Avago Technologies General IP (singapore) Pte. Ltd.

Avago Technologies Ecbu IP (singapore) Pte. Ltd.

Kean Foong Ng

Yee Loong Chin

Hock Aun Tan

Weng Fei Wong

Chee Foo Lum

Sze Kuang Lee

Kok Hing Fo

Wee Jin Yeap

Toshiya Hataguchi

Siang Leong Foo

Moon Leong Low

Randeep Singh A/l Amarjit

Randeep Singh A/l Amarjit Singh

An encoder having a code scale, an illumination system, and a plurality of photodetectors is disclosed. The code scale has a plurality of tracks that are illuminated by the illumination system. Each photodetector receives light from a corresponding one of the tracks and generates a signal indicative of a quantity of light received from that track. Each photodetector is limited to detecting light in a band of wavelengths corresponding to that track. Each track generates light in a band of wavelengths corresponding to that track, and the band of wavelengths corresponding to one of the tracks is different from the band of wavelengths corresponding to the tracks that are next to that track. The tracks can include alternating reflective and absorptive stripes, alternating transmissive and reflective stripes, or alternating luminescent and absorptive stripes.

Absolute encoder utilizing light of different wavelengths to reduce cross talk

Absolute encoder utilizing light of different wavelengths to reduce cross-talk

An optical encoder includes a code strip having a first side, a second side, a first track comprising indicia thereon, and a second track comprising indicia thereon. The code strip is moveable along a displacement path with respect to the optical encoder. A light source positioned on the first side of the code strip directs light toward the code strip. A first detector element is positioned on the second side of the code strip and is generally aligned with the first track of the code strip. A second detector element is positioned on the second side of the code strip and is generally aligned with the second track of the code strip. The second detector element is also positioned so that the second detector element is located a spaced distance along the displacement path from the first detector element.

Optical encoder

An interpolating detector for generating a position signal indicating a change in the relative position of a code pattern that includes alternating light and dark stripes is disclosed. The interpolating detector includes a photodiode array, an interpolation function generator, a detector function generator, and a cross-point detector. The photodiode array includes a plurality of sets of photodetectors that generate sinusoidal signals having different amplitudes and phases. The interpolation function generator generates first and second interpolation functions, I(x)=f1 cos(x) and I(x)=f2 sin(x), respectively, from the photodiode signals. The detector function generator generates 4 detector signals, D(x)-D(x), from the photodiode signals. The cross-point detector generates a transition signal when I(x) crosses Dor Dor when I(x) crosses Dor D. The photodiodes have active areas having a shape such that the x values at which the interpolation signals cross the detector signals occur at integer multiples of (2&#x3c0;/m) for a fixed m value.

Encoder interpolation apparatus

A Low-Cost Absolute Linear Optical Encoder ('LALOE') for determining the absolute position of a read-head within the LALOE relative to a codestrip is disclosed. The LALOE may include an emitter module within the read-head, the emitter module having a plurality of light sources arranged in an light source pattern and a 90&#xb0; Out-Of-Phase light source; and a detector module within the read-head, the detector module having a plurality of photo-detectors arranged in a photo-detector pattern corresponding to the light source pattern and a 90&#xb0; Out-Of-Phase photo-detector corresponding to the 90&#xb0; Out-Of-Phase light source.

Low-cost absolute linear optical encoder

Growing community of inventors

Penang, Malaysia

Kean Foong Ng