JP2014224022A - Plate-like glass and plate-like glass cutting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide plate-like glass having high bending strength, and a cutting method capable of obtaining the plate-like glass with the high bending strength.SOLUTION: Plate-like glass comprises: a first translucent face and a second translucent face opposed to each other in a plate thickness direction of the plate-like glass; and an outer peripheral end face constituting a peripheral edge of the plate-like glass between the first translucent face and the second translucent face. The outer peripheral end face includes a second inclined face adjacent to the first translucent face, a first inclined face adjacent to the second inclined face, and a side face adjacent to the first inclined face. Surface roughness of the second inclined face is smaller than that of the first inclined face. An Ra value of the surface roughness of the first inclined face is 4.1 μm-100 μm, and an Ra value of the surface roughness of the second inclined is 0.0001 μm-4 μm.

Description

  The present invention relates to a plate glass used for, for example, a cover glass for a display device of an information device that can be carried and used, an optical filter glass of an image pickup apparatus (digital still camera, etc.), and a method for cutting the plate glass.

  As a cutting method of plate glass such as optical filter glass, after supporting the glass on a surface plate and forming a linear scribe groove with a cemented carbide scribe roller, the part where the scribe groove is formed from the opposite side A scribe cutting method is used in which a crack is generated by pressing and growing a crack starting from the bottom of the scribe groove in the thickness direction by the pressing force.

  As another method for cutting the sheet glass, there is a method using a dicing blade. In this method, a V-groove (inclined surface) is formed on a planned cutting line of glass and then reversed. Similarly, after forming a similar V-groove on the planned cutting line on the opposite surface, the glass is fully cut along the V-groove (Patent Documents 1 and 2).

  Further, regarding the cutting of sheet glass having a small plate thickness, it is a method using the above-mentioned dicing blade, and the bending length of the V-groove formed on the planned cutting line of the glass is set to a certain value or less so that a high bending strength is obtained. (Patent Document 3) has been proposed.

Japanese Patent Laid-Open No. 9-141646 JP 2004-142428 A JP 2007-277043 A

  However, information devices and imaging devices that can be carried and used are required to be thinner and lighter. For this reason, display device cover glass, optical filter glass, and the like used in these devices are required to have a thin plate thickness, and in addition to that, a strength equal to or higher than that of the glass before the plate thickness is reduced is required.

The inventor of the present invention proposed a method for cutting a glass substrate disclosed in Patent Document 3 described above, and found that the crack length of the V-groove forming surface is a factor in reducing the bending strength of the glass.
And further examination was carried out, and even if the plate thickness of the plate glass became very thin, the plate glass and the cutting method of the plate glass that can obtain high bending strength were found.
An object of the present invention is to provide a sheet glass having a high bending strength and a cutting method for obtaining a sheet glass having a high bending strength.

  As a result of various investigations, the present inventor has found that sheet glass having high bending strength by setting the surface roughness and crack length in the vicinity of the boundary between the light-transmitting surface and the outer peripheral end surface of the sheet glass to a predetermined range. It was found that can be obtained.

  That is, the plate-like glass of the present invention is made of plate-like glass, and the first light-transmitting surface and the second light-transmitting surface facing the plate-thickness direction of the plate-like glass, and the first light-transmitting surface and the second light-transmitting surface. An outer peripheral end surface that forms a peripheral edge of the sheet glass with the optical surface, and the outer peripheral end surface includes a second inclined surface adjacent to the first light transmitting surface and a second inclined surface adjacent to the second inclined surface. 1 inclined surface and a side surface adjacent to the first inclined surface, the surface roughness of the second inclined surface is smaller than the surface roughness of the first inclined surface, and the surface roughness of the first inclined surface is Ra The value is 4.1 μm to 100 μm, and the surface roughness of the second inclined surface is Ra value of 0.0001 μm to 4 μm.

  The sheet glass of the present invention is made of sheet glass, and includes a first light transmitting surface and a second light transmitting surface facing the plate thickness direction of the plate glass, and the first light transmitting surface and the second light transmitting surface. An outer peripheral end surface that forms a peripheral edge of the sheet glass with the optical surface, and the outer peripheral end surface includes a second inclined surface adjacent to the first light transmitting surface and a second inclined surface adjacent to the second inclined surface. 1 inclined surface and a side surface adjacent to the first inclined surface, the maximum value of the crack length of the second inclined surface is smaller than the minimum value of the crack length of the first inclined surface, The maximum value of the crack length is 100 μm or less.

  Moreover, the cutting | disconnection method of the sheet glass of this invention WHEREIN: The 1st V-groove formation which forms a 1st inclined surface with a 1st cross-section V-shaped dicing blade on the cutting projected line of the 1st light transmission surface of a sheet glass. And a first inclined surface formed in the first V-groove forming step using a second cross-sectional V-shaped dicing blade having an average abrasive grain size smaller than that of the first cross-sectional V-shaped dicing blade A second V-groove forming step for forming a second inclined surface on the same line, and dicing with a width smaller than the opening width of the V-groove formed in the first V-groove forming step and the second V-groove forming step And a step of cutting the sheet glass with a blade.

