JPH04152148A - Glazed substrate - Google Patents

Abstract

PURPOSE:To obtain a glazed substrate having a low thermal conductivity by providing an interposed layer having a low thermal conductivity between a glaze glass layer forming a topmost layer and a substrate body. CONSTITUTION:Between a glaze glass layer forming a topmost layer and a substrate body, an interposed layer having a thermal conductivity lower than that of either of the aforesaid glaze glass layer and substrate body is provided. The interposed layer is a low-thermal conductivity layer in which fine pores are dispersed. On the aforesaid glaze glass layer, a heating element is pattern- printed as an integrated circuit. In addition, since a heat generated by the heating element pattern-printed on the glaze glass layer is sufficiently inhibited from diffusing by the presence of the interposed layer, required temperature and heating value can be held in the heating element part with a low electric power and a low heating value.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a glazed substrate used for configuring an electronic circuit pattern, a heating element pattern, etc. on the surface thereof, and is effectively used, for example, in a thermal head such as a thermal printer. The present invention relates to a glazed substrate that can be used.

<Conventional technology and its challenges> In recent years, with the increase in speed and performance of thermal printers,
Glazed substrates used in printer heads are also required to have high performance and properties. Examples include high surface smoothness, high heat resistance, and high electrical insulation.

In response to these demands, conventionally, for example,
No. 453, JP 6343330, JP 61-13
Various proposals have been made for adjusting the composition of glaze glass, such as in No. 6937.

On the other hand, as another characteristic of glazed substrates used in thermal printer heads, from the viewpoint of energy saving, etc., there has recently been a demand for glazed substrates with low thermal conductivity, from which heat generated on the surface is difficult to dissipate.

However, many researchers have not yet provided a glaze glass having a composition that satisfies this requirement for low thermal conductivity. This is because glass is generally a material with low thermal conductivity, and its value is 2 x 10-'cat/g.
, sec, cm'C, and it is quite difficult to achieve a thermal conductivity that is about 50% or more lower than this while maintaining the above-mentioned properties such as high smoothness, high heat resistance, and high electrical insulation. This is because it is difficult.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a glazed substrate that maintains the required thermal properties and has a thermal conductivity sufficiently lower than that of conventional substrates.

<Means for Solving the Problems> In order to achieve the above object, the present inventor changed the conventional idea of adjusting the composition and processing method of glaze glass, and developed a multilayer structure in which multiple layers are laminated on the substrate body. The glazed substrate of the present invention has low thermal conductivity. That is, the first feature of the glazed substrate of the present invention is that an intervening layer having a lower thermal conductivity than the glazed glass layer and the substrate body is provided between the glazed glass layer forming the outermost surface layer and the substrate body. It is said that

In addition to the first feature, the glazed substrate of the present invention has a second feature in that the intervening layer is a low thermal conductivity layer in which fine pores are dispersed.

In addition to the first or second feature, the glazed substrate of the present invention has a third feature in that a heating element is pattern-printed as an integrated circuit on the glazed glass layer.

According to the first feature of the present invention, the intervening layer suppresses diffusion of heat generated in the glaze glass layer. Therefore, even if the amount of heat generated is small, that part can be effectively heated to a high temperature.

Further, according to the second feature of the present invention, since the intervening layer is formed with fine pores dispersed therein, the thermal conductivity can be physically reduced due to the presence of the fine pores, and the intervening layer can physically reduce the thermal conductivity. There is no need to adjust the material of the layer itself, or only a slight adjustment is required.

Therefore, a wide variety of materials can be used for the intervening layer. Furthermore, materials whose materials and components are adjusted to meet other required properties can be used for the intervening layer.

If micropores are dispersed in the glaze glass layer itself, the surface smoothness of the glaze glass layer will be lost.

Furthermore, according to the third feature of the present invention, the diffusion of heat generated in the pattern-printed heating element is sufficiently suppressed by the presence of the intervening layer, so that the required temperature and amount of heat can be achieved with low power and low calorific value. can be held in the heating element.

FIG. 1 shows a cross-sectional configuration diagram of a glazed substrate of the present invention.

1 is a glazed glass layer, 2 is an intervening layer, and 3 is a substrate body. A heating element pattern and other electronic circuit patterns (not shown) are printed on the glazed substrate.

As the glaze glass forming the glaze glass layer I, for example, alkali-free glass, lead-containing glass, etc. can be used, but the material of the glass and the processing method are not particularly limited. Of course, as the glaze glass, one with good surface smoothness, one with good electrical insulation properties for electronic circuits, and especially for the part of the thermal head, in addition to these, one with good heat resistance is used. As the main body 3, an alumina substrate can be used, for example, but other materials such as ceramic, glass, and various other materials that are generally used for electronic circuit boards can also be used.

