a molten salt of the inorganic salt composition is preferred.

[0229] In this specification, the "inorganic salt composition" refers to a composition containing a molten salt. Examples of the molten salt contained in the inorganic salt composition include nitrates, sulfates, carbonates, chlorides, etc. Examples of nitrates include lithium nitrate, sodium nitrate, potassium nitrate, cesium nitrate, rubidium nitrate, silver nitrate, etc. Examples of sulfates include lithium sulfate, sodium sulfate, potassium sulfate, cesium sulfate, rubidium sulfate, silver sulfate, etc. Examples of chlorides include lithium chloride, sodium chloride, potassium chloride, cesium chloride, rubidium chloride, silver chloride, etc. These can be used alone or in combination of multiple kinds.

[0230] As the inorganic salt composition, it is preferably based on nitrate, and more preferably based on sodium nitrate or potassium nitrate. Here, "being based on" means that the content in the inorganic salt composition is 80% by mass or more.

[0231] <<Step A: A step of performing ion exchange by bringing chemically strengthened glass into contact with an inorganic salt composition containing 80% by mass or more of potassium nitrate>>

[0232] In the step of performing ion exchange by bringing an inorganic salt composition containing 80% by mass or more of potassium nitrate into contact with chemically strengthened glass, sodium ions in the glass are exchanged with potassium ions in the inorganic salt composition. The content of potassium nitrate in the inorganic salt composition used in this step is 80% by mass or more, preferably 85% by mass or more, more preferably 90% by mass or more, further preferably 95% by mass or more, particularly preferably 98% by mass or more, and most preferably 100%.

[0233] The inorganic salt composition in Step A may contain other inorganic salts in addition to potassium nitrate. Examples of other inorganic salts include potassium carbonate, potassium sulfate, potassium chloride, sodium nitrate, sodium carbonate, sodium sulfate, sodium chloride, among which sodium nitrate is preferred.

[0234] In Step A, the temperature of the inorganic salt composition in contact with the glass for chemical strengthening is preferably 360 °C or higher, more preferably 370 °C or higher, further preferably 380 °C or higher, and particularly preferably 390 °C or higher. In addition, from the viewpoint of improving the stone impact resistance, ball drop strength, and scratch resistance while maintaining good appearance quality after ion exchange, the temperature of the inorganic salt composition is preferably 500 °C or lower, more preferably 480 °C or lower, further preferably 465 °C or lower, and particularly preferably 455 °C or lower.

[0235] In Step A, the contact time between the glass for chemical strengthening and the inorganic salt composition is preferably 10 minutes to 30 hours. The contact time is more preferably 30 minutes or longer, further preferably 45 minutes or longer, and particularly preferably 1 hour or longer. By making the contact time 10 minutes or longer, the surface compressive stress can be increased. In addition, it is more preferably 24 hours or shorter, further preferably 16 hours or shorter, and particularly preferably 12 hours or shorter. By making this time 24 hours or shorter, the stone impact resistance, ball drop strength, and scratch resistance can be improved.

[0236] <<Step A'>>

[0237] As an embodiment of the above Step A, a method in which the above ion exchange includes the following Step A' can be cited, that is, the glass for chemical strengthening is brought into contact with an inorganic salt composition containing 80% by mass or more of potassium nitrate and containing at least one salt selected from K2CO3, Na2CO3, KHCO3, NaHCO3, K3PO4, Na3PO4, K2SO4, Na2SO4, KOH, and NaOH (hereinafter, this salt will also be referred to as a "flux") to obtain chemically strengthened glass.

[0238] (Ion exchange)

[0239] In Step A', for example, when K2CO3 is used as the above flux, when the content of the flux in the inorganic salt composition is 0.1% by mass or more and the chemical strengthening treatment temperature is 350 to 500 °C, the ion exchange treatment time is preferably 1 minute to 10 hours, more preferably 5 minutes to 8 hours, and further preferably 10 minutes to 4 hours.

[0240] From the aspect of controlling the surface hydrogen concentration, the addition amount of the flux in the inorganic salt composition is preferably 0.1% by mass or more, further preferably 0.5% by mass or more, more preferably 1% by mass or more, and particularly preferably 3% by mass or more. In addition, from the viewpoint of productivity, it is preferably below the saturation solubility of each salt. If added in excess, it may cause corrosion of the glass. For example, when K2CO3 is used as the flux, it is preferably 30% by mass or lower, more preferably 15% by mass or lower, and particularly preferably 10% by mass or lower.

[0241] In addition to potassium nitrate and the flux, the inorganic salt composition may also contain other chemical substances within the range that does not hinder the effects of the present invention. For example, alkali metal chlorides such as sodium chloride, potassium chloride, sodium borate, potassium borate, and alkali metal borates can be cited. These can be added individually or in combination of multiple kinds.

[0242] In the present embodiment, when performing step A' as the above-mentioned step A, it preferably includes: cleaning the chemically strengthened glass after the ion exchange step, acid-treating the chemically strengthened glass after the above-mentioned cleaning, and alkali-treating the chemically strengthened glass after the above-mentioned acid treatment. When performing cleaning, acid treatment, and alkali treatment, step A' refers to the step including the above-mentioned cleaning, acid treatment, and alkali treatment steps. The following describes the cleaning, acid treatment, and alkali treatment in the above-mentioned embodiment.

[0243] (Cleaning)

[0244] For cleaning, industrial water, ion-exchanged water, etc. are preferably used, and ion-exchanged water is more preferred. The cleaning conditions vary depending on the cleaning liquid used. When using ion-exchanged water, from the aspect of being able to completely remove the attached salts, it is preferably carried out at 0 to 100 °C.

[0245] (Acid treatment)

[0246] The acid treatment in step A' is carried out by immersing the chemically strengthened glass in an acidic solution, whereby Na and / or K on the surface of the chemically strengthened glass can be replaced with H. By performing the acid treatment, a low-density layer is formed on the surface layer of the chemically strengthened glass where the compressive stress layer is further metamorphosed, specifically, the density is reduced. The low-density layer is formed by the leaching (extraction) of Na and K from the outermost surface of the compressive stress layer and the entry (replacement) of H instead.

[0247] The solution is not particularly limited as long as it is acidic, and as long as the pH is less than 7. The acid used can be a weak acid or a strong acid. Specifically, acids such as nitric acid, hydrochloric acid, sulfuric acid, phosphoric acid, acetic acid, oxalic acid, carbonic acid, and citric acid are preferred, and nitric acid is more preferred. These acids can be used alone or in combination of multiple kinds.

