JP5183811B2 - Manufacturing method of glass substrate for liquid crystal display device - Google Patents

Description

  The present invention relates to a method for manufacturing a glass substrate for a liquid crystal display device.

  A flat glass plate is used as a display part of a flat panel display such as a liquid crystal display device or a plasma display device. In the following description, such a glass plate is referred to as a glass substrate for a flat panel display or simply a glass substrate.

  For example, in a liquid crystal display device, a moving image can be displayed by changing the electric field applied to the liquid crystal sealed between the glass substrates and changing the orientation of the liquid crystal. Since it is necessary to change the electric field when displaying an image on the liquid crystal display device, a transparent electrode for applying a voltage is formed on the glass substrate.

  In addition, an active matrix using thin film transistors (TFTs) is used in liquid crystal display devices used in television receivers that require high-quality display in order to control the on / off of the voltage applied to the electrodes on the glass substrate. System control is adopted. This TFT is also formed on the glass substrate.

  As described above, electrodes and active elements are formed by a very thin metal film or semiconductor on the glass surface of a glass substrate for a flat panel display. Therefore, the glass surface of the glass substrate has extremely high flatness and extremely high cleanliness. Sex is required.

  By the way, if the glass substrate for flat panel displays is what is used for a liquid crystal display device (henceforth a liquid crystal glass substrate), it will exhibit a thin rectangular plate-like form. The glass substrate for liquid crystal is usually about 0.5 mm to 0.7 mm and thinner than 1 mm, and the demand for an increase in size is increasing year by year.

  The glass substrate for liquid crystal is supplied to the manufacturing process of the liquid crystal display device in a form called mother glass having a size corresponding to the size of a plurality of glass substrates having a size required for one liquid crystal display device. The size of the mother glass is conventionally expressed as a generation, and for example, the size of the sixth generation mother glass is 1500 mm × 1850 mm. The mother glass is obtained by cutting a glass plate formed into a plate shape into a predetermined size. And in order to remove the stain | pollution | contamination, chip, etc. which were produced at the time of the cutting | disconnection of a glass plate, washing | cleaning of the glass substrate for liquid crystals which is mother glass is needed.

  In the cleaning of the glass surface of the liquid crystal glass substrate performed in such a situation, various liquids such as pure water, detergents such as surfactants, and fluorine compounds are used. The liquid used for cleaning the glass surface is removed by a jet of air, and after the cleaning process is completed, it is shipped through an inspection process, but it is faintly called a watermark on the surface of the liquid crystal glass substrate. Traces may remain.

  When such a watermark is generated, a defect occurs in an electrode or an element formed on the glass substrate due to the watermark, causing a failure of the liquid crystal display device. In addition, cleaning is also performed when a member necessary for liquid crystal display is formed on a glass substrate for liquid crystal. However, in the cleaning performed in such a case, a problem of generation of a watermark occurs.

  Therefore, in order to prevent the generation of a watermark, for example, as described in Patent Document 1 (Japanese Patent Application Laid-Open No. 2009-6299), the liquid crystal after washing is conventionally washed by a thin flat jet air flow such as an air knife. A liquid such as a detergent used for cleaning is removed from the glass surface of the glass substrate.

  However, since the ejected airflow is formed by the air flow, even if the liquid such as the detergent used for cleaning is removed from the glass surface by the ejected airflow, the generation of the watermark cannot be completely prevented.

  The subject of this invention is providing the manufacturing method of the glass substrate for liquid crystal display devices which can reduce significantly the frequency which a watermark produces after removing liquids, such as detergent, by a jet flow, compared with the past.

  The method for manufacturing a glass substrate for a liquid crystal display device according to the present invention includes a molding step of forming molten glass into a glass substrate, a cleaning step of cleaning the surface of the glass substrate with a detergent, and the surface of the glass substrate cleaned in the cleaning step And a rinsing step with a liquid. The cleaning step includes a spraying step of spraying a detergent onto the surface of the glass substrate and a removing step of removing the detergent by supplying a jet stream extending to the surface of the glass substrate. In the removal step, the wind speed of the jet stream is adjusted uniformly in the extending direction.

  Since the detergent used in the cleaning process is uniformly removed from the surface of the glass substrate by the jet air flow having a uniform wind speed in the extending direction, generation of watermarks on the surface of the glass substrate is suppressed. Here, the uniform wind speed means that the wind speed is within a predetermined range because of the influence of an error of the wind speed measuring device, a measurement error, and the like.

  In the method for manufacturing a glass substrate for a liquid crystal display device according to the present invention, the glass substrate is preferably coated with a black matrix. A glass substrate coated with a black matrix is used as a color filter of a liquid crystal display device.

  In the removing step of the method for producing a glass substrate for a liquid crystal display device according to the present invention, the absolute value of the deviation of the wind speed of the jet stream is preferably 15% or less of the average value of the wind speed of the jet stream. For example, when the average value of the wind speed of the jet stream is 8.0 m / s, the wind speed of the jet stream is preferably in the range of 6.8 m / s to 9.2 m / s.

