KR20070026462A - Separation method of flat glass for flat panel display, flat glass for flat panel display and manufacturing method thereof - Google Patents

Abstract

Plate glass with a maximum dimension of internal defects of 30 µm or more and a maximum depth or a maximum height of 0.1 µm of the light-transmitting surface of a part of the light-transmitting surface corresponding to the position of the internal defects shall be regarded as a defective product. Screening as.

Description

Method for sorting flat glass for flat panel display, flat glass for flat panel display and manufacturing method thereof {METHOD FOR SORTING PLATE GLASS FOR FLAT PANEL DISPLAY, PLATE GLASS FOR FLAT PANEL DISPLAY AND METHOD FOR MANUFACTURING THE SAME}

TECHNICAL FIELD This invention relates to the flat glass for flat panel displays used as a structural member of a flat panel display.

In the flat panel display device, with the progress of various display systems, such as a liquid crystal and a plasma, the improvement of the image quality and the expansion of a display screen have progressed rapidly. For this reason, among these technical innovations, various improvements and improvements have also been made to the plate glass constituting the flat panel display, and there has been a continuous demand for higher demands. What is important as a technique regarding the flat glass for flat panel displays is the improvement of the glass material required for realizing a function as an electronic component, and the improvement of the appearance quality which greatly affects the performance of a flat panel display. Although the glass material and the appearance quality depend on each other, in particular, the appearance quality of the plate glass is required to observe a moving picture, a high-definition image, etc. through the light-transmitting surface. For example, in the case of the typical TFT plate glass used for liquid crystal use, the quality of the scratches and stains on the surface thereof is not confirmed by visual inspection under illumination of 10,000 lux. In addition, high quality is often required in terms of surface precision such as bending and bending of plate glass.

As described above, since the plate glass used for the liquid crystal substrate is required to have high surface accuracy, the polishing process of the plate glass surface has been performed as described in Patent Literature 1, but the advancement of various technologies for directly forming the plate glass from the molten glass is performed. As a result, unpolished plate glass is often used as it is. In addition, as described in Patent Literature 2 and Patent Literature 3, internal defects such as bubbles and foreign matters in the plate glass have been greatly improved by changing the material, raw material composition, and the like of the plate glass.

Patent Document 1: Japanese Patent Application Laid-Open No. 2000-127009

Patent Document 2: Japanese Patent Publication No. 2003-137591

Patent Document 3: Japanese Patent Application Laid-Open No. 2004-91244

Improvements that have been made to flat glass for flat panel displays have been made under the policy of employing a slight improvement in the performance of flat panel displays such as display quality improvement and high definition. And, according to this way of thinking, a lot of time has been spent to realize the high demanded quality required for flat glass. For this reason, the plate glass quality used for a flat panel display may be far beyond the grade sufficient as a flat panel display with respect to the specific dimension, function, and cleanliness of a plate glass, and it can also be said to be such an excess on the other hand. The quality which has become one of the causes which causes a shortage in supply to the market of flat glass for flat panel displays.

For example, in the manufacturing process of a liquid crystal display using a TFT (thin film transistor), various thin film layers, such as amorphous silicon, an insulator, and a semiconductor, are formed on a thin alkali-free glass substrate, and pattern processing is performed, and TFT or liquid crystal drive is performed. TFT process (also referred to as TFT array process and substrate process) for forming display electrodes for wires and wiring, and panel process (also referred to as cell process) in which liquid crystal is injected into the gap between the TFT substrate and the color filter substrate. And a module process (also referred to as a mounting process) that connects an integrated semiconductor circuit such as a driving IC to a panel and installs a backlight. Among these series of processes, in particular, the TFT array process is similar to various manufacturing processes in which a silicon single crystal used as the substrate material of the LSI is used. For this reason, the idle idea of requesting the grade which is requested | required also for plate glass like the silicon single crystal used as a base material in a semiconductor production process arises. However, the critical difference between the display plate glass and the silicon single crystal substrate is the difference in its external size, that is, the difference in volume, and overcomes problems such as charging phenomena generated on the basis of this difference, so that one sheet glass can fit the required quality. Until energy is given to various physical functions to improve the surface precision and cleanliness, and to clear the required quality of various internal defects, the energy required is enormous, and excessive response is required.

The internal defects of the flat glass for flat panel displays include bubbles and foreign substances, but in reality, even when a small internal defect exists in the glass, it is possible to block the image of the flat panel display, If the wiring structure formed on the glass substrate is disconnected for driving, the flat panel display device does not cause a serious problem that the normal operation does not work. However, up to now, only those that can meet the strict standard by making all of them destructive for internal defects that can be identified regardless of whether or not they are acceptable have been supplied as products of flat glass for flat panel displays.

On the other hand, since such excessive quality was realized, the product yield of plate glass fell remarkably, and the problem that it could not supply a sufficient quantity of plate glass enough to respond to the demand from the market arises. In addition, inspections performed to dispose of all panes with identifiable defects and disposal of large-scale panes require considerable effort, and are in a state of difficulty in terms of efficiently managing human assets required for manufacturing. It was.

MEANS TO SOLVE THE PROBLEM In view of such a situation, this inventor provides the flat glass for flat panel displays, the sorting method, and the manufacturing method which have sufficient functions and performance in practical use, and are excellent as a plate glass used for various flat panel display apparatuses. Let's make it a task.

That is, the method for screening a flat glass for flat panel display of the present invention is a method for screening internal defects of a plate glass having a light-transmissive surface and sorting good and defective products, wherein the maximum dimension of internal defects is 30 µm or more, and The glass plate having a maximum depth or a maximum height of 0.1 µm or more on the light-transmitting surface of the partial region of the light-transmissive surface corresponding to the position is regarded as a defective product, and other plate glass is selected as a good product.

