WO2011052529A1 - Glass substrate for display and method for manufacturing the glass substrate - Google Patents

Abstract

Disclosed is a highly flat glass substrate for a display, wherein sufficient strength is ensured by reducing generation of a recessed shape of the polished surface. Also disclosed is a method for manufacturing such glass substrate. The glass substrate (15) on the display surface side of the flat panel display is characterized in that the depth of the recessed shape is less than 10nm in a center region (12), which has an area of 20 % or more of the whole area of the surface (11a) facing the inside of the flat panel display.

Description

Glass substrate for display and manufacturing method thereof

The present invention relates to a glass substrate for display and a manufacturing method thereof, and more particularly to a glass substrate for display used for a flat panel display and a manufacturing method thereof.

Conventionally, as a polishing method and apparatus for manufacturing a glass substrate for liquid crystal display, it has a carrier that sticks and supports a substrate on a film frame, and a polishing surface plate, and the carrier and the polishing surface plate are relatively For example, a technique for polishing a substrate by pressing the polishing surface of the substrate against a polishing surface plate is known (see, for example, Patent Document 1).

In Patent Document 1, a glass substrate is attached to a film frame of a carrier, and after polishing is completed, the glass substrate is not removed from the film frame by a polishing stage provided near the polishing surface plate. The glass substrate after polishing is removed from the film frame at the glass substrate removal stage away from the film. Thereby, the problem concerning the carrying-out of the glass substrate peculiar to a large sized glass substrate is eliminated.

Japanese Unexamined Patent Publication No. 2004-122351

In the configuration described in Patent Document 1, the problem of carrying out a large glass substrate can be solved. However, the polishing of the glass substrate itself is performed by general polishing, and the polishing slurry contains an aqueous cerium oxide solution. Is used. The abrasive grains of cerium oxide contained in the polishing slurry using an aqueous cerium oxide solution generally have a particle size of about 1100 nm. When polishing is performed using the abrasive particles having this particle size, a polishing step is performed. There has been a problem that a dent shape of 15 nm or more may remain on the polished surface of the glass substrate without completely removing the dent shape generated before.

On the other hand, a certain degree of strength is required for a display panel. For example, in a glass substrate for a liquid crystal display, after the liquid crystal display panel is manufactured, a strength test may be performed by pressing or the like. On the color filter substrate of the liquid crystal display panel, after manufacturing the liquid crystal display panel, a black matrix made of a chromium film is formed as a light shielding film in addition to the color filter. Here, if there is a dent shape on the surface of the chrome film, cracks are likely to occur from the dent shape of the chrome film, and the strength of the liquid crystal display panel is deteriorated compared with the case where there is no dent shape on the surface of the chrome film. In the test, there was a problem that good results could not be obtained. And it has been confirmed that such a dent shape of the chromium film may occur due to the dent shape existing in the glass substrate for the color filter under the chromium film.

Also, in other display panels such as an organic EL (Electro-Luminescence) panel, a glass substrate is used, and a strength test by pressurization or the like may be similarly performed. In such various display panels, the glass substrate is not necessarily formed into a film, but the glass substrate is required to have a predetermined substrate strength even when the film is not formed. In addition, the substrate strength is higher when the glass substrate has fewer concave shapes.

Therefore, an object of the present invention is to provide a glass substrate for a display with high flatness that can reduce the occurrence of a dent shape on the surface of the substrate and ensure sufficient strength, and a method for manufacturing the same.

To achieve the above object, the glass substrate for display according to the first invention is a glass substrate on the display surface side of the flat panel display, and is 20% or more of the entire area of the surface facing the inside of the flat panel display. And the depth of the recessed shape is less than 10 nm.

This makes it possible to improve the flatness of the inner surface of the central region where stress is easily applied, and to improve the strength of the glass substrate when used in a flat panel display.

According to a second invention, in the glass substrate for display according to the first invention, an average breaking load when a load is applied from a surface facing the outside of the flat panel display is 600 when the plate thickness is tmm. X (t / 0.5) ² N or more.

Thereby, even when stress is applied from the outside of the flat panel display, it is possible to prevent the breakdown with sufficient strength and to improve the reliability of the flat panel display.

The third invention is the glass substrate for display according to the first or second invention, wherein the flat panel display is a liquid crystal display, and the display surface side is a color filter side.

As a result, even when a chromium film is formed as a black matrix on the color filter forming surface of the glass substrate, cracks generated in the chromium film due to the concave shape of the glass substrate are prevented, and the liquid crystal panel resulting therefrom It is possible to prevent the deterioration of strength.

According to a fourth invention, in the glass substrate for display according to the first or second invention, the flat panel display is an organic EL display, and the display surface side is a cap glass side. .

Thus, even when the glass substrate is used in a top emission type organic EL display, it can be applied with sufficient strength against external stress.

According to a fifth invention, in the glass substrate for display according to the first or second invention, the flat panel display is an organic EL display, and the display surface side is a TFT glass substrate side. To do.

Thus, even when the glass substrate is used in a bottom emission type organic EL display, it can be applied with sufficient strength against external stress.

A method for producing a glass substrate for display according to a sixth invention is a method for producing a glass substrate for display used in a flat panel display, wherein a step of forming a glass substrate and one surface of the glass substrate is polished. As a step of installing the glass substrate in a polishing apparatus that performs polish polishing using abrasive grains, a step of polishing the polishing surface of the glass substrate using abrasive grains having an average particle size of 80 nm or less, It is characterized by including.

As a result, it is possible to perform fine polish polishing using abrasive grains having a small particle diameter, to increase the flatness of the polished surface of the glass substrate, and to have a recess shape with a recess shape depth of 10 nm or more. Glass substrates can be manufactured.

The seventh invention is characterized in that, in the method for producing a glass substrate for display according to the sixth invention, the abrasive grains contain colloidal silica.

Thereby, it is possible to construct an abrasive grain having a particle size much smaller than that of abrasive grains using cerium oxide having a grain size of about 1100 nm, which is generally used, and 80 nm or less, for example, 50 nm or 40 nm. A glass substrate for display with high flatness can be manufactured using fine abrasive grains of 20 nm.

The eighth invention is characterized in that in the method for producing a glass substrate for display according to the seventh invention, the abrasive grains have an average particle diameter of 20 nm or less.

A ninth invention is a method for producing a glass substrate for display according to any one of the sixth to eighth inventions,
The step of forming the glass substrate is characterized in that the glass substrate is formed by a float method.

Thus, a large glass substrate can be formed, and a large flat glass substrate for display can be manufactured.

