Cover glass of in-vehicle display

Abstract

To provide a technique that, in a cross-section orthogonal to a separation line on a main surface, enables extension of a crack in a direction perpendicular to the main surface, from the tip of a crack that extends obliquely with respect to the main surface from the separation line.SOLUTION: A cover glass of an in-vehicle display includes a first main surface, a second main surface that is opposite to the first main surface, at least one of a first inclined surface that intersects the first main surface at an obtuse angle in a cross-section that is orthogonal to a peripheral edge of the first main surface and a second inclined surface that intersects the second main surface at an obtuse angle in the cross-section, and an end surface that extends in a direction perpendicular to the first main surface from at least one of respective tips of the first inclined surface and the second inclined surface. An arithmetic average roughness of at least one of the first inclined surface and the second inclined surface is less than 0.1 μm, and an arithmetic average roughness of at least a portion of the end surface is 0.1 μm or greater, and the first main surface is installed inside a vehicle toward an occupant of the vehicle.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a cover glass for an in-vehicle display.

Background Art

[0002] In Patent Documents 1 and 2, the glass plate is separated by a separation line that separates the main surface of the glass plate into two regions. Specifically, first, the irradiation point of the laser beam is moved along the separation line, and cracks extending obliquely from the separation line in a direction oblique to the main surface are formed in a cross section perpendicular to the separation line.

[0003] In Patent Document 1, the separation line intersects obliquely with the periphery of the main surface, and the intersection point is the starting point of the movement of the irradiation point. Thereby, cracks extending obliquely from the separation line in a direction oblique to the main surface can be formed in a cross section perpendicular to the separation line.

[0004] On the other hand, in Patent Document 2, the irradiation point has a power density distribution that is asymmetric about the left and right. The left-right direction is a direction parallel to the main surface and perpendicular to the separation line. Thereby, cracks extending obliquely from the separation line in a direction oblique to the main surface can be formed in a cross section perpendicular to the separation line.

[0005] According to Patent Documents 1 and 2, as described above, cracks extending obliquely from the separation line in a direction oblique to the main surface are obtained in a cross section perpendicular to the separation line. Since an inclined surface corresponding to the chamfered surface is obtained, chamfering is unnecessary.

[0006] On the other hand, in Patent Documents 3 and 4, the laser beam is linearly focused inside the glass plate to form a linear damaged portion. The linear damaged portion extends in a direction perpendicular to the main surface. If cracks are formed starting from the damaged portion, an end surface extending perpendicularly from the main surface can be obtained.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

[0008] According to Patent Documents 1 and 2, as described above, cracks extending in an oblique direction with respect to the main surface are formed from the separation line in a cross section orthogonal to the separation line. Therefore, an inclined surface corresponding to the chamfered surface can be obtained without performing chamfering.

[0009] By the way, in Patent Documents 1 and 2, after the formation of the cracks, stress is applied to the glass plate to generate new cracks from the tips of the cracks. At that time, the new cracks sometimes do not extend in a direction perpendicular to the main surface.

[0010] On the other hand, according to Patent Documents 3 and 4, the linear damaged portion extends in a direction perpendicular to the main surface. Therefore, if a crack is formed starting from the damaged portion, an end surface extending perpendicularly from the main surface can be obtained. However, since the angle between the main surface and the end surface is perpendicular, chamfering is required.

[0011] One aspect of the present disclosure provides a technique capable of extending a crack in a direction perpendicular to the main surface from the tip of a crack extending in an oblique direction with respect to the main surface from a separation line in a cross section orthogonal to the separation line of the main surface. [Means for Solving the Problems]

[0012] The cover glass of the in-vehicle display according to one aspect of the present disclosure has a first main surface, a second main surface opposite to the first main surface, a first inclined surface that intersects the first main surface at an obtuse angle in a cross section perpendicular to the periphery of the first main surface, one or more of a second inclined surface that intersects the second main surface at an obtuse angle in the cross section, and an end surface extending in a direction perpendicular to the first main surface from one or more tips of one or more of the first inclined surface and the second inclined surface. The arithmetic mean roughness of one or more of the first inclined surface and the second inclined surface is less than 0.1 μm, and the arithmetic mean roughness of at least a part of the end surface is 0.1 μm or more. The first main surface is installed inside the vehicle facing the vehicle occupants.

Effect of the Invention

[0013] According to one aspect of the present disclosure, in a cross section perpendicular to the separation line of the main surface, a crack can be extended in a direction perpendicular to the main surface from the tip of a crack extending obliquely from the separation line to the main surface.

Brief Description of the Drawings

[0014]

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DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In each drawing, the same or corresponding components are denoted by the same reference numerals, and the description thereof may be omitted. In the specification, "~" indicating a numerical range means that the numerical values described before and after it are included as the lower limit value and the upper limit value.

[0016] (First Embodiment) As shown in FIG. 1, the method for processing a glass plate includes S1 to S4. Hereinafter, with reference to FIGS. 2A to 2E, a first example of S1 to S4 in FIG. 1 will be described.

[0017] First, in S1 of FIG. 1, as shown in FIG. 2A, a glass plate 10 is prepared. The glass plate 10 may be a bent plate, but in this embodiment, it is a flat plate. The glass plate 10 has a first main surface 11 and a second main surface 12 opposite to the first main surface 11.

[0018] The shapes of the first main surface 11 and the second main surface 12 are, for example, rectangular. Note that the shapes of the first main surface 11 and the second main surface 12 may be trapezoidal, circular, elliptical, etc., and are not particularly limited.

[0019] The use of the glass plate 10 is, for example, automotive window glass, instrument panel, head-up display (HUD), dashboard, center console, cover glass for automotive interior parts such as shift knobs, architectural window glass, display substrate, or display cover glass. The thickness of the glass plate 10 is appropriately set according to the use of the glass plate 10, and is, for example, 0.01 cm to 2.5 cm.

[0020] After S1 to S4 in FIG. 1, the glass plate 10 may be laminated with another glass plate via an intermediate film and used as laminated glass. Further, after S1 to S4 in FIG. 1, the glass plate 10 may be subjected to strengthening treatment and used as tempered glass.

[0021] The glass plate 10 is, for example, soda-lime glass, alkali-free glass, chemically strengthened glass, etc. Chemically strengthened glass is used as, for example, a cover glass after being chemically strengthened. The glass plate 10 may be air-cooled strengthened glass.

[0022] The glass plate 10 may be bent and formed after S1 to S4 in FIG. 1.

[0023] Next, in S2 of FIG. 1, as shown in FIG. 2B, the irradiation point of the first laser beam LB1 is moved along the first separation line BL1 to form the first crack CR1. The first separation line BL1 separates the first main surface 11 into two regions. The first crack CR1 extends obliquely from the first separation line BL1 toward the first main surface 11 in a cross-section orthogonal to the first separation line BL1.