As internal defects of plate glass, undissolved residual raw materials generated when melting and manufacturing the glass at high temperature, metals such as platinum generated from the furnace walls of the refractory container in which the molten glass resides, poorly soluble foreign materials such as refractory materials, or vitrification reactions And glass having heterogeneous composition, also referred to as knots, stria, etc., generated by gas generated from raw materials and the like. In addition, the "internal defect" does not include surface damage such as cracks, scratches, or scratches present on the surface, end surface, or the like of the plate glass. That is, "internal defect" as used in this specification means only the defect which exists in the inside of plate glass.

MEANS TO SOLVE THE PROBLEM As a result of many years of research about flat glass for flat panel display uses, the internal defect clearly distinguished in the state which mounted on the flat panel display which is an image display apparatus blocks the pixel of a flat panel display. I realized that it is. Such internal defects become a problem when they do not block all of the pixels but have an effect of greatly reducing the luminance of the pixels. However, except in this case, internal defects do not reduce the performance of the product. Such internal defects may not be recognized by simple visual inspection in the state of flat glass.

And while investigating the defective product in a plate glass manufacturing process, specifying the property of the internal defect and making only what is called "the internal defect which does not reduce product performance", the flat glass for flat panel displays previously produced with excessive quality. The inventors found that the quality required by the customer can be sufficiently satisfied, and the product yield of the plate glass can be improved.

In other words, even if the internal defect of the plate glass has a maximum dimension of 30 µm or more, and the internal defect blocks a plurality of pixels, the internal defect may be considered to be equivalent to glass in terms of refractive index and transmittance. If it is not blocked, there is no recognition of an internal defect. And in that case, even visual inspection in the state of plate glass is not recognized. On the other hand, for example, in the internal defect inspection of plate glass, such as for liquid crystal use, edge light is used and the inspection may be performed by detecting the scattered light in the internal defect, and when the inspection is performed using light beams from various directions in this way. There is a tendency that excessive inspection is performed, and even if it is an internal defect which does not reduce the performance of a product originally, it may be called a defective product. However, when judging good and defective products by the screening method of the present invention, for example, inspection by transmitted light is performed to evaluate in a state close to the use state of the original product, and only the product performance is not reduced. It becomes possible to employ.

When the internal defect itself transmits visible light, it is the interface between the internal defect and the glass that obstructs the light beam, and only the interface identified in a curved shape when viewed from the side of the transparent glass surface. For this reason, if the interface between the glass and the internal defects exists in a positional relationship that fits exactly within one pixel, that is, when the dimension of the internal defects is small by that, it also depends on where the internal defects exist in the thickness direction of the plate glass. Internal defects increase the risk of crushing one pixel. And according to the research of the present inventors, when an internal defect exists in the specific position of a glass plate thickness, and the dimension of an internal defect is smaller than 30 micrometers, the situation which crushes one pixel tends to arise, and it is made as a display apparatus. When one of the pixels is configured to display an image, one pixel is crushed, and as a result, it is recognized that there is an internal defect in the display screen of the display device. That is, in this invention, it is important that the dimension is 30 micrometers or more about the internal defect in the plate glass sorted as a defective article. In addition, defects may not be recognized because the light is introduced behind the internal defects due to diffraction around the internal defects, making it difficult to identify the internal defects themselves.

During the investigation of the above phenomenon, an internal defect having a dimension of 30 µm or more exists, and a part of the light-transmitting surface of the plate glass closest to the internal defect location may be raised in a convex shape due to the internal defect. In the case of or being concave in shape, it has been found that the recognition rate of internal defects increases after being assembled as a display. Then, about the convex bumps and concave recesses of the part of the light-transmitting surface, the maximum dimension (maximum height, maximum depth) is measured by contact or non-contact surface roughness measuring method of glass surface. It turned out that it is more than 0.1 micrometer with respect to a light emitting surface.

That is, the method for sorting the flat glass for flat panel display of the present invention has an internal defect of the maximum dimension of 30 µm or more with respect to the plate glass having a light-transmitting surface, and also corresponds to the position of the internal defect (closest to the internal defect). Part of the area where the light-transmitting surface is made of convex bumps having a maximum height of more than 0.1 µm with respect to the light-transmitting surface or concave pit having a maximum depth of more than 0.1 µm with respect to the projecting surface is defective. It is set as the good glass other than that. And this sorting method changes according to the size and use of a plate glass, Preferably, the part of the light-transmitting surface corresponding to the position of the internal defect of the maximum dimension 80 micrometers or more (closest to the internal defect) with respect to one sheet glass, The unevenness of the plate glass surface closest to the internal defect with respect to the light-transmissive surface is selected as a defect having a dimension exceeding ± 0.1 μm with respect to the light-transmissive surface of the plate glass, and more preferably, the maximum dimension 100 for one sheet glass. The part of the light-transmitting surface corresponding to the position of the internal defect larger than or equal to μm, and the unevenness to the surface of the plate glass closest to the internal defect relative to the light-emitting surface exceeds ± 0.08 μm with respect to the light-emitting surface of the plate glass. It is to sort out what has a dimension as a defect, More preferably, on the inside defect of the maximum dimension of 150 micrometers or more with respect to 1 sheet glass Part of the light-transmissive surface corresponding to (closest to its internal defect) has a dimension in which the unevenness of the plate glass surface closest to the internal defect with respect to the light-transmissive surface has a dimension exceeding ± 0.05 μm with respect to the light-transmissive surface of the plate glass. Most preferably, a part of the light-transmitting surface corresponding to the position of the internal defect (closest to the internal defect) having a maximum dimension of 180 µm or more for one sheet glass is closest to the internal defect with respect to the light-emitting surface. The unevenness | corrugation with respect to the plate glass surface has a dimension over +/- 0.03 micrometer with respect to the light transmission surface of a plate glass, and selects as defect.

