JP5516442B2 - Method for manufacturing cover glass for display device - Google Patents

Description

  The present invention relates to a method of manufacturing a cover glass for a display device that covers the entire surface of an image display portion.

  Conventionally, in a display device, a plate-like cover glass is disposed on the front surface of the display device so as to be a wider area than the image display portion (for example, Patent Document 1).

  This cover glass for a display device includes a shape processing step of chamfering a glass edge after cutting a base plate and processing the glass plate into a predetermined shape, and a cleaning step of cleaning the glass plate processed into a predetermined shape And a chemical strengthening step of chemically strengthening the cleaned glass plate, and having a desired impact resistance performance.

  Conventionally, the glass plate cleaning process is performed by using a roll brush or disk brush with a large tip reaction force to remove dirt such as organic and inorganic substances adhering to the processed glass plate and foreign matters such as fine glass pieces and dust. The main surface of the plate was cleaned in physical contact.

JP 2010-169788 A

  However, in recent years, the cover glass for display devices tends to be made thinner, that is, the glass strength tends to decrease, and the strength required in the conventional manufacturing method cannot be easily obtained even by chemical strengthening treatment. I had to assume that the plate would break. Therefore, a protective film as an enclosure is essential, but the use of a protective film is not preferable because it increases the number of parts and processes.

  An object of this invention is to provide the cover glass for display apparatuses which is hard to be broken even if it makes it thin.

（３）ディスプレイ装置用ガラスの素板から所定の形状のガラス板に加工する形状加工工程と、前記ガラス板を洗浄する洗浄工程と、前記洗浄したガラス板に化学強化を行なう化学強化工程と、を備えるディスプレイ装置用カバーガラスの製造方法であって、
前記洗浄工程では、前記ガラス板の少なくとも一方の主表面にロールブラシの先端を当接させることで前記ガラス板が洗浄され、
前記ロールブラシを構成するブラシ線の長さをＬ（ｍｍ）、線径をｄ（ｍｍ）、ヤング率をＥ（Ｐａ）、たわみを１ｍｍとしたときの下記（Ａ）式で表わされるブラシ先端反力Ｐ１がＰ１≦０．４０Ｎであることを特徴とするディスプレイ装置用カバーガラスの製造方法。

（４）ブラシ先端反力Ｐ１が、Ｐ１≦０．４０Ｎとなるロールブラシを用いて、化学強化後のガラス板の前記少なくとも一方の主表面にロールブラシの先端を当接させることで、前記化学強化後のガラス板を洗浄することを特徴とする（２）又は（３）に記載のディスプレイ装置用カバーガラスの製造方法。
（５）前記ガラス板の厚みが、０．５ｍｍ〜２．０ｍｍであることを特徴とする（１）〜（４）のいずれかに記載のディスプレイ装置用カバーガラスの製造方法。 The present invention provides the following aspects.
(1) A shape processing step of processing a glass plate for a display device into a glass plate of a predetermined shape, a cleaning step of cleaning the glass plate, a chemical strengthening step of chemically strengthening the cleaned glass plate, A method for producing a cover glass for a display device comprising:
In the cleaning step, a tip of a roll brush is placed on at least one main surface of the glass plate so that a BOR (Ball on Ring) strength of the glass plate before the chemical strengthening step is 400 N or more after the cleaning step. A method of manufacturing a cover glass for a display device, wherein the glass plate is washed by contact.
(2) The length of the brush wire constituting the roll brush is L (mm), the wire diameter is d (mm), the Young's modulus is E (Pa), and the deflection is 1 mm. The method for producing a cover glass for a display device according to (1), wherein the brush tip reaction force P1 is P1 ≦ 0.40N.

(3) a shape processing step for processing a glass plate for a display device into a glass plate of a predetermined shape, a cleaning step for cleaning the glass plate, a chemical strengthening step for chemically strengthening the cleaned glass plate, A method for producing a cover glass for a display device comprising:
In the cleaning step, the glass plate is cleaned by bringing the tip of a roll brush into contact with at least one main surface of the glass plate,
Brush tip represented by the following formula (A) when the length of the brush wire constituting the roll brush is L (mm), the wire diameter is d (mm), the Young's modulus is E (Pa), and the deflection is 1 mm. Reaction force P1 is P1 ≦ 0.40N, The manufacturing method of the cover glass for display apparatuses characterized by the above-mentioned.

