Speckle Navigation Using Integrated Laser and Sensor Subsystem
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Solution Overview
Problem
Existing optical mice are complex, multi-component devices prone to inaccuracy and malfunction due to dirt accumulation and mechanical wear, with high image processing requirements and low optical efficiency.
Innovation Solution
A laser positioning device with a planar substrate integrating a coherent light source and sensor array, using a collimating lens to form a collimated illumination beam that generates a speckle pattern for accurate movement tracking without additional optics, reducing component count and manufacturing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate components (light source, beam deviator, sensor array, imaging optics) are used, then functional versatility is improved, but device complexity increases
Solution Approach 1:
The patent integrates the light source, beam deviator, sensor array, and imaging optics into a single integrated circuit substrate. This merging of previously separate components reduces device complexity while maintaining all necessary functions for optical mouse operation.
Solution Approach 2:
The integrated circuit substrate serves multiple functions simultaneously: it acts as the structural base, mounts the light source and sensor array, provides the beam deviator optics, and houses the signal processing circuitry. This multi-functionality approach resolves the contradiction by consolidating diverse functions into a unified platform.
2Ease of operation
If mechanical elements (rotating ball, shaft encoders) are used, then ease of operation is improved, but reliability deteriorates due to dirt accumulation and wear
Solution Approach 1:
The patent replaces the mechanical ball-and-encoder system with an optical sensing system. A light source illuminates the surface, and a sensor array detects motion through optical flow analysis. This substitution eliminates mechanical contact points that accumulate dirt and experience wear, thereby improving reliability while maintaining ease of operation.
3Measurement precision
If grazing incidence illumination is used, then measurement precision is improved, but optical efficiency deteriorates
Solution Approach 1:
The patent modifies the illumination geometry parameter from grazing incidence to near-normal incidence. This parameter change improves optical efficiency by reducing reflection losses and increasing light penetration into the surface texture, while the sensor array and processing algorithms are designed to maintain measurement precision through alternative optical flow detection methods.
4Measurement precision
If two-dimensional CMOS detector with grazing incidence illumination is used, then measurement precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent combines the light source, beam deviator, sensor array, and signal processing circuitry into a single integrated circuit package. This integration dramatically simplifies manufacturing compared to assembling multiple discrete components, while the near-normal incidence illumination approach uses more conventional optical paths that are easier to manufacture than grazing incidence systems.
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 solution provides a compact, low-cost, and accurate optical navigation system with simplified signal processing, capable of tracking movement with high precision and robustness against dirt accumulation, while maintaining ease of manufacturing and reduced component count.
Implementation Method 1
a collimating lens formed within a transparent encapsulant layer
Implementation Method 2
Light from a coherent source scattered off of a rough surface generates a random intensity distribution of light known as speckle
Implementation Method 3
a sensor array and associated circuitry configured on the planar substrate
Data Source
AI summary
One embodiment relates to a laser positioning device for sensing relative movement between a data input device and a surface by determining displacement of image features in a succession of images of the surface. The device forms a single integrated package, which includes a planar substrate and a transparent encapsulant that also embodies a collimating lens. Both a coherent light source and a sensor array and associated circuitry are configured on the planar substrate. Another embodiment relates to a method of sensing relative movement between a data input device and a surface. Coherent light is emitted from a laser and collimated so as to form a collimated illumination beam with a predetermined diameter, D, and a substantially uniform phase front. A speckle pattern is generated by impingement of the collimated illumination beam on the surface and detected by a sensor array. Other embodiments are also disclosed.