| 摘要 |
PURPOSE:To make a rear panel light sharply by providing an outside rear panel made of material with higher mechanical strength and rigidity than glass and an inside rear panel made of glass. CONSTITUTION:When air is removed from an air vent hole 10 by a vacuum pump, since an airhole 11 is provided on an inside rear panel 9, the inside space 13 and gap 12 of the inside rear panel are almost simultaneously pressure- reduced and reach almost vacuum state finally. Accordingly, differential pressure is not activated on the inside rear panel 9 and there hardly occur deformation and stress. As a result, even if the inside rear panel 9 is made of glass, it can be thinned and made compact. The differential pressure that is almost equal to atmospheric pressure is activated on an outside rear panel 8. However, since it is made of high strength material and its allowable stress is high, there is no danger of it being destroyed. |
