JP2004071161A - Manufacturing method of spacer, and spacer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a simple manufacturing method of a spacer capable of forming a part with relatively low electric resistance for preventing electrification of the surface area of the spacer with good controllability, and to provide the spacer. <P>SOLUTION: The manufacturing method of the spacer comprises a process of forming a spacer base body made of glass material of which at least a part of the surface area contains PbO by 40 wt.% or more, and a process of lowering the resistance of at least a part of the surface area by deoxidizing the spacer base body. The conductivity of the surface of the spacer can be easily controlled only by changing at least one condition out of the setting of the amount of PbO contained in the glass material, the temperature and the period of deoxidization, and the hydrogen density of the deoxidizing atmosphere. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method of manufacturing a spacer for supporting an electron source in which an electron source is hermetically sealed between a pair of substrates. More specifically, the present invention relates to a method for manufacturing a spacer in which a portion having relatively low electric resistance is formed on a surface portion for the purpose of preventing static charge or the like, and is disposed between a pair of substrates, for example, a panel display.
[0002]
[Prior art]
In recent years, surface-conduction type electron-emitting devices are arranged in a matrix on a substrate, and emitted electrons are radiated to phosphors provided on a substrate facing each other so as to hermetically seal the electron-emitting devices to form an image. The development of a panel-shaped display to be formed is in progress.
[0003]
Such a method of manufacturing a spacer that supports between the substrates of an electron beam device in which an electron source is hermetically sealed between a pair of substrates includes a method of rotating a glass base material by rotating a delivery roller sandwiching the glass base material. On the other hand, while sending out, sandwiching the sent glass base material between the take-up rollers, withdrawing at a take-up speed higher than the sending speed of the sending roller, heating and softening the glass base material between the sending roller and the take-up roller, and There is known a heat stretching method in which the stretched base material is stretched by a difference in speed between a feeding speed and a take-up speed by a take-off roller, and the stretched stretched base material is cut into a plate-like or column-like spacer having a desired thickness.
[0004]
[Problems to be solved by the invention]
On the other hand, the spacer used in such an electron beam device is charged by a part of the electrons emitted from the electron source hitting the spacer, or the ions ionized by the action of the emitted electrons adhere to the spacer. It is pointed out that it may cause it. When the spacer is charged, the trajectory of the electrons emitted from the electron source cannot be accurately controlled, which leads to a problem that a displayed image is distorted, for example.
[0005]
In order to solve such a problem, an antistatic film is provided on the surface of the spacer, which is a portion having a relatively low electric resistance to quickly release the charged charges to the outside and prevent the charging, thereby reducing the charging of the spacer. Techniques for preventing this are disclosed in JP-A-57-118355, JP-A-61-124031, and the like. In addition, as a technique for efficiently manufacturing a spacer having such an antistatic film in a smaller number of steps, the above-described heating and stretching method is applied, and a conductive material is sprayed on the base material surface of the spacer while performing heating and stretching. A method of applying the material is disclosed in JP-A-2000-31605.
[0006]
An object of the present invention is to form a portion having a relatively low electric resistance for antistatic at a surface layer portion of a spacer with good controllability by a method different from the above-described conventional method, and to provide a simpler spacer. And a spacer.
[0007]
[Means for Solving the Problems]
A first aspect of the present invention for solving the above-mentioned problems is as follows.
Forming a spacer substrate made of a glass material containing at least a part of the surface layer portion containing 40% by weight or more of PbO;
A step of reducing the resistance of at least a part of the surface layer portion by reducing the spacer substrate,
A method for producing a spacer, comprising:
"In the step of forming the spacer substrate, a glass base material using a glass material containing PbO in an amount of 40% by weight or more in at least a part of the surface layer portion is heated and stretched, and the stretched stretched glass base material is stretched to a required length. To form a spacer substrate by cutting into pieces. "
"The glass base material has a cross-sectional shape with different vertical and horizontal dimensions,
A composite comprising the glass base material, a core glass material disposed in an inner layer of the glass base material, and a surface glass material disposed in a region including an outer surface along at least a cross-sectional longitudinal direction of a surface layer portion of the glass base material. Structure and
That the surface glass material is made of a glass material containing 40% by weight or more of PbO ”as a preferred embodiment thereof.
[0008]
The present invention provides, in the above first invention,
"The cross-sectional shape of the core glass material is rectangular, and the surface glass material uses a glass base material addressed to at least two surfaces on the long side of the cross-section of the core glass material."
"In the step of lowering the resistance, at least a part of the resistivity of the surface glass material integrated on the two surfaces on the longer side of the cross section of the core glass material is 10 ⁸ -10 ¹⁰ Ω · cm ”
"Surface glass material further uses a glass base material addressed to two surfaces on the short side of the cross section of the core glass material."
"The surface glass material addressed to the two short-side sides of the core glass material is made of a glass material containing 60% by weight or more of PbO."
"In the step of lowering the resistance, the resistivity of at least a part of the surface glass material integrated with the two surfaces on the short side of the cross section of the core glass material is 10%. ³ -10 ⁴ Ω · cm ”
Is included as a preferable embodiment.
[0009]
Further, the present invention provides, in the first aspect,
"Surface glass material, using a glass base material including a member having a plurality of grooves along the stretching direction on the outer surface side",
"Use a glass base material in which the cross-sectional shape of the core glass material is rectangular, and the surface glass material having a plurality of grooves on the outer surface along the stretching direction is directed to two surfaces on the longer side of the cross-section of the core glass material. "
"The surface glass material addressed to the two surfaces on the longer side of the cross section of the core glass material includes a plurality of thin plate members, the thin plate members having the same width as the pitch of the plurality of grooves, Having two different thicknesses corresponding to the peaks and valleys ",
"In the step of lowering the resistance, at least a part of the resistivity of the surface glass material integrated on the two surfaces on the longer side of the cross section of the core glass material is 10%. ⁸ -10 ¹⁰ Ω · cm ”
"Surface glass material further uses a glass base material addressed to two surfaces on the short side of the cross section of the core glass material."
"The surface glass material addressed to the two short-side sides of the core glass material is made of a glass material containing 60% by weight or more of PbO."
"In the step of lowering the resistance, the resistivity of at least a part of the surface glass material integrated with the two surfaces on the short side of the cross section of the core glass material is 10%. ³ -10 ⁴ Ω · cm ”
Is included as a preferable embodiment.
