JPS63139021A - Production of very thin flat sheet glass - Google Patents

Abstract

PURPOSE:To obtain very thin flat sheet glass without causing microcracking, strain or devitrification by producing a glass sheet having a desired thickness, heating it to a temp. just below the melting temp., melting only the surface of the sheet and solidifying it. CONSTITUTION:A glass block having a prescribed compsn. is mechanically sliced to produce a first glass sheet having a desired thickness or a thickness made as close as possible to the desired thickness in case where the desired thickness can not be attained. When the thickness of the first glass sheet is larger than the desired thickness, the surface of the sheet is etched to produce a second glass sheet having the desired thickness. The first or second glass sheet is entirely preheated to a temp. just below the melting temp. and a prescribed quantity of heat energy is radiated on the surface of the sheet in a short time to melt only the surface of the sheet. The molten surface is then solidified and the desired glass is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a completely new method for manufacturing ultra-thin flat glass, and in particular, to a sheet type electrode for measuring various ion concentrations such as pH and pNa. This was done with the aim of developing a method for obtaining a flat glass responsive membrane (ion-responsive ultra-thin flat glass), which is absolutely necessary in cases where the invention is intended to be used.

[Conventional technology]

Conventional ion concentration measuring electrodes such as pH measuring electrodes (
As shown in Figure 6, the so-called glass electrode) is a hemispherical glass-responsive membrane (ion-responsive electrode) that is formed by blowing up a fire-making method (balloon method) at the tip of a support tube a made of electrically insulating glass. It is constructed by bonding an extremely thin glass film (b) and enclosing an internal electrode C and an internal liquid d therein. In this case, since the ion-responsive ultra-thin glass film is formed by the blow-up method (balloon method) as described above, the heating temperature is adjusted to control the film thickness during processing. Adjusting the amount of blowing, etc., or preventing the occurrence of micro-crank when joining it to the support tube a requires considerable skill, and since mass production is difficult, the manufacturing cost is not only high, but also Although the overall structure has to be large and there are many disadvantages in terms of operability and maintainability, it still has the required membrane H (0.1 to 0.3 mm). i t7 responsiveness i
It was possible to realize a 1 glass film b (however, hemispherical).

On the other hand, recently, for example, the applicant's patent application
As proposed in No. 1-63564, etc., the development of a technology to gel the internal liquid eliminates the need for a glass responsive membrane, as in the case of salinity measuring electrodes, reference electrodes, or their combination electrodes. As shown in Figures 7(a) and 7(b), it is now possible to form a sheet into a sheet, thereby achieving a smaller overall structure, lower manufacturing costs, and improved operability and maintainability. It has reached this point.

In the composite electrode for salinity measurement shown in FIGS. 7(a) and 7(b), e is a substrate made of vinyl chloride, etc., and a plurality of (four in this example) silver electrodes are mounted on the top surface of the substrate. f・
... are formed by screen printing or the like, and each base end thereof is formed as a lead part g..., and each tip end thereof is coated with a film of silver chloride, an internal electrode part h... A support layer i made of vinyl chloride or the like is formed by screen printing or the like on the substrate e excluding the portion where the internal electrode portions h... are present. And j...
・Respectively, gelling agents (e.g. agar, gelatin, etc.) and gel evaporation inhibitors (e.g. glycerin, ethylene glycol, etc.) are added to the basic internal liquid (e.g. 3.3NKG1 supersaturated with AgC1). A gel-like internal liquid made into a paste by heating is applied by screen printing or the like to be superimposed on each of the internal electrode parts h. In addition, k, k, m, and m are a response membrane made of, for example, an organic material and a liquid junction made of a porous body impregnated with K (1! The membrane is fixed to the support layer i by an adhesive or the like around the membrane.Furthermore, n is a recess for injecting the test liquid formed on the surface side of the support layer i, and 0 is the recess for injecting the test liquid. A lid body that can be opened and closed for a test liquid injection recess n, one edge of which is fixed to the upper surface of the support layer i, and p is an adhesive layer provided on the upper surface of the support layer i. By tightly and tightly contacting the lid body 0 to this adhesive layer p, the recess n for injecting the test liquid can be brought into a sealed state. After opening the lid 0 and injecting about one drop of the test liquid into the recess n, the lid 0 is closed and the test liquid is applied to each of the response membranes k and junction membranes m and m. After pushing upward and spreading, the lid body 0 is closely fixed to the adhesive layer p,
Thereafter, this sheet-type composite electrode for salinity measurement is inserted and connected to the attachment part of a measuring device body (not shown) configured in the shape of a card calculator, for example, at the lead part g. It measures the salinity of liquid.

