| 摘要 |
PURPOSE:To increase the accuracy of distance measurement, by changing the distribution of luminance of the emitted body of a projector to produce sharp peak, in an optical distance instrument. CONSTITUTION:L=D/tantheta is obtained, where L is the distance between the lens 4 and the measured body 1, D is the distance between the lenses 2 and 4, and the swing angle of the projector 3 is theta. Taking a fine region at the duplicated part between the emitted surface 6 and the photo detection range 7, when the center distance between the emitted surface 6 and the range 7 is d, the output of photo detection is the sum of the outputs of the fine regions. Almost uniform distribution of intensity of illumination is given to the emitted surface by using LED having the luminance distribution high in the circumference of the light emitting surface and low in the center resulting that the photo detection output around the peak is reduced and the sharpness is increased. |
