Optical Encoder for Dual Shaft Motion Sensing
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Solution Overview
Problem
Existing devices that incorporate rotatable and translatable input devices lack an effective method to sense both rotational and translational movements of the input device.
Innovation Solution
The implementation of an optical sensing system that utilizes an optical encoder pattern around the circumference of a shaft, combined with an optical emitter and a two-dimensional array of pixels in an optical receiver, to detect and track both translational and rotational movements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional sensing methods are used for rotatable and translatable input devices, then the device structure remains simple, but the ability to sense both rotational and translational movements simultaneously is lacking
Solution Approach 1:
The patent combines rotational and translational sensing capabilities into a single optical encoder system. The encoder pattern is disposed on the shaft such that it can detect both rotational position and axial translation simultaneously, eliminating the need for separate sensing mechanisms for each type of movement.
Solution Approach 2:
The optical encoder pattern serves multiple functions: it detects rotational position, determines rotational direction, and measures axial translation. This multi-functional approach allows a single component to provide comprehensive movement sensing for both rotational and translational operations of the input device.
2Measurement precision
If multiple separate sensing systems are used for rotation and translation, then each movement type can be detected accurately, but the assembly size and cost increase
Solution Approach 1:
The patent merges rotational and translational sensing into a single optical encoder assembly. The encoder pattern on the shaft and the corresponding optical sensor can simultaneously measure both types of movement, reducing the overall assembly size compared to using separate sensing systems for each movement type.
3Measurement precision
If multiple separate sensing systems are used for rotation and translation, then each movement type can be detected accurately, but the power consumption increases
Solution Approach 1:
The patent combines rotational and translational sensing into a single optical system that uses one light source and one sensor assembly. This eliminates the need for multiple independent sensing systems, thereby reducing overall power consumption while maintaining accurate detection of both rotational and translational movements.
4Adaptability or versatility
If complex sensing mechanisms are used to detect both movements, then sensing capability is improved, but tolerance to alignment and process variations decreases
Solution Approach 1:
The patent uses a two-dimensional optical sensor array to detect movements in multiple dimensions simultaneously. The sensor array can resolve the irradiance pattern position in both radial and axial directions, providing robust detection that is less sensitive to alignment variations and manufacturing tolerances.
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
This solution enables simultaneous detection of both translational and rotational movements with improved tolerance to alignment and process variations, reduced assembly size and cost, lower power consumption, and enhanced radio frequency immunity.
Implementation Method 1
The optical receiver may be configured to receive reflections of the emitted electromagnetic radiation from the optical encoder pattern and generate an irradiance pattern in response to the reflections
Implementation Method 2
The optical encoder pattern may include a series of polygon facets about the circumference and a one-dimensional substantially retroreflective feature parallel to the axis of rotation
Data Source
AI summary
An assembly includes a rotatable and translatable input device having an axis of rotation, a circumference about the axis of rotation, and an optical encoder pattern disposed around the circumference. The optical encoder pattern includes a series of polygon facets about the circumference and a one-dimensional substantially retroreflective feature parallel to the axis of rotation. The assembly further includes an optical emitter configured to emit electromagnetic radiation toward the optical encoder pattern, and an optical receiver including a two-dimensional array of pixels. The optical receiver is configured to receive reflections of the emitted electromagnetic radiation from the optical encoder pattern and generate an irradiance pattern in response to the reflections. The optical emitter and the optical receiver are disposed along a sensing axis orthogonal to the axis of rotation.