JP7230816B2 - Glass plate and its manufacturing method - Google Patents

Description

The present invention relates to a glass plate and its manufacturing method.

The spectral sensitivity of solid-state image sensors such as CCDs and CMOS used in digital still cameras and video cameras is highly sensitive to light in the near-infrared region. Visibility correction members are generally used to match the characteristics.

As the visibility correcting member, for example, as disclosed in Patent Document 1, a glass plate having an optical film having an infrared shielding function formed on the main surface of the glass plate is used. In some cases, an optical film having an antireflection function is formed to prevent reflection on the surface of the glass plate.

WO2013/077375

By the way, glass plates used for solid-state imaging devices and the like are being made thinner. Along with this, there is a problem that the glass plate is easily damaged by impact during transportation. In particular, such breakage of the glass plate often occurs due to the progress of cracks originating from the edge surfaces of the glass plate, and further improvement in the strength of the edge surfaces is desired.

An object of the present invention is to improve the end face strength of a glass plate and reduce breakage of the glass plate.

The present invention, which has been devised to solve the above-described problems, provides a glass plate having a pair of front and back main surfaces and an end face connecting each end of the pair of main surfaces, wherein the end face has a plurality of crater-shaped recesses. 50% or more of the first recesses in which the maximum value of the linear distance between two points on the outer periphery of the top is 0.5 μm or more among the recesses included in an arbitrary 30 μm square range of the end face It is characterized by According to such a configuration, on the end face, relatively large first concave portions having a maximum linear distance of 0.5 μm or more between two points on the outer periphery of the top portion occupy the majority. Therefore, even if an external force such as an impact acts on the end face of the glass plate, it is considered that the force can be dispersed by the relatively large first concave portion formed on the end face. As a result, cracks originating from the end face of the glass plate are less likely to develop, and breakage of the glass plate can be reduced.

In the above configuration, it is preferable that the total number of recesses included in an arbitrary range of 30 μm square of the end face is 50 or more and 300 or less.

In the above configuration, the depth of the first concave portion may be 0.5 μm or more.

In the above configuration, an optical film may be formed on at least one main surface.

In this case, the optical film is preferably at least one of an antireflection film, an infrared shielding film, an ultraviolet shielding film, and an ultraviolet and infrared shielding film.

In the above structure, it is preferable that the glass plate contains 25% or more of P ₂ O ₅ as a composition in mass %.

The present invention, which has been devised to solve the above problems, provides a method for manufacturing a glass plate having a pair of front and back main surfaces and end faces connecting the ends of the pair of main surfaces, wherein at least the end faces of the glass plate are The glass plate is made of phosphate-based glass, the etching solution is an alkaline detergent, and the removal thickness of the end surface of the glass plate by the etching solution is 1 μm or more. and According to such a configuration, the end face of the glass plate is removed by the etchant, and a plurality of crater-shaped concave portions are formed in the end face of the glass plate. By performing the etching process under the above conditions, the proportion of the first concave portion can be set to 50% or more within an arbitrary range of 30 μm square of the end face. Therefore, cracks originating from the end face of the glass plate are less likely to develop, and breakage of the glass plate can be reduced.

In the above configuration, the etching solution preferably contains an alkali salt of a chelating agent as an alkali component.

The above configuration may further include a film forming step of forming an optical film on at least one main surface of the glass plate before the etching step.

ADVANTAGE OF THE INVENTION According to this invention, the edge strength of a glass plate can be improved and breakage of a glass plate can be reduced.

It is sectional drawing which shows the glass plate which concerns on 1st embodiment. It is an enlarged plan view which shows typically the end surface state of the glass plate which concerns on 1st embodiment. It is an expanded sectional view which shows typically the end surface state of the glass plate which concerns on 1st embodiment. It is sectional drawing which shows the etching process included in the manufacturing method of the glass plate which concerns on 1st embodiment. It is a figure for demonstrating an example of the measuring method of the removal thickness of the glass plate end surface by an etching. It is sectional drawing which shows the glass plate which concerns on 2nd embodiment. It is a top view which shows the glass plate which concerns on 2nd embodiment. It is sectional drawing which shows the film-forming process included in the manufacturing method of the glass plate which concerns on 2nd embodiment. It is a top view which shows the cutting process included in the manufacturing method of the glass plate which concerns on 2nd embodiment. It is sectional drawing which shows the etching process included in the manufacturing method of the glass plate which concerns on 2nd embodiment. It is sectional drawing which shows the glass plate which concerns on 3rd embodiment. It is sectional drawing which shows the state of the early stages of the cutting process which serves as the chamfering process included in the manufacturing method of the glass plate which concerns on 3rd embodiment. It is sectional drawing which shows the state of the middle stage of the cutting process which serves as the chamfering process included in the manufacturing method of the glass plate which concerns on 3rd embodiment. It is sectional drawing which shows the state of the final stage of the cutting process which serves as the chamfering process included in the manufacturing method of the glass plate which concerns on 3rd embodiment. It is sectional drawing which shows the modification of the chamfering process included in the manufacturing method of the glass plate which concerns on 3rd embodiment. It is sectional drawing which shows the etching process included in the manufacturing method of the glass plate which concerns on 3rd embodiment. It is sectional drawing which shows the glass plate which concerns on 4th embodiment. It is sectional drawing which shows the film-forming process included in the manufacturing method of the glass plate which concerns on 4th embodiment. It is sectional drawing which shows the etching process included in the manufacturing method of the glass plate which concerns on 4th embodiment. It is a microscope image of an example. It is a microscope image of an example.