[0024] When the first crack CR1 is formed, a second crack CR2 is also formed. The second crack is formed along the second separation line BL2. The second separation line BL2 separates the second main surface 12 into two regions. The second crack CR2 extends obliquely from the second separation line BL2 toward the second main surface 12 in a cross-section orthogonal to the second separation line BL2.

[0025] The first laser beam LB1 passes through the glass plate 10 from the irradiation point on the first main surface 11 to the irradiation point on the second main surface 12. The first crack CR1 and the second crack CR2 are formed simultaneously by the thermal stress of the glass. As the formation method, for example, the methods described in Patent Document 1 or Patent Document 2 are used.

[0026] In this embodiment, both the first crack CR1 and the second crack CR2 are generated simultaneously by the irradiation of the first laser beam LB1, but only one of them may be generated. In that case, the first crack CR1 and the second crack CR2 may be generated in order. However, it is not necessary to generate only one of the first crack CR1 and the second crack CR2 and not generate the other.

[0027] The first laser beam LB1 mainly causes linear absorption by irradiating the glass plate 10. That the main occurrence is linear absorption means that the amount of heat generated by linear absorption is larger than the amount of heat generated by non-linear absorption. Non-linear absorption may hardly occur. The heat generated by the first laser beam LB1 forms the first crack CR1 and the second crack CR2.

[0028] Non-linear absorption is also called multi-photon absorption. The probability of multi-photon absorption occurring is non-linear with respect to the photon density (the power density of the first laser beam LB1), and the higher the photon density, the more dramatically the probability increases. For example, the probability of two-photon absorption occurring is proportional to the square of the photon density. At any position of the glass plate 10, the photon density may be less than 1×10 8 W / cm 2 . In this case, non-linear absorption hardly occurs.

[0029] On the other hand, linear absorption is also called one-photon absorption. The probability of one-photon absorption occurring is proportional to the photon density. In the case of one-photon absorption, according to Lambert-Beer’s law, the following formula (1) holds. I = I 0 × exp(-α × L) ··· (1) In the above formula (1), I0 is the intensity of the first laser beam LB1 on the first main surface 11, I is the intensity of the first laser beam LB1 on the second main surface 12, L is the propagation distance of the first laser beam LB1 from the first main surface 11 to the second main surface 12, and α is the absorption coefficient of the glass with respect to the first laser beam LB1. α is the absorption coefficient of linear absorption and is determined by the wavelength of the first laser beam LB1, the chemical composition of the glass, etc.

[0030] α×L represents the internal transmittance. The internal transmittance is the transmittance when it is assumed that the first laser beam LB1 is not reflected by the first main surface 11. The smaller α×L is, the larger the internal transmittance is. α×L is, for example, 3.0 or less, more preferably 2.3 or less, and still more preferably 1.6 or less. In other words, the internal transmittance is, for example, 5% or more, preferably 10% or more, and more preferably 20% or more. If α×L is 3.0 or less, the internal transmittance is 5% or more, and both the first main surface 11 and the second main surface 12 are sufficiently heated.

[0031] From the viewpoint of heating efficiency, α×L is preferably 0.002 or more, more preferably 0.01 or more, and still more preferably 0.02 or more. In other words, the internal transmittance is preferably 99.8% or less, more preferably 99% or less, and still more preferably 98% or less.

[0032] If the temperature of the glass exceeds the annealing point, plastic deformation of the glass tends to progress, and the generation of thermal stress is restricted. Therefore, the light wavelength, output, beam diameter at the first main surface 11, etc. are adjusted so that the temperature of the glass becomes equal to or lower than the annealing temperature.

[0033] The first laser beam LB1 is, for example, continuous wave light. The light source of the first laser beam LB1 is not particularly limited, but is, for example, a Yb fiber laser. The Yb fiber laser is one in which Yb is doped into the core of an optical fiber and outputs continuous wave light with a wavelength of 1070 nm.

[0034] However, the first laser beam LB1 may be pulsed light instead of continuous wave light.

[0035] The first laser beam LB1 is irradiated onto the first main surface 11 by an optical system including a condenser lens or the like. By moving the irradiation point along the first separation line BL1, the first crack CR1 is formed over the entire first separation line BL1. At this time, the second crack CR2 is formed over the entire second separation line BL2.

[0036] For the movement of the irradiation point, for example, a 2D galvanometer scanner or a 3D galvanometer scanner is used. Note that the movement of the irradiation point may also be carried out by the movement or rotation of the stage that holds the glass plate 10. As the stage, for example, an XY stage, an XYθ stage, an XYZ stage, or an XYZθ stage is used. The X-axis, Y-axis, and Z-axis are orthogonal to each other, the X-axis and Y-axis are parallel to the first main surface 11, and the Z-axis is perpendicular to the first main surface 11.

[0037] Next, in S3 of FIG. 1, as shown in FIG. 2C, the irradiation point of the second laser beam LB2 is moved along the first separation line BL1 to form the modified portion D. The modified portion D is formed on the virtual line VL in the cross section orthogonal to the first separation line BL1. The virtual line VL extends in a direction perpendicular to the first main surface 11 from the tip of the first crack CR1 toward the center of the plate thickness. The virtual line VL extends in a direction perpendicular to the first main surface 11 from the tip of the first crack CR1 to the tip of the second crack CR2.

[0038] The second laser beam LB2 is pulsed light and forms the modified portion D by non-linear absorption. It is preferable to use pulsed laser light with a wavelength range of 250 nm to 3000 nm and a pulse width of 10 fs to 1000 ns. Since the laser light with a wavelength range of 250 nm to 3000 nm penetrates the glass plate 10 to some extent, non-linear absorption can occur inside the glass plate 10 to form the modified portion D. The wavelength range is preferably 260 nm to 2500 nm. Also, if it is pulsed laser light with a pulse width of 1000 ns or less, it is easy to increase the photon density, and non-linear absorption can occur inside the glass plate 10 to form the modified portion D. The pulse width is preferably 100 fs to 100 ns. Note that the second laser beam LB2 may be pulsed light that simultaneously forms a plurality of focus points in the optical axis direction by a multi-focus optical system.

[0039] The modified portion D has a changed glass density or refractive index. The modified portion D is a void or a modified layer, etc. The modified layer is a layer with a changed density or refractive index due to a structural change or due to melting and re-solidification.