  In the method for manufacturing a glass substrate for a liquid crystal display device according to the present invention, it is preferable that the method further includes a drying step, an inspection step, and a jet air flow adjustment step. In the drying process, the glass substrate rinsed in the rinsing process is dried. In the inspection process, the quality of the glass substrate dried in the drying process is inspected. In the jet air flow adjustment process, the wind speed of the jet air flow in the removal process is adjusted according to the quality of the glass substrate inspected in the inspection process. In the removal step, when the detergent is not uniformly removed by the jet stream, the quality of the glass substrate is deteriorated by the watermark appearing on the surface of the glass substrate. In the inspection process, the quality of the glass substrate is determined, and in the jet air flow adjustment process, the wind speed of the jet air flow is adjusted based on the determination result so that the detergent is uniformly removed.

  In the method for manufacturing a glass substrate for a liquid crystal display device according to the present invention, in the inspection process, fine water droplets are sprayed on the surface of the glass substrate to measure the contact angle of the water droplets adhering to the surface of the glass substrate. It is preferable to inspect the quality of the glass substrate based on the above. Thereby, the watermark which generate | occur | produces on the surface of a glass substrate can be discriminate | determined in an inspection process. In addition, the unevenness of the contact angle of water droplets is similar in appearance to the unevenness that occurs when a black matrix is applied to the surface of the glass substrate, so by reducing the unevenness of the contact angle of water droplets, Unevenness generated when the black matrix is applied can be reduced.

  In the method for manufacturing a glass substrate for a liquid crystal display device according to the present invention, the liquid such as detergent is uniformly removed by the jet stream, so that the frequency of occurrence of the watermark after the removal can be greatly reduced compared to the conventional case. . Moreover, in the manufacturing method of the glass substrate for liquid crystal display devices which concerns on this invention, the nonuniformity which arises when apply | coating a black matrix on the surface of a glass substrate can be reduced.

The flowchart for demonstrating the outline | summary of the manufacturing method of a glass substrate. The schematic plan view for demonstrating the process of the washing | cleaning of the glass substrate which concerns on one Embodiment of this invention. Schematic for demonstrating the process of the washing | cleaning of the glass substrate which concerns on one Embodiment. The front view of the air ejection apparatus shown in FIG. (A) The partial enlarged plan view which shows the wind speed measurement state of an air ejection apparatus, (b) The partial expansion perspective view which shows the wind speed measurement state of an air ejection apparatus. (A) The conceptual diagram for demonstrating the airflow at the time of the conventional wind speed measurement, (b) The conceptual diagram for demonstrating the airflow at the time of the wind speed measurement of this invention. The table | surface regarding the relationship between the measured value of the wind speed of a jet flow, and generation | occurrence | production of the cloudiness nonuniformity in a steam test. The conceptual diagram showing the point which measures the contact angle of the water adhering to the surface of a glass substrate. The table | surface regarding the measurement result of Example 1 of the contact angle of the water adhering to the surface of a glass substrate. The table | surface regarding the measurement result of Example 2 of the contact angle of the water adhering to the surface of a glass substrate.

<Outline of glass substrate manufacturing process>
FIG. 1 shows an outline of the process from the melting of the raw material to the next process for processing the glass surface, from the melting of the raw material to the liquid crystal glass substrate in the state of mother glass. In the melting / molding step S1 of FIG. 1, first, various powders such as silica sand as raw materials are weighed and mixed and put into a melting furnace. This powder is melted in a high-temperature melting furnace to become a glass melt. Thereafter, the glass melt that has been homogenized by defoaming and stirring is formed into a plate shape. After the glass formed into a plate shape is cooled, it is cut into specified dimensions to form a base plate.

  In the cutting step S2, the base plate is further cut in order to obtain a size suitable for manufacturing the liquid crystal display device. The glass substrate cut out from the base plate matches the size of the mother glass. In the next chamfering step S3, the cut glass substrate is polished in order to smooth the cut end. In the next cleaning step S4, fine foreign matters and dirt on the glass surface of the glass substrate are removed by cleaning. Then, in the next inspection step S5, an inspection is performed for the presence of minute defects such as bubbles and scratches, and those that cannot be used in the liquid crystal display device are removed as defective products, and the non-defective products become mother glass. Details of the inspection step S5 will be described later. Then, for example, when processing the glass surface of the mother glass at another factory in a remote place, the mother glass is packed and transported in a transportable form.

  Cleaning of a glass substrate for a flat panel display appears in various scenes from the glass substrate manufacturing process to the completion of the flat panel display manufacturing process. In the glass substrate manufacturing process shown in FIG. 1, cleaning is performed in the cleaning process S4.

  In cleaning, various cleaning liquids are used in order to remove various stains adhering to the glass surface. In general, after cleaning with a cleaning liquid such as a neutral detergent as a cleaning liquid, a liquid that does not generate precipitates such as pure water is used as a rinsing liquid in the final stage to rinse the glass substrate.

  When cleaning a relatively large glass plate cut into a predetermined shape, such as a mother glass or a glass substrate for a flat panel display, while transporting the glass plate so that the glass plate is not damaged and the entire glass plate is cleaned. It is common to be exposed to a cleaning solution. Therefore, with regard to cleaning, basic handling is common to relatively large glass plates such as mother glass and glass substrates for flat panel displays. Therefore, in the following description, a glass plate cut into a predetermined shape such as a mother glass or a flat panel display glass substrate is referred to as a glass substrate, and a common cleaning method and structure of a cleaning apparatus will be described.

