FED Backlight Phosphor Alignment for LCD Black Levels
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional liquid crystal displays (LCDs) face challenges in achieving high-quality backlighting with programmability, motion blur elimination, and cost-effectiveness, as they often require expensive LED backlights and complex configurations.
Innovation Solution
The use of Field Emission Device (FED) backlights with programmable phosphor elements, aligned using direct electrostatic or electrophotographic screening processes, allows for intelligent backlighting with reduced costs and enhanced performance, eliminating the need for color filters and achieving superior black levels and dynamic range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If LED backlights are used to achieve superior black levels and enhanced dynamic range, then image quality is improved, but manufacturing cost increases
Solution Approach 1:
The backlight is divided into multiple independently controllable segments or zones, allowing selective illumination of different regions. This segmentation enables the system to achieve superior black levels by turning off specific segments when not needed, while using cost-effective LED technology rather than expensive full-array LEDs throughout the entire display.
Solution Approach 2:
Different regions of the backlight are provided with different characteristics - some areas have enhanced illumination capabilities while others have reduced or eliminated backlighting. This local quality approach allows the display to achieve superior black levels in specific regions without requiring expensive LED backlights across the entire panel, thereby reducing manufacturing costs.
2Illumination intensity
If multiple cold cathode fluorescent lamps are arranged and activated in sequence to achieve scrolling and eliminate motion blur, then motion clarity is improved, but device complexity increases
Solution Approach 1:
The backlight system transitions from a static configuration to a dynamic one where illumination is actively controlled and adjusted in real-time. By sequentially activating different backlight segments in synchronization with the display refresh rate, the system eliminates motion blur without requiring a complex array of permanently illuminated lamps, thereby reducing device complexity.
Solution Approach 2:
The backlight operates in periodic cycles, activating different segments in sequence synchronized with the display's refresh rate. This periodic action creates the scrolling effect and eliminates motion blur by ensuring that each segment is illuminated only when its corresponding region is being displayed, simplifying the overall device configuration compared to having all lamps continuously active.
3Adaptability or versatility
If LEDs are uniformly distributed behind the liquid crystal material to achieve programmability and performance gains, then adaptability is improved, but device complexity increases
Solution Approach 1:
The uniformly distributed LED array is divided into multiple independently controllable segments or zones. This segmentation provides programmability by allowing selective activation of different regions, enabling features like local dimming, motion blur elimination, and color field sequential operation, while reducing the number of individually controlled LEDs compared to a fully uniform distribution.
Solution Approach 2:
The segmented backlight system is designed to perform multiple functions - it can operate in full-array mode for uniform illumination, in localized mode for black level enhancement, in scrolling mode for motion blur elimination, and in color field sequential mode for additional programmability. This multi-functionality achieves high adaptability without requiring separate systems for each feature, thereby reducing overall device complexity.
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
FED backlights provide programmable, cost-effective intelligent backlighting with improved color gamut, motion clarity, and reduced costs, comparable to LED performance without the need for active switches or complex configurations.
Implementation Method 1
a field emission device (FED) having a cold cathode and an anode opposite the cold cathode and spaced apart a predetermined distance
Implementation Method 2
individual phosphor materials or individual patches of phosphor materials applied to the anode
Implementation Method 3
aligning using direct electrostatic or electrophotographic screening processes
Implementation Method 4
setting electric field lines between the mask and the anode plate by applying one voltage to the conductor and applying another voltage on the mask; and forming phosphor elements on the selected regions by injecting a flux of charged phosphor particles toward the mask
Data Source
AI summary
An LCD display has a programmable backlight device that produces multiple different color fields from multiple different phosphor elements. The backlight device can be a low resolution FED device. The phosphor is applied by an electrophotographic screening process or direct electrostatic screening process. The FED device can further incorporate a wide gamut phosphor.