| 摘要 |
PROBLEM TO BE SOLVED: To provide a light shielding device formed in a simple structure and preventing a head clearance from being reduced in construction machinery having a roof window at a cab. SOLUTION: The roof window 14 of the cab is formed of a liquid crystal glass 15, and the liquid crystal glass 15 is formed by sticking a liquid crystal panel 17 on the front or rear surface of a reinforced glass 16. The light shielding device 30 is formed of a control circuit 18 for controlling the flow of current to the liquid crystal panel 17, a power supply device 19, and a switch 20. The switch 20 is installed at a position where an operator can easily operate the switch. Since the liquid crystal panel 17 is transparent when the switch 20 is turned off, the liquid crystal glass 15 is brought into a translucent state. When the switch 20 is turned on, the liquid crystal panel 17 is energized and the liquid crystal panel 17 becomes opaque to lower a light transmittance. Thus, the liquid crystal glass 16 is changed in a light shielded state. COPYRIGHT: (C)2003,JPO
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