In addition, the method for screening a flat glass for flat panel display according to the present invention is a method for screening internal defects of a plate glass having a light-transmissive surface to sort good and defective products, the maximum dimension of the internal defect being 30 µm or more, and the position of the internal defects. It is characterized in that the plate glass having a distance from the light-transmitting surface partial region corresponding to to the internal defect is less than 0.01 μm as a defective product, and other plate glass is selected as a good product.

Here, the "distance from the part of the light-transmitting surface corresponding to the position of the internal defect to the said internal defect" progresses in the direction perpendicular to the light-emitting surface from the part of the light-transmitting surface closest to the internal defect, It means the shortest distance to the vertical (shortest vertical).

The vertical shortest distance from the partial region of the light-transmitting surface to the internal defect is influenced by the properties of the internal defects existing in the plate glass, the composition of the plate glass, the forming method of the plate glass, and the like. The influence on the surface shape change of is small. Therefore, the said vertical shortest distance used as the selection criteria of defective products is preferably less than 0.03 µm, more preferably less than 0.05 µm, still more preferably less than 0.07 µm, and most preferably less than 0.09 µm.

In addition, the flat glass for flat panel display of the present invention has a light-transmissive surface, an internal defect is present, a maximum dimension of the internal defect is 30 μm or more, and a light-transmitting surface of a part of the light-transmitting surface corresponding to the position of the internal defect. It is characterized in that the maximum depth or the maximum height is less than 0.1㎛.

The flat glass for flat panel displays of this invention determines the upper limit of the maximum dimension of an internal defect by the dimension of a plate glass, and the upper limit is the end side dimension of the short side, ie of a flat glass, with respect to the transmissive surface which has a rectangular shape of a plate glass. Up to 90% of the length of the short side of the transmission surface. The presence of an internal defect having a length exceeding 90% of the short side dimension on the short side is not preferable because, for example, the problem of the strength of the plate glass is increased even if there is no problem in refractive index or transmittance optically. And in order to make the plate glass which high mechanical property was ensured, it is preferable that there is no internal defect of length more than 80% of the dimension of the edge of a short side, More preferably, it is 70%, More preferably, 50%, Furthermore, More preferably no internal defects of length exceeding 30%, most preferably 10%.

Here, the internal defect is for example a bubble, that is, a bubble containing any gas or a vacuum bubble containing no gas. For a bubble to include any gas, as the kind of the gas, the oxygen, carbon dioxide and carbon monoxide, Knox (NO _X), nitrogen, chlorine, bromine, hydrogen, and argon, helium, neon, xenon, steam, socks (SO _X) And sulfurous acid gas. Moreover, in the case of a vacuum bubble, the component at the time of bubble formation may be precipitated as a solid in some state in the inside wall of a bubble.

The foam constituting the internal defect has a shape in which the surface of the foam is close to a spherical shape with little variation in the radius of curvature, is elongated in one direction, and is a cross section perpendicular to the elongated direction while being elongated in one direction. There are flat and various forms. However, the size of the curvature of the bubble outer surface overlapping the neighboring pixels may be different, rather than the outer surface positions of bubbles having the same small curvature overlapping the neighboring pixels. From this point of view, the foam surface is preferably one extending in one direction rather than close to a spherical shape.

Alternatively, the above internal defects may be solid foreign materials, for example. The solid foreign material as an internal defect does not have transparency to visible light like foam, but has a shielding property, for example, it does not have transparency such as fine foreign matter such as refractory material or platinum or residual foreign material of a glass raw material.

Moreover, it is preferable that the flat glass for flat panel displays of this invention has a light transmission surface on both surfaces, and the light transmission surface has an area of 20x10 <^5> mm <2> or more in a double surface total. In a more preferable aspect, one light transmitting surface has an area of 10 × 10 ⁵ mm 2 or more.

As a plate glass which has such an area, the plate glass which has the transversal dimension of the transmissive surface of 1000 mm x 1200 mm, 1100 mm x 1250 mm, 1370 mm x 1670 mm, and 1500 mm x 1800 mm, for example corresponds. It is preferable that the thickness dimension of this plate glass is 0.7 mm or less.

In addition, the flat glass for flat panel displays of this invention is produced by dividing into two or more sheets, for example from a parent glass. A parent glass is also called a disc, mother glass, a base material, etc.

About the dimension of the parent glass, it is not specifically limited. In addition, there are no particular limitations on the dimensions, varieties, and the like of the display device manufactured from one sheet of the parent glass. Therefore, you may manufacture the display device of a different dimension from one sheet of parent glass, and may manufacture the display device which has the same dimension.

The flat glass for flat panel displays of this invention is suitable for a liquid crystal display device.

Regardless of the difference between the liquid crystal elements and differences in the image display system, for example, the liquid crystal can be used irrespective of the type of nematic liquid crystal, smectic liquid crystal, cholesteric liquid crystal, or the like. Can be used regardless of the difference.

Moreover, the flat glass for flat panel displays of this invention is suitable also for a TFT display apparatus.

A TFT display device is a liquid crystal display display by a thin film transistor system, and as long as it is a TFT display device, what used polycrystalline Si and amorphous Si as a semiconductor material can be used.

Moreover, the plate glass for flat panel displays of this invention is suitable also for an inorganic or organic electroluminescent display.

Here, the inorganic or organic EL display is a display which enables light emission by applying a low voltage by depositing an inorganic or organic material which emits light when a voltage is applied to a glass substrate and applying a voltage capable of emitting such a light emitter. . As an inorganic EL display, what used light emitting bodies, such as zinc sulfide, was used, and as an inorganic EL display, what used light emitting bodies, such as diamines, was used.

