Blue LED Array with Phosphor Overlay for Large Displays
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Solution Overview
Problem
Large format digital color displays using RGB LEDs face issues with color inconsistency due to differential thermal performance and aging, as well as an aesthetically unpleasing appearance from individually visible red, green, and blue LEDs.
Innovation Solution
Implementing an array of single color blue LEDs with a phosphor overlay that converts blue light into red and green light, providing a consistent color output and a flush surface for improved aesthetics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If RGB LEDs are used to implement large format displays, then color variety and display capability are improved, but color inconsistency and visual appearance deteriorate due to differential thermal performance and aging
Solution Approach 1:
The invention segments the color generation function by separating the light source (blue LEDs) from the color conversion function (phosphor materials). Each pixel contains multiple blue LEDs that excite different phosphor materials to produce red, green, and blue colors. This segmentation eliminates the need for multiple LED types per pixel, ensuring all LEDs operate under identical conditions and age uniformly, thus maintaining color consistency while achieving full color capability.
2Adaptability or versatility
If RGB LEDs are used to implement large format displays, then display functionality is improved, but visual appearance deteriorates due to prominently visible individual LEDs
Solution Approach 1:
The invention introduces a phosphor overlay as an intermediary layer between the blue LED array and the viewer. This overlay contains phosphor materials that convert the blue light into full-color output. The phosphor layer acts as a mediator that transforms the appearance from discrete blue LED points into a continuous, uniform color field, eliminating the visible individual LED structure while preserving full display functionality.
3Adaptability or versatility
If multiple types of LEDs (red, green, blue) are used in each pixel, then color capability is improved, but device complexity increases due to differential drive requirements
Solution Approach 1:
The invention applies universality by using a single type of blue LED for all light generation across the entire display. These blue LEDs serve multiple functions: directly producing blue light and exciting phosphor materials to produce red and green light. This multi-functionality eliminates the need for separate drive circuits for different LED types, simplifying the drive electronics while maintaining full color capability through phosphor conversion.
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 solution eliminates color drifts and inconsistencies, simplifies drive electronics, and offers a visually appealing surface, ensuring consistent and high-quality images across larger displays.
Implementation Method 1
The printed phosphor portions of the overlay includes a number of regions of blue light excitable phosphor materials that are configured to convert, by a process of photoluminescence, blue excitation light generated by the light sources into green or red and colored light.
Data Source
AI summary
An improved approach is described to implement an LED-based large area display which uses an array of single color solid state lighting elements (e.g. LEDs). In some embodiments, the panel comprises an array of blue LEDs, where each pixel of the array comprises three blue LEDs. An overlay is placed over the array of blue LEDs, where the overlay comprises a printed array of phosphor portions. Each pixel on the PCB comprised of three blue LEDs is matched to a corresponding portion of the overlay having the printed phosphor portions. The printed phosphor portions of the overlay includes a number of regions of blue light excitable phosphor materials that are configured to convert, by a process of photoluminescence, blue excitation light generated by the light sources into green or red and colored light. Regions of the overlay associated with generating blue light comprise an aperture/window that allows blue light to pass through the overlay.