[0040] The second laser beam LB2 is linearly focused inside, for example, the glass plate 10 to linearly form the modification part D. The light source of the second laser beam LB2 may output a pulse train called a burst. One pulse train has a plurality (for example, 3 to 50) of pulsed lights, and each pulsed light has a pulse width of less than 10 nanoseconds. In one pulse train, the energy of the pulsed light may gradually decrease.

[0041] The pulsed light may be linearly focused by self-focusing due to the non-linear Kerr effect. The pulsed light may also be linearly focused in the optical axis direction by an optical system. As a specific optical system, for example, an axicon lens is used.

[0042] The pulsed light generates the modification part D. The modification part D is formed throughout the entire thickness direction from the first main surface 11 to the second main surface 12. As will be described again later, the modification part D may be formed only in a part of the thickness direction, for example, only on the first main surface 11 side with reference to the center of the plate thickness.

[0043] The light source of the second laser beam LB2 may include, for example, a YAG crystal doped with Nd (Nd:YAG) and output pulsed light with a wavelength of 1064 nm. The wavelength of the pulsed light is not limited to 1064 nm. An Nd;YAG second harmonic laser (wavelength 532 nm), an Nd;YAG third harmonic laser (wavelength 355 nm), etc. can also be used.

[0044] The second laser beam LB2 is irradiated onto the first main surface 11 by an optical system including a condenser lens or the like. By moving the irradiation point along the first separation line BL1, the modification part D is formed throughout the entire first separation line BL1. At this time, the modification part D is formed along the entire second separation line BL2.

[0045] For the movement of the irradiation point, for example, a 2D galvanometer scanner or a 3D galvanometer scanner is used. Note that the movement of the irradiation point may also be performed by moving or rotating the stage that holds the glass plate 10. As the stage, for example, an XY stage, an XYθ stage, an XYZ stage, or an XYZθ stage is used.

[0046] Next, in S4 of FIG. 1, as shown in FIG. 2D, stress is applied to the glass plate 10 to form a third crack CR3 that spans the tip of the first crack CR1 and the modified portion D. The third crack CR3 spans the tip of the first crack CR1 and the tip of the second crack CR2.

[0047] In the formation of the third crack CR3, for example, again, the irradiation point of the first laser beam LB1 is moved along the first separation line BL1 to apply thermal stress to the glass plate 10. Note that while pressing a roller against the glass plate 10, it may be moved along the first separation line BL1 to apply stress to the glass plate 10.

[0048] According to the first example, before the formation of the third crack CR3, the modified portion D is formed on the virtual line VL. The virtual line VL extends perpendicular to the first main surface 11 and the second main surface 12, unlike the extension lines of the first crack CR1 and the second crack CR2. The modified portion D guides the third crack CR3 to the virtual line VL. Therefore, the third crack CR3 can be generated from the tips of the first crack CR1 and the second crack CR2 in a direction perpendicular to the first main surface 11 and the second main surface 12.

[0049] After S4 in FIG. 1, the glass plate 10 shown in FIG. 2E is obtained. The glass plate 10 has a first main surface 11, a second main surface 12, a first inclined surface 13, a second inclined surface 14, and an end surface 15. The second main surface 12 faces the opposite direction to the first main surface 11.

[0050] The first inclined surface 13 corresponds to a so-called chamfered surface and intersects the first main surface 11 at an obtuse angle in a cross-section perpendicular to the periphery of the first main surface 11. The inner angle between the first inclined surface 13 and the first main surface 11 is an obtuse angle. The outer angle θ1 between the first inclined surface 13 and the first main surface 11 is, for example, 20° to 80°, preferably 30° to 60°.

[0051] On the other hand, the second inclined surface 14 intersects the second main surface 12 at an obtuse angle in a cross-section perpendicular to the periphery of the second main surface 12. The internal angle between the second inclined surface 14 and the second main surface 12 is an obtuse angle. The external angle θ2 between the second inclined surface 14 and the second main surface 12 is, for example, 20° to 80°, preferably 30° to 60°.

[0052] The first inclined surface 13 is formed by the first crack CR1. The first crack CR1 extends in its moving direction as the irradiation point of the first laser beam LB1 moves. Therefore, the first inclined surface 13 includes Wallner lines or Arrest Lines. The "Wallner lines" are striped lines indicating the extension direction of cracks. The "Arrest Lines" are striped lines indicating a temporary stop of crack extension. Note that the second inclined surface 14 also includes Wallner lines or Arrest Lines, similar to the first inclined surface 13.

[0053] The arithmetic mean roughness Ra of the first inclined surface 13 is, from the viewpoint of improving the fracture strength of the glass plate 10, less than 0.1 μm, preferably 50 nm or less, and more preferably 10 nm or less. The arithmetic mean roughness Ra of the first inclined surface 13 is, for example, 1 nm or more, preferably 2 nm or more. The arithmetic mean roughness Ra is measured in accordance with Japanese Industrial Standard JIS B0601:2013. The arithmetic mean roughness Ra of the second inclined surface 14 is the same as that of the first inclined surface 13. If the arithmetic mean roughness Ra of the first inclined surface 13 and / or the arithmetic mean roughness Ra of the second inclined surface 14 of the glass plate 10 is within the above range, the fracture strength of the glass plate 10 is improved, which is particularly preferable when the glass plate 10 is used as an automotive window glass or a cover glass for automotive interior parts.

[0054] The end surface 15 extends in a direction perpendicular to the first main surface 11 from the respective tips of the first inclined surface 13 and the second inclined surface 14. Here, the "direction perpendicular to the first main surface 11" means a direction in which the angle formed with the normal line of the first main surface 11 is 10° or less.

[0055] The end face 15 is generated by the third crack CR3 and coincides with the virtual line VL. The virtual line VL is a straight line in a cross section orthogonal to the periphery of the first main surface 11, but may be a rounded curve as will be described later.

[0056] Since the end face 15 includes the modified portion D formed on the virtual line VL, it has an arithmetic mean roughness Ra larger than those of the first inclined surface 13 and the second inclined surface 14. The arithmetic mean roughness Ra of the end face 15 is, for example, 0.1 μm or more, preferably 0.2 μm or more. When the arithmetic mean roughness Ra of the end face 15 is 0.1 μm or more, slippage can be suppressed when gripping the end face 15. The arithmetic mean roughness Ra of the end face 15 is, for example, 5 μm or less, preferably 3 μm or less.

[0057] Next, with reference to FIGS. 3A and 3B, a second example of S3 and S4 in FIG. 1 will be described. Note that since the glass plate 10 obtained after S4 in the second example is the same as the glass plate 10 obtained after S4 in the first example, illustration thereof is omitted. Hereinafter, differences from the first example will be mainly described.