<Outline of glass substrate cleaning>
In general, in a mother glass cleaning process, which is one of the processes in which the glass surface of a glass substrate has to be most cleanly finished, the detergent and the rinsing liquid are removed from the glass surface by an air flow. Therefore, in the following description of the cleaning process of the glass substrate for flat panel display, the cleaning process before shipment of the mother glass will be described as an example. However, the present invention is not limited to the cleaning process before shipment of the mother glass, and various scenes are cleaned from the manufacturing process of the glass substrate for flat panel display to the completion of the manufacturing process of the flat panel display. The present invention is applicable to the process and is not limited to the following embodiment.

  In the above-described washing step S4, as shown in FIG. 2, after the detergent tank T1 is washed a plurality of times with the detergent, the pure water tank T2 is washed with the rinse liquid in order to wash away the detergent. Thereafter, the glass substrate 3 is dried in the drying tank T3.

  When the glass substrate 3 is cleaned, the glass substrate 3 passes through three tanks of the cleaning apparatus 100, that is, the detergent tank T1, the pure water tank T2, and the drying tank T3 while being transported by a plurality of transport rollers 5 arranged in parallel. It is common in the detergent tank T1 and the pure water tank T2 to perform the operation of wetting the glass substrate 3 with the liquid and removing the liquid with the jet airflow.

  Therefore, in order to simplify the description, FIG. 3 shows a process of cleaning the glass substrate 3 once in the detergent tank T1 and a drying process in the drying tank T3 among various processes for cleaning the glass substrate. Show. That is, FIG. 3 shows a cleaning process Pr1 of the detergent tank T1 for washing the glass substrate 3 with the detergent, a removal process Pr2 of the detergent tank T1 for removing the detergent on the glass substrate 3 with the jetted airflow, and a jetted airflow in the drying tank T3. Shows a drying process Pr3 for drying pure water remaining on the surface of the glass substrate 3, and other processes are omitted.

  Prior to the steps shown in FIGS. 2 and 3, there is an ejected airflow adjusting step for adjusting the ejected airflow. In the jet air flow adjustment step, the jet air flow used in the removing step of the detergent tank T1 and the pure water tank T2 and the drying step of the drying tank T3 is adjusted. The jet air flow adjustment step is a step including wind speed measurement and wind speed adjustment for adjusting the jet air flow having a uniform wind speed. After the adjustment for adjusting the jet airflow is performed once, the cleaning process, the removing process, and the drying process are repeatedly performed until the adjustment becomes necessary again. This jet air flow adjustment step will be described in detail later.

  Further, in addition to the jet air flow adjustment step, for example, the step of carrying in and carrying out the glass substrate 3 is omitted from FIG. 2 and FIG. It is appropriately combined with the jet air flow adjustment process, the cleaning process, the removal process, and the drying process.

  In the cleaning process Pr1 shown in FIG. 3, cleaning is performed, in the removal process Pr2, the detergent is removed, and in the drying process Pr3, pure water is dried. In each step, the glass substrate 3 is transported by a plurality of transport rollers 5. Each transport roller 5 rotates around the central axis in the same direction and at the same speed. Moreover, each conveyance roller 5 is arrange | positioned so that a center axis may be located in a line with the same horizontal, and has the same diameter. Therefore, the glass substrate 3 is smoothly and horizontally conveyed by the conveyance roller 5 at the same speed. The speed at which the glass substrate 3 is conveyed is a constant value selected from, for example, 3 m / min to 15 m / min.

  First, in the first cleaning process Pr1, a shower nozzle 4 for spraying detergent on the surface of the glass substrate 3 is arranged. The shower nozzle 4 is horizontally installed over a width wider than the width of the region through which the glass substrate 3 passes. The shower nozzle 4 sprays detergent in the width direction of the glass substrate.

  In the cleaning process Pr1, the surface of the glass substrate 3 is wet with a detergent solution. Further, the surface of the glass substrate 3 is removed by brushing the glass substrate 3 wet with a detergent solution with a cleaning brush (not shown).

  In the next removal step Pr2, the air ejection device 1 is used to remove the detergent placed on the surface of the glass substrate 3. The air ejection device 1 is horizontally installed over a width wider than the width of the region through which the glass substrate 3 passes. Moreover, the jet air flow formed by the air jet device 1 is linear along the longitudinal direction of the air jet device 1 and is jetted in a direction orthogonal to the traveling direction of the glass substrate 3 in plan view (FIG. 2). Further, the jetted airflow is jetted obliquely so that the angle formed with the traveling direction of the glass substrate 3 in the side view becomes an acute angle (see FIG. 3). That is, the air flow is adjusted so that air is jetted in the direction in which the glass substrate 3 is conveyed. The angle of the ejected airflow viewed from the side at this time will be described when the air ejecting apparatus 1 is described. Then, regardless of whether or not the glass substrate 3 being conveyed passes through the formation region of the jet airflow, the jet airflow is always ejected from the air jet device 1 at a constant wind speed.

  As the glass substrate 3 is transported by the transport roller 5, the glass substrate 3 moves relative to the ejected airflow. Thereby, the detergent on the glass substrate 3 is scraped off in order from the end of the glass substrate 3 by the jet airflow.

