LED Filament Structure with Chromic Layer for Tunable Color Temperature
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Solution Overview
Problem
Conventional LED light bulbs lack the ability to project 360-degree light and have an unattractive appearance, differing significantly from incandescent bulbs in terms of lighting effect, color temperature, and brightness control.
Innovation Solution
An LED filament structure comprising a substrate, LED chip units with different emission peak wavelengths, a first chromic layer that transitions between inactivated and activated states, and a light conversion layer to produce variable color temperature and brightness by controlling the passage of excitation light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an LED filament structure with multiple LED chip units and a chromic layer is used, then the lighting effect becomes similar to incandescent bulbs with tunable color temperature and brightness, but the device complexity increases
Solution Approach 1:
The LED filament is divided into multiple LED chip units (first and second LED chip units) with different emission peak wavelengths, allowing independent control of different color components to achieve tunable color temperature and brightness while maintaining a structure similar to traditional incandescent filaments
Solution Approach 2:
The chromic layer is designed to be switchable between transparent and opaque states, enabling dynamic adjustment of light transmission and color temperature. This dynamic property allows the system to simulate the warm-up behavior of incandescent bulbs and provide tunable lighting effects
2Ease of manufacture
If a conventional LED light bulb structure is used, then the manufacturing process is simplified, but the ability to project 360-degree light and aesthetic appearance are compromised
Solution Approach 1:
The LED filament is designed with a curved or spiral configuration that extends throughout the bulb volume, enabling 360-degree light emission in all directions. This curved structure maintains aesthetic similarity to traditional incandescent filaments while achieving omnidirectional illumination
3Device complexity
If LED chips with fixed emission wavelengths are used, then the device complexity is reduced, but the ability to achieve tunable color temperature is lost
Solution Approach 1:
Different segments of the LED filament use LED chips with different emission peak wavelengths (e.g., first LED chip units with blue wavelength, second LED chip units with green wavelength). This local differentiation allows each segment to contribute to different color components, enabling overall color temperature tuning while keeping individual chip designs simple
Solution Approach 2:
The system combines multiple LED chip types with different emission characteristics and uses a chromic layer material that changes optical properties. This composite approach creates tunable color temperature functionality while maintaining relative simplicity in individual component design
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 LED filament structure achieves a lighting effect similar to incandescent bulbs by emitting lights with tunable color temperature and brightness, enhancing heat dissipation and aesthetic appeal while simplifying manufacturing processes.
Implementation Method 1
The first chromic layer is configured to transition between an inactivated state and an activated state. In the inactivated state, the first chromic layer prevents the excitation light emitted from the one of the first and second LED chips from passing therethrough... In the activated state, the first chromic layer allows the excitation light emitted from the one of the first and second LED chips to pass therethrough
Implementation Method 2
The light conversion layer is disposed on and covers the LED chip unit and the first chromic layer, and includes a light conversion material... the excitation light emitted from the other one of the first and second LED chips passes through the light conversion layer and excites the light conversion material to emit a first excited light... the excitation lights emitted from the first and second LED chips pass through the light conversion layer and excite the light conversion material to obtain a second excited light
Data Source
AI summary
A light-emitting diode (LED) filament structure includes a substrate, an LED chip unit, a first chromic layer, and a light conversion layer. The LED chip unit is disposed on the substrate, and includes first and second LED chips emitting different excitation lights. The first chromic layer covers the first and second LED chips. The light conversion layer covers the LED chip unit and the first chromic layer. The first chromic layer is configured to transition between an inactivated state and an activated state to prevent or allow the excitation light from the first or second LED chips to pass therethrough, so as to excite the light conversion layer to emit different excited lights having different color temperatures.