[0010]
By the way, in general, when a glass material is stretched, the viscosity of the glass material becomes ⁵ -10 ¹⁰ Heating is performed so as to be in the range of dPa · s.
[0011]
Also in the above conventional manufacturing method, the viscosity of the glass base material is 10 ⁵ -10 ¹⁰ Stretching is performed by heating so as to be in the range of dPa · s. However, when the stretching is performed with the viscosity set lower, that is, when the heating temperature is increased, as shown in FIG. Both ends of the spacer in the longitudinal direction of the cross section are rounded and easily swell. When such a swelling occurs, when the obtained thin plate-shaped spacer is installed vertically on the substrate, the contact surface with the substrate is curved, so that the stability is poor and the assembling property is poor. In addition, there is a problem that it is difficult to obtain the supporting strength.
[0012]
When stretching is performed with a higher viscosity, that is, when stretching is performed at a lower heating temperature, as shown in FIG. 16, an intermediate portion of the obtained thin plate-shaped spacer in the longitudinal direction of the cross section is easily constricted. When such constriction occurs, the desired strength cannot be obtained.For example, when used as a spacer disposed between a pair of front and back substrates of a panel-shaped display, the pressure between the pair of substrates is reduced. In some cases, high atmospheric pressure resistance cannot be obtained.
[0013]
It is considered that the cause of the occurrence of the swelling or constriction is that both ends in the longitudinal direction of the cross section are more likely to be heated when the glass base material having a different cross-sectional shape in vertical and horizontal dimensions is heated than in the intermediate portion. For example, in a glass base material having a rectangular cross section, if a surface along the longitudinal direction is a long surface and a surface along the short direction is a short surface, an intermediate portion in the cross section is heated by heat from the long surface. On the other hand, both ends in the cross-section longitudinal direction are heated by receiving heat from both the long side and the short side, and are more likely to be heated as compared with the intermediate part. For this reason, if it is attempted to heat the entire length of the glass base material in the cross-sectional longitudinal direction to a state where the glass base material has a viscosity that facilitates stretching, it is considered that the heating of the both ends becomes excessive, the viscosity is reduced, and swelling is caused. Further, if the heating temperature is lowered to suppress the bulging, the heating of the intermediate portion becomes insufficient, the viscosity of the intermediate portion increases, and the concentration of stress during stretching is considered to cause necking.
[0014]
In order to solve this, the present invention provides, in the first invention,
"In the step of forming the spacer substrate, the glass base material is made to have a viscosity of 10% for both the core glass material and the surface glass material. ⁵ -10 ¹⁰ Heating and stretching to a stretching temperature within the range of dPa · s and the viscosity of the surface glass material higher than the viscosity of the core glass material ”,
Is included as a preferable embodiment.
[0015]
The second aspect of the present invention is as follows.
A spacer characterized in that at least a portion of a surface layer portion has a portion whose resistance is reduced by reducing a glass material containing PbO.
[0016]
A third aspect of the present invention is
The spacer has a composite structure in which a core glass material disposed in an inner layer of the spacer and a surface glass material disposed in a region including an outer surface along at least a cross-sectional longitudinal direction in a surface layer portion of the spacer are integrated. A spacer characterized in that at least a part of the surface glass material has a portion whose resistance is reduced by reducing a glass material containing PbO.
[0017]
The present invention provides, in the above third invention,
"The cross-sectional shape of the core glass material is rectangular, and the surface glass material is integrated with at least two surfaces on the long side of the cross section of the core glass material, and the surface glass material integrated on the two surfaces on the long side of the cross section At least a portion of which has a portion that has been reduced in resistance by reducing a glass material containing PbO ”;
"The resistivity of the low-resistance portion of the surface glass material integrated with the two surfaces on the longer side of the cross section of the core glass material is 10%. ⁸ -10 ¹⁰ Ω · cm ”,
"A glass material in which a surface glass material is further integrated on two surfaces on the short side of the cross section of the core glass material, and at least a part of the surface glass material integrated on the two surfaces on the short side of the cross section contains PbO. To have a part whose resistance has been reduced by reduction treatment ”,
"The resistivity of the low-resistance portion of the surface glass material integrated on the two surfaces on the short side of the cross section of the core glass material is 10%. ³ -10 ⁴ Ω · cm ”,
Is included as a preferable embodiment.
[0018]
Further, the present invention provides the above-mentioned third invention, wherein:
"Surface glass material includes a portion having a plurality of grooves on the outer surface side along the stretching direction",
"The cross-sectional shape of the core glass material is rectangular, and the surface glass material having a plurality of grooves along the stretching direction on the outer surface side is integrated with two surfaces of the core glass material on the longer side of the cross section. That at least a part of the surface glass material integrated on the two surfaces has a portion reduced in resistance by reducing the glass material containing PbO ”;
"The resistivity of the low-resistance portion of the surface glass material integrated with the two surfaces on the longer side of the cross section of the core glass material is 10%. ⁸ -10 ¹⁰ Ω · cm ”,
"A glass material in which a surface glass material is further integrated on two surfaces on the short side of the cross section of the core glass material, and at least a part of the surface glass material integrated on the two surfaces on the short side of the cross section contains PbO. To have a part whose resistance has been reduced by reduction treatment ”,
"The resistivity of the low-resistance portion of the surface glass material integrated on the two surfaces on the short side of the cross section of the core glass material is 10%. ³ -10 ⁴ Ω · cm ”,
Is included as a preferable embodiment.
[0019]
Further, the present invention provides the above-mentioned third invention, wherein:
"The core glass material and the surface glass material have a viscosity of 10 ⁵ -10 ¹⁰ When heated to a temperature in the range of dPa · s, the viscosity of the surface glass material is higher than the viscosity of the core glass material.
Is included as a preferable embodiment.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
The method for producing a spacer according to the present invention includes a step of forming a spacer substrate made of a glass material in which at least a part of the surface layer portion contains PbO in an amount of 40% by weight or more, and a step of reducing the spacer substrate to at least one of the surface layer portions. And reducing the resistance of the part.
[0021]
As used herein, the term “spacer substrate” refers to an intermediate member that is to become a spacer finally after the reduction treatment. The spacer substrate may be composed of a single type of material, or may be of a composite structure divided into a core glass material and a surface glass material as in a preferred embodiment described later. In any case, it is sufficient if at least a part of the surface layer portion is made of a glass material containing PbO at 40% by weight or more (hereinafter abbreviated as PbO-containing glass). That is, the entire spacer substrate may be made of PbO-containing glass, or when a plurality of layers are used, only the surface glass material may be made of PbO-containing glass. The glass material containing PbO at such a ratio can be easily reduced in resistance by a reduction treatment such as hydrogen reduction.
