| 摘要 |
PROBLEM TO BE SOLVED: To provide a dimensional ratio of a board effective for preventing the oxidation of the contact point of an electrode of a heating unit and a connector of power supply part, while overcoming the heat-shock by dint of the enhancement of mechanical strength by using aluminium nitride, silicon nitride, or silicon carbide as a principal element of the board, and by controlling the heat conductivity by adding some appropriate material, and by making the temperature gradient between the heating unit and the electrode gradual. SOLUTION: Making the distance between the starting point of contact of the heating unit 2 and the electrode 3 of circuit, and the end of the ceramics board 1a at the electrode 3 side as A, and the thickness of the ceramics board as B, the shape of the ceramics heater with an electrode and a heating unit on the ceramics board is formed as A/B>=20, and the heat conductivity of the ceramics board 1a is adjusted to 30-80 W/m.k. |
