Optical Mouse Blue Light Filter Off-Surface Detection

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Solution Overview

Problem

Optical mice face challenges in accurately detecting the off-surface condition due to the interference of ambient light, which affects their performance and battery life.

Innovation Solution

The use of a light source emitting light in the blue region of the visible spectrum combined with an optical band pass filter that passes blue light while filtering red and infrared wavelengths, enhancing contrast and improving off-surface detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a broad-spectrum light source is used to illuminate the tracking surface, then sufficient light intensity is provided for motion tracking, but ambient light interference degrades off-surface detection accuracy

Engineering Contradiction:

Improvelight intensity for motion trackingVSAvoidoff-surface detection accuracy

Core Design Contradiction:

Illumination intensityVSMeasurement precision

Solution Approach 1:

The patent changes the wavelength parameter of the light source to blue region (400-490 nm) and introduces an optical band pass filter to selectively transmit only this wavelength range. This parameter change allows the system to maintain sufficient illumination intensity while rejecting ambient light at other wavelengths, thereby improving off-surface detection accuracy without sacrificing motion tracking capability

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The optical band pass filter acts as an intermediary element between the light source and the image sensor. It selectively transmits blue light from the light source while blocking ambient light at other wavelengths, enabling the system to achieve both sufficient illumination for motion tracking and rejection of ambient light interference for accurate off-surface detection

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the light source intensity is increased to improve motion tracking, then tracking performance is enhanced, but power consumption increases

Engineering Contradiction:

Improvemotion tracking performanceVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent changes the wavelength parameter to blue region, which has higher scattering efficiency and provides better contrast for motion tracking. This allows the light source to operate at lower intensity while maintaining reliable tracking performance, thereby reducing power consumption without sacrificing reliability

Inventive Principle:

Principle #35Parameter changes

3Use of energy by moving object

If the light source is dimmed or shut off to preserve battery life during off-surface condition, then power consumption is reduced, but motion tracking cannot be performed

Engineering Contradiction:

Improvebattery lifeVSAvoidmotion tracking capability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent replaces the mechanical/approximate off-surface detection method with an optical field-based detection method using blue light and band pass filter. This substitution enables more accurate and reliable off-surface detection, allowing the system to confidently dim or shut off the light source without compromising tracking capability, thereby extending battery life

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

This configuration provides high-contrast images for motion tracking, reduces power consumption, and improves battery life by minimizing ambient light interference and allowing for more robust tracking features with lower light source intensities.

Implementation Method 1

an optical band pass filter configured to pass the light having the wavelength in or near the blue region of the visible light spectrum emitted by the light source while filtering red and infrared wavelengths

Methodology Applied

Scientific EffectOptical band pass filtering: Filter (optical)

Implementation Method 2

a light source configured to emit light having a wavelength in or near a blue region of a visible light spectrum toward a tracking surface

Methodology Applied

Scientific EffectLight emission: Light

Data Source

PatentUS8847888B2Optical mouse with limited wavelength optics

Publication Date: 2014.09.30 MICROSOFT TECHNOLOGY LICENSING LLC

AI summary

Various embodiments of optical mice are disclosed that facilitate off-surface detection while also providing high-contrast images of a tracking surface. In one embodiment, an optical mouse comprises a light source configured to emit light having a wavelength in or near a blue region of a visible light spectrum toward a tracking surface, an image sensor, and an optical band pass filter configured to pass the light having the wavelength in or near the blue region of the visible light spectrum emitted by the light source while filtering red and infrared wavelengths. Further, the mouse also comprises a controller configured to receive image data from the image sensor and to identify a tracking feature in the image data. The band pass filter prevents ambient light in the filtered wavelengths from reaching the image sensor, and thereby facilitates off-surface detection, while the blue color of the incident light and band pass filter provides a high-contrast image for motion tracking.