JP2008135337A - Glass spacer for flat display, and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a glass spacer for a flat display allowing a glass spacer of a nearly-oblong cross-sectional shape formed by optimizing the difference between the thickest part in the vicinities of both ends of a long side and the thinnest part in the vicinity of the center; and its manufacturing method. <P>SOLUTION: An end of a glass base material 10 of an oblong cross section having a width of 60-180 mm is sequentially heated and melted to be continuously linearly drawn into a generally similar shape, and formed into this spacer 12 of a nearly-oblong cross-sectional shape where its center is recessed, and the difference between the thickest part in the vicinities of both ends of a long side and the thinnest part in the vicinity of the center is not smaller than 10 μm and smaller than 45 μm. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for producing a glass spacer for flat display, and more particularly to a glass spacer for flat display and a method for producing the same by melting and stretching a glass base material.

  The flat panel display (FPD) is expected to expand greatly in the future with the spread of digital broadcasting and broadband, and the field emission display is being developed for practical use as one of the FPDs. Yes.

  This FED is composed of a front glass substrate on the inner surface of which a phosphor for image formation that generates visible light upon incidence of electrons is formed, and a rear glass substrate on which electron-emitting devices are arranged in a matrix. A plurality of glass spacers are provided between the glass substrates in order to maintain a high vacuum between the substrates and to support the glass substrates from atmospheric pressure.

  The glass spacer has a height (width) of 1 to 5 mm and a thickness of 0.03 to 0.30 mm. For example, glass spacers having a width of 2 mm and a thickness of 150 μm are being manufactured.

  By the way, it is already known that a glass spacer for a flat display is manufactured by melting and stretching a glass base material.

  For example, in Patent Document 1, a raw material rod (base material) having a polygonal cross section whose side has been polished in advance is coupled to a mechanical equipment that can be vertically lowered, and inserted and melted sequentially from the lower end into a ring-shaped heating device. The heating device can be adjusted to ± 0.1 ° C. using a low-voltage hot wire as a heat source. And the method of extending | stretching with a pair of drive belt installed below the heating apparatus is proposed.

  Patent Document 2 also proposes a spacer manufacturing method by melting and stretching. The installed base glass is sequentially fed into the heating furnace from the lower end while controlling the supply speed by driving the motor. The heating furnace has a substantially rectangular cross section and is provided with two pairs of heaters. Each heater pair is independently controlled by each control device. On the other hand, a pair of stretching rolls is installed immediately below the heating furnace, and stretches at a predetermined stretching speed while sandwiching the spacer glass drawn from the heating furnace.

Japanese Patent Application Laid-Open No. 07-144939 JP 2004-014199 A

  However, there is no description regarding a slight difference between the cross-sectional shape of the base material and the cross-sectional shape of the spacer after drawing.

  Although the manufacturing method by the drawing method is suitable for reducing the cost of the spacer, it is effective to increase the size of the base material and increase the drawing speed in order to further reduce the cost.

  With respect to the cross-sectional shape of the spacer after drawing, Patent Document 3 proposes various shapes. However, a detailed study on the drawing productivity of the glass spacer, including this known example, has not been made so far.

  The cross-sectional shape of a conventional spacer is substantially rectangular, and the shape of which the thickness of both ends of the long side is slightly larger than that of the central part is considered to have the best characteristics when mounted on an FED panel. In order to manufacture, at the initial stage of development, as shown in FIG. 4, the center portion is formed by cutting with a ball end mill blade on both sides of a rectangular cross section glass base material having a width of 30 mm, a thickness of 2.4 mm, and a length of 1000 mm. Then, a concave surface 31 having a depth of 0.15 mm was provided to form a base material 30, which was drawn to form a spacer 32 having a width of 2.0 mm, a maximum thickness of both ends of 0.15 mm, and a central portion thickness of 130 μm.

  However, since the concave surface is formed on the rectangular cross-section glass base material by cutting, there is a problem that the processing cost increases compared to a simple rectangular cross-section base material.

  Therefore, the object of the present invention is to eliminate the drawbacks of the prior art described above, and optimize the difference in thickness between the thickest part near both ends of the long side and the thinnest part near the center. An object of the present invention is to provide a glass spacer for flat display and a method for manufacturing the same, which can manufacture a glass spacer having a cross-sectional shape at a low cost.