A tenth invention is a method for producing a glass substrate for display according to any one of the sixth to ninth inventions,
The flat panel display is a liquid crystal display,
The film forming surface is a color filter forming surface of a color filter substrate.

Thereby, it is possible to supply a glass substrate for liquid crystal display having a strength sufficient to withstand the strength test of the liquid crystal display panel.

An eleventh invention is the method for producing a glass substrate for display according to the tenth invention, wherein the color filter forming surface is a surface on which a black matrix composed of a chromium film is formed before the color filter is formed. It is characterized by.

Thereby, in the strength test of the liquid crystal display panel, sufficient strength can be ensured even for the portion of the chromium film which is liable to crack.

A twelfth invention is a method for producing a glass substrate for display according to any one of the sixth to ninth inventions,
The flat panel display is an organic EL display, and the polishing surface is an inner surface of a cap glass.

Thereby, a glass substrate having sufficient strength that can withstand the strength test of the top emission type organic EL display can be manufactured.

A thirteenth invention is a method for producing a glass substrate for display according to any one of the sixth to ninth inventions,
The flat panel display is an organic EL display, and the polishing surface is an inner surface of a TFT glass substrate.

Thereby, it is possible to provide a glass substrate having sufficient strength that can withstand the strength test of the bottom emission type organic EL display.

According to the present invention, the flatness of the glass substrate for display can be increased and the strength of the display panel of the flat panel display can be increased.

3 is a diagram illustrating an example of a color filter side glass substrate 15 of the liquid crystal panel according to Embodiment 1. FIG. FIG. 1A is a plan view of the film forming surface 11a of the color filter side glass substrate 15 according to the first embodiment. FIG. 1B is a cross-sectional view of the color filter side glass substrate 15 according to the first embodiment. It is the figure which showed an example of the intensity test of the liquid crystal panel 50 of a liquid crystal display. It is explanatory drawing of the crack generation mechanism of the color filter side glass substrate. FIG. 3A is an example of a surface enlarged view of a chromium film formed on a conventional color filter side glass as a comparative example. FIG. 3B is an enlarged view of the X-X ′ cross section of FIG. FIG.3 (c) is an enlarged view of the hollow shape 21 of a chromium film | membrane. FIG. 3D is an enlarged view of the concave shape 22 of the chromium film. It is an example of the enlarged view of the film-forming surface 11a of the color filter side glass substrate 15. It is a figure for demonstrating an example of the glass substrate formation process of the manufacturing method of the glass substrate 10 for a display which concerns on Embodiment 1. FIG. It is a figure for demonstrating an example of the grinding | polishing process of the manufacturing method of the glass substrate 10 for a display which concerns on Embodiment 1. FIG. It is the figure which showed an example of the grinding | polishing apparatus 300 different from the grinding | polishing apparatus 100 which concerns on FIG. It is the figure which showed the film-forming surface 11 of the glass substrate 10 for a display which concerns on Embodiment 1. FIG. FIG. 8A is an enlarged view of the film formation surface 11 of the display glass substrate 10 according to the first embodiment. FIG. 8B is an enlarged cross-sectional view corresponding to FIG. It is a figure for demonstrating the method of an intensity | strength test. It is the figure which showed the strength test result of the glass substrate for displays in which the chromium film was formed. 6 is a diagram illustrating an example of a cross-sectional configuration of a top emission type organic EL panel 51 using a display glass substrate according to Embodiment 2. FIG. 6 is a diagram illustrating an example of a cross-sectional configuration of a bottom emission type organic EL panel 52 using a display glass substrate according to Embodiment 3. FIG.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

FIG. 1 is a view showing an example of a color filter side glass substrate 15 of a liquid crystal panel according to Embodiment 1 of the present invention. 1A is a plan view of a film forming surface 11a of the color filter side glass substrate 15 of the liquid crystal panel according to the first embodiment, and FIG. 1B is a color filter side of the liquid crystal panel according to the first embodiment. 2 is a cross-sectional view of a glass substrate 15. FIG.

In FIG. 1A, the film formation surface 11a of the color filter side glass substrate 15 is shown, but the central region 12 of the film formation surface 11a is shown to include the center of gravity of the film formation surface 11a. The central region 12 is a region that is 20% or more of the entire area of the film formation surface 11a. The central region 12 is a region where a crack such as a crack is likely to occur in the film formed on the color filter side glass substrate 15 when a strength test of a liquid crystal panel including the color filter side glass substrate 15 is performed. It is.

FIG. 2 is a diagram showing an example of a strength test of the liquid crystal panel 50 of the liquid crystal display. In FIG. 2, a cross-sectional view of the liquid crystal panel 50 is shown. The liquid crystal panel 50 includes a color filter side glass substrate 15 cut to a predetermined size from a color filter glass substrate, and a TFT side glass 16 cut to a predetermined size from a TFT (Thin Film Transistor) glass substrate. Is provided. A spacer or the like is provided between the color filter side glass substrate 15 and the TFT side glass 16, and supports the color filter side glass substrate 15 and the TFT side glass 16, and the color filter side glass substrate 15 and the TFT side. A liquid crystal layer is formed between the glass 16 and the liquid crystal layer is omitted in FIG.

In the color filter side glass substrate 15, a black matrix 20 and a color filter 30 are formed on a film forming surface 11 a which is a surface facing the TFT side glass 16. That is, the film formation surface 11 a of the color filter side glass substrate 15 is a color filter formation surface and is a surface facing the inside of the liquid crystal panel 50. The color filter 30 is a filter for passing only light of a specific wavelength and displaying a color. In the liquid crystal panel 50, the color filter 30 is generally configured as a resin film containing a dye or a pigment, and the three primary color patterns of red, green, and blue are regularly arranged. The black matrix 20 is a light shielding film and is formed between the colors of the color filter 30. The black matrix 20 is often formed of a chromium (Cr) film.

In the TFT side glass 16, for example, an amorphous silicon film 40 is formed in order to form a thin film transistor on the film forming surface 11b which is the surface facing the color filter side glass substrate 15.

As the liquid crystal panel 50, a backlight is disposed on the back surface of the TFT side glass 16, and light is irradiated from the back surface (below the TFT side glass 16 in FIG. 2). Then, the liquid crystal is driven by the thin film transistor, and an image of each color is displayed on the front surface of the color filter side glass substrate 15 (above the color filter side glass substrate 15 in FIG. 2) through the color filter 30. Become.

