Avago Technologies Ecbu IP (singapore) Pte. Ltd.

Avago Technologies General IP (singapore) Pte. Ltd.

Chung Min Thor

Gim Eng Chew

Mei Yee Ng

Boon Keat Tan

Kheng Hin Toh

Lee Ling Teh

Saidan Saiful Bahari

Tengku Norazman Bin Tengku Abd Aziz

Weng Chong Sam

Jlin Cheang Cheong

Chee Wai Ng

Disclosed are various embodiments of circuitry and methods to compensate for variations in hysteresis associated with the comparators of an interpolation circuit in a single track optical encoder. Such variations in hysteresis may be minimized or eliminated by providing appropriately configured resistor ladder circuits to condition the inputs to the comparators, or by programming or trimming resistors in positive feedback loops of the comparators. The single track optical encoder configurations disclosed herein permit very high resolution reflective optical encoders in small packages to be provided. Methods of making and using such optical encoders are also disclosed.

Hysteresis-compensating interpolation circuits in optical encoders

Disclosed are various embodiments of a single track reflective optical encoder featuring current amplifiers disposed in the signal generating circuit thereof. Voltage amplifiers and their associated feedback resistors are eliminated in the various embodiments disclosed herein, resulting in decreased die size and improved encoder signal accuracy and performance, especially at high speeds The single track optical encoder configurations disclosed herein permit very high resolution reflective optical encoders in small packages to be provided. Methods of making and using such optical encoders are also disclosed.

High resolution, high speed, miniaturized optical encoder

Disclosed are various embodiments of a reflective optical encoder having at least three channels&#x2014;two data channels and one index channel&#x2014;disposed along a common axis or single track. The single track configuration disclosed herein permits very high resolution reflective optical encoders in small packages to be provided. In addition, the single track configuration reduces problems with misalignment between code scales and light detectors, permits relatively simple electronic circuitry to be used to process outputs, and reduces manufacturing, assembly, integrated circuit and encoder costs. Methods of making and using such optical encoders are also disclosed.

Single track optical encoder

Disclosed are various embodiments of a single track reflective optical encoder featuring increased spatial resolution, reduced cross-talk between adjoining photodiodes, and increased amplitude output signals from individual photodiodes. With respect to prior art single track optical encoders, some photodiodes are removed from a photodiode array, while nevertheless maintaining appropriate phase relationships between pairs of A and A\, and B and B\, photodiodes. Such a configuration of photodiodes results in increased inter-photodiode spacing, and thereby permits spatial resolution to be increased while boosting current outputs from individual photodiodes. The single track optical encoder configurations disclosed herein permit very high resolution reflective optical encoders in small packages to be provided. In addition, the single track configuration reduces problems with misalignment between code scales and light detectors, permits relatively simple electronic circuitry to be used to process outputs, and reduces manufacturing, assembly, integrated circuit and encoder costs. Methods of making and using such optical encoders are also disclosed.

High resolution single track optical encoder

Disclosed are various embodiments of pulse generation and automatic gain control ('AGC') circuits and corresponding methods that are especially well suited for use in motion encoding systems. Analog output signals provided by a motion encoder serve as inputs to the pulse generation circuit, where peaks, valleys and/or crosspoints corresponding to such analog signals are first detected and then employed to generate output pulses corresponding thereto. These output pulses are next provided to an AGC circuit as self-generated clock signals which control the time windows over which the analog signals of the motion encoder are sampled and processed by the AGC circuit so as to adjust the gains applied to such analog signals.

Automatic gain control for motion encoder signals

According to one embodiment, there is provided a device and method for correcting code wheel misalignment which employs upper and lower code wheel misalignment photodetectors positioned above and below at least first and second motion detection photodetectors. According to other embodiments, there are provided a device and method for automatically setting the gain of an output circuit in an optical encoder. Still further embodiments of optical encoders combine the code wheel misalignment and automatic gain control features of the invention.

Optical encoder with code wheel misalignment detection and automatic gain control

An optical encoder includes a coding element having a track with a track pattern that comprises multiple optically distinguishable sections. The optical encoder compares photodetector outputs with transition-specific thresholds that correspond to transitions between the optically distinguishable sections of the track. The comparisons are used to determine when the transition between two optically distinguishable sections of the track has passed the photodetector. Knowledge of the transition between two optically distinguishable sections is then translated into digital position information.

Multi-bit absolute position optical encoder with reduced number of tracks

The color of a surface is determined by tracking the position of the surface using grayscale image sensing and then using captured grayscale image information, position information, and grayscale-to-color conversion information to determine color. In one embodiment, the technique requires establishing grayscale-to-color conversion information and a relationship between position and the grayscale-to-color conversion information. A calibration pattern is printed on a piece of paper and the surface of the paper is illuminated. Grayscale image information and position information related to the surface is generated in response to the illumination. Color-specific portions of the grayscale-to-color conversion information that are to be used in color determination are selected based on the position information. Grayscale image information related to the calibration pattern is then compared to the selected color-specific portions of the grayscale-to-color conversion information to determine the color of the calibration pattern.

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Riduzan, Malaysia

Chung Min Thor