  In order to achieve the above object, the invention of claim 1 is to heat and melt the glass base material end of a rectangular cross section having a width of 60 mm to 180 mm in order, and draw it continuously in a substantially similar shape. A method for producing a glass spacer for a flat display, characterized in that the difference in thickness between the thickest part in the vicinity and the thinnest part in the vicinity of the center is formed in a substantially rectangular cross-sectional shape having a depressed center with a thickness of 10 μm or more and less than 45 μm.

  In the invention of claim 2, the glass base material is made of conductive glass containing a transition metal oxide, and the glass base material has a rectangular cross-sectional shape with a width of 60 mm to 150 mm, and a drawing speed according to the width. 2. The substantially rectangular cross-sectional shape in which the difference between the thickness of the thickest part near both ends of the long side and the thinnest part of the center is 10 μm or more and less than 45 μm is recessed. It is a manufacturing method of the glass spacer for flat type displays.

  The invention according to claim 3 is the glass for flat display according to claim 2, wherein the transition metal oxide contained in the conductive glass is mainly composed of an oxide made of a transition metal such as tungsten, vanadium, barium or niobium. It is a manufacturing method of a spacer.

  According to a fourth aspect of the present invention, the glass base material is made of insulating glass, and the glass base material has a rectangular cross-sectional shape with a width of 80 mm to 180 mm. The glass base material is drawn at a drawing speed corresponding to the width. 2. The glass spacer for a flat display according to claim 1, wherein the difference in thickness between the thickest portion near both ends of the side and the thinnest portion near the center is formed in a substantially rectangular cross-sectional shape with the center being 10 μm or more and less than 45 μm. It is a manufacturing method.

  According to a fifth aspect of the present invention, the insulating glass contains silicon oxide, aluminum oxide, alkaline earth metal oxide, and alkali metal oxide, and more preferably an aluminosilicate glass or an aluminoborosilicate glass as a main component. The method for producing a glass spacer for a flat display according to claim 4.

  Invention of Claim 6 is manufactured by the manufacturing method of the glass spacer for flat displays in any one of Claims 1-5, and the cross-sectional shape is a substantially rectangular shape in which the center was depressed, and the thickest part near both ends of a long side And a difference in thickness of the thinnest part in the vicinity of the center is 10 μm or more and less than 45 μm.

  According to the present invention, the difference in thickness between the thickest part near both ends of the long side and the thinnest part near the center is 10 μm or more by drawing using a glass base material having a rectangular section with a width of 60 to 180 mm. A glass spacer having a substantially rectangular cross section with a depressed center of less than 45 μm can be drawn in mass production. In addition, since the processing cost of the base material can be reduced and high-speed drawing with a large base material can be performed, a low-cost glass spacer can be provided.

  A preferred embodiment of the present invention will be described below in detail with reference to the accompanying drawings.

First, as a result of the inventors examining the shape of the glass spacer, the cross-sectional shape of the spacer is substantially rectangular, and the thickness (t _max ) at both ends of the long side is slightly larger than the central portion (t _min ). When mounted on an FED panel, various characteristics were found to be the best.

Specifically, in the case of a glass spacer having a long side of 2.0 to 3.0 mm and a short side of 0.15 mm, 10 μm <{(t _max ) − (t _min )} <45 μm
The range of was suitable.

  The basis for this optimum numerical range is as follows.

  In the case where the spacer thickness difference is 10 μm or less, the beam trajectory of electrons emitted from the emitter near the spacer tends to be disturbed depending on the applied voltage in the completed FED panel. Therefore, an afterimage of the spacer may be seen when the panel is turned on. In the vicinity of the central portion in the spacer height direction, it is preferable that the spacer thickness is slightly smaller so as to be away from the electron beam trajectory.

  On the other hand, when the spacer thickness difference is 45 μm or more, the thickness of the central portion is 100 μm or less, the buckling strength is reduced in the long side (width) direction, and the inside of the panel is evacuated in the FED panel manufacturing process. Some spacers were buckled and destroyed. In addition, when mounting a spacer on the panel, a vacuum chuck type gripper was used to transport the spacer, and the side of the spacer was concave, so the entire tip of the gripper was not in close contact with the spacer, causing a vacuum leak and the chuck part Sometimes dropped out.

  Therefore, it has been found that the difference in thickness between the thickest part near both ends of the long side and the thinnest part near the center is preferably 10 μm or more and less than 45 μm.

