LED Illumination Device with Varying Color Temperatures
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Illumination devices with light-emitting diodes (LEDs) experience color unevenness due to varying light distribution, which worsens with the use of reflection plates or lenses for high illumination intensity, leading to decreased light extraction efficiency and a non-compact design.
Innovation Solution
Arranging multiple light-emitting devices on a substrate with varying color temperatures in a phased manner from the center to the outer circumference, eliminating the need for diffusion processing and maintaining light extraction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If diffusion processing is applied to reflection plates or lenses to reduce color unevenness, then color uniformity is improved, but light extraction efficiency decreases
Solution Approach 1:
The patent applies different color temperatures to different regions (center vs. outer circumference) of the illumination device. By making the light-emitting devices have different characteristics in different locations, color unevenness is reduced without requiring diffusion processing that would reduce light extraction efficiency.
2Stability of the object's composition
If diffusion processing is applied to reflection plates or lenses, then color unevenness is reduced, but device size increases due to larger lens or reflection plate requirements
Solution Approach 1:
The patent varies color temperature locally across different regions of the illumination device to achieve color uniformity without requiring large diffusion-processed optical components, thus maintaining compact device size.
3Power
If multiple light-emitting devices are arranged on a substrate, then light output is increased, but color unevenness becomes more prominent
Solution Approach 1:
The patent arranges light-emitting devices with different color temperatures in different regions (center vs. outer circumference) to compensate for the color unevenness that naturally occurs when multiple LEDs are arranged together, thereby maintaining color uniformity while achieving high light output.
Solution Approach 2:
The patent changes the color temperature parameter of light-emitting devices based on their position in the array. By adjusting this physical parameter spatially, color uniformity is achieved across the entire illumination device while maintaining high overall light output.
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 reduces color unevenness on the irradiation surface without compromising light extraction efficiency, allowing for a more uniform appearance and flexible device shapes, such as rectangles, while avoiding the need for diffusion processing.
Implementation Method 1
a light emitter excited by light from a light-emitting element... a part of the blue light excites a light-emitter included in the resin case to be converted into light in a wavelength of approximately 480 to 780 nm
Data Source
AI summary
An illumination device is provided with an arrangement for reducing color unevenness. A plurality of light-emitting devices are provided, each of which includes a transparent enclosure sealing a light-emitting element and further including a phosphor excited by light emitted from the light-emitting element. A substrate is provided upon which the plurality of light-emitting devices are mounted. The light-emitting devices are provided with predetermined color temperatures that vary in accordance with their position along the substrate to reduce color unevenness, for example increasing in a phased manner from the center of the substrate toward the outer circumference thereof.