JPS5842472A - Thermal head - Google Patents

Abstract

PURPOSE:To obtain a thermal head having excellent heat conductivity and excellent wear resistance and suitable for heat-sensitive recording by providing a carbon or carbon-based wear-resistant layer on a heating element layer on a base plate. CONSTITUTION:On a heating element layer 4 on a base plate 1, a carbon or carbon-based wear-resistant layer 5 is formed by a plasma gaseous phase method. In short, plasma is generated by producing glow or arc discharge by the addition of an electromagnetic energy of DC high-frequency (500kHz-50MHz) or micro-wave frequency (2.45GHz) under a reduced pressure of 0.01-10torr to activate and decomposite reactive gas, e.g., such hydrocarbon bases as ethylene, propane, etc., and thereby a film made of non-crystalline or semi-noncrystalline insulating carbon of based on a carbon containing 30mol% or less H and Si is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermal head for heat-sensitive recording, and in particular, the wear-resistant layer is mainly composed of carbon fiber or carbon, which has the highest thermal conductivity among solids and is the most wear-resistant. The purpose is to provide a barrier to the material.

In the present invention, the heating element layer is made of an amorphous (hereinafter referred to as amorphous) or a semi-amorphous (hereinafter referred to as SAS) having microcrystallinity of a size of 95 to 20 OA by plasma vapor phase heating at a temperature of 100 to 450oC. Good luck ha2
It is intended to be provided using a material whose main component is silicon or carbon, which is formed at a low temperature of 00 to 350 DC.

In the present invention, the wear-resistant layer or heat-generating layer is formed using a plasma vapor phase method, that is, under a reduced pressure of 0.01 to 10 torr, using direct current, high frequency (500 KM2 to 50 MH2) or microwave (
For example, by applying electromagnetic energy at a frequency of 2°45 GHz), a glow or arc discharge is generated to generate plasma,
By activating and decomposing the vaporized reactive gases such as hydrocarbon gases such as ethylene and propane by such electromagnetic energy, hydrogen and silicon are contained in the insulating carbon or carbon of the AS dimension or SAS in an amount of 30 mole or less. The purpose is to form a film whose main component is carbon.

The present invention 1 is characterized in that the carbon formed by plasma vapor phase method KJ has an energy band width of 2°3 eV or more, typically 3.
It is an insulator with eV and its thermal conductivity is typically 5°0 (W/cm deg), which is an extremely high value close to 6.60 (W/cm 60g) of diamond. have

In addition, we have found extremely excellent properties with hardness similar to diamond, typically 6500 kg/T1 m', and applied these properties to the thermal head to achieve excellent wear resistance and high-speed heat-sensitive response. It is something that has a certain sexuality.

Further, according to the present invention, the carbon produced at 450° C. or lower in ASi or SAS can be made to have no valent or heptavalent. For that purpose, use it as a heating element,
Furthermore, due to its mechanical properties, it has other characteristics such that it is not necessarily necessary to form a wear-resistant layer.

Furthermore, since the present invention uses the wear-resistant layer in a plasma vapor phase method under reduced pressure, it is possible to retain the same thickness on the sides of the heat generating layer as on the top surface.

Therefore, when this material is made by sputtering, normal pressure vapor phase, etc., a wear-resistant layer with a thickness of 2 μm or more on the top surface (0.2 μm or more on the side surfaces) is required to cover the side surfaces. . However, in the present invention, both the top and side surfaces are 0°]-〇. 3μ is sufficient, resulting in a thickness of about 1/10
This makes it possible to further improve the thermal response speed.

In the present invention, the reactive gas is a hydrocarbon such as ethylene (
0,HD Methane-based hydrocarbons (0,H, Ω, etc.) or tetramethylsilane ((C
H, C4S]), tetraethylsilane ((QeQ S
1) etc. may also be used. In the former case, carbon and hydrogen are 3
0 mol% or less Special K SAS 0.0] to 5 mol%
Although the carbon content was low, the covalent bond between carbon atoms was strong and it had physical properties similar to those of diamond. In the latter case, hydrogen is contained in a proportion of 0.01 to 20 molar proportions, and silicon is contained in a proportion of 1/3 to 1/3 or less of that of carbon, as shown in the drawings.

FIG. 1 shows a vertical sectional view of a thermal printer used in the present invention. Figure 1 (B) is A--A of Figure 1 (A).
' shows a cross section. (0) shows the cross section along B-B'.

In the drawing, a glazed glass layer (2), a heating element layer (4), an electrode (4), and an abrasion-resistant layer (5) are laminated on a substrate, particularly a ceramic substrate. Also, Figure 1 (
As shown in 0), the part where the thermal paper is rubbed is covered with a heating element layer (
3) An i=1 wear layer (5) is provided in contact with the top.

In the present invention, the wear-resistant layer (5) is made of carbon or a material mainly composed of carbon, and this material is formed by a plasma vapor phase method. A feature is that the thickness of the side portions of the heat generating layer can be made approximately equal to the thickness of the top surface of the heat generating layer.

This is because the reaction gas is under reduced pressure (0.01 to IC1 torr), and the mean free path of the reactive gas is long, so that even when performing a gas phase method, there is a large amount of wraparound to the sides. In addition, the plasma convulsion imparts a large amount of kinetic energy to the reactive gases that cause them to collide with each other, prompting them to fly in all directions.