[0058] In S3 of FIG. 1, as shown in FIG. 3A, the second laser beam LB2 may be focused in a dot shape inside the glass plate 10 to form the modified portion D in a dot shape. The light source of the second laser beam LB2 outputs single pulse light or a pulse train.

[0059] The light wavelength, pulse width, etc. are adjusted so that multiphoton absorption occurs only in the vicinity of the focal point.

[0060] The light source of the second laser beam LB2 may include, for example, a YAG crystal doped with Nd (Nd:YAG) and output pulse light with a wavelength of 1064 nm. Note that the wavelength of the pulse light is not limited to 1064 nm. An Nd;YAG second harmonic laser (wavelength 532 nm), an Nd;YAG third harmonic laser (wavelength 355 nm), etc. can also be used.

[0061] The second laser beam LB2 is focused into a dot by an optical system including a condenser lens or the like. The modification part D is repeatedly and dispersedly arranged by two-dimensionally moving the focus point within a plane having a constant depth from the first main surface 11 and changing the depth of the focus point from the first main surface 11. For the movement of the focus point, for example, a 3D galvanometer scanner is used. When the depth of the focus point is changed by the movement of the stage, a 2D galvanometer scanner may be used.

[0062] The stage holds the glass plate 10. The movement of the focus point may be performed by the movement or rotation of the stage that holds the glass plate 10. As the stage, for example, an XY stage, an XYθ stage, an XYZ stage, or an XYZθ stage is used. The X-axis, Y-axis, and Z-axis are orthogonal to each other, the X-axis and Y-axis are parallel to the first main surface 11, and the Z-axis is perpendicular to the first main surface 11.

[0063] The modification part D is formed across the entire thickness direction from the tip of the first crack CR1 to the tip of the second crack CR2. Incidentally, although it will be described again later, the modification part D may be formed only in a part of the thickness direction, for example, only on the first main surface 11 side with reference to the center of the thickness.

[0064] Next, in S4 of FIG. 1, as shown in FIG. 3B, stress is applied to the glass plate 10 to form a third crack CR3 that extends from the tip of the first crack CR1 to the modification part D. The third crack CR3 extends from the tip of the first crack CR1 to the tip of the second crack CR2.

[0065] According to the second example, similar to the first example, before the formation of the third crack CR3, the modification part D is formed on the virtual line VL. The modification part D guides the third crack CR3 to the virtual line VL. Therefore, the third crack CR3 can be generated in a direction perpendicular to the first main surface 11 and the second main surface 12 from the tips of the first crack CR1 and the second crack CR2.

[0066] Next, with reference to FIGS. 4A and 4B, a third example of S3 and S4 in FIG. 1 will be described. Hereinafter, the differences from the first example and the second example will be mainly described.

[0067] In S3 of FIG. 1, as shown in FIG. 4A, the virtual line VL is a rounded curve. It is sufficient that the angle formed by the tangent of the curve and the normal of the first main surface 11 is 10° or less. A plurality of modification portions D are arranged on the virtual line VL.

[0068] Next, in S4 of FIG. 1, as shown in FIG. 4B, stress is applied to the glass plate 10 to form a third crack CR3 that extends from the tip of the first crack CR1 and spans the modification portion D. The third crack CR3 extends from the tip of the first crack CR1 to the tip of the second crack CR2.

[0069] According to the third example, similar to the first example, before the formation of the third crack CR3, the modification portion D is formed on the virtual line VL. The modification portion D guides the third crack CR3 to the virtual line VL. Therefore, the third crack CR3 can be generated from the tips of the first crack CR1 and the second crack CR2 in a direction perpendicular to the first main surface 11 and the second main surface 12.

[0070] (Second Embodiment) By the way, as shown in FIG. 5, the glass plate processing method may further include S5 in addition to S1 to S4. Hereinafter, with reference to FIGS. 6A to 6E, S3 to S5 of FIG. 5 will be described. Note that S1 to S2 in FIG. 5 are the same as S1 to S2 in FIG. 1, so the description thereof will be omitted.

[0071] First, in S3 of FIG. 5, as shown in FIG. 6A, the second laser beam LB2 is focused in a dot shape inside the glass plate 10 to form the modification portion D in a dot shape. The modification portion D is formed only on the first main surface 11 side with reference to the center of the plate thickness of the glass plate 10.

[0072] Next, in S4 of FIG. 5, as shown in FIG. 6B, stress is applied to the glass plate 10 to form a third crack CR3 that extends from the tip of the first crack CR1 and spans the modification portion D. The third crack CR3 extends from the tip of the first crack CR1 to the tip of the second crack CR2.

[0073] After S4 in FIG. 5, a glass plate 10 shown in FIG. 6C is obtained. The glass plate 10 has a first main surface 11, a second main surface 12, a first inclined surface 13, a second inclined surface 14, and an end surface 15. The end surface 15 is divided, from the viewpoint of surface roughness Ra, with reference to the center of the plate thickness, into a first end surface portion 151 on the first main surface 11 side and a second end surface portion 152 on the second main surface 12 side.

[0074] The first end surface portion 151 includes a modified portion D. Therefore, the arithmetic mean roughness Ra of the first end surface portion 151 is, for example, 0.1 μm or more, preferably 0.2 μm or more. The arithmetic mean roughness Ra of the first end surface portion 151 is, for example, 5 μm or less, preferably 3 μm or less.

[0075] On the other hand, the second end surface portion 152 does not include the modified portion D. Therefore, the arithmetic mean roughness Ra of the second end surface portion 152 is, for example, less than 0.1 μm, preferably 50 nm or less, more preferably 10 nm or less. The arithmetic mean roughness Ra of the second end surface portion 152 is, for example, 1 nm or more, preferably 2 nm or more.

[0076] Next, in S5 of FIG. 5, as shown in FIG. 6D, the first inclined surface 13 is ground with a grinding wheel 20. The first inclined surface 13 can be roughened. The grinding wheel 20 is a truncated cone symmetric about a rotation axis 21, and moves along the periphery of the first main surface 11 while rotating about the rotation axis 21.

[0077] The average particle diameter D50 of the abrasive grains of the grinding wheel 20 is, for example, 20 μm to 40 μm, preferably 10 μm to 20 μm. D50 is the particle diameter corresponding to 50% of the cumulative number in the particle size distribution. The particle size distribution is measured with a laser diffraction particle size analyzer.

[0078] After S5 in FIG. 5, a glass plate 10 shown in FIG. 6E is obtained. The glass plate 10 has a first main surface 11, a second main surface 12, a first inclined surface 13, a second inclined surface 14, and an end surface 15. The end surface 15 includes a first end surface portion 151 on the first main surface 11 side and a second end surface portion 152 on the second main surface 12 side with reference to the center of the plate thickness.

