Two-dimensional absolute encoder and scale therefor

A two-dimensional absolute encoding method of obtaining absolute positions in a first direction and a second direction of a scale, wherein, on the scale, a plurality of marks are two-dimensionally arranged with a predetermined space therebetween at a predetermined pitch along the first direction and the second direction, the method comprising steps of:

• detecting a first number of marks arranged in the first direction, and a second number of marks arranged in the second direction;
• and
• obtaining absolute positions of the scale in the first direction and the second direction based on the detected first number of marks and the detected second number of marks, respectively,
• wherein
• each of the plurality of marks has one of a plurality of characteristics corresponding to pairs of information of a first quantized code and information of a second quantized code, wherein the first quantized code is one of a plurality of first quantized codes which are defined on the scale along the first direction, each first quantized code sequence included in the plurality of first quantized codes indicates a first coordinate of the scale in the first direction, the second quantized code is one of a plurality of second quantized codes which are defined on the scale along the second direction, and each second quantized code sequence included in the plurality of second quantized codes indicates a second coordinate of the scale in the second direction, and
• the first quantized code sequence is generated based on detection of the first number of marks and information of the pairs corresponding to the characteristics, the absolute position of the scale in the first direction is obtained based on the first quantized code sequence, the second quantized code sequence is generated based on detection of the second number of marks and the information of the pairs corresponding to the characteristics, and the absolute position of the scale in the second direction is obtained based on the second quantized code sequence.

A scale for use in a two-dimensional absolute encoding method, the method obtaining absolute positions in a first direction and a second direction of a scale, wherein, on the scale, a plurality of marks are two-dimensionally arranged with a predetermined space therebetween at a predetermined pitch along the first direction and the second direction, the method comprising steps of:

• detecting a first number of marks arranged in the first direction, and a second number of marks arranged in the second direction;
• and
• obtaining absolute positions of the scale in the first direction and the second direction based on the detected first number of marks and the detected second number of marks, respectively,
• wherein
• each of the plurality of marks has one of a plurality of characteristics corresponding to pairs of information of a first quantized code and information of a second quantized code, wherein the first quantized code is one of a plurality of first quantized codes which are defined on the scale along the first direction, each first quantized code sequence included in the plurality of first quantized codes indicates a first coordinate of the scale in the first direction, the second quantized code is one of a plurality of second quantized codes which are defined on the scale along the second direction, and each second quantized code sequence included in the plurality of second quantized codes indicates a second coordinate of the scale in the second direction, and the first quantized code sequence is generated based on detection of the first number of marks and information of the pairs corresponding to the characteristics, the absolute position of the scale in the first direction is obtained based on the first quantized code sequence, the second quantized code sequence is generated based on detection of the second number of marks and the information of the pairs corresponding to the characteristics, and the absolute position of the scale in the second direction is obtained based on the second quantized code sequence.

A two-dimensional absolute encoder comprising a scale for use in a two-dimensional absolute encoding method, and configured to execute steps in the two-dimensional absolute encoding method, the method obtaining absolute positions in a first direction and a second direction of the scale, wherein, on the scale, a plurality of marks are two-dimensionally arranged with a predetermined space therebetween at a predetermined pitch along the first direction and the second direction, the method comprising steps of:

• detecting a first number of marks arranged in the first direction, and a second number of marks arranged in the second direction;
• and
• obtaining absolute positions of the scale in the first direction and the second direction based on the detected first number of marks and the detected second number of marks, respectively, wherein
• each of the plurality of marks has one of a plurality of characteristics corresponding to pairs of information of a first quantized code and information of a second quantized code, wherein the first quantized code is one of a plurality of first quantized codes which are defined on the scale along the first direction, each first quantized code sequence included in the plurality of first quantized codes indicates a first coordinate of the scale in the first direction, the second quantized code is one of a plurality of second quantized codes which are defined on the scale along the second direction, and each second quantized code sequence included in the plurality of second quantized codes indicates a second coordinate of the scale in the second direction, and
• the first quantized code sequence is generated based on detection of the first number of marks and information of the pairs corresponding to the characteristics, the absolute position of the scale in the first direction is obtained based on the first quantized code sequence, the second quantized code sequence is generated based on detection of the second number of marks and the information of the pairs corresponding to the characteristics, and the absolute position of the scale in the second direction is obtained based on the second quantized code sequence.

