LED Light Bulb With Phosphor Screen Globe For Color Rendering
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Solution Overview
Problem
Conventional LED light bulbs with blue LEDs and yellow phosphors suffer from poor color rendering properties, glare, and limited light distribution angles, leading to uneven luminance and insufficient red light emission.
Innovation Solution
An LED light bulb design featuring an ultraviolet to violet light-emitting LED chip module with a phosphor screen on the inner surface of the globe, using a combination of blue, green, and red phosphors to produce white light, which is surface-emitted in all directions, reducing glare and enhancing color rendering and light distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If blue LED and yellow phosphor are combined to generate white light, then brightness is easy to be secured, but color rendering properties deteriorate
Solution Approach 1:
The patent applies local quality by using different phosphor materials in different regions of the globe inner surface. Specifically, red phosphor is applied to specific regions to supplement red light components, while yellow phosphor is applied to other regions. This regional differentiation allows the system to maintain high brightness from the blue LED while improving color rendering properties through localized red light emission.
2Illumination intensity
If blue LED and yellow phosphor are combined, then white light is obtained by color mixture, but light distribution angle becomes limited and glare increases
Solution Approach 1:
The patent segments the light emission function by separating the blue LED light source from the phosphor conversion layer. The blue LED emits light that is then converted to white light by yellow phosphor on the globe inner surface. This segmentation allows the light to be emitted from the entire globe surface rather than a single point, thereby increasing the light distribution angle and reducing glare while maintaining white light output.
3Power
If blue LED light is used for white light generation, then luminance is concentrated, but luminance becomes uneven and local dazzle increases
Solution Approach 1:
The patent transitions from point-source emission to surface emission by applying phosphor material to the inner surface of the globe. The blue LED light is converted to white light across the entire globe surface, distributing the luminance in three-dimensional space rather than concentrating it in one direction. This dimensional change eliminates local dazzle while maintaining overall luminance output.
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 solution improves color rendering index, reduces glare, and increases the light distribution angle, providing more even and soft lighting similar to incandescent lamps, while maintaining stability and luminance over time.
Implementation Method 1
an ultraviolet to violet light-emitting LED chip mounted on a substrate
Implementation Method 2
A phosphor screen separated from the LED chips is provided on an inner surface of the globe. The phosphor screen has a color in which a* is -10 or more and +10 or less, b* is 0 (zero) or more and +30 or less, and L* is +40 or more when a body color thereof is represented by an L*a*b* color system
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
An LED light bulb 1 according to the embodiment includes an LED module 2, a base part 3 on which the LED module 2 is disposed, and a globe 4 attached to the base part 3. The LED module 2 includes an ultraviolet to violet light-emitting LED chip 8 mounted on a substrate 7. A lighting circuit and a bayonet cap 6 are provided at the base part 3. A phosphor screen 9 absorbing the ultraviolet to violet light emitted from the LED chips and emitting white light is provided at an inner surface of the globe 4. The phosphor screen 9 has a color in which a* is -10 or more and +10 or less, b* is 0 (zero) or more and +30 or less, and L* is +40 or more when a body color thereof is represented by an L*a*b* color system.