[0022]
The portion made of PbO-containing glass of the spacer substrate does not necessarily need to be formed on the entire surface of the surface layer portion, but at least the portion that is to be exposed when the completed spacer is placed in a state supporting the substrates. The surface layer is preferably made of the PbO-containing glass. Incidentally, the low resistance portion usually provided for preventing charging is provided over a contact portion with another member which comes into contact with the spacer in order to allow electric charges to flow out.
[0023]
In the reduction treatment of the spacer substrate, at least a part of the portion made of the PbO-containing glass is subjected to a reduction treatment to reduce the resistance to a necessary and sufficient degree to appropriately discharge the charged charges to the outside.
[0024]
The PbO-containing glass is not particularly limited as long as it contains 40% by weight or more of PbO, but a glass material of the same type as that of the substrate is preferable so that no thermal stress is generated between the glass and the substrate. .
[0025]
Although there is no particular limitation on the reduction apparatus for the reduction treatment, an apparatus capable of performing the heat treatment in a reducing agent atmosphere such as hydrogen as shown in FIG. 1 is preferable for performing the reduction treatment promptly. .
[0026]
FIG. 1 is an explanatory diagram for explaining an example of a method for reducing a spacer base according to the present invention. In FIG. 1, reference numeral 11 denotes a spacer base, 31 denotes a container in which the spacer base 11 is arranged and the inside of which is set to a predetermined hydrogen concentration atmosphere, 32 denotes a heater for heating the spacer base 11 in the container 31, and 33 denotes a heater 32. This is a reflecting mirror for efficiently transmitting heat into the container 31.
[0027]
The spacer substrate 11 is arranged in the reduction treatment apparatus as shown in FIG. 1, and the hydrogen flow rate in the container is set to 0.5 to 2 l / min.
[0028]
When the atmosphere in the container is prepared, the heating temperature is set to 450 to 550 ° C., and the reduction treatment is performed for 1 to 2 hours. Thereby, the resistance of the surface layer portion of the spacer base 11 can be reduced, and a spacer having an antistatic function can be manufactured.
[0029]
According to such a method of the present invention, it is possible to form a portion having a relatively low electric resistance for preventing charging on the surface layer portion at low cost, easily, and with good controllability. In other words, by using a reducing device that is easy to maintain and does not require much frequency, it is possible not only to reduce the cost of manufacturing a spacer having an antistatic function, but also to reduce the amount of PbO contained in the glass material. By simply changing at least one of the following conditions: reduction temperature, reduction time, hydrogen concentration in the reduction treatment atmosphere, etc., the resistance value of the spacer surface layer can be easily controlled. In addition, since it is relatively easy to maintain the spatial uniformity of the atmosphere in the reduction device, it is expected that a low-resistance portion for preventing electrification can be formed with higher uniformity.
[0030]
Next, a preferred embodiment of the method for forming a spacer substrate according to the present invention will be specifically described with reference to the drawings, but the present invention is not limited thereto.
[0031]
In the step of forming the spacer substrate, the glass substrate is heated and stretched using PbO-containing glass for at least a part of the surface layer portion, and the stretched glass substrate is cut into a required length to form the spacer substrate. The method of forming is mentioned as a simple preferable manufacturing method.
[0032]
FIG. 2 is an explanatory view showing an example of a method of forming a spacer substrate in the present invention, FIG. 3 is a partially enlarged view of the glass base material shown in FIG. 2, and FIG. 4 is a spacer substrate in the present invention obtained by the method in FIG. It is an expansion perspective view of. Since this is subjected to a reduction treatment to produce a spacer, the shape is hardly changed, and FIG. 4 is a view also showing the shape of the spacer.
[0033]
In FIG. 2, reference numeral 1 denotes a glass base material, and as shown in an enlarged manner in FIG. 3, the glass base material 1 is a core glass material 2 having a rectangular cross section (a cross section in a direction perpendicular to the stretching direction of the glass base material 1). And a plate-shaped surface glass material 3 having a rectangular cross-section, which covers the surfaces along the cross-section longitudinal direction (two surfaces on the long side of the cross-section) and sandwiches the core glass material 2 so that the cross-section is rectangular as a whole. It is a combination.
[0034]
Although the cross-sectional shape of the glass preform 1 in this example is rectangular, the present invention is not limited to the glass preform 1 having such a cross-sectional shape, and may be a circle or a rectangle. However, the glass base material 1 preferably has a cross-sectional shape having different vertical and horizontal dimensions as in this example, and may have, for example, an elliptical or trapezoidal cross-sectional shape. Such a spacer obtained from a glass base material having a cross-sectional shape having different vertical and horizontal dimensions has a different vertical and horizontal dimension of the cross-sectional shape while maintaining a similar shape, and the cross-sectional longitudinal direction is substantially perpendicular to the substrate on the substrate. It is only necessary to lay them down so that the manufacturing process can be simplified. In addition, the rectangle in this specification includes not only a shape in which four corners intersect at a right angle but also a shape in which a corner is chamfered or rounded (R-processed). However, in order to obtain a spacer that stably supports between the substrates, a preferred form is a rectangular section.
[0035]
In addition, the glass base material does not necessarily need to be composed of the core glass material and the surface glass material, and may be entirely PbO-containing glass, but by having a composite structure composed of the core glass material and the surface glass material, The selectivity of the material is expanded. That is, the material selection criterion of the core glass material mainly includes the strength and the coefficient of thermal expansion (considering the thermal stress relationship with the substrate) and the like, and the surface glass material can be PbO-containing glass.
[0036]
The combination of the core glass material 2 and the surface glass material 3 may be any of a pressed state, a fitted state, and a bonded state. In this example, as shown in FIG. 2, the core glass material 2 and the surface glass material 3 are combined in a state where they are pressed against each other by tightening the periphery of the glass base material 1 with the mechanical chuck 4.
[0037]
The glass constituting the core glass material 2 can be selected from, for example, elemental glass, oxide glass, fluoride glass, chloride glass, sulfide glass and the like according to the application. Among these, oxide glass (for example, silicate glass, phosphate glass, borate glass, borosilicate glass, etc.) is preferable from the viewpoint of processability.
