| 摘要 |
A display panel made of two sheets 11 of plastic material welded together at the sides only allows a post to be passed through the central gap to which it can then be secured as by a bolt. The panels 11 are welded in a continuous process in apparatus having infra-red heaters 115 which heat the panels locally in strips, at adjacent edge regions, the surrounding parts of the panels 11 being cooled by cooling blocks 102, 103, 104, 117 so that the major surfaces are cooled and remain undistorted during heating. The panels can then be printed. |
