LED Illumination Device with Dual Refractive Index Sealing
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Solution Overview
Problem
Current light-emitting diode (LED) illumination devices face challenges in achieving high light extraction efficiency and uniform light intensity on an illumination plane, particularly when used as backlight sources for display panels, due to the high directivity of extracted light.
Innovation Solution
The use of a sealing structure comprising a light-emitting diode sealed by a high refractive index transparent material member, which is further sealed by a low refractive index transparent material member, increases the divergence angle of light radiation, enhancing light extraction efficiency and uniformity of light intensity on the illumination plane. Additionally, a combination of LEDs emitting different wavelengths (red, green, and blue) are sealed together to mix their light, improving color quality and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a light-emitting diode is sealed with a high refractive index resin to enhance light extraction efficiency, then the light extraction efficiency is improved, but the extracted light has high directivity which reduces uniformity of light intensity on the illumination plane
Solution Approach 1:
The sealing structure is divided into two distinct segments: an inner high refractive index transparent material member (first sealing member) for light extraction enhancement, and an outer low refractive index transparent material member (second sealing member) for light diffusion. This segmentation allows each material to perform its specialized function without interfering with the other, resolving the contradiction between light extraction efficiency and uniformity.
Solution Approach 2:
The low refractive index transparent material member acts as an intermediary between the high refractive index material and the external environment. It receives the highly directional light from the LED through the high refractive index material and diffuses it to achieve uniform illumination, serving as a mediator that transforms the light characteristics while maintaining extraction efficiency.
2Illumination intensity
If multiple light-emitting diodes emitting different wavelengths are used to improve color quality, then the color quality of mixed light is enhanced, but the device complexity increases
Solution Approach 1:
Multiple light-emitting diodes emitting different wavelengths (red, green, and blue) are merged into a single sealing structure with a common high refractive index transparent material member. This combining approach allows the LEDs to be controlled as a unified system while maintaining their individual wavelength characteristics, achieving high color quality without proportionally increasing device complexity.
Solution Approach 2:
The high refractive index transparent material member serves multiple functions simultaneously: it enhances light extraction for all wavelength types, provides structural support for multiple LEDs, and enables the mixed light output. This multi-functionality reduces the need for separate components for each LED, thereby controlling device complexity while achieving high color quality.
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 improved light extraction efficiency, uniform light intensity, and high color quality on the illumination plane, making the LED illumination device suitable for display applications by efficiently dispersing light and controlling its direction.
Implementation Method 1
a light-emitting diode is sealed with a high refractive index resin and the resulting arrangement is further sealed at its periphery with a low refractive index resin
Implementation Method 2
the extracted light from the light-emitting diode has a high directivity, so that the above invention does not appear to intend uniformity of light intensity on an illumination plane
Implementation Method 3
at least two selected from a group consisting of a light-emitting diode capable of emitting light in a red wavelength region, a light-emitting diode capable of emitting light in a green wavelength region and a light-emitting diode capable of emitting light in a blue wavelength region
Data Source
AI summary
An illumination device has a plurality of sealing structures each including a light-emitting diode, sealed by a high refractive index transparent material member which is further sealed by a low refractive index transparent material member. To increase a divergence angle of light radiation, the portion of the high refractive index transparent material member which covers an upper surface of the light-emitting diode is structured so as to satisfy a relation H>(L/2)/tan {sin−1(n1/n2)}, where H represents a thickness of the high refractive index transparent material member measured at the central portion of the upper surface of the light-emitting diode, L represents the length of one side of the upper surface of the light-emitting diode, n1 represents the refractive index of the high refractive index transparent material member and n2 represents the refractive index of the low refractive index transparent material member.