[0038]
The same glass as the core glass material can be used for the glass constituting the surface glass material 3, but a glass material having a composition containing at least 40% by weight or more of PbO is used.
[0039]
In the example shown in FIG. 2, a glass base material 1 in which the core glass material 2 and the surface glass material 3 are combined is used. The glass base material 1 is clamped and held by a mechanical chuck 4, and a lower portion is heated by a heater 6. The lower part of the stretched drawn glass base material 1 ′ is sandwiched between the take-up rollers 5. In this state, while gradually lowering the mechanical chuck 4, the take-off roller 5 is rotated to take out the drawn glass base material 1 ′ at a take-up speed higher than the descending speed of the mechanical chuck 4, and the mechanical chuck 4 and the take-up roller 5 In the meantime, the glass base material 1 is heated to the stretching temperature by the heater 6 and softened. Then, the speed difference between the descending speed of the mechanical chuck 4 and the take-up speed of the take-off roller 5 causes the glass base material 1 heated to the drawing temperature and softened to be drawn, and the core glass material 2 and the surface glass material 3 are integrated. Thus, a stretched glass base material 1 ′ having a cross-sectional shape substantially similar to that of the glass base material 1 is continuously formed. Then, the stretched glass base material 1 ′ that has passed through the take-off roller 5 in a cooled and solidified state is cut by a cutter 7 to obtain a plate-like or columnar spacer base 11 having a desired thickness (see FIG. 4). it can.
[0040]
Then, in the step of reducing the resistance of the spacer substrate by reducing the resistance, at least a part, and preferably all, of the surface glass material integrated with the two surfaces on the long side of the cross section of the core glass material 2 has a resistivity of 10%. ⁸ -10 ¹⁰ It is preferable to perform a reduction treatment until the resistance becomes Ω · cm. This level of resistivity is low enough to allow the surface layer of the spacer to properly discharge the charged charge from the contact portion between the spacer and other members, and excessive current flows between the substrates through the spacer. This is because the resistance is high enough not to flow.
[0041]
In order to perform such a reduction treatment, for example, when the surface glass material 3 is a glass material containing 40% by weight of PbO, the spacer base 11 is disposed in a reduction treatment apparatus as shown in FIG. When the atmosphere in the container is adjusted by setting the flow rate of hydrogen in the container to 0.5 to 2 l / min, the reduction treatment is preferably performed at a heating temperature of 450 to 550 ° C. for 1 to 2 hours.
[0042]
When the glass base material 1 is stretched, both the core glass material 2 and the surface glass material 3 have a viscosity of 10%. ⁵ -10 ¹⁰ It is preferable that the heating is performed at a stretching temperature within the range of dPa · s and at which the viscosity of the surface glass material 3 becomes higher than the viscosity of the core glass material 2. The viscosity of the core glass material 2 and the surface glass material 3 at the stretching temperature is 10 ⁵ -10 ¹⁰ If it is out of the range of dPa · s, it becomes difficult to stretch the glass base material 1. The specific stretching temperature varies depending on the material of the core glass material 2 and the surface glass material 3 and the like, but is generally about 500 to 1000 ° C.
[0043]
Both the core glass material 2 and the surface glass material 3 have a viscosity of 10 ⁵ -10 ¹⁰ Stretching by heating to a stretching temperature within the range of dPa · s and at which the viscosity of the surface glass material 3 becomes higher than the viscosity of the core glass material 2 is performed by the core glass material and the surface glass material in the present invention. Both surface glass materials have a viscosity of 10 ⁵ -10 ¹⁰ The heating can be performed by using glass materials in which the viscosity of the surface glass material is higher than the viscosity of the core glass material when heated to a temperature in the range of dPa · s. The adjustment of the viscosity of the core glass material 2 and the surface glass material 3 can be performed by adjusting the components of the core glass material 2 and the surface glass material 3 and the amounts of the components. For example, in an oxide glass, the viscosity in a high-temperature region can be reduced (increased) by increasing (decreasing) the content of the contained alkali oxide, boron oxide, lead oxide, and the like. By increasing (decreasing) the content of silicon oxide, aluminum oxide, titanium oxide, zirconium oxide, or the like, the viscosity in the high-temperature region can be increased (decreased). Further, the adjustment of the above components and the compounding amount thereof and the adjustment of the heating temperature of the core glass material 2 and the surface glass material 3 can be used together. The heating temperature is adjusted by, for example, irradiating infrared rays through a lens or a concave mirror focused on the center of the core glass material 2 so that the core glass material 2 is heated to a higher temperature than the surface glass material 3. It can be performed by heating. The difference in viscosity between the core glass material 2 and the surface glass material 3 at the stretching temperature is preferably 0.1 dPa · s or more in order to easily obtain the effect of suppressing swelling.
[0044]
According to the stretching method in consideration of the above viscosity, a spacer base without swelling and constriction can be obtained as shown in an enlarged manner in FIG. This is because the viscosity of the surface glass material 3 covering the two long sides of the cross section of the core glass material 2 is higher than the viscosity of the core glass material 2 at the above stretching temperature. It is considered that even if the viscosity of the core glass material 2 at both ends in the direction becomes too low, the surface glass material 3 covering the core glass material 2 can suppress swelling. Therefore, when the glass preform 1 is composed of the core glass material 2 alone, even if the glass base material 1 is heated to a stretching temperature that causes swelling at both ends in the cross-section longitudinal direction, the swelling does not occur, and neither swelling nor constriction occurs. By using the spacer base 11, a spacer without swelling and constriction can be obtained.
[0045]
Usually, the thickness of the spacer 8 (may be referred to as the thickness of the spacer base 11) is about 0.05 to 0.5 mm, and the thickness of the surface glass material 3 when the spacer 8 having such a thickness is 0.1 mm. It is preferably from 5 to 5 μm. That is, the thickness of the glass base material 1 and the thicknesses of the core glass material 2 and the surface glass material 3 in the glass base material 1 are preferably such that the thickness after stretching is within the above range. If the thickness of the surface glass material 3 in the glass base material 1 is too large, it is difficult to perform stretching, and if the thickness of the surface glass material 3 is too small, it is difficult to obtain the effect of suppressing swelling. Further, in order to make the surface glass material have an appropriate sheet resistance so as to function as an antistatic film, the surface glass material used as the spacer 8 preferably has the above-described thickness.
