Optical Encoder Crown Assembly Lens-Free Design
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Solution Overview
Problem
Conventional optical encoders face challenges in achieving high accuracy and microminiaturization due to the need for optical lenses to focus light beams, which increases device size and limits the detection of rotational movements and brightness variations.
Innovation Solution
An optical encoder design featuring a displacement generating unit with a movable axle body and a light-emitting unit providing a light beam with a low divergence angle, reducing scattering and eliminating the need for optical lenses, while incorporating an optical navigation integrated circuit to calculate relative displacements and detect rotational movements and brightness variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical lenses are used to focus the light beam, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent removes the optical lens from the conventional optical encoder structure. The light-emitting unit directly emits light without requiring a lens for focusing, thereby eliminating the component that increases device size while maintaining measurement capability through alternative means.
Solution Approach 2:
The patent replaces the optical focusing mechanism (lens) with an electronic/image processing approach. The sensing array captures images and the system calculates displacement through image comparison, substituting optical focusing with computational image analysis to achieve the same measurement precision without the physical lens.
2Measurement precision
If optical lenses are used to focus the reflected light beam, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent removes the second optical lens that would be disposed on the sensing array to focus reflected light. Instead, the system relies on the sensing array's direct capture capability combined with image processing to achieve clear images and accurate displacement measurement without additional optical focusing components.
Solution Approach 2:
The patent replaces optical focusing of reflected light with electronic image processing. The sensing array captures reflected light images directly, and the system uses image comparison algorithms to calculate displacement, substituting the mechanical/optical focusing system with an electronic computational approach.
3Measurement precision
If the light beam has high intensity, then measurement precision is improved, but loss of substance increases
Solution Approach 1:
The patent replaces reliance on high-intensity focused light with an image processing approach. The sensing array captures images using the available reflected light, and the system calculates displacement through image comparison, eliminating the need to increase light intensity and thereby reducing light scattering losses.
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
Enables accurate tracking of rotational movements and detection of brightness variations without increasing device size, making it suitable for use in wearable devices like smart watches, with the ability to output motion data and interrupt signals as needed.
Implementation Method 1
The light beam has a divergence angle within a range so as to reduce scattering
Implementation Method 2
receives at least a portion of reflected light beam reflected by the working surface
Data Source
AI summary
An optical encoder has a displacement generating unit, a light-emitting unit and an optical navigation integrated circuit. The displacement generating unit has an axle body movable along a central axial line thereof. The axle body has a free end with a diameter larger than a part of the axle body and a planar working surface formed on the free end. The light-emitting unit is configured for operatively providing a light beam to irradiate the working surface of the displacement generating unit. The light beam has a divergence angle within a range to reduce scattering. The optical navigation integrated circuit receives the reflected light beam reflected by the working surface, and calculates a relative displacement between the optical navigation integrated circuit and the working surface.