As a strength test of the liquid crystal panel 50, as shown in FIG. 2, the center portion of the surface facing the outside of the liquid crystal panel 50 above the color filter side glass substrate 15 side with the liquid crystal panel 50 placed horizontally. Therefore, a test for pressurizing with the pressurizing jig 60 is generally performed. When the strength test is performed, if the strength of the liquid crystal panel 50 is insufficient, the liquid crystal panel 50 is destroyed. Here, the destruction of the liquid crystal panel 50 may start from the color filter side glass substrate 15 instead of the TFT side glass 16. In addition, when the color filter side glass substrate 15 is broken, a crack starting point is generated on the surface of the black matrix 20 during pressurization, and the extended crack propagates to the color filter side glass substrate 15 and the liquid crystal panel 50 It has been confirmed that it may lead to destruction. Further, in the strength test of the liquid crystal panel 50, as shown in FIG. 2, since pressure is applied from the central region of the color filter side glass substrate 15, the occurrence of cracks is greater in the central region than in the peripheral portion. .

FIG. 3 is a view for explaining a mechanism of generating cracks in the color filter side glass substrate 15. FIG. 3A is a view showing an example of a surface enlarged view of a chromium film on which a black matrix 20 of a conventional color filter side glass is formed as a comparative example. FIG. 3A shows a state in which the concave shapes 21 and 22 are formed to extend linearly on the surface of the black matrix 20. Further, in FIG. 3A, XX ′ indicates a FIB (Focused Ion Beam) processing position, and the center arrow indicates an observation direction.
FIG. 3B is an enlarged view of the section XX ′ in FIG. In FIG. 3B, the protective layer 70 is formed on the chromium film of the black matrix 20 to perform the FIB processing, and then cut by performing the FIB processing, and the cross section is enlarged. . In FIG.3 (b), the location of the recessed shapes 21 and 22 is shown.

FIG. 3C is a further partial enlarged view of the recess 21 of the chromium film shown in FIG. As shown in FIG. 3 (c), a concave shape 13 is formed in the color filter side glass below the portion where the concave shape 21 is formed on the surface of the chromium film, similarly to the chromium film.

FIG. 3 (d) is a further enlarged view of the chrome film recess 22 shown in FIG. 3 (b). As shown in FIG. 3 (d), the concave shape 14 is formed in the color filter side glass in the lower layer where the concave shape 22 is formed on the surface of the chromium film.

When a strength test is performed on the liquid crystal panel 50 in a state where such a chrome film having the concave shapes 21 and 22 on the surface is formed on the color filter side glass as the black matrix 20, the concave shapes 21 and 22 of the chrome film are obtained. It has been confirmed that there is a case in which a crack is generated from the liquid crystal panel 50 and this crack propagates to the color filter side glass substrate 15 to generate a crack, which eventually leads to destruction of the liquid crystal panel 50.

From this, it can be seen that in the strength test, if the concave shapes 21 and 22 are present on the surface of the black matrix 20 of the chrome film, the pressurizing stress during the strength test tends to be concentrated locally and the strength is remarkably reduced. On the other hand, since the concave shapes 13 and 14 of the color filter side glass are present at the locations where the concave shapes 21 and 22 on the surface of the chromium film are present, the concave shapes 21 and 22 on the surface of the chromium film are the color filter side glass. It can be seen that this occurs due to the concave shapes 13 and 14.

As described with reference to FIG. 3, if the concave shape of the film formation surface 11 a that is the inner surface of the liquid crystal display of the color filter side glass substrate 15 is reduced, cracks in the black matrix 20 made of a chromium film can be prevented or reduced. Can do. Therefore, if the concave shapes 13 and 14 can be reduced in the central region 12 of the color filter side glass substrate 15 shown in FIGS. 1A and 1B, the color filter side glass substrate 15 has sufficient strength. You can see that

FIG. 4 is a diagram showing an example of an enlarged view of the film forming surface 11a of the color filter side glass substrate 15 of the liquid crystal panel shown in FIG. 1 (b). As shown in FIG. 4, when the film formation surface 11a of the color filter side glass substrate 15 is enlarged, it can be seen that minute unevenness exists instead of a complete flat surface. In FIG. 4, two recessed shapes 13 and 14 are present on the film formation surface 11 a of the color filter side glass substrate 15. Of the irregularities, the concave shapes 13 and 14 are disadvantages that can cause the concave shapes 21 and 22 on the surface of the black matrix 20 to occur. Here, if the depth of the dent shapes 13 and 14 is less than 10 nm, even if the strength test is performed, cracks are unlikely to occur in the black matrix 20 made of a chromium film, and good test results can be obtained in the strength test. It has been confirmed. Examples based on specific experimental results will be described later, but the liquid crystal panel 50 can obtain good test results in the strength test if the concave shapes 13 and 14 have such a flatness as to be less than 10 nm. .

In addition, although it is preferable that the area | region where the concave shapes 13 and 14 of the color filter side glass substrate 15 are less than 10 nm is large, as demonstrated in FIG. 1, at least 20% or more of the whole area of the film-forming surface 11a is preferable. If the depth of the recessed shapes 13 and 14 is configured to be less than 10 nm in the central region of the area, sufficient strength improvement of the liquid crystal panel 50 can be obtained. The central region 12 may be a region centered on at least the shape center of the outer diameter of the film formation surface 11. The central region 12 is preferably at least 20% of the entire film formation surface 11. When the film formed on the color filter side glass substrate 15 is more susceptible to cracking, it is more preferably 30% or more, further preferably 40% or more, and more preferably 50% or more. Particularly preferred.

Next, an example of a method for manufacturing the display glass substrate 10 according to the embodiment of the present invention will be described with reference to FIGS. 1 to 4, the color filter side glass substrate 15 of the liquid crystal panel has been described as an example, but the method for manufacturing the display glass substrate 10 according to Embodiment 1 is for other displays such as a plasma display panel. It can also be applied to other glass substrates. Therefore, in FIG.5 and FIG.6, the manufacturing method of the glass substrate 10 for a display applicable also to display panels other than a liquid crystal panel is demonstrated.

FIG. 5 is a view for explaining an example of the glass substrate forming step of the method for manufacturing the display glass substrate 10 according to the first embodiment. FIG. 5 shows an example of the overall schematic configuration of a float glass manufacturing facility 80 that manufactures a glass substrate by the float process.

The float glass manufacturing facility 80 includes a melting kiln 81, a float bath 82, and a slow cooling kiln 87. The float bath 82 includes a gas supply port 83 and a heater 84. The slow cooling furnace 87 includes a heater 88. Further, a draw roll 86 is provided between the float bath 82 and the slow cooling furnace 87.