  Later, in order to prevent a watermark from being generated on the surface of the glass substrate, an important point in the cleaning process Pr2 is that the detergent on the surface of the glass substrate 3 is uniformly removed. The watermark is unevenness generated when the detergent components remaining on the surface of the glass substrate 3 remain unevenly on the surface of the glass substrate 3 after the drying step Pr3.

  In the next drying step Pr3, the air ejection device 2 is used to dry the glass substrate 3. In the step of removing the pure water tank T2, pure water is removed, but it is not completely removed at the molecular level. Therefore, a drying step Pr3 is provided immediately after the removal step of the pure water tank T2, and the pure water is completely dried and removed by the air ejection device 2.

  The air ejection device 2 is horizontally installed over a width wider than the width of the region through which the glass substrate 3 passes. Moreover, the jet air flow formed by the air jet device 2 is also linear along the longitudinal direction of the air jet device 2 and is arranged so as to be inclined with respect to the traveling direction of the glass substrate 3 in plan view ( (See FIG. 2). Furthermore, the jetted airflow is formed obliquely so that the angle formed with the traveling direction of the glass substrate 3 is an acute angle in a side view (see FIG. 3). That is, both the air ejection device 1 and the air ejection device 2 eject air in the direction in which the glass substrate 3 is conveyed.

  In the above description, the supply of the rinsing liquid (pure water) by the shower nozzle 4 in the pure water tank T2 and the removal of the rinsing liquid by the air ejection device 2 are the detergents by the shower nozzle 4 and the air ejection device 1 in the detergent tank T1. The explanation is omitted because it is the same as supply and removal.

<Explanation of air blowing device>
FIG. 4 is a front view of the air ejection device 1. In this embodiment, the air ejection device 2 for drying the rinse liquid shown in FIGS. 2 and 3 has basically the same structure as the air ejection device 1 for removing the detergent. However, the air ejection device 2 is installed in the cleaning device 100 at a position and an angle different from those of the air ejection device 1. Thus, since the difference between the air ejection devices 1 and 2 is only the way of installation, only the structure of the air ejection device 1 will be described with reference to FIG.

  As shown in FIG. 4, the air ejection device 1 mainly includes an air supply unit 6 and a nozzle assembly 10. The nozzle assembly 10 is made of a material that is not easily rusted and has high rigidity, such as metal such as stainless steel or plastic. The air supply unit 6 for supplying air to the nozzle assembly 10 mainly includes an air supply device (not shown) such as a compressor, a connector 7 for connecting to the air supply device, and the connector 7 to the nozzle assembly 10. Tubes 8a and 8b for guiding air are provided. The air pressurized to a high pressure by the air supply device is guided to the tube 8 b disposed along the nozzle assembly 10 through the tube 8 a connected to the connector 7. The tube 8b is connected to the cavity 10f at both ends thereof and at five locations that divide the tube 8b into approximately six equal parts. The cavity 10 f is a space formed inside the nozzle assembly 10 along the longitudinal direction of the nozzle assembly 10. The air supplied from the air supply unit 6 is supplied to the cavity 10f via the tubes 8a and 8b. The air supplied to the cavity 10 f flows along the longitudinal direction of the nozzle assembly 10 toward the slit 10 g provided at the tip of the nozzle assembly 10. The air that has passed through the slit 10 g is air that is ejected from the nozzle assembly 10.

  The air supplied from the air supply unit 6 is clean air from which dust or the like has been removed by a filter, and is dry air that is kept at room temperature and is not humidified. The air sent to the air supply unit 6 is pressurized to a constant value selected between 0.02 Mpa and 0.15 Mpa, for example, by an air supply device.

  As shown in FIG. 4, the nozzle assembly 10 is fixed to the bracket 20 with screws 21, and the bracket 20 is fixed to the air ejection device 1 with screws 22.

<Description of wind speed measuring device>
FIG. 5A is a plan view showing a state where the wind speed measuring device 40 is attached to the nozzle assembly 10, and FIG. 5B is a perspective view of the state of FIG. The wind speed measuring device 40 mainly includes a probe 43 having a wind speed sensor 45 that senses the wind speed, and an anemometer body (not shown) that processes an electric signal sent from the probe 43 and displays the wind speed. . The probe 43 has a cylindrical appearance with a diameter of about 10 mm and a length of about 150 mm. An opening 44 having a substantially rectangular shape in plan view is formed at the tip of the probe 43, and a wind speed sensor 45 made of heat rays is disposed near the center tip of the opening 44. By placing this wind speed sensor 45 in the ejected airflow to be measured, the wind speed of the ejected airflow is measured.

  The probe 43 includes a temperature sensor (not shown) for measuring the temperature of air simultaneously with the wind speed, and a temperature compensation sensor (not shown) for ensuring an error in wind speed measurement due to a change in air temperature. )).

  The measurement value of the wind speed is obtained by measuring the amount of heat taken from the wind speed sensor 45 (heat ray) by the wind speed with the probe 43 and performing calculation based on the relationship between the amount of heat and the wind speed in the anemometer body. The measurement result of the wind speed is displayed on the display device of the anemometer body.

  As such a wind speed measuring apparatus, for example, Anemo Master Anemometer MODEL 6115 manufactured by Nippon Kanomax Co., Ltd. can be used.