  Moreover, the cutting | disconnection method of the sheet glass of this invention WHEREIN: The 1st V-groove formation which forms a 1st inclined surface with a 1st cross-section V-shaped dicing blade on the cutting projected line of the 1st light transmission surface of a sheet glass. And a first inclined surface formed in the first V-groove forming step using a second cross-sectional V-shaped dicing blade having an average abrasive grain size smaller than that of the first cross-sectional V-shaped dicing blade A second V-groove forming step for forming a second inclined surface on the same line, a step of inverting the plate glass, and a first cross-section V-shaped on the planned cutting line of the second light transmitting surface of the plate glass A third V-groove forming step of forming a third inclined surface with a dicing blade, and a second cross-sectional V-shaped dicing blade having a larger cross-sectional V-shaped angle than the first cross-sectional V-shaped dicing blade. , On the same line as the third inclined surface formed in the third V-groove forming step A fourth V-groove forming step for forming the fourth inclined surface, and a dicing blade having a width smaller than the opening width of the V-groove formed in the first V-groove forming step to the fourth V-groove forming step. And a step of cutting glass.

  According to the present invention, a sheet glass having high bending strength can be obtained by setting the surface roughness and crack length in the vicinity of the boundary between the light-transmitting surface and the outer peripheral end surface of the sheet glass within a predetermined range. Moreover, according to the cutting method of this invention, the cutting method for obtaining plate glass with high bending strength can be provided.

It is sectional drawing (a) and the perspective view (b) of the sheet glass 100 which concern on embodiment. It is a fragmentary sectional view of sheet glass 100 concerning an embodiment. It is a fragmentary sectional view of plate glass 200 concerning other embodiments. It is sectional drawing of the sheet glass 300 which concerns on other embodiment. It is sectional drawing of the sheet glass 400 which concerns on other embodiment. It is a process flow figure of the cutting method of sheet glass concerning an embodiment. It is a process flow figure of the cutting method of sheet glass concerning other embodiments. It is a photograph which shows the processing state of an Example and the comparative example 3.

  Hereinafter, the plate glass according to the embodiment will be described with reference to the drawings.

(Embodiment)
Drawing 1 is a sectional view (a) and perspective view (b) of sheet glass 100 concerning an embodiment. As shown in FIG. 1, the plate-like glass 100 according to the present embodiment is used for, for example, a solid-state imaging device such as a digital still camera (for example, Charge Coupled Device (hereinafter, CCD) or Complementary Metal Oxide Semiconductor (CMOS)). Optical glass such as cover glass and near infrared cut filter.
The plate-like glass 100 is formed between the first light-transmitting surface 10 and the second light-transmitting surface 20 facing each other in the plate thickness direction, and between the first light-transmitting surface 10 and the second light-transmitting surface 20. And an outer peripheral end face 30 constituting a peripheral edge.

  FIG. 2 is a partial cross-sectional view showing details of the outer peripheral end face 30 of the sheet glass 100 according to the embodiment. An outer peripheral end surface 30 of the sheet glass 100 is adjacent to the second inclined surface 32 adjacent to the first light transmitting surface 10, the first inclined surface 31 adjacent to the second inclined surface 32, and the first inclined surface 31. It consists of a side surface 33.

  The first light transmitting surface 31 and the second light transmitting surface 32 are surfaces through which light is transmitted when the glass sheet 100 is used in an imaging device or the like. Each translucent surface of the plate glass 100 has a predetermined surface state according to the purpose of use. For example, when used for an optical filter glass of an imaging device, it is necessary to provide a surface without high flatness or roughness.

  The second inclined surface 32 is a surface that is formed between the first light transmitting surface 10 and the first inclined surface 31 and is inclined toward the side surface 33. The first inclined surface 31 is a surface that constitutes between the second inclined surface 32 and the side surface 33. The first inclined surface 31, the second inclined surface 32, and the side surface 33 constitute an outer peripheral end 30 of the sheet glass 100. Therefore, when the external shape of the sheet glass 100 is a rectangle, each has four surfaces along the outer periphery. Moreover, when the external shape of the plate glass 100 is circular, each has one surface. In addition, the external shape of the sheet glass 100 is not limited to these, A suitable shape can be used according to a use.

  The plate-like glass 100 may be subjected to an external force that causes the light-transmitting surface to have a convex shape during the manufacturing process or use. With respect to the action of such a force, the starting point of the crack when the glass sheet 100 is broken is in the vicinity of the boundary between the translucent surface and the outer peripheral side surface. Therefore, the plate glass 100 according to the present invention has a high bending to the plate glass 100 by setting the surface roughness or crack length of the second inclined surface 32 that is the boundary between the light transmitting surface and the outer peripheral side surface as follows. Strength can be imparted.

