JPH0433736B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] 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 the concentration of various ions 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 (so-called glass electrodes) such as PH measuring electrodes, for example, are equipped with a flame-making method (balloon method) at the tip of a support tube a made of electrically insulating glass, as shown in Figure 6. The formed hemispherical glass responsive membrane (ion responsive ultra-thin glass membrane) b is bonded, and internal electrodes c and internal liquid d are sealed therein. In this case, since the ion-responsive ultra-thin glass film b 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 degree of blowing or preventing the occurrence of micro-cracks when joining it to the support tube a requires considerable skill, and not only is it difficult to mass produce, making the manufacturing cost extremely high. Although the overall structure has to be large and there are many disadvantages in terms of operability and maintainability, anyway,
It was possible to realize an ion-responsive ultra-thin glass film b (semispherical) having the required film thickness (0.1 to 0.3 mm).

On the other hand, recently, as proposed in Japanese Patent Application No. 61-63564 filed by the applicant of the present application, a technology for turning the internal liquid into a gel state has been developed. For items that do not require a glass response membrane, such as a reference electrode or a composite electrode thereof, it is possible to make them into sheets, as shown in Figure 7 A and B, which reduces the overall structure and reduces manufacturing costs. Improvements in ease of use, operability, and maintainability have been achieved. In addition,
In the composite electrode for salinity measurement shown in Figure 7 A and B, e is a substrate made of vinyl chloride, etc., and a plurality of (four in this example) silver electrodes f... are screen-printed on the top surface. formed by, and
Each base end portion is formed into a lead portion g..., and each tip portion thereof is formed into an internal electrode portion h... coated with a film of silver chloride, and each of these internal electrode portions h... A support layer i made of vinyl chloride or the like is formed on the substrate e except for the existing portion by screen printing or the like. And j... are the basic internal liquids (for example, 3.3NKC with AgC supersaturation)
etc.) and gelling agents (e.g. agar, gelatin, etc.)
A gel-like internal liquid made by adding a gel evaporation inhibitor (such as glycerin or ethylene glycol), which is made into a paste by heating, is printed on each of the internal electrode parts h by screen printing or the like.
It is placed one on top of the other. Further, k, k and m, m are the response membranes made of, for example, an organic material and provided over the respective gel-like internal liquids i...
The liquid junction membrane is made of a porous material impregnated with KC, and is fixed to the support layer i with an adhesive or the like around the periphery. Further, n is a recess for injecting the test liquid formed on the surface side of the support layer i, and o
is a lid body which can be opened and closed for the recess n for injecting the test liquid, and one edge thereof is fixed to the upper surface of the support layer i, and p is an adhesive provided on the upper surface of the support layer i. layer, the lid body o is opened in the adhesive layer p, and one portion of the test liquid is poured into the recess n.
After injecting a droplet or so, the lid body o is tightly closed to bring the test liquid injection recess n into a sealed state. The sheet-type composite electrode for salinity measurement with such a configuration is constructed by closing the lid o to spread the test liquid onto each of the response membranes k, k and juncture membranes m, m, and then closing the lid. o is closely fixed to the adhesive layer p, and then this sheet-type composite electrode for salinity measurement is attached to the lead portion g of a measuring device body (not shown) configured in the shape of, for example, a card calculator.
The salinity of the test liquid can be measured by inserting and connecting it to the mounting part of the test 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 prices and improvements in operability and maintainability.
At present, the film thickness is close to the vitrification limit (0.1~
Because it is impossible to manufacture a flat glass responsive membrane (ion-responsive ultra-thin glass membrane) that requires a thickness of 0.3 mm, it has not yet been realized.

That is, in the past, thin glass sheets with a thickness of at least 1 mm were manufactured by the vertical pulling method, and thinner glass sheets (for example, those used for preparations) were produced using the vertical pulling method as much as possible. It was manufactured by further polishing thin plate glass. However, in that case, not only would the manufacturing cost be extremely high, but
Since relatively large irregularities and microcracks remain on the glass surface, it cannot be used as a glass response membrane for ion concentration measurement electrodes. This is because accurate measurements cannot be made because the sample liquid cannot be adsorbed and desorbed smoothly on a glass surface that is highly uneven and has microcracks.

