Optical Encoder with Anisotropic Reflecting Regions for Precision
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Solution Overview
Problem
Traditional rotary sensors are not well-suited for compact electronic devices due to their size and lack of precision in measuring small rotational inputs, such as those found in devices with a small form factor, like wristwatches.
Innovation Solution
An optical encoder with a cylindrical spindle featuring alternating optically-contrasting elements and anisotropic reflecting regions that produce direction-dependent light distributions, allowing for precise measurement of rotational inputs using an optical emitter and detector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional rotary sensors are used, then they can measure rotary motion, but they are too large for compact electronic devices and lack precision for small rotational inputs
Solution Approach 1:
The patent replaces traditional mechanical rotary sensors with an optical encoder system that uses light reflection and detection. The optical encoder includes a light source, code disk with reflective and non-reflective segments, and photodetectors, eliminating the need for bulky mechanical components while achieving higher measurement precision for small rotational inputs
Solution Approach 2:
The patent transitions from mechanical measurement in three-dimensional space to optical measurement using two-dimensional code patterns on the code disk. The reflective and non-reflective segments create optical signals that provide precise rotational measurement without requiring the physical bulk of traditional mechanical sensors
2Reliability
If anisotropic reflecting regions are used, then directional light distribution improves detection reliability, but manufacturing complexity increases
Solution Approach 1:
The patent applies local quality by creating specific regions on the code disk with different optical properties - reflective regions that mirror light and non-reflective regions that absorb or scatter light. These localized optical characteristics enable reliable directional detection while maintaining manufacturability through standard coating and patterning processes
Solution Approach 2:
The patent changes the optical parameters of the code disk surface by applying different coatings or surface treatments to create reflective and non-reflective segments. This allows control over light reflection characteristics without complex manufacturing, using conventional deposition or etching techniques to achieve the desired optical contrast
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
The optical encoder provides improved precision and compactness, enabling reliable detection of rotational movement, direction, speed, and other qualities of rotation, even with dimensional variations, making it suitable for small form factor devices.
Implementation Method 1
the optically contrasting elements may include an array of anisotropic reflecting regions that has a first light distribution for light reflected along a first direction and have a second, wider light distribution along a second direction
Implementation Method 2
the anisotropic reflecting regions may diffuse or spread the light along a direction that corresponds to the length of the feature
Implementation Method 3
the optical sensor includes an optical emitter, such as a light emitting diode
Implementation Method 4
an optical detector, such as a photodiode array
Data Source
AI summary
Embodiments of the present disclosure provide an optical encoder for an electronic device. The optical encoder includes a spindle and an encoded pattern disposed around a circumference of the spindle. The encoded pattern may include one or more surface features that create a direction-dependent reflective region.