| 摘要 |
PROBLEM TO BE SOLVED: To provide an inexpensive level of a simple constitution which can be handled even by a worker alone. SOLUTION: The level which keeps a liquid and an air bubble sealed in a window formed in a curved surface, and the position of the air bubble visually observed through the window to verify horizontality, comprises a light-emitting element arranged above the center of the window formed in the curved surface, a light-receiving element for receiving reflected light of light emitted from the light-emitting element and reflected by the interface of the air bubble and the liquid, and a sound generator for producing sound when the light-receiving element receives the reflected light. COPYRIGHT: (C)2011,JPO&INPIT |
