LCD Lamp Driving Circuit Brightness Control via Waveform Modulation
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Solution Overview
Problem
Liquid crystal display devices face limitations in achieving an improved range of lamp brightness, with continuous mode driving methods consuming high power and burst mode methods providing a limited brightness range, while also failing to realize brightness within certain desired levels.
Innovation Solution
A lamp driving apparatus and method that includes a control signal generator producing a switching control signal, a waveform modulator adjusting the amplitude of this signal, and an AC waveform generator producing a waveform with varying peak-to-peak amplitudes within a time period to control the lamp's brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If continuous mode driving method is used, then lamp brightness is maintained at high level, but power consumption increases significantly
Solution Approach 1:
The patent applies periodic action by switching the lamp between on and off states in a pulsed manner rather than continuous operation. The control signal generator produces periodic switching signals that turn the lamp on during display refresh periods and off during other periods, reducing overall power consumption while maintaining sufficient brightness during active display periods.
Solution Approach 2:
The patent implements dynamics by making the lamp brightness and power consumption adjustable through different driving modes (continuous mode, burst mode, and hybrid mode). The system can dynamically switch between these modes based on display requirements, allowing optimization between brightness and power consumption for different operating conditions.
2Use of energy by moving object
If burst mode driving method is used, then power consumption is reduced, but brightness range becomes limited
Solution Approach 1:
The patent overcomes the limited brightness range of burst mode by introducing dynamic adjustability through multiple driving modes. The hybrid mode combines continuous and burst mode characteristics, allowing the lamp to operate at different brightness levels by adjusting the duty cycle and switching frequency, thus expanding the achievable brightness range while maintaining lower power consumption compared to full continuous mode.
Solution Approach 2:
The patent applies parameter changes by modifying the switching frequency and duty cycle of the lamp driving signal. By adjusting these parameters, the system can achieve different brightness levels and power consumption levels, effectively expanding the brightness range available in burst mode operation.
3Ease of operation
If conventional driving modes are used, then simple control is maintained, but desired brightness levels cannot be achieved
Solution Approach 1:
The patent achieves multi-functionality by designing a single lamp driving circuit that can operate in multiple modes (continuous mode, burst mode, and hybrid mode). This universal circuit design allows the system to achieve various brightness levels and power consumption levels without requiring separate control circuits for each mode, thus expanding brightness control range while maintaining control simplicity.
Solution Approach 2:
The patent expands brightness control range by adjusting key parameters such as switching frequency and duty cycle within the existing circuit architecture. By changing these parameters, the system can achieve fine-grained control over brightness levels without adding complex control mechanisms, thereby maintaining ease of operation.
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 approach enables improved brightness control by ensuring the AC waveform does not remain zero during the off-time period, allowing continuous oscillation at lower amplitudes, thus enhancing the brightness range and achieving levels previously unattainable.
Implementation Method 1
an AC waveform generator for converting a supply voltage based on the modulated switching control signal to generate an AC waveform for driving the lamp
Implementation Method 2
a lamp for generating light in accordance with the AC waveform
Implementation Method 3
a lamp for generating light in accordance with the AC waveform
Data Source
AI summary
An apparatus for driving a lamp of a liquid crystal display device includes a control signal generator generating a switching control signal, a waveform modulator modulating at least an amplitude of the switching control signal to generate a modulated switching control signal, and an AC waveform generator converting a supply voltage based on the modulated switching control signal to generate an AC waveform for driving the lamp, the AC waveform including at least two different peak-to-peak amplitudes within a time period.