(4) The tip of the roll brush is brought into contact with the at least one main surface of the chemically strengthened glass plate using a roll brush having a brush tip reaction force P1 satisfying P1 ≦ 0.40N. The method for producing a cover glass for a display device according to (2) or (3), wherein the tempered glass plate is washed.
(5) The method for producing a cover glass for a display device according to any one of (1) to (4), wherein the glass plate has a thickness of 0.5 mm to 2.0 mm.

  As a result of intensive studies, the inventors of the present invention have found that the glass plate having a low strength before chemical strengthening is a US60065 standard known as a safety standard applied to electrical appliances used in the United States even if chemical strengthening is performed. The standard value (2J) was not satisfied without the protective film, and the strength of the glass plate after chemical strengthening was found to be affected by the strength of the glass plate before chemical strengthening. And based on the knowledge, trial and error were repeated so as to satisfy the standard value of the US60065 standard even without a protective film, and the present invention was achieved.

  According to the cover glass for a display device according to (1) of the present invention, in the cleaning step before the chemical strengthening step, the glass plate is cleaned with a roll brush so that the BOR strength of the glass base plate is 400 N or more. The glass plate after chemical strengthening can have a desired impact resistance performance. The UL 60065 standard is known as a safety standard applied to electrical appliances used in the United States, but it is protected by cleaning the glass plate with a roll brush so that the BOR strength of the glass base plate is 400 N or more. Even without using a film, it is possible to satisfy 2J, which is the reference value of the UL60065 standard for the cover glass for display device after chemical strengthening.

  According to the cover glass for a display device according to (2) of the present invention, the length, alignment, and material of the roll brush are appropriately selected, and a glass plate is used using a roll brush having a brush tip reaction force P1 of 0.40 N or less. Can satisfy 2J, which is the reference value of UL60065 standard for display device cover glass after chemical strengthening.

  According to the cover glass for a display device according to (3) of the present invention, the length, alignment, and material of the roll brush are appropriately selected, and a glass plate is used using a roll brush having a brush tip reaction force P1 of 0.40 N or less. By washing, it is possible to satisfy 2J, which is the reference value of the UL60065 standard for the display device cover glass after chemical strengthening without using a protective film.

  According to the cover glass for a display device according to (4) of the present invention, a roll brush whose brush tip reaction force P1 is equal to or less than a predetermined value is used even if it is a glass plate after chemical strengthening, as before chemical strengthening. By washing the glass plate, the glass plate after chemical strengthening can maintain desired impact resistance.

  According to the cover glass for a display device as described in (5) of the present invention, it is possible to effectively realize both thinning and impact resistance.

It is sectional drawing of the display apparatus with which the cover glass for display apparatuses of one Embodiment of this invention is arrange | positioned. It is a flowchart of the manufacturing method of the cover glass for display apparatuses. It is a schematic diagram of a washing | cleaning apparatus. It is a mimetic diagram at the time of glass plate washing for explaining a brush tip reaction force. It is a schematic diagram of a brush evaluation machine. It is a graph which shows the relationship between the breaking load (BOR minimum strength) by the Ball on Ring test method of the glass plate before chemical strengthening, and the falling ball impact strength (falling ball minimum strength) after chemical strengthening. It is a graph which shows the relationship between the brush tip reaction force (P1) and the breaking load (BOR minimum strength) by the Ball on Ring test method of the glass plate before chemical strengthening.

  Hereinafter, the manufacturing method of the cover glass for display apparatuses of this invention is demonstrated. FIG. 1 is a cross-sectional view of a display device in which a cover glass for a display device according to an embodiment of the present invention is arranged.

  First, an embodiment of a display device using the cover glass for a display device of the present invention (hereinafter sometimes simply referred to as a cover glass) will be described with reference to FIG. In the following description, front, rear, left and right are based on the direction of the arrow in the figure.

  As shown in FIG. 1, the display device 40 includes a display panel 20 that is generally provided in a housing 45, and a cover glass 30 that covers the entire surface of the display panel 20 and is disposed in front of the housing 45.