[0248] The temperature for performing the acid treatment varies depending on the type or concentration of the acid used and the time, and it is preferably carried out at 100 °C or lower. The time for performing the acid treatment varies depending on the type or concentration of the acid used and the temperature, but from the aspect of productivity, it is preferably 10 seconds to 5 hours, and more preferably 1 minute to 2 hours. The concentration of the solution for performing the acid treatment varies depending on the type of acid used, the time, and the temperature, but a concentration with little concern about container corrosion is preferred. Specifically, it is preferably 0.1 to 20% by mass.

[0249] More specifically, for example, when nitric acid is used in the acid treatment, the content of nitric acid in the solution for the acid treatment is preferably 0.1 to 20% by mass, more preferably 0.5 to 10% by mass, the treatment temperature is preferably 20 to 80 °C, more preferably 40 to 70 °C, and the treatment time is preferably 1 to 60 minutes, more preferably 1 to 15 minutes.

[0250] Since the low-density layer is removed by the alkali treatment described below, the thicker the low-density layer, the easier it is to remove the glass surface. Therefore, from the viewpoint of the removal amount from the glass surface, the thickness of the low-density layer is preferably 5 nm or more, more preferably 20 nm or more. The thickness of the low-density layer can be controlled by the flux concentration, sodium concentration, temperature, time, etc. in the ion exchange process.

[0251] (Alkali treatment)

[0252] The alkali treatment in step A' is carried out by immersing the chemically strengthened glass in an alkaline solution, whereby a part or all of the low-density layer formed by the acid treatment can be removed.

[0253] The solution used in the alkali treatment is not particularly limited as long as it is alkaline, and as long as the pH is greater than 7, a weak base or a strong base can be used. Specifically, alkalis such as sodium hydroxide, potassium hydroxide, potassium carbonate, and sodium carbonate are preferred, and sodium hydroxide is more preferred. These alkalis can be used alone or in combination of multiple kinds.

[0254] The temperature for carrying out the alkali treatment varies depending on the type or concentration of the alkali used and the time, and is preferably 0 to 100 °C, more preferably 10 to 80 °C, and particularly preferably 20 to 60 °C. If it is within the above temperature range, there is no concern about glass corrosion, so it is preferred.

[0255] Although the time for carrying out the alkali treatment varies depending on the type or concentration of the alkali used and the temperature, from the aspect of productivity, it is preferably 10 seconds to 5 hours, more preferably 1 minute to 2 hours.

[0256] Although the concentration of the alkali contained in the solution for carrying out the alkali treatment varies depending on the type of the alkali used, the time, and the temperature, from the viewpoint of the removability from the glass surface, it is preferably 0.1 wt% to 20 wt%.

[0257] More specifically, for example, when sodium hydroxide is used in the alkali treatment, the content of sodium hydroxide in the solution for the alkali treatment is preferably 0.1 to 20% by mass, more preferably 0.5 to 10% by mass, the treatment temperature is preferably 20 to 80 °C, more preferably 40 to 70 °C, and the treatment time is preferably 1 to 60 minutes, more preferably 1 to 15 minutes.

[0258] By removing part or all of the low-density layer invaded by H through the above alkali treatment, the surface layer where the hydrogen concentration distribution satisfies the above specific relational expression (I) is exposed. Thus, chemically strengthened glass with further improved surface strength is obtained. In addition, since the scratches existing on the glass surface are also removed when the low-density layer is removed, it is considered that this point also contributes to the improvement of strength.

[0259] In step A', it is preferable to perform the above cleaning during the above acid treatment and alkali treatment and after the alkali treatment is completed.

[0260] In this manufacturing method, the ion exchange treatment can be a one-step treatment, or it can also be a two-step or more treatment (multi-step strengthening) under two or more different conditions. When the ion exchange treatment of this manufacturing method is multi-step strengthening, it can include a step of bringing the glass for chemical strengthening into contact with an inorganic salt composition mainly composed of sodium nitrate (hereinafter, also abbreviated as step B). In addition, step A' can be performed after the ion exchange without a flux (step A).

[0261] <<Step B: A step of performing ion exchange by bringing the glass for chemical strengthening into contact with an inorganic salt composition containing sodium nitrate as the main component>>

[0262] As the inorganic salt composition in step B, it contains sodium nitrate as the main component, and there is no particular limitation as long as the effects of the present invention are not impaired. The content of sodium nitrate in the inorganic salt composition is 30% by mass or more, preferably 50% by mass or more, more preferably 70% by mass or more, further preferably 90% by mass or more, particularly preferably 95% by mass or more, and most preferably 100%.

[0263] The inorganic salt composition in step B may contain other inorganic salts in addition to sodium nitrate. As other inorganic salts, for example, potassium nitrate, potassium carbonate, potassium sulfate, potassium chloride, sodium carbonate, sodium sulfate, sodium chloride, lithium nitrate, lithium carbonate, lithium sulfate, and lithium chloride can be mentioned. Among them, potassium nitrate is preferred.

[0264] In step B, the temperature of the inorganic salt composition in contact with the glass for chemical strengthening is preferably 360°C or higher, more preferably 370°C or higher, further preferably 380°C or higher, and particularly preferably 390°C or higher. In addition, from the viewpoint of improving the stone impact resistance, ball drop strength, and scratch resistance while maintaining good appearance quality after ion exchange, the temperature of the inorganic salt composition is preferably 500°C or lower, more preferably 460°C or lower, further preferably 430°C or lower, and particularly preferably 400°C or lower.

[0265] In Step B, the temperature of the inorganic salt composition in contact with the chemically strengthened glass, and the time for the chemically strengthened glass to be in contact with the inorganic salt composition are preferably 10 minutes to 24 hours. The contact time is more preferably 30 minutes or more, further preferably 45 minutes or more, and particularly preferably 1 hour or more. By making the contact time 10 minutes or more, the surface compressive stress can be increased. In addition, it is more preferably 12 hours or less, further preferably 8 hours or less, and particularly preferably 6 hours or less. By making this time 24 hours or less, the stone impact resistance, ball drop strength, and scratch resistance can be improved.