Moreover, the flat glass for flat panel displays of this invention is suitable also for a field emission display.

Here, in the field emission display, the display principle of the display is that the minute electrodes on the glass substrate are arranged in the lattice form as many as the pixels, and are several mm away from their respective planar electron emission sources (emitters). It is a flat display device based on the same principle as CRT (Brown Tube) which emits electrons toward a phosphor on a glass substrate facing each other and emits electrons by colliding with the phosphor. In addition, there are various types of electron emission sources, but in addition to the type of spin type, which has been developed in the related art, recently there are new types such as Surface-conduction Electron-emitter Display (SED).

And the flat glass for flat panel displays in this use targets the flat glass which comprises the front of an apparatus, when it transmits information, such as an image, and is assembled as a field emission display among the two sheets of glass used for a field emission display. It is to be done. Further, due to the nature of the display, the dimensions of the pixels, and the like, the maximum dimension of internal defects has a condition that the maximum depth or the maximum height with respect to the light emitting surface of a part of the light emitting surface corresponding to the position of the internal defect is 0.1 占 퐉 or less. As long as it is, it may be 100 micrometers or more, Preferably it may be 150 micrometers or more, More preferably, it may be 180 micrometers or more, Most preferably, 300 micrometers or more may be sufficient.

In addition, the flat glass panel for flat panel display of the present invention has a light-transmissive surface, an internal defect is present, a maximum dimension of the internal defect is 30 µm or more, and an internal defect is formed from a part of the light-transmitting surface corresponding to the position of the internal defect. The distance to reach is characterized by being 0.01 μm or more.

Here, the "distance from the part of the light emitting surface corresponding to the position of the internal defect to the said internal defect" is a direction perpendicular to the light emitting surface from the part of the light transmitting surface closest to the internal defect as described above. It is the shortest distance (the shortest vertical length) from going on to internal defect. In the plate glass for flat panel displays of this invention, the upper limit of the said vertical minimum distance and the upper limit of the largest dimension of the internal defect in the plate thickness direction are determined by the plate thickness dimension of plate glass. Preferably, the vertical shortest distance is 50% or less of the plate thickness, and the maximum dimension in the plate thickness direction of the internal defect is preferably 30% or less of the plate thickness. If the maximum dimension of the internal defect in the plate thickness direction exceeds 30% of the plate thickness dimension, there is a high possibility that the mechanical strength of the plate glass will be disturbed. From this point of view, the maximum dimension in the plate thickness direction of the internal defects is preferably 25% or less of the plate thickness dimension, more preferably 20% or less, even more preferably 18% or less, and most preferably 15% or less. It is to be.

In addition, the flat glass for flat panel displays of this invention is produced by dividing into two or more sheets, for example from a parent glass. A parent glass is also called a disc, mother glass, a base material, etc.

Moreover, it is preferable that the flat glass for flat panel displays of this invention has a linear internal transmittance of 90% or more with respect to visible light of wavelength 450 nm-650 nm in the part containing an internal defect. Moreover, especially in the plate glass used for a liquid crystal display, it is preferable to have a linear internal transmittance of 90% or more with respect to the visible light of wavelength 400 nm-800 nm in the part containing an internal defect. This is a display which a liquid crystal display displays using the light of external light sources, such as a backlight, and is due to low utilization efficiency of light.

Here, the linear internal transmittance is, for example, cut into a rectangular shape of 20 mm square, which can measure the plate glass to be a sample piece, and the reference glass of the double beam spectrophotometer (thin plate glass for flat display and measurement) (Glass of the same composition), and in the plate thickness area | region equivalent to 1-5 mm on all sides containing the location where the internal defect of the said sample piece exists, it is the range of wavelength 450.0nm to wavelength 650.0nm, or 400 to 800nm. It can measure and obtain | require at a scanning speed of 0.3 nm / sec using light. Of course, the plate glass used as a sample uses the thing which has not coat | covered thin films etc. to the light transmission surface.

In addition, plate glass for a flat panel display of the present invention is preferably a silicate glass containing SiO ₂ 95% by mass or less, Al ₂ O ₃ 5% by mass or more.

Moreover, it is preferable that the plate glass for flat panel displays of this invention is an alkali free glass.

Here, an alkali free glass means that elements, such as sodium, potassium, and lithium, which are alkali metal elements in a glass composition, become 0.1 mass% or less in oxide conversion. The flat glass for flat panel displays of this invention can employ | adopt the glass composition required from the use, For example, in the TFT liquid crystal display which drives a pixel with a thin film transistor (TFT), the alkali component contained in glass is a liquid crystal. There is a risk of impairing the function of the display, and the desired function can be realized by setting the composition which does not contain an alkali metal element as the composition of the plate glass, that is, an alkali free glass composition.

In addition to the above, it is preferable that the flat glass for flat panel displays of this invention contains 5 mass% or more of alkaline earth elements in oxide conversion. Moreover, it is preferable that content of an alkaline-earth metal element is not low 10 mass% or more with respect to content of alumina. Since the chemical durability of glass can be maintained by setting it as such a composition, it has high durability with respect to various chemical liquids, such as acid, hydrofluoric acid, and alkali used in the process of manufacturing a liquid crystal display, for example, and also in long time high humidity environment, etc. It is possible to make the glass material which is hard to cause trouble even in the use of.

A flat panel display glass of the present invention, in addition to the above, it is preferable to contain As ₂ O ₃ more than 0.1% by mass. This is necessary for the environment, and becomes important in processing steps such as use environment and reuse of plate glass.

From the viewpoint as described above, for example, it is a flat panel display glass of the present invention, SiO ₂ 45~75% by weight percentages, Al ₂ O _3% 6~20, 7~30% RO (RO = MgO + CaO It is preferable to set it as the glass material which has a composition like + ZnO + SrO + BaO).

