Blue LED Light Source Module with Wavelength Conversion for Color Stability
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Solution Overview
Problem
Conventional LED light sources with red, green, and blue chips face issues due to different aging speeds and brightness decaying speeds, leading to color temperature shifts and complex driving circuit designs.
Innovation Solution
A light source module using blue-light emitting elements with a light diffusing layer and a wavelength converting layer that converts blue light into red and green light, reducing the complexity of the driving circuit and product defects, and incorporating a blue-light reflecting layer to enhance color purity and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If red, green and blue LED chips are arranged in a package to mix into white light, then white light can be produced, but the color temperature shifts during long-term operation due to different aging speeds and brightness decaying speeds of the different LED chips
Solution Approach 1:
The patent segments the white light production process by separating the blue light source from the red and green light generation. Instead of using three different LED chips, it uses a single blue LED chip array combined with wavelength converting layers containing red and green phosphors. This segmentation eliminates the aging rate mismatch problem while maintaining white light output.
Solution Approach 2:
The patent changes the fundamental parameter of light generation from direct emission by multiple LED chips to wavelength conversion from a single blue LED chip. By using phosphors with different emission characteristics (red and green) converted from blue light, it achieves stable color temperature while producing white light.
2Illumination intensity
If different powers are applied to red, green and blue LED chips respectively, then the desired light output can be achieved, but the driving circuit design becomes complicated
Solution Approach 1:
The patent merges the control of multiple LED chips into a single control system. By using only blue LED chips that are all driven by the same driving circuit, it eliminates the need for separate power control circuits for red, green, and blue chips, thereby simplifying the overall driving circuit design.
Solution Approach 2:
The blue LED chips serve multiple functions: they directly provide blue light and simultaneously serve as the excitation source for both red and green phosphors through wavelength conversion. This multi-functionality eliminates the need for separate LED chips and their corresponding control circuits for different colors.
3Device complexity
If blue-light emitting elements are used with wavelength converting layers to produce red and green light, then the driving circuit complexity is reduced, but the color purity may be affected by blue light leakage
Solution Approach 1:
The patent extracts and removes the harmful blue light component that leaks through the phosphor layers by introducing a blue light absorbing layer. This layer selectively absorbs the unwanted blue light while allowing the converted red and green light to pass through, thereby improving color purity without affecting the simplified driving circuit architecture.
Solution Approach 2:
The patent converts the harmful effect of blue light leakage into a beneficial control mechanism. By intentionally designing a blue light absorbing layer, it transforms the problematic blue light that was causing color purity issues into a targeted element that can be selectively managed and removed, thereby improving overall color accuracy.
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 reduces product costs and complexity, avoids defects from different brightness decaying speeds, and improves color purity and conversion efficiency by using blue LED chips with a light diffusing and wavelength converting structure, along with a blue-light reflecting layer.
Implementation Method 1
the wavelength converting layer includes a first converting layer disposed in the first region, a second converting layer disposed in the second region, and a transparent layer disposed in the third region. A blue light generated from one of the blue-light emitting elements and emitted from the first region is converted to a red light via the first converting layer. A blue light generated from another one of the blue-light emitting elements and emitted from the second region is converted to a green light via the second converting layer.
Implementation Method 2
The light diffusing layer is disposed on the lighting structure.
Implementation Method 3
The blue-light reflecting layer is disposed on the cover plate and covers the first converting layer and the second converting layer.
Data Source
AI summary
A light source module includes a lighting structure, a light diffusing layer, a wavelength converting layer, and a cover plate. The lighting structure includes a plurality of light emitting elements that are all blue-light emitting elements. The light diffusing layer is disposed on the lighting structure, the wavelength converting layer is disposed on the light diffusing layer, and the cover plate is disposed on the wavelength converting layer.