Therefore, along with the realization of sheets for salinity measuring electrodes, reference electrodes, and their composite electrodes, it is natural that ion concentration measuring electrodes such as pH measuring electrodes will also be made into sheets, which will reduce the overall structure and reduce manufacturing costs. There is a strong demand for lower costs and improvements in operability and maintainability, but at present, flat plate-like materials that require a film thickness close to the vitrification limit (o, 1 to 0.3 mm) Since it is impossible to manufacture a glass responsive membrane (ion-responsive ultra-thin glass membrane), it has not yet been realized.

That is, conventionally, thin glass sheets with a thickness of at least about 1 mm are produced by the vertical pulling method, and thinner glass sheets (for example, those used for preparations, etc.) are produced using the vertical pulling method as much as possible. It was manufactured by further polishing thin plate glass. However, in that case, the manufacturing cost is extremely high and relatively large irregularities and microcranks remain on the glass surface, so it cannot be used as a glass response membrane for ion concentration measurement electrodes. For example, on a glass surface with large irregularities and microcracks, the test liquid cannot be adsorbed and desorbed smoothly, making accurate measurements impossible.

In addition, methods for producing ultra-thin flat glass include cutting off part of the circumference of ultra-thin hemispherical glass formed by the balloon method and then reshaping it into flat glass using a hot plate press, or softening pre-formed glass. A preform annulation method in which the glass is stretched by elevating the temperature above that temperature has been known for some time, but in the case of the former glass remolding method, it is difficult to obtain ultrathin flat glass of sufficient size. However, the disadvantage is that microcranks are likely to occur on the glass surface, and the latter preform annulation method requires extremely large-scale equipment and tends to leave distortions in the finished ultra-thin flat glass. There is a drawback.

Moreover, in both of the above methods, ordinary glass (such as so-called sodium glass) whose temperature-viscosity curve exhibits a relatively gentle slope and whose composition allows a relatively wide temperature range for molding operation is used. This method is effective only in cases where the temperature-viscosity curve exhibits a relatively steep slope, such as with special glass (so-called lithium glass) used as a glass response membrane for ion concentration measurement electrodes. , when applied to a material whose composition has a narrow temperature range for molding operation, crystallization of the glass (loss of i3) will occur.
It is simply impossible to obtain the desired ultra-thin flat glass.

[Problem that the invention seeks to solve]

The present invention has been made in view of the above-mentioned conventional situation, and its purpose is to prevent microcracks, distortion, crystallization (
The objective of the present invention is to develop and provide a completely new method for producing ultra-thin flat glass at a relatively low cost and without causing devitrification.

[Means for solving problems]

In order to achieve the above object, ff1F! according to the present invention! The manufacturing method of flat glass consists of slicing a glass block manufactured to have a predetermined composition by mechanical cutting means to a target thickness or, if this is not possible, as much as possible to the target thickness. A first glass sheet with a thickness close to the target thickness is manufactured, and if the first glass sheet is thicker than the target thickness, the surface of the first glass sheet is further etched to achieve the target thickness. A second glass sheet is manufactured, and then, in a state where the entire first or second glass sheet is preheated and raised to just before the melting temperature, a further portion is added to the surface of the first or second glass sheet. It is characterized in that it employs a procedure in which only the surface of the first or second glass sheet is melted and then solidified by applying a fixed amount of thermal energy in a short period of time.

[Effect]

The effects achieved by employing such distinctive means are as follows.

