| 摘要 |
PURPOSE:To make temperature control unnecessary and melt-fix a transparent glass to a metallic ring strongly by supporting the metallic ring in a through hole with a space left under the metallic ring so that the top plate part of the metallic ring is turned down and placing a transparent glass disc on the inside face of the top plate part and heating it in the state where the circumferential edge part is pressed with a jig. CONSTITUTION:A metallic ring 1 is fitted to a through hole 12 of a lower seal- fixing jig 11 with a space left under the metallic ring so that a top plate part 3 is turned down. A transparent glass disc 60a is placed on the inside face of the top plate part 3, and an upper seal-fixing jig 20 which has a pressing part 21 on the circumferential edge and has a space 22 in the center and has a step part 23 on the outside is placed on this disc 60a, and they are heated. Dimensions (g) of the gap between the upper face of a flange part 5 and the lower face of the step part 23 of the upper seal-fixing jig 20 are set to a value smaller than the thickness of the transparent glass disc 60a. The transparent glass disc 60a is melted and is pressed and shaped by the pressing part 21 of the upper seal-fixing jig 20, thus obtaining a lens cap provided with a lens-shaped transparent glass 60. |
