Optical Encoder with Combined Incremental and Absolute Sensors

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Solution Overview

Problem

Conventional incremental encoders require resetting the origin every time they are turned on, while absolute encoders have limited resolution due to the number of bits used for encoding, posing challenges in precise positioning measurement in precision machinery.

Innovation Solution

An optical positioning measurement device incorporating a light source module, encoder module, and sensor module with both incremental and absolute code portions, allowing for precise incremental position measurement without the need for constant origin resetting and enhancing resolution through differential quadrature signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If incremental encoders are used to measure positional variations, then the device can operate without absolute position confirmation, but the origin must be reset every time the machinery is turned on

Engineering Contradiction:

Improveoperation continuityVSAvoidorigin reset requirement

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent combines incremental code patterns and absolute code patterns on the same encoder disk. The incremental code portion provides continuous position measurement while the absolute code portion provides origin confirmation, merging the advantages of both encoding types to eliminate the need for frequent origin resets while maintaining operation continuity

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The encoder disk is segmented into multiple functional portions: an absolute code portion with absolute code patterns and an incremental code portion with incremental code patterns. This segmentation allows different sensing units to read different code types simultaneously, resolving the contradiction between continuous operation and origin reliability

Inventive Principle:

Principle #1Segmentation

2Reliability

If absolute encoders are used to confirm absolute position, then the origin does not need resetting, but the resolution is limited by the number of bits used for encoding

Engineering Contradiction:

Improveabsolute position confirmationVSAvoidpositioning resolution

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent merges absolute encoding and incremental encoding on the same encoder disk. The absolute code portion provides reliable absolute position confirmation while the incremental code portion with its finer code patterns provides high resolution positioning, combining both reliability and precision simultaneously

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent adds a dimensional aspect by incorporating two types of code patterns (absolute and incremental) with different resolution characteristics on the same encoder disk. This allows the system to access both coarse absolute position information and fine incremental position information, effectively increasing the overall measurement precision while maintaining reliability

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Measurement precision

If the encoder disk includes multiple code portions with different code pattern densities, then positioning resolution is enhanced, but the device complexity increases

Engineering Contradiction:

Improvepositioning resolutionVSAvoidencoder structure

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges multiple code portions (absolute code portion and incremental code portion) on a single encoder disk with a unified structure. Both code types are read by sensing units positioned on the same disk, avoiding the need for separate encoder disks or complex multi-component systems, thus enhancing resolution while controlling device complexity

Inventive Principle:

Principle #5Merging (Combining)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The device achieves precise positioning measurements with enhanced resolution by combining incremental and absolute encoding, eliminating the need for frequent origin resets and improving decoding accuracy.

Implementation Method 1

The light source module is operable to emit light

Methodology Applied

Scientific EffectLight emission: Light Emitting Diode

Implementation Method 2

The sensor module is disposed to receive light provided by the light source module via the encoder module, and is configured to output electric signal relating to luminous flux of light received thereby

Methodology Applied

Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentUS10921163B2Optical encoder with incremental and absolute code sensors and defining distance between geometric centers of adjacent photosensors of an incremental code sensor

Publication Date: 2021.02.16 HIWIN MIKROSYST

AI summary

An optical positioning measurement device includes a light source module operable to emit light, an encoder module and a sensor module. The sensor module is configured to output electric signals relating to luminous flux of light received thereby via the encoder module. The encoder module having a first incremental code portion, a second incremental code portion and an absolute code portion. The first incremental code portion includes multiple first incremental code patterns that are equally distributed. The second incremental code portion includes multiple second incremental code patterns that are equally distributed. The second incremental code patterns are arranged more loosely than the first incremental code patterns.