[0046]
Further, since the shape stability of the spacer is good, another effect can be obtained. This effect will be described with reference to FIGS. FIG. 13 is a conceptual cross-sectional view for explaining a state in which spacers are arranged so as to support between the substrates, and FIG. 14 is a conceptual view for explaining a step of forming a low-resistance film on a bonding surface of the spacer with the substrate. FIG. In FIG. 13, reference numeral 9 denotes a low-resistance film, 1000 denotes a substrate, and 1001 denotes a wiring disposed on the substrate. FIG. 13 shows a preferred embodiment described later in which a plurality of grooves are provided on the surface of the spacer.
[0047]
In order to prevent the spacer from being charged, as shown in FIG. 13, not only is an antistatic portion (surface glass material 3) formed on the surface of the spacer 8, but also the spacer 8 is used to efficiently discharge the electric charge to the outside. It is preferable to provide the low-resistance film 9 on the bonding surface with the substrate 1000 and the wiring 1001 arranged on the substrate.
[0048]
There are various methods for forming the low-resistance film 9. As a method for forming a high-quality low-resistance film 9 on a large number of spacers, a method as shown in FIG. 14 is considered. That is, a large number of spacers 8 are bundled in a state where the bonding surface with the substrate is exposed, and a low-resistance material such as a metal is deposited on the exposed portion by a sputtering method or the like.
[0049]
However, the shape stability is poor. For example, when spacers having a distorted shape as shown in FIGS. 15 and 16 are bundled, a gap is formed between the spacers. And the predetermined low resistance film 9 cannot be formed.
[0050]
If the spacer 8 is formed with good shape stability by the method according to the preferred embodiment of the present invention, such a problem at the time of forming the low-resistance film 9 can be avoided, and a good low-resistance film 9 can be obtained. Will be done.
[0051]
FIG. 5 is a partially enlarged view showing another example of the glass base material, and FIG. 6 is a perspective view showing a spacer base according to the present invention obtained from the glass base material of FIG. 5, and the same reference numerals as in FIGS. It is shown. Reference numeral 3 'denotes a surface glass material addressed to two surfaces on the short side of the cross section.
[0052]
In the glass base material 1 in this example, all surfaces on the long side and the short side of the cross section of the core glass material 2 are covered with the surface glass materials 3 and 3 '. By doing so, the spacer base 11 obtained has the short side of the cross section covered with the surface glass material 3 ′, and the smoothness of the short side of the cross section can be more easily obtained. Further, in this example, the surface glass material 3 on the long side of the cross section and the surface glass material 3 ′ on the short side of the cross section of the core glass material 2 are made of different types of glass materials having different types and / or different amounts of components. And swelling prevention control can be performed precisely.
[0053]
More preferably, in the step of reducing the resistance of the spacer base material by reducing treatment, at least a part, preferably all of the surface glass material integrated with the two surfaces on the short side of the cross section of the core glass material has a resistivity of at least one. , 10 ³ -10 ⁴ That is, a reduction treatment is performed until Ω · cm is reached. Here, the surface glass material 3 'addressed to the two surfaces on the short side of the cross section is made of a glass material containing 60% by weight or more of PbO, whereby the two surfaces on the long side of the cross section are integrated. At the same time as the reduction treatment for making the surface glass material a preferable resistivity, the surface glass material integrated on the two surfaces on the short side of the cross section can also have the above-mentioned preferable resistivity. Thus, the surface glass material integrated with the two surfaces on the short side of the cross section can be used as the low resistance film 9.
[0054]
Next, a method of forming another spacer base using the method shown in FIG. 2 will be described. In this embodiment, as shown in FIG. 7, the surface glass material constituting the glass base material has a plurality of grooves along the stretching direction on the outer surface side, that is, the surface opposite to the surface directed to the core glass material 2. (Surface glass material 3 ″).
[0055]
The shape of the groove provided in the surface glass material 3 ″ constituting the glass base material 1 may be rectangular, trapezoidal, semicircular, etc., as shown in JP-A-2000-31608. The angle of incidence of electrons incident on the surface of the spacer 8 in a state where the substrate 8 is disposed between the substrates may be determined as appropriate in accordance with a design that makes it possible to make the incident angle as small as possible. 11 shows a case where the cross section of the groove is trapezoidal as shown in Fig. 11. When the cross section of the groove is trapezoidal as shown in Fig. 11, the incidence of electrons incident on the spacer surface is reduced. This is preferable because the angle can be made smaller.
[0056]
The dimensions such as the width, depth, and pitch of the groove differ depending on how much stretching is performed, and this is also appropriately determined according to the design of the completed state. The grooves in the present invention are not necessarily provided continuously in the stretching direction of the glass base material, and may be interrupted on the way, but considering the ease of processing, grooves continuous in the stretching direction are considered. Is preferably provided.
[0057]
When the uneven structure is formed on the surface of the spacer in this manner, the angle of incidence of electrons incident on the surface of the spacer in a state where the spacer is disposed between the substrates can be made as small as possible, thereby preventing the spacer from being charged. Can be further improved.
[0058]
According to the manufacturing method of the present embodiment, when manufacturing a spacer having such a concavo-convex structure, grooves need only be formed on one surface of the surface glass material. Thus, the time can be shortened.
[0059]
As a method of using a member having a plurality of grooves along the stretching method on the outer surface side as a surface glass material, there is a form in which a groove is formed in a single plate-like member as described above, but it is configured from a plurality of thin plate members. The preferred embodiment is also a preferred embodiment. As the thin plate member for this purpose, a member having the same width as the pitch of the plurality of grooves and having two different thickness portions corresponding to the peaks and valleys of the grooves is used. FIG. 12 is a conceptual diagram for explaining an embodiment in which a surface glass material is constituted by such a plurality of thin plate members. In FIG. 12, 3 ′ ″ represents a thin plate member. As described above, in this embodiment, a plurality of thin plate members 3 ′ ″ having almost the same shape are prepared, thereby covering the surface on the long side of the cross section of the peripheral side surface of the core glass material 2 as shown in FIG. Constitutes part or all of the surface glass material.
[0060]
The shape of the thin plate member may be made in the form of one pitch in conformity with the grooves having various shapes as described above formed on the surface glass material.
[0061]
According to the configuration in which the surface glass material is constituted by a plurality of such thin plate members, the production of a single-shaped member can be simplified more than the provision of a groove in the plate material, thereby further reducing the production. Costs can be reduced.
