Ambient-Light Current Switching for Outdoor Display Luminance
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Solution Overview
Problem
Outdoor digital signage faces challenges in controlling luminance due to uncontrollable external environments, such as varying illuminance caused by daylight and weather conditions, leading to issues with gamma and grayscale expression.
Innovation Solution
A display device with multiple current output units and a processor that adjusts the connection of drivers based on light measurements, using resistors or voltages with different values to maintain optimal luminance without loss in gamma and grayscale expression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If outdoor digital signage is installed to provide advertisements and information outdoors, then it can be accessed by users in outdoor environments, but it cannot control luminance due to uncontrollable external environment conditions
Solution Approach 1:
The patent implements dynamic luminance control by switching between different current output units (first and second current output units) based on ambient light conditions detected by a sensor. The system dynamically adjusts the driving current to the display during daytime and nighttime, enabling adaptation to outdoor environmental changes while maintaining image quality
Solution Approach 2:
The patent employs a feedback mechanism where a sensor detects ambient light conditions and provides information to a controller, which then adjusts the luminance by selecting appropriate current output units. This closed-loop feedback system enables the display to automatically adapt to changing outdoor lighting conditions
2Illumination intensity
If different current output units are used for daytime and nighttime, then luminance control is achieved, but device complexity increases
Solution Approach 1:
The patent achieves multi-functionality by designing a driver that can operate with different current output units (first and second current output units) depending on ambient light conditions. The same driver structure serves both daytime and nighttime operations, reducing overall system complexity while maintaining luminance control capability
Solution Approach 2:
The patent controls luminance by changing electrical parameters (current output levels) rather than using entirely different hardware configurations. By adjusting the current parameters through different output units and resistor combinations, the system achieves luminance control with minimal structural complexity
3Illumination intensity
If high current is used during daytime for high luminance, then visibility is improved, but power consumption increases
Solution Approach 1:
The patent implements dynamic power management by switching between different current output units based on ambient light conditions. During daytime, higher current is supplied for bright visibility, while during nighttime, lower current is used to reduce power consumption, optimizing the balance between visibility and energy usage
Solution Approach 2:
The sensor-based feedback system detects ambient light levels and automatically adjusts the current output to the display, ensuring that power consumption is optimized according to actual viewing conditions while maintaining adequate visibility
4Device complexity
If luminance is not controlled in outdoor environments, then the display can operate without complex control mechanisms, but gamma and grayscale expression are lost
Solution Approach 1:
The patent maintains image quality by precisely controlling current parameters through different output units and resistor combinations. This parameter-based control approach preserves gamma and grayscale expression while avoiding the need for complex hardware modifications
Solution Approach 2:
The driver is designed to universally handle both high-current daytime operation and low-current nighttime operation while maintaining consistent image quality characteristics. The same driver circuitry preserves gamma and grayscale accuracy across different operating conditions without requiring separate specialized circuits
Data Source
AI summary
A display device according to embodiments comprises: a display which includes a plurality of display modules; a sensor which measures light intensity to which the display is exposed; one or more driving units which drive the display; two or more current output units which are connected to each of the one or more driving units and output different currents; and a processor which controls the driving units to be connected to at least one of the two or more current output units, on the basis of the light intensity measured by the sensor.