Transmissive Optical Encoder Same-Side Waveguide
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Solution Overview
Problem
Transmissive optical encoders face challenges in miniaturization without compromising detection accuracy due to complex configurations and mechanical oscillations affecting optical waveguide alignment, leading to increased manufacturing costs and limited usage.
Innovation Solution
A transmissive optical encoder design with a light emitting element and light receiving element on the same side of the rotatable disk, featuring an optical waveguide that is fixed independently of the disk's rotational movement, utilizing total reflection or mirror reflection within the waveguide, and optionally including optical elements to adjust light direction and enlarged sections to minimize light loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the light emitting element and light receiving element are arranged on opposite sides of the rotatable disk, then the optical system can be simplified, but the encoder occupies a larger space
Solution Approach 1:
The patent transitions from a conventional opposite-side arrangement to a same-side arrangement by utilizing the rotational dimension of the disk. The light emitting element and light receiving element are positioned on the same side of the rotatable disk, with the light path passing through the disk's thickness, thereby achieving compactification without sacrificing optical functionality.
2Volume of moving object
If the optical waveguide is moved together with the mechanically rotating part, then the encoder can be miniaturized, but mechanical oscillation at high speed impairs detection accuracy
Solution Approach 1:
The patent segments the optical system into two independent parts: a stationary optical waveguide and a rotating disk assembly. The waveguide remains fixed while the disk rotates, separating the optical coupling function from the mechanical rotation function. This prevents mechanical oscillation from affecting the optical waveguide's alignment, maintaining detection accuracy while enabling miniaturization.
3Measurement precision
If the projection means forms an equal magnification inverting optical system, then the detection accuracy can be ensured, but the manufacturing cost increases due to complex configuration and precise positioning requirements
Solution Approach 1:
The patent extracts and eliminates the complex projection means from the optical system. Instead of using an equal magnification inverting optical system, the invention directly couples the light emitting element to the light receiving element through the rotating disk, removing unnecessary components and simplifying the overall configuration while maintaining detection accuracy.
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 miniaturization of the optical system, reduces manufacturing costs, and maintains detection accuracy by isolating the optical system from mechanical oscillations, resulting in a compact and cost-effective encoder.
Implementation Method 1
the optical waveguide is configured such that incident light to the optical waveguide is subject to total reflection
Implementation Method 2
the optical waveguide has an internal structure formed from a mirror face such that incident light to the optical waveguide is subject to mirror reflection
Data Source
AI summary
A transmissive optical encoder includes a light emitting element, a light receiving element, a rotatable disk provided with slits and rotatable together with an object of detection, and an optical waveguide having an inlet facing the light emitting element and an outlet facing the light receiving element. The light emitting element and the light receiving element are arranged on the same side in relation to the rotatable disk. The optical waveguide is fixed independently of rotational movement of the rotatable disk.