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 glass is stretched by elevating the temperature above that temperature has been known for some time, but in the case of the former glass reshaping method, it is difficult to obtain ultrathin flat glass of sufficient size. However, it has the disadvantage that microcracks are likely to occur on the glass surface, and the latter preform annealing method requires extremely large-scale equipment and causes distortion in the finished ultra-thin flat glass. It has the disadvantage that it tends to remain. 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 composition having a narrow temperature range for molding operation, crystallization (devitrification) of the glass occurs, making it completely 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 circumstances, and its purpose is to prevent the occurrence of microcracks, distortions, or crystallization (devitrification) in glass of any composition. The objective of the present invention is to develop and provide a completely new method that can produce ultra-thin flat glass at a relatively low cost.

[Means for solving problems]

In order to achieve the above object, the method for manufacturing ultra-thin flat glass according to the present invention involves slicing a glass block manufactured to have a predetermined composition using a mechanical cutting means to achieve a target thickness or an undesirable thickness. In such a case, a first glass sheet with a thickness as close as possible to the target thickness is manufactured, and if the first glass sheet is thicker than the target thickness, the thickness of the first glass sheet is The surface is further etched to achieve the second target thickness.
A 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 predetermined amount is further applied 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 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 producing 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 having a predetermined composition (its production is easy, In addition, after preparing (no crystallization or devitrification occurs and good uniformity of composition is ensured),
The glass block is sliced by mechanical cutting means to produce a first glass sheet having a target thickness or, if this is not possible, a thickness as close as possible to the target thickness. Regardless of its composition, the first glass sheet can be formed with a minimum diameter of approximately 0.08 mm, regardless of its composition, 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 possible to obtain slices as thin as Moreover, it is possible to easily obtain a sufficiently large one without distortion or microcracks. However, the first
Since the surface of the glass sheet still has irregularities caused by mechanical cutting, it remains opaque (like ground glass) as it is, and is in a completed state that can be used, for example, as a glass response membrane for ion concentration measurement electrodes. It won't be.

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 very uneven temperature distribution can cause the glass to break, or if the target glass is thin or small, it can melt and condense, making it extremely difficult to do so. Proven.

The present invention solves this difficult problem by raising the temperature of the glass to be processed, that is, the entire first or second glass sheet, to just before the melting temperature, and then heating the surface of the glass while it is on the verge of melting. This problem was overcome by adding a predetermined amount of thermal energy to the problem in a short period of time.

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 (regenerated vitrification), and as a result,
It has sufficient thickness and size, has no microcracks or distortion, and does not cause crystallization (devitrification), which could not be achieved using any conventional method. It has become possible to easily and inexpensively produce ultrathin flat glass that satisfies the strict requirements of being sufficiently smooth and transparent, regardless of its composition.

Therefore, according to the method of the present invention, in particular, PH, pNa
Flat glass response membranes (ion-responsive ultra-thin flat glass) are necessary when constructing sheet-type electrodes for measuring various ion concentrations such as
It has now become possible to realize a sheet-type ion measurement electrode using it.

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

〔Example〕

Hereinafter, specific embodiments of the method for manufacturing ultra-thin flat glass according to the present invention will be described with reference to the drawings (FIGS. 1 to 5).

Here, we will explain the case of manufacturing an ultra-thin flat glass with length x width x thickness = 10 mm x 8 mm x 0.1 mm as an example of the PH glass response membrane required to construct a sheet-type PH measurement electrode. do.

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

First, after mixing predetermined ingredients and amounts of powder raw materials and melting and solidifying them in a platinum crucible, etc.,
By performing an annealing treatment, a large glass ingot of PH glass having a predetermined composition is manufactured. As a result, in this example, a large glass ingot with length x width x thickness = 328 mm x 93 mm x 23 mm was obtained.

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

Next, the large glass ingot is cut into a suitable cutting method 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, an outer peripheral cutting method, etc.). Divide into sized glass blocks. As a result, in this example, 14 glass blocks of length x width x thickness = 45 mm x 45 mm x 23 mm were obtained.

Subsequently, by slicing each of the above-mentioned glass blocks using the same mechanical cutting means, a first glass sheet having a thickness (0.2 mm) as close as possible to the target thickness (0.1 mm) is manufactured. As a result, in this example, a large number of first glass sheets having length x width x thickness = 45 mm x 45 mm x 0.2 mm were obtained.

Therefore, each of the first glass sheets still has a thickness (0.2 mm) larger than the target thickness (0.1 mm), and its surface has relatively large irregularities caused by the mechanical cutting. Because it remains, it is in an opaque (ground glass) state.

