Optical Displacement Detection Adaptive Lighting Control
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Solution Overview
Problem
Conventional optical navigation devices face issues with power consumption stability and interference from ambient light, as well as increased loading on digital signal processors due to varying image capture frame rates and exposure times.
Innovation Solution
A displacement detection device comprising a touch interface, a light source, an image sensor, and a processing unit that adjusts lighting parameters based on detected displacement and contact status, entering a standby state when no object is detected to conserve power and eliminate ambient light interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the image capture frame rate is decreased to reduce power consumption, then power consumption is reduced, but the sensing region must be increased to maintain maximum detectable acceleration, causing digital signal processor loading to not linearly decrease
Solution Approach 1:
The patent applies dynamics by making the sensing region adaptive rather than fixed. The sensing region dynamically adjusts its size based on the detected moving speed of the optical navigation device. When moving speed is high, the sensing region is smaller; when moving speed is low, the sensing region is larger. This dynamic adjustment allows the system to reduce power consumption through lower frame rates while maintaining the capability to detect maximum acceleration by expanding the sensing region when needed.
2Use of energy by moving object
If the exposure time of the image sensor is changed according to moving speed, then power consumption is reduced, but the brightness of captured images appears large fluctuation, reducing stability
Solution Approach 1:
The patent applies parameter changes by adjusting multiple parameters in a coordinated manner rather than changing exposure time alone. The system changes the image capture frame rate, adjusts the sensing region size, and modifies light source illumination parameters together. This multi-parameter adjustment approach allows power consumption to be reduced while maintaining image brightness stability, as the combined effects of these parameter changes compensate for each other's variations.
3Use of energy by moving object
If the image capture frame rate is adjusted according to moving speed, then power consumption is reduced, but interference from ambient light affects detection accuracy
Solution Approach 1:
The patent applies periodic action by using pulsed or intermittent light source illumination rather than continuous lighting. The light source is activated in periodic pulses synchronized with the image capture process. This periodic illumination reduces power consumption compared to continuous lighting while improving displacement detection accuracy by creating strong temporal contrast between the illuminated periods and dark periods, making it easier to distinguish reflected light from ambient light interference.
4Reliability
If the sensing region is increased to maintain maximum detectable acceleration at low speeds, then acceleration detection capability is maintained, but digital signal processor loading does not linearly decrease
Solution Approach 1:
The patent applies local quality by making the sensing region size variable rather than uniformly large. Instead of maintaining a large sensing region at all times, the system adjusts the sensing region size locally according to the detected moving speed. When moving speed is high, a smaller sensing region suffices; when moving speed is low, the sensing region is expanded to maintain acceleration detection capability. This localized adaptation reduces unnecessary digital signal processor loading while maintaining reliability.
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 effectively reduces system power consumption and improves stability by controlling lighting and eliminating ambient light interference, maintaining consistent maximum detectable acceleration across varying speeds.
Implementation Method 1
The image sensor is configured to receive reflected light from the touch interface at a sampling frequency
Implementation Method 2
The light source is configured to provide light to the touch interface with a light source parameter
Data Source
AI summary
There is provided a displacement detection device including a light source, an image sensor and a processing unit. The light source provides light to a finger with a light source parameter. The image sensor receives reflected light from the finger, outputs valid images when the light source is being turned on and outputs dark images when the light source is being turned off. The processing unit determines a contact status according to one of the dark images and one of the valid images, and calculates a displacement according to two of the valid images to accordingly adjust the light source parameter.