JP2010120797A - Glass substrate, flat panel display using the same and producing method of glass substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a glass substrate where the variation of the thickness of a coated film is suppressed to the utmost even when a coating material is coated on a surface by a coater at a state that a rear surface is adsorbed on a surface plate with no space. <P>SOLUTION: In a vertical cross section S being in parallel with one side 1b at all positions along to another side 1a which is one of orthogonal two sides when the glass substrate 1 being used for a flat panel display, having a rectangular shape whose one side has a size of 300 mm or more and having a mean plate thickness of 0.3-4.0 mm is adsorbed on the surface plate 2 with no space, it is constituted so that a relation denoted as ¾D(X)-T(X)¾≤7.5 μm is satisfied when the length of a perpendicular dropped from an upper contour line L1 to the surface plate 2 is exhibited by a function T(X) showing a relation with a position X in a direction along one side 1b and the length of a perpendicular dropped from a virtual straight line L2 connecting both ends A, B of the upper contour line L1 to the surface plate 2 is exhibited by a function D(X) showing a relation with the position X. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

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

  As is well known, flat panel displays such as plasma displays (PDP), field emission displays (including FED (including surface emission display (SED))), liquid crystal displays (LCD), and electroluminescence displays (ELD) are fine on the surface. Two glass substrates on which elements or structures such as transparent electrodes and partition walls are formed are made to face each other.

  This type of glass substrate is formed by drawing a molten glass by a drawing method such as an overflow down-draw method (fusion method) or a slot-down draw method, or a known method typified by a float method, and then drawing the plate. It is obtained by cutting the large glass base plate obtained by the above so that the four sides are rectangular with a predetermined dimension.

  Then, after a predetermined coating film is formed on the surface of the glass substrate cut into a rectangular shape by applying a coating material according to the type of the flat panel display by a coating device called a coater, The above-described elements and structures are formed by exposing and developing the coating film by, for example, a photoresist method.

  Therefore, if the thickness of the coating film formed on the glass substrate by the coater is uneven, exposure unevenness occurs when exposure is performed, and it becomes impossible to form elements and structures with high accuracy, insulation failure, light emission failure, Or there is a risk of causing a fatal defect for a flat panel display such as image quality degradation.

  Such a defect in the thickness of the coating film is mainly caused by the inappropriate thickness characteristics of the glass substrate. The reason is that if the thickness characteristics of the glass substrate are inadequate, the distance from the coater to the surface of the glass substrate will partially change, making it difficult to apply the coating material to the glass substrate with a constant thickness by the coater. It is because it becomes.

Therefore, for example, in Patent Document 1, attention is paid to such a characteristic of the thickness of the glass substrate, and the above-described problem that the thickness of the coating film is not uniform is attempted to be addressed. That is, in the same document, the maximum plate thickness and the minimum plate thickness of a glass substrate having a short side dimension of 300 to 3000 mm, a long side dimension of 300 to 3000 mm, and an average plate thickness of 1.5 to 3.0 mm. It is disclosed that the plate thickness difference is 20 μm or less, and that the plate thickness difference in a plate thickness measurement range over a unit of length 100 mm is 10 μm or less.
JP 2004-87382 A

  By the way, when applying a coating material on the surface of a glass substrate with a coater, in order to realize more accurate application, the back surface of the glass substrate is adsorbed and held on the surface plate without any gap, and the glass substrate is fixed on the surface plate. There is a case. In this case, since the back surface of the glass substrate is in close contact with the surface plate, the surface of the glass substrate is affected by the unevenness generated on the back surface of the glass substrate before the back surface of the glass substrate is adsorbed to the surface plate. That is, when there is a convex portion that protrudes upward on the surface of the glass substrate, and there is a convex portion that protrudes downward also on the back surface of the glass substrate at the same position, when the back surface of the glass substrate is adsorbed to the surface plate, The convex part on the back surface of the glass substrate is pushed upward, and the convex part on the surface of the glass substrate becomes larger. Therefore, before and after adsorbing the glass substrate to the surface plate, and after adsorbing, the state of irregularities appearing on the surface side of the glass substrate changes greatly, and as in the example described above, the glass substrate after adsorption is more The amplitude of the irregularities appearing on the surface also tends to increase. Therefore, it is necessary to manage the thickness characteristics of the glass substrate while the back surface of the glass substrate is adsorbed and held on the surface plate without any gap.