That is, according to the method for manufacturing ultra-thin flat glass according to the present invention, as will become clearer from the description of the examples described later, first, a glass block (
It is easy to manufacture, does not cause crystallization or devitrification, and ensures good uniformity of composition), and then the glass block is sliced by mechanical cutting means. Then, a first glass sheet with a target thickness or, if that is not possible, a thickness as close to the target thickness as possible is manufactured. Regardless, even if known methods that are relatively easy to implement, such as the wire cutting method, inner peripheral blade cutting method, and outer peripheral blade cutting method, are used, it is not possible to obtain slices with a minimum thickness of around 0.08 mm. In terms of thinness, it is possible to easily obtain results that are comparable to conventional glass remolding methods and preform annulation methods. Or you can easily get one without a micro crank. However, since the surface of the first glass sheet still has unevenness due to mechanical cutting, it remains opaque (like ground glass) as it is,
Moreover, it cannot be in a completed state that can be used as a glass response membrane for an ion concentration measuring electrode, for example.

Note that if necessary, if the surface of the first glass sheet is further etched, a second glass sheet that is thinner and has surface irregularities reduced to some extent can be obtained, but it is still translucent. It will not be completed if it is in this state.

Therefore, it is necessary to process the first glass sheet or the second glass sheet to eliminate any remaining unevenness on the surface and make it transparent and have a sufficiently smooth surface. This was achieved using a heat treatment method that was previously considered impossible.

In other words, although cutting glass or processing the surface of glass using laser heat rays has been conceptually envisioned for some time, when it is actually carried out, there are drastic changes. Temperature changes or extremely uneven temperature distribution can cause the glass to break, or if the target glass is thin or tiny, it can melt and shrink, making it extremely difficult to do so. Proven.

The present invention solves these difficult obstacles by treating glass,
That is, the entire first or second glass sheet is prepared in advance by
This problem was overcome by raising the temperature to just before the melting temperature, and then applying a predetermined amount of thermal energy to the surface in a short period of time when it is on the verge of melting.

By employing such preheating and subsequent high-speed heat treatment means, only the surface of the first or second glass sheet can be melted and then solidified (recycled vitrification). It has sufficient thickness and size, has no microcracks or distortion, and has no microcracks or distortion, which could not be achieved by other methods.
It is now possible to easily and inexpensively produce ultra-thin flat glass that does not cause crystallization (devitrification) and has a sufficiently smooth and transparent surface, regardless of its composition. Ta.

Therefore, according to the method of the present invention, it is possible to produce a flat plate, which is absolutely necessary but could not be produced in the past, especially when constructing a sheet type 111i for measuring various ion concentrations such as pH and pNa. It has become possible to create a glass-responsive membrane (ion-responsive ultra-thin flat glass) and to use it to create a sheet-type ion measurement electrode.

Furthermore, the method of the present invention has extremely high utility value in the electronics field, such as IC substrates and phototransistor window members, where miniaturization is expected to progress further in the future, and in other optical fields.

〔Example〕

Hereinafter, a specific example of the method for manufacturing +4 thin flat glass according to the present invention will be described based on the drawings (FIGS. 1 to 5).

Here, the pH glass response membrane required to construct a sheet-type pH measurement electrode is length x width x thickness = 10 m.
An example of manufacturing an ultra-thin flat glass of mX 8n+n+X O, 1ffi+1 will be described.

Now, the manufacturing procedure of the ultra-thin flat glass as the pH glass responsive membrane is as follows.

First, a large glass ingot of pH glass having a predetermined composition is produced by mixing predetermined components and amounts of powder raw materials, melting and solidifying the mixture in a platinum crucible, etc., and then performing an annealing treatment. As a result, in this example, length x width x thickness = 328mm + X 93mm x 23m
A large glass ingot of m was obtained.

Producing large glass ingots in this manner not only allows considerable cost reduction, but also has the advantage of ensuring quality stability and composition uniformity.

