Illuminance Sensor Correction Using IR Floor Reflectance
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Solution Overview
Problem
Display devices face inaccuracies in sensing ambient illuminance due to the placement of sensors, which are often at the lower end and affected by direct and reflected light, leading to varying readings based on floor colors and materials, even under the same lighting conditions.
Innovation Solution
Incorporating an IR sensor at the lower side of the display device to calculate floor reflectance, using correction data to adjust illuminance values sensed by an illuminance sensor, and controlling display operations based on these corrected values, including brightness and audio output attributes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the illuminance sensor is disposed at the lower end of the display device, then the sensor can be positioned in devices without bezel parts or with thin configurations, but the sensing accuracy deteriorates due to direct light and reflected light from the floor
Solution Approach 1:
An IR sensor is introduced as an intermediary device to detect floor reflectance characteristics. The IR sensor measures the reflected infrared light from the floor, and this information is used to calculate a correction factor that compensates for the illuminance sensor's inaccurate readings caused by floor reflections.
Solution Approach 2:
The system implements a feedback mechanism where the illuminance sensor continuously monitors ambient light, the IR sensor detects floor reflectance, and the processor uses this combined information to dynamically correct the illuminance values. The corrected illuminance values are then used to control display brightness, creating a closed-loop system that adapts to different floor conditions.
2Device complexity
If the sensor measures ambient light at the lower end position, then the device structure is simplified, but the sensing values vary significantly with different floor colors and materials
Solution Approach 1:
The IR sensor serves as an intermediary that specifically detects floor reflectance properties without being affected by the display's own light emissions. By measuring infrared radiation reflected from the floor, it provides independent information about floor characteristics that can be used to correct the illuminance sensor's readings.
Solution Approach 2:
The system changes the measurement parameter by using the IR sensor to detect infrared reflectance, which correlates with visible light reflectance of the floor. This allows the system to infer floor reflectance characteristics in the visible spectrum by measuring in the infrared spectrum, thereby correcting illuminance readings without requiring multiple visible light sensors.
3Measurement precision
If correction based on floor material is implemented, then sensing accuracy is improved, but additional sensors and processing requirements increase device complexity
Solution Approach 1:
The IR sensor, while primarily designed for infrared detection, is utilized multi-functionally to detect floor reflectance characteristics. This allows the same sensor to serve both its original purpose and the additional function of floor characterization, reducing the need for separate dedicated sensors for each measurement task.
Solution Approach 2:
The display device uses its own infrared emissions (from the display panel and other components) as the light source for the IR sensor to detect floor reflectance. This self-service approach eliminates the need for separate infrared illumination sources, as the display's own infrared radiation is sufficient for measuring floor reflectance properties.
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
Accurately correcting sensor readings for reflected light effects, enabling precise control of display brightness and audio output based on the installation environment, improving user experience by adapting to different lighting conditions and floor types.
Implementation Method 1
an IR sensor disposed at a lower side of the display device... calculate a reflectance of a floor surface... based on a sensing value of the IR sensor
Implementation Method 2
there is the problem of not only the effect of direct light but also the effect of reflected light increasing... Because reflected light reflects an amount of light differently according to a floor color or material
Data Source
AI summary
A display device includes a display, an illuminance sensor, an IR sensor disposed at a lower side of the display device, a memory to store correction data set by respective reflectance, and a processor. The processor is configured to calculate a reflectance of a floor surface, in an environment in which the display device is arranged, based on a sensing value of the IR sensor, obtain correction data corresponding to the calculated reflectance from stored correction data of the memory, correct an illuminance value sensed by using the illuminance sensor according to the obtained correction data, and control an operation of the display based on the corrected illuminance value.