Photoelectric position measuring system using gratings having specified dimensions to suppress harmonics
First Claim
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1. A photoelectric measuring system comprising:
- a light source having a plurality of light emitting areas which are separated from each other by non-emitting areas in the measuring direction;
a movable scale having a periodic graduation positioned to receive light emitted from the light-emitting areas of the light source; and
a scanning plate used to scan the scale and generate at least one position-dependent scanning signal, the scanning plate having a plurality of light sensitive areas which are separated from each other by non-sensitive areas in the measuring direction,wherein the light-emitting areas of the light source are dimensioned to suppress predetermined orders of harmonics and the light sensitive areas of the scanning plate are dimensioned to suppress predetermined additional orders of harmonics wherein if the predetermined orders suppressed by the light source are even ordered then the predetermined orders suppressed by the scanning plate are odd ordered and if the predetermined orders suppressed by the light source are odd ordered, then the predetermined orders suppressed by the scanning plate are even ordered.
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Abstract
A light source which emits light in strips is provided for illuminating a scale of a photoelectric position measuring system. The light modulated by the scale is converted into a sinusoidal scanning signal by a scanning plate. The scanning plate is a semiconductor substrate structured in strips. The width (A) of the light-emitting areas and the width (B) of the interspersed non-emitting areas of the light source is such that defined harmonics are filtered out of the scanning signal. The scanning plate is of such configuration that further harmonics are suppressed.
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Citations
18 Claims
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1. A photoelectric measuring system comprising:
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a light source having a plurality of light emitting areas which are separated from each other by non-emitting areas in the measuring direction; a movable scale having a periodic graduation positioned to receive light emitted from the light-emitting areas of the light source; and a scanning plate used to scan the scale and generate at least one position-dependent scanning signal, the scanning plate having a plurality of light sensitive areas which are separated from each other by non-sensitive areas in the measuring direction, wherein the light-emitting areas of the light source are dimensioned to suppress predetermined orders of harmonics and the light sensitive areas of the scanning plate are dimensioned to suppress predetermined additional orders of harmonics wherein if the predetermined orders suppressed by the light source are even ordered then the predetermined orders suppressed by the scanning plate are odd ordered and if the predetermined orders suppressed by the light source are odd ordered, then the predetermined orders suppressed by the scanning plate are even ordered. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A photoelectric measuring system comprising:
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a light source having a plurality of light emitting areas which are separated from each other by non-emitting areas in the measuring direction; a scale having a periodic graduation positioned to receive light emitted from the light emitting areas of the light source; and a scanning plate used to scan the scale and generate at least one positioned-dependent scanning signal, the scanning plate having a plurality of light sensitive areas which are separated from each other by non-sensitive areas in the measuring direction, wherein the light-emitting areas of the light source are dimensioned to suppress whole number multiples of the third harmonic and the light sensitive areas of the scanning plate are dimensioned to suppress even-numbered harmonics.
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16. A photoelectric measuring system comprising:
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a light source having a plurality of light emitting areas which are separated from each other by non-emitting areas in the measuring direction; a scale having a periodic graduation positioned to receive light emitted from the light emitting areas of the light source; and a scanning plate used to scan the scale and generate at least one positioned-dependent scanning signal, the scanning plate having a plurality of light sensitive areas which are separated from each other by non-sensitive areas in the measuring direction, wherein the light-emitting areas of the light source are dimensioned to suppress even-numbered harmonics and the light sensitive areas of the scanning plate are dimensioned to suppress whole number multiples of the third harmonic.
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17. A photoelectric measuring system comprising:
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a light source having a plurality of light emitting areas which are separated from each other by non-emitting areas in the measuring direction; a movable scale having a periodic graduation positioned to receive light emitted from the light-emitting areas of the light source; a scanning plate used to scan the scale and generate at least one position-dependent scanning signal, the scanning plate having a plurality of light sensitive areas which are separated from each other by non-sensitive areas in the measuring direction, wherein the light-emitting areas of the light source are dimensioned to suppress predetermined orders of harmonics and the light sensitive areas of the scanning plate are dimensioned to suppress predetermined additional orders of harmonics wherein the light-emitting areas of the light source and the light sensitive areas of the scanning grating are disposed side by side in the same plane. - View Dependent Claims (18)
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Specification