LCD Backlight PWM and Current Control for Power Efficiency
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Solution Overview
Problem
Conventional LED backlight systems in liquid crystal display devices can only perform luminance control using either Pulse Width Modulation (PWM) or current value control systems, lacking a mechanism to effectively combine both for optimal power consumption reduction and picture quality, especially when displaying images.
Innovation Solution
A liquid crystal display device that combines PWM and current value control systems to adjust light emission luminance, using specific picture quality modes to optimize duty cycles and current values, allowing concurrent and gradual changes to achieve efficient power usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If PWM system is used for luminance control, then control accuracy is improved, but power efficiency deteriorates
Solution Approach 1:
The patent combines PWM control and current value control into a unified control system. The control unit selectively applies PWM control for high precision requirements and current value control for power efficiency, merging the advantages of both systems to resolve the contradiction between control accuracy and power efficiency.
2Use of energy by moving object
If current value control system is used for luminance control, then power efficiency is improved, but control precision deteriorates
Solution Approach 1:
The control system dynamically switches between current value control and PWM control based on operational conditions. The control unit determines when to apply each control method, making the system adaptive and dynamic to optimize both power efficiency and control precision根据不同 situations.
3Use of energy by moving object
If both PWM and current value control systems are combined, then power consumption can be reduced, but system complexity increases
Solution Approach 1:
The control unit is designed to perform multiple functions: it can execute PWM control, current value control, and selectively switch between them. This multi-functional design allows the system to reduce power consumption while managing complexity through a unified control interface that handles both control methods.
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 combination reduces power consumption by efficiently controlling LED lighting according to picture quality modes, enhancing power efficiency without compromising image quality or user experience.
Implementation Method 1
a light source of a light-emitting diode for irradiating the liquid crystal panel
Data Source
AI summary
In an LCD device, picture quality luminance is controlled through the combination of pulse-width modulation (PWM) system and current value control system, reducing the electrical power consumption associated with turning on an LED. In the LED backlight, the light emitting luminance of the LED is controlled by both PWM and also by current value control, which selects the value of the current supplied to the LED from a plurality of set values. At least one of the plurality of set values is a predetermined current value at which duty reaches a maximum value at the maximum luminance value used in a specified picture quality mode of the picture quality modes established in the liquid crystal display device. In the aforementioned specified picture quality mode, the greatest luminance value to be used is smaller than at least the greatest luminance value used in other specified picture quality modes.