US 6,151,128 A · Optical position indicator · patentgrep

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Abstract

An optical position measuring system that has a scale graduation with a graduation period, TP, and connected with a first object that has a graduation and a scanning unit connected to a second object that moves relative to the first object, so that there is a displacement between the scale graduation and the scanning unit. The scanning unit includes a scanning plate with a first and second scanning fields that are arranged offset from each other in a measuring direction (x) by a distance, D. A first deflection element associated with the first scanning field and a second deflection element associated with the second scanning field, wherein the first and second deflection elements spatially separate the phase-shifted partial signals from the first and second scanning fields. First and second detector elements are placed downstream of the scanning plate and associated with the first scanning field. Third and fourth detector elements are placed downstream of the scanning plate and associated with the second scanning field. The first and second scanning fields are arranged on the scanning plate so that the offset distance D=TP/2*(N+1/4), wherein N=0, 1, 2, . . .

Claims31

Dependent claims

An optical position measuring system for detecting the relative position of a first object and a second object which are movable in respect to each other, comprising:

a scale graduation with a graduation period, TP, and connected with a first object;
a scanning unit connected to a second object that moves relative to the first object, so that there is a displacement between the scale graduation and the scanning unit, wherein the scanning unit comprises a scanning plate that comprises a first scanning field and a second scanning field that are arranged offset from each other in a measuring direction (x) by a defined distance, D, so that definitely phase-shifted partial signals, which are modulated as a function of the displacement can be associated with the first and second scanning fields;
a first deflection element associated with the first scanning field;
a second deflection element associated with the second scanning field, wherein the first and second deflection elements spatially separate the phase-shifted partial signals from the first and second scanning fields;
a first detector element placed downstream of the scanning plate and associated with the first scanning field;
a second detector element placed downstream of the scanning plate and associated with the first scanning field, wherein the first detector element and the second detector element detect the spatially separated phase-shifted partial signals in different spatial directions;
a third detector element placed downstream of the scanning plate and associated with the second scanning field;
a fourth detector element placed downstream of the scanning plate and associated with the second scanning field, wherein the third detector element and the fourth detector element detect the spatially separated phase-shifted partial signals in different spatial directions;
and
wherein the first, second, third and fourth detector elements are wired together so that two output signals, which are phase-shifted by 90.degree. relative to one another, are generated at an output side of the optical position measuring system;
and
wherein the first and second scanning fields are arranged on the scanning plate so that the offset distance D=TP/2*(N+1/4), wherein N=0, 1, 2, . . . .

9 more elements

An optical position measuring system for detecting the relative position of a first object and a second object which are movable in respect to each other, comprising:

a scale graduation with a graduation period, TP, and connected with a first object;
a scanning unit connected to a second object that moves relative to the first object, so that there is a displacement between the scale graduation and the scanning unit, wherein the scanning unit comprises a scanning plate that comprises a first scanning field and a second scanning field that are arranged offset from each other in a measuring direction (x) by a defined distance, D, so that definitely phase-shifted partial signals, which are modulated as a function of the displacement can be associated with the first and second scanning fields;
a first deflection element associated with the first scanning field;
a second deflection element associated with the second scanning field, wherein the first and second deflection elements spatially separate the phase-shifted partial signals from the first and second scanning fields:
a first detector element placed downstream of the scanning plate and associated with the first scanning field;
a second detector element placed downstream of the scanning plate and associated with the first scanning field, wherein the first detector element and the second detector element detect the spatially separated phase-shifted partial signals in different spatial directions;
a third detector element placed downstream of the scanning plate and associated with the second scanning field;
a fourth detector element placed downstream of the scanning plate and associated with the second scanning field, wherein the third detector element and the fourth detector element detect the spatially separated phase-shifted partial signals in different spatial directions;
and
wherein the first, second, third and fourth detector elements are wired together so that two output signals, which are phase-shifted by 90.degree. relative to one another, are generated at an output side of the optical position measuring system;
and
wherein the first and second scanning fields are arranged on the scanning plate so that the offset distance D=TP/2*(N+1/4) wherein N=0, 1, 2, . . . ;
and
wherein the first and second scanning fields are optimized in respect to the +1st and -1st order of diffraction, so that a phase shift of 120.degree. exists between the partial signals of these orders of diffraction.

11 more elements

An optical position measuring system for detecting the relative position of a first object and a second object which are movable in respect to each other, comprising:

a scale graduation with a graduation period, TP, and connected with a first object;
a scanning unit connected to a second object that moves relative to the first object, so that there is a displacement between the scale graduation and the scanning unit, wherein the scanning unit comprises a scanning plate that comprises a first scanning field and a second scanning field that are arranged offset from each other in a measuring direction (x) by a defined distance, D so that definitely phase-shifted partial signals which are modulated as a function of the displacement can be associated with the first and second scanning fields;
a first deflection element associated with the first scanning field;
a second deflection element associated with the second scanning field, wherein the first and second deflection elements spatially separate the phase-shifted partial signals from the first and second scanning fields;
a first detector element placed downstream of the scanning plate and associated with the first scanning field;
a second detector element placed downstream of the scanning plate and associated with the first scanning field, wherein the first detector element and the second detector element detect the spatially separated phase-shifted partial signals in different spatial directions;
a third detector element placed downstream of the scanning plate and associated with the second scanning field;
a fourth detector element placed downstream of the scanning plate and associated with the second scanning field, wherein the third detector element and the fourth detector element detect the spatially separated phase-shifted partial signals in different spatial directions;
and
wherein the first second, third and fourth detector elements are wired together so that two output signals, which are phase-shifted by 90.degree. relative to one another, are generated at an output side of the optical position measuring system;
and
wherein the first and second scanning fields are arranged on the scanning plate so that the offset distance D=TP/2*(N+1/4), wherein N=0, 1, 2, . . .;
and
wherein the first deflection element comprises a first prism;
and
wherein the second deflection element comprises a second prism.

