Light Source Apparatus Using Two-Color LED Blocks for Color Space Control
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Solution Overview
Problem
The high manufacturing costs and increased wire complexity of using RGB LEDs in liquid crystal display (LCD) backlight assemblies necessitate a more efficient method for driving light sources to achieve both standard RGB and ADOBE RGB color spaces.
Innovation Solution
A two-way dimming method utilizing light-emitting blocks with a first-color and second-color light source, where the second-color light source includes a third-color chip and fourth-color phosphor, compensates driving currents based on image data to generate target color coordinates and luminance, reducing the number of LEDs and wires required.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If RGB LEDs are used to generate standard RGB and ADOBE RGB color spaces, then color reproducibility is improved, but manufacturing costs and device complexity increase
Solution Approach 1:
The patent uses only two LED types (blue LED and yellow-green LED) to achieve multiple color spaces (standard RGB and ADOBE RGB). By making these two LED types perform multiple functions through phosphor combination and PWM dimming control, the system eliminates the need for separate red, green, and blue LEDs, thereby reducing device complexity while maintaining color space versatility
Solution Approach 2:
The patent changes the parameters of existing LEDs by using different phosphor materials and combinations on blue and yellow-green LEDs to generate different colors. By adjusting phosphor composition and using PWM dimming to vary emission intensities, the system achieves multiple color spaces without adding more LED types, thus reducing manufacturing costs and wire complexity
2Reliability
If RGB LEDs are disposed in packages, then color reproducibility is improved, but manufacturing costs increase
Solution Approach 1:
The patent extracts the red and green light generation functions from separate red and green LEDs by using phosphor conversion on blue and yellow-green LEDs. This extraction eliminates the need to manufacture and assemble multiple separate LED packages, reducing manufacturing costs while maintaining color reproducibility through the phosphor-based color generation method
Solution Approach 2:
The patent replaces expensive multi-color LED packages with simpler, cheaper single-color LED packages (blue and yellow-green) combined with phosphor materials. This substitution uses more economical components to achieve the same color reproduction function, significantly reducing manufacturing costs
3Adaptability or versatility
If RGB LEDs are used, then color space coverage is improved, but power consumption increases
Solution Approach 1:
The patent employs PWM (pulse width modulation) dimming control to periodically switch the blue and yellow-green LEDs on and off at different duty cycles. This periodic action allows precise control of light output intensity for each LED type, enabling efficient power management that reduces overall power consumption while maintaining the ability to generate both standard RGB and ADOBE RGB color spaces
Solution Approach 2:
The patent uses partial action by selectively activating only the necessary LED types (blue and yellow-green) and their corresponding phosphors to generate the required colors for both color spaces. This partial activation approach avoids the excessive power consumption that would result from driving all three RGB LED types at full intensity, achieving color space coverage with optimized power usage
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
This approach decreases manufacturing costs and power consumption while enhancing reliability and color reproducibility by integrating LEDs of two colors, achieving improved power efficiency and reduced distortion in color coordinates.
Implementation Method 1
a fourth-color phosphor disposed on the third-color chip and being formed as one package to emit the second-color light therefrom
Data Source
AI summary
A light source apparatus includes light-emitting blocks, a local dimming control part and a light source driving part driving. The light-emitting blocks include a first-color light source which emits first-color light and a second-color light source which emits second-color light. The second-color light source includes a third-color chip and a fourth-color phosphor disposed on the third-color chip, and is disposed as one package to emit the second-color light therefrom. The local dimming control part compensates a driving current of the first-color light source and a driving current of the second-color light source of each of the light-emitting blocks. The light source driving part drives the first-color light source and the second-color light sources based on the driving current of the first-color light source and the a driving current of the second-color light source, respectively, each compensated by the local dimming control part.