Therefore, each of the first glass sheets is
%NH4F aqueous solution, etc., and further a specified thickness (0.05 mm in this example) from the surface (both front and back sides).
By performing the etching process, a second glass sheet having the target thickness (0.1 mm) and having surface irregularities reduced to some extent is manufactured. Although this etching process makes it possible to obtain a second glass sheet that is thinner and has surface irregularities reduced to some extent, it is still in a translucent state and not in a completed state. As a result, in this example, a second glass sheet having dimensions of length x width x thickness = 45 mm x 45 mm x 0.1 mm was obtained.

Note that when cutting to the final target thickness by the mechanical cutting means, the first glass sheet having the target thickness is obtained only by the mechanical cutting means, so this etching process 2nd by
The glass sheet manufacturing process is not necessarily required.

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, a chip-shaped second glass sheet having the desired size and thickness of length x width x thickness = 10 mm x 8 mm x 0.1 mm 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 chip-shaped second glass sheet obtained as described above needs to be transparent and have a sufficiently smooth surface by eliminating any remaining unevenness on its surface, so it is necessary to make it transparent and have a sufficiently smooth surface. Surface treatment is performed by a novel heat treatment means.

In other words, the chip-like structure is designed to effectively prevent glass cracking and melting and condensation caused by rapid 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 applied a high-speed surface heating treatment under preheating to allow the material to dry and then solidify.

As a result, it has a sufficient size, does not cause microcracks, distortion, or crystallization (devitrification), and has a sufficiently smooth surface, which could not be achieved using any conventional method. It has now been possible to easily and inexpensively produce ultrathin flat glass that satisfies the strict requirements of being transparent and transparent, and can be used satisfactorily as a PH glass response membrane, regardless of its composition.

By the way, various methods can be considered as specific implementation means for the high-speed surface heating treatment under preheating, 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. 1, an XY table 1, a heater block 2 placed on the XY table 1, and a A temperature controller 3 for the block 2, a laser irradiation device 4 capable of irradiating a certain point on the XY table 1 with, for example, a CO ₂ laser R (several W to about 10 W is sufficient), and a temperature controller 3 for the XY table 1. A system is constituted of a regulator 3, a controller 5 for controlling the laser irradiation device 4, etc., and the chip-shaped second glass sheet S obtained as described above is placed on the heater block 2. Then, first, the temperature controller 3 for the heater block 2 is controlled by the controller 5 to preheat the entire chip-shaped second glass sheet S to just before the melting temperature (in this example, the temperature is below the softening point). Thereafter, 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 surface of the chip-shaped second glass sheet S on the heater block 2. Scanning the CO2 laser R at a predetermined speed (in this example, approximately several cm/sec) over the required location or the entire surface.
By applying a predetermined amount of thermal energy in a short period of time by irradiating the surface with a metal, a high-speed surface heating treatment is performed under preheating, in which only the surface is melted and then solidified. Generally, when light is irradiated onto glass, heat absorption occurs first at the interface (surface), so simply irradiating the CO2 laser R from one side of the chip-shaped second glass sheet S as described above , both the front and back sides can be processed at the same time. Further, this preheating laser heat irradiation method is particularly suitable when it is sufficient to precisely vitrify only a part (required part) of the surface of the chip-shaped second glass sheet S.

The other one (second embodiment) is a so-called preheating lamp heat irradiation method, as shown in Fig. 2.
A fixed base 6 made of a heat insulating material, a working board 7 made of a material with excellent heat resistance, thermal conductivity and heat dissipation and preferably black in color and placed on the base 6, and the Lamp light (e.g. halogen lamp light) on the working board 7
L can be focused, and its luminous output, light focusing degree,
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 L while gradually increasing the light emitting output while condensing the light to the same size or slightly larger than the chip-shaped second glass sheet S. The entire glass sheet S is heated slowly in advance 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 achieve a relatively high light emitting output. (In this example
By applying a predetermined amount of thermal energy by irradiating the entire surface of the chip-shaped second glass sheet S with lamp light L at a temperature of about 1200°C for a very short time (about a few seconds in this example), A high-speed surface heating treatment is performed under preheating, which melts only the surface with good uniformity and then solidifies it. In addition,
In this case as well, by simply irradiating the lamp light L from one side of the chip-shaped second glass sheet S, both the front and back sides can be processed 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. By performing scanning irradiation in this state, as with the preheated 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 achieved relatively easily. It is also possible to realize this with less energy consumption.