As already mentioned, the intervening layer 2 is the glaze glass layer 1.
And the thermal conductivity is lower than that of the substrate body 3. The lower the thermal conductivity, the more difficult it is for heat to escape from the glaze glass layer 1, which is preferable.

When this intervening layer 2 is formed of a glass composition, it is a glass layer in which fine pores are dispersed. As already mentioned, the thermal conductivity of glass is generally 2×10-”cal/g,
sec, cmt, and it is substantially difficult to significantly reduce the thermal conductivity by compositional adjustment. The present inventor solved this problem by distributing micropores within the layer.
This was done to physically reduce the thermal conductivity. Since the thermal conductivity is made low by physical means, there is little need to adjust the components of the intervening layer 3. Therefore, the components of the intervening layer 3 can be adjusted to other required characteristics and properties.

The intervening layer 2 in which the fine pores are dispersed may be made by adding zirconia, forsterite, or other various additives to the glass composition. Similarly, as the intervening layer 2 in which micropores are dispersed, oxide ceramics with low thermal conductivity such as zirconia and forsterite, and other ceramics can be used.

Various means can be used to disperse micropores within the intervening layer 2. For example, 5iJa, S
Non-oxide ceramic powders such as iC and WC, sulfates, carbonates, nitrates, ammonium salts, polymer resin powders, and organic solvents are used as foaming materials, and this is mixed with raw glass and raw ceramics and then fired. This allows fine pores to be dispersed within the layer. That is, a paste prepared by mixing raw material glass or raw material ceramic with foaming material may be laminated on the substrate body and then fired. As another example of the means for dispersing micropores, the intervening layer 2 may be laminated on the substrate body 3 by plasma spraying or other physical methods, and micropores as structural defects may be introduced at the same time. can. The means for creating micropores in the intervening layer 2 in this way is not particularly limited. Further, the size of the micropores is not particularly limited as long as it affects the thermal conductivity.

As the intervening layer 2, when the glaze glass 1 is fired, the glaze glass 1 is
Things that do not react with, things that do not melt or soften (deform),
Alternatively, it is preferable to use a material that does not foam. This is because the properties of the glaze glass change when it reacts, deteriorating its insulation and other properties, and when it melts, softens, or foams, it adversely affects the smoothness of the glaze glass laminated thereon. Firing temperature of the above glaze glass (
As the intervening layer 2 that can have heat resistance at temperatures of 1,000 to 1,300° C., it is preferable to use crystallized glass and those to which inorganic substances are added as vitreous materials, and oxide ceramics such as zirconia and forsterite as ceramic materials. I can do it.

The crystallized glass used for the intervening layer 2 is a crystallized glass having a heat resistance temperature of 1100° C. or higher, since the firing temperature is 1100° C. or higher when the glaze glass layer 1 is alkali-free glass. It is preferable. In addition, when the glaze glass layer 1 is made of lead-containing alkali-free glass, the firing temperature is 900°C or higher.
Crystallized glass that is heat resistant even at temperatures above .degree. C. is preferred.

The purpose of dispersing the micropores in the intervening layer 2 is to effectively reduce the thermal conductivity of the intervening layer 2, and therefore the thermal conductivity of the intervening layer 2 may be lowered by other physical or chemical means. If possible, there is no need to use micropores. For example, instead of micropores, fine precipitates, crystallized substances, and other foreign substances can be physically removed.
It may be chemically dispersed, and if the material itself has a sufficiently low thermal conductivity, the above-mentioned micropores and foreign substances are not necessary, and the material itself can be dispersed without special treatment. It is preferable that the glaze glass layer 1 and the intervening layer 2, which can be used as the layer 2, have a coefficient of thermal expansion close to that of the substrate body 1. Otherwise, the substrate may warp or deform due to thermal fluctuations during firing or other uses.
A problem arises in that the glaze glass layer 1 cracks.

For example, when the substrate body 3 is made of alumina, the thermal expansion coefficient of the intervening layer 2 is 40 to 80X10-'/'C (room temperature to 40
0°C) is preferred.

As a means for laminating the intervening layer 2 and the glaze glass layer 1 on the substrate main body 3, first, an intervening layer material made of paste-like glass or ceramic is laminated on the substrate main body 3;
This can be dried and fired, then a paste of glazed glass material can be laminated thereon, dried and fired to complete the lamination. Further, by using crystallized glass having a low crystallization temperature as the intervening layer material, the intervening layer 2 and the glaze glass layer can be fired simultaneously in one step.

In this case, a paste-formed intervening layer material is first laminated on the substrate body 3 and dried, then a paste-formed glaze glass material is laminated thereon, and the whole is simultaneously fired. Further, as a laminating means, after laminating the intervening layer 2 on the substrate body 3 by a physical method such as plasma spraying or a chemical method, a paste-like glaze glass material may be laminated and fired. As described above, various methods can be used for laminating the intervening layer 2 and the glaze glass layer 1 on the substrate body 3, and the method is not limited.

