UV-LED Illumination with Composite Phosphors for High CQS
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Solution Overview
Problem
Current illumination devices, particularly those using white LEDs, face challenges in accurately rendering colors, especially highly saturated colors, due to limitations in the Color Rendering Index (CRI) metric, which focuses on low to medium chromatic saturation samples and penalizes increases in chromatic saturation, leading to poor performance with peaked spectral distributions.
Innovation Solution
The use of UV or NUV pumped LEDs coated with a composition of phosphors such as red, yellow, blue, green, or violet phosphors, combined with wavelength selection devices and lenses, to emit electromagnetic radiation within the 200-440 nanometer range, allowing for selective wavelength adjustment and improved color rendering through the Color Quality Scale (CQS) metric, which includes 15 high chromatic saturation samples spanning the entire hue circle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional white LEDs are used for illumination, then the device structure is simple and manufacturing is easy, but the color rendering accuracy for highly saturated colors is poor due to limitations in CRI metric
Solution Approach 1:
The patent applies composite materials by combining multiple phosphors with different emission characteristics (yellow phosphor for saturation, red phosphor for warmth, green phosphor for natural rendering) on the LED chip. This composite phosphor approach enables the illumination device to achieve high color rendering accuracy across the entire visible spectrum while maintaining a relatively simple single-chip structure, resolving the contradiction between measurement precision and device complexity.
Solution Approach 2:
The patent implements local quality by strategically positioning different phosphor materials at specific locations on the LED chip surface. Each phosphor region emits at specific wavelengths optimized for particular color rendering requirements, allowing precise control over the spectral output in different local areas of the illumination source, thereby improving overall color rendering accuracy without increasing overall device complexity.
2Measurement precision
If the Color Rendering Index (CRI) metric is used to evaluate illumination quality, then the evaluation focuses on low to medium chromatic saturation samples, but this leads to poor performance with peaked spectral distributions and fails to accurately render highly saturated colors
Solution Approach 1:
The patent applies parameter changes by modifying the spectral distribution parameters of the illumination source through careful selection and combination of phosphors with different emission profiles. This enables the system to achieve peaked spectral distributions that are optimized for rendering highly saturated colors while maintaining good overall color rendering, thereby improving measurement precision and adaptability simultaneously.
Solution Approach 2:
The composite phosphor approach allows the illumination device to produce a balanced spectral distribution that performs well across both CRI and CQS evaluation metrics. By combining phosphors with complementary emission characteristics, the system achieves high color rendering accuracy for both low-to-medium saturation colors (CRI strength) and highly saturated colors (CQS strength), resolving the adaptability issue.
3Measurement precision
If UV or NUV pumped LEDs with multiple phosphors are used, then color rendering quality is significantly improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent applies segmentation by dividing the phosphor coating into distinct regions on the LED chip, with each region containing specific phosphor materials optimized for particular wavelength ranges. This segmented approach simplifies the manufacturing process by allowing independent optimization and quality control of each phosphor region, while still achieving superior overall color rendering quality through the combined effect of all segments.
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 achieves high color rendering scores, enabling subtle color expressions and enhanced medical evaluations by optimizing the electromagnetic spectrum for better visual clarity and contrast, overcoming the limitations of conventional LEDs.
Implementation Method 1
at least one light emitting diode emitting electromagnetic radiation with a wavelength from about 200 nanometers to about 440 nanometers
Implementation Method 2
A composition of phosphors coat the at least one light emitting diode. The composition of phosphors may comprise a red phosphor, yellow phosphor, a blue phosphor, a green phosphor, an orange phosphor, a violet phosphor
Implementation Method 3
At least one wavelength selection device positioned in the path to selectively permit electromagnetic radiation of a particular range of wavelengths to pass through
Implementation Method 4
A mirror to change a direction of the path
Implementation Method 5
at least one lens to diverge the electromagnetic radiation
Data Source
AI summary
A method and apparatus are disclosed for a LED used in a medical device emitting a wavelength from about 200 nanometers to about 440 nanometers along a path. A composition of phosphors coats the LED to broaden the electromagnetic spectrum from about 200 nanometers to about 780 nanometers. A filter is positioned in the path to selectively permit electromagnetic radiation of a particular range of wavelengths to pass through. The medical device is used to provide a broad spectral source for medical diagnosis.