13 more elements

An optical position measuring system for detecting the relative position of a first object and a second object which are movable in respect to each other, comprising:

a scale graduation with a graduation period, TP, and connected with a first object;
a scanning unit connected to a second object that moves relative to the first object, so that there is a displacement between the scale graduation and the scanning unit wherein the scanning unit comprises a scanning plate that comprises a first scanning field and a second scanning field that are arranged offset from each other in a measuring direction (x) by a defined distance, D, so that definitely phase-shifted partial signals, which are modulated as a function of the displacement can be associated with the first and second scanning fields;
a first deflection element associated with the first scanning field;
a second deflection element associated with the second scanning field, wherein the first and second deflection elements spatially separate the phase-shifted partial signals from the first and second scanning fields;
a first detector element placed downstream of the scanning plate and associated with the first scanning field;
a second detector element placed downstream of the scanning plate and associated with the first scanning field, wherein the first detector element and the second detector element detect the spatially separated phase-shifted partial signals in different spatial directions, and wherein the first detector element is wired anti-parallel with the second detector so that a resulting output signal associated with the first scanning field is generated, and
a third detector element placed downstream of the scanning plate and associated with the second scanning field;
a fourth detector element placed downstream of the scanning plate and associated with the second scanning field, wherein the third detector element and the fourth detector element detect the spatially separated phase-shifted partial signals in different spatial directions, and wherein the third detector element is wired anti-parallel with the fourth detector so that a resulting output signal associated with the second scanning field is generated;
and
wherein the resulting output signals of the first and second scanning fields have a phase- shift of 90.degree. with respect to each other and are generated at an output side of the optical position measuring system.

7 more elements

An optical position measuring system for detecting the relative position of a first object and a second object which are movable in respect to each other, comprising:

a scale graduation with a graduation period, TP, and connected with a first object;
a scanning unit connected to a second object that moves relative to the first object, so that there is a displacement between the scale graduation and the scanning unit wherein the scanning unit comprises a scanning plate that comprises a first scanning field and a second scanning field that are arranged offset from each other in a measuring direction (x) by a defined distance, D, so that definitely phase-shifted partial signals, which are modulated as a function of the displacement can be associated with the first and second scanning fields;
a first deflection element associated with the first scanning, field;
a second deflection element associated with the second scanning field, wherein the first and second deflection elements spatially separate the phase-shifted partial signals from the first and second scanning fields;
a first detector element placed downstream of the scanning plate and associated with the first scanning field;
a second detector element placed downstream of the scanning plate and associated with the first scanning field, wherein the first detector element and the second detector element detect the spatially separated phase-shifted partial signals in different spatial directions, and wherein the first detector element is wired anti-parallel with the second detector so that a resulting output signal associated with the first scanning field is generated, and
a third detector element placed downstream of the scanning plate and associated with the second scanning field;
a fourth detector element placed downstream of the scanning plate and associated with the second scanning field, wherein the third detector element and the fourth detector element detect the spatially separated phase-shifted partial signals in different spatial directions, and wherein the third detector element is wired anti-parallel with the fourth detector so that a resulting output signal associated with the second scanning field is generated;
and
wherein the resulting output signals of the first and second scanning fields have a phase- shift of 90.degree. with respect to each other and are generated at an output side of the optical position measuring system;
and
wherein the first and second scanning fields are optimized in respect to the +1st and -1st order of diffraction, so that a phase shift of 120.degree. exists between the partial signals of these orders of diffraction.

9 more elements

An optical position measuring system for detecting the relative position of a first object and a second object which are movable in respect to each other comprising:

a scale graduation with a graduation period, TP, and connected with a first object;
a scanning unit connected to a second object that moves relative to the first object, so that there is a displacement between the scale graduation and the scanning unit wherein the scanning unit comprises a scanning plate that comprises a first scanning field and a second scanning field that are arranged offset from each other in a measuring direction (x) by a defined distance, D, so that definitely phase-shifted partial signals which are modulated as a function of the displacement can be associated with the first and second scanning fields;
a first deflection element associated with the first scanning field;
a second deflection element associated with the second scanning field, wherein the first and second deflection elements spatialy separate the phase-shifted partial signals from the first and second scanning fields;
a first detector element placed downstream of the scanning plate and associated with the first scanning field;
a second detector element placed downstream of the scanning plate and associated with the first scanning field, wherein the first detector element and the second detector element detect the spatially separated phase-shifted partial signals in different spatial directions, and wherein the first detector element is wired anti-parallel with the second detector so that a resulting output signal associated with the first scanning field is generated, and
a third detector element placed downstream of the scanning plate and associated with the second scanning field;
a fourth detector element placed downstream of the scanning plate and associated with the second scanning field, wherein the third detector element and the fourth detector element detect the spatially separated phase-shifted partial signals in different spatial directions, and wherein the third detector element is wired anti-parallel with the fourth detector so that a resulting output signal associated with the second scanning field is generated;
and
wherein the resulting output signals of the first and second scanning fields have a phase- shift of 90.degree.0 with respect to each other and are generated at an output side of the optical position measuring system;
and
wherein the first deflection element comprises a first prism;
and
wherein the second deflection element comprises a second prism.

11 more elements

Dependencies are inferred from the claim text.