[0062]
In this embodiment using a surface glass material having a plurality of grooves, for the same reason as above, in the step of reducing the resistance, the surface glass integrated with the two surfaces on the longer side of the cross section of the core glass material. The resistivity of at least a part of the material is 10 ⁸ -10 ¹⁰ Reduction treatment to Ω · cm, using a glass base material whose surface glass material is further addressed to two surfaces on the short side of the cross section of the core glass material, two surfaces on the short side of the cross section of the core glass material Is made of a glass material containing 60% by weight or more of PbO, and the surface glass material integrated with the two surfaces on the short side of the cross section of the core glass material in the step of lowering the resistance. Has a resistivity of at least 10 ³ -10 ⁴ Needless to say, the reduction treatment is preferably performed until Ω · cm is reached.
[0063]
In all the embodiments in which the glass base material is formed of the core glass material and the surface glass material, in the step of forming the spacer base, the glass base material is set to have a viscosity of 10% for both the core glass material and the surface glass material. ⁵ -10 ¹⁰ It is preferable to heat and stretch at a stretching temperature within the range of dPa · s and at which the viscosity of the surface glass material is higher than the viscosity of the core glass material, for the same reason as described above.
[0064]
【Example】
(Example 1)
The spacer base 11 was formed by stretching the heated glass base material 1 using the mechanical chuck 4 and the take-off roller 5 as shown in FIG.
[0065]
As the glass base material 1, a surface glass material 3 having a thickness of 1 mm and a width of 48 mm is formed on the surface on the long side of the cross section of a core glass material 2 having a rectangular shape having a cross section of 4 mm × 48 mm in the form shown in FIG. And the total cross-sectional area S ₁ Is 288mm ² (6 mm x 48 mm) was used. As a material, the core glass material 2 has a viscosity of 10 at a heating temperature of 700 ° C. during stretching. ⁶ dPa · s, the surface glass material 3 has a PbO content of 40% by weight, and a viscosity of 10 at a heating temperature of 700 ° C. during stretching. ^7.6 dPa · s was used.
[0066]
The above glass preform 1 is ₁ = 5 mm / min, and sent out by lowering the mechanical chuck 4, heated to about 700 ° C. by the heater 6, and V-pressed by the take-up roller 5 arranged near the heater 6. ₂ = 4500 mm / min, the film was heated and stretched, and finally cut with a cutter 7 to a length of 1000 mm. The cross-sectional area S of the obtained spacer 8 ₂ Is 0.32 (0.2 × 1.6 mm) mm ² No partial necking and bulging described above were observed.
[0067]
Next, the surface of the spacer substrate 11 was reduced with hydrogen using the hydrogen reduction apparatus shown in FIG. 1 to reduce the resistance, thereby producing a spacer. Specifically, the surface glass material is obtained by disposing the spacer base 11 in the container 31 of the apparatus of FIG. 1 and performing a reduction treatment at a hydrogen flow rate of 1 l / min and a heating temperature of 500 ° C. for 1 hour in the container. Sheet resistance of part 3 is 10 ¹⁴ Ω / □ spacers were obtained.
[0068]
(Example 2)
In this example, a spacer was prepared in the same manner as in Example 1 except that the PbO content of the surface glass material 3 was changed to 50% by weight. In the spacer prepared in this example, no partial necking and swelling were observed as in Example 1, and the sheet resistance of the surface glass material 3 was 10%. ¹² Ω / □ spacers were obtained.
[0069]
(Comparative Example 1)
In this example, a spacer was prepared in the same manner as in Example 1 except that the PbO content of the surface glass material 3 was changed to 30% by weight. In the spacer prepared in this example, no partial necking and swelling were observed as in Example 1, but the sheet resistance of the surface glass material 3 was 10%. ¹⁶ Ω / □.
[0070]
For this reason, hydrogen reduction was further performed for 1 hour under the same conditions, ^15.5 Ω / □, and sufficient conductivity could not be obtained.
[0071]
(Comparative Example 2)
In this example, a spacer was prepared in the same manner as in Example 1 except that the PbO content of the surface glass material 3 was changed to 20% by weight. In the spacer prepared in this example, no partial necking and swelling were observed as in Example 1, but the sheet resistance of the surface glass material 3 was 10%. ^17.5 Ω / □.
[0072]
For this reason, hydrogen reduction was further performed for 1 hour under the same conditions, ¹⁷ Ω / □, and sufficient conductivity could not be obtained.
[0073]
(Example 3)
In this example, a spacer was produced in the same manner as in Example 1 except that a groove having a rectangular cross section was formed on the surface of a surface glass material as shown in FIG. The depth of the groove of the surface glass material 3 ″ was 0.3 mm, the width was 0.3 mm, and the pitch was 0.9 mm.
[0074]
As a result, a high-quality spacer was obtained as in Example 1, and the sheet resistance of the surface glass material 3 ″ was finally 10 ¹⁴ Ω / □. The groove of the obtained spacer had a rectangular cross section, a depth of 10 μm, a width of 10 μm, and a pitch of 30 μm.
[0075]
(Example 4)
The spacer of this embodiment is the same as that of the third embodiment except that the grooves of the surface glass material of the third embodiment are formed by arranging a plurality of thin plate members 3 ′ ″ as shown in FIG. Created similarly.
[0076]
The dimension of one thin plate member 3 ′ ″ has an overall width of 0.9 mm, of which the width of the maximum thickness portion is 0.6 mm and the width of the minimum thickness portion is 0.3 mm, The maximum thickness was 1 mm and the minimum thickness was 0.7 mm.
[0077]
In this example, the same high-quality spacer as in Example 3 was obtained.
[0078]
(Example 5)
The spacer base 11 was formed by stretching the heated glass base material 1 using the mechanical chuck 4 and the take-off roller 5 as shown in FIG.
[0079]
As the glass base material 1, in the form shown in FIG. 5, a surface glass material 3 having a thickness of 1 mm and a width of 46 mm is provided on a surface on the longer side of the cross section of a core glass material 2 having a rectangular cross section of 4 mm × 46 mm. The surface glass material 3 ′ having a thickness of 1 mm and a width of 6 mm is directed to the surface on the short side of the cross section of the core glass material 2. ₁ Is 288mm ² (6 mm x 48 mm) was used. As a material, the core glass material 2 has a viscosity of 10 at a heating temperature of 700 ° C. during stretching. ^6.0 The surface glass materials 3 and 3 ′ have a PbO content of 40% by weight and a viscosity at a heating temperature of 700 ° C. of 10 when stretched. ^7.6 dPa · s was used.
