Light Emitting Element Plasmon Excitation Layer Directionality
Solution Overview
Problem
Current light emitting elements for LED projectors face challenges in achieving both high luminance and directionality, with existing solutions either limiting the radiation angle or failing to provide sufficient luminance.
Innovation Solution
A light emitting element is designed with a light source layer and an optical element layer, featuring a plasmon excitation layer sandwiched between dielectric layers, which converts light into a predetermined exit angle, enhancing both luminance and directionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a light emitting element uses a fixed radiation angle (e.g., ±15°) to achieve high luminance, then luminance is improved, but directionality deteriorates because the radiation angle cannot be reduced further
Solution Approach 1:
The patent changes the optical parameters of the light emitting element by introducing a plasmon excitation layer with specific plasma frequency characteristics. This layer converts the radiation angle parameter from a fixed wide angle (±15°) to a controllable narrow angle, thereby improving directionality while maintaining luminance through optimized plasmon resonance conditions
Solution Approach 2:
The plasmon excitation layer acts as an intermediary between the light source layer and the exit layer. It mediates the conversion of light from the light source into directed output by exciting surface plasmons that propagate along the interface, enabling precise control of the exit angle while preserving luminance
2Adaptability or versatility
If the radiation angle of output light is reduced to improve directionality, then directionality is improved, but luminance deteriorates because light output at fixed angles is lost
Solution Approach 1:
The patent optimizes the plasma frequency parameter of the plasmon excitation layer to match the frequency of light from the light source. This parameter matching enables efficient energy transfer and maintains high luminance while achieving narrow radiation angles for improved directionality
Solution Approach 2:
The patent replaces conventional optical directing mechanisms with a plasmon-based electromagnetic field control mechanism. Surface plasmons provide a more efficient means of controlling light direction compared to traditional mechanical or geometric optical elements, enabling simultaneous achievement of high luminance and directionality
3Device complexity
If light is output at a fixed angle to simplify the structure, then device complexity is reduced, but light loss increases because light cannot enter the illumination optical system effectively
Solution Approach 1:
The plasmon excitation layer serves as an intermediary that converts isotropic light emission into directed output without requiring complex external optical elements. This intermediary mechanism enables efficient coupling with the illumination optical system while maintaining structural simplicity
Solution Approach 2:
The plasmon excitation layer performs multiple functions: it controls the radiation angle, maintains luminance, and enables efficient coupling with the illumination optical system. This multi-functionality reduces the need for additional optical components, thereby reducing overall device complexity while minimizing light loss
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 simultaneously increases luminance and directionality of the output light, reducing light loss and achieving the necessary etendue for effective LED projector performance.
Implementation Method 1
a light emitting element that uses plasmon coupling to output light
Implementation Method 2
due to the effect of surface plasmons propagated through an interface between micro periodic relief structure grating 116a of cathode layer 116 and the outside
Data Source
AI summary
Light source layer (4) includes substrate (10) and a pair of layers, namely, hole-transport layer (11) and electron-transport layer (13), formed on substrate (10). Directional control layer (5) includes plasmon excitation layer (15) stacked on a side of light source layer (4), which is opposite to the side of substrate (10) of light source layer (4), and which has a plasma frequency higher than a frequency of light output from light source layer (4), and wave vector conversion layer (17) stacked on plasmon excitation layer (15), which converts light incident from plasmon excitation layer (15) into light having a predetermined exit angle to output the light. Plasmon excitation layer (15) is sandwiched between low dielectric constant layer (14) and high dielectric constant layer (16).