  In addition, when applying a coating material on the surface of the glass substrate by a coater, it is customary to adjust the orientation of the coater based on the height of the surface of the glass substrate in order to make the thickness of the coating film constant, It is necessary to manage the thickness characteristics of the glass substrate in consideration of adjusting the posture of the coater.

  The manufacturing process of the glass substrate may include a plurality of coating processes. In this case, a coating film or pattern is already formed in the region on the center side of the glass substrate surface in the previous process. It may not be possible to measure the exact height of the surface. Therefore, it is practically preferable to adjust the posture of the coater with reference to the heights of the surfaces of both ends of the glass substrate in the direction orthogonal to the moving direction of the coater. This is because accurate measurement of the height is possible without forming a coating film or the like at both ends of the glass substrate. However, the thickness characteristics of the glass substrate disclosed in Patent Document 1 are not stipulated on the premise that the orientation of the coater is adjusted based on the heights of the surfaces of both ends of the glass substrate. Therefore, even when the thickness characteristics disclosed in the same document are satisfied, the distance between the glass substrate and the coater becomes non-uniform when the posture of the coater is adjusted as described above, and a coating film cannot be formed uniformly. Can occur.

  In view of the above circumstances, the present invention provides a glass substrate capable of suppressing variations in the thickness of the coating film as much as possible even when the coating material is applied to the surface by a coater with the back surface adsorbed to the surface plate without any gaps. Doing this is a technical issue.

  The glass substrate according to the present invention, which was created to solve the above-mentioned problems, is used for a flat panel display, has a rectangular shape with a side dimension of 300 mm or more, and an average plate thickness of 0.3 to 4.0 mm. In a longitudinal section parallel to the other side at any position along either one of two orthogonal sides when the back surface is adsorbed onto the surface plate without any gap, from the upper contour line The length of the perpendicular line drawn down on the surface plate is represented by a function T (X) that is expressed in relation to the position X in the direction along the other side, and from the virtual straight line that connects both ends of the upper contour line, When the length of the perpendicular line drawn on the surface plate is expressed by the function D (X) shown in relation to the position X, the relationship | D (X) −T (X) | ≦ 7.5 μm is established. It is characterized by. Note that T (X) and D (X) mean the length of the vertical line dropped from the upper contour line at the position X to the surface plate and the length of the vertical line dropped from the virtual straight line to the surface plate, respectively. In addition, the lengths of the vertical lines dropped from the upper contour line to the surface plate and the vertical lines lowered from the virtual straight line to the surface plate are expressed by functions T (X) and D (X) on the other hand. This is because the length of each perpendicular changes depending on the position in the direction along the side.

  According to such a configuration, the thickness characteristic of the glass substrate in a state where the back surface is adsorbed onto the surface plate without a gap, the other at any position along one of the two orthogonal sides of the glass substrate. Is defined with reference to a virtual straight line connecting both ends of the upper contour line in a vertical cross section parallel to the side of the line. Since this imaginary straight line is a straight line connecting both ends of the upper contour line, regardless of whether the imaginary straight line is inclined with respect to the horizontal line, the orientation of the coater should be adjusted to be parallel to the virtual straight line. I can. And when the gap between this virtual straight line and the upper contour line representing the actual surface state of the glass substrate is very small, the upper contour line and the virtual straight line substantially coincide, the coater and the glass substrate surface The distance between can be made almost constant. Therefore, by appropriately managing the distance between the upper contour line and the virtual straight line, it is possible to suppress variations in thickness generated in the coating film formed by the coater. From such a viewpoint, as a result of intensive research, the present inventor has a relationship of | D (X) −T (X) | ≦ 7.5 μm between the virtual straight line and the upper contour line. It was found that variation in the thickness of the coating film formed by the coater can be suppressed as much as possible. In other words, it is possible to suppress the variation in the thickness of the coating film as much as possible only after satisfying the above numerical range, and it is not possible to enjoy such operational effects if it deviates from the numerical range.