  The cover glass 30 is installed mainly for the purpose of improving the aesthetics and strength of the display device 40, preventing impact damage, and the like. For example, a single sheet glass having a thickness of 0.5 to 2.0 mm. It is. If the glass is too thin, the strength may be lowered. Conversely, if the glass is too thick, the display becomes heavy, so 0.5 to 2.0 mm is preferable, and 0.6 to 1.9 mm is more. Preferably, 0.7 to 1.8 mm is more preferable, and 0.8 to 1.5 mm is most preferable. As shown in FIG. 1, the cover glass 30 may be installed so as to be separated from the display side (front side) of the display panel 20 (having an air layer), and has a translucent adhesive film (FIG. (Not shown) may be attached to the display side of the display panel 20.

  The cover glass 30 is provided with a functional film 41 on the front surface from which light from the display panel 20 is emitted, and a functional film 42 is provided at a position corresponding to the display panel 20 on the back surface from which light from the display panel 20 is incident. ing. In addition, although the functional films 41 and 42 are provided on both surfaces in FIG. 1, the functional films 41 and 42 are not limited to this and may be provided on the front surface or the back surface, or may be omitted.

  The functional films 41 and 42 have functions such as anti-reflection of ambient light, prevention of impact breakage, electromagnetic wave shielding, near-infrared shielding, color tone correction, and / or scratch resistance improvement, and thickness and shape are used for applications. It is selected as appropriate. The functional films 41 and 42 are formed by, for example, attaching a resin film to the cover glass 30 or may be formed by a thin film forming method such as a vapor deposition method, a sputtering method, or a CVD method.

  In addition, a black layer 44 is provided in a substantially frame shape on the entire periphery in a region outside the display panel 20 on the back surface of the cover glass 30. The black layer 44 is, for example, a coating formed by applying ink containing pigment particles to the cover glass 30, irradiating it with ultraviolet rays, or heating and baking it, and then cooling it. The panel 20 and the like become invisible, improving the aesthetics of the appearance.

As this cover glass 30 for display apparatuses, the glass of the following compositions is used, for example.
(I) 50% to 80% of SiO ₂ , ₂ to 25% of Al ₂ O ₃ , 0 to 10% of Li ₂ O, 0 to 18% of Na ₂ O, K ₂ O with a composition expressed in mol% Is represented by a glass (ii) mol% containing 0-10% MgO, 0-15% MgO, 0-5% CaO and 0-5% ZrO ₂ , SiO ₂ 50-74%, Al ₂ O ₃ and 1-10% 6-14% of Na ₂ O, _{K 2} O 3-11% of MgO 2 to 15% of CaO Less than six% and ZrO ₂ to contain 0-5% The total content of SiO ₂ and Al ₂ O ₃ is 75% or less, the total content of Na ₂ O and K ₂ O is 12 to 25%, and the total content of MgO and CaO is 7 to 15%. a composition which is displayed at a certain glass (iii) mol%, a SiO ₂ 68 to 80%, the _Al 2 _{O 3} 4 to 10%, a ₂ O and 5 to 15%, _{K 2} O 0 to 1%, the MgO 4 to 15% and ZrO ₂ is composition displaying a glass (iv) mole% containing 0 to 1%, a SiO ₂ 67 75%, the _Al 2 _{O 3} 0 to 4%, a Na ₂ O 7 to 15%, the _{K 2} O 1 to 9%, the MgO having 6 to 14% and the ZrO ₂ contained 0 to 1.5% The total content of SiO ₂ and Al ₂ O ₃ is 71 to 75%, the total content of Na ₂ O and K ₂ O is 12 to 20%, and when CaO is contained, the content is 1% Glass that is less than

  Next, the manufacturing method of the cover glass 30 for display apparatuses is demonstrated. FIG. 2 is a flowchart of a method for manufacturing a panel glass for panel display.

  As shown in FIG. 2, the manufacturing method of the cover glass 30 generally includes a shape processing step (S1), a first cleaning step (S2), a chemical strengthening step (S3), a second cleaning step (S4), And a printing step (S5).

  The shape processing step (S1) is a process of cutting a base plate obtained by mixing glass raw materials and melting in a float bath into a predetermined shape, typically a rectangular shape, and the first cleaning step (S2) is predetermined. This is a process of cleaning the glass plate cut out in the shape of, and details will be described later. The chemical strengthening step (S3) is a process of chemically strengthening the cleaned glass plate. The second cleaning step (S4) is a process of cleaning the chemically strengthened glass plate. The printing step (S5) is a process for forming the functional films 41 and 42 and the black layer 44. The shape processing step (S1), the chemical strengthening step (S3), the second cleaning step (S4), and the printing step (S5) employ known methods. Hereinafter, the first cleaning step is a feature of the present invention. (S2) will be described in detail.