Next, the large glass ingon is cut into a suitable shape using a mechanical cutting method (for example, there are known methods that can be carried out relatively easily, such as a wire cutting method, an inner peripheral cutting method, and an outer peripheral cutting method). Divide into sized glass blocks. As a result, in this example, length x width x thickness = 45mm x 45
Fourteen glass blocks of mm×23+nm were obtained.

Subsequently, each glass block is sliced using the same mechanical cutting means to obtain a target thickness of 0. 1
A first glass sheet with a thickness as close as possible (0.2 mm) to 0.2 mm is manufactured. As a result, in this example, length x width x thickness = 45 mm x 45 ms + X 0, 2
A large number of first glass sheets of mm in diameter were obtained.

Therefore, each of the first glass sheets still has a target thickness of 0.
．． It has a thickness (0.2 mm) greater than 1 mm), and has relatively large irregularities remaining on its surface due to the mechanical cutting, so it is in an opaque (ground glass-like) state.

Therefore, each of the first glass sheets is treated with, for example, 5% NH,
By immersing it in an F aqueous solution or the like, and etching the surface (both front and back sides) by a predetermined thickness (in this example, 0.05 mm), the target thickness is 0.5 mm. 1+mm) and whose surface irregularities have been reduced to some extent. Although it is possible to obtain a second glass sheet that is thinner and has surface irregularities reduced to some extent by this etching process, it is still in a translucent state and is not in a completed state. As a result, in this example, a second glass sheet of 1 mm in diameter was obtained.

In addition, when cutting to the final target thickness by the mechanical cutting means, only by the mechanical cutting means,
Since the first glass sheet with the target thickness is obtained, the manufacturing process of the second glass sheet by this etching process is as follows:
Not necessarily necessary.

Next, each of the second glass sheets is cut into chips having a predetermined size by a mechanical cutting means (such as dicing using a scriber).

As a result, in this example, the length x width x thickness - 10mm x 81*ll1x O, 1m, which has the desired size and thickness.
A chip-shaped second glass sheet of m was obtained.

Note that this chip-shaped second glass sheet is thoroughly cleaned, for example, by ultrasonic cleaning or the like, in order to remove wax, fluorine, etc.

Now, each of the chip-shaped second glass sheets obtained as described above needs to be transparent and have a sufficiently smooth surface by eliminating any remaining unevenness on its surface. Surface treatment is performed by novel heat treatment means.

In other words, the chip-like structure is designed to effectively prevent glass cracking and melting and condensation caused by sudden temperature changes or extremely uneven temperature distribution, which have traditionally been very difficult problems during glass heat treatment. 2. The entire glass sheet is heated in advance to just before the melting temperature, and in the preheated state on the verge of melting, a predetermined amount of thermal energy is further applied to the surface in a short period of time to melt only the surface. The team used a high-speed surface heating process to preheat the material, allowing it to dry and then solidify.

As a result, it has a sufficient size, no microcrank, no distortion, no crystallization (loss of i3), and has a sufficiently smooth and transparent surface, which could not be achieved by any conventional method. Fulfilling the strict condition that there is
It has now been possible to easily and inexpensively produce ultrathin flat glass that can be used satisfactorily as a pH glass responsive membrane, regardless of its composition.

By the way, various methods can be considered as specific implementation means for the above-mentioned preheating and high-speed surface heating treatment, but according to the prototype experiments to date, the following three methods are the most suitable.