In addition, plate glass for a flat panel display of the present invention, in order to realize a high transmittance, it is preferable that the transition of Fe ₂ O ₃ or Cr ₂ O ₃ in the glass composition kept low the content of the metal oxide, specifically a transition metal oxide Is preferably 500 ppm or less, more preferably 300 ppm or less, and even more preferably 200 ppm or less.

Moreover, since it is preferable that the plate glass for flat panel displays of this invention is lightweight, it is preferable that the density is 2.6 g / cm <3> or less. And when paying attention to the deformation | transformation with respect to external force, it is preferable that the value which divided the Young's modulus by the density is 28 dl / g * cm <^-3> or more.

Moreover, it is preferable that the plate glass for flat panel displays of this invention was produced by the extending-molding method.

Here, the stretch molding method is a method of realizing a predetermined surface precision, sheet thickness, and sheet area by applying a drawing force to the glass through a heat-resistant device such as a roll when forming a molten glass in a high temperature state by a desired molding method. . Examples of the stretch molding method include a slot down draw molding method, an overflow down draw molding method, a roll out molding method, and a float molding method.

Moreover, the manufacturing method of the plate glass for flat panel displays of this invention is the shaping | molding process of shape | molding a molten glass to plate shape by an extension molding method, and obtaining the lyophilic glass which has a translucent surface, the inspection process which examines the internal defect of a lyophilic glass, A cutting step of cutting the parent glass having inspected the internal defects to obtain two or more sheets of glass, and in the inspection step, the maximum dimension of the internal defects is 30 µm or more, and the partial area of the light emitting surface corresponding to the position of the internal defects When a defective portion having a maximum depth or a maximum height of more than 0.1 μm on the light transmitting surface is detected, the parent glass is cut to remove the defective portion in the cutting process.

Here, the stretch molding method in the molding step is a method of forming a sheet glass shape by applying a stretching force to the molten glass in a high temperature state, hot forming as described above, and can achieve the desired plate thickness and the required function. . The inspection process can be performed using, for example, an apparatus equipped with an electronic device or the like that has a function of mapping internal defect positions in the plate glass and can record information such as dimensions of the internal defects as digital information, or Can be implemented by adopting an analog method by utilizing visual inspection by a manufacturing expert. In addition, an inspection process may be performed with respect to the plate glass at the time of a shaping | molding process, and may be performed with respect to the plate glass cooled to room temperature after a shaping | molding process.

In the cutting process, a defect having a maximum dimension of internal defects of 30 µm or more and having a maximum depth or a maximum height of 0.1 mu m or more with respect to the light emitting surface of the partial area of the light emitting surface corresponding to the position of the internal defects was detected in the inspection process. In this case, it is a process of cut | disconnecting a glass plate so that the said defective part may be excluded based on the information obtained from this inspection process. For example, in the cutting process, a plurality of regions corresponding to the area of the plate glass to be obtained should be obtained so as to avoid a portion detected as defective in the inspection process and to obtain a large number of sheets of glass that satisfy the required shape and dimensions without waste. It selects from and cuts out the parent glass along the outline of this selected multiple area | region.

In the above cutting step, when the predetermined number of sheets of glass are cut from the parent glass, unselected regions remain in the glass. Although the remaining plated glass can be discarded as it is, a plate of small size can be obtained from the remaining plated glass for effective use of the glass material. This can be performed by repeating the above cutting process. That is, a plurality of regions corresponding to the area of the plate glass to be obtained are selected from the rest of the parent glass, so as to avoid a portion detected as defective in the inspection process and to obtain a large number of sheets of glass that satisfy the required shape and dimensions without waste. By cutting the remaining parent glass along the contour of the selected multiple regions, it is possible to obtain a plate glass having a smaller size than the first plate glass. And if this cutting process is repeated further, the plate glass of a smaller size can be obtained. In addition, the inspection process may be performed only in the manufacturing process of the first plate glass, and the detection information may be used in the subsequent repetitive cutting process, and the internal defect may be caused by the characteristics required for the plate glass obtained in the subsequent repetitive cutting process. It may be carried out every time before changing the allowable reference value and performing the subsequent repeated cutting process.

The cutting method in a cutting process is not specifically limited, For example, methods, such as a mechanical scribe and a laser scribe, may be employ | adopted, and the cutting apparatus provided with a diamond grindstone, etc., and various cutting machines may be used. . Moreover, you may use together several these cutting methods.

As the stretch molding method in the molding step, an overflow down-draw method can be adopted.

The overflow down-draw method is a method of overflowing the molten glass from the trough structure of a heat resistant agent, extending | stretching the overflowed molten glass below the trough structure, and manufacturing a plate glass.

Here, the structure and material of the trough structure are not specifically limited as long as the dimension and surface precision of plate glass are made into the desired state, and the quality which can be used for a flat panel display can be implement | achieved. In addition, in order to perform extending | stretching downward, what kind of method may be applied to plate glass. For example, a method of rotating and stretching a heat-resistant roll having a sufficiently large width in contact with the plate glass may be employed, or a method of drawing a plurality of pairs of heat-resistant rolls by contacting only near the end face of the plate glass and stretching. good.

In addition, the inspection of the internal defect of the lyophilic glass in an inspection process can be performed by irradiating at least one of visible light, a laser beam, an electron beam, and an ultrasonic wave to a lyophilic glass.

