Position detecting apparatus
First Claim
1. A position detecting apparatus comprising:
- an optical scale having a grid pattern, said optical scale being movable in conjunction with a moving member, said grid pattern being formed as a scale graduation and having grid segments disposed at a predetermined pitch;
scale detecting means including;
a mask having an opening with a width which is substantially one-half the pitch of said grid segments and a photoelectric element being masked by said mask, said scale detecting means converting light which has passed through said optical scale and said opening of said mask to an analog signal which corresponds to the pitch of said grid segments said analog signal having a plurality of level signal components;
digitizing means for extracting selected signal components from said level signal components of said analog signal of said scale detecting means, which correspond to the pitch of said grid segments, said digitizing means converting said signal components to digital data; and
position information means for converting said digital data of said digitizing means to position information of said moving member.
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Accused Products
Abstract
A position detecting apparatus provided with a photosensor for optically detecting the scale pattern of an optical scale which moves together with the optical head of the optical disk instrument, and generating an analog signal which corresponds to a pitch of the scale graduation. The photosensor has a light receiving surface, whose width is half the pitch of the scale graduation, and the analog signal of the photosensor is converted to digital signals by means of an A/D converter the digital signals corresponding to a pluralty of level signal components of the analog signal. The digital data thus obtained are added or subtracted according to the moving direction of the optical head, thus enabling the position of the optical head to be detected.
17 Citations
3 Claims
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1. A position detecting apparatus comprising:
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an optical scale having a grid pattern, said optical scale being movable in conjunction with a moving member, said grid pattern being formed as a scale graduation and having grid segments disposed at a predetermined pitch; scale detecting means including;
a mask having an opening with a width which is substantially one-half the pitch of said grid segments and a photoelectric element being masked by said mask, said scale detecting means converting light which has passed through said optical scale and said opening of said mask to an analog signal which corresponds to the pitch of said grid segments said analog signal having a plurality of level signal components;digitizing means for extracting selected signal components from said level signal components of said analog signal of said scale detecting means, which correspond to the pitch of said grid segments, said digitizing means converting said signal components to digital data; and position information means for converting said digital data of said digitizing means to position information of said moving member. - View Dependent Claims (2, 3)
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Specification