A glass plate and a method for manufacturing the same according to embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
As shown in FIG. 1, the glass plate 1 according to the first embodiment includes a pair of front and back main surfaces 1a and an end surface 1b connecting the ends of both main surfaces 1a. Although the glass plate 1 is formed in a square shape, it is not limited to this shape, and may be, for example, a triangle, a polygon with five or more sides, or a circle. In this embodiment, the end face 1b is formed on each side of the rectangular glass plate 1 so as to be substantially orthogonal to the main surface 1a.

The thickness of the glass plate 1 is preferably 0.4 mm or less, 0.3 mm or less, or 0.2 mm or less. It is more preferably 0.19 mm or less, still more preferably 0.15 mm or less, and particularly preferably 0.12 mm or less. On the other hand, the thickness of the glass plate 1 is preferably 0.05 mm or more, more preferably 0.08 mm or more.

The area of each main surface 1a in the glass plate 1 can be 1 mm ² or more and 25000 mm ² or less. The area of each main surface 1a is preferably 3 mm ² or more and 25000 mm ² or less, more preferably 9 mm ² or more and 25000 mm ² or less, still more preferably 15 mm ² or more and 25000 mm ² or less, and particularly preferably 20 mm ² or more and 25000 mm ^{2 or} less.

A plurality of crater-shaped recesses R are formed on the end surface 1b of the glass plate 1, as schematically shown in FIG. The outer periphery of the top of the recess R (the ridge line when the recesses R are adjacent to each other) C is, for example, circular or elliptical.

Among the recesses R included in an arbitrary 30 μm square range S of the end face 1b, the ratio of the first recesses R1 where the maximum value d of the linear distance between two points on the top outer periphery C is 0.5 μm or more is 50%. That's it. In other words, of the recesses R included in an arbitrary 30 μm square range S of the end face 1b, the maximum value d of the linear distance between two points on the top outer periphery C is less than 0.5 μm. shown) is less than 50%. Here, the maximum straight line distance d is the diameter when the recess R is circular, and the major axis when the recess R is elliptical. In this way, even if an external force such as an impact acts on the end surface 1b of the glass plate 1, the force can be appropriately dispersed by the relatively large first concave portion R1 formed on the end surface 1b. be done. As a result, cracks originating from the end face 1b of the glass plate 1 are less likely to develop, and breakage of the glass plate 1 can be reduced. It should be noted that the relatively small second concave portion cannot be expected to have the above-mentioned effect of dispersing the external force so much, and on the contrary, it may cause damage. Therefore, it is preferable to increase the proportion of the first recess R1 and decrease the proportion of the second recess. The ratio of the first concave portion R1 is preferably 85% or more, more preferably 90% or more.

The total number of recesses R included in any range S of 30 μm square of the end surface, that is, the total number of the first recesses R1 and the second recesses is preferably 30 or more and 300 or less. As the total number of recesses R decreases, the number of second recesses tends to decrease and the first recesses R1 tend to become more dominant. Therefore, considering this point, the total number of recesses R is preferably 300 or less, more preferably 150 or less. On the other hand, if the total number of recesses R is reduced more than necessary, the processing time in the etching process described later will be lengthened, resulting in poor production efficiency. Further, when the total number of recesses R is reduced to a certain extent, the breakage rate of the glass plate 1 may not change even if the total number of recesses R is further reduced. Therefore, considering these points, the total number of recesses R is preferably 30 or more, more preferably 50 or more.

As shown in FIG. 3, the depth h of the first concave portion R1 is preferably 0.5 μm or more, more preferably 1 μm or more. Here, the depth h is the height difference between the deepest position of the first recess R1 and the highest position on the top outer circumference C of the first recess R1. By doing so, it is considered that the first concave portion R1 becomes sufficiently deep, and the effect of dispersing the external force is exhibited more effectively. The depth h of the first concave portion R1 is preferably 10 μm or less, more preferably 5 μm or less.

The surface roughness Ra of the end surface 1b of the glass plate 1 is preferably 0.1 nm to 10 nm.

The glass plate 1 has a composition of 5 to 50% P ⁵⁺ , 2 to 30% Al ³⁺ , and R′ ⁺ (R′ is at least one selected from Li, Na and K) 10 to 10% in terms of cation %. 50% and R ²⁺ (R ²⁺ is at least one selected from Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , Ba ²⁺ and Zn ²⁺ ) 20-50%, Cu ²⁺ 0. It contains 5-15% and, expressed in % anion, 5-80% F ^- and 20-95% O ^2- .

In addition to the above composition, the glass plate 1 may have a composition containing 5 to 80% of F ⁻ in terms of % of anions.

The glass plate 1 is more preferably composed of 40 to 50% P ⁵⁺ , 7 to 12% Al ³⁺ , 15 to 25% K ⁺ 3 to 12% Mg ²⁺ , and Ca ² in terms of cation %. ⁺ 3-6%, Ba ²⁺ 7-12%, Cu ²⁺ 1-15% and, expressed in % anions, F ^- 5-80% and O ^2- 20-95% Glass can be used.

As the glass plate 1 having another preferable composition, P ⁵⁺ 20 to 35%, Al ³⁺ 10 to 20%, Li ⁺ 20 to 30%, Na ⁺ 0 to 10%, and Mg ²⁺ 1 are expressed in terms of cation %. ~8%, Ca ²⁺ 3-13%, Sr ²⁺ 2-12%, Ba ²⁺ 2-8%, Zn ²⁺ 0-5%, Cu ²⁺ 0.5-5% and anion percentage , a fluorophosphate glass containing 30-65% F ^- and 35-75% O ^2- can be used.

