Rotary Encoder Collinear Optical Path Design
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Solution Overview
Problem
Existing rotary encoders with reflective optical beam paths face challenges in aligning components, leading to complex and costly structures with significant intensity loss, due to the need for multiple structural levels and beam deflection, which complicates positioning and reduces symmetry.
Innovation Solution
A rotary encoder design where the light transmitter and receiver are arranged collinearly with the light passing through a hole in the receiver surface, integrated on an electronic card, allowing for a compact, symmetrical structure with a polarizer rotating relative to the light source, and featuring a polarizer and analyzers to ensure accurate angle measurement without extra components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If beam splitters, mirror systems or similar are used to deflect light and position components centrally, then central alignment of components on an optical axis is achieved, but the structure becomes complicated, expensive, and requires considerable space with significant intensity loss
Solution Approach 1:
The patent removes beam splitters, mirror systems, and other light-deflecting components from the optical path. Instead, the light transmitter and receiver are positioned collinearly with the light passing directly through a hole in the receiver surface, eliminating the need for complex deflecting elements while maintaining central alignment
Solution Approach 2:
The patent transitions from a multi-level structural arrangement (requiring vertical stacking of components at different heights) to a single-plane collinear arrangement where all components lie on the same optical axis, reducing structural complexity and improving symmetry
2Manufacturing precision
If multiple structural levels are used to position components, then central alignment is achieved, but positioning and adjustment becomes complicated and expensive
Solution Approach 1:
The patent eliminates multi-level structural arrangements and the associated complex positioning mechanisms. The collinear configuration allows all components to be positioned on a single plane, dramatically simplifying manufacturing and adjustment processes
Solution Approach 2:
The patent employs asymmetric positioning of the light transmitter and receiver relative to the rotating scale, with both components offset from the optical axis by different amounts. This asymmetric arrangement, combined with the collinear configuration, achieves accurate angle measurement while maintaining structural simplicity
3Manufacturing precision
If beam deflection is used to achieve central alignment, then symmetry is improved, but light intensity is considerably lost
Solution Approach 1:
The patent removes all beam-deflecting elements (beam splitters, mirrors) from the optical path. The light travels directly from the transmitter through the scale to the receiver without any deflection, eliminating intensity losses associated with multiple reflections and transmissions through optical elements
Solution Approach 2:
The patent segments the optical path into distinct functional zones (transmitter region, scale region, receiver region) arranged collinearly, allowing each component to be optimized independently while maintaining overall symmetry and minimizing light intensity loss
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 eliminates asymmetry-related systematic errors, reduces component count, and achieves a compact, efficient structure with minimal intensity loss, enabling precise angle measurement over 360° without the need for additional optical components.
Implementation Method 1
a light transmitter (20) that emits transmitted light (32) in a transmitted light direction
Implementation Method 2
The transmitted light is reflected at the polarizer and passes through one or more polarizing analyzers
Implementation Method 3
The rotary encoder is designed as a polarization encoder and has a polarizer, which rotates relative to the light source
Implementation Method 4
a light receiver (22) with a light-receiving surface (38), the light-receiving surface being arranged in such a way that the transmitted light direction is the surface normal of the light-receiving surface
Data Source
Figure 1
Figure 2
AI summary
The transducer (10) has a transmitting and receiving unit (12) having a light emitter (20) i.e. LED, that emits light in a transmission direction. A light receiver (22) is arranged with a light receiving surface (38) arranged such that light transmission direction corresponds to a direction normal to the light receiving surface. The light receiver receives back-reflected transmission light (32) as receiving light (26). The light emitter is arranged on the light receiving surface facing away from the light receiver, and the transmitted light enters the receiving surface through a hole (42). The light receiver is arranged as a receiver array in CCD or CMOS construction.