Rotatable Light Source Array for Multi-Pitch Optical Encoder Readheads
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Solution Overview
Problem
Existing optical displacement encoders with fixed pitch illumination gratings are not adaptable to different grating pitches, limiting their versatility and requiring non-interchangeable components, which complicates manufacturing and increases costs.
Innovation Solution
An optical encoder design featuring a light source array configured in a 2D grid pattern, allowing for different rotational orientations to accommodate various scale grating pitches, enabling interchangeable components and a more compact, cost-efficient readhead by aligning light sources perpendicular to the measuring axis with adjustable pitches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a fixed pitch illumination grating is used, then the encoder can be manufactured with simple components, but it cannot accommodate different grating pitches and resolutions
Solution Approach 1:
The illumination portion is designed with a light source array that can be rotated to different orientations, allowing the same component to serve multiple functions for different scale grating pitches. By rotating the light source array among predetermined orientations, the encoder can accommodate multiple grating pitches without requiring different illumination components for each pitch, thus achieving universality.
Solution Approach 2:
The light source array is made rotatable relative to the scale grating, transforming a static fixed-pitch system into a dynamic multi-pitch system. The rotation mechanism allows the illumination portion to adapt its configuration based on the required grating pitch, enabling the same physical component to dynamically adjust its effective pitch through rotational positioning.
2Adaptability or versatility
If interchangeable components are implemented for different pitches, then versatility is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
Instead of creating multiple specialized illumination portions for different pitches, the invention uses a single universal illumination portion with a rotatable light source array. This universal component can be configured for different pitches by rotation, eliminating the need for multiple interchangeable parts and reducing device complexity while maintaining versatility.
Solution Approach 2:
The invention merges multiple pitch-specific illumination functions into a single rotatable light source array assembly. By combining what would otherwise be separate interchangeable components into one unified rotatable structure, the system reduces the number of parts, simplifies assembly, and lowers manufacturing costs while preserving the ability to accommodate different grating pitches.
3Adaptability or versatility
If a rotatable light source array is used, then multiple grating pitches can be accommodated, but the illumination portion complexity increases
Solution Approach 1:
The light source array incorporates a rotation mechanism that allows dynamic reconfiguration between different orientations. This dynamic capability enables the same physical hardware to adapt to multiple grating pitches without requiring complex electronic control or multiple static configurations, achieving multi-pitch capability through mechanical rotation.
Solution Approach 2:
The invention adds a rotational dimension to the traditionally planar light source array configuration. By introducing rotation as an additional degree of freedom, the system can achieve multiple pitch configurations without increasing the planar footprint or requiring multiple separate components, thus managing complexity through spatial reconfiguration.
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 design allows for interchangeable components and a more compact readhead, reducing manufacturing complexity and costs while supporting multiple grating pitches and resolutions, enhancing the encoder's versatility and efficiency.
Implementation Method 1
a light source array, individual sources of which are arranged in an approximately planar two-dimensional (2D) grid pattern
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A light source array (265) used in illumination portions for optical encoders comprising an illumination portion (260), a scale grating (210) extending along a measuring direction (82) and receiving light (231) from the illumination portion (260), and a detector configuration (225). The light source array (225) comprises individual sources (265n) arranged in a grid pattern and coinciding with two transverse sets of parallel grid pattern lines (GPL1, GPL2) that have two different grid line pitches (P1, P2) between their parallel lines. Different instances of the light source array (265) may be mounted with different rotational orientations about an axis normal to the grid pattern, for use in different illumination portions adapted for use with respective scale gratings (210) having different grating pitches (SGP1, SGP2) along the measuring axis direction. By using the different respective rotational orientations, the individual sources (265n) are aligned along respective illumination source lines (ISL1, ISL2) that are spaced apart by different respective illumination source line pitches (IP1, IP2) along the measuring axis direction (82).