Optoelectronic Component Absorber Contrast Enhancement
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Solution Overview
Problem
Existing optoelectronic components face challenges in achieving high contrast between emitters, particularly in pixelated LEDs, due to limitations in channel separation and efficiency losses associated with grating use, and require methods to adjust contrast without compromising brightness or incurring additional costs.
Innovation Solution
Incorporating an absorber with a lower absorption coefficient in regions associated with active emitters and using phase change materials or saturable absorbers, which can be thermally or optically switched to alter their absorption properties, allowing for independent control of emitter states and contrast adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a grating is used to improve channel separation between emitters, then contrast is improved, but efficiency is reduced due to light loss
Solution Approach 1:
The invention changes the optical parameters of the conversion layer by incorporating absorbers with specific absorption coefficients. The absorber concentration and distribution are adjusted to achieve the desired contrast enhancement while minimizing light loss. This allows tuning of the system to balance contrast and efficiency differently from fixed grating structures.
Solution Approach 2:
The absorbers are selectively distributed within the conversion layer, with higher concentrations in regions between emitters and lower concentrations directly over emitters. This local variation in absorber density creates spatially selective contrast enhancement that preserves more light from the emitters compared to uniform grating structures.
2Measurement precision
If contrast enhancement structures are added to improve emitter separation, then channel separation is improved, but device complexity increases
Solution Approach 1:
The absorber-containing conversion layer combines multiple functions into a single component: wavelength conversion (via phosphors), contrast enhancement (via absorbers), and light extraction optimization. This merged structure eliminates the need for separate grating structures or additional contrast-enhancing layers, reducing overall device complexity.
Solution Approach 2:
The conversion layer is formulated as a composite material containing both phosphor particles for wavelength conversion and absorber particles for contrast enhancement. This composite approach integrates multiple optical functions within a single material layer, simplifying the overall device architecture compared to using multiple separate layers or structures.
3Measurement precision
If absorber concentration is increased to enhance contrast, then contrast is improved, but brightness is reduced
Solution Approach 1:
The absorber concentration is varied spatially within the conversion layer, with higher concentrations positioned in regions between emitters where contrast enhancement is needed, and lower concentrations directly over emitters where light extraction is prioritized. This spatial differentiation allows contrast improvement without proportionally sacrificing overall brightness.
Solution Approach 2:
Rather than uniformly increasing absorber concentration throughout the entire conversion layer, the invention applies absorbers selectively in specific regions where they provide maximum contrast benefit. This partial application of absorbers achieves the desired contrast enhancement while minimizing the impact on overall light output and brightness.
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 approach enhances contrast by up to 200% between active and inactive emitters, allowing for flexible adjustment post-manufacturing, while maintaining or reducing brightness, and avoiding additional processing costs, thus improving channel separation and component efficiency.
Implementation Method 1
the absorber comprises a lower absorption coefficient in first regions associated with emitters in the first operating state than in second regions associated with emitters in the second operating state
Implementation Method 2
heating the absorber to a temperature above the glass transition temperature, cooling the absorber in the first regions to a temperature below the glass transition temperature in a time t1, and cooling the absorber in the second regions to a temperature below the glass transition temperature in a time t2, wherein t1<t2
Data Source
AI summary
An optoelectronic component includes a semiconductor chip with a plurality of emitters that emit a primary radiation in a main radiation direction in a first state and do not emit primary radiation in a second state, and an absorber arranged subsequent to the emitters in the main radiation direction, wherein the absorber includes a lower absorption coefficient in first regions associated with emitters in the first state than in second regions associated with emitters in the second state, a conversion layer arranged in the main radiation direction on at least one emitter of the semiconductor chip, and 1) the absorber is present in particle form embedded in the conversion layer, or 2) the absorber is present in an absorber layer, wherein the absorber layer is arranged in the main radiation direction on a side of the conversion layer facing away from the chip, and the absorber layer is electrically contacted.