  The second inclined surface 32 has a surface roughness smaller than the surface roughness of the first inclined surface 31, and the surface roughness of the first inclined surface 31 has a Ra value of 4.1 μm to 100 μm, the second inclined surface. The surface roughness Ra of the surface 32 is 0.0001 μm to 4 μm. By doing in this way, since the surface roughness of the 2nd inclined surface 32 is very smooth, when the external force which the said 1st translucent surface 10 becomes convex shape acts on the sheet glass 100 Even if it exists, the crack used as the starting point of destruction hardly exists in the said 2nd inclined surface 32. FIG. Therefore, high bending strength can be imparted to the sheet glass 100.

If the surface roughness of the second inclined surface 32 is larger than the surface roughness of the first inclined surface 31, there is a possibility that there is a scratch that becomes a starting point of destruction. When the surface roughness of the second inclined surface 32 is less than 0.0001 μm, it takes time for processing and the productivity is poor. Moreover, when it exceeds 4 micrometers, there exists a possibility that the crack used as the starting point of destruction may exist. When the surface roughness of the first inclined surface 31 is less than 4.1 μm, it takes time for processing and the productivity is poor. On the other hand, if the thickness exceeds 100 μm, scratches present on the first inclined surface 31 may be the starting point of destruction.
In the present invention, the surface roughness means an arithmetic average roughness (Ra) based on JIS B 0601: 2001.

  In the second inclined surface 32, the maximum value of the crack length existing is smaller than the minimum value of the crack length existing in the first inclined surface 31, and the maximum value of the existing crack length is 100 μm or less. By doing so, there is almost no scratch on the second inclined surface 32 as a starting point of destruction. Therefore, even when an external force is applied to the plate glass 100 so that the first light-transmitting surface 10 has a convex shape, the plate glass 100 is not easily broken and high bending strength can be imparted to the plate glass 100.

  If the maximum value of the crack length existing on the second inclined surface 32 is larger than the minimum value of the crack length existing on the first inclined surface 31, the existing crack may be a starting point of destruction. The second inclined surface 32 has a maximum crack length that is smaller than the minimum crack length that exists in the first inclined surface 31. If the maximum value of the crack length exceeds 100 μm, the crack is the starting point of fracture. There is a risk of becoming.

The crack length of each inclined surface in the present invention is the length of the crack when the crack is projected on the light-transmitting surface of the sheet glass 100 with respect to the crack extending into the sheet glass 100 starting from each inclined surface. It is what you point to. Note that a crack generated at the boundary between the first light transmitting surface 10 and the second inclined surface 32 is regarded as a crack of the second inclined surface 32. Further, a crack generated at the boundary between the first inclined surface 31 and the second inclined surface 32 is regarded as a crack of the first inclined surface 31.
The crack length can be measured by the method described below. Polishing is performed from the side surface of the sheet glass 100 in a direction parallel to the first light-transmitting surface 10. Next, the polished portion of the plate glass 100 is immersed in hydrochloric acid (concentration: 7%) to make it easier to recognize cracks. Then, the depth of the crack (distance to the bottom of the crack) is measured with a laser microscope. The above-described polishing amount (amount polished in the direction parallel to the first light-transmitting surface from the side surface) and the crack depth measured with a laser microscope are summed to obtain the crack length.

  The first inclined surface 31 and the second inclined surface 32 may have different angles with respect to the first light transmitting surface 10. This means that the first inclined surface 31 and the second inclined surface 32 are configured by different planes. In this case, the angle formed by the second inclined surface 32 with respect to the first inclined surface 31 is preferably more than 0 ° and not more than 45 °. When the angle formed exceeds 45 °, the boundary between the first inclined surface 31 and the second inclined surface 32 becomes a sharp state, so that chipping is likely to occur and when the sheet glass 100 is transported or the like. May cause dust.

Further, as shown in FIG. 3, the first inclined surface 31 and the second inclined surface 32 may have the same angle with respect to the first light transmitting surface 10. This means that the first inclined surface 31 and the second inclined surface 32 are formed of the same plane. By doing in this way, the boundary of the said 1st inclined surface 31 and the said 2nd inclined surface 32 is not clear, and it can suppress that a chip | tip arises in a boundary.
The angle formed by the second inclined surface 32 with respect to the first inclined surface 31 refers to a dihedral angle between the adjacent first inclined surface and the second inclined surface 32, and the first inclined surface. It is defined as the angle between the normal of the surface 31 and the normal of the second inclined surface 32. That is, it means an angle indicated by θ in FIG. 2, and an angle between a line perpendicular to the first inclined surface 31 and a line perpendicular to the second inclined surface 32 in the cross-sectional view of the sheet glass 100. Say.