Next, an example of a method for manufacturing a glass substrate using the float glass manufacturing facility 80 will be described. The maximum temperature of the melting furnace 81 reaches 1550 to 1600 ° C. due to heavy oil combustion. The glass raw material 5 is supplied to the melting furnace 81 and melted in the melting furnace 81 to become the molten glass 6. In the melting furnace 81, the molten glass 6 is supplied to the float bath 82 after being made into the homogeneous molten glass 6 without bubbles. The float bath 82 is a shallow tin bath filled with molten tin 90. In addition, a reducing gas composed of a mixed gas of hydrogen and nitrogen for preventing oxidation of tin is supplied to the space above the float bath 82. The heater 84 adjusts the temperature as necessary so that the temperature of the molten glass 6 supplied to the float bath 82 is about 1050 ° C. upstream and about 600 ° C. downstream. In the vicinity of the outlet downstream of the float bath 82, the glass is solidified, but the solidified glass is transferred to the slow cooling kiln 87 by the drawing roll 86. In the slow cooling furnace 87, after the glass is cooled and strain is removed, the glass substrate is formed by inspection and cutting.

For example, the glass substrate forming step may be performed using a float process. In addition to the float process, the glass substrate forming step may be executed by other glass substrate manufacturing methods such as a fusion method. In the glass substrate forming step, various glass substrate manufacturing methods can be applied as long as a glass substrate as a material for manufacturing the display glass substrate 10 can be manufactured.

FIG. 6 is a diagram for explaining an example of a polishing process according to the first embodiment. FIG. 6 shows an example of the overall configuration of the polishing apparatus 100 of the first embodiment.

The polishing apparatus 100 includes two polishing apparatuses 101 and 102, a first polishing apparatus 101 and a second polishing apparatus 102. The first polishing apparatus 101 and the second polishing apparatus 102 are each provided with a polishing head 150. Since both have the same configuration, the same reference numerals are assigned to the same components. explain.

The polishing head 150 is configured such that a motor is built in a main body casing 151, and an output shaft of the motor is connected to a spindle 156 suspended in a vertical direction. A carrier 152 is connected to the spindle 156. The main body casing 151 is connected to a slider 258 via an elevating mechanism 256. As the main body casing 151 is moved up and down with respect to the slider 258 by the lifting mechanism 256, the carrier 152 is moved forward and backward with respect to the polishing pad 158 of the first polishing stage 118 and the polishing pad 160 of the second polishing stage 120. In addition, the glass substrate 7 adhered to the film frame 114 can be pressed against the polishing pads 158 and 160 with a predetermined polishing pressure.

The polishing pad 158 is affixed to the upper surface of the polishing surface plate 162, and a rotating shaft 164 rotated by a motor (not shown) is connected to the lower portion of the polishing surface plate 162. The polishing pad 160 is affixed to the upper surface of the polishing surface plate 166, and a rotating shaft 168 that is rotated by a motor (not shown) is connected to the lower portion of the polishing surface plate 166. Since the polishing pads 158 and 160 may not necessarily rotate, a motor is not necessarily required. Further, the polishing pads 158 and 160 may be swung.

Furthermore, the main body casing 151 may be connected to a revolution drive mechanism (not shown) and have a function of revolving at a predetermined revolution radius. The revolution drive mechanism can be configured by, for example, incorporating a planetary gear mechanism in the main body casing 151 and connecting the output shaft of the planetary gear mechanism to the spindle 156.

Further, the polishing apparatus 100 includes transfer apparatuses 250, 252, and 254. Each of the transport devices 250, 252, and 254 includes a guide rail 270. The transport device 250 includes a stage 116, and the transport device 254 includes a stage 122. The glass substrate 7 moves on the stages 116 and 122 by the guide rail 270. Further, the transfer devices 250, 252, and 254 include robot arms (not shown), and the stage 116 to the first polishing stage 118, the first polishing stage 118 to the second polishing stage 120, and the second polishing stage 120 to the stage. The glass substrate 7 can be moved to 122.

The polishing platen 162 is provided with a slurry supply hole 130. Similarly, the polishing platen 166 is provided with a slurry supply hole 131. From the slurry supply holes 130 and 131, aqueous slurry containing abrasive grains is supplied. For polishing the glass substrate 7, slurry containing abrasive grains is supplied from the slurry supply holes 130, 131, and the polishing plates 162, 166 and the carrier 152 rotate while the carrier 52 moves the polishing surface of the glass substrate 7. This is done by holding it downward and pressing the polishing surface against polishing pads 158 and 160 on polishing surface plates 162 and 166. Further, the polishing pads 158 and 160 may be formed with grooves for flowing slurry.

The carrier 152 is formed with a plurality of ejection ports (not shown) through which compressed air is ejected. These injection ports communicate with an air supply path 202 indicated by a broken line in FIG. The air supply path 202 extends to the outside of the polishing head 150 via a rotary joint (not shown) attached to the polishing head 150, and is connected to the air pump 206 via a valve 204. Therefore, when the valve 204 is opened, compressed air from the air pump 206 is supplied to the injection port in the carrier 152 via the air supply path 202. Thereby, the pressure of the compressed air is transmitted to the glass substrate 7, and the glass substrate 7 is pressed against the polishing pads 158 and 160 by this pressure and polished.

For example, the polishing process of the glass substrate 7 may be performed by the polishing apparatus 100 having such a configuration. Specifically, the glass substrate 7 is moved from the stage 116 onto the first polishing stage 118 by the transfer device 250 and held by the carrier 152 with the polishing surface facing downward. That is, the glass substrate 7 is installed in the first polishing apparatus 101. Then, the carrier 152 and the polishing surface plate 162 rotate, and slurry containing abrasive grains is supplied from the slurry supply hole 130. The glass substrate 7 is polished by both mechanical polishing action by friction with the polishing pad 158 and the abrasive grains on the polishing platen 162 and chemical polishing action by chemical reaction with the slurry.

Here, in the conventional polishing process, the polishing process is performed using a slurry containing abrasive grains of cerium oxide (CeO ₂ ). However, the abrasive grains of cerium oxide have an average particle size of 1.1 μm (= 1100 nm). Therefore, when the polishing process is performed using the cerium oxide abrasive grains, the dent shape generated before the polishing process shown in FIG. 3 is not completely removed, and the dent shape of 15 nm or more is formed on the polishing surface of the glass substrate for display. There was a problem that it might remain. Examples of the dent shape generated before the polishing step include scratches caused by handling in the step before the polishing step and conveyance scratches.

Therefore, in the method for manufacturing the glass substrate 10 for display according to this embodiment, abrasive grains of colloidal silica are used. As a slurry using colloidal silica as abrasive grains, a colloidal silica slurry in which spherical silica particles having an average particle diameter of 80 nm are dispersed is used. Thereby, a slurry containing fine abrasive grains having an average particle size of 80 nm or less can be obtained. Moreover, it is also possible to make the average particle size of the particle size in the slurry 20 nm or less by using a slurry using abrasive grains having an average particle size of 20 nm or less.