[0266] In the present embodiment, in addition to the chemical strengthening based on the above ion exchange treatment, physical strengthening can also be performed. As the conditions for physical strengthening, general heating and cooling strengthening methods can be used. For example, the methods described in Japanese Patent No. 6769441 and International Publication No. 2014 / 030682 can be cited.

[0267] In the present embodiment, when the above Step A' is not included as Step A, that is, when ion exchange is performed without the above flux in the inorganic salt composition, an etching treatment or a polishing treatment is preferably performed after Step A.

[0268] (Etching treatment)

[0269] The etching treatment is performed by bringing the chemically strengthened glass into contact with hydrofluoric acid (HF), or with hydrofluoric acid and other acids (for example, hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, etc.). As the etching treatment method, for example, known methods such as the dipping method, the spraying method, and the shower method can be cited, and the dipping method is preferred.

[0270] From the viewpoint of facilitating the time management of the etching amount, the concentration of hydrofluoric acid in the etching treatment liquid is preferably 1 to 10% by mass, more preferably 2 to 5% by mass. The etching amount based on the etching treatment is preferably 0.5 μm or more, more preferably 2 μm or more, further preferably 3 μm or more, and preferably 10 μm or less.

[0271] (Polishing treatment)

[0272] The polishing treatment is preferably performed using a polishing slurry containing polishing abrasive grains. As the polishing abrasive grains, for example, colloidal silica, cerium oxide, and various glass abrasives (for example, particles of styrene-based resin, acrylic-based resin, polyurethane-based resin, etc.) can be cited, and colloidal silica is preferred. From the viewpoint of further improving the flatness, the diameter of the polishing abrasive grains is preferably 5 to 300 nm, more preferably 10 to 200 nm.

[0273] The polishing slurry is preferably a so-called aqueous medium, and the slurry preferably contains water. In addition, it may contain water-soluble polymers, oligomers, and monomers. The pH of the polishing slurry is preferably 4 to 9. In order to stabilize the definite dispersibility of the particles in the polishing slurry, various dispersants can be appropriately added. As the solid content concentration of the polishing slurry, it is preferably 0.0001 to 20% by mass, more preferably 0.001 to 20% by mass. When the average particle diameter of the abrasive grains for polishing treatment is cerium oxide, it is preferably 0.1 μm or more, more preferably 0.5 μm or more, further preferably 1 μm or more, 2 μm or more, 3 μm or more in this order, and preferably 10 μm or less.

[0274] <<Glass for Chemical Strengthening>>

[0275] The glass for chemical strengthening that undergoes ion exchange in this manufacturing method is a lithium-containing aluminosilicate glass, an aluminosilicate glass, or a soda-lime glass. The preferred composition of the lithium-containing aluminosilicate glass, aluminosilicate glass, or soda-lime glass is the same as the composition described in the <<Composition>> section of <<Chemically Strengthened Glass>>. That is, it is preferably that the mother composition contains 52 to 75% of SiO2, 1 to 20% of Al2O3, and 1 to 20% of Na2O in terms of mole% based on oxides. The composition of the glass for chemical strengthening is consistent with the mother composition of the chemically strengthened glass obtained by chemically strengthening this glass for chemical strengthening.

[0276] As a manufacturing method of the glass for chemical strengthening, glass raw materials are appropriately formulated in such a way as to obtain a glass with a desired composition, heated and melted in a glass melting furnace, homogenized by bubbling, stirring, addition of clarifying agents, etc., formed into a glass plate with a specified thickness, and slowly cooled. Or it can also be formed into a plate shape by a method of forming into a block and cutting after slow cooling.

[0277] As a method of forming into a plate shape, for example, the float process, the pressing process, the melting process, and the down-draw process can be cited. Especially in the case of manufacturing a large-sized glass plate, the float process is preferred. In addition, continuous forming processes other than the float process can be cited, for example, the melting process and the down-draw process.

[0278] The chemically strengthened glass obtained by this manufacturing method preferably has a surface compressive stress CS0 of 400 to 1200 MPa, a compressive stress layer depth DOL - tail of 2.7 to 30.0 μm, an absolute value of the average slope of the stress curve from the surface to DOL - tail of 20 to 500 MPa / μm, and a tensile stress CT of 1.0 to 16 MPa. By satisfying the above ranges, excellent anti-flyrock property, ball-drop strength, and scratch resistance are exhibited.

[0279] In addition, the chemically strengthened glass may also be crystallized glass. In the case of crystallized glass, a crystallized glass containing one or more crystals selected from lithium silicate crystals, lithium aluminosilicate crystals, and lithium phosphate crystals is preferred. As the lithium silicate crystal, lithium metasilicate crystal, lithium disilicate crystal, etc. are preferred. As the lithium phosphate crystal, lithium orthophosphate crystal, etc. are preferred. As the lithium aluminosilicate crystal, β-spodumene crystal, petalite crystal, etc. are preferred.

[0280] In order to improve the mechanical strength, the crystallization rate of the crystallized glass is preferably 10% or more, more preferably 15% or more, further preferably 20% or more, and particularly preferably 25% or more. In addition, in order to improve transparency, it is preferably 70% or less, more preferably 60% or less, and particularly preferably 50% or less. A low crystallization rate is also excellent in terms of being easily bendable and moldable upon heating. The crystallization rate can be calculated by the Rietveld method based on the X-ray diffraction intensity. The Rietveld method is described in the "Crystallographic Analysis Handbook" edited by the Editorial Committee of the Crystallographic Society of Japan, "Crystallographic Analysis Handbook" (published by Kyoritsu Shuppan in 1999, p492-499).

[0281] <Solar power generation module>

[0282] The above-described chemically strengthened glass exhibits excellent anti-flyrock property, excellent anti-hail property, ball-drop strength, and scratch resistance, and can preferably be used as a component of a solar power generation module. The solar power generation module of the present embodiment includes a light-receiving panel and a solar cell substrate laminated in order from the light-receiving surface side toward the back surface side, and the light-receiving panel is the present chemically strengthened glass. The light-receiving panel has water resistance, fire resistance, durability, etc. The light-receiving panel has light transmittance for sunlight. The light transmitted through the light-receiving panel is obtained by the solar cell unit.

[0283] As one mode of the solar power generation module of the present embodiment, the 20° gloss of the light-receiving surface of the light-receiving panel is 100% or more, preferably 130% or more, more preferably 150% or more, and further preferably 170% or more. When a process that creates irregularities on a part of the glass is performed, minute cracks are generated on the surface of the glass, and the ball-drop strength decreases. Therefore, a state without irregularities is preferred, and by making the 20° gloss of the light-receiving surface 100% or more, more excellent ball-drop strength is exhibited.