  Said structure WHEREIN: It is manufactured by carrying out sheet drawing shaping | molding of a molten glass, It is preferable that the sheet drawing direction becomes parallel to said other side.

  In other words, even if the molten glass is drawn using any of the down draw methods such as the overflow down draw method (fusion method) or the slot down draw method, or the float method, the produced glass substrate plate The thickness variation tends to be small in the drawing direction and large in the direction perpendicular to the drawing direction. Therefore, also from the viewpoint of utilizing the tendency of the plate thickness characteristics of the glass substrate derived from the plate drawing, the drawing direction of the glass substrate is parallel to the other side, that is, in the longitudinal section parallel to the drawing direction, It is preferable to satisfy the relationship of | D (X) −T (X) | ≦ 7.5 μm.

  The above glass substrates can be used for PDPs, FEDs, and LCDs to maximize their effects. If a flat panel display is manufactured using these glass substrates, a display with excellent quality can be obtained. Can be obtained.

  In addition, the method according to the present invention, which was created in order to solve the above problems, is used for a flat panel display, has a rectangular shape with a side dimension of 300 mm or more, and an average plate thickness of 0.3 to 4.0 mm. After the molding process of molding the glass substrate, an application process of forming a coating film on the surface of the glass substrate while moving the coater that applies the coating material while the back surface of the glass substrate is adsorbed on a surface plate A method of manufacturing a glass substrate having a back surface adsorbed on the surface plate without a gap from the glass substrate molded in the molding step between the molding step and the coating step. In a longitudinal section parallel to the other side at any position along one of the two orthogonal sides, the length along the other side is the length of the perpendicular drawn from the upper contour line to the surface plate Position of A function D (X) that is represented by a function T (X) that is expressed in relation to the position and that indicates the length of a perpendicular line drawn from the virtual straight line connecting both ends of the upper contour line to the surface plate in relation to the position X ), A selection step of selecting a glass substrate that satisfies the relationship | D (X) −T (X) | ≦ 7.5 μm, and for the glass substrate selected in the selection step It is characterized in that the coating process is executed only.

  According to such a method, in the selection step, a glass substrate that satisfies the relationship | D (X) −T (X) | ≦ 7.5 μm is selected from the glass substrates formed in the forming step. . And if it is a glass substrate selected in this way, as already stated in paragraph 0013, the variation in the thickness of the coating film formed by the coater can be suppressed as much as possible. Therefore, if the coating process is performed only on the selected glass substrate, that is, the glass substrate satisfying the relationship of | D (X) −T (X) | ≦ 7.5 μm, the thickness of the coating film is not satisfied. It is not necessary to perform the coating process on a glass substrate having a poor plate thickness characteristic that causes an appropriate variation. Therefore, it is possible to reliably reduce the economical and time waste required for the coating process performed on a defective glass substrate.

  In the above method, when the coating material is applied by the coater in the coating step, the posture of the coater is controlled so that the distance between the coater and both ends of the upper contour line is constant. However, it is preferable to move the coater in a direction along the one side of the glass substrate.

  In this way, since the virtual straight line is a straight line connecting the both ends of the upper contour line, the coater can be controlled by simply controlling the distance between the coater and both ends of the upper contour line to be constant. And can be parallel. Therefore, it is possible to keep the coater's posture properly when applying the coating material to the glass substrate with simple control.

  As described above, according to the present invention, even when the coating material is applied to the surface by the coater with the back surface adsorbed to the surface plate without any gap, the glass substrate capable of suppressing the variation in the thickness of the coating film as much as possible. Can be provided.

  Hereinafter, the glass substrate according to the present invention will be described.

  FIG. 1 is a perspective view schematically showing a state in which a glass substrate for a flat panel display according to an embodiment of the present invention is adsorbed on a surface plate. The glass substrate 1 has a rectangular shape with a side of 300 mm or more, an average plate thickness of 0.3 to 4.0 mm, and is held by suction on a surface plate 2 having a plurality of suction holes (not shown). . The back surface of the glass substrate 1 held by suction is in close contact with the surface plate 2 without any gap, and the irregularities on the back surface of the glass substrate 1 are corrected by the surface plate 2. On the other hand, on the surface of the glass substrate 1, irregularities obtained by adding the irregularities generated on the back surface side appear.