A two-dimensional absolute encoder comprising:

• a scale on which a plurality of marks are two-dimensionally arranged with a predetermined space therebetween at a predetermined pitch along a first direction and a second direction;
• a detector configured to detect a first number of marks arranged in the first direction, and to detect a second number of marks arranged in the second direction;
• and
• a processor configured to respectively obtain absolute positions of the scale in the first direction and the second direction based on outputs from the detector,
• wherein each of the plurality of marks has one of characteristics corresponding to pairs of information of a first quantized code for indicating a position of the scale in the first direction and information of a second quantized code for indicating a position of the scale in the second direction, and
• the processor is configured to generate a first code sequence including the first number of the first quantized code based on detection of the first number of marks and information of the characteristics, to obtain an absolute position of the scale in the first direction based on the first code sequence, to generate a second code sequence including the second number of the second quantized code based on detection of the second number of marks and the information of the characteristics, and to obtain an absolute position of the scale in the second direction based on the second code sequence.

A two-dimensional absolute encoding method of obtaining absolute positions in a first direction and a second direction of a scale, wherein, on the scale, a plurality of marks are two-dimensionally arranged with a predetermined space therebetween at a predetermined pitch along the first direction and the second direction, the method comprising steps of:

• detecting a first number of marks arranged in the first direction and a second number of marks arranged in the second direction;
• and
• obtaining absolute positions of the scale in the first direction and the second direction based on the detected first number of marks and the detected second number of marks, respectively,
• wherein
• each of the plurality of marks has one of a plurality of characteristics corresponding to pairs of information of a first quantized code and information of a second quantized code, wherein the first quantized code is one of a plurality of first quantized codes which are defined on the scale along the first direction, each first quantized code sequence included in the plurality of first quantized codes indicates a first coordinate of the scale in the first direction, the second quantized code is one of a plurality of second quantized codes which are defined on the scale along the second direction, and each second quantized code sequence included in the plurality of second quantized codes indicates a second coordinate of the scale in the second direction, and
• the first quantized code sequence is generated based on detection of the first number of marks and information of the characteristics, the absolute position of the scale in the first direction is obtained based on the first quantized code sequence, the second quantized code sequence is generated based on detection of the second number of marks and the information of the characteristics, and the absolute position of the scale in the second direction is obtained based on the second quantized code sequence.

A scale for use in a two-dimensional absolute encoding method, the method obtaining absolute positions in a first direction and a second direction of a scale, wherein, on the scale, a plurality of marks are two-dimensionally arranged with a predetermined space therebetween at a predetermined pitch along the first direction and the second direction, the method comprising steps of:

• detecting a first number of marks arranged in the first direction and a second number of marks arranged in the second direction;
• and
• obtaining absolute positions of the scale in the first direction and the second direction based on the detected first number of marks and the detected second number of marks, respectively,
• wherein
• each of the plurality of marks has one of a plurality of characteristics corresponding to pairs of information of a first quantized code and information of a second quantized code, wherein the first quantized code is one of a plurality of first quantized codes which are defined on the scale along the first direction, each first quantized code sequence included in the plurality of first quantized codes indicates a first coordinate of the scale in the first direction, the second quantized code is one of a plurality of second quantized codes which are defined on the scale along the second direction, and each second quantized code sequence included in the plurality of second quantized codes indicates a second coordinate of the scale in the second direction, and
• the first quantized code sequence is generated based on detection of the first number of marks and information of the characteristics, the absolute position of the scale in the first direction is obtained based on the first quantized code sequence, the second quantized code sequence is generated based on detection of the second number of marks and the information of the characteristics, and the absolute position of the scale in the second direction is obtained based on the second quantized code sequence.

A two-dimensional absolute encoder comprising a scale for use in a two-dimensional absolute encoding method, and configured to execute steps in the two-dimensional absolute encoding method, the method obtaining absolute positions in a first direction and a second direction of the scale, wherein, on the scale, a plurality of marks are two-dimensionally arranged with a predetermined space therebetween at a predetermined pitch along the first direction and the second direction, the method comprising steps of:

• detecting a first number of marks arranged in the first direction and a second number of marks arranged in the second direction;
• and
• obtaining absolute positions of the scale in the first direction and the second direction based on the detected first number of marks and the detected second number of marks, respectively,
• wherein
• each of the plurality of marks has one of a plurality of characteristics corresponding to pairs of information of a first quantized code and information of a second quantized code, wherein the first quantized code is one of a plurality of first quantized codes which are defined on the scale along the first direction, each first quantized code sequence included in the plurality of first quantized codes indicates a first coordinate of the scale in the first direction, the second quantized code is one of a plurality of second quantized codes which are defined on the scale along the second direction, and each second quantized code sequence included in the plurality of second quantized codes indicates a second coordinate of the scale in the second direction, and
• the first quantized code sequence is generated based on detection of the first number of marks and information of the characteristics, the absolute position of the scale in the first direction is obtained based on the first quantized code sequence, the second quantized code sequence is generated based on detection of the second number of marks and the information of the characteristics, and the absolute position of the scale in the second direction is obtained based on the second quantized code sequence.