Extended Light Path Layer for Display Luminous Efficiency
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Solution Overview
Problem
Existing display devices using LEDs face challenges in increasing the light path without thickening the color conversion layer, which is limited by photolithography processes and can lead to color deviations and reduced efficiency.
Innovation Solution
A display device with an extended light path layer made of transparent resin and including color conversion materials like quantum dots, which surrounds the LEDs and thin-film transistors, extending the light path horizontally to improve luminous efficiency without increasing the color conversion layer thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the thickness of the color conversion layer is increased to extend the light path, then the luminous efficiency is improved, but the manufacturing precision deteriorates due to photolithography process limitations
Solution Approach 1:
The patent transitions from increasing thickness (vertical dimension) to extending the light path horizontally by shaping the color conversion layer with inclined side surfaces. This dimensional change allows achieving longer light path length without increasing layer thickness, thereby maintaining photolithography process compatibility while improving luminous efficiency.
Solution Approach 2:
The patent changes the geometric parameters of the color conversion layer by forming inclined side surfaces at specific angles (45 degrees or 60 degrees). This parameter modification extends the horizontal light path length while keeping the vertical thickness within photolithography process capabilities, resolving the contradiction between light path extension and manufacturing precision.
2Loss of energy
If the thickness of the color conversion layer is increased to improve color conversion efficiency, then the light path is extended, but the device thickness increases
Solution Approach 1:
The patent resolves this contradiction by extending the light path in the horizontal direction through inclined side surfaces rather than increasing the vertical thickness. This allows achieving longer light path length for improved color conversion efficiency while maintaining a thin device profile.
3Manufacturing precision
If three separate LEDs are used to implement a pixel, then the color representation is improved, but the device complexity increases due to multiple growth and transfer processes
Solution Approach 1:
The patent extracts only the blue LED growth process, eliminating the need for growing and transferring three separate RGB LEDs. By using a single blue LED with a color conversion layer that converts blue light to red and green wavelengths, the patent simplifies the fabrication process while maintaining full color representation capability.
Solution Approach 2:
The patent uses a color conversion layer containing quantum dots or phosphors that convert blue LED light into red and green wavelengths. This color conversion mechanism enables full RGB color representation using only a single blue LED source, thereby reducing device complexity while preserving 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
This solution enhances the display efficiency by extending the light path and reducing the thickness of the color conversion layer, preventing light leakage and improving color representation, while maintaining a compact device design.
Implementation Method 1
the color conversion layer including quantum dots that can represent red and green colors is disposed to change the wavelength so that light of red and green colors are represented
Implementation Method 2
A light guiding layer including a color conversion material is disposed in the sub-pixel area over the LED and the transistor
Implementation Method 3
A reflective metal electrode is disposed to cover a top portion of the LED and the light guiding layer
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
Provided is a display device (100, 100', 100"). The display device (100, 100', 100") includes a substrate (110) having a sub-pixel area. In some examples, the substrate (110) may have or define a plurality of sub-pixel areas. A light-emitting diode (LED) (130) and a thin-film transistor (120) for driving the LED (130) are disposed in the sub-pixel area. An extended light path layer (150, 650) is disposed on the substrate (110) and is configured to surround the sub-pixel area. Accordingly, it is possible so as to improve the luminous efficiency of the display device (100, 100', 100").