LED Light Mixing via Segmented Phosphor and Spatial Arrangement
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Solution Overview
Problem
Existing white light sources using LED elements for red, green, blue, and white light suffer from inadequate color rendering properties and complex current control, with blue light excitation reducing the light quantity when combined with a white LED using a phosphor layer.
Innovation Solution
A light-emitting device with a phosphor layer, a blue LED, a red LED, a green LED, and a blue LED positioned further from the phosphor layer, surrounded by a resin frame and encapsulated in sealing resin, with a light-shielding component to enhance color mixing and light emission efficiency, and simplify hue adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If four kinds of LED elements (red, green, blue, white) are provided to improve color rendering property, then color rendering performance is improved, but it becomes difficult to mix the light from these LED elements and control complexity increases
Solution Approach 1:
The invention segments the four LED elements into distinct spatial regions with different configurations. The white LED with phosphor is separated from the blue LED, and all LEDs are positioned at different heights on the mount board. This segmentation simplifies light mixing by preventing interference between different wavelength emissions while maintaining excellent color rendering.
Solution Approach 2:
The patent introduces vertical dimension by mounting the four LED elements at different heights on the mount board. This three-dimensional arrangement allows light from each LED to mix more effectively in the vertical space, improving color rendering while reducing the complexity of horizontal light mixing control.
2Device complexity
If three kinds of LED elements (red, green, blue) are used to generate white light, then device complexity is reduced, but color rendering property becomes inadequate and hue control becomes complicated
Solution Approach 1:
The invention segments the lighting function into two independent systems: a white light generation system using blue LED excites phosphor to produce white light, and a color enhancement system using separate red, green, and blue LEDs. This segmentation achieves excellent color rendering with simplified control compared to managing four independently controlled LEDs.
Solution Approach 2:
The phosphor layer acts as an intermediary that converts blue light into white light with broad spectrum coverage. This intermediary mechanism simplifies the system by eliminating the need for separate red and green LEDs, achieving good color rendering through the phosphor's wavelength conversion properties while maintaining device simplicity.
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
Improves color mixing and light emission efficiency while ensuring high color rendering performance by optimizing the placement and configuration of LED elements and using a phosphor layer to generate white light.
Implementation Method 1
a phosphor layer containing a phosphor, a first LED element to emit white light in combination with fluorescence generated by excitation of the phosphor
Data Source
AI summary
A light-emitting device is provided whose color mixing property and light emission efficiency are improved, while white light with high color rendering performance is ensured by means of four kinds of LED elements emitting red, green, blue, and white light respectively. The light-emitting device includes a phosphor layer containing a phosphor, a first LED element to emit white light in combination with fluorescence generated by excitation of the phosphor, a second LED element to emit red light, a third LED element to emit green light, a fourth LED element to emit blue light placed more distant from the phosphor layer compared to the second and third LED elements, a substrate with the first to fourth LED elements mounted on a common mounting surface, a resin frame surrounding at least a part of an outer circumference of the substrate, a sealing resin injected inside the resin frame and on the substrate to encapsulate the first to fourth LED elements, and a light-shielding component placed on an upper surface of the sealing resin to cover at least the first LED element.