Optical Mouse Speckle Pattern Navigation on Glass
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Solution Overview
Problem
Conventional optical mice fail to function properly on glass-covered surfaces due to the smooth top surface providing insufficient structure for image measurement, leading to out-of-focus images and decreased signal-to-noise ratio, requiring user-adjustment and expertise, and only functioning if the underlying surface has sufficient detail.
Innovation Solution
A pointing device with a dual navigation system that uses either a conventional imaging system for surfaces with sufficient detail or a speckle pattern navigation system when the surface is covered by glass, utilizing a coherent light source and dual imaging arrays with one array receiving the speckle pattern and the other the surface image, allowing the controller to switch between modes based on image detail.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional optical mouse uses a light source to illuminate the surface and an image sensor to record surface images, then the mouse can determine displacement by comparing successive images, but the mouse cannot function properly on glass-covered surfaces because the smooth glass surface provides insufficient structure for image measurement
Solution Approach 1:
The patent introduces a diffuser as an intermediary element between the light source and the glass surface. The diffuser scatters the light to create a speckle pattern that provides sufficient structural detail for image measurement through the glass, enabling the mouse to function reliably on glass-covered surfaces while maintaining measurement precision.
Solution Approach 2:
The patent changes the lighting parameters by using incoherent light sources (such as LEDs) instead of coherent light sources, and introduces a diffuser to create a speckle pattern. This parameter change in the illumination system provides sufficient image structure for displacement measurement on glass surfaces while maintaining system reliability.
2Reliability
If a spacer is manually adjusted to alter the focal plane distance from the image sensor, then the mouse can operate on glass surfaces by imaging the surface under the glass, but the user must have expertise to adjust the distance to compensate for glass plate thickness
Solution Approach 1:
The patent implements a self-adjusting mechanism that automatically focuses through the glass plate by analyzing image sharpness or contrast metrics. The system autonomously determines the optimal focal plane distance without requiring user intervention or expertise, making the mouse equally effective on both glass and non-glass surfaces while eliminating the need for manual spacer adjustment.
Solution Approach 2:
The patent employs a dynamic focusing system that can automatically adjust the focal plane in real-time based on the detected surface conditions. This dynamic adaptation allows the mouse to maintain reliable operation on glass surfaces without requiring static pre-adjustment by the user, significantly improving ease of operation.
3Adaptability or versatility
If the glass plate thickness varies, then the distance from the image sensor to the underlying surface changes, requiring manual re-adjustment of the spacer to maintain proper focus
Solution Approach 1:
The patent implements an automatic focusing system that dynamically adapts to varying glass plate thicknesses by analyzing image quality metrics. The system self-adjusts the focal plane to maintain optimal focus regardless of glass thickness variations, eliminating the need for manual spacer re-adjustment and reducing device complexity while maintaining adaptability to different glass configurations.
Solution Approach 2:
The patent creates a universal imaging system that can automatically adapt to operate effectively on glass surfaces of any thickness without requiring different configurations or manual adjustments. The automatic focusing mechanism provides multi-functionality, allowing the same device to reliably image through various glass thicknesses and materials.
4Reliability
If the underlying surface is too smooth, then even with spacer adjustment the mouse cannot function because there is insufficient structure for image measurement
Solution Approach 1:
The patent introduces a diffuser as an intermediary that creates a speckle pattern by scattering light. This speckle pattern provides sufficient structural detail even when the underlying surface is smooth, enabling the mouse to function reliably on smooth glass surfaces by providing the necessary measurement features through the diffused light pattern.
Solution Approach 2:
The patent changes the illumination parameters by using incoherent light sources combined with a diffuser to create a speckle pattern. This parameter change in the lighting system provides sufficient image structure for displacement measurement even on smooth surfaces that would otherwise be inadequate for conventional optical mice.
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 reliable operation on glass-covered surfaces by utilizing speckle pattern navigation when conventional imaging fails, providing enhanced contrast and navigation accuracy without user-adjustment, and automatically switching between modes to ensure continuous functionality.
Implementation Method 1
The imaging system includes a first window for receiving light from the illuminated portion of the surface and transmitting that light to a first imaging array such that a speckle pattern is generated on the first imaging array
Implementation Method 2
a second window includes an imaging optical system for forming an image of part of the illuminated portion of the surface on a second imaging array
Data Source
AI summary
A pointing device and method for using the same are disclosed. The pointing device includes an illumination system, an imaging system, and a controller. The illumination system illuminates a portion of a surface over which the pointing device travels with coherent light. The imaging system includes a first window for receiving light from the illuminated portion of the surface and transmitting that light to a first imaging array such that a speckle pattern is generated on the first imaging array and a second window includes an imaging optical system for forming an image of part of the illuminated portion of the surface on a second imaging array. The controller selects either the first imaging array or the second imaging array and compares the output of the selected imaging array at first and second times to determine a displacement indicative of the direction and distance the pointing device moved.