| 摘要 |
<p>Photoelectric conversion signals (I<SUB>a</SUB>,I<SUB>b</SUB>,I<SUB>c</SUB>,I<SUB>d</SUB>) from a light receiving element (26) are subjected to an arithmetic process to provide two signals (I<SUB>A</SUB>,I<SUB>B</SUB>), from which a signal (I<SUB>AB</SUB>) is generated and then outputted from an encoder (10). This signal (I<SUB>AB</SUB>) includes a time(t)-dependent term that is 4d*sin(?t) as shown in an expression (7). On the other hand, the signals (I<SUB>A</SUB>,I<SUB>B</SUB>) have their respective time(t)-dependent terms that are 2d*sin(?t) as shown in expressions (5,6), so that the signal (I<SUB>AB</SUB>) varies, relative to the signals (I<SUB>A</SUB>,I<SUB>B</SUB>), similarly to a case where the modulation factor is substantially doubled. Therefore, in a case of determining, based on the signal (I<SUB>AB</SUB>), the position of a moving scale (24), it is possible to precisely determine the position of the moving scale (24) to a similar degree to the case where the modulation factor is doubled.</p> |
| 申请人 |
SENDAI NIKON CORPORATION;MAKINOUCHI, SUSUMU;IMAI, TORU;WATANABE, AKIHIRO |
发明人 |
MAKINOUCHI, SUSUMU;IMAI, TORU;WATANABE, AKIHIRO |