As the glass plate 1 having another preferable composition, P ⁵⁺ 35 to 45%, Al ³⁺ 8 to 12%, Li ⁺ 20 to 30%, Mg ²⁺ 1 to 5%, Ca ²⁺ in terms of cation %. A fluorophosphate glass containing 3 to 6% Ba ²⁺ 4 to 8% Cu ²⁺ 1 to 6% and, expressed in % anion, 10 to 20% F ⁻ and 75 to 95% O ²⁻ . can be used.

As the glass plate 1 having other preferred compositions, the following are expressed in terms of cation %: P ⁵⁺ 30-45%, Al ³⁺ 15-25%, Li ⁺ 1-5%, Na ⁺ 7-13%, K ⁺ 0.5%. 1-5%, Mg ²⁺ 1-8%, Ca ²⁺ 3-13%, Ba ²⁺ 6-12%, Zn ²⁺ 0-7%, Cu ²⁺ 1-5% and anion % , 30-45% F ^- and 50-70% O ^2- can be used.

Below, the example in case the glass plate 1 is a phosphate glass excellent in an infrared absorption function is shown.

It is desirable that the phosphate glass used for the glass plate 1 does not substantially contain F (fluorine). Here, "substantially free" means that fluorine may be contained in an amount of 0.1% or less by mass %.

As such a phosphate-based glass, for example, one containing 25% by mass or more of P ₂ O ₅ can be used. Specifically, in mass %, P ₂ O ₅ 25 to 60%, Al ₂ O ₃ 2 to 19%, RO (R is at least one selected from Mg, Ca, Sr and Ba) 5 to 45 %, 0-13% ZnO, 8-20% K ₂ O, 0-12% Na ₂ O, and 0.3-20% CuO, and substantially free of fluorine. can.

P ₂ O ₅ is a component that forms a glass skeleton. The content of P ₂ O ₅ is preferably 25-60%, more preferably 30-55%, and still more preferably 40-50% by mass. If the P ₂ O ₅ content is too low, vitrification may become unstable. On the other hand, if the content of P ₂ O ₅ is too high, the weather resistance tends to deteriorate.

Al ₂ O ₃ is a component that further improves weather resistance. The content of A1 ₂ O ₃ is preferably 2 to 19%, more preferably 2 to 15%, still more preferably 2.8 to 14.5%, particularly preferably 3% by mass. 0.5 to 14.0%. If the content of Al ₂ O ₃ is too low, weather resistance may not be sufficient. On the other hand, if the content of Al ₂ O ₃ is too high, the meltability may deteriorate and the melting temperature may rise. When the melting temperature rises, Cu ions are reduced and tend to shift from Cu ²⁺ to Cu ⁺ , which may make it difficult to obtain desired optical properties. Specifically, the light transmittance in the near-ultraviolet to visible region may be lowered, and the infrared absorption characteristics may be easily lowered.

RO (where R is at least one selected from Mg, Ca, Sr and Ba) is a component that improves weather resistance and meltability. The content of RO is preferably 5 to 45%, more preferably 7 to 40%, and still more preferably 10 to 35% by mass. If the RO content is too low, weather resistance and meltability may not be sufficient. On the other hand, if the RO content is too high, the stability of the glass tends to decrease, and crystals derived from the RO component tend to precipitate.

In addition, the preferable range of content of each component of RO is as follows.

MgO is a component that improves weather resistance. The content of MgO is preferably 0 to 15%, more preferably 0 to 7% by mass. If the content of MgO is too high, the stability of the glass tends to decrease.

CaO, like MgO, is a component that improves weather resistance. The content of CaO is preferably 0 to 15%, more preferably 0 to 7% by mass. If the CaO content is too high, the stability of the glass tends to decrease.

SrO, like MgO, is a component that improves weather resistance. The content of SrO is preferably 0 to 12%, more preferably 0 to 5% by mass. If the SrO content is too high, the stability of the glass tends to decrease.

BaO is a component that stabilizes glass and improves weather resistance. The content of BaO is preferably 1 to 30%, more preferably 2 to 27%, and still more preferably 3 to 25% by mass. If the BaO content is too low, the glass may not be sufficiently stabilized or the weather resistance may not be sufficiently improved. On the other hand, if the BaO content is too high, crystals derived from BaO may easily precipitate during molding.

ZnO is a component that improves the stability and weather resistance of glass. The content of ZnO is preferably 0 to 13%, more preferably 0 to 12%, and still more preferably 0 to 10% by mass. If the content of ZnO is too high, the meltability is lowered and the melting temperature is increased, and as a result, it may be difficult to obtain the desired optical properties. In addition, the stability of the glass is lowered, and crystals derived from the ZnO component may easily precipitate.

As described above, RO and ZnO have the effect of improving the stabilization of the glass, and the effect is easily obtained particularly when the _amount of _P2O5 is small.

The content ratio of P ₂ O ₅ to RO (P ₂ O ₅ /RO) is preferably 1.0 to 1.9, more preferably 1.2 to 1.8. If the ratio (P ₂ O ₅ /RO) is too small, the liquidus temperature becomes high, and devitrification caused by RO tends to precipitate in some cases. On the other hand, if the P ₂ O ₅ /RO ratio is too large, the weather resistance tends to deteriorate.

