Thermal-Sensitive Layer for LED Color Temperature Stability
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Solution Overview
Problem
Light-emitting diodes (LEDs) face efficiency decreases due to thermal heat accumulation, affecting color temperature and light intensity, especially for red chips, which is not effectively addressed by existing electronically controlled methods that increase manufacturing costs.
Innovation Solution
A light-emitting device with a thermal-sensitive layer that varies transmittance or refractive index with temperature changes, allowing for improved color temperature stability by adjusting light transmission based on temperature, using materials like organic compounds, inorganic salts, or liquid crystals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If external electrical current is continuously injected into the LED, then the LED emits light continuously, but thermal heat accumulates causing temperature increase and light-emitting efficiency decrease
Solution Approach 1:
A thermal-sensitive layer is introduced as an intermediary component between the red chip and the observer. This layer automatically adjusts its light transmittance in response to temperature changes, mediating the relationship between thermal heat and light output without requiring external electronic control.
Solution Approach 2:
The thermal-sensitive layer provides self-regulating functionality by automatically changing its optical properties based on temperature. The system serves itself by using the temperature signal to trigger the appropriate compensation action without external intervention or additional control circuits.
2Illumination intensity
If external electrical current is injected into the LED, then light is emitted, but color temperature shifts occur due to different photo decay rates of red and blue chips at elevated temperatures
Solution Approach 1:
The thermal-sensitive layer changes its optical transmission characteristics in response to temperature-induced color shifts. By selectively attenuating or transmitting certain wavelengths based on temperature, the layer compensates for the differential photo decay of red and blue chips, maintaining stable color temperature.
3Stability of the object's composition
If electronically controlled methods are used to solve color temperature differences, then color temperature stability can be improved, but manufacturing cost increases
Solution Approach 1:
The thermal-sensitive layer is implemented as a simple, inexpensive optical filter material that can be easily integrated into the LED structure. This passive component replaces complex electronic control systems, significantly reducing manufacturing cost while achieving the desired color temperature stability.
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 thermal-sensitive layer enhances light intensity and color temperature stability by increasing transmittance at higher temperatures, reducing the impact of thermal heat on LED efficiency and maintaining consistent light output.
Implementation Method 1
a first thermal-sensitive layer (18) formed on a path of the first light (14a), wherein the first thermal-sensitive layer (18) comprises a material characteristic which varies with a temperature change
Implementation Method 2
The light-emitting principle of the LED is the transformation of electrical energy to optical energy. An external electrical current drives electrons provided from the n-type semiconductor layer and holes provided from the p-type semiconductor layer to combine near p-n junction of the active layer. Then, the LED emits light when the electrons and the holes combine.
Data Source
AI summary
A light-emitting device of an embodiment of the present application comprises a substrate; a first semiconductor light-emitting structure formed on the substrate, wherein the first semiconductor light-emitting structure comprises a first semiconductor layer having a first conductivity type, a second semiconductor layer having a second conductivity type and a first active layer formed between the first semiconductor layer and the second semiconductor layer, wherein the first active layer is capable of emitting a first light having a first dominant wavelength; and a first thermal-sensitive layer formed on a path of the first light, wherein the first thermal-sensitive layer comprises a material characteristic which varies with a temperature change.