The side surface 33 is adjacent to the first inclined surface 31 and constitutes the outermost periphery of the outer peripheral end surface 30. The side surface 33 is substantially perpendicular to the first light-transmitting surface 10, and an angle formed with respect to the first light-transmitting surface 10 may be 90 ° ± 5 °, or may be formed of a curved surface. Good.
When the side surface 33 is substantially perpendicular to the first light-transmitting surface 10 and the angle formed with respect to the first light-transmitting surface 10 is 90 ° ± 5 °, the plate-like glass 100 is assembled to a device or the like. Positioning is easy using the side surface 33. On the other hand, when the angle formed by the side surface 33 with respect to the first light-transmitting surface 10 is out of the range of 90 ° ± 5 °, positioning is performed using the side surface 33 when the sheet glass 100 is assembled to an apparatus or the like. Since it becomes difficult to perform, it is not preferable.
Further, when the side surface 33 is formed of a curved surface, the boundary between the side surface 33 and the first inclined surface 31 can be obscured, so that it is possible to prevent the boundary from being chipped.

The first light transmitting surface 10 may be provided with a dielectric film 40 on the surface as shown in FIG. When the dielectric film 40 having an internal stress of compressive stress is provided on the first light transmitting surface 10, the crack generated in the second inclined surface 32 is suppressed from being stretched by the internal stress of the dielectric film 40. Therefore, the bending strength of the plate glass 400 can be improved.
Further, the first light transmitting surface 10 is provided with the dielectric film 40 on the surface, and thus has an effect of suppressing contact between the glass sheet 400 and the external atmosphere. For example, since the contact between the glass sheet 400 and moisture is blocked by the dielectric film 40, damage to each light-transmitting surface is suppressed even if the glass has low water resistance. The weather resistance and water resistance of the glass 400 can be improved. The dielectric film 40 may be provided on both the first light transmitting surface 10 and the second light transmitting surface 20.

The dielectric film 40 is composed of a multilayer film or a single layer film in which dielectric films having different refractive indexes are laminated. The dielectric film 40 is an antireflection film that reduces the amount of reflected light on the surface of the plate glass 400, an IR cut film that cuts infrared rays, or a UV / IR cut film that cuts ultraviolet rays and infrared rays. Also good. The dielectric film 40 is, for example, a single layer film of MgF ₂ , a mixed film of Al ₂ O ₃ / TiO ₂ and ZrO ₂ / a multilayer film in which MgF ₂ is laminated, or an alternating multilayer film of SiO ₂ / TiO _2. It consists of These single layer / multilayer films are formed on each light-transmitting surface of the sheet glass 400 by a film forming method such as vacuum deposition or sputtering. The dielectric film 40 preferably has a physical film thickness of 0.2 μm to 8 μm.

  The stress acting on the sheet glass 400 due to the internal stress of the dielectric film 40 is preferably 5 MPa to 150 MPa. If the stress acting on the sheet glass 400 is less than 5 MPa, the effect of suppressing breakage of the sheet glass 400 cannot be sufficiently obtained. Further, if the stress acting on the sheet glass 400 exceeds 150 MPa, the amount of warpage becomes too large. The stress acting on the plate glass 400 is preferably 10 MPa to 125 MPa, more preferably 10 MPa to 100 MPa.

The stress acting on the sheet glass 400 can be calculated by converting the curvature radius of the warp from the amount of warp of the sheet glass 400, and the following Stoney formula (formula (1)) (plate glass 400). Is a circular substrate).
^{σ = Et 2/6 (1} -ν) Rt '··· (1)
Where, σ: stress, E: Young's modulus of the sheet glass, t: plate thickness of the sheet glass, ν: Poisson's ratio of the optical glass 100, R: curvature radius of warpage of the sheet glass, t ′: optical thin film thickness.
When the plate glass 400 is a strip substrate, the stress acting on the plate glass 400 is calculated using the following equation (2).
^{σ = Et 2/3 (1} -ν) Rt '··· (2)
As shown in FIG. 4, the second inclined surface 32 may be adjacent to each of the first light transmitting surface 10 and the second light transmitting surface 20 on the outer peripheral end surface 30 of the plate glass 300. By doing in this way, the bending strength of the sheet glass 300 can be made higher. In this case, the outer peripheral end surface 30 of the sheet glass 300 includes a second inclined surface 32 adjacent to each light transmitting surface, a first inclined surface 31 adjacent to each second inclined surface 32, and each first inclined surface. And a side surface 33 sandwiched between 31.