[0080]
The above glass preform 1 is ₁ = 5 mm / min, and sent out by lowering the mechanical chuck 4, heated to about 700 ° C. by the heater 6, and V-pressed by the take-up roller 5 arranged near the heater 6. ₂ = 4500 mm / min, the film was heated and stretched, and finally cut with a cutter 7 to a length of 1000 mm. The cross-sectional area S of the obtained spacer 8 ₂ Is 0.32 (0.2 × 1.6 mm) mm ² The above-mentioned partial necking and bulging were not observed, and the flatness on the short side of the cross section was particularly superior to the spacer of Example 1.
[0081]
Next, the surface of the spacer substrate 11 was reduced with hydrogen using the hydrogen reduction apparatus shown in FIG. 1 to reduce the resistance, thereby producing a spacer. Specifically, the surface glass material is obtained by disposing the spacer base 11 in the container 31 of the apparatus of FIG. 1 and performing a reduction treatment at a hydrogen flow rate of 1 l / min and a heating temperature of 500 ° C. for 1 hour in the container. The sheet resistance of the portion 3 or 3 'is 10 ⁴ Ω / □ spacers were obtained.
[0082]
(Example 6)
In this example, a spacer was produced in the same manner as in Example 5, except that a groove having a rectangular cross section was formed on the surface of the surface glass material as shown in FIG. The depth of the groove of the surface glass material 3 ″ was 0.3 mm, the width was 0.3 mm, and the pitch was 0.9 mm.
[0083]
As a result, a good quality spacer was obtained as in Example 5, and the sheet resistance of the surface glass material 3 ′, 3 ″ was finally 10 ⁴ Ω / □. The groove of the obtained spacer had a rectangular cross section, a depth of 10 μm, a width of 10 μm, and a pitch of 30 μm.
[0084]
(Example 7)
The spacer of this embodiment is the same as that of the sixth embodiment except that the grooves of the surface glass material in the sixth embodiment are formed by arranging a plurality of thin plate members 3 ′ ″ as shown in FIG. Created similarly.
[0085]
The dimension of one thin plate member 3 ′ ″ has an overall width of 0.9 mm, of which the width of the maximum thickness portion is 0.6 mm and the width of the minimum thickness portion is 0.3 mm, The maximum thickness was 1 mm and the minimum thickness was 0.7 mm.
[0086]
Also in this example, the same good-quality spacer as in Example 6 was obtained.
[0087]
(Example 8)
In this example, a 10 nm-thick Ti film and a 200 nm-thick Pt film are formed by sputtering on the spacers manufactured in Examples 1 to 7 in this order by the method described with reference to FIG. It is.
[0088]
As a result, no wraparound of the film-forming material was observed on the side surface on the longer side of the cross section of the spacer, and the sheet resistance was 10%. ³ A desired low resistance film of Ω / □ was obtained.
[0089]
(Example 9)
In this example, the material of the surface glass material 3 ′ addressed to the surface on the short side of the cross section of the core glass material 2 was prepared by adding a PbO content of 60% by weight and a viscosity of 10 ° C. at a heating temperature of 700 ° C. during stretching. ^7.6 A spacer was prepared in the same manner as in Example 5 except that dPa · s was used.
[0090]
In the spacer obtained in this example, the portion of the surface glass material 3 ′ has a sheet resistance of 10 ³ Ω / □, which was sufficient to function as a low resistance film.
[0091]
【The invention's effect】
As described above, according to the present invention, it is possible to form a portion having a relatively low electric resistance for antistatic at a surface layer portion of a spacer with good controllability, and a simpler method of manufacturing a spacer. A spacer can be provided.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram for explaining an example of a method for reducing a spacer substrate according to the present invention.
FIG. 2 is an explanatory view showing an example of a method of manufacturing a spacer base according to the present invention.
FIG. 3 is a partially enlarged view of the glass base material shown in FIG. 2;
FIG. 4 is a perspective view showing a spacer base according to the present invention obtained by the method of FIG. 2;
FIG. 5 is a partially enlarged view showing another example of the glass base material.
FIG. 6 is a perspective view showing a spacer base in the present invention obtained from the glass base material of FIG.
FIG. 7 is a partially enlarged view showing another example of the glass base material.
8 is a perspective view showing a spacer base according to the present invention obtained from the glass base material of FIG. 7;
FIG. 9 is a partially enlarged view showing another example of the glass base material.
FIG. 10 is a perspective view showing a spacer base in the present invention obtained from the glass base material of FIG.
FIG. 11 is a cross-sectional view of a glass base material in which a cross section of a groove provided in a surface glass material is trapezoidal.
FIG. 12 is a conceptual diagram of a glass base material for explaining an embodiment in which a surface glass material is constituted by a plurality of thin plate members.
FIG. 13 is a conceptual cross-sectional view for explaining a state in which spacers are arranged to support between substrates.
FIG. 14 is a conceptual diagram for explaining a step of forming a low-resistance film on a bonding surface of a spacer with a substrate.
FIG. 15 is an explanatory diagram of a state of occurrence of constriction.
FIG. 16 is an explanatory diagram of a state in which bulging occurs.