The stacking height of the intervening layer 2 and the glaze glass layer 1 on the substrate body 3 is not particularly limited, and may be appropriately changed depending on the intended use. In addition, when the thickness of the lamination on the substrate body 3 is determined, by configuring the intervening layer 2 except for the minimum required for the glaze glass layer 1, it is possible to reduce the amount of the glaze glass layer 1 and to increase the overall thickness of the substrate. It is possible to further reduce thermal conductivity.

<Example> (1) Using alkali-free crystallized glass for the intervening layer 2,
As this alkali-free crystallized glass, 5iO
z45χ, A1zOi20χ, Ca020χ, TtOz
Zirconia (ZrOz 8mol
χYzoz)2χ was added, and 5% of acetone as an organic solvent (as a foaming agent) was added. The obtained mixed powder was then ground in a ball mill for 20 hours to give an average particle size of 5 μm.

Then, ethyl cellulose was added as an organic binder and terpineol was added as a solvent, and the mixture was dispersed and kneaded using three rolls to form a paste. The obtained paste was laminated to a thickness of 10 μm on an alumina substrate body 3 and dried.

On the other hand, an alkali-free glass was used for the brace glass layer 1, and the alkali-free glass contained 5ioz5 in weight%.
1.15χ, At2oz6.14χ, BzO+5.12
2, Ca010.2X, Ba025.58χ,
A material containing ZnO1,79X was ground in the same manner using a ball mill to give an average particle size of 5 μm. Then, ethylcellulose and terpineol were added in the same manner and kneaded to form a paste. This paste was printed and laminated to a thickness of 30 μm on top of the previously laminated and dried intervening layer paste, and co-fired at 1200° C. for 2 hours.

As a result, the surface of the obtained glazed substrate had bubbles, protrusions,
There are no appearance defects such as devitrification, and the thermal conductivity is 1. OX 10-'cat/g, sec, c++'
c, the value for the case of only the glaze glass layer is 2. OXl0-
It was about half or less compared to 3cal/g, sec, cm'c.

(2) Zirconia powder (ZrO, -8molχ'bo
z) A trace amount of fine powder SiC (1%) was added to 2%, wet-mixed to uniformly disperse it, and then made into a paste, which was screen printed to a thickness of 10 μm on the upper surface of the alumina substrate body. After baking this at 1300° C. for 2 hours, a 30 μm glaze glass was screen printed in the same manner as in Example (1) above, and baking was done at 1200° C. for 2 hours.

As a result, the obtained glazed substrate has a smooth surface,
The insulation and heat resistance were not inferior to those using only the glazed glass layer, and the thermal conductivity was less than half that of the glazed glass layer only.

(3) A zirconia fine powder was laminated to a thickness of 10 μm on the top surface of the alumina substrate body by plasma spraying, and the Example (
Glaze glass was screen printed to a thickness of 30 μm and fired in the same manner as in 1).

As a result, compared to the case of only a conventional glazed glass layer, smoothness, insulation properties, and heat resistance were not inferior, and thermal conductivity could be reduced to less than half.

<Effects> The present invention has the above configuration and operation, and according to the glazed substrate according to claim 1, the glazed glass layer and the substrate body are provided between the glazed glass layer forming the outermost surface layer and the substrate body. Since we have provided an intervening layer with a lower thermal conductivity than that of the glazed glass layer, the intervening layer can effectively suppress the diffusion of heat in the glazed glass layer, and as a result, the thermal conductivity of the surface is sufficiently lower than that of the conventional method. It has now become possible to provide an energy-saving glazed substrate that can effectively utilize the small amount of heat that is applied.

Further, according to the glazed substrate according to claim 2, in addition to the effect of the structure according to claim 1, the conductivity is physically reduced by introducing micropores, so that the components and materials of the intervening layer themselves can be reduced. Low thermal conductivity can be achieved without being too limited by Therefore, not only can a wide variety of materials be used, but also materials that can sufficiently meet other characteristics required as a substrate material can be used.

Further, according to the glazed substrate according to claim 3, in addition to the effects achieved by the configuration according to claim 1.2, the diffusion of heat generated by the heating element is effectively suppressed, and the amount of heat generated in the heating element is reduced. It can be used without loss.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional configuration diagram of a glazed substrate according to the present invention. 1: Glazed glass layer 2: Intervening layer 3: Substrate body

Claims (3)

[Claims] (1) A glazed substrate characterized in that an intervening layer having a lower thermal conductivity than the glazed glass layer and the substrate body is provided between the glazed glass layer forming the outermost surface layer and the substrate body. (2) The glazed substrate according to claim 1, wherein the intervening layer is a low thermal conductivity layer in which micropores are dispersed. (3) The glazed substrate according to claim 1 or 2, wherein a heating element is pattern-printed as an integrated circuit on the glazed glass layer.