Crystalline Color-Conversion Device for Efficient White Light
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Solution Overview
Problem
Current light-emitting technologies face inefficiencies and uniformity issues in producing colored light, particularly in solid-state lighting and displays, due to variability in LED materials and manufacturing processes, leading to performance inefficiencies and non-uniformity, as well as inefficiencies in color conversion processes.
Innovation Solution
A crystalline color-conversion device is developed, featuring an electrically driven first light emitter, such as a blue or ultraviolet LED, in close proximity to an inorganic solid single-crystal direct-bandgap second light emitter, where the first light is absorbed and re-emitted at a lower energy, enabling efficient production of colored light with improved optical and electrical efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If multiple different colored solid-state light emitters are used to provide white light, then color rendering index is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent combines multiple colored light emitters (blue LED and yellow phosphor) into a single integrated device structure, where the blue LED excites the yellow phosphor to produce white light. This merging approach achieves high color rendering index while reducing device complexity compared to using separate emitters.
Solution Approach 2:
The patent utilizes phosphor materials that convert blue light to yellow light through photoluminescence, creating a color transformation that when combined with the remaining blue light produces white light with excellent color rendering properties.
2Illumination intensity
If phosphors are used as color-conversion materials, then colored light production is achieved, but conversion efficiency decreases and materials fade over time
Solution Approach 1:
The patent optimizes phosphor parameters including particle size, composition, and excitation wavelength matching to maximize conversion efficiency. By carefully selecting phosphor materials with bandgaps that closely match the blue LED emission, the system achieves high efficiency light conversion while maintaining material stability.
3Illumination intensity
If crystalline-based inorganic LEDs are used, then brightness and color saturation are improved, but manufacturing cost and difficulty increase
Solution Approach 1:
The patent employs composite material structures combining crystalline semiconductor layers with phosphor materials. This composite approach leverages the high brightness and color saturation of crystalline LEDs while using phosphors to achieve desired colors, simplifying manufacturing compared to growing different colored crystalline layers.
4Illumination intensity
If color filters are used with white-light emitters, then colored light is produced, but much of the white light is wasted
Solution Approach 1:
The patent replaces the mechanical filtering approach (color filters that block unwanted wavelengths) with a photoluminescence-based approach where phosphors convert specific wavelengths to desired colors. This substitution eliminates waste by converting rather than blocking light, achieving high efficiency colored light production.
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 enhances optical efficiency, achieves highly saturated colored light, and improves electrical efficiency while allowing for robust and cost-effective manufacturing, addressing the inefficiencies and uniformity issues in existing technologies.
Implementation Method 1
an electrically driven first light emitter for emitting light having a first energy in response to an electrical signal
Implementation Method 2
the second light emitter is located in optical association with the first light emitter so that in response to the electrical signal the first light emitter emits light that is absorbed by the second light emitter and the second light emitter emits light of a lower energy than the first light emitter
Data Source
AI summary
According to an embodiment, a crystalline color-conversion device includes an electrically driven first light emitter, for example a blue or ultraviolet LED, for emitting light having a first energy in response to an electrical signal. An inorganic solid single-crystal direct-bandgap second light emitter having a bandgap of a second energy less than the first energy is provided in association with the first light emitter. The second light emitter is electrically isolated from, located in optical association with, and physically connected to the first light emitter so that in response to the electrical signal the first light emitter emits first light that is absorbed by the second light emitter and the second light emitter emits second light having a lower energy than the first energy.