And in the state which adsorb | sucked the back surface to the surface plate 2 in this way, the glass substrate 1 which concerns on this embodiment is a longitudinal cross section parallel to the other edge | side 1b in every position along one edge | side 1a of two orthogonal sides. S has the following characteristics. That is, as shown in FIG. 2, in the longitudinal section S, a function T indicating the length of the perpendicular line drawn from the upper contour line L1 to the surface plate 2 in relation to the position X in the direction along the other side 1b. (X) and the function D (X) showing the length of the perpendicular line drawn from the virtual straight line L2 connecting the both ends A and B of the upper contour line L1 to the surface plate 2 in relation to the position X. Sometimes the following relational expression is satisfied.
| D (X) -T (X) | ≦ 7.5 (1)

  According to such a configuration, the thickness characteristic of the glass substrate 1 with the back surface adsorbed onto the surface plate 2 without a gap is defined with reference to the virtual straight line L2. Since this virtual straight line L2 is a straight line, even if it is inclined with respect to the horizontal line, it is easy to adjust the orientation of the coater 3 so as to be parallel to the virtual straight line L2. That is, when the deviation between the virtual straight line L2 and the upper contour line L1 representing the actual surface state of the glass substrate 1 is very small, the two substantially coincide with each other, and the surface of the coater 3 and the glass substrate 1 The distance between can be made almost constant. Therefore, by appropriately managing the distance between the upper contour line L1 and the virtual straight line L2, it is possible to prevent a situation in which the thickness of the coating film formed by the coater 3 varies. And from such a viewpoint, as a result of intensive studies, the inventor has obtained the above formula between the virtual straight line L2 and the upper contour line L1 in the longitudinal section S at any position along the one side 1a. It has been found that if the relationship shown in (1) holds, variations in the thickness of the coating film formed by the coater 3 can be suppressed as much as possible. In other words, it is possible to suppress the variation in the thickness of the coating film as much as possible only after satisfying the above numerical range, and it is not possible to enjoy such operational effects if it deviates from the numerical range.

  In addition, in the longitudinal section S parallel to the other side 1b at any position along the one side 1a, the case where the relationship represented by the above formula (1) is established has been described. It is preferable to be parallel to the drawing direction when the substrate 1 is molded. This is because the glass substrate 1 is manufactured regardless of whether the molten glass is drawn using any of the down draw methods such as the overflow down draw method (fusion method) and the slot down draw method, and the float method. This is because the variation in the plate thickness tends to be small in the plate drawing direction and large in the direction orthogonal to the plate drawing direction. Of course, the relationship represented by the above formula (1) may also be established in a longitudinal section parallel to one side 1a at any position along the other side 1b.

  And the above glass substrates 1 are manufactured as follows.

  First, a forming step is performed in which a glass substrate 1 having a side dimension of 300 mm or more and an average plate thickness of 0.3 to 4.0 mm is formed. Thereafter, when the back surface is adsorbed onto the surface plate 2 without any gap from the glass substrate 1 molded in the molding step before the coating step of forming the coating material on the glass substrate 1 by the coater 3, the orthogonality is obtained. In the longitudinal section S parallel to the other side 1b at any position along either one of the two sides 1a, a selection step is performed for selecting the glass substrate 1 that satisfies the relational expression of the above formula (1). And an application | coating process is performed only with respect to the glass substrate 1 selected by this screening process.

  In this way, the coating process is performed only on the glass substrate 1 that satisfies the relational expression shown in the above formula (1), so that the thickness of the coating film causes an inappropriate variation. It is not necessary to perform the coating process on a glass substrate with poor characteristics. Therefore, it is possible to reliably reduce the economical and time waste required for the coating process performed on a defective glass substrate.

  Further, in the coating process, as shown in FIG. 2, when the coating material is applied by the coater 3, the distance between the coater 3 and both ends A and B of the upper contour line L1 is maintained constant. As shown in FIG. 1, the coater 3 is moved in a direction along one side 1 a of the glass substrate 1 while adjusting the posture (tilt) of the coater 3.