[0079] The first inclined surface 13 is roughened with a grinding stone 20. Therefore, the arithmetic mean roughness Ra of the first inclined surface 13 is, for example, 0.1 μm or more, preferably 0.2 μm or more. The arithmetic mean roughness Ra of the first inclined surface 13 is, for example, 5 μm or less, preferably 3 μm or less.

[0080] On the other hand, the second inclined surface 14 is not roughened with the grinding stone 20. Therefore, the arithmetic mean roughness Ra of the second inclined surface 14 is, for example, less than 0.1 μm, preferably 50 nm or less, and more preferably 10 nm or less. The arithmetic mean roughness Ra of the second inclined surface 14 is, for example, 1 nm or more, preferably 2 nm or more.

[0081] The side surface of the glass plate 10 shown in FIG. 6E is divided into a rough surface 101 with a surface roughness Ra of 0.1 μm or more and a mirror surface 102 with a surface roughness Ra of less than 0.1 μm with reference to the center of the plate thickness. The rough surface 101 includes the first inclined surface 13 and the first end surface portion 151 following the first inclined surface 13. On the other hand, the mirror surface 102 includes the second inclined surface 14 and the second end surface portion 152 following the second inclined surface 14. As described above, the first inclined surface 13 is roughened with the grinding stone 20.

[0082] The first inclined surface 13 is obtained by forming the first crack CR1 in S2 of FIG. 5 and further grinding in S5 of FIG. 5, but it may be obtained by another method. For example, in S2 of FIG. 5, only the second crack CR2 may be formed without forming the first crack CR1. In this case, the first inclined surface 13 is obtained by grinding the perpendicular angle between the first main surface 11 and the first end surface portion 151 with a grinding stone in S5 of FIG. 5.

[0083] The first end surface portion 151 is not ground in S5 of FIG. 5, but it may be ground in S5 of FIG. 5. In the latter case, a step may be formed between the first end surface portion 151 and the second end surface portion 152.

[0084] The glass plate 10 shown in FIG. 6E is suitably used as a cover glass for an in-vehicle display. The glass plate 10 is installed inside the vehicle with the first main surface 11 facing the vehicle occupants. An antireflection film is formed in advance on the first main surface 11 and the first inclined surface 13.

[0085] The antireflection film suppresses light reflection and is, for example, a laminate of a high refractive index layer and a low refractive index layer having a lower refractive index than the high refractive index layer, laminated alternately. The material of the high refractive index layer is, for example, niobium oxide, titanium oxide, zirconium oxide, tantalum oxide, or silicon nitride. On the other hand, the material of the low refractive index layer is, for example, silicon oxide, a mixed oxide of Si and Sn, a mixed oxide of Si and Zr, or a mixed oxide of Si and Al.

[0086] When a vehicle occupant collides with the first main surface 11, a compressive stress acts on the first main surface 11 side and a tensile stress acts on the second main surface 12 side with reference to the center of the plate thickness of the glass plate 10. Therefore, a compressive stress acts on the rough surface 101 and a tensile stress acts on the mirror surface 102 among the side surfaces of the glass plate 10.

[0087] According to the present embodiment, since the tensile stress acts on the mirror surface 102, the strength is higher than when the tensile stress acts on the rough surface 101. This is because the mirror surface 102 has fewer irregularities serving as fracture initiation points than the rough surface 101. Generally, since a material is fractured by tensile stress rather than compressive stress, even if a compressive stress acts on the rough surface 101, it does not pose a problem.

[0088] Also, according to the present embodiment, the first inclined surface 13 is the rough surface 101. Therefore, it is possible to suppress the antireflection film on the first inclined surface 13 from appearing iridescent due to light interference as compared with the case where the first inclined surface 13 is the mirror surface 102.

[0089] (Third Embodiment) Incidentally, as shown in FIG. 7, the method for processing the glass plate may further include S6 in addition to S1 to S4. Note that the timing at which S6 is performed is not limited to the timing shown in FIG. 7, and may be, for example, between S1 and S2, or between S2 and S3. Hereinafter, with reference to FIGS. 9A to 9I, S2 to S4 and S6 in FIG. 7 will be described. Note that S1 in FIG. 7 is the same as S1 in FIG. 1, so the description thereof will be omitted. Note that after S4 in FIG. 7, S5 in FIG. 5 may be performed.

[0090] First, in S2 of FIG. 7, as shown in FIG. 9B, the irradiation point of the first laser beam LB1 is moved along the first separation line BL1 to form the first crack CR1 and the second crack CR2.

[0091] As shown in FIG. 9A, the first separation line BL1 has a curved portion BL1a in a plan view. Similarly, the second separation line BL2 also has a curved portion BL2a like the first separation line BL1.

[0092] As shown in FIG. 9B, in a cross section orthogonal to the first separation line BL1, the first crack CR1 inclines toward the center of curvature C of the curved portion BL1a as the depth from the first main surface 11 increases. Similarly, in a cross section orthogonal to the second separation line BL2, the second crack CR2 inclines toward the center of curvature C as the depth from the second main surface 12 increases.

[0093] Next, in S3 of FIG. 7, as shown in FIG. 9C, the second laser beam LB2 is focused in a dot shape inside the glass plate 10 to form a modified portion D in a dot shape. The modified portions D are arranged on a linear virtual line VL as in the second example shown in FIG. 3A, but may be arranged on a curved virtual line VL as in the third example shown in FIG. 4A.

[0094] Note that in S3 of FIG. 7, as described above, the second laser beam LB2 is focused in a dot shape inside the glass plate 10 to form the modified portion D in a dot shape. However, as in the first example shown in FIG. 2C, the second laser beam LB2 may be focused in a line shape to form the modified portion D in a line shape.

[0095] Next, in S6 of FIG. 7, a part of the glass plate 10, for example, a part including the curvature center C of the curved portion BL1a of the first separation line BL1, is extracted on the extraction plane 17 shown in FIG. 9A. The extraction plane 17 is set between the first separation line BL1 and its curvature center C.

[0096] As shown in FIG. 9B, the extraction plane 17 has a first intersection line 18 that intersects the first main surface 11 and a second intersection line 19 that intersects the second main surface 12. The first intersection line 18 has a curved portion with the same curvature center C as the first separation line BL1. The first intersection line 18 only needs to have a curved portion and may further have a straight portion. Similarly, the second intersection line 19 also has a curved portion.

[0097] As shown in FIG. 9A, in a plan view, the first intersection line 18 is disposed on one side of the second intersection line 19. Specifically, for example, the first intersection line 18 is disposed on the curvature center C side with respect to the second intersection line 19. Note that the arrangements of the first intersection line 18 and the second intersection line 19 may be reversed, and the first intersection line 18 may be disposed on the side opposite to the curvature center C with respect to the second intersection line 19.

