LED Lighting Device with Phosphor-Converted White Light
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Solution Overview
Problem
Conventional lighting devices using multiple LED elements emitting different color ranges face challenges in color tone adjustment during use due to varying forward drop voltages and differing lifespan and deterioration rates, leading to complex circuit configurations and unobtainable light colors over time.
Innovation Solution
A lighting device utilizing two sets of blue LED elements with corresponding yellow and red phosphors, emitting white light with adjustable color temperatures, allowing for easy current control and consistent performance across all LED elements, as all emit lights within the same color range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple LED elements emitting different color ranges are used to adjust white light color, then color tone adjustment capability is improved, but circuit configuration complexity increases due to varying forward drop voltages
Solution Approach 1:
The patent uses LED elements that all emit light within the same color range (blue light at 430-470nm), ensuring they have substantially the same forward drop voltage. This homogeneity in emission characteristics allows for simplified circuit design where a single current control mechanism can uniformly control all LED elements, eliminating the need for complex individual voltage compensation circuits required when using LEDs of different colors.
2Adaptability or versatility
If multiple LED elements emitting different color ranges are used to adjust white light color, then color adjustment capability is improved, but reliability deteriorates due to differing lifespan and deterioration rates
Solution Approach 1:
The patent employs LED elements with identical emission characteristics (blue light at 430-470nm), which inherently have the same lifespan and deterioration characteristics. This uniformity ensures that all LED elements age at the same rate and maintain consistent performance over time, preventing the color instability that would occur if LEDs with different lifespans were used together.
Solution Approach 2:
Instead of using LEDs of different colors to achieve color adjustment (the conventional approach), the patent inverts the approach by using LEDs of the same color (blue) combined with different phosphors to achieve the desired white light color temperature. This inversion eliminates the lifespan inconsistency problem while still achieving color adjustment capability.
3Adaptability or versatility
If LED elements emitting different color ranges are used, then white light color control is improved, but manufacturing complexity increases due to color mixing requirements
Solution Approach 1:
The patent introduces phosphors as intermediary materials that convert the blue light from LED elements into different wavelengths. By using different phosphors (such as yellow phosphor for high color temperature and red phosphor for low color temperature), the patent achieves color adjustment without needing to mix different colored LED lights, thereby simplifying the manufacturing process while maintaining color control capability.
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
Enables easy adjustment and control of white light color over a long period with reduced complexity in circuit design and consistent LED performance, maintaining identical forward drop voltage, lifespan, and deterioration rates across all elements.
Implementation Method 1
a first phosphor included in the first resin to receive a part of blue light from the first blue LED elements and emit first phosphor-converted light
Data Source
AI summary
In a lighting device, a first LED is formed by sealing a blue LED element by a first resin, the first resin having a first phosphor included in the first resin so as to raise a correlation color temperature of an emitted light color; and a second LED is formed by sealing a blue LED element by a second resin, the second resin having a second phosphor included in the second resin so as to lower a correlation color temperature of an emitted light color. The lighting device emits light from white light of a color having a first correlation color temperature to white light of a color having a second correlation color temperature, and the first correlation color temperature is higher than the second correlation color temperature. Consequently, various tones of white light can be more easily adjusted and controlled over a long period.