One of them (first embodiment) is a so-called preheating laser heat irradiation method, and as shown in FIG. a temperature regulator 3 for the block 2;
A laser irradiation device 4 capable of irradiating, for example, a CO□ laser R (RW or IOW is sufficient) to a fixed point on the XY table 1, and the XY table 1. Temperature controller 3. A system comprising a controller 5 for controlling the laser irradiation device 4 and the like, and
Chip-shaped second glass sheet S obtained as described above
112z on the heater block 2, first,
The temperature regulator 3 for the heater block 2 is controlled by the controller 5, and the entire chip-shaped second glass sheet S is heated in advance to just before the melting temperature (in this example, it is about 600° C. below the softening point). , and then, in the preheated state on the verge of melting, the XY table 1 and the laser irradiation device 4 are controlled by the controller 5 to heat the chip-shaped second glass sheet (S) on the heater block 2 at a desired location or surface. By irradiating the entire surface with a CO2 laser R by scanning at a predetermined speed (in this example, it was about several cm and 7 seconds) and applying a predetermined amount of thermal energy in a short time, only the surface is melted. After preheating, high-speed surface heating treatment is performed to solidify the material. Furthermore, - lastly, when light is irradiated onto glass, heat absorption occurs first at its interface (surface), so the COt laser R is irradiated from one side of the chip-shaped second glass sheet S as described above. You can process both the front and back sides at the same time. In addition, this preheating laser heat irradiation method uses the chip-shaped second glass sheet S
This is particularly suitable when it is sufficient to precisely vitrify only a part (required part) of the surface.

The other one (second embodiment) is a so-called preheating lamp heat irradiation method, and as shown in FIG. A working board (e.g., carbon plate) 7 made of a material with excellent properties, thermal conductivity, and heat dissipation, and preferably black in color, and a lamp light (e.g., halogen lamp light) L can be focused onto the working board 7. and its luminous output and light concentration.

A lamp light irradiation device 8 that can adjust the irradiation time etc. and obtain sufficient light emission output (can achieve a maximum temperature of several thousand degrees Celsius in the condensing part), and a controller 9 for controlling the lamp light irradiation device 8. The chip-shaped second glass sheet S obtained as described above is placed on the working board 7, and the lamp light irradiation device 8 is controlled by the controller 5. First, the chip-shaped second glass sheet S is irradiated with lamp light while gradually increasing the light emitting output, with the light condensed to the same size or slightly thicker than the chip-shaped second glass sheet S. The entire second glass sheet S is heated in advance slowly to just before the melting temperature (in this example, it was about 600°C, which is below the softening point), and then continued in the preheated state on the verge of melting to a relatively high temperature. A chip-shaped second
By irradiating the entire surface of the glass sheet S for a short time (about a few seconds in this example) and applying a predetermined amount of thermal energy, only that surface is melted uniformly and then solidified. High-speed surface heating treatment is performed on the preheating. In this case as well, by simply irradiating lamp light from one side of the chip-shaped second glass sheet S, both the front and back sides can be treated simultaneously. In addition, this preheating lamp heat irradiation method is particularly suitable for precision vitrification of the entire surface of the chip-shaped second glass sheet S, but it may be necessary to narrow down the light concentration during surface treatment after preheating, or
By performing scanning irradiation in this state, similar to the preheating lamp heat irradiation method described above, precision vitrification of only a part (required location) of the surface of the chip-shaped second glass sheet S can be performed with relatively low energy consumption. It is also possible to realize this by

Still another one (third embodiment) is a so-called belt moving furnace system, and as shown in FIG.
A plurality of heaters 12 (in this example, 3 pairs of upper and lower heaters) are provided along the belt movement direction and whose temperature can be set individually.
...and those rotating helts 11 and heaters 12...
A controller 13 for controlling
As shown in the figure, two substrates (upper and lower) with excellent thermal conductivity (for example, non-oxide ceramic plates such as boron nitride and silicon nitride, carbon plates, carbon graphite plates, alumina plates, etc.) Width x thickness = 50mm x 50mm
X 0. 635 mm alumina plate) 14. In this example, a very thin spacer is placed between the 14 and 14 plates, each having a thickness of 0.635 m.
The working blocks 16 are held between the alumina plates (15° and 15 mm), and the working blocks 16 are continuously placed on the rotating belt 11.
The inside of the furnace 10 is opened from its population 10A to its outlet 10B.
It passes through at a predetermined time (speed). The relationship between the moving distance in the furnace 10 and the temperature T is schematically shown in, for example, FIG. It can be set as desired. That is, the chip-shaped second glass sheets S... sandwiched between the working blocks 16 introduced from the entrance 010A of the furnace 10 are heated during the preheating period up to point A in FIG. The temperature of the whole is gradually raised to just before the melting temperature (in this example, it is about 600°C below the softening point; in the case of the pNa glass responsive membrane, it is 700°C), and in the preheated state on the verge of melting, By applying a predetermined amount of heat energy during the extremely short surface melting period (about 10 seconds in this example) up to point B in Figure 5, only the surface (front and back surfaces) is completely melted. A high-speed surface heating treatment is performed for preheating, in which the material is melted with good uniformity and then solidified by reaching the 0 point (cooling point) in FIG. 5. In addition, in FIG. 3, 10a
is an air (or N2 gas) blower for the inlet air curtain, 1
0b is an air (or N7 gas) jet for the exit air curtain, 10C is a firing gas air (or N2 gas) jet, and IOD is a firing gas discharge pipe.