For example, by irradiating any one or more of visible light, laser light, electron beam, and ultrasonic waves to one light emitting surface of the plate glass, the light is incident from the surface, and is emitted from the other light emitting surface, and the energy of the emitted light or sound wave is emitted. Internal defects can be detected by measuring the scattered rays. Specifically, a solid-state imaging device can be used as the light receiving device for receiving the emitted or scattered light rays. In addition, an inspection process does not prevent combined use of inspection methods other than the above. Moreover, it is preferable that the test process is performed at the temperature of plate glass above room temperature. The inspection step may be to specify the position (distribution) of internal defects in the plane direction of the plate glass, or to specify in both directions of the plane direction and the plate thickness direction, and also to determine the positioning method and the plate thickness direction in the plane direction. Another positioning method may be employed as the positioning method.

(Effects of the Invention)

ADVANTAGE OF THE INVENTION According to this invention, the plate glass for flat panel displays which have sufficient functions and performance in practical use, and is excellent in yield as plate glass used for various flat panel display apparatuses can be provided.

1 is a perspective view showing a plate glass for a flat panel display according to an embodiment.

2: is explanatory drawing of the vicinity of the translucent surface of the flat panel display plate glass, (A) part shows a partial perspective view and (B) part shows a partial sectional drawing.

3 is a partial cross-sectional view of the vicinity of a light transmitting surface of the flat glass for flat panel display according to the comparative example.

<Description of Symbols for Major Parts of Drawings>

1, 10: plate glass for flat panel display 2: light emitting surface

3: end face 4: ridge

K: Internal defect L: Maximum dimension

H: distance from the light transmitting surface to the internal defect

T: maximum height of the light emitting surface of a part of the light emitting surface corresponding to the internal defect

W: distance from end face to internal defect

Below, the flat glass for flat panel displays obtained by the sorting method of the flat glass for flat panel displays of this invention, and its manufacturing method are demonstrated based on an Example.

Example 1

The external appearance of the flat glass for flat panel displays of a present Example is shown in FIG. 2, the enlarged view with respect to the light transmission surface vicinity of plate glass is shown. The flat glass for flat panel display 1 of this embodiment has the light-transmitting surface 2 of 1370 mm x 1670 mm on both sides, has the rectangular external appearance whose plate | board thickness is 0.7 mm, and the curvature of the plate glass 1 is 300 The curvature which is 0.45 mm or less with respect to the dimension of mm, and confirmed as unevenness | corrugation of the period from 5 mm to 20 mm or less is less than 0.2 micrometer, and is 0.1 mm or less with respect to the measurement length with the plate thickness tolerance of 300 mm in surface. Moreover, the chamfering process of 0.2 mm is given to the ridgeline 4. The glass material of the plate glass 1 is expressed in terms of mass% in terms of oxide, and 60% SiO ₂ , 15% Al ₂ O ₃ , 10% B ₂ O ₃ , and RO (R = Mg + Ca + Sr + Ba + Zn). ) 14%, Sb ₂ O ₃ 1% alkali-free glass composition, the content of the alkali component is 0.05% or less in terms of oxide, the density of the plate glass is 2.49g / ㎠. Moreover, as a thermal property of this plate glass, the strain point is 660 degreeC and the temperature equivalent to high temperature viscosity 10 ^2.5 dPa * s is 1570 degreeC.

This plate glass 1 has one bubble defect K whose maximum dimension L is 120 micrometers as an internal defect, 20 mm of distances W from the end surface 3 of the plate glass 1, and one light transmission. At the position of the depth H of 0.4 mm from the surface 2, it exists in the aspect extended in the parallel direction with respect to both the end surface 3 and the light transmission surface 2. As shown in FIG. The gas composition of foam is 25 mass% of carbon dioxide, 73 mass% of nitrogen, and 2 mass% of oxygen. And in order to evaluate the surface property of the plate glass light transmission surface (light transmission surface partial area) of the most recent location where this bubble exists, as a result of measuring the unevenness | corrugation of the light transmission surface partial area by a laser measuring device, The maximum height T was 0.01 µm, and it was found that there was no problem.

Although this plate glass 1 is used for liquid crystal use, an inorganic, or an organic electroluminescent display use, in order to evaluate the performance of this plate glass, it uses the manufacturing process of a liquid crystal panel in the manufacturing line of a liquid crystal panel, and assembles a panel, and evaluates it. As a result, it turned out to be the same evaluation result as the conventional product, and the quality was not confirmed with respect to display performance, such as an image.

In addition, in order to evaluate the transmittance | permeability with respect to the internal defect presence point of this plate glass, the plate glass sample of 20 mm of one sides included the periphery of the location corresponded to an internal defect, and disassembled the plate glass once assembled as a panel. I wrote the section. Reference glass having a thickness of 0.7 mm on the reference side of the double beam spectrophotometer in the range of wavelength 450.0 nm to wavelength 650.0 nm for the transmissive surface rectangular region of 1 to 5 mm square containing the internal defect presence point of the sample piece. The measurement was carried out using measurement conditions of a scanning speed of 0.3 nm / sec. In this reference glass, a very small amount of impurities which may lower the transmittance of visible regions such as Fe ₂ O ₃ were used, and it was confirmed in advance from the transmittance and the refractive index of this glass that the internal transmittance was almost 100%. As a result, it was confirmed that the transmittance of 95% or more was observed for the wavelength range from the wavelength of 450.0 nm to the wavelength of 650.0 nm.

[Comparative Example]

3, the enlarged view of the vicinity of the translucent surface of the plate glass which is a comparative example is shown. The glass plate 10 of the comparative example shown in FIG. 3 is also used for a flat panel display similarly to the example, but as shown in FIG. 3, one internal defect K having a maximum dimension of 40 μm is formed from an end surface of the plate glass 10. Distance W (see Fig. 2) is 40 mm in a direction parallel to both the end face 3 and the light emitting surface 2 at a position of a depth H of 0.008 μm from one light emitting surface 2. It is in an extended form. And if the maximum height T of the light-transmitting surface of the part of the light-transmitting surface corresponding to the internal defect K of the plate glass 10 is measured under the same conditions by the same laser measuring apparatus as in Example, the value of T is 0.3 micrometer.