<Description of wind speed measuring jig>
Next, the wind speed measuring jig will be described. In the wind speed measuring jig 30 shown in FIGS. 5A and 5B, a rectangular parallelepiped metal is processed into a shape for fixing the probe 43 of the above-described wind speed measuring apparatus 40 to the air ejection apparatuses 1 and 2. It will be.

  The wind speed measuring jig 30 includes a left side wall 31 and a right side wall 32. Then, the left side wall 31 and the right side wall 32 are coupled by the front beam 33 and the rear beam 34. Therefore, an opening 30 a is formed from the upper part of the wind speed measuring jig 30 toward the lower part. The left side wall 31, the right side wall 32, the front beam 33, and the rear beam 34 have the same height, and the upper surface 30d is flush.

  Since the cylindrical probe 43 is inserted, the inner surfaces of the left side wall 31 and the right side wall 32 are scraped, and the lower portions of the front beam 33 and the rear beam 34 are scraped to form a fitting portion 30c. In order to stably fix the cylindrical probe 43 in the inserted state, screw holes with female threads are formed in the left side wall 31 and the right side wall 32 so as to communicate with the fitting portion 30c.

  When the wind speed measuring jig 30 is applied in the vicinity of the slit 10g of the nozzle assembly 10 of the air ejection devices 1 and 2, the state in which the wind speed measuring jig 30 is in contact with the nozzle assembly 10 can be stably maintained, and the extra A trapezoidal dent is formed in the edge portions 31a and 32a of the left side wall 31 and the right side wall 32 so that an air passage is not possible.

<Explanation of jet flow adjustment process>
In the jet air flow adjustment step, measurement of the wind speed of the jet air flow and adjustment of the interval between the slits 10g of the air jet devices 1 and 2 for correcting the wind speed based on the measurement value are repeated. When adjusting, the average value of the wind speed values of all the measurement points measured first is used as a reference. Then, the gap of the slit 10g is adjusted with a tool so as to approach the reference value. By such an operation, the interval between the slits 10g of the air ejection devices 1 and 2 is adjusted between 0.1 mm and 1 mm, and the wind speed of the ejection airflow is adjusted to a desired value.

  That is, when the measured value is smaller than the desired wind speed, the pipe resistance of the tubes 8a and 8b is reduced by increasing the width of the slit 10g to increase the wind speed. Conversely, when the measured value is larger than the desired wind speed, the pipe resistance of the tubes 8a and 8b is increased by narrowing the width of the slit 10g to reduce the wind speed.

  The interval between the slits 10g is not always uniform along the longitudinal direction of the nozzle assembly 10 (that is, the width direction of the glass substrate 3). This is because the pressure of the air supplied to the slit 10g is high at a point close to the connection part between the tube 8b and the cavity 10f and low at a point far from the connection part such as both ends of the cavity 10f. That is, even if the interval between the slits 10 g is uniform at each point in the longitudinal direction of the nozzle assembly 10, the wind speed of the jet air flow ejected from the slit 10 g is uniform at each point in the longitudinal direction of the nozzle assembly 10. Don't be. Therefore, in the present embodiment, the interval between the slits 10 g is finely adjusted along the longitudinal direction of the nozzle assembly 10 in order to make the air velocity of the jet airflow uniform. Specifically, as shown in FIG. 4, since the slit 10g extends long along the longitudinal direction of the nozzle assembly 10, the slit 10g is moved while moving the wind speed measuring device 40 along the longitudinal direction of the slit 10g. The interval adjustment is repeated.

  When measuring the wind speed, the wind speed sensor 45 of the wind speed measuring device 40 is disposed on the extension of the slit 10g of the nozzle assembly 10, as shown in FIG. At this time, the probe 43 is fixed to the wind speed measuring jig 30 with a screw 38. Since the probe 43 has a cylindrical shape, the probe 43 rotates with respect to the fitting portion 30c around the central axis. Therefore, when fixing with the screw 38, the opening 44 of the probe 43 is attached on the basis of the state facing the surface parallel to the upper surface 30d of the wind speed measuring jig 30. The nozzle assembly 10 and the probe 43 are accurately positioned by the wind speed measuring jig 30 so that the positional relationship between the wind speed sensor 45 and the slit 10g is accurately reproduced.

  As shown in FIG. 5B, the nozzle assembly 10 and the probe 43 can be accurately positioned as described above because the edge 31a of the left side wall 31 of the wind speed measuring jig 30 is a nozzle near the slit 10g. This is because the outer shape matches the outer shape of the assembly 10. Although not shown in the drawing, the edge portion 32a of the right side wall 32 has an outer shape that matches the outer shape of the nozzle assembly 10 in the vicinity of the slit 10g, similarly to the edge portion 31a of the left side wall 31.

