RGB Backlight Color Calibration Circuit for White Point Stability
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Solution Overview
Problem
The color variation of white light emitted by RGB backlight sources in liquid crystal display modules due to differential light attenuation of red, green, and blue light-emitting diodes over time, leading to undesirable color shifts in the displayed images.
Innovation Solution
A color calibration circuit and method that includes a backlight source with red, green, and blue light-emitting diodes, a light sensor, and a controller to adjust driving currents based on light intensity signals to maintain a specified light intensity ratio, ensuring consistent white light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If RGB light-emitting diodes are used as backlight source, then color display capability is improved, but color stability deteriorates due to differential light attenuation over time
Solution Approach 1:
The patent implements a feedback mechanism where a light sensor continuously monitors the light intensity of each RGB light-emitting diode, and a controller adjusts the driving current to each diode based on the detected intensity to maintain uniform color output. This closed-loop feedback system compensates for differential attenuation and maintains color stability over time.
Solution Approach 2:
The patent dynamically changes the operating parameters (driving current) of each light-emitting diode based on its individual light intensity characteristics. By adjusting the current parameters in real-time, the system compensates for attenuation differences and maintains consistent color performance.
2Illumination intensity
If driving current is increased to compensate for light attenuation, then light intensity is improved, but energy consumption increases
Solution Approach 1:
The patent applies local quality adjustment by individually tailoring the driving current to each light-emitting diode based on its specific light intensity characteristics. Instead of uniformly increasing current to all diodes, the system selectively adjusts current only where needed to maintain light intensity, thereby minimizing energy consumption.
Solution Approach 2:
The system dynamically optimizes energy consumption by changing the driving current parameters based on actual light intensity requirements. The controller adjusts current levels to maintain desired illumination while minimizing excess energy usage, adapting parameters in real-time to operational conditions.
3Measurement precision
If calibration is performed during start-up procedure, then color accuracy is improved, but calibration time is reduced
Solution Approach 1:
The patent performs color calibration during the start-up procedure before normal operation begins. This preliminary calibration establishes the baseline light intensity characteristics of each diode, enabling accurate color display from the outset without requiring separate calibration time during operation.
Solution Approach 2:
The calibration process is seamlessly integrated into the start-up procedure, ensuring continuous useful action. The system completes calibration as part of the initialization process, maintaining color accuracy throughout operation without interrupting or extending the overall system activation time.
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
Maintains the desired light intensity ratio of red, green, and blue light beams, preventing color variation in the white light output and ensuring stable image quality over time.
Implementation Method 1
a light sensor to detect a light intensity of each of the red light beam, the green light beam, and the blue light beam
Implementation Method 2
The backlight source includes plural red light-emitting diodes, plural green light-emitting diodes, and plural blue light-emitting diodes
Implementation Method 3
the white light beam from the backlight source is emitted by plural white light-emitting diodes
Data Source
AI summary
A color calibration circuit and a calibration method for a backlight source of a liquid crystal display module are provided. The backlight source is an RGB backlight source. When the calibration method is performed, the controller receives three color light intensity signals from a light sensor, and three updated driving currents are calculated. Then, the controller provides the driving currents to the backlight source. Consequently, the red light beam, the green light beam, and the blue light beam emitted by the backlight source are mixed as a white light beam, and the white light beam is not subjected to color variation.