| 摘要 |
<p>PURPOSE:To accurately detect various movements of a ruler by disposing slits in which lights of the number proportional to the graduation of the ruler are passed at an equal interval in the length direction of the ruler, and sandwiching the slits between an optical sensor and a light source. CONSTITUTION:Slits 1 in which lights of the number proportional to the graduation of a ruler 7 are passed are formed and disposed at an equal interval in the length direction of the ruler 7 inside two parallel straight lines with the line of the ruler 7 in a square shape inside the two lines by the two sides of both the sides of the slits 1. The initial slit 2 of the graduation of the ruler 7 is formed in the shape in which the slit 1 is longitudinally split and the two split slits are stepwisely deviated in the length direction of the ruler 7. The slit 4 has an area smaller than that split longitudinally of the slit 2, and is longitudinally reduced in a slender state, and mounted at optical sensors 5, 6 as photoreceivers. When the ruler 7 is extended or contracted, two signals obtained by the passage of the light through the slits 4 become the same phase at the slit 2. At the other slits, the signals have deviated phases corresponding to the deviations to be measured.</p> |