By using such abrasive grains having a small particle diameter, the concave shapes 13 and 14 of the film forming surface 11 of the display glass substrate 10 can be made to have an average depth of less than 10 nm in the polishing step. Further, by adjusting the rotational speed, polishing pressure, etc., the depth of the dent shape can be less than 8 nm on average and even less than 5 nm on average.

Thus, in the manufacturing method of the glass substrate 10 for a display which concerns on this embodiment, the film-forming surface 11 of the glass substrate 10 for displays is used for the whole area of the film-forming surface 11 by using a small grain size abrasive grain. In the central region 12 of 20% or more, the depth of the recessed shapes 13 and 14 can be processed to be less than 10 nm. Thereby, sufficient strength can be achieved also in the strength test of the liquid crystal display panel.

In addition, in the manufacturing method of the glass substrate 10 for a display which concerns on this embodiment, if it can implement | achieve the particle size of 80 nm or less, Preferably it is 50 or 40 nm or less, More preferably, it is 20 nm or less, the abrasive grain comprised from various materials will be used. The present invention can be applied to the method for manufacturing the display glass substrate 10 according to the present embodiment.

After completion of polishing by the first polishing apparatus 101, the glass substrate 7 is moved to the second polishing stage 120 by the transfer apparatus 252. Then, the glass substrate 7 is placed on the carrier 152, and the polishing platen 166 and the carrier 152 are rotated while the abrasive grains having the same particle diameter of 80 nm or less are supplied from the slurry supply hole 131 to polish the glass substrate 7. I do. Also in this case, for example, since small-diameter abrasive grains are used, polishing can be performed in the central region of the polishing surface of the glass substrate 7 so that the depth of the concave shape is less than 10 nm.

Further, when the polishing by the second polishing apparatus 102 is completed, the glass substrate 7 is moved from the second polishing stage 120 to the stage 122 by the transfer apparatus 254, and the polishing process is ended. Thereafter, cleaning or the like may be performed as necessary.

As described above with reference to FIG. 5 and FIG. 6, the glass substrate 7 is first created, the created glass substrate 7 is installed in the polishing apparatus 100, and a slurry containing abrasive grains having a particle size of 80 nm or less is used. By polishing the film formation surface 11 of the glass substrate 7, the glass substrate 10 for a display according to the present embodiment in which the depths of the recessed shapes 13 and 14 are less than 10 nm can be manufactured.

Moreover, in the manufacturing method of the glass substrate 10 for a display which concerns on this embodiment, although the example of the 2 step | paragraph grinding | polishing using the 1st grinding | polishing apparatus 101 and the 2nd grinding | polishing apparatus 102 was given and demonstrated, these are 1 step | paragraphs. You may complete | finish by grinding | polishing. The number of times of polishing, time, and other various polishing conditions may be set in accordance with the application.

Next, with reference to FIG. 7, a polishing process by the polishing apparatus 300 different from the polishing apparatus 100 according to FIG. 6 will be described. FIG. 7 is a plan view showing an example of a polishing apparatus 300 different from the polishing apparatus 100 according to FIG.

7 includes an adsorption sheet 312 and a circular polishing tool 314. The polishing apparatus 300 polishes the glass substrate 7 using circular polishing tools 314 arranged in a staggered manner. For example, the glass substrate 7 for display having a size of 2200 mm (width) × 2600 mm (length) or more may be used for polishing.

In FIG. 7, the glass substrate 7 to be polished is held on the suction sheet 312 adhered to a table (not shown) by suction and holding the surface opposite to the surface to be polished, as shown by an arrow X in the drawing. It is continuously transported by the transport device. During polishing, the surface to be polished is polished to the flatness required for the glass substrate 10 for display by a plurality of circular polishing tools 314, 314,... Of a polishing machine installed above the transfer path.

As shown in the figure, the circular polishing tools 314, 314,... Have a diameter D smaller than the width W of the glass substrate 7, and are rotated around a predetermined rotation center by a rotation / revolution mechanism (not shown). At the same time, the glass substrate 7 is polished while being revolved around a predetermined revolution center. In FIG. 7, circles indicated by solid lines indicate the current postures of the circular polishing tools 314, 314..., And many circles indicated by two-dot chain lines indicate that the glass substrate 7 has the polishing tools 314, 314. The edge part of the part which contacted with is shown. As can be seen from these circles, the polishing tools 314, 314,... Are revolved around a predetermined revolution center.

Further, the circular polishing tools 314, 314,... Are arranged in pairs with the movement center line L of the glass substrate 7 as a reference, and are arranged in a staggered manner with their positions shifted in the movement direction. Are disposed so as to polish the glass substrate 7 beyond the moving center line L.

According to the polishing apparatus 300 configured in this way, instead of using one large polishing tool, a plurality of small circular polishing tools 314 having a diameter D smaller than the width W of the glass substrate 7 are arranged. Are arranged in pairs on the left and right with respect to the movement center line L of the glass substrate 7, and the circular polishing tools 314, 314... Polish the glass substrate G beyond the center line L. As a result, the entire surface of the glass substrate 7 can be polished. As an example, when the width of the glass substrate 7 is 2200 mm, the size of the circular polishing tool 314 is φ1290 mm, the revolution radius is 75 mm, and the revolution center is set at a position 600 mm away from the moving center line L in the right and left directions. it can.

7, since the circular polishing tool 314 is reduced in size and diameter, problems such as securing the material of the circular polishing tool 314, maintaining processing and assembly accuracy, replacement work, and handling can be solved. Further, since the circular polishing tools 314, 314... Are arranged in at least two staggered patterns along the moving direction of the glass substrate 7, the plate-like body can be polished evenly and accurately.

As described above, the polishing step may be performed using a polishing apparatus 300 in which circular polishing tools 314 are arranged in a staggered manner as shown in FIG. When performing a polishing process using the polishing apparatus 300 according to FIG. 7, by supplying a slurry having an average particle size of 80 nm or less using the above-mentioned colloidal silica as abrasive grains, the depth of the concave shapes 13 and 14 on the surface can be reduced. The glass substrate 10 for a display containing the area | region less than 10 nm can be manufactured. Similarly to the description in FIG. 6, a slurry containing abrasive grains having an average particle size of 50 nm or less, 40 nm or less, or 20 nm or less may be used. The other detailed contents are the same as those in FIG.