Regarding the wear-resistant layer, it was produced as follows. That is, a substrate having a surface to be formed is sealed in a reaction container, and the reaction container is evacuated to 10 tOrr.
This substrate was heated to 200 to 350°C, for example 300°C, in a heating furnace at 100 to 450°C. After this, hydrogen gas was introduced into this atmosphere, and 1O-10
After setting it to torr, electromagnetic energy was applied using an induction method or a coupling method. For example], 3-56 MHz% 50-500 W
The actual distance between the electrodes was set to 15 to 150 cm. This is because the reactive energy generated when the carbon is turned into plasma is used to covalently bond the carbon atoms to each other.

If the output of the formed film is 50 to 150WK, it is A.
When s was 250 to 500 W, a structure in which SAS was mixed with SAS was observed in electron beam diffraction.

Furthermore, a carbide gas such as methylene or propane was introduced into this plasma atmosphere. Then, this reactive gas was dehydrogenated, and the carbon bonds were covalently bonded to each other, making it possible to form a carbon film on the surface to be formed.

When the temperature of the substrate was 100-200'O, the hardness was slightly low and the adhesion to the substrate was not necessarily favorable, but when the temperature of the substrate was 200''C or higher, especially 250-350°C (
/C had extremely stable and strong adhesion to the surface on which it was formed.

If the heating temperature is higher than /1450'o, stress will be generated due to the difference in thermal expansion coefficient with the substrate, creating a problem, so a coating formed at 250 to 450'C is an ideal wear-resistant material. .

The starting film quality was TMS ((OH,)Si), TES
(When (OLIQ, Si) was used, the formed film contained 15 to 30 Y of silicon and was mainly composed of carbon. Even this film had the same hardness as carbon alone.

Only carbon had a thermal conductivity of 5 W/cm deg, but 2
It was as low as ~3 W/cm cleg.

The carbon film formed as described above has a sail size of 05 to 0.2
Even if the thickness was 115 to 1/10 of the conventional thickness, it had wear resistance that could be used for more than 4 hours.

Example 2 In this example, a heat generating layer was formed using a thermal printer having the same hardness as in Example 1 using the same plasma vapor phase method as in Example 1.

The production was carried out using the plasma gas method under the same conditions as in Example 1. However, since it is necessary for the film to be formed to be conductive (resistive) and semiconductive, the film formed does not contain valent or V-valent impurities such as boron or phosphorous. .

That is, for the silicon film of f'+4, silane (S in Hzl, 2, nl) and silicon tetrafluoride are used as the starting materials, and similar coatings are prepared using
It was formed at 350°C. High frequency energy is 13.5
AJi or 50-20o with 6MHz as 10-50W
(9) SAS was formed as w. 1 valence impurity, for example, boron using BJ
H, was used after being slightly doped and non-doped as shown in the above ratio. Although hydrogen was contained in the formed film in an amount of 20 molar or less, it was released to the outside by generating heat.

At Ushida Carbon Takumi, the same methylene as in Example 1 was used. Here K BJ (, 10 fortune = 0.01~3%, pry
'CtHt·0.01 to 3 stripes were formed. As a result, an electrical conductivity of 0 to 10 (-0, cm) was obtained.

As is clear from the above explanation, since the present invention uses a plasma vapor phase method as its main feature, the conventional film forming method requires a substrate temperature of 100 to 45°C, typically 250 to 40°C, and 300°C. If you think about it, it is possible at a low temperature. In particular, the value of 5oo'c or less greatly reduces distortion due to thermal expansion when glass is used as a substrate material, and prevents major defects such as warping of the substrate due to conventional high-temperature processing. The heat generating part of the W-?iv printer could only produce 24 units of lrflm, but now it can be increased to 24 units.

As is clear from the above explanation, the present invention has an energy band r]2゜OeV or more, typically 25.5 to 3eV.
The invention is characterized in that insulating, translucent carbon having the following properties is used as the wear-resistant material, and that carbon or a resistor or semiconductor containing carbon as a main component is used as the heat generating layer. To this end, the present invention uses a plasma vapor phase method to form one or both of them, and can be formed at a temperature of 500'O or less, which is 300 to 500 IC lower than the temperature at which the substrate is formed using a conventional vapor phase method. It offered great freedom in material selection and was extremely low-cost.

The present invention mainly describes the plasma vapor phase method.

However, as long as such wear resistance can be obtained, ion blasting, other electromagnetic energy such as plasma or laser, or optical energy may be used.

The structure shown in FIG. 1 in the embodiment of the present invention shows one example, and the heat generating layer may be a single crystal transistor structure, and it can be used in a silicon mesa structure, a planar structure, etc. .

[Brief explanation of the drawing]

FIG. 1 shows a vertical sectional view of the thermal printer of the present invention.

Claims (1)

[Scope of Claims] 1. A thermal head characterized in that a wear-resistant layer containing carbon or carbon as a main component is provided on a heating element layer on a substrate. 2. A thermal head characterized in that a heating element layer mainly composed of carbon or silicon and having an amorphous or microcrystalline semi-amorphous structure is provided on a substrate. 3. A thermal head according to claim 2, further comprising a heating layer mainly composed of carbon or silicon doped with 0.01 to 3 parts of a valent or V-valent impurity. 4. A thermal head according to claim 1 or 2, characterized in that hydrogen or a halogen element is added in a molar proportion of 0.01 to 20.