[0098] As shown in FIG. 9B, in a cross section orthogonal to the first intersection line 18, the extraction plane 17 is inclined with respect to the normal line N of the first main surface 11. The extraction plane 17 is, for example, a linear taper. The angle β formed by the normal line N of the first main surface 11 and the extraction plane 17 is, for example, 3° or more. If β is 3° or more, as will be described in detail later, as shown in FIG. 9F, a part of the glass plate 10 can be extracted in the normal line direction of the first main surface 11. β is, for example, 45° or less.

[0099] Note that the extraction plane 17 is a linear taper in the present embodiment, but it may be a non-linear taper. In this case, β is the angle formed by the normal line N of the first main surface 11 and the tangent line of the extraction plane 17. It is sufficient that β is within the above range.

[0100] S6 in FIG. 7 includes S61 to S63 shown in FIG. 8. First, in S61 of FIG. 8, as shown in FIG. 9D, the second laser beam LB2 is focused in a dot shape inside the glass plate 10, and a dot-shaped modified portion D is formed at the focus point.

[0101] The modification part D repeatedly performs two-dimensional movement of the condensing point within a plane with a constant depth from the first main surface 11 and changes the depth of the condensing point from the first main surface 11, and is dispersedly arranged on the extraction surface 17. For the movement of the condensing point, for example, a 3D galvanometer scanner is used. When the change in the depth of the condensing point is performed by the movement of the stage, a 2D galvanometer scanner may be used.

[0102] The stage holds the glass plate 10. The movement of the condensing point may be carried out by the movement or rotation of the stage that holds the glass plate 10. As the stage, for example, an XY stage, an XYθ stage, an XYZ stage, or an XYZθ stage is used.

[0103] The modification part D is formed throughout the entire thickness direction from the first main surface 11 to the second main surface 12. Here, the entire thickness direction means a region of 80% or more of the plate thickness. In S62 described later, the fourth crack CR4 can be formed throughout the entire thickness direction.

[0104] Next, in S62 of FIG. 8, as shown in FIG. 9E, stress is applied to the glass plate 10 to form the fourth crack CR4 on the extraction surface 17. The fourth crack CR4 is formed starting from the modification part D and is formed from the first main surface 11 to the second main surface 12.

[0105] In the formation of the fourth crack CR4, for example, thermal stress is applied to the glass plate 10 by irradiating the first laser beam LB1. Note that the method of applying stress to the glass plate 10 is not particularly limited. A roller may be pressed against the glass plate 10 to apply stress to the glass plate 10.

[0106] Finally, in S63 of FIG. 8, as shown in FIG. 9F, a part of the glass plate 10, for example, a part including the curvature center C, is extracted. In the extraction, a part of the glass plate 10 and the remaining part are displaced in the normal direction of the first main surface 11. A part of the glass plate 10 can be extracted without crushing both the part of the glass plate 10 and the remaining part.

[0107] Before shifting a part and the remaining part of the glass plate 10 in the normal direction of the first main surface 11, a temperature difference may be applied between the part and the remaining part of the glass plate 10 to form a gap between the part and the remaining part of the glass plate 10. Rubbing between glasses can be suppressed.

[0108] Based on the first intersection line 18, if the portion on the curvature center C side is at a lower temperature than the portion on the side opposite to the curvature center C, a gap is formed. The portion on the curvature center C side may be cooled, or the portion on the side opposite to the curvature center C may be heated.

[0109] The remaining part of the glass plate 10 is a part including the first crack CR1 and the second crack CR2. By extracting a part of the glass plate 10, the deformation of the remaining part of the glass plate 10 becomes easy, and subsequent processing becomes easy.

[0110] Next, in S4 of FIG. 7, as shown in FIG. 9G, stress is applied to the glass plate 10 to form a third crack CR3 that extends from the tip of the first crack CR1 to the modified portion D. The third crack CR3 extends from the tip of the first crack CR1 to the tip of the second crack CR2.

[0111] According to the present embodiment, similar to the first embodiment and the second embodiment, before the formation of the third crack CR3, the modified portion D is formed on the virtual line VL. The modified portion D guides the third crack CR3 to the virtual line VL. Therefore, the third crack CR3 can be generated in a direction perpendicular to the first main surface 11 and the second main surface 12 from the tips of the first crack CR1 and the second crack CR2.

[0112] Also, according to the present embodiment, as shown in FIG. 9A, the first separation line BL1 has a curved portion BL1a in plan view, and a plurality of modified portions D are arranged along the curved portion BL1a. The third crack CR3 can be induced in the arrangement direction.

[0113] Also, according to the present embodiment, as shown in FIG. 9B, in a cross-section orthogonal to the first separation line BL1, the first crack CR1 inclines toward the curvature center C side of the curved portion BL1a as the depth from the first main surface 11 increases. Based on the curved portion BL1a, the portion on the side opposite to the curvature center C (the portion on the left side of the curved portion BL1a in FIG. 9A) becomes the product.

[0114] When the portion on the side opposite to the curvature center C with respect to the curved portion BL1a becomes the product, it is of great technical significance to arrange a plurality of modified portions D on the curved portion BL1a and induce a third crack CR3 in the arrangement direction. This is because if the third crack CR3 extends straight in the tangent direction at a specific point of the curved portion BL1a, the product will be damaged.

[0115] The radius of curvature of the curved portion BL1a is, for example, 0.5 mm or more, preferably 1 mm or more, so that the third crack CR3 is likely to bend along the curved portion BL1a. Also, the radius of curvature of the curved portion BL1a is, for example, 1000 mm or less, preferably 500 mm or less.

[0116] After S4 in FIG. 7, unnecessary portions from the third crack CR3 to the fourth crack CR4 shown in FIG. 9G are removed. For example, laser light is irradiated onto the unnecessary portions, and the unnecessary portions are crushed into a plurality of fragments by heat and removed. As a result, the glass plate 10 shown in FIGS. 9H and 9I is obtained. The glass plate 10 has a first main surface 11, a second main surface 12, a first inclined surface 13, a second inclined surface 14, and an end surface 15. Note that the removal of the unnecessary portions can also be realized by cooling shrinkage instead of heat crushing.

Example

[0117] Hereinafter, a specific example of the method for processing a glass plate will be described.

[0118] 〔Example 1〕 In Example 1, S1 to S4 in FIG. 1 were implemented. In S1, as the glass plate 10, soda lime glass with a thickness of 1.8 mm was prepared. The first main surface 11 was a rectangle with a length of 100 mm and a width of 50 mm. The first separation line BL1 was a straight line extending diagonally from one long side of the first main surface 11 to the other long side.