[0284] As one mode of the solar power generation module of the present embodiment, the 60° gloss on the light-receiving surface of the light-receiving panel is 90% or more, preferably 110% or more, more preferably 130% or more, and further preferably 140% or more. By making the 60° gloss of the light-receiving surface 110% or more, the generation of minute cracks is suppressed, and more excellent ball-drop strength is exhibited.

[0285] As one mode of the solar power generation module of the present embodiment, the 85° glossiness of the light-receiving surface of the light-receiving panel is 80% or more, preferably 100% or more, and more preferably 120% or more. By making the 85° glossiness of the light-receiving surface 100% or more, the generation of minute cracks is suppressed, and excellent ball-drop strength is exhibited.

[0286] The glossiness can be measured in accordance with JIS Z8741:1997.

[0287] The arithmetic mean height Sa of the light-receiving surface of the present light-receiving panel is 10 nm or less, preferably 5 nm or less, more preferably 2 nm or less, further preferably 1 nm or less, and particularly preferably 0.5 or less. By making the arithmetic mean height Sa of the light-receiving surface 1 nm or less, the generation of minute cracks is suppressed, and more excellent ball-drop strength is exhibited. The arithmetic mean height Sa can be measured by a laser microscope.

[0288] The maximum height Sz of the light-receiving surface of the light-receiving panel of the solar power generation module of the present embodiment is preferably 10 nm or less, more preferably 5 nm or less, further preferably 1 nm or less, and particularly preferably 0.5 nm or less. By making Sz of the light-receiving surface 10 nm or less, the generation of minute cracks is suppressed, and more excellent ball-drop strength is exhibited. Sz can be measured by a laser microscope.

[0289] The root mean square height Sq of the light-receiving surface of the light-receiving panel of the solar power generation module of the present embodiment is preferably 10 nm or less, more preferably 5 nm or less, further preferably 1 nm or less, and particularly preferably 0.5 nm or less. By making Sq of the light-receiving surface 10 nm or less, the generation of minute cracks is suppressed, and more excellent ball-drop strength is exhibited. Sq can be measured by a laser microscope.

[0290] The arithmetic mean curvature Spc of the peak vertices of the light-receiving surface of the light-receiving panel of the solar power generation module of the present embodiment is preferably 100 nm or less, more preferably 20 nm or less, further preferably 10 nm or less, and particularly preferably 5 nm or less. By making Spc of the light-receiving surface 10 nm or less, the generation of minute cracks is suppressed, and excellent ball-drop strength is exhibited. Spc can be measured by a laser microscope.

[0291] The developed area ratio Sdr of the light-receiving surface of the light-receiving panel of the solar power generation module of the present embodiment is preferably 0.02 nm or less, more preferably 0.01 nm or less, and further preferably 0.001 nm or less. By making Sdr of the light-receiving surface 0.01 nm or less, the generation of minute cracks is suppressed, and more excellent ball-drop strength is exhibited. Sdr can be measured by a laser microscope.

[0292] Sa, Sz, Sq, Spc, and Sdr can be measured in accordance with ISO 25178.

[0293] The DOI (20) of the light-receiving surface of the light-receiving panel of the solar power generation module of the present embodiment is preferably 70% or more, more preferably 80% or more, still more preferably 90% or more, and particularly preferably 99% or more. By making the DOI (20) of the light-receiving surface 70% or more, the power generation efficiency can be further improved. The DOI can be measured in accordance with JIS K7374:2007.

[0294] The reflection haze value of the light-receiving surface of the light-receiving panel of the solar power generation module of the present embodiment is preferably 20% or less, more preferably 10% or less, still more preferably 5% or less, and particularly preferably 1% or less. By making the reflection haze value of the light-receiving surface 1% or less, the power generation efficiency can be further improved. The reflection haze value can be measured by using a spectrocolorimeter (for example, the RhopointIQ series manufactured by Konica Minolta).

[0295] As one aspect of the solar power generation module of the present embodiment, the Sn content in the range from the surface to a depth of 5 μm of the light-receiving surface of the light-receiving panel is 10 times or more, preferably 12 times or more, and more preferably 15 times or more the Sn content in the range from the surface to a depth of 5 μm of the surface of the light-receiving panel opposite to the light-receiving surface. There is no particular limitation on the upper limit, and the Sn content can be measured by SEM-EDX (EPMA). By making the Sn content in the range from the surface to a depth of 5 μm of the light-receiving surface of the light-receiving panel 10 times or more the Sn content in the range from the surface to a depth of 5 μm of the surface of the light-receiving panel opposite to the light-receiving surface, the ball-drop strength is improved, and an excellent protective effect against climates such as hail and falling objects is exhibited.

[0296] As one aspect of the solar power generation module of the present embodiment, the absolute value of the difference between CS0 of the light-receiving surface of the light-receiving panel and CS0 of the surface of the light-receiving panel opposite to the light-receiving surface is 10 MPa or more, preferably 12 MPa or more, more preferably 15 MPa or more, and still more preferably 20 MPa or more. By making the absolute value of the above difference 10 MPa or more, a compressive stress suitable for the fracture mode of the light-receiving surface and the fracture mode of the surface opposite to the light-receiving surface is obtained, and an excellent ball-drop strength is exhibited. There is no particular limitation on the upper limit of the absolute value of the above difference.

[0297] As one mode of the solar power generation module of the present embodiment, a solar power generation module including a light-receiving panel, a solar cell substrate, and a back panel is laminated in order from the light-receiving surface side toward the back surface side. The back panel is glass whose thickness is 1 mm or more thinner than that of the light-receiving panel. For example, physically strengthened glass, chemically strengthened glass, and non-strengthened glass can be cited. From the viewpoints of the weight and installation cost of the solar power generation module, the thickness of the back panel is preferably 1 mm or more thinner than that of the light-receiving panel, more preferably 2 mm or more thinner, and further preferably 3 mm or more thinner.

[0298] An antireflection film can be formed on the light-receiving surface of the light-receiving panel of the solar power generation module of the present embodiment. The light reflection of the light-receiving panel can be reduced, and the sunlight acquisition efficiency can be improved. In addition to the antireflection film, an antiglare film can also be formed on the light-receiving surface of the light-receiving panel.

