Backlight Unit Scattering Film for OLED Light Extraction
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Solution Overview
Problem
Organic light emitting elements used as backlight units in LCDs have high power consumption and low brightness compared to fluorescent lamps, requiring a high-precision process to adjust the light resonance structure, which decreases manufacturing yields and increases costs.
Innovation Solution
A backlight unit design incorporating a substrate, an encapsulating member, an organic light emitting element, and a scattering film with a different refractive index, which prevents total reflection of light and enhances light extraction efficiency, thereby improving brightness and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a light resonance structure is used to improve brightness of organic light emitting elements, then brightness is improved, but manufacturing precision requirements increase and productivity decreases
Solution Approach 1:
A scattering layer is introduced as an intermediary component between the organic light emitting element and the external environment. This scattering layer mediates the light extraction process by scattering light that would otherwise be totally reflected, thereby improving brightness without requiring precise adjustment of the organic light emitting element's internal structure.
Solution Approach 2:
The refractive index of the scattering layer is specifically optimized (set between 1.2 and 1.8) to match the requirements for effective light scattering. By changing the refractive index parameter of the scattering layer, the system achieves improved light extraction efficiency without modifying the organic light emitting element's internal resonance structure.
2Illumination intensity
If a high-precision process is used to adjust the light resonance structure, then brightness is improved, but manufacturing yield decreases
Solution Approach 1:
The scattering layer serves as a mediator that simplifies the manufacturing process. Instead of requiring high-precision adjustment of the organic light emitting element's internal structure, the scattering layer provides a more tolerant manufacturing approach while still achieving the desired light extraction improvement.
Solution Approach 2:
The scattering layer can be implemented as a separate, replaceable component that does not require integration into the core organic light emitting element structure. This approach allows for easier manufacturing and potential cost reduction, as the scattering layer can be applied as a coating or separate layer rather than requiring precision fabrication of the entire device.
3Illumination intensity
If a high-precision process is used to adjust the light resonance structure, then brightness is improved, but manufacturing cost increases
Solution Approach 1:
The scattering layer provides a cost-effective intermediary solution. Rather than investing in high-precision manufacturing equipment and processes to adjust the organic light emitting element's internal structure, the scattering layer can be applied using more conventional, cost-effective manufacturing techniques.
Solution Approach 2:
By optimizing the refractive index parameter of the scattering layer to be between 1.2 and 1.8, the invention achieves effective light scattering with materials and processes that are more cost-effective than high-precision structural adjustment methods.
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
The solution achieves high brightness and low power consumption for organic light emitting elements, maintaining productivity and reducing manufacturing costs by effectively extracting more light and preventing total reflection.
Implementation Method 1
a scattering film interposed between the organic light emitting element and the encapsulating member, or formed over the outer surface of the encapsulating member, wherein the scattering film has a second refractive index different from the first refractive index
Implementation Method 2
the scattering film is configured to substantially prevent total reflection of light emitting from the organic light emitting element
Implementation Method 3
the encapsulating member having a first refractive index... the scattering film has a second refractive index different from the first refractive index
Data Source
AI summary
A backlight unit for a liquid crystal display device (LCD), and an LCD including the same are disclosed. One embodiment of the backlight unit includes an organic light emitting element in which the efficiency of light extraction is improved without decreasing productivity to achieve high brightness and a low consumption power. The backlight unit includes a substrate, an organic light emitting element formed on the substrate, and an encapsulating member attached to the substrate to enclose the organic light emitting element. The backlight unit further includes a scattering film on one of surfaces of the substrate, the organic light emitting element and the encapsulating member to prevent light emitting from the organic light emitting element from being totally reflected.