As the plate glass, a glass having an appropriate composition can be used depending on the application. For example, borosilicate glass, quartz glass, soda lime glass, non-alkali glass and the like are exemplified. In the case of an optical filter glass that absorbs light in the near-infrared wavelength region used in an imaging device, as the plate glass 100, an absorption type in which Cu ²⁺ (ion) is added to fluorophosphate glass or phosphate glass. Glass is mentioned. Further, the plate-like glass of the present invention remarkably exhibits the effect of high bending strength, particularly when the plate thickness is thin. Therefore, the plate thickness of the plate glass 100 is not particularly limited, but can be preferably applied to glass having a plate thickness of less than 0.3 mm, and can be preferably applied to glass having a plate thickness of less than 0.2 mm.

  The outer peripheral side surface 30 of the sheet glass 100 has a surface roughness of the side surface 33 smaller than the surface roughness of the first inclined surface 31, and a surface roughness of the second inclined surface 32 smaller than the surface roughness of the side surface 33. You may be in the state. Since the surface state of the second inclined surface 32 is strongly involved in the bending strength of the sheet glass 100 as described above, it is desirable that the surface roughness is as small as possible. The side surface 33 may be used for positioning when the plate-like glass 100 is assembled in an apparatus, and the second inclined surface 32 has a surface roughness in consideration of chipping due to contact with other members. However, the surface roughness is preferably smaller than that of the first inclined surface 31. On the other hand, the first inclined surface 31 is less involved in the bending strength of the sheet glass 100 and is less likely to come into contact with other members. Therefore, consideration like the 2nd inclined surface 32 and the said side 33 is unnecessary, and it is preferable that surface roughness is larger than the said 2nd inclined surface 32 and the said side 33 so that processing time may become short. By doing in this way, it can contribute to the productivity of the sheet glass 100.

  Next, the cutting method of the sheet glass 100 of this invention is demonstrated. FIG. 6 is a process flow diagram showing an embodiment of the method for cutting sheet glass of the present invention.

  Hereinafter, the flow of the process from the sheet glass before cutting to the sheet glass 100 after cutting will be briefly described with reference to FIG. First, a glass raw material is melted and molded to obtain a flat glass. Then, if necessary, the light-transmitting surface of the glass is polished to finish the plate glass before cutting so as to have a desired surface state (molding step of the plate glass before cutting). Subsequently, the 1st inclined surface 31 is formed with the 1st cross-section V-shaped dicing blade 50 on the cutting projected line of the 1st translucent surface 10 of the said plate-shaped glass (1st V-groove formation process). Next, a first slope formed in the first V-groove forming step using a second cross-sectional V-shaped dicing blade 60 having an average abrasive grain size smaller than that of the first cross-sectional V-shaped dicing blade 50. The second inclined surface 32 is formed on the same line as the surface 31 (second V groove forming step). Next, the plate glass on which the first inclined surface 31 and the second inclined surface 32 are formed is inverted (plate glass inversion step). Next, the sheet glass is cut using the cutting dicing blade 70 having a width smaller than the opening width of the V groove formed in the first V groove forming step and the second V groove forming step (cutting step); Is provided.

  In the step of forming the plate glass before cutting, the prepared glass raw material is melted in a glass melting furnace, and the molten glass is formed into a plate glass. As a forming method, an appropriate method such as a float method, a roll-out method, and an overflow down-draw method for forming molten glass into a plate shape can be used. Moreover, after filling molten glass into a shaping | molding die and shape | molding block-shaped glass, plate-like glass may be obtained by cut | disconnecting a block and grind | polished a translucent surface.

  In the first V-groove forming step, the first inclined surface 31 is formed by the first cross-section V-shaped dicing blade 50 on the planned cutting line of the first light transmitting surface 10 of the plate glass. The processing depth of the first inclined surface 31 is set to a depth less than the thickness of the plate glass so as not to cut the plate glass.

  In the second V groove forming step, the second inclined surface 32 is formed on the same line as the first inclined surface 31 formed in the first V groove forming step. The second cross-sectional V-shaped dicing blade 60 used in the second V-groove forming step has an average abrasive grain size smaller than that of the first cross-sectional V-shaped dicing blade 50 used in the first V-groove forming step. . Thereby, the surface roughness of the second inclined surface 32 is smaller than the surface roughness of the first inclined surface 31. Alternatively, the maximum value of the crack length of the second inclined surface 32 is smaller than the minimum value of the crack length of the first inclined surface 31. Thereby, the bending strength of the sheet glass 100 after cutting can be increased. The processing depth of the second inclined surface 32 is set to a depth less than the thickness of the plate glass so as not to cut the plate glass.

  The inversion step is necessary when the cutting dicing blade 70 is inserted from the second light transmitting surface 20 in the cutting step described later, but is not necessary when the cutting dicing blade 70 is inserted from the first light transmitting surface 10. , Any process.

  The cutting step uses a cutting dicing blade 70 having a width smaller than the opening width of the V-groove formed in the first V-groove forming step and the second V-groove forming step, and forms a plate shape along the planned cutting line. This is a process of completely cutting glass.

