Illumination System with Local and Remote Luminescent Elements
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing illumination systems, particularly those used in LCD displays, face challenges in achieving uniform intensity and color output due to variations in phosphor layer thickness and optical characteristics of associated objects, leading to undesirable spatial intensity and color variations.
Innovation Solution
The implementation of a semiconductor light-emitting device with a first luminescent element for local light conversion and a second luminescent element for remote light conversion, allowing for the combination of primary colors to form the output light, with the effective thickness of the second luminescent element chosen to correct the color point and minimize sensitivity to thickness variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a phosphor layer is used for wavelength conversion in the illumination system, then the color output can be adjusted to meet requirements, but variations in phosphor layer thickness cause spatial intensity and color variations
Solution Approach 1:
The illumination system is divided into multiple independent light-emitting devices arranged in an array, with each device containing its own luminescent element. This segmentation allows each unit to operate independently, so that thickness variations in individual phosphor layers do not propagate across the entire illumination area, thereby maintaining spatial uniformity while preserving color adjustment capability.
Solution Approach 2:
Each light-emitting device in the array is configured with its own luminescent element having locally optimized characteristics. The effective thickness of the second luminescent element is specifically chosen for each device to correct the color point to attain a desired target point, allowing local adaptation to compensate for manufacturing variations while maintaining overall uniformity.
2Measurement precision
If the effective thickness of the second luminescent element is increased to correct color point, then the color accuracy improves, but the sensitivity to thickness variations increases
Solution Approach 1:
The second luminescent element provides a fine-tuning correction that is deliberately kept partial rather than complete. By using a smaller effective thickness for the second luminescent element compared to the first, the system achieves sufficient color point correction without over-correcting, thereby reducing sensitivity to thickness variations while maintaining adequate color accuracy.
3Productivity
If multiple luminescent elements are used for light conversion, then the light output requirements can be met, but the device complexity increases
Solution Approach 1:
Multiple light-emitting devices with luminescent elements are arranged in an array configuration and operated simultaneously to produce the required light output. This merging approach distributes the conversion function across multiple identical or similar units, achieving high light output quality while keeping individual device complexity low and enabling standardized manufacturing.
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 results in a more uniform intensity and color output, reducing spatial variations and enabling standardization of the illumination system while matching it to the associated object, thereby improving the consistency and quality of the light emitted.
Implementation Method 1
luminescent elements are frequently employed to absorb the photons, produced by the light-emitting device, which have a certain wavelength spectrum, and to emit photons having a different wavelength spectrum. Phosphors are a well-known example of luminescent elements, and the process of absorption and subsequent emission is often referred to as conversion, or wavelength conversion.
Implementation Method 2
a second luminescent element, physically separated from the semiconductor light-emitting device, and configured to absorb at least part of the light of the first or second primary colors and to emit light of a third primary color
Data Source
AI summary
The invention provides an illumination system comprising a light-emitting device which excites a first luminescent element, which forms part of the light-emitting device. The light emitted from the first luminescent element and/or the light emitted by the light-emitting device excite a second luminescent element, physically separated from the light-emitting device. By employing two luminescent elements, the first element in the light- emitting device, and the second element physically separated from the light-emitting device, such as on a cover plate, the conversion of light produced by the light-emitting device is performed at both a "local" and a "remote" location, respectively, and the amount of luminescent material required at the remote location may be reduced compared to the situation of the prior art where the light conversion was only performed at a remote location.