As described with reference to FIGS. 6 and 7, in the method for manufacturing the glass substrate for display 10 according to the present embodiment, the polishing step can be performed by various polishing methods. At that time, the glass substrate 10 for display including the area | region where the depth of the recessed shape 13 and 14 of a grinding | polishing surface is less than 10 nm is manufactured by grind | polishing using the slurry containing an abrasive grain with an average particle diameter of 80 nm or less. be able to. Then, the display panel is arranged so that the polishing surface is the film formation surface 11 and the region where the depth of the recessed shapes 13 and 14 is less than 10 nm covers the central region 12 having an area of 20% or more of the entire area of the film formation surface 11. If comprised, it can be set as a display panel with high intensity | strength.

Further, in the method for manufacturing the display glass substrate 10 according to the present embodiment, the manufacturing process can be applied to the glass substrate 7 before the liquid crystal panel 50 is manufactured. By using abrasive grains having a particle size of 80 nm or less, it is possible to manufacture the glass substrate 10 for display in which the depth of the recessed shapes 13 and 14 is less than 10 nm in most regions of the glass substrate 7. Thereafter, even when the glass substrate for display 10 is cut as the color filter side glass substrate 15 for the 5 cm × 5 cm liquid crystal panel 50 for strength test, the original large-sized glass substrate for display 10 has a depth of 10 nm. Most of the portions include only the recessed shapes 13 and 14 having a depth less than 10 nm, and therefore, the central region 12 including only the recessed shapes 13 and 14 having a depth of less than 10 nm can be easily formed.

In Example 1, the results of carrying out the method for manufacturing the display glass substrate 10 according to Embodiment 1 will be described.

FIG. 8 is a view showing a film forming surface 11 of the display glass substrate 10 manufactured by the method for manufacturing the display glass substrate 10 according to the first embodiment. The film formation surface 11 is also a surface facing the inside of the liquid crystal panel 50 of the liquid crystal display.

FIG. 8A is an enlarged view of the film-forming surface 11 of the display glass substrate 10 according to the first embodiment, that is, the polished surface. The enlargement magnification is the same as that shown in FIG. In FIG. 8A, it can be seen that the recessed shapes 13 and 14 that are linear in FIG. 3A do not exist in FIG. 8A. Thus, it turns out that the manufacturing method of the glass substrate 10 for a display which concerns on Embodiment 1 can implement | achieve the flatness which reduces the dent shapes 13 and 14 significantly.

FIG. 8B is an enlarged cross-sectional view corresponding to FIG. Thus, the film-forming surface 11 of the glass substrate 10 for a display is entirely flat, and the recessed shapes 13 and 14 do not exist. Therefore, naturally, in the central region, the recessed shapes 13 and 14 are not present.
Next, using FIG. 9 and FIG. 10, a chromium film is formed on the film formation surface 11 of the display glass substrate 10 manufactured by the method for manufacturing the display glass substrate 10 according to Embodiment 1, and a strength test is performed. The results will be described.

FIG. 9 is a diagram for explaining the strength test method. In FIG. 9, a sample 500 of the liquid crystal panel 50 is installed on the receiving jig 61. In the strength test of the liquid crystal panel 50, the strength test is performed using a sample 500 of the 5 cm square liquid crystal panel 50. Therefore, the size may differ from the liquid crystal panel 50 actually used for the liquid crystal display. Moreover, it may test not with a liquid crystal panel state but with the single plate cut out to 5 cm square from the glass substrate 10 for a display. The center region of the sample 500 is pressurized from above the sample 500 using the pressing jig 60. Note that the pressure surface at this time is a surface facing the outside of the liquid crystal panel 50 of the liquid crystal display. The same test method as the strength test described in FIG. 2 is adopted.

FIG. 10 is a diagram showing the strength test results of a glass substrate for display on which a chromium film is formed. In FIG. 10, it is the figure which compared the intensity | strength by the difference in the depth of the dent shape of the surface of the glass substrate 10 for a display. In FIG. 10, the horizontal axis represents the pressure applied by the pressing jig 60 [kgf], and the vertical axis represents the cumulative failure probability (CumulativemulFailure Probability) [%].

Curve C is the result when the conventional glass substrate 10 for display is manufactured by performing a polishing process using cerium oxide as an abrasive grain. In this case, on the polishing surface serving as the film formation surface 11 of the glass substrate 10 for display, concave shapes 13 and 14 of 15 nm or more occurred. And it showed the weakest strength.

Curve B is the strength test result of the display glass substrate 10 manufactured by the method for manufacturing the display glass substrate 10 according to the first embodiment. As the slurry, colloidal silica having an average grain size of 80 nm was used. In this case, on the film-forming surface 11 of the glass substrate 10 for display, the depth of the recessed shapes 13 and 14 was less than 10 nm, and the strength was remarkably improved as compared with the conventional product. As a result, it has become possible to provide the glass substrate for display 10 that can clear the standard of the strength test in most cases.

Curve A shows, as a comparative example, the strength test result of a display glass substrate manufactured by using another manufacturing method that places importance on flatness so that the dent shape of the film formation surface is 5 nm. Show. The curve A ignores other elements required for the glass substrate for display, and realizes a glass substrate for display having a dent shape of 5 nm or less by using a manufacturing method that places importance on flatness. In actual display glass substrates, there are various conditions that must be cleared in addition to the strength test, and it is important to provide a high-quality display glass substrate as a whole. Often, this is not always a good idea. However, it can be seen that when the recess shape is 5 nm or less, the strength of the glass substrate for display is further improved. Also in the manufacturing method of the glass substrate 10 for display which concerns on Embodiment 1, the depth of a dent shape shall be 5 nm or less and the intensity | strength is further high by devising the kind of abrasive grain and other conditions. It can be seen that it is possible.

Thus, the intensity | strength of the liquid crystal panel 50 can be raised by fully making the depth of the recessed shape 13 and 14 of the film-forming surface 11 of the glass substrate 10 for a display less than 10 nm, and the request | requirement of an intensity | strength test is fully satisfied. Can do. Here, when the thickness of the display glass substrate 10 is t [mm], the display glass substrate 10 having sufficient substrate strength can be obtained when the average breaking load satisfies the equation (1). It has been confirmed.

In the first embodiment, the example in which the display glass substrate 10 is applied to the color filter side glass 15 of the liquid crystal panel 50 has been described. However, the TFT side glass 16, the glass substrate of the organic EL panel, and the cap glass are described. The present invention can be similarly applied to the glass substrate 10 for a plasma display panel. In Embodiment 2 to be described next, an example in which the display glass substrate 10 is used as a cap glass or a glass substrate of an organic EL panel will be described.