K ₂ O is a component that lowers the melting temperature. The content of K ₂ O is preferably 8-20%, more preferably 12.5-19.5% by mass. If the K ₂ O content is too low, the melting temperature will be too high, making it difficult to obtain the desired optical properties. On the other hand, if the content of K ₂ O is too high, crystals caused by K ₂ O tend to precipitate during molding, and vitrification may become unstable.

Na ₂ O, like K ₂ O, is also a component that lowers the melting temperature. The content of Na ₂ O is preferably 0 to 12%, more preferably 0 to 7% by mass. If the content of Na ₂ O is too high, vitrification may become unstable.

CuO is a component for absorbing near-infrared rays. The content of CuO is preferably 0.3 to 20%, more preferably 0.3 to 15%, and still more preferably 0.4 to 13% by mass. If the CuO content is too low, desired near-infrared absorption characteristics may not be obtained. On the other hand, if the content of CuO is too high, the light transmittance in the ultraviolet to visible range may tend to be lowered. Moreover, vitrification may become unstable. In addition, the content of CuO for obtaining desired optical properties is preferably adjusted appropriately depending on the plate thickness.

In addition to the above components, B ₂ O ₃ , Nb ₂ O ₅ , Y ₂ O ₃ , La ₂ O ₃ , Ta ₂ O ₅ , CeO ₂ or Sb ₂ O ₃ may be added to the extent that the effect of the present invention is not impaired. may be contained in Specifically, the content of each of these components is preferably 0 to 3%, more preferably 0 to 2% by mass.

By making the glass plate 1 to have the above composition, it is possible to achieve both higher light transmittance in the visible range and better light absorption characteristics in the infrared range. Specifically, the light transmittance at a wavelength of 400 nm is preferably 78% or more, more preferably 80% or more, and the light transmittance at a wavelength of 500 nm is preferably 83% or more, more preferably 85% or more. . On the other hand, the light transmittance at a wavelength of 700 nm is preferably 12% or less, more preferably 9% or less, and the light transmittance at a wavelength of 800 nm is preferably 5% or less, more preferably 3% or less.

The glass plate 1 having the composition described above is molded into a plate shape by molding methods such as casting, roll-out, down-draw, redraw, float, and overflow.

Next, a method for manufacturing the glass plate 1 according to the first embodiment will be described.

This manufacturing method includes an etching step of etching an end face 1b of a glass plate (original glass plate) 1 with an etchant E, as shown in FIG.

In the etching step, the glass plate 1 is immersed in an etching liquid E contained in an etching bath B. As shown in FIG.

As the etchant E, an alkaline detergent is used. This is because if the glass plate 1 is made of phosphate-based glass as described above, it has lower alkali resistance than other glass such as fluorophosphate-based glass. Alkaline detergents are not particularly limited, but for example, detergents containing alkaline components such as Na and K, surfactants such as triethanolamine, benzyl alcohol or glycol, and water or alcohol can be used.

As an alkaline component contained in the alkaline detergent, it is preferable that an alkaline salt of a chelating agent such as aminopolycarboxylic acid is included. Alkali salts of aminopolycarboxylic acids include sodium and potassium salts of diethylenetriaminepentaacetic acid, ethylenediaminetetraacetic acid, triethylenetetraaminehexaacetic acid, nitrilotriacetic acid, and the like. Among these, pentasodium diethylenetriaminepentaacetate, tetrasodium ethylenediaminetetraacetate, hexasodium triethylenetetraaminehexaacetate and trisodium nitrilotriacetate are preferably used, and pentasodium diethylenetriaminepentaacetate is particularly preferably used.

In the etching step, the etching time and other conditions are adjusted so that the thickness t1 removed in the plane direction by etching the end face 1b of the glass plate 1 is 1 μm or more. In this way, the end surface 1b of the glass plate 1 is sufficiently etched with the etching solution E made of an alkaline detergent, and the ratio of the first concave portions R1 in the end surface 1b after etching easily exceeds 50%. The removed thickness t1 is preferably 5 μm or more, more preferably 7 μm or more, and particularly preferably 10 μm or more. Here, the removed thickness t1 is obtained by comparing the size of the glass plate 1 before etching and the size of the glass plate 1 after etching, for example. Specifically, as shown in FIG. 5, the difference between the dimension L1 of one side of the glass plate 1 before etching (linear distance between the opposing end faces 1b) and the dimension L2 of the same side of the glass plate 1 after etching. Measure ΔL. Since removal by etching occurs on both opposing end faces 1b, the removal thickness t1 is obtained by ΔL/2.

According to the manufacturing method including the etching process as described above, it is possible to manufacture the glass plate 1 in which the ratio of the first concave portion R1 is 50% or more within an arbitrary range S of 30 μm square of the end surface.

(Second embodiment)
As shown in FIGS. 6 and 7, the glass plate 1 according to the second embodiment differs from the glass plate 1 according to the first embodiment in that optical films 2 are provided on both main surfaces 1a of the glass plate 1. It is a point formed respectively. Hereinafter, for convenience of explanation, the glass plate 1 having the optical film 2 formed on the main surface 1a thereof will be referred to as a glass plate 3 with an optical film. The optical film-coated glass plate 3 is used, for example, as a cover glass or a visibility correcting member for matching the spectral sensitivity of a solid-state imaging device to the characteristics of human visibility.

In the present embodiment, the optical film 2 has a protruding portion 2a that protrudes outward beyond the edge of the main surface 1a of the glass plate 1 . Note that the protruding portion 2a may not be provided.

