Sensor signal processor

• US 7,099,790 B2
• Filed: 10/18/2004
• Issued: 08/29/2006
• Est. Priority Date: 10/22/2003
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Igaki, Masahiko, Atsuta, Akio
• Primary Examiner(s): Nghiem, Michael
• Assistant Examiner(s): KHUU, HIEN DIEU THI
• Application Number:
  US10/968,320
• Publication Number:
  US 20050090998A1
• Time in Patent Office: 680 Days
• Field of Search: 702/117
• US Class Current: 702/117
• CPC Class Codes: G01D 5/24409 Interpolation using memories

Abstract

A sensor signal processor includes a scale having optically or magnetically fine divisions; a detection sensor that moves with respect to the scale and that is provided in association with the divisions of the scale; and a position detecting unit for calculating positional information by using a counter value of digital pulse signals generated from the outputs from the detection sensor and analog signals generated from the outputs from the detection sensor. The sensor signal processor yields the positional information by using both the digital pulse signals and the analog signals.

Claims

1. A system for processing sensor signals comprising:

scaling means for providing a scale having optically or magnetically fine divisions;

detection sensor means for providing movement with respect to the scale and that is provided in association with the divisions of the scale; and

position detecting means for calculating positional information by using a counter value of digital pulse signals generated from the outputs from the detection sensor and analog signals generated from the outputs from the detection sensor,

wherein the sensor signal processor detects relative displacement of the scale and the sensor detection means,

wherein the analog signals are two-phase analog signals that are used to perform division and tan<sup>−

1</sup> calculation for providing the positional information,

wherein the relationship between the two-phase analog signals is determined based on regions in which the division result is within a range having values not more than a predetermined value, and

wherein the counter value is calculated by adding a value given by the tan<sup>−

1</sup> calculation of the division result to the counter value of the digital signals.

2. A sensor signal processor comprising:

a scale having optically or magnetically fine divisions;

a detection sensor that moves with respect to the scale and that is provided in association with the optically or magnetically fine divisions of the scale; and

a position detecting unit for calculating positional information by using a counter value of digital pulse signals generated from the outputs from the detection sensor and analog signals generated from the outputs from the detection sensor,

wherein the sensor signal processor detects relative displacement of the scale and the detection sensor,

wherein the analog signals include a first analog signal and a second analog signal, which are out of phase and on which the positional information is based,

wherein the positional information is calculated by performing division and tan<sup>−

1</sup> operations using the first and second analog signals,

wherein the relationship between the first and second analog signals is determined based on regions in which the division result is within a range having values not more than a predetermined value, and

wherein the counter value is calculated by adding a value given by tan<sup>−

1</sup> calculation of the division result to the counter value of the digital signals.