  Furthermore, in the present invention, by drawing using a relatively large glass base material having a width of 60 mm to 180 mm, the thickest part near the both ends of the long side of the spacer cross section after drawing by the thermal process during drawing and the vicinity of the center It was newly found that the thickness difference can be made 10 μm or more and less than 45 μm depending on the drawing conditions.

  Next, a drawing apparatus for drawing a glass spacer according to the present invention will be described with reference to FIG.

An aluminosilicate glass base material 10 having a width (W ₀ ) of 120 mm, a thickness (t ₀ ) of 10.5 mm, and a length of 1200 mm is connected to a base material gripping part 20 capable of precisely descending vertically. The core is inserted into the drawing furnace 21 that has been heated to about 760 ° C. in advance.

  The surface of the base material 10 is polished by mechanical grinding until the arithmetic average surface roughness Ra becomes about 1.0 μm.

  The drawing furnace 21 is a high-purity carbon muffle furnace having an inner diameter of 140 mm, and He gas is introduced into the core through a mass flow controller to prevent oxidative degradation.

  The base material gripping part 20 is driven by a servo motor, and the base material 10 is fed into the drawing furnace 21 at a constant speed of 12 mm / min. A laser-type outer diameter measuring device 22 is installed immediately below the drawing furnace 21, and a take-up roll 23 is installed therebelow.

  The base material 10 melted in the wire drawing furnace 21 is taken out from the furnace lower opening while maintaining its cross-sectional shape, and is sandwiched and taken up at a speed of about 50 m / min by a take-up roll 23 arranged oppositely.

  The outer diameter measuring device 22 is installed so that the laser irradiation direction is orthogonal to the glass spacer plate width surface, and always measures the width dimension of the glass spacer 12.

The dimensional data of the spacer 12 measured by the outer diameter measuring device 22, particularly a deviation signal from a reference value (for example, W ₁ = 2.0 mm) is fed back to the take-up roll 23 through the control panel 24, and the outer diameter (width) of the glass spacer 12 is measured. The speed of the roller is finely controlled so that the

The cross-sectional dimension of the drawing spacer was uniform over the entire length of the glass spacer after drawing, and the thickness t ₁ = 150 μm at both ends and 128 μm at the center (FIG. 2).

As shown in Table 1 and Table 2, the glass spacer is drawn using a rectangular cross-section base material made of various glass materials having different cross-sectional dimensions, and the thickness t _max of the end portion of the obtained spacer and the thickness of the central portion are obtained. The difference from t _min (t _max −t _min ) was evaluated.

  Two types of glass materials were used: insulating glass and conductive glass.

  Specifically, the insulating glass is an aluminosilicate glass, and the conductive glass is an iron oxide-containing silica glass.

  In order to make the melting time of the glass base material in the drawing furnace constant, the feeding speed of the base material was constant at 12 mm / min.

FIG. 3 shows the relationship between the width dimension of various base materials and the thickness difference (t _max −t _min ) of the glass spacer obtained after drawing.

  It can be seen that the thickness difference of the glass spacer increases as the width of the base material increases.

  In particular, from the viewpoint of the glass material, the difference in thickness is greater when the conductive glass has the same width than the insulating glass. When the glass material is insulating glass, as shown in Table 1, by using a base material having a width of 80 to 180 mm and drawing the drawing speed in the range of 21 to 133 m / min, the end and the center are drawn. A glass spacer having a thickness difference of 10 μm or more and 45 μm or less can be obtained.

  Further, when the glass material is conductive glass, by drawing a base material having a width of 60 to 150 mm as shown in Table 2 within a drawing speed range of 11 to 85 m / min, A glass spacer having a thickness difference of 10 μm to 45 μm can be obtained.

  In addition, the reason why the thickness is thinner at the center than at both ends after the spacer is formed is that a difference in glass viscosity occurs in the horizontal direction at the glass solidification start position slightly below the maximum temperature position in the drawing furnace 21. is there. Since the base material 10 used for the glass spacer is plate-shaped, it is cooled first from both ends having a large surface area in the cooling process. That is, since the drawing tension is applied in a state where the viscosity is high at both ends and low at the center, the deformation progresses more and the thickness decreases at the center where the viscosity is low.

  On the other hand, the difference due to the glass material is not due to the presence or absence of electronic conductivity, but due to the difference in thermal conductivity.