The protruding portion 2 a extends outward along the main surface 1 a of the glass plate 1 , and the tip of the protruding portion 2 a is separated from the end surface 1 b of the glass plate 1 . It should be noted that the overhanging portion 2a does not necessarily have to be parallel to the main surface 1a of the glass plate 1, and may be inclined such that the tip hangs down. Also, a part of the base end portion of the overhanging portion 2a may be in contact with the end surface 1b of the glass plate 1.

The protruding portion 2a is formed in a frame shape so as to surround the entire circumference of the main surface 1a of the glass plate 1 (see the cross-hatched portion in FIG. 7).

A protrusion dimension t1 in the planar direction of the protrusion 2a is preferably 1 μm to 0.1 mm, more preferably 3 μm to 20 μm. With such a protruding dimension, the protruding portion 2a protrudes sufficiently outward, so that other members are unlikely to come into direct contact with the end face 1b of the glass plate 1, and the end face 1b of the glass plate 1 does not reach the end face 1b. dust generation and damage can be reduced.

The thickness of the optical film 2 is thinner than the thickness of the glass plate 1, preferably 10 μm or less. More preferably, it is 7 μm or less. On the other hand, the thickness of the optical film 2 is preferably 0.1 μm or more, more preferably 0.2 μm or more.

The optical film 2 is appropriately selected according to the application. For example, functional films such as an antireflection film (AR film), an infrared shielding film (IR cut film), an ultraviolet shielding film, and an ultraviolet and infrared shielding film are used. mentioned. Also, the optical film 2 may have the functions of both an antireflection film and an infrared shielding film. For the optical film 2 having such functions, for example, a dielectric multilayer film in which low refractive index layers and high refractive index layers are alternately laminated can be used. A silicon oxide film or the like is used as the low refractive index layer. As the high refractive index layer, a metal oxide film made of at least one selected from tantalum oxide, niobium oxide, titanium oxide, hafnium oxide, silicon nitride, and zirconium oxide is used. The optical film 2 formed on one main surface 1a of the glass plate 1 and the optical film 2 formed on the other main surface 1a of the glass plate 1 may be films having the same function. It may be membranes with different functions. Specifically, the configuration of the glass plate 3 with an optical film includes, for example, antireflection film/glass plate/antireflection film, antireflection film/glass plate/infrared shielding film, infrared shielding film/glass plate/infrared shielding film, Infrared shielding film/glass plate/ultraviolet and infrared shielding film.

With the optical film-coated glass plate 3 having the above structure, the optical film 2 is formed in a wider range than the main surface 1a of the glass plate 1 by the projecting portion 2a. Therefore, the optical film 2 can be reliably formed on the entire surface of the main surface 1a of the glass plate 1 including the vicinities of the edges.

Next, a method for manufacturing the optical film-coated glass plate 3 according to the second embodiment will be described.

This manufacturing method includes a film forming process, a cutting process, and an etching process in this order. In this embodiment, as shown in FIGS. 8 and 9, a plurality of product-sized glass plate laminates 6 are collected from an original glass plate laminate 5 including a large original glass plate 4, so-called multi-panel sampling. Give an example. Of course, one glass plate laminate 6 may be taken from the original glass plate laminate 5 for the purpose of trimming or the like. In this manufacturing method, the original glass plate laminate 5 →glass plate laminate 6 →glass plate 3 with an optical film are produced in this order.

As shown in FIG. 8 , in the film formation step, the optical films 2 are formed on both main surfaces 4 a of the original glass plate 4 to manufacture the original glass plate laminate 5 . The optical film 2 is formed on the entire main surface 4a of the original glass plate 4 . The optical film 2 is formed using, for example, a vacuum deposition method, a sputtering method, or the like.

As shown in FIG. 9 , in the cutting step, for example, the original glass plate laminate 5 is cut in a grid pattern to produce a plurality of glass plate laminates 6 . In the illustrated example, nine glass plate laminates 6 are collected from one original glass plate laminate 5 . The method of cutting the original glass plate laminate 5 is not particularly limited, but for example, mechanical cutting with a blade of a dicing machine, folding splitting, laser splitting, laser fusion cutting, or the like can be used.

As shown in FIG. 10, in the etching step, the glass plate laminate 6 is immersed in an etchant E contained in an etching bath (not shown).

The etchant E reacts with the glass plate 1 but does not substantially react with the optical film 2 . In the present embodiment, the glass plate 1 included in the glass plate laminate 6 has the optical films 2 formed on both main surfaces 1a. is in direct contact with the etchant E and reacts with it. Therefore, only the edge portion of the glass plate 1 is gradually eroded by the etchant E, and the position of the edge face 1b of the glass plate 1 moves in the A direction. As a result, only the surface layer portion X1 (cross-hatched portion in FIG. 10) at the edge of the glass plate 1 is removed while the optical film 2 remains as it was. Accordingly, as shown in FIG. 6, an optical-film-coated glass plate 3 having optical films 2 formed on both main surfaces 1a of the glass plate 1 and having protruding portions 2a is manufactured.

The removal thickness t3 in the plane direction by etching is preferably 1 μm to 0.1 mm, more preferably 3 μm to 20 μm. It is preferable that this removed thickness t3 substantially coincides with the overhang dimension t2 of the overhang portion 2a in FIG.

Here, in this manufacturing method, since both main surfaces 1a of the glass plate 1 are protected by the optical film 2 in the state of the glass plate laminate 6, the thickness of the glass plate 1 is not changed in the etching process. , the end surface of the glass plate 1 can be processed.

