Segmented LED With Wavelength Conversion for Color Crosstalk Control
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Solution Overview
Problem
Semiconductor light-emitting devices, such as LEDs, face challenges in achieving precise color control and reducing optical crosstalk between closely spaced segments, which can alter the color point or spectrum of the composite light output, especially when using arrays of individual LEDs.
Innovation Solution
A segmented LED design with a fully converting wavelength converting layer that limits unconverted pump light to less than 10% of the total light output, allowing individual segments to be addressed for precise color control and eliminating unwanted color emission from neighboring segments by converting stray light to the desired spectrum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If arrays of individual LEDs are used to increase brightness, then illumination intensity is improved, but optical crosstalk between closely spaced segments occurs which alters color point and spectrum
Solution Approach 1:
The LED device is divided into multiple independently controllable segments on a single die, with trenches providing electrical insulation between segments. This allows individual segment control to prevent optical crosstalk while maintaining high brightness through array configuration.
Solution Approach 2:
A wavelength converting layer is introduced as an intermediary between the LED segments and the external environment. This layer converts pump light to desired wavelengths and filters out unwanted spectral components, preventing color contamination from adjacent segments.
2Volume of moving object
If segments are closely spaced to reduce device size, then volume is reduced, but optical crosstalk between segments increases
Solution Approach 1:
The device is segmented into electrically isolated regions using trenches, enabling close spacing of segments while maintaining independent control. This prevents optical crosstalk between closely spaced segments, preserving color purity despite reduced device volume.
Solution Approach 2:
The wavelength converting layer acts as an optical intermediary that converts pump light to specific wavelengths and blocks stray light from adjacent segments, maintaining color purity even when segments are closely spaced.
3Ease of manufacture
If a single wavelength converting layer covers all segments, then manufacturing complexity is reduced, but optical crosstalk between segments cannot be prevented
Solution Approach 1:
The wavelength converting layer is segmented into separate layers for each LED segment, allowing independent optimization of conversion characteristics for each segment. This prevents optical crosstalk while maintaining manufacturing feasibility through standardized processes.
Solution Approach 2:
Each wavelength converting layer is tailored to the specific requirements of its corresponding segment, with optimized thickness and material composition. This local optimization enables precise color control for each segment while preventing interference from neighboring segments.
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 enables accurate color point and spectrum selection, preventing optical crosstalk and maintaining consistent illumination across the scene, even when projecting images with segmented LEDs, thus enhancing the precision and uniformity of light output in applications like camera flashes and lighting systems.
Implementation Method 1
a fully converting wavelength converting layer that converts stray light to the desired spectrum
Data Source
Figure 1A~1B
Figure 1C~1D
Figure 1E~1F
AI summary
A segmented light or optical power emitting device and an illumination device are described. The segmented device includes a die having a light or optical power emitting semiconductor structure that includes an active layer disposed between an n-layer and a player. Trenches are formed in at least the semiconductor structure and separate the die into individually addressable segments. The active layer emits light or optical power having a first color point or spectrum. At least one wavelength converting layer is adjacent the die and converts the light or optical power to light or optical power having at least one second color point or spectrum and limits an energy ratio of the pump light or optical power that passes through the at least one wavelength converting layer unconverted to total light or optical power emitted by the light or optical power emitting device to less than 10%.