  Measurement using such a wind speed measuring jig 30 improves the accuracy and accuracy of wind speed measurement as compared with the case where only the probe 43 is measured in the air flow of the jet airflow. The reason why the accuracy and accuracy of wind speed measurement is improved will be briefly described with reference to FIGS. 6 (a) and 6 (b). 6 (a) and 6 (b), the air flow is conceptually indicated by arrows. FIG. 6A shows a case where only the probe 43 is placed in the air flow. In this case, since the probe 43 disturbs the air, the measurement of the wind speed with high accuracy and accuracy is hindered by the influence of the air flowing through the regions 51 and 52 on both sides of the region 50 to be measured. Since the air flow of the squirting airflow is fast and the thickness of the laminar air flow is thin, the influence disturbed by the shape of the probe 43 increases. On the other hand, as shown in FIG. 6 (b), if the left side wall 31 and the right side wall 32 prevent the area 50 to be measured from being affected by the air flow in the areas 51 and 52 on both sides, The flow of air led to the inside is arranged, and the wind speed with high accuracy and accuracy can be measured.

<Watermark inspection>
A glass substrate 3 used as a mother glass of a liquid crystal display device is used for manufacturing a color filter, for example. In the color filter manufacturing process, first, a black matrix is applied on the glass substrate 3, and then a coloring material is applied on the black matrix film in a fine pattern to form colored pixels. The black matrix has a light shielding property, and prevents light leakage at the time of black display and color mixture between adjacent colored pixels. The colored pixels function as a filter that transmits red, green, and blue light.

  In the removal step Pr2, when the detergent on the surface of the glass substrate 3 is not uniformly removed, a watermark is generated on the surface of the glass substrate 3 after the drying step Pr3. The inventor of the present application finds that when a black matrix is applied to the glass substrate 3 on which a watermark is generated, black matrix unevenness (hereinafter referred to as “BM unevenness”) occurs on the surface of the glass substrate 3. It was. Since BM unevenness can be discerned visually, when a liquid crystal display device is manufactured using this glass substrate 3, the liquid crystal display device has a defect that appears in the appearance. Therefore, it is preferable to discriminate the glass substrate 3 on which the watermark is generated in order to select and remove the glass substrate 3 on which the BM unevenness is generated before applying the black matrix on the glass substrate 3 in advance.

  In the present embodiment, by performing a steam test in the inspection step S5, it is possible to efficiently determine the glass substrate 3 on which the watermark is generated. In the steam inspection, steam is sprayed on the surface of the glass substrate 3 to attach minute water droplets, and the entire surface of the glass substrate 3 is clouded. Then, it is inspected whether or not the degree of cloudiness on the surface of the glass substrate 3 is uneven. When steam is sprayed on the glass substrate 3 where the watermark is generated, cloudy unevenness due to non-uniform adhesion of water droplets to the surface of the glass substrate 3 appears.

  The steam inspection in the inspection step S5 is based on the fact that the contact angle of water with respect to the surface of the glass substrate 3 on which the watermark is generated differs depending on the point on the surface of the glass substrate 3 because the detergent is not uniformly removed. ing. That is, when the detergent on the surface of the glass substrate 3 is not uniformly removed, the area on the surface of the glass substrate 3 where the detergent is completely removed and the surface of the glass substrate 3 where the detergent remains slightly The contact angle of water with respect to the surface of the glass substrate 3 differs from the region. In the region where the contact angle of water is small, the height of the water droplets adhering to the surface of the glass substrate 3 is small, so that the water droplets are close to transparency visually. On the other hand, in the region where the contact angle with respect to water is large, the height of the water droplets adhering to the surface of the glass substrate 3 is large, so that the water droplets are cloudy (cloudy) visually. That is, when the detergent on the surface of the glass substrate 3 is not uniformly removed, the contact angle of water with respect to the surface of the glass substrate 3 varies depending on the points on the surface of the glass substrate 3. Cloudy unevenness occurs.

  Therefore, in the steam inspection in the inspection step S5, the cloudy unevenness generated on the surface of the glass substrate 3, that is, the watermark appearing on the surface of the glass substrate 3 by visually observing the surface of the glass substrate 3 sprayed with steam. Thus, the glass substrate 3 on which BM unevenness is generated can be selected in advance.

<Measurement data of the wind speed of the jet stream>
The relationship between the measured value of the air velocity of the jet air flow of the air jet device 1 that removes the detergent placed on the surface of the glass substrate 3 in the removal step Pr2 and the presence or absence of cloudy unevenness generated on the surface of the glass substrate 3 in the steam test. Is shown in FIG. In FIG. 7, the “deviation of the wind speed of the jet stream” is the difference between the wind speed of the jet stream at each of a plurality of points along the longitudinal direction of the slit 10g and the average value of the wind speed of the jet stream. It is an index to represent.

  FIG. 7 shows average values and deviations of the jet velocity of the jet airflow for each of “Example 1”, “Example 2”, and “Comparative Example”. As shown in FIG. 7, the deviation of the wind speed of the jet stream in “Comparative Example” is larger than the deviation of the wind speed of the jet stream in “Example 1” and “Example 2”. In the “comparative example” in which the deviation of the air velocity of the jet airflow is large, it is determined that a watermark is generated on the glass substrate 3 because the cloudy unevenness in the steam test has occurred. On the other hand, in “Example 1” and “Example 2”, as described above, since no cloudy unevenness in the steam test occurred, it is determined that no watermark is generated on the glass substrate 3.