  The thermal conductivity of the glass mainly composed of silicon oxide in the present invention is 1.0 to 1.5 (W / m · K), whereas it is 0 for the conductive glass mainly composed of a transition metal oxide. .5 to 0.8 (W / m · K) and small. Therefore, even with a base material having the same cross-sectional dimensions, the conductive glass has a larger temperature difference in the horizontal direction, that is, a difference in viscosity of the glass in the above-described cooling process, resulting in a larger thickness difference in the glass spacer.

  It is desirable that the transition metal oxide contained in the electron conductive glass is based on a glass material whose main component is an oxide composed of a transition metal such as tungsten, vanadium, barium, or niobium.

  In addition, the material of the insulating glass is desirably glass mainly composed of silicon oxide. Specifically, a glass containing at least silicon oxide, aluminum oxide, alkaline earth metal oxide, or alkali metal oxide. More desirable are aluminosilicate glass, aluminoborosilicate glass, and the like, which are difficult to cause diffusion of alkali ions and collapse of the glass structure due to electron irradiation, and can be said to be suitable glass materials for glass spacers for FED panels. .

  Although the glass spacer having the long side of 2.0 mm and the short side of 0.15 mm has been described above, the optimum range of the thickness difference is almost the same for the spacer having the long side of 3.0 mm and the short side of 0.15 mm.

  In the embodiment of the present invention, the feeding speed of the base material is 12 mm / min. However, even when the feeding speed is changed within a range of 3 to 25 mm / min for each base material, The difference in thickness between the end portion and the central portion was in the range of 10 μm or more and 45 μm or less. In addition, if the feeding speed of the base material is less than 3 mm / min, the curvature of the four corners of the spacer becomes large and the panel assemblability deteriorates, and if it exceeds 35 mm / min, the heating of the base material in the drawing furnace cannot catch up, The glass cannot be melted or drawn smoothly.

In this invention, it is the schematic of a glass spacer drawing apparatus. It is sectional drawing of the glass spacer drawn by this invention. It is a figure which shows the correlation of the base material width | variety and the thickness difference of the glass spacer drawn by it. It is the base material cross-sectional dimension by a prior art, and the glass spacer cross-sectional dimension after drawing.

Explanation of symbols

10 Base Material 12 Glass Spacer 21 Drawing Furnace 23 Take-up Roll

Claims (6)

  Thickness of the thickest part near both ends of the long side and the thinnest part near the center of the glass base material with a width of 60 mm to 180 mm is sequentially heated and melted and continuously drawn in a similar shape. A method for producing a glass spacer for a flat display, characterized in that the difference in thickness is formed in a substantially rectangular cross section with a depressed center having a difference of 10 μm or more and less than 45 μm.   The glass base material is made of conductive glass containing a transition metal oxide, and the glass base material has a rectangular cross-sectional shape with a width of 60 mm to 150 mm. The glass base material is drawn at a drawing speed according to the width, 2. The glass spacer for a flat display according to claim 1, wherein the difference in thickness between the thickest portion near both ends of the side and the thinnest portion near the center is formed in a substantially rectangular cross-sectional shape with the center being 10 μm or more and less than 45 μm. Production method.   The method for producing a glass spacer for a flat display according to claim 2, wherein the transition metal oxide contained in the conductive glass is mainly composed of an oxide composed of a transition metal such as tungsten, vanadium, barium, or niobium.   The glass base material is made of insulating glass, and the glass base material has a rectangular cross-sectional shape with a width of 80 mm to 180 mm. The glass base material is drawn at a drawing speed corresponding to the width, and the maximum thickness near both ends of the long side. 2. The method for producing a glass spacer for a flat display according to claim 1, wherein the difference in thickness between the portion and the thinnest portion in the vicinity of the center is formed in a substantially rectangular cross-sectional shape in which the center is depressed in the range of 10 to 45 [mu] m.   5. The planar surface according to claim 4, wherein the insulating glass contains silicon oxide, aluminum oxide, alkaline earth metal oxide, and alkali metal oxide, and more preferably, the main component is aluminosilicate glass or aluminoborosilicate glass. Of manufacturing glass spacer for flat panel display.   It is manufactured by the method for manufacturing a glass spacer for a flat display according to any one of claims 1 to 5, wherein the cross-sectional shape is a substantially rectangular shape with a depressed center, and the thickest portion near both ends of the long side and the thinnest portion near the center. The difference in thickness of the part is 10 μm or more and less than 45 μm, a glass spacer for flat display.

Images