By the way, the belt moving furnace method mentioned above, similar to the preheating lamp heat irradiation method, uses a chip-shaped second glass sheet +-S.
It is particularly suitable for precision vitrification of the entire surface of the glass, and is extremely suitable for mass production. However, even in the preheating laser heat irradiation method and the preheating lamp heat irradiation method shown in FIGS. 1 and 2, the chip-shaped second glass sheet S or the heater block 2 or working board 7 that supports it is automatically It is possible to improve the mass production system by adding replacement handling equipment and the like.

In addition, if it is not necessary to manufacture the second glass sheet by the etching process, the first glass sheet after slicing by mechanical cutting is diced into chips, and the chip-shaped first glass sheet is As with the chip-shaped second glass sheet S, the glass sheet may be subjected to the high-speed surface heating treatment after the preheating.

〔Effect of the invention〕

As is clear from the detailed explanation above, according to the method for manufacturing ultra-thin flat glass according to the present invention, mechanical cutting means (and, if necessary, By first forming a glass sheet using a process (further etching treatment may also be applied) and then preheating the glass sheet and then subjecting it to high-speed surface heating treatment, we have created ultra-thin flat glass that was previously impossible to achieve. In other words, it is sufficiently thin and large, without microcracks or distortion, and without crystallization (devitrification).
It is now possible to easily and inexpensively produce ultra-thin flat glass that does not generate any oxidation, has a uniform composition, and has a sufficiently smooth and transparent surface, regardless of its composition. The excellent results have been demonstrated, making it possible to make a significant contribution to the production of glass response membranes (ion-responsive ultra-thin flat glass) required for sheet-type ion measurement electrodes, which has been a major concern for some time. .

[Brief explanation of the drawing]

Figures 1 to 5 show specific examples for carrying out high-speed surface heating treatment on preheating, which is a main step in the method for manufacturing ultra-thin flat glass according to the present invention, and Figure 1 shows the first embodiment. Figure 2 is a schematic system configuration diagram of the second embodiment, Figure 3 is a schematic system configuration diagram of the third embodiment, Figure 4 is a side view of its main parts, and Figure 5 is its schematic system configuration diagram. It is a graph showing an example of control characteristics. 6 and 7 are for explaining the technical background of the present invention and the problems of the prior art.
The figure shows a partial cross-sectional side view of a conventional general ion concentration measuring electrode, and Figures 7 (a) and 7 (b) show a vertical cross-sectional view and an external perspective view of a C-type composite electrode for salinity measurement, respectively. S...Glass sheet. Fig. 1 Fig. 2m *5 Fig. 6 Fig. 7 (A)

Claims (1)

[Claims] A glass block manufactured to have a predetermined composition is sliced by mechanical cutting means to a target thickness or, if this is not possible, as close as possible to the target thickness. A thick first glass sheet is manufactured, and if the first glass sheet is thicker than the target thickness, etching is further performed on the surface of the first glass sheet to achieve the target thickness. 2 glass sheets are manufactured, and then, in a state where the entire first or second glass sheet is preheated and raised to just before the melting temperature, a predetermined amount is further applied to the surface of the first or second glass sheet. 1. A method for producing ultra-thin flat glass, characterized by the step of melting only the surface of the first or second glass sheet and then solidifying it by applying heat energy of