FIG. 11 is a diagram showing an example of a cross-sectional configuration of a top emission type organic EL panel 51 using a glass substrate for display according to Embodiment 2 of the present invention. Embodiment 2 demonstrates the example which used the glass substrate for a display of this invention for the organic electroluminescent panel 51 of an organic electroluminescent display.

In FIG. 11, an organic EL panel 51 includes a cap glass 17, an organic EL glass substrate 18, an ITO (transparent electrode) 210, an organic light emitting diode 23, an anode 25, a TFT substrate 41, a seal as a glass substrate. 31. In FIG. 11, a top emission type organic EL panel 51 is shown, which is configured to extract light from the cap glass 17 side.

The organic EL panel 51 has a configuration in which a cap glass 17 and an organic EL glass substrate 18 are disposed to face each other, and a TFT substrate 41 in which a thin film transistor is formed is formed on the organic EL glass substrate 18. On the TFT substrate 41, the anode 25, the organic light emitting diode 23, and the transparent electrode 210 are laminated. A gap is provided between the cap glass 17 and the transparent electrode 210. Further, in FIG. 11, seals 31 for sealing between the cap glass 17 and the organic EL glass substrate 18 are shown at both ends, but the element structure shown in FIG. 11 is for one pixel, In practice, the configuration shown in FIG. And the seal | sticker 31 is provided in a peripheral part so that the pixel number which comprises a screen may be enclosed. In FIG. 11, the element structure for one pixel is shown including the seal 31 for the sake of space.

The strength test is also performed on the organic EL panel 51 of the top emission method having such a configuration. In the test method, as described with reference to FIGS. 2 and 9 of the first embodiment, stress is applied to the cap glass 17 by the pressing jig 60 from the outer surface of the cap glass 17 that is the display surface. . Then, it is tested whether or not the organic EL panel 51 is destroyed. Such a test is performed a plurality of times, and a load at which the organic EL panel 51 is broken is recorded as a breaking load. And what calculated the average of several destruction load is shown as an average destruction load.

Here, in the case of the strength test of the liquid crystal panel 50 described in the first embodiment, a chrome film is formed on the color filter side glass substrate 15, but nothing is formed on the cap glass 17 of the organic EL panel 51. This is different from the strength test of the liquid crystal panel 50 in that no film is formed. That is, there is no factor that weakens the strength of the cap glass 17 unlike the chromium film, and the strength of the pure cap glass 17 is tested. Here, when the thickness of the cap glass 17 is t [mm], it is confirmed that the cap glass 17 having sufficient substrate strength can be obtained when the average breaking load satisfies the equation (1). .

Therefore, in the glass substrate for display according to the second embodiment, the glass substrate for display used as the cap glass 17 is configured to satisfy the expression (1).

Here, in the strength test, since stress is applied from the display surface side of the organic EL panel 51, pressure is applied from above the cap glass 17 in FIG. Therefore, since the crack is most easily generated on the inner surface of the cap glass 17, the strength of the cap glass 17 can be increased by reducing the unevenness on the inner surface of the cap glass 17.

Therefore, in the glass substrate for display according to the second embodiment, the depth of the recessed shape is less than 10 nm in the central region of 20% of the entire area of the surface of the cap glass 17 facing the inside of the organic EL panel 51. The substrate strength shown in the equation (1) is realized. In addition, since the specific structure and manufacturing method of the glass substrate for a display which concern on Embodiment 2 are the same as the content demonstrated in Embodiment 1, the specific description is abbreviate | omitted.

As described above, according to the glass substrate for display according to the second embodiment, it is possible to obtain sufficient test results in the strength test even when the glass substrate for display is used in a top emission type organic EL panel. Become.

FIG. 12 is a diagram showing an example of a cross-sectional configuration of a bottom emission type organic EL panel 52 using a glass substrate for display according to Embodiment 3 of the present invention. The organic EL panel 52 according to the third embodiment is different from the organic EL panel 51 according to the second embodiment in that it is a bottom emission type organic EL panel 52 that extracts light from the organic EL glass substrate 18a side.

The organic EL panel 52 according to Embodiment 3 includes a cap glass 17a, an organic EL glass substrate 18a, a TFT substrate 42, a transparent electrode 220, an organic light emitting diode 24, an anode 26, and a seal 32. In the organic EL 52 according to the third embodiment, the cap glass 17a and the organic EL glass substrate 18a are opposed to each other, and the TFT substrate 42, the transparent electrode 220, the organic light emitting diode 24, and the anode 26 are provided therebetween. The sealed point is the same as that of the organic EL panel 51 according to Embodiment 2, but the shape and arrangement thereof are different. Specifically, the TFT substrate 42 has an opening formed at the center, and is configured to extract light from the lower side of the TFT substrate 42. Further, as the direction of the light output direction is reversed from that of the top emission type organic EL panel according to the second embodiment, the stacking order of the transparent electrode 220, the organic light emitting diode 24, and the anode 26 is reversed. . That is, on the TFT substrate 42, the transparent electrode 220, the organic light emitting diode 24, and the anode 26 are sequentially stacked from below so as to cover the opening of the TFT substrate 42. With this configuration, light can be extracted from the lower organic EL glass substrate 18a side.

Here, in the organic EL panel 52 according to the third embodiment, since the display surface is the organic EL glass substrate 18a, the strength test is performed by applying pressure from the outside of the organic EL glass substrate 18a, that is, the lower surface side. Become. In this case, when the organic EL glass substrate 18a satisfies the average fracture strength of the above-described formula (1), sufficient glass substrate strength can be achieved in the strength test. Therefore, as in Embodiment 3, when a display glass substrate is used for a bottom emission type organic EL panel, the organic EL glass substrate 18a on which the TFT substrate 42 on the display surface side is formed has the formula (1). A glass substrate for display is constructed so as to satisfy.

At this time, as in the second embodiment, stress is most applied to the inner surface of the organic EL glass substrate 18a facing the inside of the organic EL panel 52, so that the inner surface of the organic EL glass substrate 18a is 20% or more of the entire area. The glass substrate for display is configured so that the depth of the dent shape is less than 10 nm in the central region having the area of. The TFT substrate 42 is formed on the inner surface of the organic EL glass substrate 18a. However, since the TFT substrate 42 is not composed of a chromium film, the organic EL glass There is no effect of promoting the destruction of the substrate 18a, and the equation (1) can be applied as it is, as in the top emission method.

In FIG. 12, only one pixel is shown as in FIG. 11, and therefore the seal 32 is inherently present at the periphery of the outer organic EL panel 52. This is the same as in the second mode. Further, FIG. 12 shows an example in which pressure is applied from the lower surface side by the pressing jig 60. However, in an actual strength test, the organic EL glass substrate 18a is on the upper side and the cap glass 17a is on the lower side. The strength test is performed by applying pressure to the outer surface of the organic EL glass substrate 18a from the upper side.