(Third embodiment)
As shown in FIG. 11, the glass plate 1 according to the third embodiment, like the second embodiment, relates to the glass plate 3 with an optical film, and is different from the glass plate 1 according to the second embodiment. is that the end face 1b of the glass plate 1 is chamfered.

An end surface 1b of the glass plate 1 has a chamfered portion 1c formed of an inclined plane inclined with respect to the main surface 1a in partial regions on both main surface 1a sides. The inclination angle θ of chamfered portion 1c with respect to main surface 1a is preferably 20° to 60°. The shape of the chamfered portion 1c is not particularly limited. Further, the entire end surface 1b of the glass plate 1 may be formed into a convex curved surface to provide a chamfered portion on the entire end surface 1b.

When the chamfered portion 1c is formed on the end surface 1b of the glass plate 1, the end surface 1b may have a portion Y (cross-hatched portion in FIG. 11) located outside the overhanging portion 2a of the optical film 2. . This makes it easier for other members to come into direct contact with the end surface 1b of the glass plate 1, but the mechanical strength of the end surface 1b is further improved by the chamfered portion 1c. Breakage can be reduced. Of course, the projecting portion Y may not be provided.

In this embodiment, a chamfered portion 2b is also formed at the tip of the protruding portion 2a of the optical film 2 . The shape of the chamfered portion 2b is not particularly limited, but a shape similar to that of the chamfered portion 1c of the glass plate 1 can be selected. Alternatively, the chamfered portion 2b of the optical film 2 may be omitted and only the chamfered portion 1c of the glass plate 1 may be provided.

A protrusion dimension t4 of the protrusion 2a in the planar direction is preferably 1 μm to 0.1 mm, more preferably 3 μm to 20 μm.

Next, a method for manufacturing the glass plate 3 with an optical film according to the third embodiment will be described.

This manufacturing method includes a film forming process, a cutting process, a chamfering process, and an etching process in this order. In this embodiment, the cutting step also serves as the chamfering step, and an example in which the original glass plate laminate 5 is also chamfered in the process of cutting is shown.

In the film forming step, the original glass plate laminate 5 is manufactured by the same method as in the second embodiment (see FIG. 8).

As shown in FIGS. 12 and 13, the cutting step is a first step of cutting the surface layer portion 5s of the original glass plate laminate 5 including the vicinity of the main surface 4a of the original glass plate 4 with the first blade P of the dicing device. and, as shown in FIG. 14, a second step of cutting the central portion 5c of the original glass plate laminate 5 left uncut in the first step with a second blade Q of a dicing device.

As shown in FIGS. 12 and 13, the first blade P is rotatably held in the shape of a disc, and has a cutting edge P1 on its peripheral edge. The cutting edge P1 has a pair of inclined surfaces P2 inclined in opposite directions to form a V-shaped convex portion.

As shown in FIG. 14, the second blade Q is also rotatably held in the shape of a disc, and has a cutting edge Q1 on its peripheral edge. The second blade Q is thinner than the first blade P. The shape of the cutting blade Q1 is not particularly limited as long as it is a shape capable of cutting the original glass plate laminate 5 within the range of the thickness of the second blade Q. In addition, instead of the second blade Q, cutting by laser irradiation may be used.

In the first step, first, as shown in FIG. 12, one surface layer portion 5s of the original glass plate laminate 5 is cut while rotating the first blade P to cut one surface layer portion 5s of the original glass plate laminate 5. A V-shaped groove 5a corresponding to the shape of the cutting edge P1 is formed in the . After that, as shown in FIG. 13, the original glass plate laminate 5 in which the grooves 5a are formed is turned upside down, and the other surface layer portion 5s of the original glass plate laminate 5 is cut while rotating the first blade P, A V-shaped groove 5a corresponding to the shape of the cutting blade P1 is also formed in the other surface layer portion 5s of the original glass plate laminate 5 . Next, in the second step, as shown in FIG. 14, the second blade Q is formed so as to connect the groove bottoms of the V-shaped grooves 5a formed in both surface layer portions 5s of the original glass plate laminate 5. is rotated, the central portion 5c of the original glass plate laminate 5 is cut, and the original glass plate laminate 5 is cut (full cut). As a result, the glass plate laminate 6 is produced from the original glass plate laminate 5, and the chamfered portions 1c and 2b are formed in the produced glass plate laminate 6 at portions corresponding to the V-shaped grooves 5a. be.

Of course, the chamfering process may be performed as a separate process after the cutting process is finished. In this case, as shown in FIG. 15, the chamfering process can be performed using a rotating grindstone W. As shown in FIG. Specifically, the grindstone W has a pair of conical processing surfaces W1 having opposite inclinations with respect to the thickness direction of the glass plate laminate 6 produced in the cutting step. The glass plate laminate 6 polished by the grindstone W is ground into a shape following the processing surface W1 of the grindstone W. As shown in FIG. That is, chamfered portions 1c and 2b are formed on the end surfaces of the glass plate 1 and the optical film 2 at positions polished by the processing surface W1. The chamfering step includes a first step of forming chamfered portions 1c and 2b on the end face of glass plate 1 on the side of one main surface 1a, and a first step of forming chamfered portions 1c and 2b on the end face of glass plate 1 on the other main surface 1a side. You may divide|segment into the 2nd process of forming.