[0299] Examples

[0300] Hereinafter, the present invention will be described based on examples, but the present invention is not limited thereto.

[0301] <Fabrication of Chemically Strengthened Glass>

[0302] Glass raw materials are formulated to have the following composition expressed as a molar percentage based on oxides, and 400 g is weighed based on the glass. Then, the mixed raw materials are put into a platinum crucible and placed in an electric furnace at 1500 to 1700 °C and melted for about 3 hours for defoaming and homogenization.

[0303] Glass Material A: SiO2 66.2%, Al2O3 11.2%, MgO 3.1%, CaO 0.2%, ZrO2 1.3%, Y2O3 0.5%, Li2O 10.4%, Na2O 5.6%, K2O 1.5%

[0304] Glass Material B: SiO2 70.64%, Al2O3 1.08%, MgO 6.88%, CaO 8.26%, ZrO2 0.10%, Na2O 12.8%, K2O 0.2%

[0305] In the examples shown in Tables 1 and 2, the obtained molten glass is poured into a metal mold, held at a temperature about 50 °C higher than the glass transition temperature for 1 hour, and then cooled to room temperature at a rate of 100 °C / minute to obtain a glass block. Glass plates with a plate thickness (mm) × 50 mm × 50 mm shown in Tables 1 and 2 are fabricated from the obtained glass block.

[0306] In the examples shown in Table 3, glass plates with a plate thickness (mm) × 50 mm × 50 mm shown in each table are fabricated from the formed glass plates by the float method, and in the examples shown in Table 4, by the roll pressing method.

[0307] <Evaluation of Chemical Strengthening Treatment and Chemically Strengthened Glass>

[0308] Using the glass plates obtained above, they were immersed in a molten salt composition under the conditions shown in Tables 1 to 4, and ion exchange treatment was carried out to produce the following chemically strengthened glasses of Examples 1 to 32.

[0309] It should be noted that after physical strengthening treatment of Examples 17, 19, 24, 26 and 30, chemical strengthening was carried out by ion exchange treatment shown in Table 3 or 4. The physical strengthening treatment was to raise the temperature to about 700 °C to reach near the softening point of the glass. After the temperature was stabilized, air was blown for air cooling strengthening.

[0310] For Example 31, the glass obtained by ion exchange treatment shown in Table 3 was immersed in 6 mass% HNO3 (nitric acid) at 60 °C for 10 minutes for acid treatment. Then, after washing with pure water several times, it was dried by blowing air. The resulting glass was immersed in 4 mass% NaOH (sodium hydroxide) at 60 °C for 10 minutes for alkali treatment. Then, after washing with pure water several times, it was dried by blowing air.

[0311] For Example 32, after ion exchange treatment shown in Table 3, it was immersed in a mixed aqueous solution of 2 mass% hydrofluoric acid (HF) and 15 mass% hydrochloric acid (HCl) for 1 μm etching treatment.

[0312] Examples 1 to 4, 10, 14, 18, 19, 21, 22, 25, 26, 29 to 32 are examples, and Examples 5 to 9, 11 to 13, 15, 16, 17, 20, 23, 24, 27 and 28 are comparative examples. In Tables 1 to 4, "-" indicates not evaluated, and cases where measurement could not be performed are recorded as 0.

[0313] The obtained chemically strengthened glass was evaluated according to the following method. The results are shown in Tables 1 to 4.

[0314] [Stress Measurement Using a Scattered Light Photoelastic Stress Meter]

[0315] Using a scattered light photoelastic stress meter (SLP-2000 manufactured by Orihara Seisakusho), the stress of the chemically strengthened glass was measured by the method described in International Publication No. 2018 / 056121. In addition, the stress curve was calculated using the attached software [SlpV (Ver. 2019.11.07.001)] of the scattered light photoelastic stress meter (SLP-2000 manufactured by Orihara Seisakusho).

[0316] The function for obtaining the stress curve is σ(x) = [a1 × erfc(a2 × x) + a3 × erfc(a4 × x) + a5]. a i (i (where \(n = 1 - 5\)) is a fitting parameter, and erfc is the complementary error function. The complementary error function is defined by the following formula.

[0317]

[0318] In the evaluation of this specification, the fitting parameters are optimized by minimizing the sum of the squares of the residuals between the obtained raw data and the above function. The measurement processing conditions are single time, and for the measurement area processing adjustment items, the surface specified selection edge method is used, the internal surface end specified selection is 6.0 μm, the internal left and right ends specified selection is automatic, the internal deep end specified selection is automatic (at the center of the sample film thickness), and the extension of the phase curve up to the center of the sample thickness is specified to select the fitting curve.

[0319] In addition, SEM-EDX (EPMA) is used simultaneously to measure the concentration distribution of alkali metal ions (sodium ions and potassium ions) in the cross-sectional direction, and it is confirmed that there is no contradiction with the obtained stress curve.

[0320] In addition, based on the obtained stress curve, the values of the compressive stress CS and the depth of the compressive stress layer DOL are calculated using the above method.

[0321] In each table, each mark represents the following meaning.

[0322] CS0: Compressive stress on the glass surface measured by FSM (MPa)

[0323] DOL: Depth of the compressive stress layer measured by FSM (μm) (linear approximation)

[0324] DOL-tail: Depth of the compressive stress layer measured by FSM (μm) (curvilinear approximation)

[0325] CTc: Tensile stress measured by FSM (MPa)

[0326] CS2: Compressive stress on the glass surface measured by SLP-2000 (MPa)

[0327] DOC: Depth of the compressive stress layer measured by SLP-2000 (μm)

[0328] CT: Maximum value of the tensile stress measured by SLP-2000 (MPa)

[0329] Absolute value of the surface layer slope: Absolute value of the average slope of the stress curve from the surface to DOL-tail (MPa / μm)

[0330] Average value of the deep layer slope from 50 μm to DOC: Absolute value of the average slope of the stress curve from a depth of 50 μm from the surface to DOC (MPa / μm)

[0331] Deep slope 400 - t / 2 average value: The absolute value of the average slope (MPa / μm) of the stress curve from a depth of 400 μm from the surface to the center of the plate thickness

[0332] ICT: Integral value of tensile stress CT (MPa·μm)

[0333] Light-receiving surface side: The light-receiving surface when glass is used as the light-receiving panel of a solar power generation module

