| 摘要 |
PROBLEM TO BE SOLVED: To support a ceramic board properly even if it warps up or down. SOLUTION: A board-supporting device 140 has board-supporting members 150, 152 fixedly located on a holding plate 148. The board-supporting members 150, 152 are arranged in zigzag on the holding surface of the holding plate 148. The board-supporting members 150, 152 are members shaped like a pillar having a sectional area invariable in an axial direction and the board-supporting member 152 is larger in diameter and higher than the board-supporting member 150. The elastic modulus in the direction of compression of the board-supporting members 152 is larger that of the board-supporting members 150. In a case of supporting a ceramic board which has been warped downward, the top end surfaces 180, 181 of the board supporting members 150 and 152 contact the bottom surface of the ceramic board with the board-supporting members 150 elastically compressed. In a case of supporting a ceramic board which has been warped upward, only the top surfaces 180 of the board-supporting members 150 contact and support the bottom surface of the ceramic board. |
