OLED Display Optical Film with Dual-Lens Light Extraction
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Solution Overview
Problem
OLED displays face challenges in improving luminescent efficiency and color uniformity, particularly at side surfaces, due to issues with light reflection and absorption, which affect image quality and brightness.
Innovation Solution
The OLED display incorporates a substrate with an organic light-emitting device layer, an encapsulation layer, an optical film featuring a reflection control layer with color filters and light shielding parts, and strategically positioned first and second lenses. The first lens is formed adjacent to the light shielding part and has a high refractive index, while the second lens is positioned over the center of sub-pixels and has a convex surface protruding in the light's travel path, enhancing light diffusion and emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a conventional OLED display structure is used, then the device achieves basic light emission and display function, but the luminescent efficiency and brightness at side surfaces are insufficient
Solution Approach 1:
The optical film is segmented into multiple functional layers: a first lens layer with convex surfaces positioned at sub-pixel boundaries to redirect lateral light, and a second lens layer with convex surfaces positioned at sub-pixel centers to enhance forward emission. This segmentation allows different regions of the optical film to perform specialized functions that collectively improve side surface brightness and luminescent efficiency
Solution Approach 2:
The patent introduces a new spatial dimension by positioning lenses at both the boundaries and centers of sub-pixels, creating a three-dimensional optical control architecture. The first lenses at boundaries redirect light that would otherwise be lost laterally, while the second lenses at centers enhance forward emission, effectively utilizing vertical and lateral light paths to improve overall efficiency
2Manufacturing precision
If simple color filters are used in the reflection control layer, then the manufacturing process is simple, but color uniformity and suppression of unwanted color impressions are poor
Solution Approach 1:
The optical film employs local quality differentiation by positioning specific lens types at specific locations: first lenses with particular curvature radii are placed at sub-pixel boundaries to address lateral light reflection, while second lenses with different curvature characteristics are placed at sub-pixel centers to enhance forward emission. This localized optimization achieves superior color uniformity without requiring complex materials throughout the entire structure
Solution Approach 2:
The patent applies asymmetry by using lenses with different geometric properties at different locations within the same optical film. The first lenses have convex surfaces oriented to redirect lateral light, while the second lenses have convex surfaces optimized for forward emission. This asymmetric design allows each lens type to address specific optical issues at its location, achieving excellent color control
3Manufacturing precision
If light shielding parts are added between color filters to suppress unwanted reflections, then color uniformity improves, but light loss increases and brightness decreases
Solution Approach 1:
Instead of simply blocking reflected light with light shielding parts, the patent converts the potentially harmful reflected light into a beneficial resource by using first lenses to redirect it toward the front emission direction. The lenses transform lateral reflections that would otherwise be lost into useful forward-emitted light, improving both color uniformity and overall brightness simultaneously
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 configuration improves the overall luminescent efficiency and brightness of the OLED display, particularly at side surfaces, while suppressing unwanted color impressions, resulting in enhanced image quality and reduced bluish coloration at viewing angles.
Implementation Method 1
a first lens formed below the reflection control layer... the first lens may have a high refractive index... A top surface of the intermediate layer may contact a bottom surface of the first lens
Implementation Method 2
a second lens formed on the reflection control layer... the second lens may have a convex surface protruding in a direction of the travelling path of the light
Implementation Method 3
the reflection control layer includes color filters respectively correspond to the plurality of sub-pixels
Data Source
AI summary
An organic light-emitting diode (OLED) display is disclosed. In one aspect, the display includes an OLED layer including a plurality of OLEDs that respectively form a plurality of sub-pixels and an encapsulation layer disposed over the OLED layer. The OLED display also includes an optical film disposed over the encapsulation layer and comprising a reflection control layer, a first lens disposed below the reflection control layer, and a second lens disposed over the reflection control layer, wherein the reflection control layer comprises i) a plurality of color filters respectively corresponding to the sub-pixels, and ii) a light shielding portion disposed between the color filters. The OLED display further includes an intermediate layer disposed between the encapsulation layer and the optical film, wherein the first lens is disposed over sides of at least one sub-pixels and wherein the second lens is disposed over center portions of selected sub-pixels.