Optical Mouse Sensor Integration Time Control
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Solution Overview
Problem
Optical pointing devices face a trade-off between tracking speed and signal-to-noise ratio (SNR) on different surface types, with darker surfaces requiring more light and longer integration times, leading to increased power consumption and decreased SNR on lighter surfaces.
Innovation Solution
Implementing an integration stop control algorithm that compares output signal integration levels with multiple reference levels to optimize integration time, allowing for faster tracking speeds on darker surfaces and improved SNR on lighter surfaces by adjusting the integration period and pixel gain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If integration time is increased to improve tracking quality on dark surfaces, then signal-to-noise ratio is improved, but tracking speed decreases
Solution Approach 1:
The patent implements dynamic adjustment of integration time based on real-time surface brightness detection. The system transitions from static integration time to adaptive integration time, where the integration period is automatically extended for dark surfaces and reduced for light surfaces, resolving the speed-precision tradeoff through dynamic parameter optimization
Solution Approach 2:
The patent changes the integration time parameter adaptively based on surface characteristics. By detecting surface brightness and adjusting the integration period accordingly, the system optimizes the signal-to-noise ratio on dark surfaces while maintaining high tracking speed on light surfaces, effectively resolving the contradiction between measurement precision and speed
2Measurement precision
If integration time is increased to improve tracking quality on dark surfaces, then signal-to-noise ratio is improved, but power consumption increases
Solution Approach 1:
The patent dynamically adjusts the integration time parameter based on surface brightness detection. On light surfaces, a shorter integration time reduces power consumption while maintaining adequate signal quality. On dark surfaces, the integration time is extended only when necessary to achieve sufficient signal-to-noise ratio, optimizing the energy-precision tradeoff
Solution Approach 2:
The system transitions from fixed integration time to adaptive integration time, where the integration period is dynamically adjusted based on real-time surface characteristics. This dynamic approach reduces unnecessary power consumption on light surfaces while ensuring adequate signal quality on dark surfaces
3Measurement precision
If light source power is increased to improve detection on dark surfaces, then tracking quality is improved, but power consumption increases
Solution Approach 1:
The patent adjusts multiple parameters including light source power and integration time based on surface brightness detection. On light surfaces, lower light source power is used to reduce consumption. On dark surfaces, the system increases light source power and/or integration time only when necessary to maintain tracking quality, optimizing the energy-quality tradeoff
Solution Approach 2:
The system implements dynamic adjustment of light source power based on real-time surface characteristics. This transitions the system from static high power operation to adaptive power management, reducing energy consumption on light surfaces while ensuring adequate illumination and tracking quality on dark surfaces
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 approach effectively balances tracking speed and quality by optimizing SNR for given speed requirements, enhancing performance on both light and dark surfaces while minimizing power consumption.
Implementation Method 1
a photodetector device having at least one photosensitive element responsive to radiation reflected from the illuminated surface portion
Data Source
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AI summary
A method for operating an optical sensing device having a light source and a photodetector device with at least one photosensitive element, said method comprising the steps of: (i) illuminating a surface portion with radiation by means of said light source; (ii) detecting radiation reflected from the illuminated surface portion with said at least one photosensitive element; (iii)while said surface portion is being illuminated, integrating an output signal of said at least one photosensitive element over time; (iv)comparing the output signal integration level with a first integration reference level during integration; (v) interrupting said integration step (iii) if said output signal integration level has reached said first integration reference level, or getting back to comparison step (iv) until a first integration period has elapsed if said output signal integration level has not reached said first integration reference level, and wherein said method further comprises the steps of: (vi) comparing said output signal integration level with a second integration reference level smaller than said first integration reference level, after said first integration period has elapsed; (vii) interrupting said integration step (iii), if said output signal integration level has reached at least said second integration reference level.