[0334] Solar cell side: The surface opposite to the light-receiving surface when glass is used as the light-receiving panel of a solar power generation module

[0335] Maximum crack depth: The average value among samples of the measured value of the position from the surface of the deepest crack in the samples that did not break during the flying stone test (μm)

[0336] Minimum crack arrest line depth: The position where the crack first stops during the repeated progress and stop of the crack due to stone collision during the flying stone test (μm)

[0337] Maximum crack arrest line depth: The position where the crack finally stops during the repeated progress and stop of the crack due to stone collision during the flying stone test (μm)

[0338] Failure starting point: When the collision point of the flying stone with the glass is different from the failure starting point, it is the far side of the collision point

[0339] The stress curves of chemically strengthened glass (Examples 1 - 9) are shown in Figure 3 (a) - (f). Figure 3 (a) and (d) show the measurement results based on FSM, Figure 3 (b), (c), (e) and (f) show the measurement results based on SLP

[0340] [Flying stone test]

[0341] According to the strength test method of ISO20567 - 1 Test Method B, the flying stone test is carried out under the following conditions, and the fracture generation rate (n≥3) is calculated. The fracture generation rate is evaluated according to the following indicators in Tables 1 and 2. In addition, the glass subjected to the flying stone test is observed using microscopes (Keyence Corporation VK - X3000 and VHX - 5000), and the maximum scratch depth and the proportion of the scratch area are calculated

[0342] (Condition)

[0343] Flying stone: Iron grit

[0344] Stone size: 3.55 - 5 mm

[0345] Ejection amount: 500 g

[0346] Injection pressure: 200 kPa

[0347] Sample setting angle: 54°

[0348] Injection time: 8 - 12 s

[0349] Injection times: 2

[0350] Sample collision area: 40×40 mm

[0351] In addition, the fracture generation rate, maximum scratch depth, and scratch area are calculated as follows.

[0352] (Fracture generation rate)

[0353] Fracture generation rate: Number of fractured samples in the flying stone test / Total number of evaluated samples

[0354] Judgment of sample fracture: There are cracks on the surface of the sample after the flying stone test that extend beyond the range of each scratch.

[0355] (Maximum scratch depth)

[0356] Selection of scratches for evaluation: Select three or more visually larger scratches from the multiple scratches remaining on the surface of the sample after the flying stone test.

[0357] Scratch depth measurement: Use a laser microscope VK-X3000 (manufactured by Keyence Corporation) equipped with a white light interferometer to scan the microscopic shape of the selected scratch with a laser and record the depth at the deepest position.

[0358] Maximum scratch depth: Take the maximum value among the measured depths of multiple scratches as the maximum scratch depth.

[0359] (Scratch area)

[0360] Measurement range: A range of 35×35 mm in the center of the sample

[0361] Image capture: Use a microscope VHX-5000 (manufactured by Keyence Corporation) to capture an image of the sample after the flying stone test under a coaxial epi-illumination light source.

[0362] Extraction and area of scratches: Use VHX-5000 (manufactured by Keyence Corporation) to binarize the captured image by brightness, extract the scratches on the surface of the sample, and take the value obtained by dividing the total area of the scratches by the area of the measurement range as the scratch area.

[0363] (Evaluation index)

[0364] A: Fracture generation rate is 0% and scratch area is 6% or less

[0365] B: The fracture generation rate is 0% and the scratch area is greater than 6%.

[0366] C: The fracture generation rate is greater than 0% and less than or equal to 20% and the scratch area is less than or equal to 6%.

[0367] D: The fracture generation rate is greater than 0% and less than or equal to 20% and the scratch area is greater than 6%.

[0368] E: The fracture generation rate is greater than 20% and less than or equal to 100%.

[0369] [Breaking strength]

[0370] The breaking strength was measured by the following method. For the samples of Examples 2, 4, and 7 to 9 on which the flying stone test was performed, the maximum crack depth, the minimum crack arrest line depth, and the maximum crack arrest line depth were measured respectively. The results are shown in Tables 1 and 2.

[0371] The figures obtained by photographing the appearance of the samples of Examples 1, 2, 7, and 15 on which the flying stone test was performed using a digital camera (EOS Kiss X6i manufactured by Canon Inc.) are shown in Figure 4 .

[0372] [Drop ball strength]

[0373] The drop ball strength was measured by the following method.

[0374] For Tables 1 and 2, a 500 g iron ball was dropped onto a 3.2 mm thick glass substrate made of the above chemically strengthened glass, and the drop height was increased successively until the glass substrate was broken. The drop height at the time of breakage was measured, and the average of the breakage heights for 5 test pieces was taken as the drop ball strength. The evaluation of the drop ball strength is as follows, ◎: The average breakage height is 60 cm or more, 〇: The average breakage height is 40 cm or more and less than 60 cm, △: The average breakage height is 20 cm or more and less than 40 cm, ×: The average breakage height is less than 20 cm.

[0375] For Tables 3 and 4, a 500 g iron ball and a 900 g iron ball were dropped onto a 3.2 mm thick glass substrate made of the above chemically strengthened glass, and the drop height was increased successively until the glass substrate was broken. The drop height at the time of breakage was measured, and the average of the breakage heights for 5 test pieces was taken as the drop ball strength. In addition, a 500 g iron ball and a 900 g iron ball were dropped onto the above glass substrate, and the average of the energies at the time of breakage for 5 test pieces was calculated from the formula of the mass of each drop ball × g × height and taken as the collision energy.

[0376] For Tables 3 and 4, a puck (with a diameter of 55 mm, 65 mm, or 75 mm) was made to collide with a glass substrate with a thickness of 3.2 mm composed of the above-mentioned chemically strengthened glass by the following test method. Five test pieces were tested, and the fracture generation rate was obtained.

[0377] Method: Make the puck collide with a 100 mm × 100 mm glass.

[0378] The dropping speeds and energies of the pucks with each diameter are as described below.

[0379] Puck with a diameter of 55 mm: dropping speed 33.9 m / s, energy 46 J

[0380] Puck with a diameter of 65 mm: dropping speed 36.7 m / s, energy 89 J

[0381] Puck with a diameter of 75 mm: dropping speed 39.5 m / s, energy 158 J

[0382] [Appearance characteristics]

[0383] The glossiness, DOI (image definition), and reflection haze value were measured by the following method using an appearance analyzer (Rhopoint IQ, manufactured by Konica Minolta).