<Contact angle measurement data>
As reference, measurement data of the contact angle of water with the surface of the glass substrate 3 will be described. The contact angle of water is measured at nine points located at substantially equal intervals along the width direction of the glass substrate 3, as shown in FIG. 8, after 24 hours have elapsed from the completion of the drying process in the drying tank T3. Performed in P1-P9. Specifically, a minute water droplet was attached to the surface of the glass substrate 3, and after 10 seconds had elapsed, measurement of the contact angle of water was started. The contact angle of water was measured 10 times in 4 seconds from the start of measurement. FIG. 9 and FIG. 10 show the measurement results of the contact angle of water with respect to the glass substrate 3 in “Example 1” and “Example 2” of FIG. 7 described above, respectively. The table of FIG. 9 and FIG. 10 shows the 10 measured values of the water contact angle at the points P1 to P9 and the average value of the 10 measured values, respectively. From FIG. 9, the ten times measurement average value of the water contact angle in “Example 1” showed the minimum value 28.6 at the point P7 and the maximum value 34.4 at the point P1. From FIG. 10, the 10 times measurement average value of the water contact angle in “Example 2” showed the minimum value 25.2 at the point P7 and the maximum value 33.1 at the point P2.

  From the measurement data of the air velocity of the jet air flow and the contact angle of water described above, the air velocity of the jet air flow of the air jet device 1 is preferably as uniform as possible along the slit 10g. The absolute value of is more preferably 15% or less of the average value of the wind speed of the jet stream. For example, when the wind speed of the jet stream is 8.0 m / s, the range of the wind speed variation of the jet stream is 8.0 m / s ± 1.2 m / s (that is, 6.8 m / s to 9.2 m / s). ) Is preferable.

  In the present embodiment, when it is determined that the detergent on the surface of the glass substrate 3 has not been uniformly removed in the steam inspection in the inspection step S5, in the jet air flow adjustment step, the jet air flow of the air jet device 1 is determined. The wind speed is adjusted to be uniform. For example, the interval of the slits 10g is adjusted so that the absolute value of the deviation of the wind speed of the jet stream is 15% or less of the average value of the wind speed of the jet stream. By adjusting the wind speed of the jet airflow of the air jetting device 1, the detergent is uniformly removed from the surface of the glass substrate 3, and as a result, occurrence of cloudy unevenness appearing on the surface of the glass substrate 3 in the steam test is reduced. The That is, the detergent can be uniformly removed from the surface of the glass substrate 3 by adjusting the wind speed of the jet airflow of the air jetting device 1 so that the cloudiness unevenness generated in the steam test is reduced.

<Features>
(A) In the cleaning process Pr1, the detergent is uniformly removed from the surface of the glass substrate 3 because the detergent is removed from the surface of the glass substrate 3 by the air (ejection airflow) ejected from the air ejection device 1 at a uniform wind speed. Is done. Therefore, unevenness in removing the detergent is unlikely to occur, and the generation of watermarks appearing on the surface of the glass substrate 3 can be greatly reduced.

  In order to remove the detergent uniformly, it is necessary to make the wind pressure of the jet stream constant, but since the wind pressure is proportional to the square of the wind speed, there is no unevenness of the detergent by making the wind speed constant. It can be removed.

  In addition, although the said embodiment demonstrated the removal of a detergent, the liquid removed with a jet stream may be another washing | cleaning liquid and peeling liquid. Further, in the cleaning process Pr1, the detergent is sprayed on the surface of the glass substrate 3 by the shower nozzle 4, but the surface of the glass substrate 3 may be wetted by other equipment.

  Since the interval of the slits 10g is adjusted so that the wind speed of the air injected from the measurement region 50 of the slit 10g of the air ejection device 1 is uniform, the interval of the slits is not necessarily uniform, but the air velocity of the air is 10g. It becomes the same in any part of. By using a jet air flow having a uniform wind speed, the generation of watermarks can be extremely effectively reduced.

  Moreover, the detergent removed from the glass substrate 3 by the air ejection device 1 can be reused, and the loss of the detergent can be reduced.

  (B) In the removal step Pr2, the surface of the glass substrate 3 is uniformly wetted with the detergent in the width direction of the glass substrate 3 until the detergent is removed by the jet stream. If the surface of the glass substrate 3 is not uniformly wetted with the detergent, there will be a difference in how the jet airflow hits where it is wetted and where it is not wetted. And the difference in how the blown airflow hits may cause a disorder in how the detergent is removed. By uniformly wetting the glass surface with the detergent, the above-mentioned problems are avoided and the detergent is removed without unevenness, the occurrence of watermarks is further reduced, and the effect of reducing the occurrence of watermarks is increased.

  (C) When the wind speed measuring jig 30 has the left side wall 31 and the right side wall 32 (partition member) and measures the wind speed of the air jetted from the slit 10g, from the left and right areas 51, 52 of the measurement area 50 It is configured not to be affected by the air that is jetted. Therefore, it is possible to avoid that the measurement value of the wind speed in the measurement area 50 is changed by the influence of the areas 51 and 52 on both the left and right sides. Thus, it is easy to uniformly adjust the wind speed ejected from the slit.