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, three pairs of upper and lower) provided along the direction of belt movement and whose temperature can be set individually, and a controller 13 for controlling the rotating belt 11 and the heaters 12... As shown in FIG. A board (for example, a non-oxide ceramic board such as boron nitride or silicon nitride, a carbon board, a carbon graphite board, an alumina board, etc.) In this example, the vertical
Width x thickness = 50mm x 50mm x 0.635mm alumina plate)
The working blocks 16 are sandwiched between the working blocks 14 and 14 through extremely thin spacers 15 and 15 (alumina plates with a thickness of 0.635 mm in this example), respectively. It is placed continuously on the rotating belt 11 and passed through the furnace 10 from the inlet 10A to the outlet 10B at a predetermined time (speed). The relationship between the moving distance D and the temperature T in the furnace 10 is schematically shown in, for example, FIG. It can be set arbitrarily. That is, the furnace 10
The chip-shaped second glass sheet S is held between the working blocks 16 introduced from the entrance 10A of the...
During the preheating period up to point A in Fig. 5, the entire temperature of each of the ... is gradually raised to just before the melting temperature (in this example, the temperature was set to about 600°C below the softening point. pNa glass response 700℃ for membranes),
In the preheated state on the verge of melting, a predetermined amount of thermal energy is applied during an extremely short surface melting period (about 10 seconds in this example) up to point B in FIG. A high-speed surface heating treatment is performed under preheating in which only the surfaces (front and back surfaces) are melted with good uniformity as a whole, and then solidified at point C (cooling point) in FIG. 5. In addition, in FIG. 3, 10a is an air (or N2 gas) blower for the inlet air curtain;
10b is air for outlet air curtain (or N2 gas)
The ejector 10C is a firing gas air (or N2 gas) ejector, and 10D is a firing gas discharge pipe.

By the way, like the preheating lamp heat irradiation method, the belt moving furnace method is particularly suitable for precision vitrification of the entire surface of the chip-shaped second glass sheet S, and is extremely suitable for mass production. suitable. However, the above figures 1 and 2
Even in the preheating laser heat irradiation method and the preheating lamp heat irradiation method shown in the figure, a handling device etc. for automatically replacing the chip-shaped second glass sheet S or the heater block 2 or working board 7 that supports it may be attached. According to
It is possible to build a mass production system.

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 preheating and high-speed surface heating treatment described above.

〔Effect of the invention〕

As is clear from the detailed description above, according to the method for manufacturing ultra-thin flat glass according to the present invention, a mechanical cutting means (and, if necessary, By converting the glass sheet into a glass sheet using a further etching process (additional etching process may also be applied) and then subjecting the glass sheet to high-speed surface heating treatment under preheating, we are able to create ultra-thin flat glass, which was previously impossible to achieve. In other words, the material must be sufficiently thin and large, without microcracks or distortion, without crystallization (devitrification), with a uniform composition, and with a sufficiently smooth and transparent surface. We produce satisfactory ultra-thin flat glass, regardless of its composition.
can be manufactured easily and cheaply, and therefore
This technology can 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.
This resulted in excellent effects.

[Brief explanation of drawings]

Figures 1 to 5 show specific examples for carrying out high-speed surface heating treatment under 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. 2 is a schematic system configuration diagram of the second embodiment,
Figure 3 is a schematic system configuration diagram of the third embodiment;
The figure is a side view of the main part, and FIG. 5 is a graph showing an example of its control characteristics. 6 and 7 are for explaining the technical background of the present invention and the problems of the prior art, and FIG. 6 is a partially cross-sectional side view of a conventional general ion concentration measuring electrode. 7A and 7B respectively show a longitudinal sectional view and an external perspective view of a sheet-type composite electrode for salinity measurement. S...Glass sheet.

Claims (1)

[Claims] 1. A glass block manufactured to have a predetermined composition is sliced by mechanical cutting means,
manufacturing a first glass sheet having a target thickness or, if it is not possible, a thickness as close as possible to the target thickness; and when the first glass sheet is thicker than the target thickness; further etches the surface of the first glass sheet to form a second glass sheet with a target thickness.
A 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 predetermined amount is further applied to the surface of the first or second glass sheet. 1. A method for producing ultra-thin flat glass, comprising the steps of melting only the surface of the first or second glass sheet and then solidifying it by applying thermal energy in a short period of time.