In addition, since the more specific structure and manufacturing method of the glass substrate for display concerning Embodiment 3 are the same as that of the glass substrate for displays demonstrated in Embodiment 1, the detailed description is abbreviate | omitted.

In Example 2, as described in Embodiments 2 and 3, the display glass is assumed on the assumption that the display glass substrate according to this embodiment is used on the display surface side of the organic EL panel of the organic EL display. The strength test of the substrate itself was performed. The strength test method is the same as in FIG. 9 of Example 1, but the glass substrate for display is in a state of only a glass substrate on which no film is formed.

As a condition of the strength test, it was added to a glass substrate for display having a thickness of 0.5 [mm] at a descending speed of 1.0 mm / min. Here, the descending speed indicates the descending speed of the pressurizing jig 60.

Polishing was performed using a slurry containing selenium oxide abrasive grains, which was conventionally performed, and the strength test of a conventional glass substrate for display was performed. As a result, the conventional display glass substrate could not satisfy the formula (1).

Meanwhile, polishing was performed using a slurry containing colloidal silica abrasive grains having an average particle size of 80 [nm], and the strength test of the display glass substrate according to the present embodiment was performed. As a result, the average breaking load was remarkably improved as compared with the conventional glass substrate for display, and the formula (1) was stably satisfied.

Polishing was performed using a slurry containing colloidal silica abrasive grains having an average particle diameter of 20 [nm], and the strength test of the display glass substrate according to the present embodiment was performed. As a result, the average breaking load was remarkably improved as compared with the conventional glass substrate for display. Further, even when compared with the display glass substrate according to the present embodiment, which is polished using a slurry containing colloidal silica abrasive grains having an average particle size of 80 [nm], the average breaking load is improved (1 ) Can be satisfied more stably.

Thus, as shown in Example 2, the display glass substrate according to the present embodiment has much higher substrate strength than the conventional display glass substrate, and is not formed at all. It can be seen that good test results can be obtained even when a strength test is directly performed on a non-display glass substrate.

In the first embodiment, the content corresponding to the strength test of the liquid crystal panel 50 will be mainly described. In the second and third embodiments, the content corresponding to the strength test of the organic EL panels 51 and 52 will be mainly described. However, the present invention is not necessarily related to the strength test, and can sufficiently respond to various demands for increasing the flatness of the glass substrate 10 for display, and can also be used for such applications. .

The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be added to the above-described embodiments.

Although this application has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.
This application is based on a Japanese patent application filed on October 26, 2009 (Japanese Patent Application No. 2009-245939), the contents of which are incorporated herein by reference.

The present invention can be used for flat display panels of flat panel displays such as liquid crystal panels, organic EL panels, and plasma display panels.

DESCRIPTION OF SYMBOLS 5 ... Glass raw material 6 ... Molten glass 7 ... Glass substrate 10 ... Display glass substrate 11 ... Film-forming surface 12 ... Central area | region 13, 14 ... Recessed shape 15 ... Color filter side glass substrate 16 ... TFT side glass 17, 17a ... Cap Glass 18, 18a ... Organic EL glass substrate 20 ... Black matrix 210, 220 ... Transparent electrode 23, 24 ... Organic light emitting diode 25, 26 ... Anode 30 ... Color filter 40 ... Amorphous silicon film 41, 42 ... TFT substrate 50 ... Liquid crystal panel 51, 52 ... Organic EL panel 60 ... Pressure jig 61 ... Receiving jig 70 ... Protective layer 80 ... Float glass manufacturing equipment 81 ... Melting kiln 82 ... Float bath 83 ... Gas supply port 84, 88 ... Heater 86 ... Draw roll 87 ... Slow cooling furnace 90 ... Molten tin 100, 101, 102, 300 ... Polishing device 114 ... Film frame 116, 122 ... Stage 118, 120 ... Polishing stage 130, 131 ... Slurry supply hole 150 ... Polishing head 152 ... Carrier 156 ... Spindle 158, 160 ... Polishing pad 202 ... Air supply path 204 ... Valve 206 ... Air pump 250, 252, 254 ... Conveying device 256 ... Elevating mechanism 258 ... Slider 270 ... Guide rail 312 ... Suction sheet 314 ... Circular polishing tool

Claims (13)

1. A glass substrate on the display surface side of a flat panel display,
   A glass substrate for a display, wherein the depth of the concave shape is less than 10 nm in a central region having an area of 20% or more of the entire area of the surface facing the inside of the flat panel display.
2. The average breaking load when a load is applied from the surface facing the outside of the flat panel display is 600 × (t / 0.5) ² N or more when the plate thickness is tmm. The glass substrate for a display according to claim 1.
3. The flat panel display is a liquid crystal display,
   The display glass substrate according to claim 1, wherein the display surface side is a color filter side.
4. The flat panel display is an organic EL display,
   The display glass substrate according to claim 1, wherein the display surface side is a cap glass side.
5. The flat panel display is an organic EL display,
   The display glass substrate according to claim 1, wherein the display surface side is a TFT glass substrate side.
6. A method for producing a glass substrate for display used in a flat panel display,
   Forming a glass substrate;
   Setting one side of the glass substrate as a polishing surface, and installing the glass substrate in a polishing apparatus that performs polishing using abrasive grains;
   Polishing the polished surface of the glass substrate using abrasive grains having an average particle size of 80 nm or less, and a method for producing a glass substrate for a display.
7. The method for producing a glass substrate for display according to claim 6, wherein the abrasive grains contain colloidal silica.
8. The method for producing a glass substrate for display according to claim 7, wherein the abrasive grains have an average particle diameter of 20 nm or less.
9. The method for producing a glass substrate for display according to any one of claims 6 to 8, wherein in the step of forming the glass substrate, the glass substrate is formed by a float method.
10. The flat panel display is a liquid crystal display,
    The method for manufacturing a glass substrate for display according to any one of claims 6 to 9, wherein the polishing surface is a color filter forming surface of a color filter substrate.
11. The method for manufacturing a glass substrate for a display according to claim 10, wherein the color filter forming surface is a surface on which a black matrix composed of a chromium film is formed before the color filter is formed.
12. The flat panel display is an organic EL display,
    The method for producing a glass substrate for a display according to any one of claims 6 to 9, wherein the polished surface is an inner surface of a cap glass.
13. The flat panel display is an organic EL display,
    The method for producing a glass substrate for a display according to any one of claims 6 to 9, wherein the polished surface is an inner surface of a TFT glass substrate.

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