Backlight Unit Light Shielding Layer for Uniform Illumination
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Solution Overview
Problem
Conventional backlight units for LCDs, particularly those using CCFLs, face issues with high power consumption, limited color reproduction, environmental concerns due to mercury, and high costs associated with LED-based units due to different driving mechanisms and components.
Innovation Solution
A backlight unit design incorporating a light shielding layer with varying light transmittance and a structure comprising multiple layers to reduce luminance non-uniformity, utilizing LEDs as light sources and a reflection layer to achieve uniform light distribution, and a light shielding layer with specific patterns and materials to enhance light uniformity and reduce power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If CCFLs are used as light sources in a backlight unit, then the structure is simple and easy to manufacture, but power consumption is high and color reproduction range is limited to about 70% of CRT
Solution Approach 1:
The patent changes the light source type from CCFL to LED, which fundamentally alters the operating parameters including power consumption, lifespan, and light emission characteristics. LEDs consume significantly less power while providing longer operational life and better color reproduction capabilities.
Solution Approach 2:
The patent replaces the gas discharge mechanism of CCFLs with the electroluminescence mechanism of LEDs. This substitution eliminates the need for ballasts and high voltage power supplies associated with CCFLs, simplifying the overall system while reducing power consumption.
2Reliability
If CCFLs are used as light sources, then the manufacturing process is established and reliable, but environmental pollution occurs due to mercury content
Solution Approach 1:
The patent substitutes LED technology for CCFL technology, replacing the mercury-based gas discharge system with a semiconductor-based electroluminescence system. This eliminates mercury usage entirely while maintaining manufacturing reliability through established semiconductor fabrication processes.
Solution Approach 2:
The patent adopts LEDs which, while having higher initial cost, provide significantly extended operational life (typically 50,000+ hours versus 10,000 hours for CCFLs), reducing the frequency of replacement and associated environmental impact from disposal and manufacturing cycles.
3Use of energy by moving object
If LEDs are used as light sources, then power consumption is reduced and color reproduction range is improved to 100% or more of NTSC, but driver and PCB costs increase making the system expensive
Solution Approach 1:
The patent divides the backlight unit into multiple independently controllable LED string segments, each with its own simplified driver circuit. This segmentation allows for localized control and reduces the complexity of a single centralized driver, while also enabling progressive implementation and testing.
Solution Approach 2:
The patent designs the driver circuitry to handle multiple functions including power conversion, LED string control, and fault detection within an integrated architecture. The PCB is designed to accommodate different LED configurations and future upgrades, reducing overall system complexity through standardized interfaces.
4Loss of energy
If multiple light sources are disposed under the panel in a direct type backlight unit, then light efficiency is superior, but light uniformity near the light sources becomes non-uniform
Solution Approach 1:
The patent applies different transmittance characteristics to different regions of the light shielding layer. Areas closer to light sources have higher transmittance to reduce hot spots, while areas farther away have lower transmittance to maintain overall uniformity. This local variation in optical properties compensates for the non-uniform light distribution from multiple sources.
Solution Approach 2:
The patent introduces a light shielding layer with spatially varying transmittance as an intermediary between the light sources and the display panel. This intermediate layer modulates the light intensity distribution, transforming the non-uniform output from multiple high-efficiency LED sources into a uniform illumination pattern across the display surface.
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 enables a more energy-efficient, environmentally friendly, and cost-effective backlight unit with improved light uniformity and color reproduction, suitable for a wider range of LCD applications.
Implementation Method 1
a light shielding layer with varying light transmittance... to reduce luminance non-uniformity
Implementation Method 2
utilizing LEDs as light sources and a reflection layer to achieve uniform light distribution
Data Source
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AI summary
A light generating device which may be used as a backlight unit and a display device including the light generating device are discussed. According to an embodiment, the light generating device can include a first layer; a plurality of light source devices disposed on the first layer and configured to emit light, each at least one of the light source devices including a light emitting unit diode for generating the light, a second layer covering the light source devices, and first and second light shielding layers disposed on the second layer and configure to selectively control transmit a propagation of the light emitted from the light source devices, the first and second light shielding layers being composed of a same material or different materials, the first and second light shielding layers being disposed to correspond with the light source devices.