Example 2

Next, the sorting method and manufacturing method of the above-mentioned plate glass 1 are demonstrated. First, in a glass melting furnace composed of a refractory structure, predetermined glass raw materials previously uniformly combined so as to have the same composition as that of the glass material of Example 1 are vitrified by heating to a high temperature state, and homogeneous parts in the molten glass are known and homogenized. Use a device to make it homogeneous. Subsequently, this molten glass is introduced into a step of forming continuously by the overflow downdraw method, which is a kind of stretch molding method, and after the molten glass is overflowed from the fire resistant trough structure, it is downwardly formed by a molding apparatus equipped with a heat resistant roller. Stretch molding is performed. Thereafter, the molded parent glass is sorted with good or bad products by the following sorting method. First, in the inspection process by an expert inspector, mapping of the internal defect location in the parent glass is performed by using a foreign person's sensitive inspection, a foreign material measurement of an enlarged image by irradiation of the visible light onto the plate glass, and laser measurement. The values of the internal defect position and the internal defect dimension are input to the information terminal apparatus of the process control program connected to the LAN. The mapping point is to specify the foreign material position by inputting the foreign material type and foreign material size in the monitor previously divided by the grid shape of the checkerboard. This value is used to determine what kind of cutting is to be performed in the next machining step.

The measurement results obtained when the test was carried out were as follows. All internal defects show the characteristics as bubbles, and the measured value is the maximum bubble diameter in the range of 120 micrometers to 300 micrometers with respect to 15 sheets of glass 1 (1500 mm x 1800 mm, 0.7 mm thickness). The number was two in small and five in many. In addition, in any of the internal defects, the laser measurement is performed in the same manner as in Example 1 to evaluate the surface properties of the light-transmitting surface 2 of the most recent plate glass 1 at the location where this bubble exists. In the case where the bubble position of the light emitting surface 2, that is, the internal defect position is vertically projected on the light emitting surface by means of the device, the unevenness of the surface is measured for the light emitting surface position at the shortest distance. It did not affect the unevenness of the surface, and the unevenness of the surface of the translucent surface 2 was 0.01 micrometer-0.03 micrometer. Moreover, 60% of the total number existed in the range from 0.05 micrometer to 1.8 micrometers in depth, ie, the distance to the internal defect location with respect to this light transmitting surface, and the remaining 40% existed in the position deeper than 1.8 micrometers. In this way, as for the internal defects of any of them, it has been found that the depth does not interfere with the flat glass for the flat panel display of the present invention.

The parent glass, which is the base material to which the marking data and corresponding process control number are assigned, is precisely cut by scribe-dividing and end face processing in the machining step based on the information of the marking data, and is 20 inches from one sheet of the parent glass. As the plate glass 1 for flat panel displays used as a-Si (amorphous silicon) -TFT-LCD of 15, the plate glass 1 of 15 surfaces was obtained. At this time, since the cutting based on the information of the marking data was performed, the internal defect function of the plate glass 1 is such that the internal defect points are uniformly dispersed in the plurality of plate glass 1, and as a result, one sheet glass 1 The internal defect function present at was unbiased.

In this way, cleaning is carried out to remove foreign matters and the like in the final step, and the plurality of panes 1 are stored in a packing box which can be kept in an integrated stacked state in one rack, and are conveyed to a panel assembly maker to be transported to a 20-inch liquid crystal. It was assembled as a panel. As a result of evaluating the liquid crystal display panel manufactured by such a series of processes by the panel assembly maker, it turned out that it became the product which can be used without inferiority with the conventional panel.

Example 3

In addition, performing the cutting of the sheet glass by a similar method as in Example 2 with respect to the glass material having SiO ₂ 95% by mass or less, Al ₂ O ₃ at least 5% by mass of a composition which can be used as a device front glass plate of illustration field emission display And evaluation was performed. Next, the sorting method, the manufacturing method, and the result are shown.

In terms of mass% of oxide, SiO ₂ 50-65%, Al ₂ O ₃ 2-15%, MgO 0-4%, CaO 0-2.9%, SrO 2-13%, BaO 2-13%, MgO + CaO + SrO + BaO 17-27%, Li ₂ O 0-1%, Na ₂ O 2-10%, K ₂ O 2-13%, Li ₂ O + Na ₂ O + K ₂ O 7-15%, ZrO of _21-9%, so that a composition corresponding to TiO ₂ 0~5%, in the glass melting tank comprises a certain glass raw materials in advance uniformly combined with a refractory structure, and vitrified by heating at high temperatures, and the molten glass A heterogeneous site | part is made homogeneous using a well-known homogenizing apparatus.

Next, this molten glass is continuously introduced into a step of forming by a float method using a facility having a heating furnace equipped with a tin bath, and stretched molding is performed by a heat resistant roller. Subsequently, the molded lyophilized glass adopts a screening method by a skilled inspector, a laser measurement, or the like, and performs the inspection as described above in the inspection step to determine the good and bad parts of the plate glass, and to determine the internal defect points in the lyophilic glass. The mapping is performed and stored in the information terminal as predetermined data. This value is used to determine which cutting to perform in the next machining step.

