Reliably sensing bubble leveling means

摘要

A bubble leveling device includes a bubble level having a gas bubble formed on a liquid surface, an illuminator projecting light through or towards the gas bubble for producing an optical image of the gas bubble, and a sensor having a coordinate screen for locating the image of the gas bubble on the screen for checking the coincidence or deviation of the image with or from the coordinate center of the screen for reliably checking the horizontality or inclination angle as measured by the bubble leveling device.