  When forming the dielectric film 40 on the 1st translucent surface 10, it carries out between the shaping | molding process of the plate glass before the said cutting | disconnection, and the said 1st V groove formation process, or after a cutting process. As a method of forming the dielectric film 40 on the first light transmitting surface 10, a vacuum deposition method, an ion assist deposition method (ion beam assist method), an ion plating method, a sputtering method, an ion beam sputtering method, or the like is used. it can.

  The second cross-section V-shaped dicing blade 60 preferably has a larger cross-section V-shaped angle than the first cross-section V-shaped dicing blade 50. In this way, only a part of the first inclined surface 31 formed in the first V groove forming step adjacent to the first light transmitting surface 10 is formed as the second inclined surface 32. Therefore, since the processing area by the second V-shaped dicing blade 60 is small and the resistance during processing is small, the crack length generated in the second inclined surface 32 can be reduced.

  The second cross-sectional V-shaped dicing blade 60 preferably has the same cross-sectional V-shaped angle as the first cross-sectional V-shaped dicing blade 50. If it does in this way, all the 1st inclined surfaces 31 formed in the 1st V-groove formation process will be cut by the 2nd V-groove formation process, and will become the 2nd inclined surface 32. Therefore, since all the cracks generated in the first inclined surface 31 are removed in the second V-groove forming step, all the inclined surfaces formed in the sheet glass 100 have a small surface roughness or a crack length. Since it is small, the plate-like glass 100 provided with high bending strength can be obtained.

  The first and second cross-sectional V-shaped dicing blades used in the first V-groove forming step and the second V-groove forming step may be a resin bond blade, a resin-metal bond, or a metal bond blade. preferable. The resin bond blade is a blade in which a binder for bonding abrasive grains is made of a resin agent. The metal bond blade is a blade formed by sintering abrasive grains and metal powder. The resin-metal bond blade is a blade having both. Since these blades have a weak abrasive holding force and are soft to the plate glass during processing, cracks generated on the processed surface can be reduced when forming each inclined surface. On the other hand, in the case of an electrodeposition blade in which the abrasive grains are fixed by electrodeposition, the base metal and the abrasive grain holding force are strong, and the contact with the glass sheet at the time of processing is strong. Since it becomes large, it is not preferable. When the resin bond blade and the metal bond blade are compared, the resin bond blade has a smaller abrasive length, but the crack length is smaller, but the life of the blade is shorter. On the contrary, the metal bond blade has a longer crack life, but the life of the blade is longer as the abrasive holding power is greater. Therefore, an appropriate type of bond can be selected and used depending on the glass composition of the sheet glass. As the abrasive grains, appropriate ones such as diamond can be used.

The second cross-sectional V-shaped dicing blade 60 used in the second V-groove forming step preferably uses an average abrasive grain size of 1 μm to 16 μm. Thereby, the surface roughness of the 2nd inclined surface 32 can be made small, and the crack length to generate | occur | produce can be made small. The second cross-section V-shaped dicing blade 60 preferably has an average abrasive grain size of 5 μm to 12 μm.
On the other hand, the first cross-sectional V-shaped dicing blade 50 used in the first V-groove forming step preferably uses an average abrasive grain size of 17 μm to 80 μm. Thereby, it is possible to process with high productivity while suppressing cracks generated in the first inclined surface 31. The first cross-section V-shaped dicing blade 50 has a preferable average abrasive grain size of 20 μm to 60 μm.

  Next, other embodiment of the cutting method of the sheet glass of this invention is described. FIG. 7 is a process flow diagram showing another embodiment of the sheet glass cutting method of the present invention. In addition, description is abbreviate | omitted when it is the same as the content demonstrated above.

  Hereinafter, the flow of the process from the sheet glass before cutting to the sheet glass 300 after cutting will be briefly described with reference to FIG. First, a glass raw material is melted and molded to obtain a flat glass. Then, if necessary, the light-transmitting surface of the glass is polished to finish the plate glass before cutting so as to have a desired surface state (molding step of the plate glass before cutting). Subsequently, the 1st inclined surface 31 is formed with the 1st cross-section V-shaped dicing blade 50 on the cutting projected line of the 1st translucent surface of the said sheet glass (1st V-groove formation process). Next, a first slope formed in the first V-groove forming step using a second cross-sectional V-shaped dicing blade 60 having an average abrasive grain size smaller than that of the first cross-sectional V-shaped dicing blade 50. The second inclined surface 32 is formed on the same line as the surface 31 (second V groove forming step). Next, the plate glass on which the first inclined surface 31 and the second inclined surface 32 are formed is inverted (plate glass inversion step). Next, a third inclined surface is formed by the first cross-section V-shaped dicing blade 50 on the planned cutting line of the second light transmitting surface 20 of the plate glass (third V groove forming step). Next, a third V-groove forming step is performed using the second V-shaped dicing blade 60 having a V-shaped cross-sectional angle larger than that of the first V-shaped dicing blade 50. A fourth inclined surface is formed on the same line as the inclined surface (second V groove forming step). Next, the sheet glass is cut using the cutting dicing blade 70 having a width smaller than the opening width of the V groove formed in the second V groove forming step and the fourth V groove forming step (cutting step); Is provided.

