Ambient-Adaptive Backlight Color Control for Displays
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Solution Overview
Problem
Conventional electronic device displays face issues with displaying shades of white due to excessive pixel value truncation and motion blur, especially when transitioning between different ambient lighting conditions, as they often rely on backlights with single-color light sources that fail to adapt to ambient light colors.
Innovation Solution
Incorporating a backlight with multiple light-emitting diodes of different colors, such as warm and cool white LEDs, and a color ambient light sensor to adjust the intensity of these LEDs based on ambient light conditions, allowing the display to dynamically match the ambient light color and reduce pixel value truncation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-color backlight is used, then the device complexity is reduced, but the display accuracy and color representation deteriorate when displaying different shades of white
Solution Approach 1:
The backlight is segmented into multiple independent light sources with different color characteristics (warm white and cool white LEDs). Each light source can be independently controlled to produce different color temperatures, allowing the system to achieve accurate color representation without excessive complexity.
Solution Approach 2:
The backlight system dynamically adjusts the intensity ratio between warm white and cool white LED sources based on ambient lighting conditions detected by the sensor. This dynamic adaptation enables the display to maintain color accuracy across varying environmental conditions.
2Temperature
If pixel values are significantly reduced to display warmer white, then the color temperature matches ambient light, but brightness loss and motion blur artifacts increase
Solution Approach 1:
Instead of changing pixel values to adjust color temperature, the system changes the physical parameter of the backlight itself by varying the intensity ratio between warm and cool white LED sources. This approach adjusts color temperature without the harmful side effects of pixel value truncation.
3Device complexity
If the backlight color is fixed, then the device complexity is reduced, but the adaptability to different ambient lighting conditions deteriorates
Solution Approach 1:
The system incorporates an ambient light sensor that provides feedback about the surrounding lighting conditions. This feedback is used by the control circuitry to automatically adjust the backlight color temperature by changing the intensity ratio between warm and cool white LED sources, enabling seamless adaptation to different environments.
4Adaptability or versatility
If multiple light-emitting diodes of different colors are used, then the adaptability to ambient light improves, but the device complexity increases
Solution Approach 1:
The patent combines multiple LED light sources (warm white and cool white) into a single integrated backlight module that is controlled by a unified control circuit. This merging approach achieves ambient light adaptability while managing system complexity through integrated design.
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 solution enhances display performance by minimizing brightness loss and motion blur artifacts, enabling more accurate color representation and improved user experience across varying lighting environments without the need for excessive pixel value adjustments.
Implementation Method 1
The backlight may include at least first and second light-emitting diodes that emit light having different color temperatures. The first light-emitting diode may, for example, produce warm white light having a color temperature less than 6,500 K and second light-emitting diode may produce cool white light having a color temperature greater than 6,500 K
Implementation Method 2
The electronic device may include a color ambient light sensor that measures the color of ambient light and control circuitry that adjusts the color of light emitted from the backlight based on the color of ambient light
Implementation Method 3
Liquid crystal displays include a backlight for producing light that is transmitted through a layer of liquid crystal material. Pixels in a liquid crystal display contain thin-film transistors and electrodes for applying electric fields to the liquid crystal material. The strength of the electric field in a pixel controls the polarization state of the liquid crystal material and thereby adjusts the amount of backlight that is transmitted through the pixel
Data Source
AI summary
An electronic device may be provided with a display having a backlight with light sources of different colors. The electronic device may include a color ambient light sensor that measures the color of ambient light and control circuitry that adjusts the color of light emitted from the backlight based on the color of ambient light. The light sources may include at least first and second light-emitting diodes that emit light having different color temperatures. The control circuitry may adjust the intensity of light emitted from the first light-emitting diode relative to the intensity of light emitted from the second light-emitting diode to produce a backlight color that more closely matches the color of ambient light. The first and second light-emitting diodes may include an ultraviolet light-emitting diode die and a blue light-emitting diode die that are mounted in a common semiconductor package.