As shown in FIG. 16, the glass plate laminate 6 having the chamfered portions 1c and 2b is immersed in an etchant E in the etching step. Then, only the end portion of the glass plate 1 that is in direct contact with the etchant E is gradually eroded, and the position of the end face 1b of the glass plate 1 moves in the A direction. As a result, the surface layer portion X2 (cross-hatched portion in the figure) at the end portion of the glass plate 1 is removed while the optical film 2 remains as it is. At this time, although the position of the end face 1b changes, the shape of the end face 1b is generally maintained. Therefore, the chamfered portion 1c of the glass plate 1 remains even after the etching process. In addition, since the optical film 2 does not react with the etchant E, the chamfered portion 2b of the optical film 2 remains after the etching process. Accordingly, as shown in FIG. 11, an optical film 2 having protruding portions 2a is formed on both main surfaces 1a of the glass plate 1, and chamfered portions 1c and 2b are formed on the glass plate 1 and the optical film 2. The optical film-coated glass plate 3 thus obtained is manufactured.

The removal thickness t5 in the plane direction by etching is preferably 1 μm to 0.1 mm, more preferably 3 μm to 20 μm. It is preferable that this removed thickness t5 substantially coincides with the overhang dimension t4 of the overhang portion 2a in FIG.

(Fourth embodiment)
As shown in FIG. 17, the glass plate 1 according to the fourth embodiment relates to the optical film-attached glass plate 3, similarly to the second and third embodiments, and the glass according to the second and third embodiments. The difference from plate 1 is that optical film 2 is formed only on one main surface 1a of glass plate 1 .

Although the optical film 2 has the protruding portion 2a in this embodiment, the protruding portion 2a may not be provided. A protrusion dimension t6 of the protrusion 2a in the planar direction is preferably 1 μm to 0.1 mm, more preferably 3 μm to 20 μm. In the illustrated example, the chamfered portion is not provided, but the chamfered portion described in the third embodiment may be provided.

The manufacturing method of the optical film-coated glass plate 3 configured as described above includes a film forming process, a cutting process, and an etching process in this order.

As shown in FIG. 18 , in the film formation step, the optical film 2 is formed only on one main surface 4 a of the original glass plate 4 to manufacture the original glass plate laminate 5 . The optical film 2 is formed all over one main surface 4 a of the original glass plate 4 .

In the cutting step, one or a plurality of glass plate laminates 6 are manufactured from the original glass plate laminate 5 by the same method as in the second embodiment (see FIG. 9). However, in the manufactured glass plate laminate 6 , the optical film 2 is formed only on one main surface 1 a of the glass plate 1 .

As shown in FIG. 19, the glass plate laminate 6 is immersed in an etchant E in the etching step. As a result, the edge of the glass plate 1 directly contacting the etchant E and the main surface 1a on the side where the optical film 2 is not formed are gradually eroded, and the end surface 1b of the glass plate 1 moves in the direction A. , the main surface 1a of the glass plate 1 moves in the B direction. As a result, the surface layer portion X3 (cross-hatched portion in the figure) of the edge portion of the glass plate 1 and the surface layer portion X4 (cross-hatched portion in the figure) of the main surface 1a are removed while the optical film 2 remains as it is. be done. Accordingly, as shown in FIG. 17, an optical-film-coated glass plate 3 having an optical film 2 having an overhanging portion 2a only on one main surface 1a of the glass plate 1 is manufactured.

The removal thickness t7 in the plane direction by etching is preferably 1 μm to 0.1 mm, more preferably 3 μm to 20 μm. It is preferable that this removed thickness t7 substantially coincides with the overhang dimension t6 of the overhang portion 2a in FIG. Also, the thickness t8 removed in the plate thickness direction by etching is preferably 1 μm to 0.1 mm, more preferably 3 μm to 20 μm.

Here, in this manufacturing method, since only one main surface 1a of the glass plate 1 is protected by the optical film 2, the thickness of the glass plate 1 changes in the etching process. Therefore, in addition to processing the end surface of the glass plate 1, slimming processing (thinning) of the glass plate 1 can be performed.

The relationship between the amount of removal by etching of the edge face of the glass plate and the recess formed in the edge face of the glass plate by etching is shown.

First, microscopic images were used to examine how the recesses formed on the edge surface of the glass plate by etching changed when the removal amount by etching was changed.

A glass plate made of phosphate glass containing 25% by mass or more of P ₂ O ₅ is prepared, and an infrared reflective film is formed as an optical film on both main surfaces of the glass plate. After that, the glass plate on which the optical film was formed was immersed in an alkaline detergent (etching solution) containing an alkali salt of a chelating agent to carry out an etching process. The etching time was set so that the thickness of the edge of the glass plate removed by etching was 1 μm or more. 20 and 21 show microscopic images of the edge face of the etched glass plate at this time. FIG. 20 shows the case where the removal thickness is small, that is, the etching time is short, and FIG. 21 shows the case that the removal thickness is large, that is, the etching time is long. As can be seen from these figures, it can be confirmed that as the removal thickness increases, more relatively large recesses (first recesses) are formed and the total number of recesses decreases.