The cutting method of another embodiment is the same as the first light transmitting surface 10 side on the second light transmitting surface 20 side, in that a third inclined surface and a fourth inclined surface are provided. It is a difference. The first inclined surface 31 and the third inclined surface are both formed using the first cross-sectional V-shaped dicing blade 50, and thus the obtained surface states are almost the same. Moreover, since both the 2nd inclined surface 32 and the 4th inclined surface are formed using the 2nd cross-section V-shaped dicing blade 60, the surface state obtained is substantially the same.
By using the cutting method of another embodiment, the plate-like glass 300 includes the inclined surfaces on both the first light transmitting surface 10 and the second light transmitting surface 20. Therefore, compared with the case where each inclined surface is provided only in the 1st translucent surface 10, the plate-like glass 300 provided with higher bending strength can be obtained.

  A known dicing apparatus can be used for the above-described method for cutting the glass sheet. In addition, the plate-like glass and the processing table are fixed in each process by attaching the plate-like glass to the ultraviolet curable dicing tape and fixing the ultraviolet curable dicing tape to the processing table by vacuum suction. In each V-groove forming step, the processing position can be adjusted using a camera so that the V-groove does not deviate from the planned cutting line.

EXAMPLES Hereinafter, although it demonstrates in detail based on the Example of this invention, this invention is not limited only to these Examples.
Fluorophosphate glass (manufactured by AGC Techno Glass, NF-50, plate thickness 0.3 mm, dimensions 20 mm × 10 mm) was prepared as the plate-like glass of Examples and Comparative Examples.
A dicer device (A-WD-200T, manufactured by Tokyo Seimitsu Co., Ltd.) was used for each V-groove forming step and cutting step of the sheet glass. The blade used in the cutting step (full cut) is a metal bond blade (# 1000). Table 1 shows the conditions of each V-groove forming step and the specifications of each V-shaped dicing blade used in the examples and comparative examples. The blade feed speed in each V-groove forming step and cutting step is 10 mm / sec.

  The plate-like glass of Examples and Comparative Examples was processed so that each inclined surface was provided only on the first light-transmitting surface side. In the sheet glass of the example, the angle formed by the second inclined surface with respect to the first inclined surface was 15 °. Further, in the side surfaces of the examples and the comparative examples, the angle formed with respect to the first light transmitting surface was within a range of 90 ° ± 5 °.

The following was evaluated about the plate-like glass which performed the cutting method of an Example and each comparative example.
The bending strength of the sheet glass was determined by measuring the maximum load when the test piece broke using a four-point bending strength test method described in JIS R1601 (Fine ceramic bending strength test method). The number of samples is 15 each.
The surface roughness of the second inclined surface was measured using a laser microscope (manufactured by Keyence Corporation, shape measurement laser microscope VK-X100).
The crack length (minimum value) of the first inclined surface and the crack length (maximum value) of the second inclined surface were measured by the method described in Paragraph 0025.
Table 1 shows the test results.

From the test results, it was confirmed that the glass sheet of the example had higher bending strength than each comparative example.
In Comparative Example 1 and Comparative Example 2, only the first inclined surface was formed in the first V-groove forming step, but the bending strength was lower than that in Example.
In Comparative Example 2, a V-shaped dicing blade having a small average abrasive grain size was used in the first V-groove forming step, but the bending strength was low. This is because even if a blade with a small average abrasive grain size and a small cutting force is used in the first V-groove forming step with a large amount of cutting, the crack length generated on the inclined surface is not reduced, and conversely to the glass This suggests that the damage is large and the crack length generated on the inclined surface increases.
In Comparative Example 3, each inclined surface was formed by a two-stage process including a first V-groove forming process and a second V-groove forming process. However, since the same V-shaped dicing blade is used in the first V-groove forming step and the second V-groove forming step, it is almost equivalent to Comparative Example 1 in which only the first V-groove forming step is performed. The bending strength of the sheet glass. This is a V-shaped cross section used for the second V-groove forming process even when the second inclined surface is formed by the two-stage process of the first V-groove forming process and the second V-groove forming process. This suggests that the specifications of the dicing blade are important.

  The photograph of the processing state of plate glass is shown in FIG. 8 ((a): Example, (b): Comparative Example 3). The photograph in FIG. 8 is a photograph of the second inclined surface and the first inclined surface from the first light transmitting surface side. As can be seen from FIG. 8, it can be seen that the plate-like glass of the example has a very smooth second inclined surface. On the other hand, the flat glass of the comparative example 3 shows that the smoothness of a 2nd inclined surface is inferior to an Example.