[0119] In S2, as shown in FIG. 2B, the irradiation point of the first laser beam LB1 was moved along the first separation line BL1 to form the first crack CR1 and the second crack CR2. A 3D galvanometer scanner was used for the movement of the irradiation point.

[0120] The irradiation conditions of the first laser beam LB1 in S2 were as follows. Oscillator: Yb fiber laser (manufactured by IPG Photonics, YLR500) Oscillation mode: Continuous wave oscillation Light wavelength: 1070 nm Output: 440 W Scanning speed in the in-plane direction: 70 mm / s Beam diameter on the first main surface 11: 0.6 mm.

[0121] In S3, as shown in FIG. 2C, the second laser beam LB2 was linearly focused inside the glass plate 10 to linearly form the modified portion D. The irradiation point of the second laser beam LB2 was moved along the first separation line BL1, and a plurality of modified portions D were formed at a predetermined pitch along the first separation line BL1. An XYZ stage was used for the movement of the irradiation point.

[0122] The irradiation conditions of the second laser beam LB2 in S3 were as follows. Oscillator: Picosecond pulse laser (manufactured by Rofin, StarPico3) Oscillation mode: Pulse oscillation (burst) Light wavelength: 1064 nm Output: 35.6 W Oscillation frequency: 75 kHz Scanning speed in the in-plane direction: 187.5 mm / s Irradiation pitch in the in-plane direction: 5 μm Pulse energy: 475 μJ.

[0123] In S4, as shown in FIG. 2D, stress was applied to the glass plate 10 to form a third crack CR3 spanning the tip of the first crack CR1 and the tip of the second crack CR2. In forming the third crack CR3, thermal stress was applied to the glass plate 10 by irradiating the first laser beam LB1. For the movement of the irradiation point of the first laser beam LB1, an XYZ stage was used. The irradiation conditions of the first laser beam LB1 in S4 were the same as those in S2.

[0124] After S4, the glass plate 10 shown in FIG. 2E was obtained. The arithmetic mean roughness Ra of the first inclined surface 13, the second inclined surface 14, and the end surface 15 of the glass plate 10 was measured using a surface roughness measuring instrument (DektakXT manufactured by Bruker). The measurement conditions are shown below. Cut-off value λc: 0.025 mm Cut-off ratio λc / λs: 10 Measurement speed: 0.1 mm / sec Evaluation length: 1.0 mm.

[0125] The arithmetic mean roughness Ra of the first inclined surface 13 was 5.2 nm. Also, the arithmetic mean roughness Ra of the second inclined surface 14 was also 5.2 nm. On the other hand, the arithmetic mean roughness Ra of the end surface 15 was 0.4 μm.

[0126] 〔Example 2〕 In Example 2, S1 to S5 in FIG. 5 were carried out. In S1, as the glass plate 10, aluminosilicate glass with a thickness of 1.3 mm was prepared. The first main surface 11 was a rectangle with a length of 100 mm and a width of 50 mm. The first separation line BL1 was a straight line extending from the long side of the first main surface 11 in an oblique direction to the other long side.

[0127] In S2, as shown in FIG. 2B, the irradiation point of the first laser beam LB1 was moved along the first separation line BL1 to form the first crack CR1 and the second crack CR2. For the movement of the irradiation point, a 3D galvanometer scanner was used.

[0128] The irradiation conditions of the first laser beam LB1 in S2 were as follows. Oscillator: Yb fiber laser (manufactured by IPG Photonics, YLR500) Oscillation mode: Continuous wave oscillation Light wavelength: 1070 nm Output: 440 W Scanning speed in the in-plane direction: 70 mm / s Beam diameter at the first principal plane 11: 0.6 mm

[0129] In S3, as shown in Fig. 6A, the second laser beam LB2 was focused into a dot inside the glass plate 10, and the modified portion D was formed in a dot shape. The modified portion D was formed only on the first principal plane 11 side with reference to the center of the plate thickness of the glass plate 10. For the movement of the focus point, an XYZ stage was used.

[0130] The irradiation conditions of the second laser beam LB2 in S3 were as follows. Oscillator: Nanosecond pulsed laser (manufactured by Spectra-Physics, Explorer532-2Y) Oscillation mode: Pulsed oscillation (single) Light wavelength: 532 nm Output: 2 W Oscillation frequency: 10 kHz Scanning speed in the in-plane direction: 100 mm / s Irradiation pitch in the in-plane direction: 0.01 mm Irradiation pitch in the depth direction: 0.05 mm Focused beam diameter: 4 μm Pulse energy: 200 μJ

[0131] In S4, as shown in Fig. 6B, stress was applied to the glass plate 10 to form a third crack CR3 that spanned the tip of the first crack CR1 and the tip of the second crack CR2. In the formation of the third crack CR3, thermal stress was applied to the glass plate 10 by the irradiation of the first laser beam LB1. For the movement of the irradiation point of the first laser beam LB1, an XYZ stage was used. The irradiation conditions of the first laser beam LB1 in S4 were the same as those of the first laser beam LB1 in S2.

[0132] In S5, as shown in FIG. 6D, the first inclined surface 13 was ground and roughened with a grinding wheel 20. The average particle size D50 of the abrasive grains of the grinding wheel 20 was 40 μm.

[0133] After S5, the glass plate 10 shown in FIG. 6E was obtained. The arithmetic mean roughness Ra of the first inclined surface 13 was 0.5 μm. The arithmetic mean roughness Ra of the first end surface portion 151 of the end surface 15 was 2.1 μm. On the other hand, the arithmetic mean roughness Ra of the second end surface portion 152 of the end surface 15 was 2.9 nm. The arithmetic mean roughness Ra of the second inclined surface 14 was 5.2 nm.

[0134] As the glass plate 10 shown in FIG. 6E, a specimen for a four-point bending test was fabricated and a four-point bending test was performed. In the four-point bending test, a compressive stress was generated on the first main surface 11 and a tensile stress was generated on the second main surface 12. As a result, the fracture strength was 248 MPa. Also, it was confirmed that the origin of fracture was the second main surface 12, not the second inclined surface 14 and the second end surface portion 152.

[0135] 〔Example 3〕 In Example 3, S1 to S4 and S6 in FIG. 7 were carried out. In S1, as the glass plate 10, a soda-lime glass with a thickness of 3.5 mm was prepared. The first main surface 11 was a rectangle with a length of 200 mm and a width of 150 mm. The curved portion BL1a of the first separation line BL1 was an arc with a radius of 80 mm. The angle β formed by the normal line of the first main surface 11 and the extraction surface 17 was 4°.

