Patent ID: 8436293

Claim:
An optical encoder comprising: a light source configured to generate at least one beam of light; an encoder member positioned to receive said at least one beam of light from said light source, said encoder member including: a first optical track including a plurality of first optical track segments, each of said first optical track segments including one or more first diffractive optical regions configured to manipulate said at least one beam of light to produce at least one first diffracted beam of light; and a second optical track including a plurality of second optical track segments, each of said second optical track segments including one or more second diffractive optical regions configured to manipulate said beam of light to produce at least one second diffracted beam of light; wherein said first and second optical tracks are configured such that the periodicity of consecutive identical first diffractive optical regions of said first optical track is different than the periodicity of consecutive identical second diffractive optical regions of said second optical track and wherein at least one particular first diffractive optical region is positioned on the first optical track between the consecutive identical first diffractive optical regions and at least one particular second diffractive optical region is positioned on the second optical track between the consecutive identical second diffractive optical regions, the particular first diffractive optical region having a different diffractive property than the consecutive identical first diffractive optical regions, the particular second diffractive optical region having a different diffractive property than the consecutive identical second diffractive optical regions; and a plurality of photodetectors configured to receive said at least first diffracted beam of light and said at least one second diffracted beam to produce electrical signals, said electrical signals being related to displacement information being measured.