[Explanation of symbols]
1 Glass base material
1 'stretched glass base material
2 Core glass material
3,3 ', 3 ", 1003 Surface glass material
3 '''thin plate member
4 Mechanical chuck
5 Pickup roller
6 heater
7 cutter
8 Spacer
9 Low resistance film
11 Spacer substrate
31 containers
32 heater
33 Reflector
1000 substrates
1001 Wiring

Claims (28)

Forming a spacer substrate made of a glass material containing at least a part of the surface layer portion containing 40% by weight or more of PbO;
A step of reducing the resistance of at least a part of the surface layer portion by reducing the spacer substrate,
A method for producing a spacer, comprising: In the step of forming the spacer base, a glass base material using a glass material containing 40% by weight or more of PbO in at least a part of the surface layer portion is heated and stretched, and the stretched stretched glass base material is stretched to a required length. The method for producing a spacer according to claim 1, wherein the spacer substrate is formed by cutting into pieces. The glass base material has a cross-sectional shape with different vertical and horizontal dimensions,
A composite comprising the glass base material, a core glass material disposed in an inner layer of the glass base material, and a surface glass material disposed in a region including an outer surface along at least a cross-sectional longitudinal direction of a surface layer portion of the glass base material. Structure and
The method for manufacturing a spacer according to claim 2, wherein the surface glass material is made of a glass material containing 40% by weight or more of PbO. The spacer according to claim 3, wherein the core glass material has a rectangular cross-sectional shape, and the surface glass material is a glass base material addressed to at least two surfaces on the longer side of the cross-section of the core glass material. Method. In the step of reducing the resistance, the reduction treatment is performed until the resistivity of at least a part of the surface glass material integrated on the two surfaces on the longer side of the cross section of the core glass material becomes 10 ⁸ to 10 ¹⁰ Ω · cm. The method for producing a spacer according to claim 4, wherein: The method for manufacturing a spacer according to claim 4, wherein the surface glass material further uses a glass base material addressed to two surfaces on the short side of the cross section of the core glass material. The method for manufacturing a spacer according to claim 6, wherein the surface glass material addressed to the two surfaces on the short side of the cross section of the core glass material is made of a glass material containing 60% by weight or more of PbO. In the step of reducing the resistance, the reduction treatment is performed until the resistivity of at least a part of the surface glass material integrated with the two surfaces on the short side of the cross section of the core glass material becomes 10 ³ to 10 ⁴ Ω · cm. The method for producing a spacer according to claim 6, wherein: The method for manufacturing a spacer according to claim 3, wherein the surface glass material uses a glass base material including a member having a plurality of grooves on an outer surface side along a stretching direction. The cross-sectional shape of the core glass material is rectangular, and the surface glass material having a plurality of grooves along the stretching direction on the outer surface side uses a glass base material addressed to two surfaces on the longer side of the cross-section of the core glass material. The method for producing a spacer according to claim 9, wherein: The surface glass material addressed to the two surfaces on the longer side of the cross section of the core glass material includes a plurality of thin plate members, the thin plate members having the same width as the pitch of the plurality of grooves, The method for manufacturing a spacer according to claim 10, wherein the spacer has two portions having different thicknesses corresponding to the portions and the valleys. In the step of reducing the resistance, the reduction treatment is performed until the resistivity of at least a part of the surface glass material integrated on the two surfaces on the longer side of the cross section of the core glass material becomes 10 ⁸ to 10 ¹⁰ Ω · cm. The method for producing a spacer according to claim 10, wherein: The method for manufacturing a spacer according to any one of claims 10 to 12, wherein the surface glass material further uses a glass base material directed to two surfaces on the short side of the cross section of the core glass material. 14. The method for manufacturing a spacer according to claim 13, wherein the surface glass material addressed to the two surfaces on the shorter side of the cross section of the core glass material is made of a glass material containing 60% by weight or more of PbO. In the step of reducing the resistance, the reduction treatment is performed until the resistivity of at least a part of the surface glass material integrated with the two surfaces on the short side of the cross section of the core glass material becomes 10 ³ to 10 ⁴ Ω · cm. The method for manufacturing a spacer according to claim 14, wherein: In the step of forming the spacer base, the glass base material is adjusted such that the viscosity of the core glass material and the surface glass material are both within the range of 10 ⁵ to 10 ¹⁰ dPa · s, and the viscosity of the surface glass material is higher than the viscosity of the core glass material. The method for producing a spacer according to any one of claims 3 to 15, wherein the film is stretched by heating to a higher stretching temperature. A spacer having at least a part of a surface layer part having a resistance reduced by reducing a glass material containing PbO. The spacer has a composite structure in which a core glass material disposed in an inner layer of the spacer and a surface glass material disposed in a region including an outer surface along at least a cross-sectional longitudinal direction in a surface layer portion of the spacer are integrated. A spacer having at least a portion of a surface glass material having a resistance reduced by reducing a glass material containing PbO. The cross-sectional shape of the core glass material is rectangular, and the surface glass material is integrated with at least two surfaces on the long side of the cross section of the core glass material. 19. The spacer according to claim 18, wherein at least a part of the spacer has a portion whose resistance is reduced by reducing a glass material containing PbO. 20. The resistivity of the low-resistance portion of the surface glass material integrated on the two long sides of the cross section of the core glass material is 10 ⁸ to 10 ¹⁰ Ω · cm. The spacer as described. The surface glass material is further integrated on two surfaces on the short side of the cross section of the core glass material, and at least a part of the surface glass material integrated on the two surfaces on the short side of the cross section contains a glass material containing PbO. The spacer according to claim 19, wherein the spacer has a portion whose resistance is reduced by a reduction treatment. 22. The method according to claim 21, wherein the resistivity of the low-resistance portion of the surface glass material integrated with the two surfaces on the short side of the cross section of the core glass material is 10 ³ to 10 ⁴ Ω · cm. The spacer as described. 19. The spacer according to claim 18, wherein the surface glass material includes a portion having a plurality of grooves on the outer surface side along the stretching direction. The cross-sectional shape of the core glass material is rectangular, and the surface glass material having a plurality of grooves on the outer surface along the stretching direction is integrated with the two surfaces on the cross-sectional long side of the core glass material, 24. The spacer according to claim 23, wherein at least a part of the surface glass material integrated on two surfaces has a portion whose resistance is reduced by reducing a glass material containing PbO. 25. The resistivity of the low-resistance portion of the surface glass material integrated on the two surfaces on the longer side of the cross section of the core glass material is 10 ⁸ to 10 ¹⁰ Ω · cm. The spacer as described. The surface glass material is further integrated on two surfaces on the short side of the cross section of the core glass material, and at least a part of the surface glass material integrated on the two surfaces on the short side of the cross section contains a glass material containing PbO. The spacer according to claim 24 or 25, wherein the spacer has a portion whose resistance is reduced by a reduction treatment. The resistivity of the low-resistance portion of the surface glass material integrated with the two surfaces on the short side of the cross section of the core glass material is 10 ³ to 10 ⁴ Ω · cm. The spacer as described. When the core glass material and the surface glass material are heated to a temperature at which both the viscosity of the core glass material and the surface glass material fall within the range of 10 ⁵ to 10 ¹⁰ dPa · s, the viscosity of the surface glass material is The spacer according to any one of claims 18 to 27, wherein the spacer is a glass material having a high viscosity.

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