CCFL Backlight Module Preheating via Carbon Fiber Heater
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Solution Overview
Problem
Existing liquid-crystal display (LCD) backlight modules using Cold Cathode Fluorescent Lamps (CCFLs) face challenges in initiating properly at low temperatures due to insufficient mercury vapor pressure, leading to issues with light emission and lamp life, with current solutions being either complex or detrimental to the lamp's longevity.
Innovation Solution
A backlight module incorporating a transparent film electrical heater with a carbon fiber heating structure, positioned between the reflection plate and the CCFL, which generates heat to raise the CCFL to a normal initiation temperature, avoiding the need for over-power voltages and ensuring the lamp's longevity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If preheating via external heating source (ITO film heater) is used, then low temperature initiation is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The invention extracts the heating function from the complex ITO film heater system and implements it directly through the CCFL's own over-power voltage capability. The CCFL serves dual purposes: as the light source and as the heating element during preheating, eliminating the need for separate heating components and their associated complexity.
Solution Approach 2:
The CCFL is designed to perform multiple functions: it serves as both the primary light source and the heating element for preheating. By applying over-power voltage, the CCFL generates heat to warm the mercury and facilitate vaporization, thereby initiating the discharge process without requiring external heating devices.
2Reliability
If preheating via external heating source (ITO film heater) is used, then low temperature initiation is improved, but assembly difficulty and yield rate decrease
Solution Approach 1:
The invention removes the separate heating device (ITO film heater) from the system and integrates the heating function into the CCFL itself. This eliminates the need for additional assembly steps involving heating components, thereby improving ease of manufacture and assembly.
Solution Approach 2:
The CCFL performs self-heating by utilizing over-power voltage to generate the necessary heat for mercury vaporization. This self-service capability eliminates the need for external heating systems and their associated assembly complexities, improving manufacturing efficiency and yield rate.
3Speed
If over-power voltage is applied during low temperature initiation, then mercury vaporization speed is improved, but lamp tube life is reduced
Solution Approach 1:
The invention applies over-power voltage only during the preliminary initiation phase to accelerate mercury vaporization and establish discharge. Once the CCFL is successfully initiated and operating normally, the voltage is reduced to standard operating levels, thereby minimizing the duration of high-stress conditions and preserving lamp tube life.
Solution Approach 2:
The voltage application is divided into periodic phases: an initial high-voltage phase for rapid mercury vaporization and initiation, followed by a normal operating phase with standard voltage. This periodic action ensures fast initiation while limiting exposure to damaging high-power conditions, thus extending lamp tube life.
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
Effectively initiates the CCFL at temperatures below zero degrees Celsius without reducing its lifespan, ensuring reliable operation and extending the lamp's life by controlled heating, thus providing a more efficient and durable solution compared to existing methods.
Implementation Method 1
a middle layer of the three layers is a carbon fiber heating structure
Implementation Method 2
raise temperature of the lamp tube of the CCFL rapidly and facilitate mercury being volatilized to mercury vapor fast
Data Source
AI summary
The present invention discloses a backlight module, comprising a back plate, a reflection plate, a cold cathode fluorescent lamp (CCFL), an optical film, a panel and a front frame, wherein the backlight module further comprises a heating device, and the heating device is disposed between the reflection plate and the CCFL. When the backlight module of the present invention is used in a cold area, the heating device is electrically powered in advance to generate heat and to heat the CCFL, and temperature of the CCFL can be raised to a normal initiation temperature which is above ten degrees below zero. Accordingly, the CCFL can avoid usage of over-power voltages in low temperature initiation thereof, and the life of the CCFL is less affected.