[0136] In S2, as shown in FIGS. 9A and 9B, the irradiation point of the first laser beam LB1 was moved along the first separation line BL1 to form the first crack CR1 and the second crack CR2. An XYZ stage was used for the movement of the irradiation point.

[0137] The irradiation conditions of the first laser beam LB1 in S2 were as follows. Oscillator: Yb fiber laser (manufactured by IPG Photonics, YLR500) Oscillation mode: continuous wave oscillation Light wavelength: 1070 nm Output: 220 W In-plane scanning speed: 70 mm / s Beam diameter on the first major surface 11: 1.2 mm.

[0138] In S3, as shown in FIG. 9C, the second laser beam LB2 was focused into a dot inside the glass plate 10, and the modified portion D was formed in a dot shape. The modified portion D was repeatedly formed by two-dimensional movement of the focusing point in a plane with a constant depth from the first major surface 11 and by changing the depth of the focusing point from the first major surface 11, and was dispersedly arranged on the extraction surface 17. For the movement of the focusing point, an XYZ stage was used.

[0139] The irradiation conditions of the second laser beam LB2 in S3 were as follows. Oscillator: Nanosecond pulse laser (manufactured by Spectra-Physics, Explorer532-2Y) Oscillation mode: Pulse oscillation (single) Light wavelength: 532 nm Output: 2 W Oscillation frequency: 10 kHz In-plane scanning speed: 100 mm / s In-plane irradiation pitch: 0.01 mm Depth-direction irradiation pitch: 0.05 mm Focused beam diameter: 4 μm Pulse energy: 200 μJ.

[0140] In S61 included in S6, as shown in FIG. 9D, the second laser beam LB2 was focused into a dot inside the glass plate 10, and a dot-shaped modified portion D was formed at the focusing point. The modified portion D was repeatedly formed by two-dimensional movement of the focusing point in a plane with a constant depth from the first major surface 11 and by changing the depth of the focusing point from the first major surface 11, and was dispersedly arranged on the extraction surface 17. For the movement of the focusing point, an XYZ stage was used. The irradiation conditions of the second laser beam LB2 in S61 were the same as those of the second laser beam LB2 in S3 above.

[0141] In S62 included in S6, as shown in FIG. 9E, stress was applied to the glass plate 10 to form a fourth crack CR4 on the extraction surface 17. In the formation of the fourth crack CR4, thermal stress was applied to the glass plate 10 by irradiating the first laser beam LB1. The first laser beam LB1 was irradiated onto the first main surface 11 by an optical system including a condenser lens and the like. By moving the irradiation point along the first intersection line 18, the fourth crack CR4 was formed over the entire extraction surface 17. For the movement of the irradiation point, a 3D galvanometer scanner was used. The irradiation conditions of the first laser beam LB1 in S62 were the same as those in S2 except that the output was increased to 340W.

[0142] In S63 included in S6, as shown in FIG. 9F, a part of the glass plate 10 was extracted. The part of the glass plate 10 was the part including the center of curvature C, and the remaining part of the glass plate 10 was the part including the first crack CR1 and the second crack CR2.

[0143] In S4, as shown in FIG. 9G, stress was applied to the glass plate 10 to form a third crack CR3 spanning the tip of the first crack CR1 and the tip of the second crack CR2. In the formation of the third crack CR3, thermal stress was applied to the glass plate 10 by irradiating the first laser beam LB1. For the movement of the irradiation point of the first laser beam LB1, a 3D galvanometer scanner was used. The irradiation conditions of the first laser beam LB1 in S4 were the same as those in S2 except that the output was increased to 340W.

[0144] After S4, the unnecessary part from the third crack CR3 to the fourth crack CR4 shown in FIG. 9G was irradiated with the first laser beam LB1, and the unnecessary part was pulverized into a plurality of fragments by heat and removed. The irradiation conditions of the first laser beam LB1 at that time were the same as those in S2 except that the output was increased to 460W and the scanning speed in the in-plane direction was slowed down to 10 mm / s. After the unnecessary part was crushed, the glass plate 10 shown in FIGS. 9H and 9I could be obtained.

[0145] As described above, the method for processing a glass plate and the glass plate according to the present disclosure have been explained, but the present disclosure is not limited to the above-described embodiments. Within the scope described in the claims, various changes, modifications, substitutions, additions, deletions, and combinations are possible. Naturally, they also belong to the technical scope of the present disclosure.

[0146] This application claims priority based on Japanese Patent Application No. 2019-210499 filed with the Japan Patent Office on November 21, 2019, and incorporates the entire contents of Japanese Patent Application No. 2019-210499 into this application.

Explanation of Reference Numerals

[0147] 10 Glass plate 11 First main surface 12 Second main surface 13 First inclined surface 14 Second inclined surface 15 End face 151 First end face portion 152 Second end face portion BL1 First separation line BL1a Curved portion BL2 Second separation line C Center of curvature CR1 First crack CR2 Second crack CR3 Third crack D Modified portion

Claims

1. A first major surface; A second main surface facing opposite to the first main surface; One or more of a first inclined surface that intersects with the first main surface at an obtuse angle in a cross section perpendicular to a periphery of the first main surface, and a second inclined surface that intersects with the second main surface at an obtuse angle in the cross section; an end surface extending in a direction perpendicular to the first main surface from a tip of one or more of the first inclined surface and the second inclined surface, The arithmetic mean roughness of one or more of the first inclined surface and the second inclined surface is less than 0.1 μm; The arithmetic mean roughness of at least a portion of the end surface is 0.1 μm or more; A cover glass for an in-vehicle display, the cover glass being installed inside a vehicle with the first main surface facing a vehicle occupant.

2. having both the first inclined surface and the second inclined surface, The cover glass for an in-vehicle display according to claim 1 , wherein the end surface spans an end of the first inclined surface and an end of the second inclined surface.

3. The arithmetic mean roughness of the first inclined surface is 0.1 μm or more; The arithmetic mean roughness of the second inclined surface is less than 0.1 μm; The end surface is divided into a first end surface portion on the first main surface side and a second end surface portion on the second main surface side based on the plate thickness center, The arithmetic mean roughness of the first end surface portion is 0.1 μm or more, The cover glass for an in-vehicle display according to claim 2 , wherein the second end surface portion has an arithmetic mean roughness of less than 0.1 μm.

4. The cover glass for an in-vehicle display according to any one of claims 1 to 3, wherein a boundary between the first main surface and the first inclined surface includes a curved portion in a plan view.

5. The cover glass for an in-vehicle display according to claim 4 , wherein the radius of curvature of the curved portion is 0.5 mm or more and 1000 mm or less.

Images