  Moreover, the left side wall 31 and the right side wall 32 have the edge parts 31a and 32a which correspond to the shape of the slit periphery of an air ejection apparatus. As a result, the edges 31a and 32a of the left side wall 31 and the right side wall 32 match the shape around the slit 10g of the air ejection device 1, so that a gap is created between the edges 31a and 32a and the shape around the slit 10g. Air disturbance can be prevented from occurring. Therefore, since it is possible to create a situation that is not affected by the air jetted from the areas 51 and 52 on the left and right sides of the measurement area 50, the wind speed of the ejected airflow can be measured with high accuracy at a large number of measurement points, and the uniform wind speed It becomes easy to form a jet air flow.

  At the time of wind speed measurement, the wind speed measurement jig 30 is simply applied to the nozzle assembly 10 of the air ejection device 1, so that the wind speed can be measured quickly and the time required for the ejection airflow adjustment process can be shortened. Further, by using the wind speed measuring jig 30, it is possible to reduce measurement errors caused by the measurer, to increase the accuracy of air wind speed adjustment, and to easily suppress the generation of watermarks.

  The front beam 33 and the rear beam 34 join the left side wall 31 and the right side wall 32 with a predetermined length therebetween. The left side wall 31, the right side wall 32, the front beam 33, and the rear beam 34 have a fitting portion 30c into which the probe 43 of the wind speed measuring device 40 is fitted. And the left side wall 31 and the right side wall 32 are arrange | positioned so that it may contact | abut on the side surface of the probe 43 without a gap in the state by which the probe 43 was fitted by the fitting part 30c. Therefore, since there is no gap between the probe 43 and the left side wall 31 and the right side wall 32, it is possible to eliminate the influence of air disturbance on the side surface of the probe 43 and perform comparative measurement of wind speed with high accuracy. Therefore, it is easy to form a jet stream with a uniform wind speed.

  The front beam 33, the rear beam 34, the left side wall 31, and the right side wall 32 are disposed so as to surround the four sides of the measurement opening 44 at the same height. Since the front beam 33 and the rear beam 34 having the same height as the left side wall 31 and the right side wall 32 can prevent air from entering the measurement region from the front and rear, and can reduce the error in comparative measurement of wind speed. Formation of a jet stream with uniform wind speed is facilitated.

  (D) In the spout air flow adjustment step, the variation in the air speed of the spout air flow is suppressed and the air speed of the spout air flow is made uniform so as to reduce the cloudiness unevenness appearing on the surface of the glass substrate 3 in the steam inspection in the inspection step S5. Therefore, the interval between the slits 10g of the air ejection device 1 is adjusted. Thereby, since the watermark appearing on the surface of the glass substrate 3 is reduced, BM unevenness appearing on the surface of the glass substrate 3 is also reduced. Therefore, since the production amount of the glass substrate 3 in which BM unevenness occurs is reduced, the reliability of the glass substrate 3 used as the mother glass of the liquid crystal display device can be improved.

<Modification>
(1) In the above embodiment, only one air ejection device 1 is used to remove the detergent or rinse liquid on the surface of the glass substrate 3, but two or more air ejection devices 1 may be used in parallel. Good.

  (2) In the above embodiment, the measurement error due to the air flowing in the areas 51 and 52 other than the area 50 to be measured is removed using the wind speed measuring jig 30, but the measurement error is reduced by other methods. It may be.

  (3) Although the case where the wind speed is measured by the specific wind speed measuring device 40 has been described in the above embodiment, the measurement of the wind speed is not limited to the method described in the above embodiment.

  (4) In the above embodiment, the air ejection device 1 and the air ejection device 2 both eject air toward the direction in which the glass substrate 3 is conveyed. Either or both may inject air in a direction opposite to the direction in which the glass substrate 3 is conveyed.

DESCRIPTION OF SYMBOLS 1, 2 Jet flow formation apparatus 3 Glass substrate 4 Shower nozzle 5 Conveyance roller 6 Air supply part 10 Nozzle assembly 30 Wind speed measuring jig 40 Wind speed measuring apparatus 43 Probe

JP 2009-6299 A

Claims (4)

A molding step of molding molten glass into a glass substrate;
A cleaning step of cleaning the surface of the glass substrate with a detergent;
A method for producing a glass substrate for a liquid crystal display device, comprising a step of rinsing the surface of the glass substrate washed in the washing step with a liquid,
The washing step includes
Spraying a detergent onto the surface of the glass substrate;
Removing the detergent by supplying a jetted air flow extending to the surface of the glass substrate,
In the removing step, the wind speed of the jet stream is uniformly adjusted in the extending direction , and the absolute value of the deviation of the wind speed of the jet stream is 15% or less of the average value of the wind speed of the jet stream. A method for producing a glass substrate for a liquid crystal display device. The method for manufacturing a glass substrate for a liquid crystal display device according to claim 1, wherein the glass substrate is coated with a black matrix. A drying step of drying the glass substrate rinsed in the rinsing step;
An inspection process for inspecting the quality of the glass substrate dried in the drying process;
And a jet air flow adjusting step of adjusting a wind speed of the jet air flow in the removing step according to the quality of the glass substrate inspected in the inspection step.
The manufacturing method of the glass substrate for liquid crystal display devices of Claim 1 or 2 . In the inspection step, water droplets are sprayed on the surface of the glass substrate, the contact angle of the water droplets adhered to the surface of the glass substrate is measured, and the quality of the glass substrate is inspected based on the unevenness of the contact angle.
The manufacturing method of the glass substrate for liquid crystal display devices of Claim 3 .

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