  In the first cleaning step (S2), as shown in FIG. 3, a glass plate G is horizontally placed on a cleaning device 1 having a plurality of conveying rollers 11 on the lower side and a roll brush 12 on the upper side. The glass plate G is cleaned by bringing the rotating brush 12 into contact with the upper surface, which is one main surface of the glass plate G, while the lower surface of G is brought into contact with the conveying roller 11 to convey the glass plate G. To do. Normally, the glass plate G is cleaned by bringing the tip of the rotating brush 12 into contact with both surfaces of the glass plate G, and the both surfaces are cleaned. Further, the cleaning is performed while spraying water sprayed from the injection port 13 or neutral, alkaline or acidic liquid (hereinafter, a fluid sprayed on the glass plate is simply referred to as a cleaning liquid). As a result, foreign matters such as fine glass pieces and dust adhering to the glass plate G can be eliminated.

  In the roll brush 12, a plurality of brush wires 12b are typically attached to a cylindrical core member 12a made of metal (for example, SUS) or a resin in a spiral shape over the entire circumference of the core member 12a.

  Here, in the first cleaning step (S2) of the present invention, a roll brush is brought into contact with at least one main surface of the glass plate, and the Ball on Ring method of the glass plate before the chemical strengthening step (S3) (for details) The glass plate is washed so that the strength (BOR strength) according to (described later) is 400 N or more. BOR intensity represents the BOR minimum intensity. This is because even if the BOR maximum strength and the BOR average strength satisfy the reference value, the reliability of the product is inferior if the minimum strength is lower than the reference value.

  Moreover, in order to wash the glass plate so that the BOR minimum strength before chemical strengthening of the glass plate is 400 N or more, using a roll brush whose brush tip reaction force P1 described later is 0.40 N or less, It is preferable to clean the glass plate by bringing the tip of the roll brush into contact with at least one main surface.

The brush tip reaction force will be described below.
Focusing on one brush wire 12b constituting the roll brush 12, as shown in FIG. 4, the reaction force P (brush tip reaction force) is applied to the tip of the brush wire 12b in the opposite direction to the conveying direction of the glass sheet G. Works. At this time, the deflection of the brush wire 12b is δ (mm), the Young's modulus of the brush wire 12b is E (Pa), the cross-sectional secondary moment of the brush wire 12b is I (mm ⁴ ), and the length of the brush wire 12b is L ( mm), the deflection δ of the brush tip is expressed by the following formula (1) by double integration of the bending moment M.

  Further, the brush wire 12b has a circular cross section, and when the diameter (hereinafter also referred to as a wire diameter) is d (mm), the cross sectional secondary moment I is expressed by the following equation (2).

  From the above equations (1) and (2), the brush tip reaction force P (N) is expressed by the following equation (3).

  In the present invention, the brush tip reaction force represented by the following equation (4) when the deflection δ of the brush wire 12b in the equation (3) is 1 mm is P1.

Examples of the present invention will be described below.
First, the present inventors examined the relationship between the falling ball impact strength after chemical strengthening, which is the standard of the US60065 standard, and the breaking load before chemical strengthening.

First, the SiO ₂ 64.5% by mol.%, _Al 2 _{O 3} of 6%, 12% of Na ₂ O, the _{K 2} O 4% composition containing MgO 11% and ZrO ₂ 2.5% Were processed into a size of 300 × 400 × 1.1 mm to prepare five test samples. Five test samples were washed so that the BOR minimum strength before chemical strengthening was different, then cut into 50 × 50 × 1.1 mm glass plates, and the breaking load was measured before chemical strengthening. The measurement method of the breaking load was the Ball on Ring method.

  The Ball on Ring method is introduced in, for example, ASTM Standard F-394 and the like, but in the present invention, measurement was performed by the following method. Ring is made of SUS304 having a diameter of 30 mm, Ball is made of SUS304 (material) having a diameter of 10 mm, and both are mirror-polished. The load speed was 1 mm / min. Place the glass plate on the Ring so that one main surface of the glass is on the lower side, and lower the Ball at a predetermined load speed using the A & D Tensilon Universal Tester RTC. Then, a load was applied to the glass plate, and the load (F) when the glass plate was broken was measured. It was confirmed that the breaking point of the glass was a position just below the contact point of Ball on the lower surface of the plate glass. The above Ball on Ring test was performed 30 times under one condition, and the one that was broken at the lowest load was defined as the minimum strength.