[0384] (Glossiness)

[0385] The glossiness was measured according to JIS Z8741:1997 at incident angles of 20°, 60°, and 85°.

[0386] (DOI)

[0387] The image definition (DOI(20)) was measured according to JIS K 7374:2007.

[0388] (Reflection haze value)

[0389] The reflection haze value was measured using the Rhopoint IQ series manufactured by Konica Minolta.

[0390] [Evaluation based on a variable-angle spectrophotometer]

[0391] Measurement was carried out by the following method using a variable-angle spectrophotometer (GC5000L, manufactured by Nippon Denshoku Industries Co., Ltd.).

[0392] (Transmission at 0 degrees)

[0393] The value of transmission at 0 degrees is the value obtained by measuring the brightness vertically transmitted through the substrate and comparing it with a standard transparent substrate. The value of "Total" is obtained by measuring the brightness distribution while changing the light-receiving part in the range of -90° to +90°.

[0394] The value of the resolution index T in Tables 3 and 4 was measured according to the method described in Japanese Patent Publication No. 5867649.

[0395] (45-degree reflection)

[0396] The value of the 45-degree reflection is the relative luminance ratio obtained by measuring the regular reflection luminance of light incident on the substrate at an angle of 45° and comparing it with a standard substrate. The value of "Total" was calculated by measuring the luminance distribution while changing the light-receiving part in the range of 0° to +90°. The value of the reflection image diffusivity index R in Tables 3 and 4 was measured according to the method described in Japanese Patent Publication No. 5867649.

[0397] [Bidirectional Reflectance Distribution Function (BRDF)]

[0398] Using (image sensor type 3D BRDF / BTDF measuring instrument series Mini-Diff V2, manufactured by Synopsys), the light source color is green (center wavelength 525 nm), placed on a black felt (reflectivity approximately 0%), and the BRDF value was measured for a glass monomer (evaluation area 20 mm × 20 mm) in a way that includes back reflection. The luminance was measured at incident angles of 0°, 20°, 40°, and 60° to show half of the solid angle width.

[0399] [Surface roughness]

[0400] The values of Sa and Sz were measured using a laser microscope (Keyence Corporation, VK-X3000, laser microscope mode) at ×10, 3 mm × 3 mm under the following conditions.

[0401] · Output data with a resolution of Z step = 0.1 nm (measured actually at Z step = 3 μm and supplemented in RPD2 mode)

[0402] · Field of view of 4 mm × 3 mm (measured for 3 × 3 fields of view with an objective lens of ×10, connection mode)

[0403] · Spatial resolution of XY step ≈ 2.8 μm, approximately 1405 × 1054 pixel image

[0404] [Martens hardness]

[0405] As the measuring device, PICODENTOR (registered trademark) of HM500 was used, and according to the following conditions, a total of 3 locations at the center and near the center of the glass plate were measured, and the average value of the 3 measured values was used as the Martens hardness.

[0406] Indentation load: 500 mN

[0407] Holding time: 5 seconds

[0408] Loading speed and unloading speed: 100 mN / sec

[0409] [Hydrogen concentration]

[0410] Measure the hydrogen concentration distribution according to the method described in the above-mentioned [Method for Measuring Hydrogen Concentration Distribution], and derive the relational expression [I]. Measure the hydrogen concentration distributions of Example 21 and Example 31. As a result, in Example 21, a is -0.166 and b is 0.134, and in Example 31, a is 0.003 and b is 0.016.

[0411] [Polishing marks]

[0412] Identify the presence or absence of polishing marks by surface observation using an AFM (Atomic Force Microscope). For Example 31, observe the surface scratches. As a result, in a 10 μm × 5 μm area, there are no more than 2 scratches with a length of 5 μm or more and a width of 0.1 μm or more, indicating a state without polishing marks on the surface.

[0413] [Surface roughness (Ra)]

[0414] Measure the surface roughness Ra using an AFM under the following measurement conditions.

[0415] AFM measurement conditions: Atomic Force Microscope (XE - HDM; manufactured by Park systems), scanning size: 1 μm × 1 μm, color scale: ±1 nm, scanning speed: 1 Hz.

[0416] Measure Ra for Example 31, and the result is 0.40 nm or more.

[0417] [Table 1]

[0418]

[0419] [Table 2]

[0420]

[0421] [Table 3]

[0422] Table 3

[0423]

[0424] [Table 4]

[0425] Table 4

[0426]

[0427] As shown in Tables 1 to 4 and Figure 4As shown, Examples 1 to 4, 10, 14, 18, 19, 21, 22, 25, 26, 29 to 32 as embodiments showed excellent flying stone resistance, ball drop strength, and scratch resistance compared with the comparative examples. Example 31 in which Process A' was performed and Example 32 in which an etching process was performed after Process A showed more excellent ball drop strength. In addition, Examples 2 and 4 as embodiments showed excellent breaking strength compared with Comparative Examples 7, 8, and 9.

[0428] It should be noted that this application is based on Japanese Patent Application No. 2022-182870 filed on November 15, 2022, Japanese Patent Application No. 2023-54157 filed on March 29, 2023, and Japanese Patent Application No. 2023-170427 filed on September 29, 2023, the contents of which are incorporated herein by reference.

[0429] Symbol Explanation

[0430] 1 Protection member

[0431] 2 Indication part

[0432] 5 Mounting part

[0433] 10 Protection glass

[0434] 20 Sensor

[0435] 30 Camera

Claims

1. A chemically strengthened glass having a plate thickness greater than 2 mm, a surface compressive stress CS0 of 400 to 1200 MPa, a depth of the compressive stress layer DOL-tail of 2.7 to 30.0 μm, an absolute value of the average slope of the stress curve from the surface to DOL-tail of 20 to 500 MPa / μm, and a tensile stress CT of 1.0 to 16 MPa.

2. The chemically strengthened glass according to claim 1, wherein, The absolute value of the average slope of the stress curve from a position 50 μm from the surface to DOC is 0.00 to 0.90 MPa / μm.

3. The chemically strengthened glass according to claim 1, wherein, The difference between the average Na concentration at a depth of 25 to 30 μm from the surface and the Na concentration at the center of the plate thickness is 1% or less, expressed as a molar percentage based on oxides.