The measurement result obtained in such an inspection process was as follows. First of all, the presence of foam defects as internal defect types was confirmed. In addition, although the test was carried out to collect six sheets of field emission display plates from the parent glass, the internal defects present in one sheet of glass have a maximum bubble diameter ranging from 300 µm to 500 µm. The number was one in the small and fifteen in the many. In addition, with respect to any of the internal defects, the surface properties of the light-transmitting surface 2 of the most recent plate glass 1 were evaluated by the same method as in the first and second embodiments with respect to the location where the bubbles exist. For this reason, as a result of measuring the unevenness of the surface of the light projecting surface 2 by a laser measuring device, the unevenness of the surface is not affected in any way, and the unevenness of the surface of the light projecting surface 2 is 0.01 μm to It was 0.04 micrometers. Moreover, 30% of the total number existed in the range from 0.03 micrometers to 2.1 micrometers in depth, ie, distance with respect to the light transmission surface to this internal defect location, and the remaining 70% existed in the position deeper than 2.1 micrometers. In this way, for both internal defects, the depth proved to be satisfactory as the flat glass for flat panel displays of the present invention.

Subsequently, the sheet glass corresponding to the marking data is precisely cut by a known predetermined processing method based on the information of the marking data in the processing step, and the sheet glass for six field emission displays as described above from one sheet of the glass sheet ( 1) was obtained. In addition, cutting based on the information of the marking data was performed, and the internal defect number of the plate glass 1 was such that the internal defect points were almost evenly dispersed in the plurality of plate glass 1.

In this way, cleaning is carried out to remove foreign matters and the like in the final step, and the plurality of panes 1 are stored in a packing box which can be kept in an integrated lamination state in one rack, and are conveyed to a panel assembly maker to display field emission displays. It was assembled as a panel. As a result of evaluating the field emission display panel manufactured by such a series of processes by the panel assembly maker, it turned out that it was the product which can be used comparably with the conventional panel.

As described above, the technology related to the flat glass for flat panel display of the present invention has a very wide application range, and in addition to the flat panel display application, the manufacturing method of the cover glass for the solid-state image sensor constituting the image input device and the EL display window Application to processing technology is also possible. Moreover, the manufacturing method of this invention can be employ | adopted not only for an image display use but also for processing techniques, such as plate glass for heat resistant glass plates and radiation shielding uses.

Claims (18)

As a method of inspecting internal defects of a plate glass having a light-transmitting surface and sorting good and defective products, Plate glass having a maximum dimension of the internal defects of 30 µm or more and a maximum depth or maximum height of the partial surface of the light-transmitting surface corresponding to the position of the internal defects exceeding 0.1 µm is regarded as a defective product. The sorting method of the plate glass for flat panel displays characterized by sorting the plate glass as a good product. As a method of inspecting internal defects of a plate glass having a light-transmitting surface and sorting good and defective products, The maximum dimension of the said internal defect is 30 micrometers or more, and the plate glass whose distance from the light-transmitting part partial area | region corresponding to the position of the said internal defect to the said internal defect is less than 0.01 micrometer is made into defective goods, and other plate glass is good. The sorting method of the plate glass for flat panel display panels characterized by the above-mentioned. A flat glass panel having a light-transmissive surface and having internal defects, And the maximum dimension of the internal defect is 30 µm or more, and the maximum depth or the maximum height of the partial surface of the light transmission surface corresponding to the position of the internal defect is 0.1 µm or less. A flat glass panel having a light-transmissive surface and having internal defects, The maximum dimension of the said internal defect is 30 micrometers or more, and the distance from the light-transmitting part partial area | region corresponding to the position of the said internal defect to the said internal defect is 0.01 micrometer or more, The glass plate for flat panel display panels characterized by the above-mentioned. The flat panel display plate glass according to claim 3 or 4, wherein the plate glass has the light transmitting surfaces on both surfaces thereof, and the light transmitting surface has an area of 20 × 10 ⁵ mm 2 or more in total on both surfaces. The plate glass for flat panel displays according to claim 3 or 4, wherein the plate glass is plate glass produced by dividing two or more sheets from the parent glass. The flat glass for flat panel displays of Claim 3 or 4 used for a liquid crystal display device. The plate glass for flat panel displays according to claim 3 or 4, which is used for a TFT liquid crystal display device. The flat glass for flat panel displays of Claim 3 or 4 used for an inorganic or organic electroluminescent display. The flat glass for flat panel displays of Claim 3 or 4 used for a field emission display. The flat glass according to claim 3 or 4, wherein the plate glass has a linear internal transmittance of 90% or more with respect to visible light having a wavelength of 450 nm to 650 nm in a portion including the internal defect. . The plate glass for a flat panel display according to claim 3 or 4, wherein the plate glass is silicate glass containing 95% by mass or less of SiO _{2 and} 5% by mass or more of Al ₂ O ₃ . The plate glass for flat panel displays according to claim 3 or 4, wherein the plate glass is an alkali free glass. The flat panel display panel glass according to claim 6, wherein the flat glass is produced by an extension molding method. A molding process of forming molten glass into a plate shape by an extension molding method to obtain a fluorophilic glass having a light transmitting surface, an inspection process for inspecting internal defects of the lipophilic glass, and cutting the erogenous glass inspecting the internal defects 2 Including the cutting process of obtaining the above plate glass, In the inspection step, a defective portion having a maximum dimension of the internal defect of 30 mu m or more and having a maximum depth or a maximum height of the partial transmissive surface corresponding to the position of the internal defect exceeding 0.1 mu m is detected. If it is, the manufacturing method of the flat panel display plate glass, characterized in that for cutting the parent glass to remove the defective portion in the cutting process. The method for manufacturing a plate glass for flat panel display according to claim 15, wherein the stretch forming method is an overflow downdraw method. The said inspection process is performed by irradiating at least one of visible light, a laser beam, an electron beam, and an ultrasonic wave to the said laminated glass, The manufacturing method of the plate glass for flat panel displays characterized by the above-mentioned. The method for manufacturing a plate glass for a flat panel display according to claim 15, wherein the plate glass having a smaller size is obtained by repeating the cutting step one or more times with respect to the parent glass remaining through the cutting step.

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