Moreover, the glass was immersed in a KNO ₃ chemical strengthening solution at 450 ° C. for 2 hours in what was washed under the same conditions as these five samples, and chemical strengthening was performed with a surface compressive stress of 800 MPa and an ion exchange depth of 30 μm. And the falling ball impact strength was measured. The falling ball impact strength was measured according to the UL 60065 standard. For the falling ball impact strength, the lowest falling ball strength was selected in consideration of reliability. The above-mentioned ball drop impact test was performed 20 times under one condition, and the one that was destroyed with the lowest impact energy was defined as the minimum strength.
The results are shown in Table 1 and FIG.

  The UL 60065 standard is known as a safety standard applied to electrical appliances used in the United States, but the UL 60065 standard requires the falling ball minimum strength to be 2 J or more. From the results of Table 1 and FIG. 6, when the minimum BOR strength before chemical strengthening is 348 N or more, the falling ball minimum strength after chemical strengthening satisfies 2J or more. However, in the present invention, the linearity of the obtained results In consideration of the above, BOR minimum strength 400N before chemical strengthening was made a critical value so that the falling ball minimum strength would surely be 2 J or more. As a result, it was confirmed that if the minimum BOR strength before chemical strengthening is 400 N or more, 2J, which is the standard value of the UL60065 standard for display device cover glass after chemical strengthening, is used without using a protective film. .

Subsequently, the present inventors examined the relationship between the breaking load before chemical strengthening and the brush tip reaction force P1.
First, five types of roll brushes shown in Table 1 with different wire diameters, wire lengths, and materials were prepared, and the brush tip reaction force P1 of these roll brushes was calculated. The calculation results are shown in Table 2.

Moreover, the measurement of the breaking load of the sample cleaned with the brush evaluation machine using the brushes of Examples 1 to 3 and Comparative Examples 1 and 2 was performed before chemical strengthening. First, in mol% _{SiO 2 64.5%, Al 2 O} 3 of 6%, 12% of Na ₂ O, the _{K 2} O 4%, MgO 11% and a composition comprising a ZrO ₂ 2.5% The glass was processed into a size of 300 × 400 × 1.1 mm to prepare a test sample. FIG. 5 is a schematic diagram of a brush evaluation machine. In FIG. 5, the same or corresponding components of the cleaning apparatus of FIG. 3 are described with the same or equivalent reference numerals for simplicity.

  As shown in FIG. 5, the brush evaluator 10 is provided with a plurality of transport rollers 11 below the transport path of the glass plate G, and a roll brush 12 that is rotatable by a driving device 14 above. The upper surface of the glass plate G placed horizontally on the conveyance path is configured to be cleaned by coming into contact with the tip of the rotating roll brush 12. Further, an injection port 13 is provided above the transport path, and the cleaning liquid stored in the tank 15 is pumped up by the pump 16 from the transport path and circulates through the filter 17 while spraying the cleaning liquid. The glass plate G is cleaned. Note that the measurement was performed with the conveyance roller 11 of the brush evaluation machine 10 stopped and the glass plate G fixed. Evaluation was performed with the outer diameter of the brush being 115 mm, the brush being pushed into the glass by 1 mm, the rotation speed of the brush being 66 rpm, the washing time being 60 seconds, and the washing water being ion-exchanged water.

After washing the test samples of Examples and Comparative Examples, they were cut into glass plates of 50 × 50 × 1.1 mm, and the breaking load was measured before chemical strengthening. The measurement method of the breaking load was the Ball on Ring method as described above. Ring is made of SUS304 having a diameter of 30 mm, Ball is made of SUS304 (material) having a diameter of 10 mm, and both are mirror-polished. The load speed was 1 mm / min. Place the glass plate on the Ring so that one main surface of the glass is on the lower side, and lower the Ball at a predetermined load speed using the A & D Tensilon Universal Tester RTC. Then, a load was applied to the glass plate, and the load (F) when the glass plate was broken was measured. It was confirmed that the breaking point of the glass was a position just below the contact point of Ball on the lower surface of the plate glass. The above Ball on Ring test was performed 30 times under one condition. Among them, the one that was broken at the lowest load was the lowest strength, the average value was the average strength, and the one that was broken at the highest load was the maximum strength.
Table 3 shows the measurement results of the breaking load.

