Backlight Control Circuit Frequency Regulation via Temperature Feedback
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Solution Overview
Problem
Backlight control circuits for liquid crystal displays with fixed frequency settings result in reduced luminous efficiency of cold cathode fluorescent lamps due to deviations from optimal working frequencies at varying temperatures.
Innovation Solution
A backlight control circuit with a frequency setting circuit that adjusts the frequency of the pulse control signal based on the lamp's temperature using a temperature sensor, look-up table, encoder, and digitally adjustable resistor to maintain optimal working frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed frequency setting is used in the backlight control circuit, then the circuit structure is simple, but the luminous efficiency decreases when the lamp temperature changes from normal working temperature
Solution Approach 1:
The patent applies the Dynamics principle by making the frequency setting circuit adjustable based on temperature conditions. Instead of using fixed frequency components, the circuit dynamically changes the working frequency according to the lamp's temperature, allowing the system to adapt to varying operating conditions and maintain optimal luminous efficiency across different temperature ranges
Solution Approach 2:
The patent implements Parameter changes by modifying the working frequency parameter in response to temperature changes. The frequency setting circuit adjusts the frequency parameter based on detected temperature conditions, enabling the system to optimize performance by changing this critical operating parameter rather than maintaining a fixed value
2Loss of energy
If the working frequency is adjusted according to temperature, then the luminous efficiency is maintained, but the device complexity increases due to additional temperature detection and frequency adjustment components
Solution Approach 1:
The patent applies the Feedback principle by implementing a temperature detection mechanism that continuously monitors the lamp's temperature and feeds this information back to the frequency setting circuit. This closed-loop feedback system enables automatic frequency adjustment based on actual operating conditions, maintaining optimal efficiency without requiring manual intervention or complex external control systems
Solution Approach 2:
The patent implements Self-service by enabling the frequency setting circuit to automatically adjust the working frequency based on temperature detection, without requiring external control or manual intervention. The system serves itself by autonomously optimizing its operating parameters in response to changing conditions, reducing the need for additional complex control mechanisms
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
The solution ensures that the lamp operates at its optimal working frequency regardless of temperature changes, maintaining high luminous efficiency.
Implementation Method 1
a frequency setting circuit which is configured to regulate a working frequency of a lamp according to a temperature of the lamp
Data Source
AI summary
An exemplary backlight control circuit includes an inverter, a pulse width modulation (PWM) circuit, and a frequency setting circuit. The inverter is configured to provide an alternating current voltage to a lamp. The PWM circuit is configured to provide a pulse control signal to the inverter. The frequency setting circuit is configured to regulate a frequency of the pulse control signal provided by the PWM circuit according to a temperature of the lamp.