  The plate-like glass of the present invention is thin and is applied to a bending stress, for example, a cover glass used for a solid-state imaging device (CCD or CMOS) such as a digital still camera or an optical such as a near-infrared cut filter. It can be suitably used for glass.

  DESCRIPTION OF SYMBOLS 10 ... 1st light transmission surface, 20 ... 2nd light transmission surface, 30 ... Outer peripheral edge part, 31 ... 1st inclined surface, 32 ... 2nd inclined surface, 33 ... Side surface, 40 ... Dielectric film, 50 ... 1st Sectional V-shaped dicing blade, 60 ... Second sectional V-shaped dicing blade, 70 ... Cutting dicing blade, 100 ... Plate glass, 200 ... Plate glass, 300 ... Plate glass, 400 ... Plate glass .

Claims (10)

The plate-like glass is formed between a first light-transmitting surface and a second light-transmitting surface that are made of plate-like glass and are opposed to each other in the thickness direction of the plate-like glass, and the first and second light-transmitting surfaces. An outer peripheral end surface constituting the periphery of
The outer peripheral end surface includes a second inclined surface adjacent to the first light-transmitting surface, a first inclined surface adjacent to the second inclined surface, and a side surface adjacent to the first inclined surface,
The surface roughness of the second inclined surface is smaller than the surface roughness of the first inclined surface,
The surface roughness of the first inclined surface has a Ra value of 4.1 μm to 100 μm,
The surface roughness of the second inclined surface has an Ra value of 0.0001 μm to 4 μm,
A sheet glass characterized by the following. The plate-like glass is formed between a first light-transmitting surface and a second light-transmitting surface that are made of plate-like glass and are opposed to each other in the thickness direction of the plate-like glass, and the first and second light-transmitting surfaces. An outer peripheral end surface constituting the periphery of
The outer peripheral end surface includes a second inclined surface adjacent to the first light-transmitting surface, a first inclined surface adjacent to the second inclined surface, and a side surface adjacent to the first inclined surface,
The maximum value of the crack length of the second inclined surface is smaller than the minimum value of the crack length of the first inclined surface,
The maximum value of the crack length of the second inclined surface is 100 μm or less,
A sheet glass characterized by the following.   The sheet glass according to claim 1 or 2, wherein the first inclined surface and the second inclined surface have the same angle with respect to the first light-transmitting surface.   The angle between the first inclined surface and the second inclined surface formed by the second inclined surface with respect to the first inclined surface is more than 0 ° and not more than 45 °. The plate-like glass described in 1.   5. The side surface is substantially perpendicular to the first light transmitting surface, and an angle formed by the side surface with respect to the first light transmitting surface is 90 ° ± 5 °. The plate glass according to any one of the above.   The plate glass according to any one of claims 1 to 5, wherein a dielectric film is provided on the first light transmitting surface. A first V-groove forming step of forming a first inclined surface with a first cross-section V-shaped dicing blade on a cutting line of the first light-transmitting surface of the sheet glass;
Using a second cross-sectional V-shaped dicing blade having an average abrasive grain size smaller than that of the first cross-sectional V-shaped dicing blade, the first inclined surface formed in the first V-groove forming step is on the same line. A second V-groove forming step for forming a second inclined surface on
Cutting the plate glass with a dicing blade having a width smaller than the opening width of the V groove formed in the first V groove forming step and the second V groove forming step. A first V-groove forming step of forming a first inclined surface with a first cross-section V-shaped dicing blade on a cutting line of the first light-transmitting surface of the sheet glass;
Using a second cross-sectional V-shaped dicing blade having an average abrasive grain size smaller than that of the first cross-sectional V-shaped dicing blade, the first inclined surface formed in the first V-groove forming step is on the same line. A second V-groove forming step for forming a second inclined surface on
Reversing the sheet glass;
A third V-groove forming step of forming a third inclined surface with a first cross-section V-shaped dicing blade on a cutting line of the second light-transmitting surface of the sheet glass;
Same as the third inclined surface formed in the third V-groove forming step using a second cross-sectional V-shaped dicing blade having a cross-sectional V-shaped angle larger than that of the first cross-sectional V-shaped dicing blade. A fourth V-groove forming step of forming a fourth inclined surface on the line;
Cutting the plate glass with a dicing blade having a width smaller than the opening width of the V groove formed in the first V groove forming step to the fourth V groove forming step.   The sheet glass according to claim 7 or 8, wherein the second cross-sectional V-shaped dicing blade has a larger cross-sectional V-shaped angle than the first cross-sectional V-shaped dicing blade. Cutting method.   9. The sheet glass according to claim 7, wherein the second cross-sectional V-shaped dicing blade has the same cross-sectional V-shaped angle as that of the first cross-sectional V-shaped dicing blade. Cutting method.

Images