Optical Engine Beam Shaping for Hover-Mode Navigation
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Solution Overview
Problem
Optical mice experience a decrease in light utilization efficiency when operating in a hover mode due to reduced light power reflection from non-mirror surfaces as the distance from the work surface increases, leading to degraded performance.
Innovation Solution
An optical engine that generates a semi-collimated illumination beam with a cross-section that maintains a consistent size in one direction while reducing the size in a perpendicular direction, enhancing light concentration near the light sensor's sensing region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the working gap between the optical mouse and the work surface is increased to enable hover mode operation, then the device can operate without direct contact with the surface, but the light power reflected by the work surface to the light sensor becomes lower, decreasing light utilization efficiency
Solution Approach 1:
The patent applies local quality by creating different beam characteristics in different spatial directions. The illumination beam is shaped to have different cross-sectional dimensions in the first transverse direction versus the second transverse direction, with the beam being narrower in one direction to concentrate light power while maintaining adequate coverage in the other direction, thereby improving light utilization efficiency at increased working gaps
Solution Approach 2:
The patent changes the geometric parameters of the illumination beam by using optical elements (such as cylindrical lenses or aspherical lenses) to transform the beam cross-section. The beam cross-section is modified to have different sizes in different transverse directions, creating a semi-collimated or focused beam that maintains higher light power density at larger working gaps, thus resolving the contradiction between hover mode capability and light utilization efficiency
2Adaptability or versatility
If the working gap is increased beyond direct contact operation, then the device can perform hover mode functions, but the detected light power degrades with increasing working gap distance
Solution Approach 1:
The illumination beam is designed with non-uniform cross-sectional dimensions, being narrower in one transverse direction to concentrate light power and maintain higher intensity at increased distances, while maintaining adequate width in the other direction for sufficient surface coverage, thereby improving reliability of detected light power in hover mode
Solution Approach 2:
The patent introduces asymmetry in the beam cross-section by using optical elements that create different beam widths in orthogonal transverse directions. This asymmetric beam shaping allows the light to be more concentrated in the direction where distance degradation is most critical, maintaining reliable light detection at larger working gaps while enabling hover mode operation
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
Improves light utilization efficiency by maintaining consistent light power reception at varying working gaps, ensuring effective operation in hover mode.
Implementation Method 1
The light source is configured to generate an illumination beam, which has a cross-section passing through a first lens of the navigation device
Data Source
AI summary
There is provided a navigation device including a light source, a light guide and a light sensor. The navigation device is operated relative to a work surface. The light source generates an illumination beam passing through the light guide to generate an illuminated area on the work surface. The light sensor receives reflected light from the illuminated area via the light guide. When a working gap between the navigation device and the work surface is increased, a first size of the illuminated area in a first direction is substantially identical to a first initial size of the illumination beam in the first direction after just leaving the light guide, and a second size of the illuminated area in a second direction is smaller than a second initial size of the illumination beam in the second direction after just leaving the light guide.