4. The chemically strengthened glass according to claim 1, wherein, The integrated value of the tensile stress is 20000 MPa·μm or less.

5. The chemically strengthened glass according to claim 1, which is a lithium-containing aluminosilicate glass.

6. The chemically strengthened glass according to claim 1, wherein, The absolute value of the difference between the maximum crack arrest line depth and the minimum crack arrest line depth is 650 μm or more.

7. The chemically strengthened glass according to claim 1, wherein, The absolute value of the difference between the maximum crack arrest line depth and the maximum crack depth is 40 μm or more.

8. The chemically strengthened glass according to any one of claims 1 to 7, wherein, The fracture generation rate evaluated according to the strength test method of Test Method B of ISO 20567-1 is 20% or less.

9. The chemically strengthened glass according to any one of claims 1 to 7, wherein, The ball drop strength measured with a 500 g iron ball is 64 cm or more.

10. The chemically strengthened glass according to any one of claims 1 to 7, wherein, The plate thickness is 10 mm or less.

11. The chemically strengthened glass according to any one of claims 1 to 7, wherein, The surface roughness Ra is 0.20 nm or more. The hydrogen concentration Y in the region at a depth X from the outermost surface of the glass satisfies the following relational expression (I) when X = 0.1 to 0.4 μm, and the surface has no grinding marks. Y = aX + b (I) The meanings of the symbols in formula (I) are as follows. Y: Hydrogen concentration in terms of H2O conversion, unit is mol / L X: Depth from the outermost surface of the glass, unit is μm a：－0.150～0.010 b：0.000～0.220。 12. The chemically strengthened glass according to any one of claims 1 to 7, which is for vehicle-mounted sensors.

13. A method for manufacturing a chemically strengthened glass, comprising the following steps: contacting a chemically strengthening glass having a plate thickness greater than 2 mm with an inorganic salt composition containing 80 mass% or more of potassium nitrate for ion exchange.

14. The manufacturing method of the chemically strengthened glass according to claim 13, wherein, The ion exchange is to contact the chemically strengthening glass with an inorganic salt composition containing 80 mass% or more of potassium nitrate and containing at least one salt selected from K2CO3, Na2CO3, KHCO3, NaHCO3, K3PO4, Na3PO4, K2SO4, Na2SO4, KOH, and NaOH to obtain a chemically strengthened glass, and further includes the following steps: After the ion exchange, cleaning the chemically strengthened glass. After the cleaning, performing acid treatment on the chemically strengthened glass. After the acid treatment, performing alkali treatment on the chemically strengthened glass.

15. The manufacturing method of the chemically strengthened glass according to claim 13 or 14, wherein, The surface compressive stress CS0 of the chemically strengthened glass is 400 to 1200 MPa, the depth of the compressive stress layer DOL-tail is 2.7 to 30.0 μm, the absolute value of the average slope of the stress curve from the surface to DOL-tail is 20 to 500 MPa / μm, and the tensile stress CT is 1.0 to 16 MPa.

16. The method for manufacturing chemically strengthened glass according to claim 13 or 14, wherein, The chemically strengthening glass is a lithium-containing aluminosilicate glass.

17. The chemically strengthened glass according to any one of claims 1 to 7, wherein, When the plate thickness is greater than 2 mm and less than 10 mm, when the plate thickness is set as T, the depth of the compressive stress layer DOL-tail is 0.03T or less.

18. The chemically strengthened glass according to any one of claims 1 to 7, wherein, When the plate thickness is greater than 2 mm and less than 10 mm, DOL-tail is 10 μm or less.

19. The chemically strengthened glass according to any one of claims 1 to 7, wherein, The tensile stress CT is 1.0 to 4.0 MPa.

20. The chemically strengthened glass according to any one of claims 1 to 7, wherein The absolute value of the average slope of the stress curve from the surface to DOL-tail is 50 to 200 MPa / μm.

21. The chemically strengthened glass according to any one of claims 1 to 7, wherein, The impact energy measured by the drop ball test based on a 500 g iron ball is 3 J or more.

22. The chemically strengthened glass according to any one of claims 1 to 7, in the ice hockey test, does not break even when an ice hockey with a diameter of 55 mm collides at a speed of 33.9 m / s, wherein, The ice hockey test is carried out according to the following method. Method: Make the ice hockey collide with a 100 mm × 100 mm glass.

23. The Martens hardness MH of the chemically strengthened glass according to any one of claims 1 to 7 is 3600 N / mm or more when evaluated using HM500 with the registered trademark PICODENTOR. 2 The above.

24. A solar power generation module, which sequentially stacks a light-receiving panel and a solar cell substrate from the light-receiving surface side toward the back surface side. The light-receiving panel is the chemically strengthened glass according to any one of claims 1 to 7. The Sa of the light-receiving surface of the light-receiving panel is 10 nm or less and the 20° glossiness is 100% or more.

25. A solar power generation module, which sequentially stacks a light-receiving panel and a solar cell substrate from the light-receiving surface side toward the back surface side. The light-receiving panel is the chemically strengthened glass according to any one of claims 1 to 7. The Sn content in the range from the surface to a depth of 5 μm on the light-receiving surface of the light-receiving panel is 10 times or more of the Sn content in the range from the surface to a depth of 5 μm on the surface of the light-receiving panel opposite to the light-receiving surface.

26. A solar power generation module, which sequentially stacks a light-receiving panel, a solar cell substrate and a back panel from the light-receiving surface side toward the back surface side. The light-receiving panel is the chemically strengthened glass according to any one of claims 1 to 7. The absolute value of the difference between CS0 of the light-receiving surface of the light-receiving panel and CS0 of the surface of the light-receiving panel opposite to the light-receiving surface is 10 MPa or more.

27. A solar power generation module, which sequentially stacks a light-receiving panel, a solar cell substrate and a back panel from the light-receiving surface side toward the back surface side. The light-receiving panel is the chemically strengthened glass according to any one of claims 1 to 7. The back panel is a glass whose thickness is 1 mm or more thinner than that of the light-receiving panel.

28. The chemically strengthened glass according to any one of claims 1 to 7, wherein, It has a first main surface, a second main surface opposite to the first main surface, and an end. In either the first main surface or the second main surface, the shape of one of the four corners is different or the shapes of the four corners are different from each other. The end is chamfered with a C or an R.

29. A building, which includes the chemically strengthened glass according to any one of claims 1 to 7 as an outer surface component.

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