  FIG. 7 is a graph showing the relationship between the brush tip reaction force P1 and the breaking load (BOR minimum strength) of the plate glass before chemical strengthening. The BOR average intensity is the average intensity when measured 30 times. Here, the BOR minimum strength is used as a reference in consideration of reliability.

  As apparent from Table 3 and FIG. 7, the BOR minimum strength of the samples cleaned with the brushes of Examples 1 and 2 showed the BOR minimum strength closest to the glass base plate not cleaned. In addition, compared with Example 2, the direction of Example 1 which lengthened the line length of the brush wire becomes smaller in rigidity, and the BOR minimum strength is higher. Moreover, the BOR minimum intensity | strength of the sample wash | cleaned with the brush of Example 3 also showed BOR average intensity | strength of 400 N or more. However, the rigidity of Example 3 in which the wire diameter of the brush wire is 2.5 times that of Example 1 is higher, and the BOR minimum strength is lower. The samples cleaned with the brushes of Comparative Examples 1 and 2 had a low BOR minimum strength of less than 400N.

From the two measurements described above, the following was demonstrated.
Generally, the intensity | strength of a glass plate is raised by provision of the compressive stress to the glass surface by chemical strengthening. However, since the strength of the glass plate is also affected by the surface state of the glass plate, it is important to control the surface state of the glass plate in order to obtain a desired strength. If the glass plate controlled so that the BOR minimum strength before chemical strengthening is 400 N or more as the surface state of the glass plate is chemically strengthened, the strength after the chemical strengthening step can satisfy 2J of the UL60065 standard.

  And the BOR minimum intensity | strength of the glass plate before chemical strengthening will be 400 N or more by using the roll brush from which brush tip reaction force P1 will be 0.40 N or less in a 1st washing | cleaning process (S2).

  In the second cleaning step (S4), the glass plate need not be cleaned with a roll brush having a brush tip reaction force P1 of 0.40 N or less as in the first cleaning step (S2). By washing the glass plate with a roll brush having a tip reaction force P1 of 0.40 N or less, the glass plate after chemical strengthening can maintain desired impact resistance.

  The present invention is not limited to the embodiment described above, and can be implemented in various forms without departing from the gist of the present invention.

20 Display panel 30 Cover glass 40 Display device

Claims (5)

A display comprising: a shape processing step for processing a glass plate for a display device into a glass plate having a predetermined shape; a cleaning step for cleaning the glass plate; and a chemical strengthening step for chemically strengthening the cleaned glass plate. A method for manufacturing a cover glass for an apparatus, comprising:
In the cleaning step, after the cleaning step, the tip of the roll brush is brought into contact with at least one main surface of the glass plate so that the BOR strength of the glass plate before the chemical strengthening step is 400 N or more. A method for producing a cover glass for a display device, wherein the glass plate is washed. Brush tip represented by the following formula (A) when the length of the brush wire constituting the roll brush is L (mm), the wire diameter is d (mm), the Young's modulus is E (Pa), and the deflection is 1 mm. The method for producing a cover glass for a display device according to claim 1, wherein the reaction force P1 is P1≤0.40N.

A display comprising: a shape processing step for processing a glass plate for a display device into a glass plate having a predetermined shape; a cleaning step for cleaning the glass plate; and a chemical strengthening step for chemically strengthening the cleaned glass plate. A method for manufacturing a cover glass for an apparatus, comprising:
In the cleaning step, the glass plate is cleaned by bringing the tip of a roll brush into contact with at least one main surface of the glass plate,
Brush tip represented by the following formula (A) when the length of the brush wire constituting the roll brush is L (mm), the wire diameter is d (mm), the Young's modulus is E (Pa), and the deflection is 1 mm. Reaction force P1 is P1 ≦ 0.40N, The manufacturing method of the cover glass for display apparatuses characterized by the above-mentioned.

  Using a roll brush having a brush tip reaction force P1 satisfying P1 ≦ 0.40N, the tip of the roll brush is brought into contact with the at least one main surface of the chemically strengthened glass plate. The method for producing a cover glass for a display device according to claim 2 or 3, wherein the glass plate is washed.   The thickness of the said glass plate is 0.5 mm-2.0 mm, The manufacturing method of the cover glass for display apparatuses of any one of Claims 1-4 characterized by the above-mentioned.

Images