Next, sample No. 2, which is a glass plate having infrared absorbing films formed on both main surfaces, was prepared. 1 to No. 6 was prepared, and it was examined how the size and number of recesses formed on the end surface of the glass plate by etching changed when the removal amount by etching was changed. In addition, the glass plate was subjected to a drop test to examine the breakage rate, and the sample No. For 6, the average depth of the recess was also examined. Table 1 shows the results. The size and number of recesses were measured within a range of 30 μm square on the end surface of the glass plate. The drop test was carried out on sample no. 1 to No. For each of 6, 10 samples prepared under the same conditions are housed inside a tray with a lid, and the tray with a lid is held parallel to the floor at a height of 2 m from the concrete floor. It was performed by free-falling from the floor to the floor. The breakage rate is the number of samples broken inside the lidded tray at this time, expressed as a percentage. A tray with a lid, as disclosed in JP-A-2016-78860, supports the sample in point contact with projections provided on the tray and the lid (corresponding to the mounting portion and the contact portion in the same document). Together with this, the one in which the housing space for each sample was partitioned by ribs was used. Even if an optical film such as an infrared absorbing film is not formed on the main surface of the glass plate, the total number of recesses, the ratio of the first recesses to the second recesses, the breakage rate, etc. do not change significantly.

As shown in Table 1, sample no. When etching was not performed and the ratio of the glass first concave portions was very small, as in No. 1, the breakage rate of the glass plates was 100% (10 out of 10 glass plates were broken). On the other hand, sample no. 2 to No. As shown in 6, it can be confirmed that the breakage rate of the glass plate is reduced when the edge face of the glass plate is removed by etching by 1 μm or more and the ratio of the first concave portions is 50% or more. In particular, sample no. 4 to No. 6, it can be confirmed that the breakage rate of the glass plate is greatly improved when the ratio of the first concave portions is 85% or more.

In addition, the present invention is not limited to the configuration of the above-described embodiment, nor is it limited to the above-described effects. Various modifications can be made to the present invention without departing from the gist of the present invention.

In the above embodiment, in the etching process, the state in which the entire glass plate is immersed in the etchant is illustrated and explained. , only a part of the glass plate may be etched.

In the above embodiment, when the optical film is formed, the removal thickness in the plane direction by etching may be measured from the protruding dimension of the protruding portion of the optical film.

In the above embodiment, the film forming process is performed before the cutting process, but the film forming process may be performed after the cutting process (or after the chamfering process when the chamfering process is performed).

In the above embodiment, the cutting step may be omitted, and the optical film may be directly formed on the product-sized glass plate in the film forming step.

In the above embodiment, the optical film may be removed from the main surface of the glass plate after the etching step.

In the above embodiment, in the cutting step, the cut portion of the original glass plate laminate may be cut by laser fusion by irradiating the cut portion with a laser while injecting gas. In this case, by adjusting the injection amount and injection direction of the gas, the cut end face can be processed into a convex curved surface (for example, an arcuate surface). Therefore, even if such laser fusion cutting is used, chamfering can be performed at the same time as cutting.

1 glass plate 1a main surface 1b end face 1c chamfered portion 2 optical film 2a protruding portion 2b chamfered portion 3 glass plate with optical film 4 original glass plate 5 original glass plate laminate 6 glass plate laminate R concave portion R1 first concave portion C Top circumference E of recess Etching liquid P First blade Q Second blade W Grindstone

Claims (9)

A glass plate having a pair of front and back main surfaces and end faces connecting the ends of the pair of main surfaces,
The glass plate contains, in mass%, P ₂ O ₅ 25 to 60%, Al ₂ O ₃ 2 to 19%, RO (wherein R is at least one selected from Mg, Ca, Sr and Ba) 5 to 45 %, ZnO 0 to 13%, K ₂ O 8 to 20%, Na ₂ O 0 to 12%, and CuO 0.3 to 20%, and the content of the fluorine component is 0.1% by mass or less. made of phosphate-based glass ,
The end surface has a plurality of crater-shaped recesses,
Among the recesses included in an arbitrary 30 μm square range of the end face, the ratio of the first recesses where the maximum value of the linear distance between two points on the outer periphery of the top is 0.5 μm or more is 50% or more. A glass plate characterized by: 2. The glass plate according to claim 1, wherein the total number of said recesses included in an arbitrary range of 30 [mu]m square of said end face is 30 or more and 300 or less. 3. The glass plate according to claim 1, wherein the depth of said first concave portion is 0.5 [mu]m or more. 4. The glass plate according to any one of claims 1 to 3, wherein an optical film is formed on at least one of said main surfaces. 5. The glass plate according to claim 4, wherein the optical film is at least one of an antireflection film, an infrared shielding film, an ultraviolet shielding film, and an ultraviolet and infrared shielding film. 6. The glass plate according to any one of claims 1 to 5, wherein the glass plate contains 25% or more of P ₂ O ₅ in terms of mass% as a composition. In a method for manufacturing a glass plate having a pair of front and back main surfaces and end faces connecting ends of the pair of main surfaces,
An etching step of etching by bringing at least the end face of the glass plate into contact with an etchant,
The glass plate contains, in mass%, P ₂ O ₅ 25 to 60%, Al ₂ O ₃ 2 to 19%, RO (wherein R is at least one selected from Mg, Ca, Sr and Ba) 5 to 45 %, ZnO 0 to 13%, K ₂ O 8 to 20%, Na ₂ O 0 to 12%, and CuO 0.3 to 20%, and the content of the fluorine component is 0.1% by mass or less. made of phosphate-based glass ,
The etchant is an alkaline detergent,
A method for manufacturing a glass plate, wherein a thickness removed by the etchant from the end surface of the glass plate is 1 μm or more. 8. The method for manufacturing a glass plate according to claim 7, wherein the etching liquid contains an alkali salt of a chelating agent as an alkali component. 9. The method of manufacturing a glass plate according to claim 7, further comprising a film forming step of forming an optical film on at least one main surface of the glass plate before the etching step.

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