  More specifically, in order to make the distance between the coater 3 and the surface of the glass substrate 1 as constant as possible, the glass substrate 1 in a direction orthogonal to the moving direction of the coater 3 after adsorbing the glass substrate 1 to the surface plate 2. The heights of both ends (both ends A and B of the upper contour line L1) are measured, and the posture of the coater 3 is adjusted based on the measured heights of both ends. The reason for this is that when a plurality of coating steps are included in the manufacturing process of the glass substrate 1, a coating film or a pattern is already formed in the previous step on the center side of both ends of the glass substrate 1. This is because the accurate height of the glass substrate 1 cannot be measured in the central region. Therefore, the posture of the coater 3 is adjusted with reference to the heights of both ends of the glass substrate 1 that can be accurately measured.

  Further, if the orientation of the coater 3 is adjusted in this way, the virtual straight line L2 is a straight line connecting both end portions A and B of the upper contour line L1, and therefore, the coater 3 and both end portions A and B of the upper contour line L1 are connected. The coater 3 can be made parallel to the virtual straight line L2 only by controlling the distance between them to be constant. Therefore, the posture of the coater 3 when applying the coating material to the glass substrate 1 can be maintained within an appropriate range by simple control. And if the unevenness | corrugation of the surface of the glass substrate 1 is managed on the assumption that the attitude | position of the coater 3 is adjusted in this way, since it becomes unnecessary to give the glass substrate 1 an excessive quality, the manufacturing efficiency of the glass substrate 1 is improved. It can also be made.

  In addition, after the coating process, there is a photoresist process in which a coating film formed on the surface of the glass substrate 1 is exposed and developed to form elements or structures such as fine electrodes and partition walls on the surface of the glass substrate 1. Done. At this time, since the thickness of the coating film formed in the coating process is made substantially constant, there is no situation in which a defect such as exposure unevenness caused by a defective film thickness of the coating film occurs in the photoresist process. It becomes possible to form the element or the structure on the surface of the glass substrate 1 with high accuracy.

  Finally, a flat panel display with excellent quality can be manufactured by assembling the two glass substrates 1 on which elements and structures are formed in this manner so as to face each other.

  In order to demonstrate the usefulness of the present invention, a comparison test was conducted. The conditions for the comparison test are as follows.

First, as a glass substrate 1 according to Examples 1 to 9 and a glass substrate 1 according to Comparative Examples 1 to 3, a short side dimension is 500 mm, a long side dimension is 1000 mm, and an average plate thickness is 1. A glass substrate for 8 mm PDP was molded. And in the longitudinal cross section S parallel to the short side 1b in the position for every 10 mm space | interval of the direction along the long side 1a in the state which adsorb | sucked the back surface on the surface plate 2 without gap with respect to each glass substrate 1. The length of the perpendicular line drawn from the upper contour line L1 to the surface plate 2 is measured as a function T (X) of the position X in the direction along the short side 1b, and both ends A and B of the upper contour line L1 are connected. The length of the perpendicular drawn from the virtual straight line L2 to the surface plate 2 was also measured as a function D (X) of the position X. In this embodiment, the position X is defined by the horizontal distance from the end A with the end A of the upper contour L1 as a reference position, and the value is from 0 mm to both ends A of the upper contour L1. , B is a numerical value up to a horizontal distance X ₀ mm (approximately 500 mm). Further, when measuring T (X), a laser plate thickness measuring device was used to measure the length of a perpendicular line dropped from the upper contour line L1 of the glass substrate 1 to the surface plate 2 at each position. On the other hand, when D (X) is D ₁ and D ₂ respectively, the lengths of the perpendiculars drawn on the surface plate 2 at both ends A and B of the upper contour line L1 measured by the laser plate thickness measuring instrument are as follows: It is calculated by the following formula.
D (X) = {D ₁ × (X ₀ −X) + D ₂ × X} / X ₀ (2)

