Hemispherical Groove Light Extraction Modules for OLED Substrates
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Solution Overview
Problem
Organic light emitting diode (OLED) display devices suffer from significant light loss due to total reflection between the organic luminescent material and the substrate, resulting in only about 20% of light being emitted into the air, which is inadequate for display technology requirements.
Innovation Solution
A display substrate with hemisphere-shaped groove light extraction modules on a glass substrate, coated with macromolecule organic materials of higher refractive index, is used to reduce the refraction angle of emitted light, allowing more light to exit and improve luminous efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a scattering means or lens is disposed at the outer surface of the substrate to extract trapped light, then light extraction efficiency is improved, but halo effect occurs and it is only suitable for lighting not display technology
Solution Approach 1:
The patent applies local quality by creating hemispherical groove structures at specific locations corresponding to each sub-pixel rather than using a uniform scattering layer across the entire substrate. This localized approach allows light extraction to be concentrated at the light-emitting regions, improving efficiency while avoiding the halo effect that would occur with diffuse scattering means.
Solution Approach 2:
The patent employs spheroidality by forming hemispherical groove structures on the substrate surface. The curved hemispherical shape acts as a microlens to focus and extract light efficiently from each sub-pixel region, achieving high light extraction efficiency without the halo effect associated with conventional scattering means or planar lenses.
2Loss of energy
If conventional light extraction methods are used, then some light can be extracted, but only about 20% of light can be emitted into the air due to total reflection
Solution Approach 1:
The hemispherical groove structures utilize the curved surface to refract light at multiple angles, enabling light that would otherwise undergo total internal reflection to be extracted into the air. The spherical shape acts as a microlens that focuses and directs light outward, significantly improving the proportion of light emitted into the air.
Solution Approach 2:
The patent changes the physical parameter of the substrate surface by creating hemispherical grooves with specific dimensions (depth and diameter ratios). This geometric parameter change modifies the light path and refraction angles, enabling efficient light extraction while maintaining the structural integrity of the display substrate.
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 effectively increases the luminous efficiency and display effect by reducing the refraction angle of light emitted from sub-pixels, enhancing the overall performance of OLED display devices.
Implementation Method 1
the light will be subjected to, in a waveguide mode, a total reflection between a luminescent layer and a transparent electrode as well as a total reflection in the glass substrate... only about 20% of the light can be emitted into the air
Data Source
AI summary
A display substrate, a manufacturing method thereof, and a display panel are disclosed. The display substrate includes a glass substrate; plural sub-pixels; and plural light extraction modules disposed on the glass substrate at plural regions in one-to-one correspondence with the plural sub-pixels; wherein each of the light extraction modules has a hemisphere-shaped groove structure. By manufacturing the plural light extraction modules each having a hemisphere structure and a higher refractive index on the glass substrate in one-to-one correspondence with the plural sub-pixels, the refraction angle of the light that is emitted from each of the sub-pixels and incident onto the glass substrate can be decreased, so that more light can be emitted out; in this way, it is possible to improve the luminous efficiency of the display substrate and hence the display effect of the display device.