  And on each surface of the glass substrate 1 which concerns on Examples 1-9 and the glass substrate 1 which concerns on Comparative Examples 1-4, a coating film is actually formed with the coater 3, and the film thickness of the formed coating film is set. evaluated. The results are shown in the following table. In the table, the value that maximizes the absolute value of D (X) -T (X) in each glass substrate 1 is shown as the value of D (X) -T (X). Further, in the evaluation of the coating film thickness, the case where the coating film thickness is within ± 5.0% of the average film thickness was evaluated as “◯”, and the case where it deviated from this range was determined as “X”. . The reason for such evaluation criteria is that, if the coating film thickness is not within the range of ± 5.0% of the average film thickness, the variation in the coating film thickness becomes a practical problem. This is because problems such as exposure unevenness are likely to occur when the coating film is exposed and developed by photolithography to perform patterning.

  According to the above results, in the glass substrates 1 according to Comparative Examples 1 to 3 in which the value of | D (X) −T (X) | exceeds 7.5 μm, the coating film thickness does not satisfy the evaluation criteria. became. On the other hand, in the glass substrate 1 which concerns on Examples 1-9 whose value of | D (X) -T (X) | is 7.5 micrometers or less, the favorable result with which a coating film thickness satisfy | fills evaluation criteria was obtained. . Also from this, in the glass substrate 1, if the value of | D (X) −T (X) | is 7.5 μm or less, the glass substrate 1 is in a state where the back surface of the glass substrate 1 is adsorbed to the surface plate 2 without a gap. Even when the coating material is applied to the surface side of the substrate 1 by the coater 3, it can be recognized that the variation in the thickness of the coating film can be suppressed as much as possible.

It is a perspective view which shows typically the state which adsorb | sucked the glass substrate for flat panel displays which concerns on one Embodiment of this invention on a surface plate. It is a longitudinal cross section parallel to the other side in the arbitrary positions along one side of the glass substrate shown in FIG.

Explanation of symbols

1 Glass substrate 2 Surface plate 3 Coater L1 Upper outline L2 Virtual straight line

Claims (6)

It is used for a flat panel display, is a glass substrate having a side dimension of 300 mm or more and an average thickness of 0.3 to 4.0 mm,
When the back surface is adsorbed onto the surface plate without any gap, it is lowered from the upper contour line to the surface plate in the longitudinal section parallel to the other side at any position along one of the two orthogonal sides. The length of the vertical line is expressed by a function T (X) indicated by the relationship with the position X in the direction along the other side, and is lowered from the virtual straight line connecting both ends of the upper contour line to the surface plate. When the length of the perpendicular is expressed by a function D (X) expressed in relation to the position X, a relationship of | D (X) −T (X) | ≦ 7.5 μm is established. substrate.   The glass substrate according to claim 1, wherein the glass substrate is produced by subjecting molten glass to sheet drawing, and the sheet drawing direction is parallel to the other side.   The glass substrate according to claim 1, wherein the glass substrate is used for a plasma display, a field emission display, or a liquid crystal display.   A flat panel display manufactured using the glass substrate according to claim 1. A flat panel display is used to form a glass substrate having a side dimension of 300 mm or more and an average plate thickness of 0.3 to 4.0 mm. A method of manufacturing a glass substrate having a coating step of forming a coating film on the surface of the glass substrate while moving a coater for coating a coating material while adsorbed on the coating material,
When the back surface is adsorbed onto the surface plate without a gap from the glass substrate molded in the molding step between the molding step and the coating step, either one of the two orthogonal sides In a vertical section parallel to the other side at any position along the side, a function T indicating the length of a perpendicular line drawn from the upper contour line to the surface plate in relation to the position X in the direction along the other side. (X), and when the length of a perpendicular drawn from the virtual straight line connecting both ends of the upper contour line to the surface plate is represented by a function D (X) in relation to the position X, | D (X) −T (X) | ≦ 7.5 μm including a sorting step for selecting a glass substrate, and performing the coating step only on the glass substrate selected in the sorting step A method for producing a glass substrate, comprising:   In the application step, when the coating material is applied by the coater, the coater is adjusted while adjusting the posture of the coater so that the distance between the coater and both ends of the upper contour line is constant. The method for manufacturing a glass substrate according to claim 5, wherein the glass substrate is moved in a direction along the one side of the glass substrate.

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